JP2013157095A - Fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize peeling of a seal member formed integrally with a separator with a simple configuration.SOLUTION: In a fuel cell 10, an electrolyte membrane/electrode structure 16 is held by an anode side separator 18 and a cathode side separator 20. In the anode side separator 18, a first seal member 44 is molded on both sides of a metal plate 22 integrally therewith, at the outer peripheral end thereof. A film member 48a is bonded to the boundary of an end 44ae of the first seal member 44 and a plate surface 22a of the metal plate 22, from the end 44ae of the first seal member 44 across the plate surface 22a.

Description

  The present invention relates to 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 laminated.

  For example, a solid polymer fuel cell employs a solid polymer electrolyte membrane made of a polymer ion exchange membrane. In this fuel cell, an electrolyte membrane / electrode structure (MEA) configured by arranging an anode electrode and a cathode electrode made of an electrode catalyst and porous carbon on both sides of a solid polymer electrolyte membrane is provided with a separator (bipolar plate). ) To hold the power generation cell. A fuel cell in which a plurality of power generation cells are stacked is used as, for example, an in-vehicle fuel cell stack.

  In a fuel cell, a flow path for flowing fuel gas (hereinafter also referred to as a reaction gas) is formed on the separator surface facing the anode electrode, while an oxidant gas (on the separator surface facing the cathode electrode) is formed. Hereinafter, a flow path for flowing a reaction gas) is also provided. Further, a flow path for flowing a cooling medium between the separators is formed for each power generation cell or for each predetermined number of power generation cells.

  At that time, it is necessary to securely seal between the flow paths so that the fuel gas, the oxidant gas and the cooling medium are not mixed with each other. It is necessary to prevent. For this reason, for example, a separator in which seal members are integrally formed on both surfaces of the outer peripheral edge of a metal plate or carbon plate is employed.

  As this type of separator, for example, a fuel cell separator disclosed in Patent Document 1 is known. As shown in FIG. 5, the separator includes a separator body 1, and a gasket 3 is integrally formed on the separator body 1 through a through hole 2 provided in the separator body 1.

  The gasket 3 includes a pedestal portion 4a that is in contact with the one surface 1a of the separator body 1, a lip-shaped seal portion 5a that is supported by the pedestal portion 4a, and a lip portion that is in contact with the other surface 1b of the separator body 1. 4b, a lip-shaped seal portion 5b having a substantially triangular cross section supported by the pedestal portion 4b, and a connecting portion 6 disposed in each through portion 2 and connecting the pedestal portions 4a and 4b are integrally provided. It has been.

JP 2002-50369 A

  By the way, in said patent document 1, the base parts 4a and 4b are only in contact with the one surface 1a and the other surface 1b of the separator main body 1. FIG. For this reason, there is a problem that the pedestals 4a and 4b are easily separated from the one surface 1a and the other surface 1b of the separator body 1 while the separator is incorporated in the fuel cell and used for power generation. In addition, there is a problem that the configuration becomes complicated and the manufacturing cost increases.

  An object of the present invention is to solve this type of problem, and to provide a fuel cell that can suppress the peeling of a sealing member integrally formed with a separator as much as possible with a simple configuration. To do.

  The present invention relates to 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 laminated. In this fuel cell, the separator is integrally molded with both surfaces of the outer peripheral edge portion, and the boundary portion between the end portion of the seal member and the plate surface of the separator is formed from the end portion of the seal member. A film member is bonded across the plate surface of the separator.

  Further, in this fuel cell, it is preferable that the boundary portion is in close contact with the boundary portion on the plate surface of the separator in the order of the end of the seal member and the film member.

  Further, in this fuel cell, the film member is preferably provided in a frame shape over the entire circumference of the seal member.

  In the present invention, the film member is bonded from the end of the seal member to the plate surface of the separator. For this reason, the end of the seal member is reliably prevented from being peeled off from the plate surface, and it is possible to suppress the peel of the seal member integrally formed on the separator as much as possible with a simple configuration.

1 is a partially exploded schematic perspective view of a power generation cell constituting a fuel cell according to a first embodiment of the present invention. It is a partial cross section explanatory view of the fuel cell. It is front explanatory drawing of the anode side separator which comprises the said electric power generation cell. It is a partial cross section explanatory view of the fuel cell concerning a 2nd embodiment of the present invention. 6 is an explanatory diagram of a fuel cell separator disclosed in Patent Document 1. FIG.

  As shown in FIGS. 1 and 2, in the fuel cell 10 according to the first embodiment of the present invention, a plurality of power generation cells 12 are stacked in the horizontal direction (arrow A direction) or the vertical direction (arrow C direction). .

  The power generation cell 12 includes an electrolyte membrane / electrode structure (MEA) 16, and an anode side separator 18 and a cathode side separator 20 that sandwich the electrolyte membrane / electrode structure 16. The anode-side separator 18 and the cathode-side separator 20 have a concavo-convex shape by pressing a thin metal plate 22 and a metal plate 24 into a wave shape, a dimple shape, or the like, respectively (see FIG. 2). Instead of the metal plate 22 and the metal plate 24, a carbon plate or the like may be used.

  An oxidant gas supply for supplying an oxidant gas, for example, an oxygen-containing gas, to one end edge of the power generation cell 12 in the long side direction (the arrow B direction in FIG. 1) in communication with the arrow A direction. A communication hole 26a, a cooling medium supply communication hole 28a for supplying a cooling medium, and a fuel gas discharge communication hole 30b for discharging a fuel gas, for example, a hydrogen-containing gas, are provided.

  The other end edge in the long side direction of the power generation cell 12 communicates with each other in the direction of the arrow A, the fuel gas supply communication hole 30a for supplying fuel gas, and the cooling medium discharge communication hole for discharging the cooling medium. 28b, and an oxidant gas discharge communication hole 26b for discharging the oxidant gas.

  The electrolyte membrane / electrode structure 16 includes, for example, a solid polymer electrolyte membrane 32 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode electrode 34 and a cathode electrode 36 sandwiching the solid polymer electrolyte membrane 32. Prepare.

  The anode electrode 34 and the cathode electrode 36 include a gas diffusion layer made of carbon paper or the like, and an electrode catalyst layer in which porous carbon particles having a platinum alloy supported on the surface are uniformly applied to the surface of the gas diffusion layer. Have. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 32.

  As shown in FIG. 3, a fuel gas flow path 38 that connects the fuel gas supply communication hole 30a and the fuel gas discharge communication hole 30b is formed on the surface 18a of the anode separator 18 facing the electrolyte membrane / electrode structure 16. Is done. The fuel gas channel 38 is constituted by, for example, a plurality of grooves extending in the arrow B direction. As shown in FIG. 1, a cooling medium flow path 40 that connects the cooling medium supply communication hole 28 a and the cooling medium discharge communication hole 28 b is formed on the surface 18 b of the anode-side separator 18. The cooling medium flow path 40 is constituted by a plurality of grooves extending in the arrow B direction.

  On the surface 20a of the cathode-side separator 20 facing the electrolyte membrane / electrode structure 16, for example, an oxidant gas flow path 42 composed of a plurality of grooves extending in the direction of arrow B is provided. The oxidant gas flow path 42 communicates with the oxidant gas supply communication hole 26a and the oxidant gas discharge communication hole 26b. A cooling medium flow path 40 is integrally formed on the surface 20 b of the cathode side separator 20 so as to overlap the surface 18 b of the anode side separator 18.

  A first seal member 44 is integrally formed on the surfaces 18 a and 18 b of the anode separator 18 around the outer peripheral end of the metal plate 22. A second seal member 46 is integrally formed on the surfaces 20 a and 20 b of the cathode separator 20 around the outer peripheral end of the cathode separator 20.

  The first seal member 44 and the second seal member 46 are, for example, EPDM, NBR, fluorine rubber, silicon rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene, or acrylic rubber, or a cushioning material. Or use packing material.

  As shown in FIGS. 2 and 3, the first seal member 44 is formed with a uniform thickness on the surface 18 a (plate surface 22 a), and includes a flat seal portion 44 a surrounding the fuel gas flow path 38. And a convex seal portion 44b that protrudes from the flat seal portion 44a and communicates the fuel gas passage 38 with the fuel gas supply communication hole 30a and the fuel gas discharge communication hole 30b.

  Between the fuel gas supply communication hole 30 a and the fuel gas flow path 38, a plurality of convex-shaped inlet bridge portions 45 a are provided, and between the fuel gas discharge communication hole 30 b and the fuel gas flow path 38. Is provided with a plurality of convex-shaped outlet bridge portions 45b. The inlet bridge portion 45a and the outlet bridge portion 45b are preferably configured integrally with the first seal member 44.

  As shown in FIG. 1, the first seal member 44 is formed with a uniform thickness on the surface 18 b (plate surface 22 b), and includes a flat seal portion 44 c that surrounds the cooling medium flow path 40, and the flat surface. It has a convex seal portion 44d that protrudes from the seal portion 44c and communicates the cooling medium flow path 40 with the cooling medium supply communication hole 28a and the cooling medium discharge communication hole 28b.

  Between the cooling medium supply communication hole 28 a and the cooling medium flow path 40, a plurality of convex-shaped inlet bridge portions 45 c are provided, and between the cooling medium discharge communication hole 28 b and the cooling medium flow path 40. Are provided with a plurality of convex-shaped outlet bridge portions 45d. The inlet bridge portion 45 c and the outlet bridge portion 45 d are preferably configured integrally with the first seal member 44.

  As shown in FIGS. 1 and 2, the second seal member 46 is formed with a uniform thickness on the surface 20 a (plate surface 24 a) and surrounds the oxidant gas flow path 42. And a convex seal portion 46b that protrudes from the flat seal portion 46a and communicates the oxidant gas flow path 42 with the oxidant gas supply communication hole 26a and the oxidant gas discharge communication hole 26b.

  Between the oxidant gas supply communication hole 26a and the oxidant gas flow path 42, a plurality of convex-shaped inlet bridge portions 47a are provided, while the oxidant gas discharge communication hole 26b and the oxidant gas flow path are provided. A plurality of convex-shaped exit bridge portions 47b are provided between the two. The inlet bridge portion 47 a and the outlet bridge portion 47 b are preferably configured integrally with the second seal member 46.

  As shown in FIG. 2, the second seal member 46 is formed with a uniform thickness on the surface 20 b (plate surface 24 b), and surrounds the cooling medium flow path 40 with the flat seal portion 46 c. A convex seal portion 46d that protrudes from the seal portion 46c and communicates the cooling medium flow path 40 with the cooling medium supply communication hole 28a and the cooling medium discharge communication hole 28b.

  Between the cooling medium supply communication hole 28a and the cooling medium flow path 40, and between the cooling medium discharge communication hole 28b and the cooling medium flow path 40, a plurality of convex-shaped inlet bridge portions and An exit bridge is provided.

  As shown in FIGS. 2 and 3, on the plate surface 22a of the metal plate 22 on the fuel gas flow path 38 side, the end of the first seal member 44, that is, the end 44ae of the flat seal 44a and the metal plate are provided. The film member 48 a is bonded to the boundary portion between the plate surface 22 a and the plate surface 22 a from the end 44 ae of the flat seal portion 44 a to the plate surface 22 a of the metal plate 22.

  At the boundary portion, the end portion 44ae of the flat seal portion 44a and the film member 48a are in close contact with each other on the plate surface 22a of the metal plate 22, so that no gap is provided between them. In a state where the fuel cell 10 is configured by laminating a plurality of power generation cells 12 and applying a tightening load, the convex seal portion 44b is compressed and deformed, so that a film member is formed on the inner wall surface of the convex seal portion 44b. The edge part of 48a closely_contact | adheres (refer FIG. 2). For example, the convex seal portion 44d is compressed and deformed from a state where the tightening force is not applied (see the dashed line in FIG. 2) to a state where the tightening force is applied (see the solid line in FIG. 2).

  The film member 48a is made of, for example, a resin film such as PEN (polyethylene naphthalate) or PPS (polyphenylene sulfide). The film member 48 a has a frame shape and is provided over the entire circumference of the flat seal portion 44 a constituting the first seal member 44.

  As shown in FIGS. 1 and 2, on the plate surface 22b of the metal plate 22 on the cooling medium flow path 40 side, the end portion of the first seal member 44, that is, the end portion 44ce of the flat seal portion 44c and the metal plate are provided. The film member 48b is bonded to the boundary portion of the flat seal portion 44c from the end portion 44ce of the flat seal portion 44c to the plate surface 22b of the metal plate 22.

  The film member 48b is configured the same as the film member 48a. The film member 48 b has a frame shape and is provided over the entire circumference of the flat seal portion 44 c constituting the first seal member 44.

  At the boundary portion, the end portion 44ce of the flat seal portion 44c and the film member 48b are brought into close contact with each other on the plate surface 22b of the metal plate 22, so that no gap is provided between them. In the state in which the fuel cell 10 is configured, the end of the film member 48b comes into close contact with the inner wall surface of the convex seal portion 44d by compressing and deforming the convex seal portion 44d (see FIG. 2).

  As shown in FIGS. 1 and 2, the end surface of the second seal member 46, that is, the end portion 46 ae of the flat seal portion 46 a and the metal plate 24 a on the oxidant gas flow path 42 side of the metal plate 24. The film member 50a is bonded to the boundary portion between the plate 24 and the plate surface 24a from the end 46ae of the flat seal portion 46a to the plate surface 24a of the metal plate 24.

  At the boundary portion, the end portion 46ae of the flat seal portion 46a and the film member 50a are in close contact with each other on the plate surface 24a of the metal plate 24, so that no gap is provided between them. In a state where the fuel cell 10 is configured by laminating a plurality of power generation cells 12 and applying a tightening load, the convex seal portion 46b is compressed and deformed, whereby a film member is formed on the inner wall surface of the convex seal portion 46b. The end part of 50a closely_contact | adheres (refer FIG. 2).

  The film member 50a is configured the same as the film member 48a. The film member 48 a has a frame shape and is provided over the entire circumference of the flat seal portion 46 a constituting the second seal member 46.

  As shown in FIG. 2, the end surface of the second seal member 46, that is, the end portion 46 ce of the flat seal portion 46 c and the metal plate 24 are disposed on the plate surface 24 b of the metal plate 24 on the cooling medium flow path 40 side. The film member 50b is bonded to the boundary portion with the plate surface 24b from the end portion 46ce of the flat seal portion 46c to the plate surface 24b of the metal plate 24.

  The film member 50b is configured the same as the film member 48a. The film member 50 b has a frame shape and is provided over the entire circumference of the flat seal portion 46 c constituting the second seal member 46.

  At the boundary portion, the end portion 46ce of the flat seal portion 46c and the film member 50b are in close contact with each other on the plate surface 24b of the metal plate 24, so that no gap is provided therebetween. In the state where the fuel cell 10 is configured, the end of the film member 50b comes into close contact with the inner wall surface of the convex seal portion 46d by compressing and deforming the convex seal portion 46d (see FIG. 2).

  An operation for manufacturing the anode separator 18 in the fuel cell 10 configured as described above will be described below. In addition, since the cathode side separator 20 is manufactured similarly to the anode side separator 18, the detailed description is abbreviate | omitted.

  First, the metal plate 22 constituting the anode-side separator 18 is placed in an injection molding machine (not shown), and the first seal member 44 is injection-molded on the metal plate 22.

  Here, when the first seal member 44 is injection-molded on the metal plate 22, the oxidant gas supply communication hole 26a, the oxidant gas discharge communication hole 26b, the cooling medium supply communication hole 28a, the cooling medium discharge communication hole 28b, the fuel The gas supply communication hole 30a and the fuel gas discharge communication hole 30b are closed. Therefore, corresponding to the oxidant gas supply communication hole 26a, the oxidant gas discharge communication hole 26b, the cooling medium supply communication hole 28a, the cooling medium discharge communication hole 28b, the fuel gas supply communication hole 30a, and the fuel gas discharge communication hole 30b. Trimming is performed.

  On the other hand, film members 48a and 48b formed in a frame shape are prepared, and an adhesive is applied in advance to each bonding surface. The film members 48a and 48b are attached to predetermined portions with respect to the metal plate 22 at the time of the trimming process.

  Specifically, the film member 48a is formed on the plate surface 22a of the metal plate 22 from the end portion 44ae to the plate surface 22a corresponding to the boundary portion between the end portion 44ae of the flat seal portion 44a and the plate surface 22a. It is bonded over. The film member 48b is bonded to the plate surface 22b of the metal plate 22 from the end portion 44ce to the plate surface 22b corresponding to the boundary portion between the end portion 44ce of the flat seal portion 44c and the plate surface 22b. The Thereby, the anode side separator 18 is manufactured.

  Next, the operation of the fuel cell 10 constituted by the anode side separator 18, the cathode side separator 20, and the electrolyte membrane / electrode structure 16 manufactured as described above will be described below.

  As shown in FIG. 1, in the fuel cell 10, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas supply communication hole 26a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas supply communication hole 30a. Supplied. Further, a coolant such as pure water or ethylene glycol is supplied to the coolant supply passage 28a. For this reason, in each power generation cell 12, the oxidant gas, the fuel gas, and the cooling medium are respectively supplied in the direction of arrow A.

  The oxidant gas is introduced into the oxidant gas flow path 42 of the cathode separator 20 from the oxidant gas supply communication hole 26 a and moves along the cathode electrode 36 of the electrolyte membrane / electrode structure 16. On the other hand, the fuel gas is introduced into the fuel gas flow path 38 of the anode separator 18 from the fuel gas supply communication hole 30 a and moves along the anode electrode 34 of the electrolyte membrane / electrode structure 16.

  Accordingly, in each electrolyte membrane / electrode structure 16, the oxidant gas supplied to the cathode electrode 36 and the fuel gas supplied to the anode electrode 34 are consumed by an electrochemical reaction in the electrode catalyst layer, thereby generating power. Done.

  Next, the oxidant gas consumed by being supplied to the cathode electrode 36 is discharged to the oxidant gas discharge communication hole 26b and flows in the direction of arrow A. Similarly, the fuel gas consumed by being supplied to the anode electrode 34 is discharged to the fuel gas discharge communication hole 30b and flows in the direction of arrow A.

  Further, the cooling medium flows into the cooling medium flow path 40 between the anode-side separator 18 and the cathode-side separator 20 through the cooling medium supply communication hole 28a, and then flows along the arrow B direction. The cooling medium cools the electrolyte membrane / electrode structure 16, and then moves through the cooling medium discharge communication hole 28 b and is discharged from the fuel cell 10.

  In this case, in the first embodiment, as shown in FIGS. 2 and 3, the frame-shaped film member 48 a is disposed on the plate surface 22 a of the metal plate 22 and the end of the flat seal portion 44 a of the first seal member 44. Corresponding to the boundary part between 44ae and the plate surface 22a, the plate 44a is bonded from the end 44ae to the plate surface 22a.

  For this reason, the end portion 44ae of the first seal member 44 is reliably prevented from peeling from the plate surface 22a. Therefore, it is possible to obtain an effect that it is possible to suppress the peeling of the first seal member 44 integrally formed with the anode side separator 18 as much as possible with a simple configuration.

  Furthermore, the end portion 44ae of the flat seal portion 44a and the film member 48a are brought into close contact with each other on the plate surface 22a of the metal plate 22, so that no gap is provided between them. Thereby, peeling of the 1st seal member 44 can be suppressed as much as possible.

  Moreover, in the state in which the fuel cell 10 is configured, the end of the film member 48a is in close contact with the inner wall surface of the convex seal portion 44b by compressing and deforming the convex seal portion 44b (see FIG. 2). ). For this reason, peeling of the first seal member 44 can be more reliably suppressed.

  In addition, in the film members 48b, 50a, and 50b, the effect similar to said film member 48a is acquired.

  FIG. 4 is a partial cross-sectional explanatory view of a fuel cell 60 according to the second embodiment of the present invention. The same components as those of the fuel cell 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The fuel cell 60 is configured by stacking a plurality of power generation cells 62. The power generation cell 62 includes an electrolyte membrane / electrode structure 16, and an anode separator 64 and a cathode separator 66 that sandwich the electrolyte membrane / electrode structure 16.

  The anode-side separator 64 is integrally formed with the first seal member 44, and the tip end of the end 44 ae of the first seal member 44 is tapered toward the plate surface 22 a of the metal plate 22. 44 aet is provided. On the plate surface 22a of the metal plate 22, the end portion 44ae including the tapered tip end portion 44aet of the flat seal portion 44a and the film member 48a are in close contact with each other, so that a gap is provided between them. There is no. The same applies hereinafter.

  At the tip of the end 44ce of the first seal member 44, a tapered tip 44cet that is inclined toward the plate surface 22b of the metal plate 22 is provided. A tapered tip end 46 aet that is inclined toward the plate surface 24 a of the metal plate 24 is provided at the tip of the end 46 ae of the second seal member 46. A tapered tip end 46 cet that is inclined toward the plate surface 24 b of the metal plate 24 is provided at the tip of the end 46 ce of the second seal member 46.

  In the second embodiment configured as described above, for example, the tip end of the end portion 44 ae of the first seal member 44 is provided with a tapered tip end portion 44 aet that is inclined toward the plate surface 22 a of the metal plate 22. Yes. For this reason, the advantage that the attaching operation of the film member 48a can be performed more easily and reliably is obtained, and the same effect as the first embodiment is obtained.

DESCRIPTION OF SYMBOLS 10, 60 ... Fuel cell 12, 62 ... Power generation cell 16 ... Electrolyte membrane and electrode structure 18, 64 ... Anode side separator 20, 66 ... Cathode side separator 22, 24 ... Metal plate 26a ... Oxidant gas supply communication hole 26b ... Oxidant gas discharge communication hole 28a ... cooling medium supply communication hole 28b ... cooling medium discharge communication hole 30a ... fuel gas supply communication hole 30b ... fuel gas discharge communication hole 32 ... solid polymer electrolyte membrane 34 ... anode electrode 36 ... cathode electrode 38 ... Fuel gas flow path 40 ... Cooling medium flow path 42 ... Oxidant gas flow paths 44, 46 ... Seal members 44a, 44c, 46a, 46c ... Flat seal portions 44b, 44d, 46b, 46d ... Convex seal portions 48a, 48b , 50a, 50b ... film members

Claims (3)

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 laminated,
The separator is integrally formed with seal members on both sides of the outer peripheral edge,
A fuel cell, wherein a film member is adhered to a boundary portion between an end portion of the seal member and a plate surface of the separator from the end portion of the seal member to the plate surface of the separator.   2. The fuel cell according to claim 1, wherein the boundary portion is in close contact with the end portion of the seal member and the film member in this order on the plate surface of the separator.   3. The fuel cell according to claim 1 or 2, wherein the film member is provided in a frame shape over the entire circumference of the seal member.

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