JP2010123350A - Fuel battery - Google Patents

Abstract

An object of the present invention is to effectively prevent the end face edge of a porous body from sticking into a diffusion layer base material or a current collecting layer while maintaining a compressive force during stacking at a desired value, thereby improving cross leak durability. An excellent fuel cell is provided.
A porous body (expanded metal 5) in which an electrode body 10 is formed from a membrane electrode assembly 3 and gas diffusion layers 4 and 4 on an anode side and a cathode side sandwiching the membrane electrode assembly 3 to form a gas flow path layer. And the separator 7 sandwich the electrode body 10 to form a fuel cell 100. In the fuel cell formed by stacking the fuel cell 100, the gas diffusion layer 4 constitutes the membrane electrode assembly 3. A diffusion layer base material 41 surrounding the current collection layer 42 and a plurality of edges 51a on the end face of the expanded metal 5 of the diffusion layer base material 41. A protrusion 41 a that protrudes toward the expanded metal 5 is formed at a location where the contact is made.
[Selection] Figure 1

Description

  The present invention relates to a fuel cell, and more particularly to a fuel cell including a porous body such as an expanded metal or a metal foam sintered body as a gas flow path layer.

  A fuel cell of a polymer electrolyte fuel cell includes a membrane electrode assembly (MEA) from an ion-permeable electrolyte membrane and an anode-side and cathode-side catalyst layer (electrode layer) sandwiching the electrolyte membrane. Gas diffusion layers (GDL: Gas Diffusion Layer) for collecting electricity generated by electrochemical reaction while providing fuel gas or oxidant gas to the membrane electrode assembly Is sandwiched to form an electrode body (MEGA), and this electrode body is configured by sandwiching a separator in which linear or meandering gas flow channel grooves are integrally formed. As this separator, there is also a so-called flat type separator in which the gas flow path layer is formed from, for example, an expanded metal or a metal foam sintered body disclosed in Patent Document 1 and separated from the separator. The fuel cell stack is formed by stacking a predetermined number of the fuel cells according to required power.

  In the fuel cell described above, hydrogen gas or the like is provided as a fuel gas to the anode electrode, oxygen or air is provided as the oxidant gas to the cathode electrode, and each electrode has its own gas channel layer (or the gas channel of the separator). The gas flows in the in-plane direction at the groove), and then the gas diffused in the gas diffusion layer is guided to the catalyst layer to cause an electrochemical reaction.

  In assembling the fuel cell, a predetermined number of fuel cells are stacked and stacking is performed by applying a given compressive force from both side ends via tension plates. This compressive force enhances the adhesion at the interface between the constituent members of the fuel cell (such as between the separator and the gas diffusion layer, or between the gas diffusion layer and the membrane electrode assembly), thereby enabling contact resistance at the interface. The size is adjusted so as to reduce it. Furthermore, the relative compressive force at the component interface changes depending on the usage environment of the fuel cell (for example, the component member expands or the gas pressure increases in a high temperature environment during high load power generation). Since the relative compressive force changes with the thickness reduction of the accompanying component, the compressive force desired for stacking is set in consideration of these factors.

  When the compressive force is applied to each fuel cell during stacking, the compressive force is transmitted to the gas diffusion layer through the gas flow path layer made of a separator or a porous body that is a constituent member thereof.

  As the porous body forming the gas flow path layer, there are the expanded metal and the metal foam sintered body described above. For example, in a fuel cell having a gas flow path layer made of expanded metal, the above compressive force is the expanded metal. It is easy to understand that the effect is concentrated on the gas diffusion layer from the edge on the electrode body side. This will be described with reference to FIG. 3 illustrating the structure of the fuel cell on the cathode side. In the illustrated fuel cell, a membrane electrode assembly a is formed from an electrolyte membrane a1 and a cathode-side and anode-side catalyst layer a2, and this is formed into a cathode comprising a diffusion layer base material b1 and a current collecting layer b2 (MPL). An electrode body c is formed by sandwiching the gas diffusion layer b on the side and the anode side, an expanded metal e serving as a gas flow path layer contacts the gas diffusion layer b, and a flat type separator having a three-layer structure, for example, The fuel cell is constituted by contact of f. In general, a protective film d is interposed between the diffusion layer substrate b1 and an exposed region of the peripheral edge of the electrolyte membrane a1 that is not covered with the catalyst layer a2, and this is the diffusion layer substrate. It effectively protects the fluff protruding from d1 from piercing the electrolyte membrane a1. Further, in the fuel cell, a region where the catalyst layer a2 and the current collecting layer b2 are present is a power generation region (A1 region in the figure, which directly contributes to power generation), and an outer peripheral region thereof is a non-power generation region ( These can be referred to as A2 areas in the figure).

  When a predetermined number of illustrated fuel cells are stacked and stacked, a compression force P (fastening force) at the time of stacking acts on the expanded metal e and the electrode body c via the separator f. It becomes. Here, in the expanded metal e, on the side surface that comes into contact with the diffusion layer base material b1, a large number of edges protrude toward the diffusion layer base material side as shown in the figure, and the compressive force P described above applies these edges. The diffusion layer base material b1 is pressed in a concentrated manner (concentrated load P1), and in some cases, the edge pierces the diffusion layer base material b1 with the compressive force P and is embedded in the diffusion layer base material b1. turn into. Due to the piercing of these edges, in some cases, the diffusion layer base material b1 may buckle and may be damaged. Further, when the edge of the expanded metal e pierces the diffusion layer base material b1, the concentrated load continues to act on the pierced portion through the edge, so that the crack caused by the piercing progresses and a gas cross leak path can be formed. Sex also arises.

  By the way, in the non-power generation region A2 shown in the drawing, the relatively high rigidity protective film d is interposed between the electrolyte membrane a1 and the diffusion layer base material b1, so that the expanded metal e described above is applied to the diffusion layer base material b1. Even when pierced, it does not lead to the formation of a gas cross leak path. In addition, as shown in the figure, other cell structure forms that do not include the protective film d, for example, a resin material for a resin gasket (not shown) formed on the periphery of the electrode body impregnates the interposed portion of the protective film in the figure. The same applies to a cell structure in which a protective layer such as the illustrated protective film is formed.

  However, in the power generation region A1 where there is no protective film or the like, the risk that the developed crack penetrates the anode side electrode and the cathode side electrode of the membrane electrode assembly and leads to the formation of a cross leak path cannot be denied. .

  In order to eliminate the above-mentioned problems, if the compression force at the time of stacking is reduced to prevent edge sticking, the contact resistance at the interface between the components of the fuel cell increases due to insufficient compression force (fastening force). Therefore, this is not an appropriate coping approach because it directly affects the power generation performance of the fuel cell.

JP 2005-293944 A

  The present invention has been made in view of the above-described problems, and while maintaining a given compressive force at the time of stacking, the compressive force is concentrated from the edge protruding from the end face of the porous body forming the gas flow path layer. Even when this occurs, the edge pierces at least the gas diffusion layer (diffusion layer substrate or current collecting layer) constituting the power generation region of the electrode body, and further, the membrane electrode assembly may be damaged by the piercing of the edge. An object of the present invention is to provide a fuel cell capable of effectively suppressing the problem of forming a gas cross leak path.

  In order to achieve the above object, a fuel cell according to the present invention has a porous electrode in which an electrode body is formed from a membrane electrode assembly and an anode side and cathode side gas diffusion layer sandwiching the membrane electrode assembly to form a gas flow path layer. In the fuel cell in which the fuel cell is formed by sandwiching the electrode body with the electrode body and the separator, and the fuel cell is laminated, the gas diffusion layer is in contact with the catalyst layer constituting the membrane electrode assembly. A current collecting layer in contact with the diffusion layer base material surrounding the current collection layer, and a portion of the diffusion layer base material that is in contact with a plurality of edges of the end face of the porous body is provided on the porous body side. Projecting protrusions are formed.

  The fuel cell constituting the fuel cell of the present invention has a gas diffusion layer (diffusion layer base material) of the porous body forming the gas flow path layer with respect to the end surface edge protruding from the end surface on the gas diffusion layer side. A protrusion is provided at a position corresponding to the end face edge, and the end face edge is brought into contact with the protrusion, so that, for example, the concentrated load acting from the end face edge of the porous body during stacking is directly supported by the protrusion. By dispersing the concentrated load acting through the projection and the diffusion layer base material and transmitting it to the membrane electrode assembly, it is possible to effectively generate cracks due to the concentrated load at least in the power generation region of the membrane electrode assembly. It is a fuel cell that can be deterred.

  Here, the porous body forming the gas flow path layer may be either an expanded metal or a metal foam sintered body, but the edge length protruding from the end face of the porous body is relatively long, and the number of edges The fuel cell according to the present invention having the above-described characteristic configuration is particularly effective when using an expanded metal in which the concentrated load becomes relatively large because of relatively small amount of. In addition, when the porous body is made of expanded metal, it is intermittently sheared while continuously extruding the metal plate, and when the metal plate (metal mesh) after shearing is stretched, the pores such as trapezoid and rhombus The porous body which has this will be formed. When viewed in a longitudinal section, the metal mesh defining the pores has an aspect in which inclined metal beams (the end surfaces of the metal beams become the above-described edges) are arranged intermittently. Therefore, when the porous body is made of expanded metal, it is easy to specify the interval and position of the end face edges, and therefore, a gas diffusion layer (diffusion layer base material) having protrusions at positions corresponding to many end face edges is manufactured. easy.

  The protrusions described above may be provided on the porous body side end surface of either the anode side or the cathode side, or may be provided on the porous body side end surfaces of both diffusion layer base materials. Even when it is provided only on either the anode side or the cathode side, depending on the conditions such as the compressive force, the material of the diffusion layer base material and its thickness, the concentrated load acting from both the anode side and the cathode side On the other hand, when it can be determined that no cracks occur in the gas flow path layer or the membrane electrode assembly, it is not always necessary to provide them on both sides. In addition, in order to prevent cracks from occurring at least in the power generation region of the membrane electrode assembly, it is only necessary that the above-described protrusions be provided in at least the power generation region of the end surface on the porous body side of the diffusion layer base material.

  Another embodiment of the fuel cell according to the present invention comprises a membrane electrode assembly, and a current collecting layer and a diffusion layer base material disposed on either the anode side or the cathode side that sandwich the membrane electrode assembly. An electrode body is formed from a gas diffusion layer and a current collecting layer disposed on the other side, and a porous body and a separator forming a gas flow path layer sandwich the electrode body to form a fuel cell, and the fuel In the fuel cell formed by stacking battery cells, among the diffusion layer base material and the current collecting layer arranged on the other side, at least a plurality of end surfaces of the porous body in the current collecting layer arranged on the other side A protrusion that protrudes toward the porous body is formed at a position in contact with the edge.

  In the fuel cell constituting the fuel cell of the present embodiment, the gas diffusion layer on either the anode side or the cathode side does not include the diffusion layer base material, that is, one from the diffusion layer base material and the current collector. The other is a fuel cell having a gas diffusion layer consisting of only a current collecting layer. That is, in this specification, in the fuel cell of this embodiment, a case where the diffusion layer base material does not exist and only the current collecting layer is included in the gas diffusion layer.

  In the present embodiment, even when a diffusion layer base material that can be elastically deformed in only one of the two electrodes exists in the constituent members of the fuel cell, the compressive force is applied to the membrane by the elastic deformation. The other diffusion layer base material is abolished under the idea that it can be uniformly applied to one surface of the electrode assembly. For example, on the cathode side where a chemical reaction between protons and oxygen occurs, the diffusion layer base is formed on the cathode side in accordance with the design philosophy of making the compressive force acting on the membrane electrode assembly as uniform as possible in the plane. A gas diffusion layer having a material is preferably provided, and only a current collecting layer is provided on the anode side.

  Furthermore, in the present embodiment, at least the above-described protrusion is provided on the porous body side end face of the current collecting layer on the electrode side that does not include the diffusion layer base material, and the end face edge of the porous body is supported by this protrusion. . In addition, the form which provided the same protrusion also in the porous body side surface of the diffusion layer base material of the other electrode may be sufficient.

  Moreover, the current collection layer on the electrode side not provided with the diffusion layer base material can ensure its workability (handling property) by manufacturing it as a sheet (or film), for example. A current collecting layer can be provided on one surface of the membrane electrode assembly by hot pressing the produced film-like catalyst layer on the surface of the catalyst layer. This current collecting layer is composed of conductive materials such as platinum, palladium, ruthenium, rhodium, iridium, gold, silver, copper and their compounds or alloys, conductive carbon (carbon) materials, and fluororesins. It can be formed from a water repellent polymer.

  According to the fuel cell of the present invention having the porous body described above, at least the electrode body (diffusion layer base material) while maintaining the compression force during stacking at a desired value (without reducing the compression force during stacking). In addition, it effectively eliminates the problem that the edge of the porous body pierces into the power generation region of the current collecting layer and damages the membrane electrode assembly or forms a gas cross-leakage path due to the piercing of the edge. It becomes possible.

  As can be understood from the above description, according to the fuel cell of the present invention, the end face edge of the porous body pierces the diffusion layer base material or the current collecting layer while maintaining the compression force at the time of stacking at a desired value. A fuel cell that can be effectively suppressed and has excellent cross leak durability can be obtained.

Embodiments of the present invention will be described below with reference to the drawings. In addition, although the metal porous body of the example of illustration consists of an expanded metal, a metal porous body may be formed from a metal foam sintered body other than this expanded metal. In this case, for example, by baking a paste made of metal particles made of conductive metal particles such as nickel, titanium, and stainless steel, a foam material made of sodium hydrocarbon, TiH _{2 and the} like, and a solvent into a predetermined shape. A porous body made of a metal foam sintered body is obtained.

  FIG. 1 is a longitudinal sectional view of an embodiment of a fuel cell constituting the fuel cell of the present invention. The structure of the fuel cell 100 shown in FIG. 1 is that a membrane electrode assembly 3 (MEA) is formed from an electrolyte membrane 1 that is an ion exchange membrane and catalyst layers 2 and 2 on the cathode side and anode side. And the anode side gas diffusion layers 4 and 4 (GDL) are sandwiched to form an electrode body 10 (MEGA). The cathode body and anode side gas flow path layers 5 and 5 are sandwiched between the electrode body 10 and The gas flow path layers 5 and 5 are sandwiched by separators 7 and 7 having a three-layer structure, and a resin gasket 8 is integrally formed on the periphery of the electrode body 10. Further, the area of the catalyst layer 2 is smaller than that of the electrolyte membrane 1, and therefore, there is an exposed region where the catalyst layers 2, 2 do not exist at the periphery of the catalyst layers 2, 2 on both sides of the electrolyte membrane 1. In this exposed region, cathode-side and anode-side protective films 6, 6 are arranged to prevent fluff protruding from the gas diffusion layers 4, 4 from sticking into the electrolyte membrane 1. . Note that the fuel cell 100 shown in the figure shows a state before the compressive force at the time of stacking is applied, and therefore, protrusions 41a,... The expanded metal 5 is not crushed by the concentrated load acting from the end face edge 51a.

  Here, the electrolyte membrane 1 constituting the membrane electrode assembly 3 includes, for example, a fluorine ion exchange membrane having a sulfonic acid group or a carbonyl group, a substituted phenylene oxide, a sulfonated polyaryletherketone, a sulfonated polyarylethersulfone, It is formed from a non-fluorine polymer such as sulfonated phenylene sulfide. The catalyst layer 2 is a mixture of a conductive carrier (particulate carbon carrier or the like) on which a catalyst is supported, an electrolyte, and a dispersion solvent (organic solvent) to produce a catalyst solution (catalyst ink). The catalyst layer is formed by stretching this on a base material such as the electrolyte membrane 1 or the gas diffusion layer 4 in a layer shape with a coating blade to form a coating film and drying it in a hot air drying furnace or the like. Here, the electrolyte forming the catalyst solution is a proton conductive polymer, an ion exchange resin having a skeleton of an organic fluorine-containing polymer, such as a perfluorocarbon sulfonic acid resin, a sulfonated polyether ketone, a sulfonated polyether. Sulfonated plastic electrolytes such as sulfone, sulfonated polyetherethersulfone, sulfonated polysulfone, sulfonated polysulfide, sulfonated polyphenylene, sulfoalkylated polyetheretherketone, sulfoalkylated polyethersulfone, sulfoalkylated polyetherethersulfone And sulfoalkylated plastic electrolytes such as sulfoalkylated polysulfone, sulfoalkylated polysulfide, and sulfoalkylated polyphenylene. Examples of commercially available materials include Nafion (registered trademark, manufactured by DuPont) and Flemion (registered trademark, manufactured by Asahi Glass Co., Ltd.). Examples of the dispersion solvent include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, ethylene glycol, and diethylene glycol, acetone, methyl ethyl ketone, dimethylformamide, dimethylimidazolidinone, dimethyl sulfoxide, dimethylacetamide, and N-methylpyrrolidone. , Propylene carbonate, esters such as ethyl acetate and butyl acetate, and various aromatic or halogen solvents, and these can be used alone or as a mixed solution. Furthermore, regarding a conductive carrier carrying a catalyst, examples of the conductive carrier include carbon materials such as carbon black, carbon nanotubes, and carbon nanofibers, and carbon compounds typified by silicon carbide. As this catalyst (metal catalyst), for example, any one of platinum, platinum alloy, palladium, rhodium, gold, silver, osmium, iridium, etc. can be used, preferably platinum or platinum alloy is used. It is good to do. Furthermore, as this platinum alloy, for example, platinum, aluminum, chromium, manganese, iron, cobalt, nickel, gallium, zirconium, molybdenum, ruthenium, rhodium, palladium, vanadium, tungsten, rhenium, osmium, iridium, titanium and lead An alloy with at least one of them can be mentioned.

  The gas diffusion layer 4 for diffusing and providing the oxidant gas and fuel gas flowing through the gas flow path layer 5 to the membrane electrode assembly 3 includes a diffusion layer base material 41 and a current collecting layer 42 (MPL). The diffusion layer base material 41 is not particularly limited as long as it has a low electrical resistance and can collect current. For example, a material mainly composed of a conductive inorganic substance can be cited. Examples of the conductive inorganic substance include a fired body from polyacrylonitrile, a fired body from pitch, carbon materials such as graphite and expanded graphite, nanocarbon materials thereof, stainless steel, molybdenum, titanium, and the like. The form of the conductive inorganic substance of the diffusion layer base material 41 is not particularly limited. For example, the conductive inorganic substance is used in the form of fibers or particles, but is an inorganic conductive fiber from the viewpoint of gas permeability. Fiber is preferred. As the diffusion layer base material 41 using inorganic conductive fibers, a woven fabric or non-woven fabric structure can be used, and examples thereof include carbon paper and carbon cloth. The woven fabric is not particularly limited, such as plain weaving, crest weaving, and binding weaving, and examples of the nonwoven fabric include those made by a papermaking method, a needle punching method, and a water jet punching method. Further, examples of the carbon fiber include phenol-based carbon fiber, pitch-based carbon fiber, polyacrylonitrile (PAN) -based carbon fiber, and rayon-based carbon fiber. Further, the current collecting layer 42 serves as an electrode for collecting electrons from the catalyst layers 2 and 2 on the anode side and the cathode side, and is made of platinum, palladium, ruthenium, rhodium, iridium, gold, silver, which are conductive materials. , Copper and their compounds or alloys, conductive carbon materials, and the like.

  The protective film 6 is made of polytetrafluoroethylene, PVDF (polyvinyl difluoride), polyethylene, polyethylene naphthalate (PEN), polycarbonate, polyphenylene ether (PPE), polypropylene, polyester, polyamide, copolyamide, polyamide elastomer, polyimide. , Polyurethane, polyurethane elastomer, silicone, silicone rubber, silicon-based elastomer and the like.

  In addition, the gasket 8 provided in a region defined by the separator 7 and the electrode body 10 at the periphery of the electrode body accommodates the electrode body in, for example, a molding die, and injection-molds a resin at the periphery. Molded. Here, the gasket 8 is formed of a resin material such as butyl rubber, urethane rubber, silicone RTV rubber, epoxy resin having methanol resistance, epoxy-modified silicone resin, silicone resin, fluorine resin, or hydrocarbon resin. The

  Further, the separator 7 is interposed between the cathode side plate 71, the anode side plate 73, and the plates 71, 73 that define the cells between adjacent fuel cells, and And a spacer 72 formed in a frame shape (endless shape) along the outer periphery contour. The plates 71 and 73 are made of a conductive metal such as stainless steel or titanium, and the spacer 72 is made of the same conductive metal or resin. In one embodiment, a large number of dimples are provided on the side surface of the plate 71 facing the plate 73, and the dimple has a height corresponding to the thickness of the spacer 72, resulting in a three-layer structure. In some cases, the tip of the dimple is brought into contact with the side surface of the plate 73 to form a coolant channel. As another form, there is a form in which a linear or meandering refrigerant flow path is formed in the spacer 72. In this three-layer structure separator, a unique manifold M is formed in which each of fuel gas, oxidant gas, and refrigerant flows into the separator and then flows out, and is in fluid communication with the manifold M formed coaxially with the gasket 8. is doing. In addition, the endless rib 81 is formed in the periphery of the manifold M among the gaskets 8, and the fluid seal structure is formed when the separator 7 presses this.

  The gas flow path layer 5 shown in FIG. 1 is formed from expanded metal. This is done by continuously extruding a metal plate on a rotating roll, intermittently performing shearing, and then stretching the metal plate (metal mesh) after shearing to form pores such as trapezoids and rhombuses. The expanded metal 5 is formed. When viewed in a longitudinal section, the metal mesh that defines the pores has a state in which the inclined metal beams 51,... (The end surface of the metal beam 51 becomes the edge 51a) are arranged intermittently as shown in the figure. (Although not shown, when viewed from a direction orthogonal to the figure, a large number of pores defined in a trapezoidal or rhombus shape can be visually recognized by a metal beam).

  On the other hand, on the porous body side end surfaces of the diffusion layer base materials 41, 41 on the anode side and the cathode side, protrusions 41a projecting toward the expanded metal side at positions corresponding to the end surface edges 51a of the respective metal beams 51 of the expanded metal 5 described above. Is provided. Therefore, as shown in the drawing, each protrusion 41a has a posture in which the corresponding end surface edge 51a is supported. When stacking, a compressive force acts on each fuel cell 100, and when this acts on the diffusion layer base material 41 as a concentrated load from the end face edge 51a, the concentrated load is directly received by the protrusion 41a. Can be dispersed and transmitted to the diffusion layer substrate 41. The concentrated load does not act directly on the diffusion layer base material 41, and the dispersed dispersion load acts evenly. Further, the load dispersion is further performed on the diffusion layer base material 41, so that the diffusion layer is diffused. It is possible to effectively suppress the occurrence of cracks in the constituent members of the electrode body 10 including the layer base material 41.

  In the illustrated example, the protrusion 41a is provided on the diffusion layer base materials 41, 41 on both the anode side and the cathode side. However, depending on the conditions such as the compressive force acting and the thickness of the diffusion layer base material, the anode side Alternatively, the protrusion 41a may be provided only on one of the diffusion layer base materials 41 on the cathode side.

  The illustrated fuel cell 100 is stacked in the number corresponding to the required power (for example, 200 to 400) to form a cell stack, end plates are arranged on both sides, and tension plates, insulators, and the like are stacked. The fuel cell is formed by stacking with a given compressive force. A fuel cell system mounted on an electric vehicle or the like includes this fuel cell, various tanks for storing hydrogen gas and air, a blower for supplying these gases to the fuel cell, a radiator for cooling the fuel cell, a fuel The battery is generally composed of a battery that stores electric power generated by the battery, a drive motor that is driven by the electric power, and the like.

  FIG. 2 is a longitudinal sectional view showing another embodiment of the fuel cell.

  In this fuel cell 100A, the gas diffusion layer on the anode side is composed only of the current collecting layer 42A, and projections 42Aa,... Are provided on the side of the expanded metal 5 of the current collecting layer 42A. The end face edge 51a of the beam 51 is supported.

  Here, the cathode-side current collecting layer 42 is a slurry whose viscosity is adjusted by sufficiently stirring and mixing a conductive carbon powder and a water-repellent fluororesin (such as tetrafluoroethylene resin (PTFE)) emulsion. Is applied to the diffusion layer base material 41 on the cathode side, then dried in a high temperature atmosphere of about 100 ° C., and further fired at 300 ° C. or higher.

  On the other hand, the current collecting layer 42A on the anode side is processed into a sheet (or film) having rigidity and flexibility enough to be self-supporting because it does not have a diffusion layer base material. Is hot-pressed onto the catalyst layer 2. Even in the case of producing a film-like current collecting layer, a slurry of the same material as described above is poured into a mold having a sheet having a predetermined thickness and a cavity in which a protrusion 42Aa can be formed at a predetermined position on the surface thereof. It can be manufactured by firing.

  According to the fuel cell 100A shown in FIG. 2, since the anode side diffusion layer base material 41 is omitted, the cell thickness can be made as thin as possible, which can contribute to the miniaturization of the fuel cell.

  Depending on the compression force at the time of stacking, the thickness of the diffusion layer base material 41, the material, and other conditions, as a modification of the fuel cell shown in FIG. 2, the cathode side diffusion layer base material 41 does not have a protrusion 41a. A battery cell may be sufficient.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. They are also included in the present invention.

It is a longitudinal cross-sectional view of one embodiment of the fuel cell constituting the fuel cell of the present invention. It is a longitudinal cross-sectional view of other embodiment of the fuel cell which comprises the fuel cell of this invention. In the conventional fuel cell, it is the figure explaining the state which the porous body which consists of an expanded metal has pierced the diffusion layer base material.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electrolyte membrane, 2 ... Catalyst layer, 3 ... Membrane electrode assembly (MEA), 4 ... Gas diffusion layer, 41 ... Diffusion layer base material, 41a ... Protrusion, 42, 42A ... Current collection layer (MPL), 42Aa ... Projection, 5 ... Gas flow path layer (porous body, expanded metal), 51 ... Metal beam, 51a ... End face edge, 6 ... Protective film, 7 ... Separator, 71 ... Cathode side plate, 72 ... Intermediate plate (spacer), 73 ... Anode side plate, 8 ... Gasket, 81 ... Endless rib, 10 ... Electrode body (MEGA), 100, 100A ... Fuel cell, M ... Manifold

Claims (3)

An electrode body is formed from a membrane electrode assembly and an anode-side and cathode-side gas diffusion layer sandwiching the membrane-electrode assembly, and a porous body and a separator that form a gas flow path layer sandwich the electrode body to form a fuel cell. In a fuel cell formed by stacking the fuel cells,
The gas diffusion layer is formed of a current collecting layer in contact with the catalyst layer constituting the membrane electrode assembly and a diffusion layer base material surrounding the current collecting layer,
A fuel cell, wherein protrusions projecting toward the porous body are formed at locations where the diffusion layer base material contacts a plurality of edges of the end face of the porous body. A membrane electrode assembly, a gas diffusion layer composed of a current collection layer and a diffusion layer base material disposed on either the anode side or the cathode side sandwiching the membrane electrode assembly, and a current collection layer disposed on the other side, In the fuel cell in which the electrode body is formed, the porous body forming the gas flow path layer and the separator sandwich the electrode body to form a fuel battery cell, and the fuel battery cell is laminated.
Of the current collector layer disposed on the diffusion layer base material and the other side, at least a current collector layer disposed on the other side protrudes toward the porous body side at a location where it contacts a plurality of edges of the end surface of the porous body. A fuel cell having protrusions formed thereon.   The fuel cell according to claim 1, wherein the porous body is made of expanded metal.

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