JP2016035844A - Fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell in which a separator can be prevented from being deformed as much as possible with a simple constitution, the separator having a double-sealed structure including an inner seal member and an outer seal member.SOLUTION: A fuel cell 10 holds an electrolyte membrane-electrode structure 12 between a first separator 14 and a second separator 16. A first seal member 42 is integrally molded on a surface 14b of the first separator 14. The first seal member 42 is located between a second inner seal member 42c and an outer seal member 42d and integrally molds an intermediate supporting member 42e. The intermediate supporting member 42e has a height dimension set lower than those of the second inner seal member 42c and the outer seal member 42d.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fuel cell having a double seal structure including an electrolyte membrane / electrode structure in which electrodes are provided on both sides of an electrolyte membrane, and a pair of separators that sandwich the electrolyte membrane / electrode structure.

  In general, a polymer electrolyte fuel cell employs a polymer electrolyte membrane made of a polymer ion exchange membrane. This fuel cell has an electrolyte membrane / electrode structure in which an anode electrode and a cathode electrode each comprising a catalyst layer (electrode catalyst layer) and a gas diffusion layer (porous carbon) are disposed on both sides of a solid polymer electrolyte membrane, respectively. (MEA). The electrolyte membrane / electrode structure constitutes a fuel cell by being sandwiched between a pair of separators (bipolar plates). A predetermined number of the fuel cells are stacked and mounted on a fuel cell electric vehicle as an in-vehicle fuel cell stack, for example.

  In the fuel cell, in order to prevent gas leakage and the like, it is necessary to keep the fuel gas and the oxidant gas hermetically, and to keep the cooling medium liquid-tight in order to maintain the cooling function. For this reason, various seal members are employed. At that time, for example, a thin metal separator may be used as the separator. Therefore, when a tightening load is applied to the metal separator, there is a problem that the metal separator is easily deformed by a seal load.

  Thus, for example, a fuel cell disclosed in Patent Document 1 is known. In this fuel cell, the laminated body is integrally provided with a seal member for preventing leakage of the reaction gas, and the seal member is in contact with the opposing separator, respectively, and the first seal portion and the second seal portion. It has. The first seal portion and the second seal portion are formed at positions separated by a predetermined distance when viewed from the stacking direction.

  For this reason, when a fastening load is applied in the stacking direction of the fuel cell stack, the fastening load applied to the first seal portion is applied to the second seal portion, and the fastening load applied to the second seal portion is applied to the first seal portion. In addition, it is possible not to participate directly. Therefore, when a fastening load is applied in the stacking direction of the fuel cell stack, it is possible to suppress the first seal portion and the second seal portion from being obliquely deformed with respect to the load direction. Yes.

JP 2007-207707 A

  By the way, in the separator, the supply pressure of the reaction gas supplied to the reaction gas flow path provided on one surface side and the cooling medium flow path (or other reaction gas flow path) provided on the other surface side are supplied. The supply pressure of the cooling medium (or other reaction gas) may be different. For this reason, in Patent Document 1 described above, if the first seal portion and the second seal portion are formed at positions relatively far apart when viewed from the stacking direction, the pressure difference between the supply pressures on both sides of the separator This causes a problem that the separator is deformed.

  The present invention solves this type of problem, and with a simple configuration, it is possible to suppress as much as possible the deformation of the separator having a double seal structure in which the inner seal member and the outer seal member are provided. An object of the present invention is to provide a simple fuel cell.

  The fuel cell according to the present invention has an electrolyte membrane / electrode structure in which electrodes are provided on both sides of the electrolyte membrane, and the electrolyte membrane / electrode structure is sandwiched between a pair of separators. The fuel cell has a double seal structure having an inner seal member that is provided around the power generation region and an outer seal member that is provided around the outside of the inner seal member when viewed from the clamping direction (stacking direction). Is adopted.

  An intermediate support member that is integrally formed with at least one of the inner seal member or the outer seal member and that is lower in height than the one is provided between the inner seal member and the outer seal member. Yes.

  Moreover, in this fuel cell, it is preferable that a cooling medium flow path for allowing the cooling medium to flow along the separator surface is formed between adjacent separators. At this time, the intermediate support member is preferably formed between an inner seal member and an outer seal member provided on the cooling medium flow path side.

  Furthermore, in this fuel cell, it is preferable that a reaction gas flow path for allowing a reaction gas to flow along the separator surface is formed on the surface facing the electrolyte membrane / electrode structure between the separators. At this time, the intermediate support member is preferably formed between an inner seal member and an outer seal member provided on the reaction gas flow path side.

  According to the present invention, in the separator having the double seal structure, the intermediate support member is provided between the inner seal member and the outer seal member. For this reason, an intermediate support member is provided corresponding to a portion where the distance between the inner seal member and the outer seal member is set to be relatively large, that is, a portion where the separator is likely to be deformed due to the differential pressure on both sides of the separator. Can do.

  Thereby, it becomes possible to suppress as much as possible the deformation of the separator having the double seal structure in which the inner seal member and the outer seal member are provided with a simple configuration.

It is a principal part disassembled perspective explanatory view of the fuel cell concerning the embodiment of the present invention. FIG. 2 is a sectional view of the fuel cell taken along line II-II in FIG. 1. It is explanatory drawing of one surface of the 2nd separator which comprises the said fuel cell. It is front explanatory drawing of the 1st separator which comprises the said fuel cell. It is explanatory drawing of the other surface of the said 2nd separator. It is the VI-VI sectional view taken on the line of the said 1st separator in FIG. It is the VII-VII sectional view taken on the line of the said 2nd separator in FIG.

  As shown in FIG. 1 and FIG. 2, the fuel cell 10 according to the embodiment of the present invention is stacked in the standing position and in the direction of arrow A (for example, the horizontal direction), for example, an in-vehicle fuel cell. Used as a stack.

  The fuel cell 10 includes an electrolyte membrane / electrode structure 12, and a first separator 14 and a second separator 16 that sandwich the electrolyte membrane / electrode structure 12. The first separator 14 and the second separator 16 are made of, for example, a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, or the like, but may be made of a carbon member or the like.

  As shown in FIG. 2, the electrolyte membrane / electrode structure 12 includes an MEA component 12a. The MEA component 12 a includes, for example, a solid polymer electrolyte membrane 18 in which a perfluorosulfonic acid thin film is impregnated with water, and a cathode electrode 20 and an anode electrode 22 that sandwich the solid polymer electrolyte membrane 18. The solid polymer electrolyte membrane 18 uses an HC (hydrocarbon) electrolyte in addition to a fluorine electrolyte.

  The anode electrode 22 has a smaller planar dimension than the cathode electrode 20. The cathode electrode 20 may have a smaller planar dimension than the anode electrode 22, and the cathode electrode 20 and the anode electrode 22 may have the same planar dimension.

  The cathode electrode 20 includes a first electrode catalyst layer 20a disposed on one surface 18a of the solid polymer electrolyte membrane 18, and a first gas diffusion layer 20b stacked on the first electrode catalyst layer 20a. The planar dimension of the first electrode catalyst layer 20a and the planar dimension of the first gas diffusion layer 20b have the same dimension. The first electrode catalyst layer 20a may have a smaller planar dimension than the first gas diffusion layer 20b.

  The anode electrode 22 is bonded to the surface 18b of the solid polymer electrolyte membrane 18, and the second electrode catalyst layer 22a and the second gas diffusion layer 22b that expose the outer peripheral edge portion 18be of the solid polymer electrolyte membrane 18 in a frame shape. And have. The second electrode catalyst layer 22a and the second gas diffusion layer 22b are set to have the same planar dimensions. The second electrode catalyst layer 22a may have a smaller planar size than the second gas diffusion layer 22b or a larger planar size.

  The first electrode catalyst layer 20a has a larger planar dimension than the second electrode catalyst layer 22a, but the first electrode catalyst layer 20a and the second electrode catalyst layer 22a are set to the same planar dimension. May be. The first electrode catalyst layer 20a and the second electrode catalyst layer 22a may be composed of a plurality of layers.

  The plane dimension of the first gas diffusion layer 20b is set larger than the plane dimension of the second gas diffusion layer 22b, and the first gas diffusion layer 20b covers the entire surface 18a of the solid polymer electrolyte membrane 18.

  The first gas diffusion layer 20b and the second gas diffusion layer 22b are made of carbon paper or the like. In the first electrode catalyst layer 20a and the second electrode catalyst layer 22a, porous carbon particles having a platinum alloy supported thereon are uniformly applied to the surfaces of the first gas diffusion layer 20b and the second gas diffusion layer 22b. Formed.

  As shown in FIGS. 1 and 2, the electrolyte membrane / electrode structure 12 circulates around the outer periphery of the solid polymer electrolyte membrane 18 and is joined to the anode electrode 22 and the cathode electrode 20 to connect the solid polymer electrolyte membrane 18. A resin frame member 24 to be protected is provided. The resin frame member 24 is, for example, PPS (polyphenylene sulfide), PPA (polyphthalamide), PEN (polyethylene naphthalate), PES (polyethersulfone), LCP (liquid crystal polymer), PVDF (polyvinylidene fluoride). , Silicone rubber, fluorine rubber or EPDM (ethylene propylene rubber).

  The resin frame member 24 has a frame shape, is formed thinner than the outermost periphery through the stepped portion, protrudes to the outer peripheral side of the anode electrode 22, and is formed on the outer peripheral edge portion 18 be of the solid polymer electrolyte membrane 18. It has an inner peripheral protrusion 24t that abuts. The outer peripheral edge portion 18be of the solid polymer electrolyte membrane 18 extends outward from the outer peripheral end of the second gas diffusion layer 22b constituting the anode electrode 22.

  As shown in FIG. 1, at one diagonal position of the resin frame member 24, there are a bulging portion 24a protruding toward an oxidant gas inlet communication hole 30a described later, and an oxidant gas outlet communication hole 30b described later. And a bulging portion 24b protruding toward the surface. The electrolyte membrane / electrode structure 12 may be configured not to use the resin frame member 24.

  One end edge of the fuel cell 10 in the arrow B direction (horizontal direction in FIG. 1) communicates with each other in the direction of arrow A, which is the stacking direction, and the oxidant gas inlet communication hole 30a, the cooling medium inlet communication hole 32a, and A fuel gas outlet communication hole 34b is provided. The oxidant gas inlet communication hole 30a supplies an oxidant gas, for example, an oxygen-containing gas. The cooling medium inlet communication hole 32a supplies a cooling medium, and the fuel gas outlet communication hole 34b discharges a fuel gas, for example, a hydrogen-containing gas. The oxidant gas inlet communication hole 30a, the cooling medium inlet communication hole 32a, and the fuel gas outlet communication hole 34b are arranged in the direction of arrow C (vertical direction).

  A fuel gas inlet communication hole 34a, a cooling medium outlet communication hole 32b, and an oxidant gas outlet communication hole 30b are provided at the other edge of the fuel cell 10 in the arrow B direction so as to communicate with each other in the arrow A direction. The fuel gas inlet communication hole 34a supplies fuel gas, the cooling medium outlet communication hole 32b discharges the cooling medium, and the oxidant gas outlet communication hole 30b discharges the oxidant gas. The fuel gas inlet communication hole 34a, the cooling medium outlet communication hole 32b, and the oxidant gas outlet communication hole 30b are arranged in the direction of arrow C.

  As shown in FIGS. 1 and 3, the surface 16a of the second separator 16 facing the electrolyte membrane / electrode structure 12 has a plurality of holes communicating with the oxidant gas inlet communication hole 30a and the oxidant gas outlet communication hole 30b. The oxidant gas flow path 36 is provided. The oxidant gas inlet communication hole 30a and the oxidant gas flow path 36 communicate with each other via a plurality of inlet connection paths 37a. The oxidant gas outlet communication hole 30b and the oxidant gas flow path 36 communicate with each other via a plurality of outlet connection paths 37b.

  As shown in FIG. 4, on the surface 14a of the first separator 14 facing the electrolyte membrane / electrode structure 12, a plurality of fuel gas flow paths communicating with the fuel gas inlet communication hole 34a and the fuel gas outlet communication hole 34b are provided. 38 is formed. The first separator 14 includes a plurality of supply holes 39a that communicate the fuel gas inlet communication hole 34a with the fuel gas flow path 38, and a plurality of fuel gas flow paths 38 that communicate with the fuel gas outlet communication hole 34b. A discharge hole 39b is formed.

  As shown in FIGS. 1 and 5, a cooling medium that communicates with the cooling medium inlet communication hole 32 a and the cooling medium outlet communication hole 32 b between the surface 14 b of the first separator 14 and the surface 16 b of the second separator 16. A flow path 40 is formed.

  As shown in FIGS. 1 and 2, the first seal member 42 is integrated with both surfaces 14 a and 14 b of the first separator 14 around the outer peripheral end portion of the first separator 14. The second seal member 44 is integrated with the surfaces 16 a and 16 b of the second separator 16 around the outer peripheral end portion of the second separator 16.

  For the first seal member 42 and the second seal member 44, for example, EPDM, NBR, fluororubber, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene or acrylic rubber or the like, cushion material Alternatively, an elastic seal member such as a packing material is used.

  As shown in FIGS. 2 and 6, the first seal member 42 is integrated with the surfaces 14a and 14b of the first separator 14, and has a flat seal (base seal) having a uniform thickness along the separator surface. 42a. The first seal member 42 includes a first inner seal member 42 b that is integrated with the surface 14 a and abuts against the resin frame member 24 of the electrolyte membrane / electrode structure 12. The first inner sealing member 42b is arranged around the power generation region as viewed from the stacking direction.

  As shown in FIGS. 1 and 2, the first seal member 42 has a second inner seal member 42c and an outer seal member 42d integrated with the surface 14b of the first separator 14, that is, a double seal structure. In the vicinity of the supply hole portion 39a and the discharge hole portion 39b, the intermediate support member 42e is integrally formed with the first seal member 42 in the shape of an island, located in the middle of the second inner seal member 42c and the outer seal member 42d. Is done.

  As shown in FIG. 6, the intermediate support member 42e is set to be lower than the second inner seal member 42c and the outer seal member 42d by a height t1. The height t1 is set so that the intermediate support member 42e substantially contacts the second separator 16 without elastic deformation in a state where the fuel cell 10 is assembled and a tightening load is applied. The first seal member 42 is located on the surface 14b close to the cooling medium inlet communication hole 32a and the cooling medium outlet communication hole 32b from the cooling medium flow path 40 to the cooling medium inlet communication hole 32a and the cooling medium outlet communication hole. A plurality of projecting portions (rubber bridge portions) 42f extending toward 32b are integrally provided.

  As shown in FIGS. 1 to 3, the second seal member 44 is integrated with both surfaces 16 a and 16 b of the second separator 16 and has a flat seal (base seal) having a uniform thickness along the separator surface. 44a. The second seal member 44 includes a first outer seal member 44 b that is integrated with the surface 16 a and is located outward from the outer peripheral end of the electrolyte membrane / electrode structure 12 and contacts the first separator 14.

  As shown in FIGS. 2 and 5, the second seal member 44 has a second outer seal member 44 c that is integrated with the surface 16 b of the second separator 16. As shown in FIG. 5, the cooling medium inlet communication hole 32 a and the cooling medium outlet communication are provided on the surface 16 b from the cooling medium flow path 40 at a position close to the cooling medium inlet communication hole 32 a and the cooling medium outlet communication hole 32 b. A plurality of protrusions (rubber bridge portions) 44d extending toward the holes 32b are integrally provided. The protrusion 42f and the protrusion 44d are in contact with each other.

  As shown in FIG. 3, the second seal member 44 intersects the extending direction of the protruding portion 44d at a position close to the cooling medium inlet communication hole 32a and the cooling medium outlet communication hole 32b, and the back surface of the protruding portion 44d. A receiving portion 44e for holding the side is provided integrally in a straight line. The intermediate support member 44f is secondly sealed in an island shape inside each receiving portion 44e, that is, between the first outer seal member 44b and the first inner seal member 42b of the first seal member 42. The member 44 is integrally formed.

  The intermediate support member 44f is set to be lower in height than the first outer seal member 44b. The intermediate support member 44f is set lower than the receiving portion 44e by a height t2. The height t2 is set so that the intermediate support member 44f substantially contacts the first separator 14 without being elastically deformed in a state where the fuel cell 10 is assembled and a tightening load is applied.

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

  First, as shown in FIG. 1, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet communication hole 30a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 34a. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the cooling medium inlet communication hole 32a.

  Therefore, the oxidant gas is introduced into the oxidant gas flow path 36 of the second separator 16 from the oxidant gas inlet communication hole 30a, moves in the direction of arrow B, and is supplied to the cathode electrode 20 of the MEA component 12a. . On the other hand, the fuel gas is introduced into the fuel gas flow path 38 of the first separator 14 from the fuel gas inlet communication hole 34a through the supply hole 39a. The fuel gas moves in the direction of arrow B along the fuel gas flow path 38 and is supplied to the anode electrode 22 of the MEA component 12a.

  Accordingly, in each MEA component 12a, the oxidant gas supplied to the cathode electrode 20 and the fuel gas supplied to the anode electrode 22 are electrically supplied in the first electrode catalyst layer 20a and the second electrode catalyst layer 22a. It is consumed by chemical reaction to generate electricity.

  Next, the oxidant gas consumed by being supplied to the cathode electrode 20 is discharged in the direction of arrow A along the oxidant gas outlet communication hole 30b. Similarly, the fuel gas consumed by being supplied to the anode electrode 22 is discharged in the direction of arrow A along the fuel gas outlet communication hole 34b from the discharge hole portion 39b.

  The cooling medium supplied to the cooling medium inlet communication hole 32a is introduced into the cooling medium flow path 40 between the first separator 14 and the second separator 16, and then flows in the direction of arrow B. This cooling medium is discharged from the cooling medium outlet communication hole 32b after cooling the MEA component 12a.

  In this case, in this embodiment, as shown in FIGS. 1 and 6, the intermediate support member 42 e is integrally formed with the first seal member 42 so as to be positioned between the second inner seal member 42 c and the outer seal member 42 d. Has been. For this reason, the distance between the second inner seal member 42c and the outer seal member 42d corresponds to a part where the distance is set relatively large, that is, a part where the first separator 14 is likely to be deformed due to the differential pressure across the separator. An intermediate support member 42e can be provided.

  Further, the intermediate support member 42e is set lower than the second inner seal member 42c and the outer seal member 42d by a height t1. Accordingly, the intermediate support member 42e does not receive a tightening load acting on the fuel cell 10, and can secure a desired seal load.

  Accordingly, it is possible to suppress the deformation of the first separator 14 having the double seal structure in which the second inner seal member 42c and the outer seal member 42d are provided with a simple configuration as much as possible. can get.

  On the other hand, as shown in FIGS. 1 and 3, the second separator 16 is positioned between the first outer seal member 44 b and the first inner seal member 42 b of the first seal member 42, and is respectively an intermediate support member. 44 f is integrally formed with the second seal member 44. For this reason, the effect that it becomes possible to suppress a deformation | transformation of the 2nd separator 16 as much as possible with a simple structure is acquired.

  Further, the intermediate support member 44f is set to have a height dimension lower than that of the first outer seal member 44b and lower than the receiving portion 44e by the height t2. Therefore, the intermediate support member 44f does not receive a tightening load acting on the fuel cell 10, and can secure a desired seal load.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell 12 ... Electrolyte membrane and electrode structure 14, 16 ... Separator 18 ... Solid polymer electrolyte membrane 20 ... Cathode electrode 20a, 22a ... Electrode catalyst layer 20b, 22b ... Gas diffusion layer 22 ... Anode electrode 24 ... Product made from resin Frame member 30a ... Oxidant gas inlet communication hole 30b ... Oxidant gas outlet communication hole 32a ... Cooling medium inlet communication hole 32b ... Cooling medium outlet communication hole 34a ... Fuel gas inlet communication hole 34b ... Fuel gas outlet communication hole 36 ... Oxidant Gas passage 38 ... Fuel gas passage 39a ... Supply hole 39b ... Discharge hole 40 ... Cooling medium passages 42, 44 ... Seal members 42b, 42c ... Inner seal members 42d, 44b, 44c ... Outer seal members 42e, 44f ... Intermediate support members 42f, 44d ... Protrusions

Claims (3)

It has an electrolyte membrane / electrode structure with electrodes provided on both sides of the electrolyte membrane, the electrolyte membrane / electrode structure is sandwiched between a pair of separators, and is provided around the power generation region as viewed from the clamping direction. A double-sealed fuel cell having an inner seal member and an outer seal member provided around the outer side of the inner seal member,
Between the inner seal member and the outer seal member, there is provided an intermediate support member that is integrally formed with at least one of the inner seal member or the outer seal member and has a height dimension lower than that of the one. A fuel cell. The fuel cell according to claim 1, wherein a cooling medium flow path for flowing the cooling medium along the separator surface is formed between the separators adjacent to each other.
The fuel cell according to claim 1, wherein the intermediate support member is formed between the inner seal member and the outer seal member provided on the cooling medium flow path side. The fuel cell according to claim 1, wherein a surface of the separator facing the electrolyte membrane / electrode structure is formed with a reaction gas flow path for allowing a reaction gas to flow along the separator surface,
The fuel cell according to claim 1, wherein the intermediate support member is formed between the inner seal member and the outer seal member provided on the reaction gas flow path side.

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