WO2012128238A1 - Fuel cell - Google Patents

Abstract

Provided is a fuel cell comprising a unit cell which comprises an anode electrode, an electrolyte membrane and a cathode electrode in this order, a fuel supply unit which is arranged on the anode electrode side of the unit cell and can supply a fuel to the anode electrode, and a heat discharge layer which is arranged between the unit cell and the fuel supply unit, wherein the heat discharge layer has a through-hole which is penetrated in the thickness direction and a communication passage which is arranged at the peripheral part of the heat discharge layer and communicates between the through-hole and exterior of the heat discharge layer. In the fuel cell, a first interposition layer which is a hydrophobic porous layer may be arranged between the heat discharge layer and the fuel supply unit, and a second interposition layer which has a bubble point of 30 kPa or more as measured using methanol as a measurement medium may be arranged between the first interposition layer and the fuel supply unit.

Description

Fuel cell

The present invention relates to a fuel cell.

Fuel cells can be used for a long time, allowing users to use the electronic equipment longer than before by refilling the fuel once, and even if the user runs out of the battery on the go, the fuel cell does not have to wait for charging. From the point of convenience that an electronic device can be used immediately by purchasing and replenishing it, there is an increasing expectation for practical use as a new power source for portable electronic devices that support the information society.

Fuel cells are classified into phosphoric acid type, molten carbonate type, solid electrolyte type, solid polymer type, direct alcohol type, etc., according to the classification of the electrolyte material and fuel used. In particular, solid polymer fuel cells and direct alcohol fuel cells that use an ion exchange membrane, which is a solid polymer, as the electrolyte material can achieve high power generation efficiency at room temperature. Practical application as a small fuel cell is under study.

The direct alcohol fuel cell that uses alcohol or an aqueous alcohol solution as the fuel has a simplified structure of the fuel cell because the fuel storage chamber can be designed relatively easily compared to the case where the fuel is a gas. Space-saving is possible, and the expectation as a small fuel cell for the purpose of application to portable electronic devices is particularly high.

In a direct alcohol fuel cell that uses a cation exchange membrane as an electrolyte membrane, when fuel (alcohol or an alcohol aqueous solution) is supplied to the anode electrode, the fuel is oxidized and gas such as carbon dioxide (hereinafter referred to as “by-product gas”). And protons are generated. For example, when methanol is used as the alcohol,
CH ₃ OH + H ₂ O → CO ₂ ↑ + 6H ⁺ + 6e ⁻
As a by-product gas, carbon dioxide is generated on the anode electrode side by the oxidation reaction represented by the formula:

Protons generated on the anode electrode side are transmitted to the cathode electrode side through the electrolyte membrane. And the oxygen in the air supplied to the proton and the cathode electrode,
3 / 2O ₂ + 6H ⁺ + 6e ⁻ → 3H ₂ O
The reduction reaction represented by the formula is caused to produce water. At this time, electrons pass through an external electronic device (load), move from the anode electrode to the cathode electrode, and electric power is taken out.

A fuel cell using a liquid fuel (hereinafter also referred to as “liquid fuel”), such as a direct alcohol fuel cell, has a liquid supply system that supplies liquid fuel to the anode electrode in a liquid state, There is a gas supply system for supplying a vaporized component to the anode electrode. For example, in International Publication No. 2008/023633 (Patent Document 1), a vaporized component (hereinafter, also referred to as “vaporized fuel”) of liquid fuel stored in the liquid fuel storage chamber between the liquid fuel storage chamber and the anode electrode. A gas supply type DMFC (Direct Methanol Fuel Cell) is provided, which is provided with a gas-liquid separation membrane that permeates.

On the other hand, fuel cells can be broadly classified into passive type and active type from the classification based on the fuel and air supply system. A passive fuel cell is a fuel cell that supplies fuel and air to the anode and cathode, respectively, without using auxiliary equipment that uses external power such as a pump or a fan. Therefore, there is a high expectation for use in portable electronic devices.

In a fuel cell, particularly a small fuel cell, the temperature inside the cell rises due to heat generated by power generation, which promotes the vaporization of the liquid fuel contained in the fuel storage chamber and causes a crossover phenomenon (excess in the anode electrode). The fuel supplied to the battery reaches the cathode electrode through the electrolyte membrane, causing a catalytic reaction at the cathode electrode), and the internal temperature of the battery is likely to run away due to a vicious cycle in which the battery temperature further rises. It was. Further, when the internal pressure rises due to the temperature rise inside the battery as described above, the fuel cell may be deformed, and there is a problem in terms of reliability.

In order to solve the above problem, Patent Document 1 discloses a distance L from a gas-liquid separation membrane disposed on a liquid fuel storage chamber to an anode conductive layer of a membrane electrode assembly in a passive DMFC using a gas supply method. It has been proposed to be more than 2 mm and not more than 5 mm.

International Publication No. 2008/023633

In the fuel cell described in Patent Document 1, as described above, the distance L is set to more than 2 mm in order to thermally separate the power generation unit (membrane electrode assembly) and the fuel supply unit (liquid fuel storage chamber). In this case, it is difficult to reduce the thickness of the fuel cell.

Further, in a fuel cell in which a gas-liquid separation membrane capable of gas permeation is disposed between a liquid fuel storage chamber and an anode electrode in order to adopt a gas supply method as described in Patent Document 1, the anode electrode The by-product gas generated in the step passes through the gas-liquid separation membrane and enters the liquid fuel storage chamber. The intrusion of the by-product gas into the liquid fuel storage chamber reduces the amount of liquid fuel that contacts the gas-liquid separation membrane, resulting in a decrease in the amount of vaporized fuel supplied to the anode electrode and a stable supply of vaporized fuel. And the output stability of the fuel cell is lowered.

An object of the present invention is to provide a fuel cell that can prevent runaway of the internal temperature of the battery and an increase in internal pressure, and can be thinned. Another object of the present invention is to provide a fuel cell with good output stability.

The present invention includes a unit cell having an anode electrode, an electrolyte membrane, and a cathode electrode in this order, a fuel supply unit that is disposed on the anode electrode side of the unit cell and supplies fuel to the anode electrode, a unit cell, and a fuel supply The exhaust heat layer is provided between the through-hole that penetrates in the thickness direction and the peripheral portion of the exhaust heat layer, and communicates the through-hole and the outside of the exhaust heat layer. A fuel cell [A] having a communication path is provided.

The exhaust heat layer can have two or more through holes and one or more communication paths that connect any one of the through holes to the outside of the exhaust heat layer. The opening ratios of the through holes are preferably 50% or more in total. The thickness of the through hole (exhaust heat layer) is preferably 100 to 1000 μm. The ratio between the total cross-sectional area S ₁ of the communication path and the total area S ₀ of the side surface of the exhaust heat layer is preferably greater than ₀ and less than 0.3. The exhaust heat layer can be made of, for example, a metal plate in which a through hole and a communication path are formed by etching.

The fuel cell [A] of the present invention preferably further includes a first intervening layer that is a hydrophobic porous layer disposed between the exhaust heat layer and the fuel supply unit.

The fuel supply unit is composed of a space in which the anode electrode side is open, and may include a fuel supply chamber for circulating or containing liquid fuel (liquid fuel). In a preferred embodiment of the fuel cell [A], the fuel supply unit includes a fuel supply chamber for circulating the liquid fuel, and a fuel storage chamber connected to the fuel supply chamber and containing the liquid fuel. In this embodiment, the fuel cell [A] can further include a pumping means for pumping the liquid fuel stored in the fuel storage chamber to the fuel supply chamber.

In another preferred embodiment of the fuel cell [A], the fuel supply unit is arranged on the side of the fuel supply chamber in addition to the fuel supply chamber, and includes a fuel storage chamber for containing liquid fuel, a liquid A member made of a material exhibiting a capillary action with respect to the fuel, one end of which is disposed at a position capable of contacting the liquid fuel accommodated in the fuel storage chamber, and the other end disposed in the fuel supply chamber; And a fuel transport member extending to face the anode electrode. In any embodiment, the communication path is preferably provided at the peripheral edge of the exhaust heat layer farthest from the fuel storage chamber.

The fuel cell [A] of the present invention includes a first intervening layer, which is a hydrophobic porous layer, disposed between the exhaust heat layer and the fuel supply chamber, and a first cover layer covering the opening of the fuel supply chamber. And a second intervening layer that is disposed between the intervening layer and the fuel supply chamber and has a bubble point of 30 kPa or more when the measurement medium is methanol.

The unit cell preferably further includes an anode current collecting layer laminated on the anode electrode and a cathode current collecting layer laminated on the cathode electrode.

The present invention also relates to a fuel cell comprising a unit cell having an anode electrode, an electrolyte membrane, and a cathode electrode in this order, and a fuel supply unit that is disposed on the anode electrode side of the unit cell and supplies fuel to the anode electrode. The fuel supply unit is a space that is open on the anode electrode side, and supplies the fuel so as to cover the fuel supply chamber for circulating or containing the liquid fuel (liquid fuel) and the opening of the fuel supply chamber. And an intervening layer disposed between the chamber and the unit cell, the intervening layer being provided on the fuel supply chamber side in the thickness direction, and a bubble point when the measurement medium is methanol is 30 kPa or more. And a second region that is provided on the unit cell side in the thickness direction and is capable of transmitting vaporized fuel (vaporized fuel).

In the fuel cell [B], the intervening layer is preferably disposed on the fuel supply chamber so as to cover the opening of the fuel supply chamber, and the bubble layer has a bubble point of 30 kPa or more when the measurement medium is methanol, The first layer is laminated on the unit cell side surface and has a two-layer structure including a second layer capable of transmitting vaporized fuel.

The fuel cell [B] of the present invention may further include a third layer having a through-hole penetrating in the thickness direction between the first layer and the second layer. A preferable example of the third layer is a thermoplastic resin sheet having a plurality of through holes penetrating in the thickness direction. Other preferable examples of the third layer include a porous layer formed from an adhesive resin or resin composition, and a metal plate having a plurality of through holes penetrating in the thickness direction. it can.

The unit cell preferably further includes an anode current collecting layer laminated on the anode electrode and a cathode current collecting layer laminated on the cathode electrode. As the fuel, pure methanol or an aqueous methanol solution can be preferably used.

The present invention further provides an electronic device including the fuel cell [A] or [B].

According to the present invention, it is possible to provide a thin fuel cell that can prevent runaway of the internal temperature of the fuel cell and an increase in internal pressure and can maintain stable power generation.

Further, according to the present invention, it is possible to prevent the by-product gas generated at the anode electrode from entering the fuel supply chamber. As a result, a sufficient amount of vaporized fuel can be stably supplied to the anode electrode, so that good output stability can be maintained.

The fuel cell of the present invention is suitable as a small fuel cell for application to a portable electronic device, particularly as a small fuel cell mounted on a portable electronic device.

It is a schematic sectional drawing which shows an example of the fuel cell which concerns on the 1st Embodiment of this invention. FIG. 2 is a schematic top view of the fuel cell shown in FIG. 1. FIG. 3 is a schematic cross-sectional view taken along line III-III shown in FIG. FIG. 4 is a schematic sectional view taken along line IV-IV shown in FIG. 1. FIG. 5 is a schematic sectional view taken along line VV shown in FIG. 1. It is the schematic top view and schematic sectional drawing which show the exhaust heat layer used with the fuel cell shown by FIG. It is the schematic top view and schematic sectional drawing which show the other example of a heat exhaust layer. It is a schematic sectional drawing which shows another example of the fuel cell which concerns on the 1st Embodiment of this invention. It is a schematic sectional drawing which shows another example of the fuel cell which concerns on the 1st Embodiment of this invention. It is a schematic sectional drawing which shows an example of the fuel cell which concerns on the 2nd Embodiment of this invention. FIG. 11 is a schematic top view of the fuel cell shown in FIG. 10. It is a schematic sectional drawing in the III-III line | wire shown by FIG. It is a schematic sectional drawing in the IV-IV line shown by FIG. It is a schematic sectional drawing in the VV line | wire shown by FIG. It is a schematic sectional drawing which shows another example of a fuel supply part. It is a schematic sectional drawing which shows another example of a fuel supply part. It is a schematic sectional drawing which shows another example of the fuel cell which concerns on the 2nd Embodiment of this invention. It is a schematic sectional drawing which shows an example of the fuel cell which concerns on the 3rd Embodiment of this invention. It is a schematic top view which shows the 3rd layer with which the fuel cell shown by FIG. 18 is provided. 2 is a top view showing an exhaust heat layer produced in Example 1. FIG. 3 is a top view showing a box housing (flow path plate) produced in Example 1. FIG. FIG. 4 is a diagram showing IV measurement results of the fuel cell manufactured in Example 1. FIG. 4 is a diagram showing IV measurement results of a fuel cell manufactured in Example 2. It is a figure which shows the output stability of the fuel cell produced in Example 1 and Comparative Example 1. FIG. 6 is a schematic top view showing a first layer of an intervening layer used in Example 3. FIG. 6 is a schematic top view showing a second layer of the intervening layer used in Example 3. FIG. 6 is a schematic top view showing a box housing used in Example 3. FIG. 6 is a schematic top view showing a third layer of the intervening layer used in Example 5. FIG.

Hereinafter, the fuel cell of the present invention will be described in detail with reference to embodiments.
<First Embodiment>
FIG. 1 is a schematic cross-sectional view showing an example of a fuel cell according to the present embodiment, and shows an example of the fuel cell [A]. FIG. 2 is a schematic top view of the fuel cell. In addition, sectional views taken along lines III-III, IV-IV and VV shown in FIG. 1 are shown in FIGS. 3 to 5, respectively. A fuel cell 100 shown in these drawings includes a membrane electrode assembly 20 including an anode electrode 11, an electrolyte membrane 10, and a cathode electrode 12 in this order, and is laminated on the anode electrode 11 and electrically connected thereto. A unit cell 30 comprising an anode current collecting layer 21 and a cathode current collecting layer 22 laminated on and electrically connected to the cathode electrode 12; exhaust heat laminated in contact with the surface of the anode current collecting layer 21 Layer 1; a first intervening layer 2 which is a hydrophobic porous layer laminated in contact with the surface of the exhaust heat layer 1; below the anode 11 (more specifically, below the first intervening layer 2) A fuel supply chamber 60 comprising a space disposed and opened on the anode electrode 11 side; a fuel storage chamber 70 for accommodating (holding) fuel (not shown) supplied to the anode electrode 11; and one end (FIG. 1) Is the fuel storage chamber. Together they are positioned within 0, and the other end is arranged in the fuel supply chamber 60, basically comprises a fuel transport member 61 extending so as to face the anode electrode 11. The fuel transport member 61 is made of a material that exhibits a capillary action on the liquid fuel (liquid fuel) accommodated in the fuel storage chamber 70, and the liquid fuel is brought into the fuel supply chamber 60 by the capillary action of the fuel transport member 61. Distributed. The fuel supply chamber 60, the fuel storage chamber 70, and the fuel transport member 61 constitute a fuel supply unit of the fuel cell 100.

The space immediately below the anode electrode 11 constituting the fuel supply chamber 60 is formed by the box housing 40 and the first intervening layer 2 which are arranged below the unit cell 30 so as to be in contact with the first intervening layer 2. Yes. That is, the box housing 40 has a recess that constitutes the fuel supply chamber 60, and is aligned so that the recess is disposed immediately below the anode 11, and the opening side of the recess is the first intervening layer 2. The fuel supply chamber 60 is formed by disposing the box housing 40 so as to oppose to each other. Further, the box housing 40 has a portion constituting the fuel supply chamber 60 of the fuel cell 100 and a portion constituting the bottom wall and side wall of the fuel storage chamber 70 as an integral unit.

The fuel cell 100 is provided with a box housing 40 and a lid housing 50 that is stacked on the cathode current collecting layer 22 and has a plurality of openings 51, and the unit cell 30 is sandwiched between the box housing 40 and the lid housing 50. ing. The lid housing 50 integrally has a portion constituting the upper wall (ceiling wall) of the fuel storage chamber 70 together with a portion laminated on the cathode current collecting layer 22, and the box housing 40, the lid housing 50, and the unit. A fuel storage chamber 70 is formed by the battery 30. A cured product of the epoxy-based curable resin composition so that the fuel stored in the fuel storage chamber 70 does not enter the end surfaces of the unit cell 30, the exhaust heat layer 1, and the first intervening layer 2 on the fuel storage chamber 70 side. A sealing layer 80 made of a layer or the like is formed. In the fuel cell 100, the fuel storage chamber 70 is disposed on the side of the unit cell 30 and the fuel supply chamber 60 disposed below the unit cell 30.

The box housing 40 includes a first opening 63 connected to the communication path 1b of the heat exhaust layer 1. Further, the fuel storage chamber 70 includes a second opening 71 that communicates the internal space with the outside of the fuel cell 100. The second opening 71 is a through hole provided in the lid housing 50.

The fuel cell 100 generates power by the following operation. That is, when the liquid fuel is supplied to the fuel storage chamber 70, the liquid fuel moves from the end of the fuel transport member 61 on the fuel storage chamber 70 side to the pores of the fuel transport member 61 by capillary action. The moved liquid fuel permeates the fuel transport member 61 through the capillary tube composed of the pores of the fuel transport member 61 and reaches the other end of the fuel transport member 61 (the end opposite to the fuel storage chamber 70 side). Go around.

The liquid fuel that has permeated the fuel transport member 61 and transported into the fuel supply chamber 60 fills the space of the fuel supply chamber 60 in a gas state. The fuel (vaporized fuel) in the gas state passes through the first intervening layer 2 so that the amount or concentration thereof is adjusted to an appropriate range, and the amount or concentration is made uniform. When the vaporized fuel that has passed through the first intervening layer 2 passes through the through-hole 1a of the exhaust heat layer 1, appropriate adjustment and equalization of the amount or concentration thereof is promoted. The vaporized fuel that has passed through the exhaust heat layer 1 is supplied to the anode 11 through the opening of the anode current collecting layer 21. Then, taking a methanol aqueous solution as an example of the liquid fuel, the gaseous methanol aqueous solution supplied to the anode 11 is
CH ₃ OH + H ₂ O → CO ₂ ↑ + 6H ⁺ + 6e ⁻
This causes an oxidation reaction represented by the formula: On the other hand, in the cathode electrode 12, oxygen in the air that has reached through the opening 51 of the lid housing 50 and the opening of the cathode current collecting layer 22, and the oxygen from the anode electrode 11 to the cathode electrode 12 are transmitted through the electrolyte membrane 10. Proton
3 / 2O ₂ + 6H ⁺ + 6e ⁻ → 3H ₂ O
The reduction reaction represented by the formula Through the above oxidation-reduction reaction, electrons move in the route of anode electrode 11 → anode current collecting layer 21 → external electronic device (load) → cathode current collecting layer 22 → cathode electrode 12 to the external electronic device. Power is supplied.

The vaporized fuel in the fuel supply chamber 60 is consumed in accordance with the amount of current consumed by the fuel cell 100. To compensate for this, the liquid fuel continues to evaporate from the fuel transport member 61. The concentration of the vaporized fuel in the supply chamber 60 is kept substantially constant, and sufficiently high power can be stably supplied. Further, since the first intervening layer 2 and the exhaust heat layer 1 are provided between the unit cell 30 and the fuel supply section (more specifically, the fuel supply chamber 60 including the fuel transport member 61), the anode electrode 11 can be supplied uniformly and controlled in an appropriate amount. Thereby, fuel crossover can be effectively suppressed, temperature unevenness hardly occurs in the power generation unit, and a stable power generation state can be maintained. The exhaust heat layer 1 which is one of the features of the present invention will be described in detail later.

In the fuel cell 100 of the present embodiment, the transport of the liquid fuel from the fuel storage chamber 70 to the fuel supply chamber 60 (permeation movement of the liquid fuel in the fuel transport member 61) is exclusively performed through the pores of the fuel transport member 61. It utilizes the capillary phenomenon derived from the above. Therefore, the transportation of the liquid fuel from the fuel storage chamber 70 to the fuel supply chamber 60 can be performed without using external power and substantially not affected by gravity.

Next, each member constituting the fuel cell 100 will be described in detail.
[Exhaust heat layer]
6 (a) is a schematic top view showing the exhaust heat layer 1 used in the fuel cell 100 shown in FIG. 1, and FIG. 6 (b) is a BB ′ line shown in FIG. 6 (a). FIG. As shown in FIG. 6, the fuel cell 100 shown in FIG. 1 is between the unit cell 30 and the fuel supply unit (more specifically, between the unit cell 30 and the first intervening layer 2). A heat exhaust layer 1 having a through hole 1a penetrating in the thickness direction and a communication path 1b communicating the through hole 1a and the outside of the heat exhaust layer 1 is provided. The through-hole 1a also functions as a supply path for the vaporized fuel that has passed through the first intervening layer 2 to the anode electrode 11. In the exhaust heat layer 1 shown in FIG. 6A, the communication path 1b is formed in a groove (concave portion) provided at the peripheral edge of the exhaust heat layer 1 and extending from the through hole 1a to the end surface of the peripheral edge. This peripheral edge is the peripheral edge farthest from the fuel storage chamber 70 among the four peripheral edges (see FIG. 1). However, the position of the communication path 1b is not limited to this position, and may be formed at another peripheral edge.

Providing the exhaust heat layer 1 between the unit cell 30 and the fuel supply unit (fuel supply chamber 60) is advantageous in the following points.
(I) Heat insulation between the power generation unit (membrane electrode assembly 20) of the unit cell 30 and the fuel supply unit can be achieved by the air layer present in the through hole 1a. Thereby, the crossover by the temperature of a fuel supply part rising excessively can be suppressed. This contributes to suppression of runaway battery internal temperature and increase in internal pressure.
(Ii) By-product gas such as CO ₂ gas generated at the anode electrode 11 reaches the through-hole 1a with heat generated by power generation, and then continues to the communication path 1b (in the embodiment shown in FIG. 1). The fuel is discharged outside the fuel cell through the first opening 63). As a result, the amount of heat accumulated in the fuel cell can be greatly reduced, and therefore, an increase in temperature of the entire fuel cell including the fuel supply unit can be suppressed. This also contributes to suppression of battery internal temperature runaway and internal pressure rise. In particular, by providing the exhaust heat layer 1 with the communication path 1b (by-product gas outlet), it is difficult for heat to be transmitted to the fuel supply section. It has a structure that is less prone to crossover and temperature runaway.
(Iii) Since the by-product gas can be discharged well from the communication path 1b, the fuel supply hindrance due to the defective discharge of the by-product gas can be suppressed, and the fuel supply to the anode 11 is good. Thereby, stable power generation characteristics can be obtained. Moreover, since by-product gas can be discharged | emitted favorably from the communication path | route 1b, the penetration | invasion into the fuel supply chamber 60 of by-product gas can be prevented or suppressed. As a result, a sufficient amount of vaporized fuel can be stably supplied to the anode 11, so that the output stability of the fuel cell can be improved.

As described above, in the present invention, the power generation unit and the fuel supply unit are insulated from each other by the air layer of the exhaust heat layer 1, but not only this, but also by the communication path 1 b that connects the through hole 1 a and the outside, In addition to the discharge of raw gas, the heat generated by power generation can be discharged. With such a structure capable of discharging heat, it is not necessary to sufficiently insulate the distance between the power generation unit and the fuel supply unit (that is, the thickness of the exhaust heat layer 1) sufficiently large. Therefore, according to the present invention, the distance between the power generation unit and the fuel supply unit (that is, the thickness of the exhaust heat layer 1) can be reduced, thereby achieving a reduction in the thickness of the fuel cell. The thickness of the heat exhaust layer 1 (and hence the through-hole 1a) can be set to about 100 to 1000 μm, for example, and can be reduced to about 100 to 300 μm. In addition, as above-mentioned, the through-hole 1a is functioning also as a supply path | route to the anode pole 11 of the vaporization fuel which permeate | transmitted the 1st intervening layer 2, and the exhaust heat layer 1 does not have the through-hole 1a. In this case, fuel cannot be supplied to the anode 11 and power generation cannot be performed.

From the viewpoint of heat insulation between the power generation unit and the fuel supply unit, the through-hole 1a of the exhaust heat layer 1 can increase the aperture ratio with respect to the area of the exhaust heat layer 1 as much as possible as shown in FIG. Therefore, it is preferable that the exhaust heat layer 1 has a frame shape (b-shaped) having a through hole 1a as large as possible. The opening ratio of the through-hole 1a, that is, the opening area of the through-hole 1a with respect to the area of the exhaust heat layer 1 (as will be described later, the exhaust heat layer 1 may have two or more through-holes 1a. The ratio of the total area of the openings is preferably 50% or more, more preferably 60% or more. Increasing the aperture ratio of the through-hole 1a is also advantageous for enhancing the function of the exhaust heat layer 1 to make the concentration of the fuel supplied to the anode 11 uniform, and sufficient fuel supply to the anode 11 is achieved. It is advantageous also in securing. In addition, the opening rate of the through-hole 1a is 90% or less normally.

The communication path 1b is not limited to a groove (concave portion) provided in the peripheral edge portion of the exhaust heat layer 1, and may be a through hole penetrating in the thickness direction, but from the viewpoint of the strength of the exhaust heat layer 1 Preferably, the exhaust heat layer 1 includes a groove (concave portion) provided at the peripheral edge. In the case where the communication path 1b is composed of a groove (concave), the depth of the communication path 1b is preferably 50 μm or more. Even when the adjacent member (for example, the anode current collecting layer 21) and the exhaust heat layer 1 are joined by hot pressing (thermocompression) using a thermocompression sheet by setting the depth to 50 μm or more. Further, it is possible to prevent the communication path 1b from being blocked by the thermocompression bonding sheet. Further, from the viewpoint of the strength of the exhaust heat layer 1, the depth of the communication path 1 b is preferably up to about 75% of the thickness of the exhaust heat layer 1.

FIG. 7A is a schematic top view showing another example of the exhaust heat layer, and FIG. 7B is a schematic cross-sectional view taken along line C-C ′ shown in FIG. 7A. As shown in FIG. 7, the exhaust heat layer 1 may have two or more through-holes 1a. In the example of FIG. 7, the exhaust heat layer 1 has a total of four through holes 1 a arranged in two rows. It can also be said that beams are provided in the vertical direction and the horizontal direction of a large through hole and divided into four. Since the exhaust heat layer 1 having a plurality of through-holes 1a (provided with beams) has improved rigidity in the in-plane direction of the exhaust heat layer 1, a fuel cell excellent in strength against impact or the like can be obtained. Is advantageous. In addition, in comparison with a structure in which no beam is provided as shown in FIG. 6, the through-hole 1 a is less likely to be blocked due to expansion or the like due to heat or the like of members disposed above and below the exhaust heat layer 1. Is also advantageous.

When the exhaust heat layer 1 has two or more through-holes 1a, the communication path 1b provided in the peripheral portion of the exhaust heat layer 1 and connecting the through-hole 1a and the outside of the exhaust heat layer 1 is provided for each through-hole 1a. The same number as the number of through-holes 1a may be provided, or the number of communication paths 1b that is smaller or larger than the number of through-holes 1a may be provided. In the example of FIG. 7, the two communication paths 1 b are provided only for the peripheral part farthest from the fuel storage chamber 70 with respect to the four through holes 1 a. Thus, although it is not necessary to provide the communication path 1b for every through-hole 1a, in that case, as shown in FIG. 7, in the through-hole in which the communication path 1b is not provided (in FIG. 7A). The lower two through holes 1a) are spatially connected by a connection path 1c to the through holes provided with the communication path 1b (the upper two through holes 1a in FIG. 7A). Similarly to the communication path 1b, the connection path 1c can be a groove (concave part) provided in the beam between the through-holes 1a (see FIG. 7B). By providing the connection path 1c, the by-product gas that has entered the through hole where the communication path 1b is not provided can be discharged to the outside through the communication path 1b.

In order to improve the efficiency of discharging the by-product gas that has reached the through-hole 1a of the exhaust heat layer 1 to the outside, or to make the concentration of the fuel supplied to the anode electrode 11 of the exhaust heat layer 1 uniform. In order to increase, it is also preferable to provide a connection path 1d that spatially connects the through holes provided with the communication path 1b and / or the through holes not provided with the communication path 1b.

The shape (width and length, etc.) of the plurality of through-holes 1a, the number of arrangements (in other words, the number of beams provided vertically and horizontally, the arrangement interval, etc.) are the positions of the recesses forming the fuel supply chamber 60 in the box housing 40. It is preferable to determine the number, the number, and the arrangement interval in the case of having a plurality of recesses. For example, the production of the fuel cell preferably includes a step of joining the exhaust heat layer 1 (or the laminate of the exhaust heat layer 1 and the first intervening layer 2) and the box housing 40 by hot pressing (thermocompression bonding). However, in order to obtain good bondability (bonding area) between these members, pressure cannot be applied to the recesses forming the fuel supply chamber 60 in the box housing 40, so It is preferable to adjust the shape of the heat exhaust layer 1 (or the shape of the box housing 40) so that the beam of the heat exhaust layer 1 which is a portion to which pressure is applied is not disposed.

The communication path 1b may be provided in any one of the four peripheral portions, but the anode is used when the fuel storage chamber 70 is disposed on the side of the unit cell 30 as in the example shown in FIG. In the case where a gradient occurs in the amount of fuel supplied in the surface of the pole 11, it is preferable that at least one of the communication paths 1b is provided at the peripheral edge farthest from the fuel storage chamber 70 from the viewpoint of improving fuel utilization efficiency. It is more preferable to provide all of the paths 1b at the peripheral edge farthest from the fuel storage chamber 70. That is, when the communication path 1b is provided at such a position, the amount of fuel discharged from the communication path 1b can be reduced as much as possible.

Further, when the fuel cell has a stack structure including a plurality of unit cells arranged in a row on the same plane, adjacent units are prevented so that air supply to the adjacent unit cells is not hindered by by-product gas discharge. It is preferable to provide the communication path 1b in the peripheral part which does not face a battery. For example, when stacking unit cells by arranging a plurality of unit cells in a row, the fuel storage chamber 70 is disposed along one of two peripheral portions of the stack structure that do not face adjacent unit cells. All the communication paths 1b can be provided in the other peripheral edge (that is, the peripheral edge farthest from the fuel storage chamber 70). Thereby, obstruction of the air supply to the unit battery can be prevented, and the amount of fuel discharged from the communication path 1b can be reduced as much as possible.

The ratio S ₁ / S ₀ between the cross-sectional area of the communication path 1b (the sum of these cross-sectional areas when two or more communication paths 1b are provided) S ₁ and the total area S ₀ of the side surface of the exhaust heat layer 1 is In order to discharge the by-product gas and the heat accompanying it, it is necessary to make it larger than 0, preferably 0.002 or more. Further, it is preferably less than 0.3, more preferably less than 0.1, and still more preferably less than 0.05. When the ratio is 0.3 or more, fuel leakage or air mixing is likely to occur, and power generation stability may be reduced.

For example, when all of the communication paths 1b are provided at the peripheral edge farthest from the fuel storage chamber 70, one or two or more communication paths 1b are provided only at one of the four peripheral edges of the exhaust heat layer 1. in case of providing the (sum of these cross-sectional area in the case of having two or more communicating path 1b) cross-sectional area of the communicating path 1b and S _1, the cross-sectional area S ₂ of the side surface at the peripheral portion communicating path 1b is provided The ratio S ₁ / S ₂ is preferably 0.008 or more for the same reason as described above.

The material of the exhaust heat layer 1 can be plastic, metal, non-porous carbon material or the like. Examples of the plastic include polyphenylene sulfide (PPS), polyimide (PI), polymethyl methacrylate (PMMA), acrylonitrile butadiene styrene (ABS), polyvinyl chloride, polyethylene (PE), polyethylene terephthalate (PET), and polyether. Examples include ether ketone (PEEK), polytetrafluoroethylene (PTFE), and polyvinylidene fluoride (PVDF). As the metal, for example, alloys such as stainless steel and magnesium alloy can be used in addition to titanium and aluminum. From the viewpoint of further improving the heat insulation between the power generation unit and the fuel supply unit, it is preferable to use a material having low thermal conductivity for the exhaust heat layer 1, but the heat insulation by the exhaust heat layer 1 is the heat of the material. The contribution of the air layer formed in the through-hole 1a is greater than the conductivity. Therefore, in terms of heat insulation, it is more important to consider the volume of the air layer (opening ratio and thickness of the through hole 1a) than the material of the exhaust heat layer 1.

Among the above, the exhaust heat layer 1 is preferably made of a material having high rigidity such as metal, polyphenylene sulfide (PPS), or polyimide (PI). When the exhaust heat layer 1 having high rigidity is used, the unit cell 30, the exhaust heat layer 1, and the fuel supply unit can be joined by hot pressing (thermocompression bonding), thereby reducing variations in fuel cell thickness and power generation characteristics. can do. Further, it is possible to effectively prevent the communication path 1b from being blocked during hot pressing.

[First intervening layer]
The first intervening layer 2 is a porous layer that is disposed between the exhaust heat layer 1 and the fuel supply unit and has a hydrophobic property of vaporized fuel permeability and liquid fuel impermeability, and is a fuel to the anode 11. It is a layer (gas-liquid separation layer) that enables vaporization and supply. The first intervening layer 2 preferably has a function of controlling (limiting) the amount or concentration of vaporized fuel supplied to the anode 11 to an appropriate amount and making it uniform. By providing the first intervening layer 2, fuel crossover can be effectively suppressed, temperature unevenness hardly occurs in the power generation unit, and a stable power generation state can be maintained. Further, since the first intervening layer 2 has hydrophobicity, water to the fuel supply unit side (for example, water generated at the cathode electrode 12 and moved to the anode electrode 11 side through the electrolyte membrane 10). Can be prevented from entering. As a result, the water concentration in the anode 11 is kept good, so that a decrease in output can be prevented. This effect is particularly advantageous when a high concentration fuel (pure methanol or the like) is used.

The first intervening layer 2 is not particularly limited as long as it has gas-liquid separation ability with respect to the fuel to be used. For example, fluororesin such as polytetrafluoroethylene (PTFE) and polyvinylidene fluoride, water repellent Examples thereof include a porous film or a porous sheet made of a treated silicone resin, and specifically, a TEMISH (TEMISH (registered trademark)) manufactured by Nitto Denko Corporation, which is a porous film made of polytetrafluoroethylene. ] “NTF2026A-N06” and “NTF2122A-S06”. The thickness of the first intervening layer 2 is not particularly limited, but is preferably 20 μm or more and more preferably 50 μm or more in order to sufficiently express the above function. From the viewpoint of reducing the thickness of the fuel cell, the thickness of the first intervening layer 2 is preferably 500 μm or less, and more preferably 300 μm or less. In the present embodiment, the first intervening layer 2 may be omitted, but the first intervening layer 2 is disposed between the exhaust heat layer 1 and the fuel supply unit from the viewpoint of suppressing crossover. It is preferable.

[Fuel transport member]
The fuel transport member 61 is a member that is disposed at least in part in the fuel supply chamber 60 and transports liquid fuel from the fuel storage chamber 70 to the fuel supply chamber 60 by utilizing capillary action. It consists of the material which shows a capillary action with respect to. Examples of such a material having a capillary action include acrylic resins, ABS resins, polyvinyl chloride, polyethylene, polyethylene terephthalate, polyether ether ketone, polytetrafluoroethylene and other fluorine-based resins, and cellulose polymer materials. And a porous body having irregular pores made of a metal material such as stainless steel, titanium, tungsten, nickel, aluminum, and steel. As a porous body, the nonwoven fabric which consists of the said metal material, a foam, a sintered compact, the nonwoven fabric which consists of the said polymeric material, etc. can be mentioned. Further, a plate-like body made of the above polymer material or metal material and having a regular or irregular slit pattern (groove pattern) on the surface as a capillary tube can be used as the fuel transport member 61.

The pore diameter of the pores of the fuel transport member 61 is such that a sufficient capillary action with respect to gravity occurs, and a good suction height (the liquid fuel due to the capillary action when one end of the fuel transport member is immersed in the liquid fuel) In order to obtain a reachable position in the member) and a suction speed (meaning the volume of liquid fuel sucked up per unit time when one end of the fuel transport member is immersed in liquid fuel) The thickness is preferably 500 μm, more preferably 1 to 300 μm. The pore diameter of the pores of the fuel transport member 61 is a diameter measured by a mercury intrusion method. If the suction height is too small, liquid fuel cannot be supplied over the entire anode electrode, and the output of the fuel cell can be reduced. Further, if the suction speed is not sufficient for the consumption speed of the liquid fuel consumed by the power generation by the fuel cell, the liquid fuel is depleted in any part of the fuel transport member 61, and the fuel transport member 61. As a result of not supplying the liquid fuel to the other end of the fuel cell, the output of the fuel cell can similarly decrease.

The porous body (metal porous body) made of the metal material will be described in detail. Among the metal porous bodies, a metal porous body made of a metal material such as stainless steel, titanium, tungsten, nickel, aluminum, or steel is preferable. More preferably, a metal fiber nonwoven fabric obtained by processing the metal material into a fiber and forming a nonwoven fabric, or a metal fiber nonwoven fabric sintered body obtained by sintering and rolling the metal material as necessary, More preferably, it is used. By using the metal fiber nonwoven fabric sintered body, sufficient strength of the fuel transport member 61 can be maintained even when the porosity is increased, so that the assembly accuracy at the time of manufacturing the fuel cell can be increased. In addition, since the porosity can be increased while maintaining sufficient strength, the amount of liquid fuel that can be held by the fuel transport member 61 can be improved. This means that when the suction height is the same, the suction speed becomes larger. Therefore, the liquid fuel is effectively supplied also to the portion of the anode electrode 11 away from the fuel storage chamber 70. It becomes possible to do.

As a material showing the capillary action constituting the fuel transport member 61, it is preferable to use a material having a pumping distance after 30 minutes of 10 cm or more, and a material having a capacity of 15 cm or more from the viewpoint of the suction height and the suction speed. It is more preferable. As such, there are “Pigeon sheet” manufactured by Oji Kinocross Co., Ltd., “Water guide sheet” manufactured by Toray Industries, Inc., and the like. The pumping distance means the arrival height of the water after leaving the felt test piece 2 cm under water at a temperature of 25 ° C. and leaving it for a certain time (30 minutes).

In the fuel cell 100 shown in FIG. 1, the fuel transport member 61 has a strip shape, more specifically, a rectangular parallelepiped shape (see FIGS. 1 and 4). However, the shape of the fuel transport member 61 is not limited to such a shape. The shape of the fuel transport member 61 may be an appropriate shape according to the shape of the entire fuel cell, the shape of the membrane electrode assembly 20, the shape of the fuel supply chamber 60, or the like. can do. As other examples other than a rectangular parallelepiped shape, for example, a cubic shape, a strip shape such as a shape whose width decreases or increases continuously or stepwise from one end to the other end (a shape whose surface is a trapezoid or a triangle, etc.) Can be mentioned.

The length of the fuel transport member 61 (distance from one end on the fuel storage chamber 70 side to the other end facing this) is not particularly limited, and the shape of the entire fuel cell, the shape of the membrane electrode assembly 20, or the fuel supply chamber 60 is not limited. However, when one end of the fuel transport member 61 is disposed at a position where it can contact the liquid fuel held in the fuel storage chamber 70, the other end is the anode 11. It is preferable that it has a length such that it is arranged at a position almost immediately below the end (the end opposite to the fuel storage chamber 70 side) or longer. Thereby, fuel can be supplied more effectively over the entire anode electrode 11 including the end of the anode electrode 11 opposite to the fuel storage chamber 70 side.

As shown in FIG. 1, the “position where the liquid fuel can be contacted” refers to the case where one end of the fuel transport member 61 is located inside the fuel storage chamber 70 as well as the one end of the fuel transport member 61 is supplied with fuel. This includes a case where the chamber 60 and the fuel storage chamber 70 are located inside a wall (which is a part of the box housing 40). By adjusting the length of the fuel transport member 61 so that one end of the fuel transport member 61 is positioned inside the fuel storage chamber 70, liquid fuel can be used regardless of the orientation of the fuel cell 100 in use. And the fuel transport member 61 can be contacted.

The thickness of the fuel transport member 61 is not particularly limited, and is appropriately determined according to the thickness of the fuel cell 100, the height of the fuel supply chamber 60, and the like. For example, the thickness can be about 0.05 to 5 mm. From the viewpoints of reducing the thickness and improving the siphoning height and the siphoning speed, the thickness is preferably 0.1 to 1 mm.

The fuel transport member 61 having a strip shape in the fuel cell 100 shown in FIG. 1 is disposed so as to face the anode electrode 11 at a position immediately below the unit cell 30 having a strip shape (more specifically, a rectangular parallelepiped shape). Has been. More specifically, the fuel transport member 61 is disposed at a position immediately below the anode electrode 11 through the anode current collecting layer 21, the exhaust heat layer 1, the hydrophobic porous layer 2, and the upper space of the fuel supply chamber 60. The anode 11 and the fuel transport member 61 are arranged in the vertical direction (stacking direction of each member of the fuel cell) (see FIG. 1) and the direction perpendicular thereto (width direction of the fuel cell). (See FIG. 5), both are parallel. Such an arrangement relationship between the anode 11 and the fuel transport member 61 is extremely preferable for efficiently supplying fuel from the fuel transport member 61 to the anode 11, but is not limited to such an arrangement. Absent. For example, the fuel transport member 61 can be disposed so as to be inclined with respect to the vertical direction so as to gradually approach or separate from the anode electrode 11 as the fuel transport member 61 is separated from the fuel storage chamber 70. Further, the fuel transport member 61 may be disposed so as to intersect the anode 11 when the fuel cell 100 is viewed from above. Furthermore, the fuel transport member 61 is not disposed at a position immediately below the anode electrode 11 (so that the position of the fuel transport member 61 and the position of the anode electrode 11 coincide with each other when the fuel cell 100 is viewed from above). It may be arranged in a shifted state.

Further, in the fuel cell 100 shown in FIG. 1, the fuel transport member 61 is disposed in the vicinity of the center in the vertical direction in the fuel supply chamber 60, but is not limited to this, for example, the center in the vertical direction It may be arranged at a place other than the vicinity of the part, may be arranged so as to be in contact with the first intervening layer 2 (or the exhaust heat layer 1), or may be in contact with the bottom surface (box housing 40) of the fuel supply chamber 60. You may arrange as follows.

[Electrolyte membrane]
The electrolyte membrane 10 constituting the membrane electrode assembly 20 has a function of transmitting protons from the anode electrode 11 to the cathode electrode 12, and a function of maintaining electrical insulation between the anode electrode 11 and the cathode electrode 12 and preventing a short circuit. Have. The material of the electrolyte membrane 10 is not particularly limited as long as it is a material having proton conductivity and electrical insulation, and a polymer membrane, an inorganic membrane, or a composite membrane can be used. As the polymer membrane, for example, Nafion (registered trademark, manufactured by DuPont), Aciplex (registered trademark, manufactured by Asahi Kasei), Flemion (registered trademark, manufactured by Asahi Glass Co., Ltd.), which is a perfluorosulfonic acid electrolyte membrane, etc. Can be mentioned. Also, styrene-based graft polymer, trifluorostyrene derivative copolymer, sulfonated polyarylene ether, sulfonated polyetheretherketone, sulfonated polyimide, sulfonated polybenzimidazole, phosphonated polybenzimidazole, sulfonated polyphosphazene. Hydrocarbon electrolyte membranes such as can also be used.

Examples of the inorganic film include films made of glass phosphate, cesium hydrogen sulfate, polytungstophosphoric acid, ammonium polyphosphate, and the like. Examples of the composite film include a composite film of an inorganic material such as tungstic acid, cesium hydrogen sulfate, and polytungstophosphoric acid and an organic material such as polyimide, polyetheretherketone, and perfluorosulfonic acid.

The thickness of the electrolyte membrane 10 is, for example, 1 to 200 μm. The EW value (dry weight per mole of proton functional groups) of the electrolyte membrane 10 is preferably about 800 to 1100. The smaller the EW value, the lower the resistance of the electrolyte membrane 10 accompanying proton transfer, and a higher output can be obtained.

[Anode and cathode]
The anode electrode 11 laminated on one surface of the electrolyte membrane 10 and the cathode electrode 12 laminated on the other surface are provided with a catalyst layer composed of a porous layer having at least a catalyst and an electrolyte. The catalyst for the anode 11 catalyzes a reaction for generating protons and electrons from a liquid fuel such as an aqueous methanol solution, and the electrolyte has a function of conducting the generated protons to the electrolyte membrane 10. The catalyst for the cathode electrode 12 catalyzes a reaction for generating water from protons conducted through the electrolyte and oxygen in the air.

The catalyst for the anode electrode 11 and the cathode electrode 12 may be supported on the surface of a conductor such as carbon or titanium, and in particular, carbon or titanium having a hydrophilic functional group such as a hydroxyl group or a carboxyl group. It is preferably carried on the surface of the conductor. Thereby, the water retention of the anode electrode 11 and the cathode electrode 12 can be improved. In addition, the electrolyte of the anode electrode 11 and the cathode electrode 12 is preferably made of a material having an EW value smaller than that of the electrolyte membrane 10. Specifically, the electrolyte material has the same EW value as the electrolyte membrane 10. An electrolyte material having a 400 to 800 is preferable. By using such an electrolyte material, the water retention of the anode 11 and the cathode 12 can be improved. By improving the water retention of the anode electrode 11 and the cathode electrode 12, the resistance of the electrolyte membrane 10 accompanying the proton transfer and the potential distribution in the anode electrode 11 and the cathode electrode 12 can be improved. In addition, since the electrolyte with a low EW value has a high liquid fuel permeability, vaporized fuel can be uniformly supplied to the catalyst layer of the anode 11 by using an electrolyte with a low EW value.

The anode electrode 11 and the cathode electrode 12 may each include an anode conductive porous layer and a cathode conductive porous layer laminated on the catalyst layer. These conductive porous layers have a function of diffusing gas (vaporized fuel or air) supplied to the anode electrode 11 and the cathode electrode 12 in the plane, and a function of exchanging electrons with the catalyst layer. As the anode conductive porous layer and the cathode conductive porous layer, since the specific resistance is small and the decrease in voltage is suppressed, carbon materials; conductive polymers; noble metals such as Au, Pt, Pd; Ti, Porous materials comprising transition metals such as Ta, W, Nb, Ni, Al, Cu, Ag, Zn; nitrides or carbides of these metals; and alloys containing these metals typified by stainless steel Is preferably used. In the case of using a metal having poor corrosion resistance in an acidic atmosphere, such as Cu, Ag, Zn, etc., noble metals having resistance to corrosion such as Au, Pt, Pd, conductive polymers, conductive nitrides, conductive Surface treatment (film formation) may be performed with carbide, conductive oxide, or the like. More specifically, as the anode conductive porous layer and the cathode conductive porous layer, for example, foam metal, metal fabric and metal sintered body made of the above-mentioned noble metal, transition metal or alloy; and carbon paper, carbon cloth, An epoxy resin film containing carbon particles can be suitably used.

[Anode current collecting layer and cathode current collecting layer]
The anode current collecting layer 21 and the cathode current collecting layer 22 are laminated on the anode electrode 11 and the cathode electrode 12, respectively, and constitute a unit cell 30 together with the membrane electrode assembly 20. The anode current collecting layer 21 and the cathode current collecting layer 22 each have a function of collecting electrons in the anode electrode 11 and the cathode electrode 12 and a function of performing electrical wiring. The material of the current collecting layer is preferably a metal because it has a small specific resistance and suppresses a decrease in voltage even when a current is taken in the plane direction. In particular, it has electron conductivity and has an acidic atmosphere. More preferably, the metal has corrosion resistance. Such metals include noble metals such as Au, Pt, Pd; transition metals such as Ti, Ta, W, Nb, Ni, Al, Cu, Ag, Zn; and nitrides or carbides of these metals; and And alloys containing these metals typified by stainless steel. In the case of using a metal having poor corrosion resistance in an acidic atmosphere, such as Cu, Ag, Zn, etc., noble metals having resistance to corrosion such as Au, Pt, Pd, conductive polymers, conductive nitrides, conductive Surface treatment (film formation) may be performed with carbide, conductive oxide, or the like. When the anode conductive porous layer and the cathode conductive porous layer are made of, for example, metal and the conductivity is relatively high, the anode current collecting layer and the cathode current collecting layer may be omitted.

More specifically, the anode current collecting layer 21 has a mesh shape or a punching metal shape including a plurality of through holes (openings) penetrating in the thickness direction for guiding the vaporized fuel to the anode electrode 11 and made of the above metal material or the like. It can be a flat plate. This through-hole also functions as a discharge hole for guiding by-product gas (CO ₂ gas or the like) generated in the catalyst layer of the anode electrode 11 to the through-hole 1a of the exhaust heat layer 1. Similarly, the cathode current collecting layer 22 has a mesh shape made of the above metal material or the like having a plurality of through holes (openings) penetrating in the thickness direction for supplying air outside the fuel cell to the catalyst layer of the cathode electrode 12. It can be a flat plate having a punching metal shape.

[Fuel supply chamber]
The fuel supply chamber 60, together with the fuel transport member 61 and the fuel storage chamber 70 described later, is a part constituting a fuel supply portion that plays a role of fuel storage and fuel supply, and is preferably disposed immediately below the anode electrode 11, The fuel transport member 61 described above is provided in the internal space. In one preferred embodiment (for example, the fuel cell 100 of FIG. 1), the internal space of the fuel supply chamber 60 is the same as the length from the end of the anode 11 on the fuel storage chamber 70 side to the opposite end thereof. Or it has the length beyond it, and has the width | variety equal to or more than the width | variety of the anode pole 11. FIG. The height (depth) of the internal space of the fuel supply chamber 60 is not particularly limited as long as it has a height that can accommodate the fuel transport member 61.

In the fuel cell 100 shown in FIG. 1, the fuel supply chamber 60 is a box housing having a recess that constitutes the internal space of the fuel supply chamber 60 and is disposed below the unit cell 30 so as to be in contact with the first intervening layer 2. 40 and the first intervening layer 2. The box housing 40 shown in FIG. 1 integrally has a portion constituting the fuel supply chamber 60 and a portion constituting the bottom wall and side wall of the fuel storage chamber 70, but is not limited thereto. Instead, the member constituting the fuel supply chamber 60 and the member constituting the fuel storage chamber 70 may be different members.

The box housing 40 can be manufactured by using a plastic material or a metal material and molding it into an appropriate shape so as to have at least a recess that constitutes the internal space of the fuel supply chamber 60. Examples of plastic materials include polyphenylene sulfide (PPS), polymethyl methacrylate (PMMA), acrylonitrile butadiene styrene (ABS), polyvinyl chloride, polyethylene (PE), polyethylene terephthalate (PET), and polyether ether ketone (PEEK). ), Polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and the like. As the metal material, for example, alloy materials such as stainless steel and magnesium alloy can be used in addition to titanium and aluminum. Among these, polyphenylene sulfide (PPS) and polyethylene (PE) are preferably used because they have high strength and can be processed inexpensively due to an increase in molecular weight due to three-dimensional crosslinking, and are lightweight.

In the fuel cell 100 shown in FIG. 1, the box housing 40 is a first for discharging by-product gas (CO ₂ or the like) accompanied by heat discharged from the communication path 1 b of the exhaust heat layer 1 to the outside of the fuel cell 100. An opening 63 is provided. The first opening 63 is a through hole provided in the side wall of the box housing 40. In order to suppress or prevent the fuel from being discharged from the first opening 63, a porous layer containing a catalyst for burning the fuel may be formed in the first opening 63. Due to the communication path 1b and the first opening 63 provided in the exhaust heat layer 1, the pressure in the fuel supply chamber 60 is maintained at atmospheric pressure without causing an increase in pressure even during operation of the fuel cell. Accordingly, it is possible to prevent the suction height and the suction speed of the fuel transport member 61 from being lowered.

[Fuel storage room]
The fuel storage chamber 70 is a chamber for accommodating (holding) liquid fuel, which is preferably disposed on the side of the unit cell 30 and the fuel supply chamber 60. The size and shape of the fuel storage chamber 70 are not particularly limited, but the one end of the fuel transport member 61 arranged in the fuel supply chamber 60 and the liquid fuel accommodated in the fuel storage chamber 70 can be brought into contact with each other. It is necessary to have an opening on the side wall surface. The opening may be formed from a hole penetrating a wall constituting a part of the box housing 40 that partitions the fuel supply chamber 60 and the fuel storage chamber 70. In this case, the fuel transport member 61 It can be inserted into the hole so that one end is located inside the hole or inside the fuel storage chamber 70 (FIG. 1).

In the fuel cell 100 shown in FIG. 1, the fuel storage chamber 70 is laminated on the cathode current collecting layer 22 and has a lid housing 50, a box housing 40, a unit cell 30, an exhaust heat layer 1, and a first layer. The intervening layer 2 is formed. The end surfaces of the unit cell 30, the exhaust heat layer 1 and the first intervening layer 2 on the fuel storage chamber 70 side are cured products of an epoxy curable resin composition so that the fuel stored in the fuel storage chamber 70 does not enter. It is sealed by a sealing layer 80 made of The fuel storage chamber 70 does not necessarily need to be configured using the lid housing 50 and the box housing 40. For example, the fuel storage chamber 70 has a portion that forms an upper wall (ceiling wall), a side wall, and a bottom wall. It can also be comprised from one member included as one.

In the fuel cell 100 shown in FIG. 1, the lid housing 50 functions as a protective plate that forms the upper wall (ceiling wall) of the fuel storage chamber 70 and prevents the unit cell 30 from being directly exposed. A plurality of openings 51 (however, the number of openings may be one or more) for allowing air to flow are formed in a portion immediately above the cathode electrode 12 of the lid housing 50.

The lid housing 50 can be manufactured by using a plastic material or a metal material and molding it into an appropriate shape. Examples of the plastic material include polyphenylene sulfide (PPS), polymethyl methacrylate (PMMA), acrylonitrile butadiene styrene (ABS), polyvinyl chloride, polyethylene (PE), polyethylene terephthalate (PET), polyether ether ketone (PEEK). ), Polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and the like. As the metal material, for example, alloy materials such as stainless steel and magnesium alloy can be used in addition to titanium and aluminum. Among these, polyphenylene sulfide (PPS) and polyethylene (PE) are preferably used because they have high strength and can be processed inexpensively due to an increase in molecular weight due to three-dimensional crosslinking, and are lightweight.

The fuel storage chamber 70 preferably includes a second opening 71 that communicates the internal space with the outside of the fuel cell. Thereby, even when the liquid fuel is transported to the fuel supply chamber 60 by the fuel transport member 61, the fuel storage chamber 70 is maintained at atmospheric pressure, so that the transport of the liquid fuel is not hindered, and the fuel transport member 61. High wicking height and wicking speed can be maintained. In the fuel cell 100 shown in FIG. 1, the second opening 71 is a through hole that penetrates the lid housing 50 in the thickness direction, but is not limited thereto.

In order to prevent liquid fuel from leaking from the second opening 71, the opening diameter of the second opening 71 is preferably sufficiently small (for example, a diameter of about 100 to 500 μm, preferably 100 to 300 μm), or And providing a gas-liquid separation membrane (for example, a porous membrane made of polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, or the like) in the second opening 71 for preventing leakage of liquid fuel to the outside of the fuel cell. Is preferred.

[Other components]
The fuel cell 100 of the present embodiment may further include a second interposed layer disposed between the first interposed layer 2 and the fuel supply chamber 60. In this case, the second intervening layer covers the opening of the fuel supply chamber 60 (the open surface toward the anode electrode 11) (that is, covers the recess forming the fuel supply chamber 60). The first intervening layer 2 is laminated on the second intervening layer. The second intervening layer is a layer having a bubble point of 30 kPa or more when the measurement medium is methanol. By arranging such a second intervening layer so as to cover the opening of the fuel supply chamber 60, Since liquid fuel is held in the pores of the two intervening layers by a capillary force, the by-product gas (such as CO ₂ gas) generated in the anode 11 is effectively prevented from entering the fuel supply chamber 60. be able to.

Here, the bubble point is the minimum pressure at which bubbles are observed on the surface of the layer (film) when air pressure is applied from the back side of the layer (film) wetted with the liquid medium. The higher the bubble point, the lower the gas permeability. The bubble point ΔP is expressed by the following formula (1):
ΔP [Pa] = 4γcos θ / d (1)
(Γ is the surface tension [N / m] of the measurement medium, θ is the contact angle between the material of the layer (film) and the measurement medium, and d is the maximum pore diameter of the layer (film)).
Defined by In the present invention, the bubble point is measured according to JIS K3832, using methanol as the measurement medium.

From the viewpoint of effectively preventing the by-product gas from entering the fuel supply chamber 60, the bubble point of the second intervening layer is preferably 50 kPa or more, and more preferably 100 kPa or more. As understood from the above (1), the bubble point of the second intervening layer can be controlled by adjusting the pore diameter and the contact angle of the material used as the second intervening layer.

In order to achieve a bubble point of 30 kPa or more, the maximum pore diameter of the pores of the second intervening layer is preferably 1 μm or less, and more preferably 0.7 μm or less. The maximum pore diameter can be obtained by measuring the bubble point, but can be measured by mercury porosimetry as another method. However, since the mercury intrusion method can measure only a pore distribution of 0.005 μm to 500 μm, it is an effective measuring means when pores outside this range do not exist or can be ignored.

Examples of the second intervening layer include a porous layer made of a polymer material, a metal material, or an inorganic material, and a polymer film. Specific examples are as follows.

1) A porous layer made of the following materials. Fluorine resins such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE); acrylic resins; ABS resins; polyolefin resins such as polyethylene and polypropylene; polyester resins such as polyethylene terephthalate; cellulose acetate and nitrocellulose Cellulose resins such as ion exchange cellulose; Nylon; Polycarbonate resins; Chlorine resins such as polyvinyl chloride; Polyetheretherketone; Polyethersulfone; Glass; Ceramics; Stainless steel, titanium, tungsten, nickel, aluminum, steel, etc. Metal material. The porous layer can be a foam, a sintered body, a nonwoven fabric or a fiber (such as glass fiber) made of these materials.

2) A polymer film made of the following materials. Perfluorosulfonic acid polymer; styrene graft polymer, trifluorostyrene derivative copolymer, sulfonated polyarylene ether, sulfonated polyetheretherketone, sulfonated polyimide, sulfonated polybenzimidazole, phosphonated polybenzimidazole Those that can be used as electrolyte membrane materials such as hydrocarbon polymers such as sulfonated polyphosphazene. These polymer films have nano-order pores as gaps between polymers that are three-dimensionally entangled.

When a polymer material is used as the material constituting the second intervening layer, hydrophilization is performed by a method such as introduction of a hydrophilic functional group, and water on the pore surface (thus, fuel such as methanol or methanol aqueous solution). ), The bubble point of the second intervening layer can be increased. In addition, by applying a hydrophilic treatment to the second intervening layer, the liquid fuel can be circulated in the fuel supply chamber 60 with a lower pressure loss.

The thickness of the second intervening layer is not particularly limited, but is preferably 20 to 500 μm, more preferably 50 to 200 μm from the viewpoint of reducing the thickness of the fuel cell.

The fuel cell according to the present embodiment including the second intervening layer has the following advantages.
(A) By disposing the second intervening layer having a bubble point of 30 kPa or more between the exhaust heat layer 1 and the fuel supply chamber 60, the by-product gas generated in the anode 11 is generated in the fuel supply chamber 60. Can be prevented from entering. This means that the discharge route of the by-product gas to the outside of the fuel cell is restricted to the discharge route from the communication path 1b of the exhaust heat layer 1, and therefore the by-product gas from the communication path 1b It is possible to promote the discharge and the heat discharge associated therewith, and to more effectively suppress the transfer of heat to the fuel supply unit. As a result, it is possible to more effectively suppress an excessive temperature rise as a whole fuel cell including the fuel supply unit, and crossover and temperature runaway associated therewith.

(B) The intrusion of the by-product gas into the fuel supply chamber 60 reduces the amount of vaporized fuel supplied to the anode 11 and inhibits the stable supply of vaporized fuel, thereby reducing the output stability of the fuel cell. Reduce. Providing the second intervening layer prevents the by-product gas from entering the fuel supply chamber 60, so that a sufficient amount of vaporized fuel can be stably supplied to the anode 11. Therefore, the output stability of the fuel cell can be improved. In addition, it is possible to more effectively suppress peeling at the interface between the constituent members and destruction of the constituent members due to the by-product gas entering and the internal pressure of the fuel supply chamber 60 increasing, thereby further improving the reliability of the fuel cell. Can be made.

(C) As will be described later, in the fuel cell of the present embodiment, the fuel supply unit includes a fuel storage chamber 70 that stores liquid fuel and a fuel supply chamber 60 that circulates the fuel, and the fuel transport member 61 is omitted. Is possible. In this case, the second intervening layer may provide a capillary force for transporting the liquid fuel in the fuel storage chamber 70 into the fuel supply chamber 60. Therefore, when the second intervening layer is provided, the liquid fuel can be passively supplied (fuel supply without using an auxiliary device such as a pump) even when the above-described fuel transport member 61 is not used. However, the second intervening layer and the fuel transport member 61 can be provided side by side.

In addition, since the 1st intervening layer 2 has vaporization fuel permeability, it has a bubble point smaller than a 2nd intervening layer. The bubble point according to the measurement method of the first intervening layer 2 is preferably 10 kPa or less, and the larger the contact angle of methanol with respect to the first intervening layer 2, the better, preferably 45 degrees or more, more preferably 90 degrees. More than about. Further, from the viewpoint of imparting vaporized fuel permeability and liquid fuel impermeability, the maximum pore diameter of the pores of the first intervening layer 2 is preferably 0.1 to 10 μm, preferably 0.5 to 5 μm. It is more preferable that The maximum pore diameter of the pores of the first intervening layer 2 can be determined by measuring bubble points using methanol or the like, as in the second intervening layer.

In addition, the fuel cell according to the present embodiment can include a pumping unit such as a pump for pumping the liquid fuel accommodated in the fuel storage chamber 70 to the fuel supply chamber 60.

The fuel cell according to the present embodiment including the pressure feeding means has the following advantages.
(A ′) The pressure in the fuel supply chamber 60 can be increased by transporting the fuel to the fuel supply chamber 60 by the pressure feeding means, and the by-product gas generated in the anode 11 enters the fuel supply chamber 60. Can be prevented. Therefore, it is possible to obtain the same effects as the advantages (a) and (b) when the second intervening layer is provided. It is also possible to provide a pressure feeding means and a second intervening layer.

(B ′) The fuel transport member 61 can be omitted.
[Modification]
The fuel cell according to the present embodiment is not limited to the above-described modifications, and includes, for example, the following modifications.

(1) The layer structure of the fuel cell according to the present embodiment is not limited to that shown in FIGS. 1 to 5, and unit cells 30 are provided on both sides of the fuel supply chamber 60 as shown in FIG. An arranged configuration may be used. FIG. 8 is a schematic cross-sectional view similar to FIG. 5, showing an example of a fuel cell in which unit cells 30 are arranged on both surfaces of the fuel supply chamber 60. In such a configuration, since the fuel supply chamber 60 needs to be open on both the upper and lower surfaces in order to supply fuel to the upper and lower two anode electrodes 11, the upper and lower surfaces are opened as the box housing 40. A member having a space is used. In such a fuel cell in which the unit cells 30 are arranged on both surfaces of the fuel supply chamber 60, one fuel supply unit is sufficient for two unit cells, so that the fuel cell can be thinned. The output per unit volume of the fuel cell can be improved.

(2) The fuel cell of the present embodiment may include two or more unit cells 30 arranged on the same plane. In this case, the fuel supply chamber 60 may be provided for each unit cell 30 or may be provided in a number smaller than that of the unit cells 30. The same applies to the fuel transport member 61.

(3) The fuel supply unit is not limited to the one composed of the fuel supply chamber 60, the fuel storage chamber 70, and the fuel transport member 61. For example, the fuel supply chamber 60 may serve as the fuel storage chamber 70, and the fuel storage chamber 70 and the fuel transport member 61 may be omitted. In addition, the fuel supply unit may be composed of a fuel storage chamber 70 that stores liquid fuel and a fuel supply chamber 60 that circulates the fuel, and the fuel transport member 61 may be omitted. In this case, the fuel storage chamber 70 and the fuel supply chamber 60 are connected by a flow path, and the liquid fuel is supplied to the fuel supply chamber 60 in a liquid state. The fuel supply chamber 60 is not limited to the above-described shape, and can also be composed of one or a plurality of channel-shaped recesses (for example, a plurality of line-shaped channels, branched channels, serpentine-shaped channels, etc.). .

(4) The outer shape of the fuel cell of the present embodiment is not limited to the shape shown in FIGS. For example, the shape (planar shape) when viewed from the thickness direction of the fuel cell may be a rectangle or the like.

(5) Unit cell 30 and exhaust heat layer 1, exhaust heat layer 1 and first intervening layer 2, first intervening layer 2 and second intervening layer, and first intervening layer 2 (or second intervening layer 2) The intervening layer) and the fuel supply unit (box housing 40) can be joined by hot pressing (thermocompression bonding) or an adhesive, but in order to obtain higher joining strength, screws, bolts and nuts, etc. Each laminated member may be fastened using the fastening member. For example, in the case where the above-mentioned pressure feeding means is provided, it is preferable to increase the adhesion between the laminated members using a fastening member in order to prevent fuel leakage from between the laminated members. FIG. 9 is a schematic cross-sectional view similar to FIG. 1, showing an example in which each laminated member is fastened using screws 90. In the example shown in FIG. 9, the communication path 1b of the exhaust heat layer 1 is directly exposed to the outside of the fuel cell without passing through the opening of the box housing 40. Therefore, the by-product gas is communicated with the communication path 1b. It is discharged directly from the end of the. The spacer 91 is a member that fills a gap between the anode current collecting layer 21 and the cathode current collecting layer 22 and can be made of, for example, a double-sided tape.

The fuel cell of the present embodiment can be a solid polymer fuel cell or a direct alcohol fuel cell, and is particularly suitable as a direct alcohol fuel cell (in particular, a direct methanol fuel cell). Examples of the liquid fuel that can be used in the fuel cell of the present embodiment include alcohols such as methanol and ethanol; acetals such as dimethoxymethane; carboxylic acids such as formic acid; esters such as methyl formate; An aqueous solution can be mentioned. The liquid fuel is not limited to one type, and may be a mixture of two or more types. In view of low cost, high energy density per volume, high power generation efficiency, etc., an aqueous methanol solution or pure methanol is preferably used. According to the present embodiment, a stable output can be obtained even when a high-concentration fuel (such as a methanol aqueous solution or pure methanol having a concentration exceeding 50 mol%) is used.

<Second Embodiment>
FIG. 10 is a schematic cross-sectional view showing an example of the fuel cell according to the present embodiment, and shows an example of the fuel cell [B]. FIG. 11 is a schematic top view of the fuel cell. In addition, sectional views taken along lines III-III, IV-IV, and VV shown in FIG. 10 are shown in FIGS. 12 to 14, respectively. The fuel cell 200 shown in these drawings is laminated on the anode electrode 11 and electrically connected to the membrane electrode assembly 20 including the anode electrode 11, the electrolyte membrane 10 and the cathode electrode 12 in this order. A unit cell 30 comprising an anode current collecting layer 21 and a cathode current collecting layer 22 stacked on and electrically connected to the cathode electrode 12; disposed below the anode electrode 11, and the anode electrode 11 side being opened. A fuel supply chamber 60 composed of an open space; a first layer 3 disposed on the fuel supply chamber 60 so as to cover an opening of the fuel supply chamber 60 (an open surface toward the anode 11), and a unit of the first layer 3 It basically comprises an intervening layer comprising a second layer 4 laminated on the surface on the battery 30 side; and a fuel storage chamber 70 for containing fuel (not shown).

A fuel supply section of the fuel cell 200 is formed by a fuel storage chamber 70 that stores liquid fuel, a fuel supply chamber 60 that circulates the fuel, and an intervening layer that is disposed so as to cover the opening of the fuel supply chamber 60. Yes. The fuel storage chamber 70 and the fuel supply chamber 60 are connected by a flow path.

The box housing 40 has a recess (groove) that forms the fuel supply chamber 60, and the fuel supply chamber 60 (internal space) is formed by laminating the first layer 3 so as to cover the recess. . Further, the box housing 40 has a portion constituting the fuel supply chamber 60 of the fuel cell 200 and a portion constituting the bottom wall and side wall of the fuel storage chamber 70 as an integral unit.

The fuel cell 200 has a by-product gas discharge unit 6 for discharging the by-product gas generated at the anode 11 to the outside of the fuel cell. In the fuel cell 200 shown in FIGS. 10 to 14, the by-product gas discharge unit 6 includes a first through hole 7 that penetrates the side wall of the box housing 40 in the thickness direction, and a second through that penetrates the first layer 3 in the thickness direction. It consists of a through hole 8 (see FIGS. 13 and 14). The second through hole 8 is disposed immediately above the first through hole 7, and these through holes communicate with each other.

The fuel cell 200 includes a box housing 40 and a lid housing 50 stacked on the cathode current collecting layer 22 and having a plurality of openings 51. The unit cell 30 is sandwiched between the box housing 40 and the lid housing 50. ing. The lid housing 50 integrally has a portion constituting the upper wall (ceiling wall) of the fuel storage chamber 70 together with a portion laminated on the cathode current collecting layer 22, and the box housing 40, the lid housing 50, and A fuel storage chamber 70 is formed by side surfaces of the unit cell 30 and the like. A sealing layer 80 made of a cured product layer of an epoxy curable resin composition or the like is provided on the end surfaces of the unit cell 30 and the intervening layer on the fuel storage chamber 70 side so that the fuel stored in the fuel storage chamber 70 does not enter. Is formed. In the fuel cell 200, the fuel storage chamber 70 is disposed on the side of the unit cell 30 and the fuel supply chamber 60 disposed below the unit cell 30.

The fuel storage chamber 70 includes an opening 73 that communicates the internal space with the outside of the fuel cell 200. The opening 73 is a through hole provided in the lid housing 50.

The fuel cell 200 generates power by the following operation. The liquid fuel that has flowed from the fuel storage chamber 70 into the fuel supply chamber 60 through the flow channel reaches the entire fuel supply chamber 60 and wets the first layer 3 of the intervening layer. The liquid fuel exuded from the first layer 3 is gas-liquid separated by the second layer 4, and only the vaporized fuel permeates to the unit cell 30 side. The vaporized fuel that has passed through the second layer 4 is supplied to the anode 11 through the opening of the anode current collecting layer 21. Then, taking a methanol aqueous solution as an example of the liquid fuel, the gaseous methanol aqueous solution supplied to the anode 11 is
CH ₃ OH + H ₂ O → CO ₂ ↑ + 6H ⁺ + 6e ⁻
This causes an oxidation reaction represented by the formula: The vaporized fuel will be consumed according to the amount of electric current generated by the fuel cell 200. To compensate for this, the liquid fuel continues to evaporate from the second layer 4 at any time. The vapor pressure of is kept substantially constant.

On the other hand, in the cathode electrode 12, oxygen in the air that has reached through the opening 51 of the lid housing 50 and the opening of the cathode current collecting layer 22, and the oxygen from the anode electrode 11 to the cathode electrode 12 are transmitted through the electrolyte membrane 10. Proton
3 / 2O ₂ + 6H ⁺ + 6e ⁻ → 3H ₂ O
The reduction reaction represented by the formula Through the above oxidation-reduction reaction, electrons move in the route of anode electrode 11 → anode current collecting layer 21 → external electronic device (load) → cathode current collecting layer 22 → cathode electrode 12 to the external electronic device. Power is supplied.

By-product gas (CO ₂ in the above formula) generated by the power generation does not enter the fuel supply chamber 60 due to the presence of the intervening layer, the opening of the anode current collecting layer 21, the second layer 4 and It is discharged to the outside of the fuel cell through the byproduct gas discharge unit 6.

The intervening layer composed of the first layer 3 and the second layer 4 disposed between the fuel supply chamber 60 and the unit cell 30 is in a state where the fuel supply to the anode 11 is uniformly controlled to an appropriate amount. Makes it possible to do with Thereby, fuel crossover can be effectively suppressed, temperature unevenness hardly occurs in the power generation unit, and a stable power generation state can be maintained.

Next, each member constituting the fuel cell 200 will be described in detail.
(Intervening layer)
(1) First layer The fuel supply chamber 60 and the unit cell 30 so as to cover the opening of the fuel supply chamber 60 (the open surface toward the anode 11) (that is, so as to cover the recess forming the fuel supply chamber 60). As shown in the example shown in FIG. 10, the intervening layer disposed between the first layer 3 and the first layer 3 stacked on the fuel supply chamber 60 so as to cover the opening of the fuel supply chamber 60. The two-layer structure of the second layer 4 laminated on the surface of the unit battery 30 can be. The first layer 3 is a layer having a bubble point of 30 kPa or more when the measurement medium is methanol, and corresponds to the “second intervening layer” described in the first embodiment. The definition of bubble point is as described above.

By arranging such a first layer 3 so as to cover the opening of the fuel supply chamber 60, liquid fuel is held in the pores of the first layer 3 by capillary force, so Intrusion of raw gas (such as CO ₂ gas) into the fuel supply chamber 60 can be effectively prevented. As a result, it is possible to prevent the supply amount of the vaporized fuel to the anode 11 from being lowered or to prevent the stable supply of the vaporized fuel from being hindered, so that the output stability of the fuel cell can be maintained well. In addition, since the by-product gas permeates and the internal pressure of the fuel supply chamber 60 increases, peeling at the interface between the constituent members and destruction of the constituent members can be suppressed, so that the reliability of the fuel cell can be improved.

The installation of the first layer 3 is also advantageous in the following points.
(A) Since the liquid fuel can be transported from the fuel storage chamber 70 into the fuel supply chamber 60 by using the capillary force of the first layer 3, the liquid fuel can be passively supplied. Thereby, auxiliary machines, such as a pump for sending liquid fuel, can be omitted. In addition, since fuel supply by capillary force is possible, the dependency on the direction of fuel supply can be eliminated (that is, power generation can be performed regardless of the direction when the fuel cell is used).

(B) When a material having low thermal conductivity such as a polymer material is used for the first layer 3, the liquid fuel held in the first layer 3 is not easily affected by a rapid temperature rise of the power generation unit. The temperature rise becomes slow. As a result, since the liquid fuel held in the first layer 3 can be stably maintained at a relatively low temperature, the supply amount of vaporized fuel supplied to the anode electrode 11 can be stabilized. This contributes to improving the reliability of the fuel cell.

(C) Since the liquid fuel is uniformly spread and held in the first layer surface, the vaporized fuel can be supplied uniformly to the anode electrode surface, and a local excessive supply of fuel to the power generation unit, Since there is no fuel shortage, deterioration of materials such as catalysts can be suppressed. This contributes to improved output and improved fuel cell reliability.

(D) Generated in the anode 11 by increasing the pressure in the fuel supply chamber 60 by a method such as pumping the liquid fuel stored in the fuel storage chamber 70 to the fuel supply chamber 60 using a pumping means such as a pump. Although it is possible to prevent the by-product gas from entering the fuel supply chamber 60 to some extent, the effect of preventing the intrusion by the first layer 3 exceeds this, so the internal pressure in the fuel supply chamber 60 is increased. There is no need. Thereby, the risk of liquid leakage due to an increase in internal pressure can be avoided, and the reliability of the fuel cell can be improved.

(E) Since the by-product gas does not enter even if the internal pressure in the anode 11 is increased, the diameter of the through-hole constituting the by-product gas discharge unit 6 can be further reduced. As a result, the discharge of unused vaporized fuel can be reduced, so that the fuel utilization efficiency can be improved (this effect will be described in detail later).

From the viewpoint of effectively preventing the byproduct gas from entering the fuel supply chamber 60, the bubble point of the first layer 3 is preferably 50 kPa or more, and more preferably 100 kPa or more. The bubble point of the first layer 3 can be controlled by adjusting the pore diameter and contact angle of the material used as the first layer 3. In order to achieve a bubble point of 30 kPa or more, the maximum pore diameter of the pores of the first layer 3 is preferably 1 μm or less, and more preferably 0.7 μm or less.

Examples of the first layer 3 include a porous layer made of a polymer material, a metal material, an inorganic material, or the like, and a polymer film. Specific examples of the first layer 3 include the above-described “second intervening layer”. The same as the specific example.

When a polymer material is used as the material constituting the first layer 3, it is subjected to a hydrophilization treatment by a method such as introduction of a hydrophilic functional group, and water on the pore surface (thus, fuel such as methanol or methanol aqueous solution). The bubble point of the 1st layer 3 can also be raised by improving the wettability with respect to. Further, by applying a hydrophilization treatment to the first layer 3, the liquid fuel can be circulated in the fuel supply chamber 60 with a lower pressure loss.

The thickness of the first layer 3 is not particularly limited, but is preferably 20 to 500 μm, more preferably 50 to 200 μm, from the viewpoint of reducing the thickness of the fuel cell.

The first layer 3 is provided with a second through hole 8 that forms a part of the by-product gas discharge part 6. The second through hole 8 is formed at a position where it communicates with the first through hole 7 when the first layer 3 is laminated on the box housing 40 (that is, directly above the first through hole 7).

(2) Second Layer The second layer 4 laminated on the surface of the first layer 3 on the unit cell 30 side is a porous layer having a hydrophobic property of vaporized fuel permeability and liquid fuel impermeability, and the anode 11 This is a layer (gas-liquid separation layer) that enables vaporization and supply of fuel to the tank. The second layer 4 corresponds to the “first intervening layer” described in the first embodiment.

The second layer 4 has a function of controlling (limiting) the amount or concentration of vaporized fuel supplied to the anode electrode 11 to an appropriate amount and making it uniform. By providing the second layer 4, fuel crossover can be effectively suppressed, temperature unevenness hardly occurs in the power generation unit, and a stable power generation state can be maintained.

The second layer 4 is not particularly limited as long as it has gas-liquid separation ability with respect to the fuel to be used, and a specific example thereof is the same as the specific example of the “first intervening layer” described above.

Since the second layer 4 has vaporized fuel permeability, it has a smaller bubble point than the first layer 3. The bubble point according to the measurement method of the second layer 4 is preferably 10 kPa or less, and the larger the contact angle of methanol with respect to the second layer 4, the better, preferably 45 degrees or more, more preferably about 90 degrees or more. . Further, from the viewpoint of imparting vaporized fuel permeability and liquid fuel impermeability, the maximum pore diameter of the pores of the second layer 4 is preferably 0.1 to 10 μm, and preferably 0.5 to 5 μm. It is more preferable. The maximum pore diameter of the pores of the second layer 4 can be determined by measuring the bubble point using methanol or the like as in the first layer 3.

The thickness of the second layer 4 is not particularly limited, but is preferably 20 μm or more and more preferably 50 μm or more in order to sufficiently express the above function. Further, from the viewpoint of reducing the thickness of the fuel cell, the thickness of the second layer 4 is preferably 500 μm or less, and more preferably 300 μm or less.

[Electrolyte membrane, anode electrode, cathode electrode, anode current collecting layer and cathode current collecting layer]
Regarding the electrolyte membrane 10, the anode 11, the cathode 12, the anode current collecting layer 21, and the cathode current collecting layer 22 included in the fuel cell of the present embodiment, the contents described in the first embodiment are cited.

[Fuel supply chamber]
The fuel supply chamber 60, together with a fuel storage chamber 70 to be described later, is a part that constitutes a fuel supply section that plays a role of fuel storage and fuel supply, and is preferably disposed directly below the anode electrode 11. In the fuel cell 200 shown in FIG. 10, the fuel supply chamber 60 has a length equal to or longer than the length from the end of the anode 11 on the fuel storage chamber 70 side to the opposite end thereof. It is composed of a space having a width equal to or greater than the width of the anode 11. The height (depth) of the fuel supply chamber 60 is not particularly limited.

In the fuel cell 200 of the present embodiment, the fuel supply chamber 60 includes a box housing 40 having a concave portion that constitutes an internal space of the fuel supply chamber 60, disposed in contact with the intervening layer below the unit cell 30, and an intervening layer And is formed by. The box housing 40 shown in FIG. 10 integrally includes the parts constituting the fuel supply chamber 60 and the parts constituting the bottom wall and the side wall of the fuel storage chamber 70, but is not limited thereto. Instead, the member constituting the fuel supply chamber 60 and the member constituting the fuel storage chamber 70 may be different members.

The box housing 40 can be manufactured by using a plastic material or a metal material and molding it into an appropriate shape so as to have at least a recess that constitutes the internal space of the fuel supply chamber 60. The specific example of the material which comprises the box housing 40 is the same as that of the said 1st Embodiment.

[By-product gas discharge section]
The fuel cell 200 of the present embodiment includes a by-product gas discharge unit 6 for discharging the by-product gas generated at the anode 11 to the outside of the fuel cell. In the fuel cell 200 shown in FIGS. 10 to 14, the by-product gas discharge unit 6 includes a first through hole 7 that penetrates the side wall of the box housing 40 in the thickness direction, and a second through that penetrates the first layer 3 in the thickness direction. It consists of a through hole 8 (see FIGS. 13 and 14). The second through hole 8 is disposed immediately above the first through hole 7, and these through holes communicate with each other. By providing the by-product gas discharge part 6, an excessive increase in internal pressure in the anode 11 can be prevented.

As described above, in the fuel cell 200 of the present embodiment, by providing the intervening layer, entry of by-product gas into the fuel supply chamber 60 is effectively prevented, so that the internal pressure in the anode 11 is temporarily increased. Even if this is done, there is no risk that the by-product gas will enter the fuel supply chamber 60. Therefore, there is an advantage that the diameter of the through hole constituting the by-product gas discharge unit 6 can be made smaller to allow the internal pressure in the anode 11 to be increased to some extent. The by-product gas discharge unit 6 can provide a route through which unused vaporized fuel (vaporized fuel before reaching the anode 11) is discharged to the outside of the fuel cell. The reduction in the diameter of the hole is extremely advantageous for reducing the amount of unused vaporized fuel discharged, thereby improving the fuel utilization efficiency. Since the conventional fuel cell does not have means for preventing the by-product gas from entering the fuel supply chamber 60, when providing a path for discharging the by-product gas, the internal pressure in the anode 11 is prevented from increasing. Therefore, the diameter has to be increased, and the fuel utilization efficiency has been reduced.

The means for discharging the by-product gas to the outside of the fuel cell includes the first through hole 7 and the second through hole 8 as shown in FIGS. 13 and 14 which the fuel cell 200 of the present embodiment has. The route is not limited to the by-product gas discharge unit 6 and may be any route extending from the vicinity of the anode 11 to the outside of the fuel cell. For example, an intervening layer is not disposed on the first through hole 7 of the box housing 40 (the size of the intervening layer is reduced), and the first through hole 7 is extended to the anode current collecting layer 21 accordingly. There may be. In this case, the by-product gas discharge part is composed of only the first through hole 7 and does not have the second through hole 8. Further, a through hole penetrating the electrolyte membrane 10 in the thickness direction may be provided, and the by-product gas may be discharged to the cathode electrode 12 side. By-product gas discharged from the through hole is oxidized at the cathode electrode 12 so that the cathode electrode 12 is positioned immediately above the through hole so that the output characteristics of the fuel cell are not deteriorated and air is not excessively consumed. A structure in which a region that is not formed may be provided. In this case, the by-product gas discharge portion is composed of a continuous space in a region where the through hole of the electrolyte membrane 10 and the cathode electrode 12 are not formed, and the by-product gas is discharged to the cathode electrode 12 side.

[Fuel storage room]
The fuel storage chamber 70 is a chamber for storing liquid fuel, which is preferably disposed on the side of the unit cell 30 and the fuel supply chamber 60. In the fuel cell 200 of the present embodiment, the fuel storage chamber 70 is formed by a lid housing 50, a box housing 40, a unit cell 30 and an intervening layer that are stacked on the cathode current collecting layer 22 and have a plurality of openings 51. The end surfaces of the unit cell 30 and the intervening layer on the side of the fuel storage chamber 70 are sealed with a sealing layer 80 made of a cured product of an epoxy curable resin composition or the like so that the fuel stored in the fuel storage chamber 70 does not enter. Has been.

The fuel storage chamber 70 does not necessarily need to be configured using the lid housing 50 and the box housing 40. For example, the fuel storage chamber 70 has a portion that forms an upper wall (ceiling wall), a side wall, and a bottom wall. It can also be comprised from one member included as one.

In the fuel cell 200, the lid housing 50 functions as a protective plate that forms the upper wall (ceiling wall) of the fuel storage chamber 70 and prevents the unit cell 30 from being directly exposed. A plurality of openings 51 (however, the number of openings may be one or more) for allowing air to flow are formed in a portion immediately above the cathode electrode 12 of the lid housing 50.

The lid housing 50 can be manufactured by using a plastic material or a metal material and molding it into an appropriate shape. The specific example of the material which comprises the lid housing 50 is the same as that of the said 1st Embodiment.

The fuel storage chamber 70 is preferably provided with an opening 73 that communicates the internal space with the outside of the fuel cell. Thereby, even when the liquid fuel is transported to the fuel supply chamber 60, since the inside of the fuel storage chamber 70 is maintained at the atmospheric pressure, the liquid fuel can be transported smoothly. In the fuel cell 200 shown in FIG. 10, the opening 73 is a through-hole penetrating the lid housing 50 in the thickness direction, but is not limited thereto.

In order to prevent liquid fuel from leaking from the opening 73, the opening diameter of the opening 73 is preferably sufficiently small (for example, a diameter of about 100 to 500 μm, preferably 100 to 300 μm), or to the outside of the fuel cell. A gas-liquid separation membrane (for example, a porous membrane made of polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, or the like) for preventing leakage of liquid fuel may be provided in the opening 73.

[Modification]
The fuel cell according to the present embodiment is not limited to the above-described modifications, and includes, for example, the following modifications. The modifications described in this embodiment can be applied to other embodiments described later.

(1) In the above embodiment, the intermediate layer has a two-layer structure of the first layer 3 disposed so as to cover the opening of the fuel supply chamber 60 and the second layer 4 stacked on the first layer 3. However, a single layer structure having a region having the same functional characteristics as the first layer 3 and a region having the same functional characteristics as the second layer 4 can be used as the intervening layer. The “single-layer structure” referred to here is composed of one member and means that it is not a combination of two members. Such an intervening layer having a single layer structure is advantageous in that poor adhesion (formation of a gap) between the first layer 3 and the second layer 4 that may occur in a two-layer structure cannot occur. If a gap is formed in a part of the interface, by-product gas stays in the gap, and the amount of vaporized fuel permeated due to excessive supply of fuel or fuel shortage in the surface of the second layer 4 may vary. There is a possibility that the gap is widened by the pressure of the gas and the fuel supply chamber 60 is closed and fuel supply is hindered.

More specifically, the intervening layer having a single-layer structure has the same functional characteristics as those of the first layer 3, which is a region on the fuel supply chamber 60 side in the thickness direction (bubbles when the measurement medium is methanol). A first region (having a point of 30 kPa or more) and a second region having the same functional characteristics as the second layer 4 (permeating vaporized fuel), which is a region on the unit cell 30 side in the thickness direction What is provided can be used. The bubble point of the 1st area | region which the intervening layer of 1 layer structure has is synonymous with the bubble point of the intervening layer of 1 layer structure. Like the relationship between the first layer 3 and the second layer 4, the bubble point of the second region is smaller than that of the first region, and the bubble point of the entire intervening layer matches that of the region where the bubble point is larger. It is.

The intervening layer having a single-layer structure is produced by, for example, a method of hydrophilizing only one region in the thickness direction of the porous layer that can be used as the second layer 4 and increasing the bubble point of the region. Can do.

Such an intervening layer having a one-layer structure is advantageous in that a poor adhesion (formation of a gap) between the first layer 3 and the second layer 4 that may occur in a two-layer structure cannot occur. If a gap is formed in a part of the interface, there is a possibility that the amount of vaporized fuel permeated in the second layer surface varies, and the fuel cannot be supplied uniformly to the fuel electrode, resulting in a decrease in output. Such a problem cannot occur if the intervening layer has a single layer structure. On the other hand, when an intervening layer having a two-layer structure is used, the first layer 3 is formed by tightening the fuel cell from above and below using a fastening member such as a bolt, nut, or screw in order to cope with the above problem. It is preferable to ensure adhesion between the first layer 4 and the second layer 4.

(2) The space shape of the fuel supply chamber 60 is not limited to that shown in FIG. The fuel supply chamber 60 may be formed of a plurality of branched flow paths as shown in FIG. 15, for example. Alternatively, it can be formed from a plurality of line-shaped channels, serpentine-shaped channels, and the like. FIG. 15 is a schematic cross-sectional view similar to FIG. 13 showing another example of the fuel supply unit (fuel supply chamber).

(3) FIG. 16 is a schematic sectional view similar to FIG. 13 showing another example of the fuel supply unit. As shown in FIG. 16, the fuel supply unit may include a fuel transport member 61 in addition to the intervening layer, the fuel supply chamber 60 and the fuel storage chamber 70. The fuel transport member 61 is a member that is disposed at least partially in the fuel supply chamber 60 and transports liquid fuel from the fuel storage chamber 70 to the fuel supply chamber 60 by utilizing capillary action. It plays the role of assisting liquid fuel transportation using the capillary force of No. 3. Regarding the fuel transport member 61, the contents described in the first embodiment are cited.

(4) The fuel supply unit is not limited to the one including the fuel supply chamber 60 and the fuel storage chamber 70. For example, the fuel supply chamber 60 may serve as the fuel storage chamber 70 that stores liquid fuel, and the fuel storage chamber 70 (and the fuel transport member 61) may be omitted.

(5) The layer configuration of the fuel cell is not limited to that shown in FIGS. 10 to 14, and the unit cell 30 is arranged on both sides of the fuel supply chamber 60 as shown in FIG. 17, for example. It may be. FIG. 17 is a schematic cross-sectional view similar to FIG. 14, showing an example of a fuel cell in which unit cells 30 are arranged on both surfaces of the fuel supply chamber 60. In such a configuration, since the fuel supply chamber 60 needs to be open on both the upper and lower surfaces in order to supply fuel to the upper and lower two anode electrodes 11, the upper and lower surfaces are opened as the box housing 40. A member having a space is used. In such a fuel cell in which the unit cells 30 are arranged on both surfaces of the fuel supply chamber 60, one fuel supply unit is sufficient for two unit cells, so that the fuel cell can be thinned. The output per unit volume of the fuel cell can be improved. In the embodiment shown in FIG. 17, as shown in the figure, the first through hole 7 is connected to the first through hole 7 and has a discharge path extending in the lateral direction on the side wall of the box housing 40. The raw gas can be discharged from the side surface of the box housing 40 through this discharge path.

(6) The fuel cell of this embodiment may include two or more unit cells 30 arranged on the same plane. In this case, the fuel supply chamber 60 may be provided for each unit cell 30 or may be provided in a number smaller than that of the unit cells 30.

(7) The outer shape of the fuel cell of the present embodiment is not limited to the shape shown in FIGS. For example, the shape (planar shape) when viewed from the thickness direction of the fuel cell may be a rectangle or the like.

(8) The fuel cell can include a pumping means such as a pump for pumping the liquid fuel accommodated in the fuel storage chamber 70 to the fuel supply chamber 60. Since the fuel supply chamber 60 can be filled in a short time, the startability of the fuel cell can be improved.

<Third Embodiment>
FIG. 18 is a schematic cross-sectional view showing an example of a fuel cell according to this embodiment. The fuel cell 300 of this embodiment is the same as that of the second embodiment except that the intervening layer disposed between the fuel supply chamber 60 and the unit cell 30 further includes the third layer 5. FIG. 19 is a schematic top view showing the third layer 5 used in the fuel cell 300. Hereinafter, the third layer, which is a feature of the present embodiment, will be described in detail. Note that the various modifications described in the second embodiment can be similarly applied to this embodiment.

The third layer 5 is a layer which is disposed between the first layer 3 and the second layer 4 and has a through hole penetrating in the thickness direction through which liquid fuel can permeate. At least the first layer 3 and the second layer 4 has a function of adjusting (limiting) the amount of liquid fuel permeation to the second layer 4 side. As the third layer 5, for example, a non-porous sheet (film) having through holes penetrating in the thickness direction as shown in FIGS. 18 and 19 can be used, and a thermoplastic resin is preferable as the material thereof. It can be illustrated. By using this, the laminated body composed of the first layer / the third layer / the second layer is subjected to thermocompression bonding so that the respective layers can be surface-bonded with good adhesion. A fuel cell having an intervening layer as the third layer 5 having a through-hole penetrating in the thickness direction and capable of surface bonding is advantageous in the following points.

(A) Since the first layer 3 and the second layer 4 can be bonded with good adhesion via the third layer 5, a by-product gas stays between the first layer 3 and the second layer 4. In other words, the variation in the vaporized fuel permeation amount in the surface of the second layer 4 can be suppressed, whereby the fuel can be supplied uniformly to the anode 11 and the output can be improved. Become. Moreover, when the 3rd layer 5 consists of resin, there exists an effect which makes it difficult to transmit heat to liquid fuel with respect to the rapid temperature rise of an electric power generation part. As a result, the temperature rise of the liquid fuel becomes slow and the liquid fuel can be stably maintained at a relatively low temperature, so that the supply amount of the vaporized fuel supplied to the anode 11 can be stabilized. This contributes to improving the reliability of the fuel cell.

(B) The amount of liquid fuel permeated to the second layer 4 side, and thus the amount of vaporized fuel supplied to the anode 11, is adjusted to an appropriate amount according to the number of through holes formed in the third layer 5 and the opening diameter (restriction). )can do. As a result, it is possible to prevent or suppress the crossover of the fuel and stabilize the fuel supply. The number of through holes is not particularly limited, but it is preferable that there are a plurality of through holes. From the viewpoint of uniformizing the amount of vaporized fuel permeated in the surface of the second layer 4, these are provided in the fuel supply chamber 60 (box housing in the third layer 5). It is preferable to uniformly distribute the region directly above the concave portion of the body 40. The opening diameter (diameter) of the through hole can be set to about 0.1 to 5 mm, for example.

(C) The third layer 5 enables good surface joining between the first layer 3 and the second layer 4, so that it is not necessary to tighten the fuel cell using a fastening member such as a bolt, nut or screw. Thus, the fuel cell can be made thinner.

(D) Since the intervening layer can be easily produced by thermocompression bonding, the fuel cell production process can be simplified and the production efficiency can be improved.

In addition to the thermoplastic resin sheet described above, the third layer 5 may be formed of, for example, the following.

1) A porous layer formed from an adhesive resin or resin composition, for example, a porous layer formed from an adhesive such as a hot-melt adhesive or a curable adhesive. When the adhesive is used, the third layer 5 is an adhesive layer, that is, a porous layer made of the adhesive or a cured product thereof. Even when such a third layer 5 is used, the same effects as in the above (a) to (c) can be obtained. The liquid fuel permeation amount to the second layer 4 side is adjusted (limited) by the pores of the porous layer.

2) A through-hole penetrating in the thickness direction, preferably including a non-porous metal plate. In this case, an adhesive layer is formed on both surfaces of the metal plate in order to ensure good adhesion to the first layer 3 and the second layer 4, and therefore the third layer 5 is formed of an adhesive layer / It has a three-layer structure of metal plate / adhesive layer. The adhesive layer is a porous layer made of an adhesive or a cured product thereof. The adhesive may be a hot melt adhesive or a curable adhesive. Even when such a third layer 5 is used, the same effects as in the above (a) to (c) can be obtained. The liquid fuel permeation amount to the second layer 4 side can be adjusted (controlled) by the number of through holes formed in the metal plate and the opening diameter, as in the case of the thermoplastic resin sheet. The adhesive layer is preferably formed so as not to block the through hole. The number of through-holes is not particularly limited, but it is preferable that a plurality of through-holes exist. From the viewpoint of uniformizing the amount of vaporized fuel permeated in the surface of the second layer 4, these are provided as fuel supply chambers (recesses in the box housing) ) Is preferably distributed uniformly in the region immediately above. The opening diameter (diameter) of the through hole can be set to about 0.1 to 5 mm, for example.

When the non-porous sheet (film) having a through-hole penetrating in the thickness direction is used as the third layer 5, or the non-porous sheet including the through-hole penetrating in the thickness direction is used as the third layer 5. In this case, a through hole is also formed at a position immediately above the second through hole 8 in the first layer 3, and the through hole, the first through hole 7 in the box housing 40, and the second through hole in the first layer 3. The by-product gas discharge part is constructed by the holes 8. On the other hand, when the third layer 5 is a porous layer formed of an adhesive resin or resin composition, the processing of the through holes is not particularly necessary.

The fuel cells of the second and third embodiments can be solid polymer fuel cells or direct alcohol fuel cells, and are particularly suitable as direct alcohol fuel cells (particularly direct methanol fuel cells). It is. Examples of the liquid fuel that can be used in the fuel cell of the present invention include alcohols such as methanol and ethanol; acetals such as dimethoxymethane; carboxylic acids such as formic acid; esters such as methyl formate; and aqueous solutions thereof. Can be mentioned. The liquid fuel is not limited to one type, and may be a mixture of two or more types. In view of low cost, high energy density per volume, high power generation efficiency, etc., an aqueous methanol solution or pure methanol is preferably used.

The fuel cell of the present invention described above can be suitably used as a power source for electronic devices, particularly small electronic devices such as mobile devices typified by mobile phones, electronic notebooks, and notebook computers.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

<Example 1>
A fuel cell having a configuration similar to that shown in FIG. 1 (however, having no lid housing 50) was produced by the following procedure.

(1) Joining between the heat exhaust layer 1 and the first intervening layer 2 By etching, a heat exhaust layer made of SUS having a shape shown in FIG. 20 and having a length of 26.5 mm, a width of 27.0 mm, and a thickness of 0.2 mm. 1 was produced. The opening ratio of the through holes 1a is 63% in total, and the ratio of the total of the eight cross-sectional areas of the communication path 1b to the total area of the side surface of the exhaust heat layer is 0.04. The unit of the numerical values shown in FIG. 20 is mm. The shaded portion indicates a groove (concave portion) having a depth of 0.14 mm. In addition, as the first intervening layer 2, a porous film made of polytetrafluoroethylene having a length of 26.5 mm, a width of 27.0 mm, and a thickness of 0.2 mm (“TEMISH (registered trademark)” manufactured by Nitto Denko Corporation) was used. NTF2026A-S06 ”and bubble point (measuring solvent: methanol) based on JIS K3832: 18 kPa) were prepared. The 1st intervening layer 2 was laminated | stacked on the surface on the opposite side to the groove formation surface of the exhaust heat layer 1, and these were joined by thermocompression bonding.

(2) Production of box housing 40 (flow path plate) and fuel transport member 61 A SUS flow having a shape shown in FIG. 21 having a length of 26.5 mm, a width of 27.0 mm, and a thickness of 1.2 mm by etching. A road board was produced. The unit of the numerical values shown in FIG. 21 is mm. The hatched portion is the fuel supply chamber 60 and is formed by a groove (concave portion) having a depth of 1.0 mm. Further, it has the same shape as the shaded portion (the size is slightly smaller than the fuel supply chamber 60 so that it can be fitted into the fuel supply chamber 60, and the end opposite to the comb tooth portion is from the flow path plate. A 1.0-mm thick pulp nonwoven fabric (“Pigeon sheet” manufactured by Oji Kinocross Co., Ltd.) was prepared and used as the fuel transport member 61. The fuel transport member 61 was fitted into the shaded portion of the flow path plate.

(3) Production of membrane electrode assembly 20 Catalyst-supported carbon particles (TEC66E50, manufactured by Tanaka Kikinzoku Co., Ltd.) having a Pt loading amount of 32.5% by weight and a Ru loading amount of 16.9% by weight, and 20% by weight of Nafion as an electrolyte (Registered trademark) alcohol solution (manufactured by Aldrich), n-propanol, isopropanol, and zirconia balls are put in a fluororesin container at a predetermined ratio and mixed at 500 rpm for 50 minutes using a stirrer. A catalyst paste for the anode electrode 11 was prepared. A catalyst paste for the cathode electrode 12 was prepared in the same manner as the catalyst paste for the anode electrode 11 except that catalyst-supporting carbon particles (TEC10E50E, manufactured by Tanaka Kikinzoku Co., Ltd.) having a Pt loading amount of 46.8% by weight were used. .

Next, a carbon paper (25BC, manufactured by SGL) having a water-repellent porous layer formed on one side is cut into a length of 35 mm and a width of 40 mm, and then the catalyst for the anode 11 is formed on the porous layer. Carbon paper, which is an anode conductive porous layer, is applied by using a screen printing plate having a window of 30 mm in length and 35 mm in width so that the amount of catalyst supported is about 3 mg / cm ² and dried. An anode electrode 11 having an anode catalyst layer formed in the upper center and having a thickness of about 200 μm was produced. In addition, on the porous layer of carbon paper of the same size, the above-mentioned catalyst paste for the cathode electrode 12 is screen-printed with a window of 30 mm length and 35 mm width so that the amount of catalyst supported is about 1 mg / cm ^2. A cathode electrode 12 having a thickness of about 70 μm in which a cathode catalyst layer was formed at the center of carbon paper, which is a cathode conductive porous layer, was produced by applying the coating plate using a plate and drying it.

Next, a perfluorosulfonic acid ion exchange membrane (Nafion (registered trademark) 117, manufactured by DuPont) having a thickness of about 175 μm is cut into a length of 35 mm and a width of 40 mm to form an electrolyte membrane 10, and the anode electrode 11 and the electrolyte membrane 10 are cut. And the cathode electrode 12 are stacked in this order so that the respective catalyst layers face the electrolyte membrane 10, and then subjected to thermocompression bonding at 130 ° C. for 2 minutes to connect the anode electrode 11 and the cathode electrode 12 to the electrolyte membrane. 10 was joined. The superposition was performed so that the positions of the anode electrode 11 and the cathode electrode 12 in the plane of the electrolyte membrane 10 coincided, and the centers of the anode electrode 11, the electrolyte membrane 10 and the cathode electrode 12 coincided. Subsequently, the membrane electrode assembly 20 having a length of 22 mm and a width of 26 mm was produced by cutting the outer peripheral portion of the obtained laminate.

(4) Production of unit cell 30 A stainless steel plate (NSS445M2, manufactured by Nisshin Steel Co., Ltd.) having a length of 26.5 mm, a width of 27 mm, and a thickness of 100 μm is prepared, and a plurality of apertures having an aperture diameter of φ0.6 mm are provided in this central region. (Open hole pattern: staggered 60 ° pitch 0.8 mm) is processed from both sides by wet etching using a photoresist mask to produce two stainless steel plates having a plurality of through holes penetrating in the thickness direction, These were designated as anode current collecting layer 21 and cathode current collecting layer 22.

Next, the anode current collecting layer 21 is laminated on the anode electrode 11 via a conductive adhesive layer made of carbon particles and an epoxy resin, and the cathode current collecting layer 22 is formed on the cathode electrode 12 with carbon particles. Are stacked via a conductive adhesive layer made of epoxy resin and bonded together by thermocompression bonding to produce a unit battery 30 having a length of 22 mm and a width of 26 mm (referring to the size of the membrane electrode assembly 20). did. The anode current collecting layer 21 and the cathode current collecting layer 22 were laminated so that the regions where the holes were formed were arranged immediately above the anode electrode 11 and the cathode electrode 12, respectively.

(5) Fabrication of fuel cell A box housing (flow channel plate) 40 / first intervening layer 2 / exhaust heat layer 1 / unit cell 30 in which the fuel transport member 61 is fitted are stacked in this order, and the box is formed by thermocompression bonding. Between the housing | casing 40 and the 1st intervening layer 2, and between the exhaust heat layer 1 and the unit cell 30 were joined. Also, a SUS casing was prepared as the fuel storage chamber 70, and a portion protruding from the box casing (flow path plate) 40 of the fuel transport member 61 was inserted into the fuel storage chamber 70 to produce a fuel cell.

<Example 2>
The exhaust heat layer 1 is the same as that of Example 1 except that the size of the 15 through holes 1a is reduced and the exhaust heat layer in which the opening ratio of the 15 through holes is 46% in total is 46%. A fuel cell was fabricated.

<Comparative Example 1>
A fuel cell was produced in the same manner as in Example 1 except that an exhaust heat layer having no communication path 1b was used.

(Fuel cell performance evaluation)
(1) Output characteristics (IV characteristics) of the fuel cells of Examples 1 and 2
Fuel is supplied by passive supply using a methanol aqueous solution with a methanol concentration of 17M as a fuel, the fuel cell is operated, and IV measurement is performed using a charge / discharge device ("SPEC20526" manufactured by Kikusui Electronics Co., Ltd.) The output characteristics of the fuel cell were evaluated. 22 and 23 are graphs showing the output characteristics of the fuel cells produced in Example 1 and Example 2, respectively. As shown in FIG. 22, the fuel cell of Example 1 showed good output characteristics, and a maximum output density of about 33 mW / cm ² was obtained. On the other hand, as shown in FIG. 23, in the fuel cell of Example 2, the degree of voltage drop when the current density was gradually increased was slightly larger than that of Example 1, and the maximum output density was also slightly decreased. .

Further, for the fuel cell of Example 1, the temperatures of the power generation unit (unit cell 30) and the fuel supply unit (fuel transport member 61) after 5 minutes from the start of operation were confirmed to be 45 ° C and 43 ° C, respectively. After that, these temperatures remained almost constant. It is presumed that this is a result of good discharge of CO ₂ and the accompanying heat and fuel supply to the anode 11.

On the other hand, in the fuel cell of Example 2, the temperature of the power generation unit and the fuel supply unit after 5 minutes from the start of operation was sufficiently low, but the temperature of the power generation unit and the fuel supply unit became 50 ° C. due to the subsequent power generation, After that, it tended to rise gradually. It is considered that the heat insulating effect by the exhaust heat layer 1 was reduced as compared with Example 1 because the opening ratio of the through-hole 1a was less than 50%.

(2) Output stability of the fuel cell of Example 1 and Comparative Example 1 The fuel cell was supplied by passive supply using a methanol aqueous solution having a methanol concentration of 17 M as a fuel, the fuel cell was operated, and constant current measurement (current density 50 mA / cm ² ) was performed, and the output stability of the fuel cells of Example 1 and Comparative Example 1 was evaluated. The results are shown in FIG. As shown in FIG. 24, when the exhaust heat layer 1 does not have the communication path 1b, CO ₂ gas as a by-product gas cannot be exhausted from the exhaust heat layer 1 and enters the fuel supply chamber 60. Therefore, it was confirmed that the fuel supply was hindered and the output stability was significantly reduced. On the other hand, the fuel cell of Example 1 showed good output stability.

<Example 3>
A fuel cell having a configuration similar to that shown in FIG.

(1) Production of membrane electrode assembly 20 Catalyst-supported carbon particles (TEC66E50, manufactured by Tanaka Kikinzoku Co., Ltd.) having a Pt loading amount of 32.5% by weight and a Ru loading amount of 16.9% by weight, and 20% by weight of Nafion as an electrolyte (Registered trademark) alcohol solution (manufactured by Aldrich), n-propanol, isopropanol, and zirconia balls are put in a fluororesin container at a predetermined ratio and mixed at 500 rpm for 50 minutes using a stirrer. A catalyst paste for the anode electrode 11 was prepared. A catalyst paste for the cathode electrode 12 was prepared in the same manner as the catalyst paste for the anode electrode 11 except that catalyst-supporting carbon particles (TEC10E50E, manufactured by Tanaka Kikinzoku Co., Ltd.) having a Pt loading amount of 46.8% by weight were used. .

Also, two pieces of carbon paper (GDL25BC, manufactured by SGL) cut into a length of 23 mm and a width of 28 mm were prepared, and an anode conductive porous layer and a cathode conductive porous layer were prepared, respectively.

On the anode conductive porous layer, the above-mentioned catalyst paste for anode electrode 11 is applied using a screen printing plate having a window of 22 mm in length and 27 mm in width so that the amount of supported catalyst is about 3 mg / cm ^2. Then, by drying, an anode electrode 11 having a thickness of about 100 μm in which an anode catalyst layer was formed in the center of the anode conductive porous layer was produced. Further, on the cathode conductive porous layer, a screen printing plate having a window of 22 mm in length and 27 mm in width so that the amount of catalyst supported on the cathode electrode 12 is about 1 mg / cm ² is used. By coating and drying, a cathode electrode 12 having a thickness of about 50 μm in which a cathode catalyst layer was formed in the center of the cathode conductive porous layer was produced.

Next, a perfluorosulfonic acid ion exchange membrane (Nafion (registered trademark) 117, manufactured by DuPont) having a thickness of about 175 μm is cut into a length of 23 mm and a width of 28 mm to form an electrolyte membrane 10, and the anode electrode 11 and the electrolyte membrane 10 and the cathode electrode 12 are stacked in this order so that the respective catalyst layers face the electrolyte membrane 10, and then subjected to thermocompression bonding at 130 ° C. for 2 minutes to connect the anode electrode 11 and the cathode electrode 12 to the electrolyte. Bonded to membrane 10. The superposition was performed so that the positions of the anode electrode 11 and the cathode electrode 12 in the plane of the electrolyte membrane 10 coincided, and the centers of the anode electrode 11, the electrolyte membrane 10 and the cathode electrode 12 coincided. Next, the end of the obtained laminate was cut to prepare a membrane electrode assembly 20 having a length of 22 mm and a width of 27 mm.

(2) Production of unit cell 30 A stainless steel plate (NSS445M2, manufactured by Nisshin Steel Co., Ltd.) having a thickness of 100 μm, a length of 22 mm, and a width of 27 mm is prepared, and a plurality of through-holes having an opening diameter of φ0.6 mm are formed in this central region. Two stainless steel plates having a plurality of through-holes penetrating in the thickness direction were produced by processing a hole pattern: zigzag 60 ° pitch 0.8 mm) from both sides by wet etching using a photoresist mask. Subsequently, in order to improve corrosion resistance and reduce electric resistance, the surfaces of these stainless steel plates were plated with gold to form an anode current collecting layer 21 and a cathode current collecting layer 22, respectively. The anode current collecting layer 21 and the cathode current collecting layer 22 are provided with electrical contacts for sweeping current during evaluation.

Next, the anode current collecting layer 21 is laminated on the anode electrode 11 via a conductive adhesive layer made of carbon particles and an epoxy resin, and the cathode current collecting layer 22 is formed on the cathode electrode 12 with carbon particles. A unit battery 30 having a length of 22 mm and a width of 27 mm was produced by laminating the layers via a conductive adhesive layer made of epoxy resin and bonding them by thermocompression bonding. The anode current collecting layer 21 and the cathode current collecting layer 22 were laminated so that the regions where the through holes were formed were disposed immediately above the anode electrode 11 and the cathode electrode 12, respectively.

(3) Production of Intervening Layer As a first layer 3 of the intervening layer, a porous film made of polyvinylidene fluoride having a length of 25 mm, a width of 27 mm, and a thickness of 0.1 mm as shown in FIG. 25 (Durapore membrane filter made by MILLIPORE) ) Was used. The maximum pore diameter of the pores of this porous film was 0.1 μm, and the bubble point based on JIS K3832 was 115 kPa when methanol was used as the measurement medium.

As shown in FIG. 25, the first layer 3 has through holes (inner diameter 1.0 mm) penetrating in the thickness direction as “hole group A” (five included in a region surrounded by a dotted frame). And a through hole (inner diameter 1.0 mm) penetrating in the thickness direction, denoted as “hole group B” (12 included in a region surrounded by another dotted frame). The hole group A is a hole for extracting air existing in the fuel supply chamber 60 when the liquid fuel enters the fuel supply chamber 60 disposed below the first layer 3 (the liquid is removed by extracting air). Fuel). When the hole group A is provided, the air in the fuel supply chamber 60 can be extracted even after the first layer 3 is completely wetted with fuel. The inside of the supply chamber 60 is always filled with liquid fuel. Since the unit cell 30 is not disposed on the hole group A, the by-product gas does not enter the fuel supply chamber 60 through the hole group A. On the other hand, the hole group B is the above-mentioned “second through hole 8” for discharging the by-product gas to the outside of the fuel cell, and constitutes a part of the by-product gas discharge unit.

In addition, as the second layer 4 of the intervening layer, a porous film made of polytetrafluoroethylene having a length of 25 mm, a width of 27 mm, and a thickness of 0.2 mm as shown in FIG. 26 (“TEMISH” manufactured by Nitto Denko Corporation) (Registered trademark)] NTF2122A-S06 ”). The bubble point according to JIS K 3832 of this porous film was 18 kPa when the measurement medium was methanol.

The second layer 4 is laminated on the first layer 3 (lamination so that the AA ′ planes in FIGS. 25 and 26 coincide with each other), and the layer boundary portions on all side surfaces are joined with an adhesive to form an intervening layer. Produced. The bubble point of the intervening layer coincides with the value of the layer having the largest bubble point among the constituent layers. Therefore, the bubble point of the intervening layer of this example is 115 kPa.

(4) Fabrication of fuel supply section As shown in FIG. 27, five concave portions (spaces to become the fuel supply chamber 60) having a length of 23.5 mm, a width of 1.0 mm, and a depth of 0.4 mm are formed on one surface. Further, a box housing 40 having a length of 30 mm, a width of 27 mm, and a thickness of 0.6 mm, in which a total of 12 first through holes 7 having an inner diameter of 1.0 mm were formed at the illustrated positions, was prepared. The box housing 40 has the same shape as that shown in FIG. 10, and includes a recess that constitutes the fuel storage chamber 70 on the side of the recess that becomes the fuel supply chamber 60. After interposing the intervening layer on the concave portion of the box housing 40 via a polyolefin-based adhesive so that the first layer 3 side of the intervening layer becomes the box housing 40 side (the AA ′ plane in FIGS. 25 to 27 is The intervening layer and the box housing 40 were joined by performing thermocompression bonding. The second through hole 8 (hole group B) of the first layer 3 is disposed immediately above the first through hole 7 of the box housing 40.

(5) Unit cell 30 and sealing of end surface of fuel supply unit Unit cell 30 so that the long side end surface of unit cell 30 overlaps the AA ′ surface of the fuel supply unit (intervening layer and box housing 40). Was laminated on the intervening layer. Next, the end surfaces of both the unit cell 30 and the fuel supply unit were coated with a sealing layer made of an epoxy resin by applying and curing a coating solution containing an epoxy resin using a mask. As a result, it is possible to prevent air from entering the fuel electrode from the outside of the fuel cell and fuel from leaking to the outside of the fuel cell.

(6) Fabrication of fuel cell The sealing layer 80 (fuel intrusion prevention layer) was formed by applying and curing an epoxy resin on the end surfaces of the unit cell 30 and the intervening layer on the fuel storage chamber 70 side. Finally, a fuel cell was obtained by disposing a lid housing 50 having an opening 51 for supplying air to the cathode electrode 12 and an opening 73 (pressure adjusting hole) on the unit cell 30.

<Example 4>
As the first layer 3 of the intervening layer, the same shape as the porous film used in Example 3 (the shape shown in FIG. 25, which has the hole group A and the hole group B), the thickness, and the material However, a porous film (Durapore membrane filter, filter code: DVPP manufactured by MILLIPORE) having different maximum pore diameters was used. The maximum pore diameter of the pores of this porous film was 0.65 μm, and the bubble point based on JIS K3832 was 42 kPa when the measurement medium was methanol.

The second layer 4 is the same as that of Example 3, and the second layer 4 is laminated on the first layer 3 (laminated so that the AA ′ planes in FIGS. 25 and 26 coincide), and all the side surfaces are laminated. An intervening layer was produced by joining the boundary portions of the layers with an adhesive. A fuel cell was obtained in the same manner as in Example 3 except that this intervening layer was applied to the fuel supply unit. The bubble point of the intervening layer of this example is 42 kPa.

<Example 5>
A fuel cell having a configuration similar to that shown in FIG.

As the third layer 5 of the intervening layer, a thermoplastic film (“FB-ML4” manufactured by Nitto Shinko Co., Ltd.) having a length of 25 mm, a width of 27 mm and a thickness of 0.07 mm as shown in FIG. 28 was used. The third layer 5 has through holes (inner diameter: 1.0 mm) penetrating in the thickness direction as “hole group C” (25 included in a region surrounded by a dotted frame), and the first layer 3 The same number of through-holes (inner diameter: 1.0 mm) are also provided at positions immediately above the hole groups A and B provided in (see FIG. 28). Although the film itself constituting the third layer 5 is impermeable to fuel, the fuel can pass through the hole group C from the first layer 3 side to the second layer 4 side.

The first layer 3 and the second layer 4 are the same as those in Example 3, and the first layer 3, the third layer 5, and the second layer 4 are laminated in this order (the AA ′ plane in FIGS. 25, 26, and 28). And laminated at 130 ° C. for 10 minutes to produce an intervening layer. A fuel cell was obtained in the same manner as in Example 3 except that this intervening layer was applied to the fuel supply unit. The bubble point of the intervening layer in this example is 115 kPa.

<Comparative Example 2>
Implemented except that the first layer 3 of the intervening layer is a porous film made of ultra high molecular weight polyethylene having a length of 25 mm, a width of 27 mm, and a thickness of 0.1 mm (“Sunmap LC series” manufactured by Nitto Denko Corporation). An intervening layer was produced in the same manner as in Example 3, and a fuel cell was produced in the same manner as in Example 3 except that this intervening layer was used. The bubble point based on JIS K3832 of the 1st layer used by this comparative example was 8 kPa when the measurement medium was methanol. The bubble point of the intervening layer of this comparative example is 18 kPa (corresponding to the bubble point of the second layer 4).

(Evaluation of power generation characteristics of fuel cells)
Using methanol aqueous solution as fuel, fuel was supplied by passive supply, the obtained fuel cell was operated, and IV measurement was performed using a charge / discharge device (“SPEC20526” manufactured by Kikusui Electronics Co., Ltd.) The maximum instantaneous output was evaluated, and constant current measurement (current density 75 mA / cm ² ) was performed using the same apparatus. The output stability was evaluated based on the difference between the voltage after 2 hours of measurement and the reference voltage with reference to the voltage after 5 minutes when a constant current load was applied. The results are shown in Table 1. The greater the voltage difference, the less output stability is due to the by-product gas entering the fuel supply chamber 60 and the like.

The concentration of the aqueous methanol solution supplied was 12 mol / dm ³ for the fuel cells of Examples 3 and 4 and Comparative Example 2. On the other hand, for the fuel cell of Example 5, methanol crossover was suppressed by the third layer 5 of the intervening layer, and when the same concentration of fuel as in Examples 3 and 4 and Comparative Example 2 was used, the cell temperature was relatively Therefore, an aqueous methanol solution having a concentration of 23 mol / dm ³ and a battery temperature equivalent to that of Examples 3 and 4 and Comparative Example 2 was used as the fuel.

The fuel cell of Example 3 was excellent in output stability although the instantaneous maximum output was comparable to that of Comparative Example 2. This is probably because by-product gas does not enter the fuel supply chamber 60 and the stable fuel supply is possible because the bubble point of the intervening layer is large. The fuel cell of Example 4 had the same instantaneous maximum output and output stability as those of Example 3. As in the third embodiment, it is considered that the by-product gas does not enter the fuel supply chamber 60 and stable fuel supply is possible. The fuel cell of Example 5 was excellent in both instantaneous maximum output and output stability. The reason why the instantaneous maximum output is improved is considered to be that the fuel supply becomes better and the limit current density is improved because the fuel having a higher concentration can be used. Further, the output stability of the fuel cell of Example 5 is further improved as compared with Example 3. This is because the first layer 3 and the second layer 4 are surface-bonded by the third layer 5. This is considered to be because a gap is less likely to be formed between the first layer 3 and the second layer 4 and a more stable fuel supply is performed. In the fuel cell of Comparative Example 2, the output stability was too low to perform a constant current load of 2 hr, and the measurement was finished because the cell voltage was 0.1 V or less (the voltage difference compared with after 5 min is 0.3V or more).

1 exhaust heat layer, 1a through port, 1b communication path, 1c, 1d connection path, 1st intervening layer, 3rd layer, 1st layer, 4th layer, 5th layer, 6th by-product gas discharge section, 7th 1 through hole, 8 second through hole, 10 electrolyte membrane, 11 anode electrode, 12 cathode electrode, 20 membrane electrode composite, 21 anode current collecting layer, 22 cathode current collecting layer, 30 unit cell, 40 box housing, 50 lid Housing, 51 opening, 60 fuel supply chamber, 61 fuel transport member, 63 first opening, 70 fuel storage chamber, 71 second opening, 73 opening, 80 sealing layer, 90 screws, 91 spacer (both sides) Tape, etc.), 100, 200, 300 fuel cells.

Claims (24)

A unit cell having an anode electrode, an electrolyte membrane, and a cathode electrode in this order;
A fuel supply unit disposed on the anode electrode side of the unit cell and supplying fuel to the anode electrode;
An exhaust heat layer disposed between the unit cell and the fuel supply unit;
Including
The exhaust heat layer is
A through hole penetrating in the thickness direction;
A communication path provided at a peripheral portion of the exhaust heat layer and communicating the through hole and the outside of the exhaust heat layer;
A fuel cell. 2. The fuel cell according to claim 1, wherein the exhaust heat layer has two or more through-holes and one or more communication paths that communicate any one of the through-holes with the outside of the exhaust heat layer. The fuel cell according to claim 1, wherein the opening ratios of the through holes are 50% or more in total. The fuel cell according to claim 1, wherein the through-hole has a thickness of 100 to 1000 µm. 2. The fuel cell according to claim 1, wherein a ratio of a total cross-sectional area S ₁ of the communication path to a total area S ₀ of side surfaces of the exhaust heat layer is greater than ₀ and less than 0.3. The fuel cell according to claim 1, wherein the exhaust heat layer is made of a metal plate in which the through hole and the communication path are formed by etching. The fuel cell according to claim 1, further comprising a first intervening layer that is a hydrophobic porous layer disposed between the exhaust heat layer and the fuel supply unit. 2. The fuel cell according to claim 1, wherein the fuel supply unit includes a fuel supply chamber configured to circulate or contain the liquid fuel in a space in which the anode electrode side is open. The fuel supply unit
The fuel supply chamber for circulating the liquid fuel;
A fuel storage chamber connected to the fuel supply chamber for containing the liquid fuel;
The fuel cell according to claim 8, comprising: 10. The fuel cell according to claim 9, further comprising a pumping means for pumping the liquid fuel accommodated in the fuel storage chamber to the fuel supply chamber. The fuel supply unit
A fuel storage chamber that is disposed on a side of the fuel supply chamber and contains the liquid fuel;
A member made of a material exhibiting a capillary action with respect to the liquid fuel, one end of which is disposed at a position where the liquid fuel is accommodated in the fuel storage chamber, and the other end is the fuel. A fuel transport member disposed in the supply chamber and extending so as to face the anode electrode;
The fuel cell according to claim 8, further comprising: 10. The fuel cell according to claim 9, wherein the communication path is provided at a peripheral portion of the exhaust heat layer farthest from the fuel storage chamber. A first intervening layer that is a hydrophobic porous layer disposed between the exhaust heat layer and the fuel supply chamber;
A second intervening layer that is disposed between the first intervening layer and the fuel supply chamber so as to cover the opening of the fuel supply chamber, and has a bubble point of 30 kPa or more when the measurement medium is methanol;
The fuel cell according to claim 8, further comprising: 2. The fuel cell according to claim 1, wherein the unit cell further includes an anode current collecting layer laminated on the anode electrode and a cathode current collecting layer laminated on the cathode electrode. A fuel cell comprising: a unit cell having an anode electrode, an electrolyte membrane, and a cathode electrode in this order; and a fuel supply unit that is disposed on the anode electrode side of the unit cell and supplies fuel to the anode electrode. ,
The fuel supply unit includes a space in which the anode electrode side is opened, a fuel supply chamber for circulating or containing the liquid fuel, and the fuel supply chamber so as to cover an opening of the fuel supply chamber. An intervening layer disposed between the unit cells,
The intervening layer is provided on the fuel supply chamber side in the thickness direction, and is provided on the first cell region where the bubble point is 30 kPa or more when the measurement medium is methanol, and on the unit cell side in the thickness direction. And a second region capable of permeating the vaporized fuel. The intervening layer is disposed on the fuel supply chamber so as to cover the opening of the fuel supply chamber, and a first layer having a bubble point of 30 kPa or more when methanol is used as a measurement medium; and a unit in the first layer The fuel cell according to claim 15, wherein the fuel cell has a two-layer structure including a second layer that is laminated on the cell side surface and is capable of transmitting the vaporized fuel. The fuel cell according to claim 16, further comprising a third layer having a through hole penetrating in the thickness direction between the first layer and the second layer. The fuel cell according to claim 17, wherein the third layer is a thermoplastic resin sheet having a plurality of through holes penetrating in the thickness direction. The fuel cell according to claim 17, wherein the third layer is a porous layer formed of an adhesive resin or resin composition. The fuel cell according to claim 17, wherein the third layer includes a metal plate having a plurality of through holes penetrating in the thickness direction. The fuel cell according to claim 15, wherein the unit cell further includes an anode current collecting layer laminated on the anode electrode and a cathode current collecting layer laminated on the cathode electrode. The fuel cell according to claim 15, wherein the fuel is pure methanol or an aqueous methanol solution. An electronic device comprising the fuel cell according to claim 1. An electronic device comprising the fuel cell according to claim 15.

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