JP5086581B2 - Fuel cell stack - Google Patents

Description

  The present invention relates to a fuel cell stack in which a plurality of single cell batteries each having an electrolyte membrane sandwiched between a fuel electrode and an oxidant electrode are stacked, and an external manifold for supplying a reaction gas is provided around the cell.

  A fuel cell is a power generator that supplies a fuel gas, such as hydrogen, and an oxidant gas, such as air, to the cell body to cause an electrochemical reaction, converting the chemical energy of the fuel directly into electrical energy and taking it out. Device. A fuel cell is highly evaluated as a power generation device that has high power generation efficiency and emits less pollutants and emits less noise.

  Such a fuel cell is basically configured by sandwiching an electrolyte membrane between a fuel electrode and an oxidant electrode, but a solid polymer using a proton conductive solid polymer membrane as an electrolyte layer. Since the fuel cell can be operated at a relatively low temperature, has a short start-up time, and has a large output density, it is attracting much attention as a stationary power source, an in-vehicle power source, and a portable power source.

  Here, an example of a polymer electrolyte fuel cell will be described. First, by disposing an electrically conductive separator with a gas flow path on both sides of a membrane electrode assembly (MEA) having an electrolyte membrane sandwiched between a fuel electrode and an oxidant electrode, a single cell A battery is formed. A fuel cell stack is obtained by holding both ends of a laminate in which a plurality of single cell batteries are laminated with end plates, passing a plurality of studs through holes penetrating both end plates, and tightening the laminate via a spring. Is configured.

  It is necessary to uniformly supply the fuel (hydrogen), the oxidant (air) necessary for the reaction, and the cooling water necessary for the cooling to each single cell battery of the fuel cell stack, and recover this after the reaction. As described above, there are an internal manifold system and an external manifold system as manifolds for distributing and collecting the reaction gas / cooling water.

  In the internal manifold system, gas / cooling water supply / discharge internal manifolds are provided at the periphery of the membrane electrode assembly and separator constituting the single cell battery, and the separator gas flow path / cooling water flow path Communicate. The internal manifolds are stacked to form a distribution / recovery manifold. The distribution / recovery manifold passes through the current collector plate and the end plate, and communicates with a pipe provided on the end plate.

  In the external manifold system, the gas flow passage provided in the separator is extended to the end of the separator and opened on the side surface of the laminated body, and separate external manifolds are arranged and distributed on the four side surfaces of the laminated body. In such an external manifold system, since the separator does not include a manifold, the size is equivalent to the effective area of the membrane electrode assembly, and the separator can be made compact, which is advantageous for cost reduction.

  Further, since an inexpensive insulating plastic can be used for the external manifold, the cost increase can be minimized. The volume of the external manifold can also be set without being restricted by the size of the separator, and gas and cooling water can be evenly distributed by the gas / cooling water flow passage of each single cell battery constituting the laminate. It becomes.

JP-A-7-254427 JP 2006-40807 JP 2001-93563 A

  By the way, in the case of the external manifold system, it is necessary to match the dimension of the external manifold with the dimension of the side surface of the laminated body, and it is particularly difficult to install according to the height of the laminated body. In addition, the external manifold and the side surface of the laminated body need to be sealed with a sealing material, and the external manifold and the side surface of the laminated body must be securely fixed.

  Such external manifold fixing methods include a method of fixing the external manifolds with bolts (see Patent Document 1), a method of fastening with wires (see Patent Document 2), and a method of fixing the external manifold to a clamping plate. (See Patent Document 3).

  In the method of fixing the external manifolds with bolts or wires, the inner dimension of the opening of the external manifold may be set wider than the groove opening range on the side surface of the laminate, and the fixing position is not limited. However, since it is not directly fixed to the laminate, it is difficult to absorb the dimensional change of the seal material of the external manifold on the four side surfaces. On the other hand, in the method of fixing the external manifold to the fastening plate, the dimensional change of the seal material of the external manifold can be absorbed independently. However, it is necessary to adjust the fixing position of the external manifold.

  The present invention has been proposed in order to solve the above-described problems of the prior art, and the object of the present invention is to reliably absorb the dimensional change of the seal material of the external manifold, and to match the height of the laminate, An object of the present invention is to provide a fuel cell stack capable of adjusting the fixed position of an external manifold.

  In order to achieve the above object, the present invention provides a basic battery comprising a unit cell in which an electrolyte is sandwiched between a pair of electrodes, and a separator provided at a position in contact with the electrodes and provided with a reaction gas flow path. A fuel comprising: an end plate configured by laminating a plurality of elements to constitute a laminated body; and clamping and holding both ends of the laminated body; and an external manifold arranged on a side surface of the laminated body and communicating with the reaction gas flow passage In the battery stack, the external manifold is fixed to the end plate, and the external manifold or the end plate is provided with a slide mechanism capable of adjusting a fixing position according to the length of the stacked body. Features.

  In the present invention as described above, since the position of the external manifold relative to the end plate can be adjusted by the slide mechanism, even when a sealing material or the like is interposed, or when the height of the laminated body changes due to individual differences, Dimensional changes can be absorbed and the external manifold can be securely fixed.

  As described above, according to the present invention, there is provided a fuel cell stack that can reliably absorb the dimensional change of the seal material of the external manifold and can easily adjust the fixing position of the external manifold according to the height of the stacked body. Can be provided.

  Hereinafter, embodiments of the fuel cell stack of the present invention (hereinafter referred to as embodiments) will be described with reference to the drawings.

[First Embodiment]
[Constitution]
The configuration of the present embodiment will be described with reference to FIGS. First, as shown in FIG. 1, the single cell battery includes a membrane / electrode assembly (MEA) 1, an oxidant separator 2, and a fuel / cooling water separator 3. An oxidant gas flow passage 21 is provided on the surface of the oxidant separator 2, and an end thereof opens to the side surface of the oxidant separator 2. A fuel gas flow passage 31 is provided on one surface of the fuel / cooling water separator 3, and a cooling water flow passage 32 is provided on the other surface. Is open.

  A plurality of such single cell batteries are stacked to form a stacked body. End plates 4 are arranged at both ends in the longitudinal direction of the laminate. The end plate 4 includes an insulating outer plate 41 and a conductive inner plate 42. The insulating external plate 41 is made of a heat-resistant resin material such as an epoxy resin, a vinyl ester resin, or a phenol resin, and is provided with a concave recess 43 on the inner side corresponding to the battery reaction part. Protrusions 44 are provided at the corners of the insulating external plate 41. A hole is provided at the center of the projection 44, and both ends of the fastening stud 5 are passed through the hole, and the end plate 4 sandwiching the laminated body is fastened by the fastening spring 51.

  The conductive inner plate 42 is a single flat plate (current collector plate) made of a conductive material such as stainless steel, and is disposed in the recess 43 of the insulating outer plate 41. An opening 45 is provided at the center of the recess 43, and the structure is configured to extract the generated current of the laminated body to the outside. Further, a plurality of fixing screw holes 46 for fixing a manifold, which will be described later, are provided on the side surface of the end plate 4.

  As shown in FIG. 2, an oxidant inlet / cooling water outlet external manifold 61, an oxidant outlet / cooling water inlet external manifold 62, a fuel inlet external manifold 63, and a fuel outlet external manifold 64 are provided on each side surface of the laminate. Has been placed. Each of these external manifolds 61 to 64 communicates with the oxidant gas flow path, the fuel gas flow path, and the cooling water flow path, and supplies and discharges fuel / oxidant gas necessary for the reaction to the membrane electrode assembly, A predetermined amount of cooling water is supplied to cool the heat generated by the reaction. In the figure, 61a is an oxidant inlet, 62a is an oxidant outlet, 62b is a cooling water inlet, 61b is a cooling water outlet, 63a is a fuel inlet, and 64a is a fuel outlet.

  A step is provided at the end corresponding to the end plate 4 of each of the external manifolds 61 to 64, and a slide mechanism long hole 65 is formed in the step as shown in FIG. Then, the external bolts 61 to 64 are fixed to the end plate 4 by screwing the fixing bolt (fixing tool) 7 through the slide mechanism long hole 65 into the fixing screw hole 46.

  A space between each of the external manifolds 61 to 64 and the side surface of the end plate 4 is sealed with a manifold seal material 8. A spring washer 71 is inserted between the fixing bolt 7 and each of the external manifolds 61 to 64 so that the tightening force is maintained even if the manifold seal material 8 undergoes dimensional changes due to aging. Has been.

  The seal width (X) of the end plate 4 is set to be larger than the seal width (Y) of each of the external manifolds 61 to 64, the thickness dimensions of the unit cells S constituting the laminate vary, and the laminate height changes. However, it can be sealed reliably. On the other hand, a slide mechanism long hole 65 into which a fixing bolt 7 for fixing the end plate 4 is inserted is provided outside the manifold seal portion of the end plate 4, and the fixing positions of the external manifolds 61 to 64 are within the range. It can be adjusted within the range of the width of the slide mechanism long hole 65 shown in FIG.

The range (b) is the movable range (a) of the manifold seal position relative to the end plate seal position, that is, the seal width (X) of the end plate 4 and the seal width ( Y) is set larger than the difference.
b ≧ a = XY (1)

Furthermore, as shown in the following equation (2), the outer portion (d) of the sliding range of the outer manifolds 61 to 64 is a clearance (inside the seal portion of the end plate 4 and the inner clearance of the seal portion of the outer manifolds 61 to 64). It is set smaller than c).
c ≧ d Formula (2)

[Function and effect]
According to the present embodiment as described above, due to the relationship of the formula (1), even if the height of the laminate changes due to individual differences, dimensional changes can be absorbed within the range of the seal movable range (a). Thus, by increasing the slide range (b) of the external manifolds 61 to 64, the external manifolds 61 to 64 can be reliably fixed.

  Further, due to the relationship of the expression (2), the above clearance is always kept positive within the adjustment range of the external manifolds 61 to 64, and the inside of the seal portion of the external manifolds 61 to 64 is inside the seal portion of the end plate 4, That is, it is possible to prevent the groove of the gas / cooling water flow passage that is necessarily located outside the unit battery S of the laminated body and opened on the side surface of the laminated body from being blocked.

[Second Embodiment]
[Constitution]
The configuration of the present embodiment will be described with reference to FIGS. The basic configuration of this embodiment is the same as that of the first embodiment. However, as shown in FIG. 4, a plurality of slide mechanism long holes 47 are provided on the side surface of the end plate 4. As shown in FIG. 5, the slide mechanism long hole 47 is for fixing each of the external manifolds 61 to 64, and the fixing portion has the following structure.

  That is, as shown in FIGS. 6A and 6B, fixing claws (fixing protrusions) 66 are provided at both ends of each of the external manifolds 61 to 64. The fixing claw 66 is inserted into the slide mechanism long hole 47 on the side surface of the end plate 4. A saw-like groove 47a in a direction parallel to the thickness is formed inside the long hole 47 for the slide mechanism, and an engaging portion with which the sharpened end of the fixing claw 66 engages with the groove 47a. It is configured to be fixed at an arbitrary position. A manifold seal member 8 and a spring washer 71 are inserted between the end plate 4 and the external manifolds 61 to 64 as in the first embodiment. The setting of the seal width (X) of the end plate 4 and the seal width (Y) of the external manifolds 61 to 64 is the same as in the first embodiment.

  And the fixed position of the external manifolds 61-64 can be adjusted in the range of the width | variety of the long hole 47 for slide mechanisms shown by the range (b). The range (b) is set larger than the movable range (a) of the manifold seal position relative to the end plate seal position, that is, the difference between the seal width (X) of the end plate 4 and the seal width (Y) of the external manifolds 61 to 64. (Similar to equation (1)).

  Further, in the sliding range of the outer manifolds 61 to 64, the inner part (d) is set smaller than the clearance (c) between the inside of the seal part of the end plate 4 and the inside of the seal part of the outer manifolds 61 to 64. (Similar to equation (2)).

[Function and effect]
According to the present embodiment as described above, the same operational effects as those of the first embodiment can be obtained by the relationship between the expressions (1) and (2). Further, since the external manifolds 61 to 64 are fixed using the fixing claws 66 instead of the fixing bolts 7, there is no need for bolt tightening, and the mounting of the external manifolds 61 to 64 can be realized with one touch. Therefore, the time for mounting the external manifolds 61 to 64 can be greatly reduced, which contributes to a reduction in stack manufacturing cost.

[Third Embodiment]
[Constitution]
The configuration of the present embodiment will be described with reference to FIGS. The basic configuration of this embodiment is the same as that of the first embodiment. However, as shown in FIGS. 7 and 8, the external manifolds 61 to 64 and the end plate 4 are fixed with a metal buckle 9 via a manifold seal material 8. The buckle 9 is provided with a spring property, and maintains the tightening force even if there is a dimensional change due to aging deterioration of the manifold seal material 8. The buckle 9 is attached to a protruding portion on the surface of the end plate 4 and can be freely rotated by a hinge mechanism. The setting of the seal width (X) of the end plate 4 and the seal width (Y) of the external manifolds 61 to 64 is the same as in the first embodiment.

  And the fixed position of the external manifolds 61-64 can be adjusted in the range of the width | variety of the hollow 67 for slide mechanisms which the edge part of the buckle shown by the range (b) contacts. The range (b) is set larger than the movable range (a) of the manifold seal position relative to the end plate seal position, that is, the difference between the seal width (X) of the end plate 4 and the seal width (Y) of the external manifolds 61 to 64. (Similar to equation (1)).

  Further, in the sliding range of the outer manifolds 61 to 64, the outer portion (d) is set to be smaller than the clearance (c) between the inside of the seal portion of the end plate 4 and the inside of the seal portion of the outer manifolds 61 to 64. (Similar to equation (2)).

[Function and effect]
According to the present embodiment as described above, the same operational effects as those of the first embodiment can be obtained by the relationship between the expressions (1) and (2). In addition, since the external manifolds 61 to 64 are fixed using the buckle 9 instead of the fixing bolt 7, there is no need for bolt tightening, and the rotation of the buckle 9 allows the external manifolds 61 to 64 to be touched one-touch. Mounting can be realized. Furthermore, since it fastens with the buckle 9 from the outer side of the external manifolds 61-64, alignment becomes easy. Therefore, the time for mounting the external manifolds 61 to 64 can be greatly reduced, which contributes to a reduction in stack manufacturing cost.

[Other Embodiments]
The present invention is not limited to the embodiment as described above. For example, the size, quantity, material, shape, etc. of each member can be freely changed. The present invention is not limited to solid polymer fuel cells, and can be widely applied to fuel cell stacks that require similar manifolds.

The perspective view which shows the laminated body of the fuel cell stack of the 1st Embodiment of this invention. The perspective view which shows the fuel cell stack of embodiment of FIG. 1 is a cross-sectional view of the fuel cell stack according to the embodiment of FIG. The perspective view which shows the laminated body of the fuel cell stack of the 2nd Embodiment of this invention. The perspective view which shows the fuel cell stack of embodiment of FIG. 4A is a longitudinal sectional view of the fuel cell stack of the embodiment of FIG. The perspective view which shows the fuel cell stack of the 3rd Embodiment of this invention. Sectional drawing of the fuel cell stack of embodiment of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Membrane electrode assembly 2 ... Oxidant separator 3 ... Fuel / cooling water separator 4 ... End plate 5 ... Tightening stud 7 ... Fixing bolt 8 ... Manifold seal material 9 ... Buckle 21 ... Oxidant gas flow passage 31 ... Fuel gas flow path 32 ... Cooling water flow path 41 ... Insulating outer plate 42 ... Conductive inner plate 43 ... Depression 44 ... Protrusion 45 ... Opening 46 ... Fixing screw holes 47, 65 ... Sliding mechanism long hole 47a ... Groove 51 ... Clamping spring 61 ... Oxidant inlet / cooling water outlet external manifold 62 ... Oxidant outlet / cooling water inlet external manifold 63 ... Fuel inlet external manifold 64 ... Fuel outlet external manifold 64
61a ... Oxidant inlet 62a ... Oxidant outlet 62b ... Cooling water inlet 61b ... Cooling water outlet 63a ... Fuel inlet 64a ... Fuel outlet 66 ... Fixing claw 71 ... Spring washer

Claims (5)

A plurality of basic elements constituted by a unit battery in which an electrolyte is sandwiched between a pair of electrodes and a separator provided at a position in contact with the electrodes and provided with a reaction gas flow path are laminated to form a laminate. In a fuel cell stack comprising an end plate that clamps and holds both ends of the laminate, and an external manifold that is disposed on a side surface of the laminate and communicates with the reaction gas flow path.
The external manifold is fixed to the end plate;
The fuel cell stack, wherein the external manifold or the end plate is provided with a slide mechanism capable of adjusting a fixing location in accordance with the length of the stacked body. A fixture for fixing the outer manifold to the end plate;
2. The fuel cell stack according to claim 1, wherein the slide mechanism has a long hole that is provided in the external manifold and through which the fixture is inserted.   2. The slide mechanism according to claim 1, wherein the slide mechanism includes a fixing protrusion provided on the external manifold, and an engaging portion provided on the end plate and engaged with the fixing protrusion. Fuel cell stack.   The fuel cell stack according to claim 1, wherein the slide mechanism has a buckle provided on an end plate. A plurality of basic elements constituted by a unit battery in which an electrolyte is sandwiched between a pair of electrodes and a separator provided at a position in contact with the electrodes and provided with a reaction gas flow path are laminated to form a laminate. In a fuel cell stack comprising an end plate that clamps and holds both ends of the laminate, and an external manifold that is disposed on a side surface of the laminate and communicates with the reaction gas flow path.
The external manifold is fixed to the end plate;
The external manifold is provided with a slide mechanism that can adjust the fixing location according to the length of the laminate,
A fixture for fixing the outer manifold to the end plate;
The slide mechanism is provided in a portion protruding by a step at the end of the external manifold, and has a long hole through which the fixture is inserted,
On the side surface of the end plate, there is provided a protrusion provided with a hole through which a fastening stud for fastening and fixing the end plates at both ends of the laminated body to each other is provided,
The seal width determined by the thickness other than the protrusion on the side surface of the end plate, and the seal width determined by the thick portion other than the portion protruding due to the step among the portions overlapping the end plate in the manifold . The fuel cell stack is characterized in that the difference is set smaller than the adjustment width of the slide mechanism.

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