JP5430518B2 - Fuel cell stack - Google Patents

Description

  The present invention includes a fuel cell in which an electrolyte membrane / electrode structure provided with a pair of electrodes on both sides of an electrolyte membrane and a rectangular separator are stacked, and a stacking direction of the stack in which a plurality of the fuel cells are stacked A pair of end plates are disposed at both ends, and the long sides of the pair of end plates relate to a fuel cell stack fixed by a fastening member.

  For example, in a polymer electrolyte fuel cell, an electrolyte membrane / electrode structure (MEA) in which an anode side electrode and a cathode side electrode are disposed on both sides of an electrolyte membrane made of a polymer ion exchange membrane is sandwiched by separators. Unit cell (power generation cell). This type of fuel cell is usually used as an in-vehicle fuel cell stack or the like by stacking a predetermined number of unit cells.

  In this type of fuel cell stack, it is necessary to apply a good tightening load to the stacking direction in order to obtain a desired power generation performance and to exert a sealing function. In addition, particularly in a fuel cell stack for in-vehicle use, a load (impact force) may be applied from the outside during traveling or the like, and it is necessary to prevent positional deviation in a direction intersecting the stacking direction of unit cells.

  Therefore, for example, a fuel cell stack disclosed in Patent Document 1 is known. As shown in FIG. 7, this fuel cell stack has an end plate 1a, an insulating plate 2a, a current collecting plate 3a, a plurality of unit cells 4, a current collecting plate 3b, an insulating plate 2b, and an end plate 1b in this order. Has been. In order to apply a load in the stacking direction between the end plates 1a and 1b, square columnar fastening members 5 are fixed to the four corners of the end plates 1a and 1b.

  The fuel cell stack includes four external restraining members 6a, 6b, 6c and 6d extending in the stacking direction. At the center of each of the upper long side, the lower long side, the left short side, and the right short side of the end plates 1a, 1b, insulating plates 2a, 2b, current collecting plates 3a, 3b and the stacked unit cells 4 Recesses 7a, 7b, 7c and 7d into which the external restraining members 6a, 6b, 6c and 6d are fitted are formed.

JP 2009-70674 A

  In Patent Document 1, four fastening members 5 are fixed between end plates 1a and 1b, and four external restraining members 6a to 6d are fixed to the end plates 1a and 1b. For this reason, there is a problem that the number of parts considerably increases and the cost increases. Moreover, there is a problem that the assembly work of the fuel cell stack becomes complicated.

  The present invention solves this type of problem, and an object thereof is to provide a fuel cell stack that can reliably receive an external load applied to the fuel cell with a simple configuration and a small number of parts. .

  The present invention includes a fuel cell in which an electrolyte membrane / electrode structure provided with a pair of electrodes on both sides of an electrolyte membrane and a rectangular separator are stacked, and a stacking direction of the stack in which a plurality of the fuel cells are stacked A pair of end plates are disposed at both ends, and the long sides of the pair of end plates relate to a fuel cell stack fixed by a fastening member.

In this fuel cell stack, convex portions are respectively formed on both side surfaces in the stacking direction of the laminate on which the respective fastening members are arranged, and the fastening members are provided with fitting portions that fit into the convex portions. The fitting portion receives a load in the long side direction of the end plate .

  In this fuel cell stack, it is preferable that the fastening member is provided with a reinforcing rib adjacent to the fitting portion and extending in the stacking direction.

  Further, in this fuel cell stack, the fastening member is provided at one end portion on one end plate side with a bent portion that bends in the surface direction of the one end plate, and on the other end portion on the other end plate side, It is preferable to provide a wide portion whose width is increased toward the long side of the other end plate.

According to the present invention, the fastening members that connect the long sides of the pair of end plates are provided with fitting portions that fit into the convex portions formed on both side surfaces in the stacking direction of the stack. For this reason, while each fastening member receives the load of a lamination direction, a fitting part can receive the load of the electric power generation surface direction which cross | intersects the said lamination direction.

  In addition, the number of parts is effectively reduced, and an external load applied to the fuel cell can be reliably received with a simple configuration.

1 is a schematic perspective view of a fuel cell stack according to an embodiment of the present invention. FIG. 3 is an exploded perspective view of a main part of the fuel cell stack. It is a partially exploded perspective view of the fuel cell stack. FIG. 4 is a cross-sectional view of the fuel cell stack taken along line IV-IV in FIG. 3. It is a principal part disassembled perspective explanatory drawing of the fuel cell which comprises the said fuel cell stack. FIG. 6 is a cross-sectional view of the fuel cell stack taken along line VI-VI in FIG. 1. 6 is a perspective explanatory view of a fuel cell stack of Patent Document 1. FIG.

  As shown in FIGS. 1 and 2, in the fuel cell stack 10 according to the embodiment of the present invention, a stacked body 14 is configured by stacking a plurality of fuel cells 12 in the direction of arrow A (vertical direction). A first terminal plate 16a, a first insulating plate 18a, and a first end plate (the other end plate) 20a are stacked on the lower end (one end) of the stacked body 14 in the stacking direction.

  As shown in FIGS. 1 to 3, a second terminal plate 16 b, a second insulating plate 18 b, a second end plate (one end plate) 20 b, and a pressurization are provided at the upper end (the other end) of the stacked body 14. The adjusting device 22 is stacked. The pressure adjusting device 22 includes a load measuring mechanism 24 and a pressure mechanism 26. The stacked body 14 may be configured by stacking a plurality of fuel cells 12 in the horizontal direction (arrow B direction or arrow C direction).

  As shown in FIG. 5, in the fuel cell 12, the electrolyte membrane / electrode structure 30 is sandwiched between rectangular first and second separators 32 and 34. The first and second separators 32 and 34 are made of, for example, a metal separator such as a steel plate, a stainless steel plate, an aluminum plate, or a plated steel plate, a carbon separator, or the like.

  One end edge of the fuel cell 12 in the direction of arrow B (the horizontal direction in FIG. 5) communicates with each other in the direction of arrow A, which is the stacking direction, and oxidant for supplying an oxidant gas, for example, an oxygen-containing gas An agent gas inlet communication hole 36a and a fuel gas inlet communication hole 38a for supplying a fuel gas, for example, a hydrogen-containing gas, are arranged in an arrow C direction (horizontal direction).

  The other end edge of the fuel cell 12 in the direction of arrow B communicates with each other in the direction of arrow A, a fuel gas outlet communication hole 38b for discharging fuel gas, and an oxidant gas for discharging oxidant gas. The outlet communication holes 36b are arranged in the direction of arrow C.

  A pair of cooling medium inlet communication holes 40a for supplying a cooling medium and a pair of cooling for discharging the cooling medium are provided at both ends of the fuel cell 12 in the direction of arrow C, that is, on each long side. A medium outlet communication hole 40b is provided.

  An oxidant gas flow path 42 communicating with the oxidant gas inlet communication hole 36a and the oxidant gas outlet communication hole 36b is provided on the surface 32a of the first separator 32 facing the electrolyte membrane / electrode structure 30.

  A fuel gas passage 44 communicating with the fuel gas inlet communication hole 38a and the fuel gas outlet communication hole 38b is provided on the surface 34a of the second separator 34 facing the electrolyte membrane / electrode structure 30.

  A cooling medium that connects the cooling medium inlet communication hole 40a and the cooling medium outlet communication hole 40b between the surface 32b of the first separator 32 and the surface 34b of the second separator 34 that constitute the fuel cells 12 adjacent to each other. A flow path 46 is provided.

  A first seal member 48 is integrally or individually provided on the surfaces 32 a and 32 b of the first separator 32, and a second seal member 50 is integrally formed on the surfaces 34 a and 34 b of the second separator 34. Or it is provided separately.

  The first and second seal members 48 and 50 are, for example, EPDM, NBR, fluoro rubber, silicon rubber, fluorosilicon rubber, butyl rubber, natural rubber, styrene rubber, chloroprene, or acrylic rubber or the like, cushion material, Alternatively, a packing material is used.

  The electrolyte membrane / electrode structure 30 includes, for example, a solid polymer electrolyte membrane 52 in which a perfluorosulfonic acid thin film is impregnated with water, and a cathode side electrode 54 and an anode side electrode 56 that sandwich the solid polymer electrolyte membrane 52. With.

  The cathode side electrode 54 and the anode side electrode 56 are formed by uniformly applying a gas diffusion layer made of carbon paper or the like and porous carbon particles carrying a platinum alloy on the surface thereof to the surface of the gas diffusion layer. An electrode catalyst layer. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 52.

  The first separator 32 is located between the pair of cooling medium inlet communication holes 40a and the pair of cooling medium outlet communication holes 40b at the center of each long side, that is, in the long side direction of the first separator 32. Convex portions 57a and 57b are formed, which are located substantially at the center of each of the projections and project outward. The second separator 34 is located between the pair of cooling medium inlet communication holes 40a and the pair of cooling medium outlet communication holes 40b at the center of each long side, that is, in the long side direction of the second separator 34 Convex portions 57c and 57d projecting outward are formed at substantially the center of each. The convex portions 57a to 57d may be formed integrally with the first and second separators 32 and 34 by a resin material, or may be joined separately.

  As shown in FIGS. 1 and 2, for example, a pair of fastening members 60 are bridged between first and second end plates 20a, 20b made of aluminum, and the first and second end plates 20a, 20b are laid. The distance between them is kept constant. For example, the fastening member 60 has a long plate shape made of aluminum, and one fastening member 60 is disposed on each long side of the fuel cell stack 10 (long side of the first and second end plates 20a and 20b). Is done. The fastening member 60 is configured in a bilaterally symmetric shape.

  The fastening member 60 is bent at one end portion on the second end plate 20b side in the surface direction of the second end plate 20b and is connected to the pressure adjusting device 22, specifically, the pressure mechanism 26. 62 is provided, and a wide portion 64 whose width dimension is enlarged toward the long side of the first end plate 20a is provided at the other end of the first end plate 20a.

  The fastening member 60 includes a main body portion 66 extending with the same width dimension between the long sides of the first and second end plates 20a and 20b. A pair of reinforcing plate portions 68 constituting the wide portion 64 are provided by extending in a direction away from each other toward both ends of the long side of the one end plate 20a. The main body 66 is set to a width dimension smaller than the long side dimension of the first and second end plates 20a, 20b, and the width center substantially coincides with the long side center of the first and second end plates 20a, 20b. To do.

  The pair of reinforcing plate portions 68 are inclined in a direction away from each other downward from the lower end edge of the main body portion 66, and the lower end portion of the reinforcing plate portion 68 is interposed between the main plate portion 70 and the horizontal plate portion 70. The lower end portion of the portion 66 is integrally connected. The main body portion 66 and the pair of reinforcing plate portions 68 are provided with at least one reinforcing rib 72.

  A fitting portion 73 is formed in the main body portion 66 in parallel with the reinforcing rib 72, that is, extending in the stacking direction (arrow A direction). The fitting portion 73 is formed to bulge outward from the fuel cell 12. As shown in FIG. 6, in one fastening member 60, the protrusions 57 a and 57 c of the fuel cell 12 are fitted in the fitting portion 73, and in the other fastening member 60, the fuel cell 12 is placed in the fitting portion 73. The convex portions 57b and 57d are fitted together.

  Contrary to the above, the convex portions 57a to 57d of the fuel cell 12 may be configured as concave portions, while the fitting portion 73 of the fastening member 60 may be configured as convex portions.

  As shown in FIG. 2, the main body portion 66 and the pair of reinforcing plate portions 68 are provided with screw holes 78 into which screws 76 to be inserted into holes 74 formed on the long side of the first end plate 20a are screwed. It is fixed to the first end plate 20a via the screw 76.

  The bent portion 62 includes a pair (three or more) of female screw portions 80 extending in the vertical direction. The female screw portions 80 are spaced apart from each other by a predetermined interval, and extend in the vertical direction so that a screw hole 80a is formed therethrough.

  As shown in FIG. 2, the first end plate 20a has an oxidant gas inlet communication hole 36a, a fuel gas inlet communication hole 38a, a cooling medium inlet communication hole 40a, an oxidant gas outlet communication hole 36b, and a fuel gas outlet communication hole. There are provided manifolds 82a to 82f communicating with 38b and the cooling medium outlet communication hole 40b and extending to the outside.

  As shown in FIG. 3, the second end plate 20b is configured in a flat plate shape, and the second end plate 20b has, for example, four cylindrical recesses 84 formed at four locations.

  As shown in FIGS. 3 and 4, the load measuring mechanism 24 includes a pair of connecting members 86 and a load sensor accommodated in the recess 84, for example, a load cell 88. Instead of the pair of connecting members 86, for example, a connecting member (not shown) configured by integrally joining a pair of connecting members into a frame shape may be used.

  A pressing member 90 is attached to the load cell 88, and the pressing member 90 is disposed in the recess 84. A spherical receiving portion 92 is provided on the load cell 88. At both ends of the connecting member 86, spherical concave portions 94 having a spherical bottom surface are provided at positions corresponding to the spherical receiving portions 92 (coaxial positions).

  The pressurizing mechanism 26 includes a plurality of, for example, four load adjustment bolts 96. Each load adjustment bolt 96 is screwed into a screw hole 80 a formed in the female thread portion 80 of the fastening member 60, and each spherical tip portion 96 a is disposed in each spherical recess 94 of the connecting member 86. The center of each load adjustment bolt 96 and the center of each load cell 88 are arranged at coaxial positions. A lock nut 98 is screwed onto the load adjustment bolt 96.

  The operation of the fuel cell stack 10 configured as described above will be described below.

  First, as shown in FIG. 5, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet communication hole 36a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 38a. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the cooling medium inlet communication hole 40a.

  Therefore, the oxidant gas is introduced into the oxidant gas flow path 42 of the first separator 32 from the oxidant gas inlet communication hole 36a. The oxidant gas is supplied to the cathode side electrode 54 constituting the electrolyte membrane / electrode structure 30 while moving in the arrow B direction.

  On the other hand, the fuel gas is introduced into the fuel gas flow path 44 of the second separator 34 from the fuel gas inlet communication hole 38a. The fuel gas is supplied to the anode side electrode 56 constituting the electrolyte membrane / electrode structure 30 while moving in the direction of arrow B.

  Therefore, in the electrolyte membrane / electrode structure 30, the oxidant gas supplied to the cathode side electrode 54 and the fuel gas supplied to the anode side electrode 56 are consumed by an electrochemical reaction in the electrode catalyst layer to generate power. Is done.

  Next, the oxidant gas consumed by being supplied to the cathode side electrode 54 is discharged in the direction of arrow A along the oxidant gas outlet communication hole 36b. On the other hand, the fuel gas consumed by being supplied to the anode side electrode 56 is discharged in the direction of arrow A along the fuel gas outlet communication hole 38b.

  The cooling medium supplied to the cooling medium inlet communication hole 40a is introduced into the cooling medium flow path 46 between the first and second separators 32 and 34, and then flows in the direction of arrow C. The cooling medium is discharged from the cooling medium outlet communication hole 40b after the electrolyte membrane / electrode structure 30 is cooled.

  In this case, in the present embodiment, a pair of fastening members 60 are spanned between the first and second end plates 20a, 20b, and when the load in the stacking direction is applied to the fuel cell stack 10, The load can be favorably received by the pair of fastening members 60.

  In addition, the fastening member 60 is fitted with fitting portions 73 that fit into convex portions 57a, 57c or 57b, 57d formed on both side surfaces of the laminate 14 in the stacking direction, specifically, both long sides of the fuel cell 12. Is provided.

  For this reason, as shown in FIG. 6, when a load (impact) G1 is applied to the fuel cell stack 10 in one of the long side directions (arrow B1 direction), the fitting portion 73 and the convex portion 57a of one fastening member 60 are provided. 57c and the fitting part 73 of the other fastening member 60 and the convex parts 57b, 57d can receive the load G1 satisfactorily.

  Further, when a load (impact) G2 is applied to the fuel cell stack 10 in the other long side direction (arrow B2 direction), similarly, each fitting portion 73 and the convex portions 57a and 57c and the convex portions 57b and 57d. Thus, the load G2 can be received well.

  Furthermore, when a load (impact) G3 is applied in the short side direction of the fuel cell stack 10, the load G3 can be satisfactorily received under the contact action of the pair of fastening members 60.

  In the fuel cell stack 10, one fastening member 60 is disposed on each long side of the fuel cell stack 10, but the present invention is not limited to this. For example, one fastening member 60 may be similarly disposed on each short side of the fuel cell stack 10.

  Therefore, in the present embodiment, the number of parts is effectively reduced, and the external load applied to the fuel cell 12 can be reliably received with a simple configuration. Thereby, there is an advantage that the laminated body 14 can be satisfactorily held at the time of collision, and the deterioration of the sealing performance can be prevented.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell stack 12 ... Fuel cell 14 ... Laminated body 16a, 16b ... Terminal plate 18a, 18b ... Insulating plate 20a, 20b ... End plate 22 ... Pressure adjusting device 24 ... Load measuring mechanism 26 ... Pressure mechanism 30 ... Electrolyte Membrane / electrode structure 32, 34 ... Separator 36a ... Oxidant gas inlet communication hole 36b ... Oxidant gas outlet communication hole 38a ... Fuel gas inlet communication hole 38b ... Fuel gas outlet communication hole 40a ... Cooling medium inlet communication hole 40b ... Cooling Medium outlet communication hole 42 ... Oxidant gas flow path 44 ... Fuel gas flow path 46 ... Cooling medium flow path 52 ... Solid polymer electrolyte membrane 54 ... Cathode side electrode 56 ... Anode side electrode 57a-57d ... Projection 60 ... Fastening member 62 ... Bending part 64 ... Wide part 66 ... Main body part 68 ... Reinforcing plate part 70 ... Horizontal plate part 72 ... Rib 73 ... Fitting part

Claims (3)

Provided with a fuel cell in which an electrolyte membrane / electrode structure provided with a pair of electrodes on both sides of an electrolyte membrane and a rectangular separator are stacked, and at both ends in the stacking direction of the stack in which a plurality of the fuel cells are stacked, A pair of end plates are disposed, and the long sides of the pair of end plates are each a fuel cell stack fixed by a fastening member,
On both side surfaces in the stacking direction of the laminate in which each fastening member is disposed, a convex portion is formed,
Wherein the fastening member, the fitting portion mating with the convex portion is provided, a fuel cell stack according to claim Rukoto under load in the long side direction of the end plate by the fitting portion.   2. The fuel cell stack according to claim 1, wherein the fastening member is provided with a reinforcing rib adjacent to the fitting portion and extending in the stacking direction. 3. The fuel cell stack according to claim 1, wherein the fastening member is provided with a bent portion that bends in the surface direction of the one end plate at one end portion on the one end plate side,
A fuel cell stack, characterized in that a wide portion whose width dimension is enlarged toward the long side of the other end plate is provided at the other end portion on the other end plate side.

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