JP5026616B2 - 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 separator are stacked, and a plurality of the fuel cells are stacked. The present invention relates to a fuel cell stack provided with an end plate.

  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. A unit cell is provided. This type of fuel cell is normally used as a fuel cell stack 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.

  Therefore, for example, in the fuel cell disclosed in Patent Document 1, as shown in FIG. 7, pressure plates 3a, 3b are disposed at both ends of a laminate in which a predetermined number of separators 1 and electrode units 2 are laminated. Is arranged. A holding member 4 having an L-shaped cross section is disposed at each corner of the pressure plate 3a, 3b, and the holding member 4 is fastened to the pressure plate 3a, 3b via a screw 5.

  In other words, a clamping load in the stacking direction is applied to the separator 1 and the electrode unit 2 via the four holding members 4 between the pressure plates 3a and 3b.

JP 2000-48850 A

  However, in the above-mentioned Patent Document 1, each holding member 4 and the pressure plates 3a and 3b are screws which are screwed through the holding member 4 into screw holes formed in the side portions of the pressure plates 3a and 3b. It is only fastened by 5.

  Therefore, when a load is applied to the fuel cell from the outside, the outer shape of the stack is likely to be deformed, the tightening load in the stacking direction cannot be maintained, and there is a problem that a load drop occurs. Moreover, there is a problem that the separator 1 and the electrode unit 2 are easily moved due to the deformation of the stack outer shape.

  The present invention solves this type of problem. A fuel cell stack that can reliably receive external loads and the like with a simple configuration and that can satisfactorily suppress deformation and loss of tightening loads. The purpose is to provide.

  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 separator are stacked, and a plurality of the fuel cells are stacked. The present invention relates to a fuel cell stack provided with an end plate.

  The fuel cell stack includes a connecting member that spans between a pair of end plates, a holding mechanism that is provided on a side surface of the end plate and the connecting member, and applies tension in a tightening direction. A fixing mechanism for fixing the side surface and the connecting member to each other is provided.

  The holding mechanism preferably includes at least a hole provided in the side surface of the end plate or the connecting member, and a pin member inserted into the hole.

  Furthermore, it is preferable that a reinforcing ring is press-fitted into the hole.

  Furthermore, it is preferable that a sealing member for sealing the pin member is disposed in the hole.

  In addition, the holding mechanism is provided on the side surface of the end plate, and on the connecting member, protrudes outward in the width direction of the connecting member, and straddles the protruding portion outward in the stacking direction. It is preferable to provide the protrusion part which unites.

  Furthermore, it is preferable that a spacer member for adjusting the dimension in the stacking direction is interposed between the protrusion and the protrusion.

  Furthermore, the fuel cell is provided with a fluid communication hole that communicates in the stacking direction and allows the reaction gas and the cooling medium to flow, and a connection portion between the connection member and the side surface of the end plate is provided at a position offset from the fluid communication hole. It is preferred that

  According to the present invention, tension is applied to the connecting member and the end plate in the tightening direction via the holding mechanism, and the fastening force between the connecting member and the end plate is maintained via the fixing mechanism. ing. Therefore, it is possible to reliably apply a desired tightening force with a simple configuration.

  Furthermore, when an external load is applied to the fuel cell stack, the connecting member can be prevented from peeling off under the action of the fixing mechanism. In addition, the connecting member can protect the fuel cell by receiving an external impact, and can prevent (bend) the fuel cell from being deformed.

1 is a schematic perspective explanatory view of a fuel cell stack according to a first embodiment of the present invention. It is a principal part disassembled perspective explanatory drawing of the fuel cell which comprises the said fuel cell stack. It is a disassembled perspective explanatory drawing from one of the holding mechanism and fixing mechanism which comprise the said fuel cell stack. It is an exploded perspective view from the other of the holding mechanism and the fixing mechanism. FIG. 5 is a perspective explanatory view of a fuel cell stack according to a second embodiment of the present invention. FIG. 3 is an exploded perspective view of a holding mechanism and a fixing mechanism that constitute the fuel cell stack. 2 is a perspective view of a fuel cell according to Patent Document 1. FIG.

  As shown in FIG. 1, the fuel cell stack 10 according to the first embodiment of the present invention includes a plurality of fuel cells 12 stacked in the direction of arrow A (vertical direction) and both ends of the fuel cells 12 in the stacking direction. Are provided with terminal plates 14a and 14b, insulating plates 16a and 16b and end plates 18a and 18b.

  As shown in FIG. 2, the fuel cell 12 includes an electrolyte membrane / electrode structure 20 sandwiched between first and second separators 22 and 24. The first and second separators 22 and 24 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, or a carbon separator.

  One end edge of the fuel cell 12 in the direction of arrow B (the horizontal direction in FIG. 2) 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 26a and a fuel gas inlet communication hole 28a 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, the fuel gas outlet communication hole 28b for discharging the fuel gas, and the oxidant gas for discharging the oxidant gas. Outlet communication holes 26b are arranged in the direction of arrow C.

  A cooling medium inlet communication hole 30a for supplying a cooling medium and a cooling medium outlet communication hole 30b for discharging the cooling medium are provided at both ends of the fuel cell 12 in the arrow C direction.

  An oxidant gas passage 32 communicating with the oxidant gas inlet communication hole 26a and the oxidant gas outlet communication hole 26b is formed on a surface 22a of the first separator (cathode side separator) 22 facing the electrolyte membrane / electrode structure 20. Provided.

A fuel gas flow path 34 communicating with the fuel gas inlet communication hole 28a and the fuel gas outlet communication hole 28b is provided on the surface 24a of the second separator ( anode side separator) 24 facing the electrolyte membrane / electrode structure 20.

  A cooling medium that connects the cooling medium inlet communication hole 30a and the cooling medium outlet communication hole 30b between the surface 22b of the first separator 22 and the surface 24b of the second separator 24 that constitute the fuel cells 12 adjacent to each other. A flow path 36 is provided.

  The first seal member 38 is integrally or individually provided on the surfaces 22 a and 22 b of the first separator 22, and the second seal member 40 is integrally formed on the surfaces 24 a and 24 b of the second separator 24. Or it is provided separately.

  The first and second sealing members 38 and 40 are, for example, EPDM, NBR, fluorine rubber, silicon rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene, or acrylic rubber or the like, cushioning material, Alternatively, a packing material is used.

  The electrolyte membrane / electrode structure 20 includes, for example, a solid polymer electrolyte membrane 42 in which a perfluorosulfonic acid thin film is impregnated with water, and a cathode side electrode 44 and an anode side electrode 46 that sandwich the solid polymer electrolyte membrane 42. With.

  The cathode side electrode 44 and the anode side electrode 46 are formed by uniformly applying a gas diffusion layer made of carbon paper or the like and porous carbon particles having a platinum alloy supported 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 42.

  As shown in FIG. 1, for example, a plurality of connecting members 50 are bridged between end plates 18a, 18b made of aluminum. The connecting member 50 has, for example, a long plate shape made of aluminum, and two connecting members 50 are arranged on the long side of the fuel cell stack 10 and one on the short side of the fuel cell stack 10. Is done.

  The arrangement position of the connecting member 50 is set at a position (offset position) separated from the cooling medium inlet communication hole 30a and the cooling medium outlet communication hole 30b on the long side, whereas the oxidant gas inlet is set on the short side. They are set between the communication hole 26a and the fuel gas inlet communication hole 28a and between the oxidant gas outlet communication hole 26b and the fuel gas outlet communication hole 28b.

  The fuel cell stack 10 is provided on the side surfaces 51a and 51b of the end plates 18a and 18b and the connecting member 50, and a holding mechanism 52 for applying tension in the tightening direction (arrow A direction), and the end plates 18a and 18b. The side surfaces 51a, 51b and the connecting member 50 are provided with a fixing mechanism 54 for fixing the side surfaces 51a, 51b to each other. With respect to the end plates 18a and 18b, the holding mechanism 52 and the fixing mechanism 54 of the connecting member 50 are configured identically.

As shown in FIGS. 3 and 4, the holding mechanism 52, the end plate 18a, side surface 51a of 18b, a first hole 56a formed in 51b, the second to be made form the upper and lower end portions of the connecting member 50 A hole 56b and a pin member 58 that is integrally inserted into the first and second holes 56a and 56b are provided. The pin member 58 is made of, for example, an iron-based material.

  Reinforcing rings 60a and 60b made of, for example, an iron-based material are press-fitted into the first and second holes 56a and 56b, and the pin member 58 is integrally inserted into the reinforcing rings 60a and 60b.

  The fixing mechanism 54 includes screw holes 62 provided on the side surfaces 51 a and 51 b of the end plates 18 a and 18 b on both sides of the first hole portion 56 a and screws 64 fastened to the screw holes 62.

  A pair of hole portions 66 are formed in the connecting member 50 corresponding to the screw holes 62. A pin cover 68 is disposed on the surface side of the connecting member 50, and screws 64 are inserted into a pair of holes 70 formed in the pin cover 68. The screws 64 pass through the holes 66. Then, the screw hole 62 is tightened.

  In the connecting member 50, seal grooves 72a and 72b are formed around both end openings of the second hole portion 56b, and O-rings 74 are attached to the seal grooves 72a and 72b, respectively. A thick portion 76 is formed on the back surface side of the connecting member 50, that is, on the side surfaces 51a and 51b side of the end plates 18a and 18b. The thick portion 76 contacts the side surfaces 51a and 51b of the end plates 18a and 18b. Touch. The thick part 76 is formed by thinning the fuel cell 12 side of the connecting member 50. This is to prevent interference with the fuel cell 12 and reduce the weight of the connecting member 50.

  As shown in FIG. 1, the end plate 18a includes an oxidant gas inlet communication hole 26a, a fuel gas inlet communication hole 28a, a cooling medium inlet communication hole 30a, an oxidant gas outlet communication hole 26b, a fuel gas outlet communication hole 28b, and A manifold (not shown) that communicates with the cooling medium outlet communication hole 30b and extends to the outside is provided, while the end plate 18b is configured in a closed plate shape.

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

  First, as shown in FIG. 2, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet communication hole 26a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 28a. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the cooling medium inlet communication hole 30a.

  Therefore, the oxidant gas is introduced into the oxidant gas flow path 32 of the first separator 22 from the oxidant gas inlet communication hole 26a. The oxidant gas is supplied to the cathode side electrode 44 constituting the electrolyte membrane / electrode structure 20 while moving in the arrow B direction.

  On the other hand, the fuel gas is introduced into the fuel gas flow path 34 of the second separator 24 from the fuel gas inlet communication hole 28a. The fuel gas is supplied to the anode side electrode 46 constituting the electrolyte membrane / electrode structure 20 while moving in the arrow B direction.

  Therefore, in the electrolyte membrane / electrode structure 20, the oxidant gas supplied to the cathode side electrode 44 and the fuel gas supplied to the anode side electrode 46 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 44 is discharged in the direction of arrow A along the oxidant gas outlet communication hole 26b. On the other hand, the fuel gas consumed by being supplied to the anode electrode 46 is discharged in the direction of arrow A along the fuel gas outlet communication hole 28b.

  The cooling medium supplied to the cooling medium inlet communication hole 30a is introduced into the cooling medium flow path 36 between the first and second separators 22 and 24 and then flows in the direction of arrow C. After cooling the electrolyte membrane / electrode structure 20, the cooling medium is discharged from the cooling medium outlet communication hole 30b.

  In this case, in the first embodiment, the fuel cell stack 10 includes a plurality of connecting members 50 spanned between a pair of end plates 18a and 18b, side surfaces 51a and 51b of the end plates 18a and 18b, and the connecting members. 50, the holding mechanism 52 for applying tension in the tightening direction, and the fixing mechanism for fixing the side surfaces 51a, 51b of the end plates 18a, 18b and the both ends of the connecting member 50 to each other. 54.

  Therefore, tension is applied to the connecting member 50 and the end plates 18a and 18b in the tightening direction via the holding mechanism 52, and the connecting member 50 and the end plates 18a and 18b are connected via the fixing mechanism 54. The fastening force is maintained. Therefore, a desired tightening force can be reliably applied with a simple configuration, and the distance between the end plates 18a and 18b can be kept constant by the connecting member 50 and the holding mechanism 52.

  Furthermore, when an external load is applied to the fuel cell stack 10, it is possible to prevent the coupling member 50 from peeling off under the action of the fixing mechanism 54.

  In addition, the connecting member 50 can protect the fuel cell 12 by receiving an external impact and can prevent the fuel cell 12 from being deformed (bent).

  Furthermore, the holding mechanism 52 includes a first hole 56a provided in the side surfaces 51a and 51b of the end plates 18a and 18b, a second hole 56b provided at both ends of the connecting member 50, and the first and second holes. And a pin member 58 that is integrally inserted into the portions 56a and 56b. Thereby, there is an advantage that the configuration of the holding mechanism 52 is simplified and economical.

  In addition, reinforcing rings 60a and 60b made of an iron-based material are press-fitted into the first and second holes 56a and 56b. For this reason, the first and second holes 56a and 56b, which hold the fastening load by inserting the pin member 58, can effectively prevent deformation due to the fastening load.

  Furthermore, O-rings 74 are disposed in the seal grooves 72 a and 72 b formed at both ends of the connecting member 50 as a seal member for sealing the pin member 58. Therefore, in particular, the pin member 58 made of an iron-based material is isolated from the water environment in terms of strength, so that it is possible to prevent the pin member 58 from being electrically contacted.

  FIG. 5 is a perspective explanatory view of a fuel cell stack 80 according to the second embodiment of the present invention.

  The same components as those of the fuel cell stack 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The fuel cell stack 80 is provided on the connecting member 82 spanned between the pair of end plates 18a, 18b, the side surfaces 51a, 51b of the end plates 18a, 18b, and the connecting member 82. A holding mechanism 84 for applying, and a fixing mechanism 86 for fixing the side surfaces 51a and 51b of the end plates 18a and 18b and the connecting member 82 to each other are provided.

  Similar to the connecting member 50 of the first embodiment, two connecting members 82 are disposed on the long side and one on the short side, respectively, and the oxidant gas inlet communication hole 26a, The fuel gas inlet communication hole 28a, the cooling medium inlet communication hole 30a, the oxidant gas outlet communication hole 26b, the fuel gas outlet communication hole 28b, and the cooling medium outlet communication hole 30b are provided at positions offset from each other.

  As shown in FIG. 6, the holding mechanism 84 is provided at both ends of the projections 88 provided on the side surfaces 51 a and 51 b of the end plates 18 a and 18 b and the connecting member 82, and protrudes outward in the width direction of the connecting member 82. And a protrusion 90 that engages with the protrusion 88.

  The protrusion 88 protrudes outward from the side surfaces 51a and 51b of the end plates 18a and 18b over a predetermined length and is provided with a locking portion 88a that bulges at both ends. The protrusion 90 is disposed outward in the stacking direction across the protrusion 88, and a spacer member 92 for adjusting the dimension in the stacking direction is provided between the protrusion 88 and the protrusion 90. Intervened.

  The protruding portion 90 is provided with a hook portion 94 that abuts against the protruding portion 88 by forming a stepped shape that protrudes toward the side surfaces 51a and 51b of the end plates 18a and 18b.

  The fixing mechanism 86 includes a screw hole 96 formed in the side surfaces 51a and 51b of the end plates 18a and 18b, a hole 98 formed in the protrusion 90 of the connecting member 82, and the screw 98 inserted into the hole 98. And a screw 100 to be screwed into the hole 96. The protrusion 90 is provided with a recess 102 for placing the screw 100.

  In the second embodiment configured as described above, the protrusions 90 provided at both ends in the longitudinal direction of the connecting member 82 are attached across the protrusions 88 provided in the end plates 18a and 18b. Yes. Accordingly, the protrusion 88 and the protrusion 90 are pressure-bonded to each other, and tension is applied to the fuel cell stack 80 in the tightening direction.

  At that time, the fastening force between the connecting member 82 and the end plates 18 a and 18 b is maintained via the fixing mechanism 86. Thereby, in 2nd Embodiment, the effect similar to said 1st Embodiment is acquired, and adjustment of distance between the end plates 18a and 18b is attained by the connection member 82 and the holding mechanism 84. FIG.

DESCRIPTION OF SYMBOLS 10, 80 ... Fuel cell stack 12 ... Fuel cell 18a, 18b ... End plate 20 ... Electrolyte membrane electrode assembly 22, 24 ... Separator 26a ... Oxidant gas inlet communication hole 26b ... Oxidant gas outlet communication hole 28a ... Fuel gas Inlet communication hole 28b ... Fuel gas outlet communication hole 30a ... Cooling medium inlet communication hole 30b ... Cooling medium outlet communication hole 32 ... Oxidant gas flow path 34 ... Fuel gas flow path 36 ... Cooling medium flow path 42 ... Solid polymer electrolyte membrane 44 ... Cathode side electrode 46 ... Anode side electrode 50, 82 ... Connection member 52, 84 ... Holding mechanism 54, 86 ... Fixing mechanism 56a, 56b, 66, 70, 98 ... Hole 58 ... Pin member 60a, 60b ... Reinforcement ring 62, 96 ... Screw hole 64, 100 ... Screw 74 ... O-ring 88 ... Projection portion 88a ... Locking portion 90 ... Projection portion 92 ... Spacer member

Claims (7)

A fuel cell in which an electrolyte membrane / electrode structure provided with a pair of electrodes on both sides of the electrolyte membrane and a separator are stacked, and a plurality of the fuel cells are stacked, and end plates are provided at both ends in the stacking direction. A fuel cell stack,
A connecting member spanned between the pair of end plates;
A holding mechanism that is provided on a side surface of the end plate and the connecting member and applies tension in a tightening direction;
A fixing mechanism for fixing the side surface of the end plate and the connecting member to each other;
Equipped with a,
The holding mechanism includes a protrusion provided on a side surface of the end plate;
Protruding portions provided on the connecting member, projecting outward in the width direction of the connecting member, straddling the projecting portions outward in the stacking direction,
Fuel cell stack according to claim Rukoto equipped with. 2. The fuel cell stack according to claim 1, wherein the protruding portion protrudes outward by a predetermined length from a side surface of the end plate, and a locking portion that bulges outward is provided at both ends of the protruding portion. And fuel cell stack. The fuel cell stack according to claim 1 or 2,
The fixing mechanism includes a screw hole formed in a side surface of the end plate, a hole formed in a protruding portion of the connecting member, and a screw inserted into the hole and screwed into the screw hole. A fuel cell stack. 4. The fuel cell stack according to claim 1, wherein the protruding portion is provided with a hooking portion protruding toward a side surface of the end plate, and the hooking portion is in contact with the protruding portion. Fuel cell stack. 5. The fuel cell stack according to claim 3, wherein a concave portion for arranging the screw is formed in the protruding portion. 6. 6. The fuel cell stack according to claim 1 , wherein a spacer member for adjusting a dimension in the stacking direction is interposed between the protrusion and the protrusion. Fuel cell stack. The fuel cell stack according to any one of claims 1 to 6, wherein the fuel cell is provided with a fluid communication hole that communicates in the stacking direction and allows a reaction gas and a cooling medium to flow.
A fuel cell stack, wherein a connecting portion between the connecting member and a side surface of the end plate is provided at a position offset from the fluid communication hole.

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