JP2012226847A - Electrolyte membrane and electrode structure for fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent as much as possible the occurrence of deterioration in an outer peripheral end of a solid polymer electrolyte membrane extended outward from an electrode catalyst layer, with a simple and economical configuration.SOLUTION: An electrolyte membrane-electrode structure 12 comprises: a solid polymer electrolyte membrane 18; and an anode-side electrode 20 and a cathode-side electrode 22 which hold the solid polymer electrolyte membrane 18 therebetween. The anode-side electrode 20 includes an electrode catalyst layer 20a and a gas diffusion layer 20b. On the other hand, the cathode-side electrode 22 includes an electrode catalyst layer 22a and a gas diffusion layer 22b. In the solid polymer electrolyte membrane 18, the Solvent 28a and solvent 28b, which are identical to solvent used during formation of the electrode catalyst layers 20a and 22a, are applied to an end surface 18ae which is exposed to the outside from an outer peripheral part of the anode-side electrode 20, and to an end surface 18be which is close to the cathode-side electrode 22.

Description

  The present invention relates to an electrolyte membrane / electrode structure for a fuel cell in which electrode catalyst layers are provided on both sides of a solid polymer electrolyte membrane.

  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 side electrode and a cathode side 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. The body (MEA) is sandwiched between separators (bipolar plates). Usually, a fuel cell stack in which a predetermined number of fuel cells are stacked is used as, for example, an in-vehicle fuel cell stack.

  In this type of electrolyte membrane / electrode structure, the surface area of the solid polymer electrolyte membrane is configured to be larger than the surface areas of the gas diffusion layer and the catalyst layer laminated on both sides of the solid polymer electrolyte membrane, In some cases, the outer peripheral end face of the molecular electrolyte membrane constitutes a so-called membrane protruding MEA in which the outer peripheral end face of each gas diffusion layer and the catalyst layer protrudes outward.

  In this type of electrolyte membrane / electrode structure, the area of one electrode is configured to be larger than the area of the other electrode, and the end of the one electrode protrudes outward from the end of the other electrode. In other words, a so-called stepped MEA may be configured.

  In the above MEA, the gas permeation amount from the outer peripheral portion protruding outward in the plane direction of the solid polymer electrolyte membrane tends to be larger than the gas permeation amount of the portion coated with the catalyst layer on the inner side in the plane direction. . For this reason, in the outer peripheral edge of the solid polymer electrolyte membrane, a mixture of fuel gas and oxidant gas existing on both sides of the solid polymer electrolyte membrane is easily caused, and the deterioration of the solid polymer electrolyte membrane is promoted. There is a problem that.

  Thus, for example, a polymer electrolyte membrane electrode assembly disclosed in Patent Document 1 is known. This solid polymer electrolyte membrane electrode assembly includes a solid polymer electrolyte membrane, a catalyst layer including a catalyst disposed on both sides of the solid polymer electrolyte membrane, and gas diffusion that supports the catalyst layer on the inner side of the peripheral portion. An electrode comprising a layer.

  The solid polymer electrolyte membrane includes a first region having proton conductivity in the entire thickness direction of the membrane, and a non-porous sheet disposed on the outer peripheral portion of the first region, whereby the thickness of the membrane is increased. The entire length direction has a second region having no proton conductivity. And from the outer edge of a catalyst layer to the outer edge of a gas diffusion layer, it arrange | positions so that it may be located in a 2nd area | region.

Japanese Patent Laid-Open No. 2006-1000026

  However, in Patent Document 1 described above, since a non-porous sheet made of a different material is disposed on the solid polymer electrolyte membrane, the solid polymer electrolyte membrane during power generation partially contains water. An area with a different environment will occur. As a result, the solid polymer electrolyte membrane has a problem that the distribution is easily caused in the permeation amount through which the reaction gas permeates, and the power generation performance is deteriorated.

  The present invention solves this type of problem, and it is possible to cause deterioration at the outer peripheral end portion of the solid polymer electrolyte membrane extending outward from the electrode catalyst layer with a simple and economical configuration. It is an object of the present invention to provide an electrolyte membrane / electrode structure for a fuel cell that can be blocked.

  The present invention relates to an electrolyte membrane / electrode structure for a fuel cell in which electrode catalyst layers are provided on both sides of a solid polymer electrolyte membrane. In this electrolyte membrane / electrode structure, the outer periphery of the solid polymer electrolyte membrane is provided with a protruding end extending outward from the electrode catalyst layer, and at least one surface of the protruding end is Solvent is applied.

  In the fuel cell electrolyte membrane / electrode structure, the solvent is preferably the same solvent as that used in the electrode catalyst layer.

  According to the present invention, the solvent is applied to the outer peripheral portion of the solid polymer electrolyte membrane. For this reason, in the solid polymer electrolyte membrane, the reaction gas permeation amount in the catalyst region and the protruding end region can be made equal. Thereby, it becomes possible to prevent deterioration from occurring at the outer peripheral end portion of the solid polymer electrolyte membrane extending outward from the electrode catalyst layer as much as possible with a simple and economical configuration.

1 is an exploded perspective view of a main part of a fuel cell incorporating a fuel cell electrolyte membrane / electrode structure according to a first embodiment of the present invention. FIG. 2 is a sectional view of the fuel cell taken along line II-II in FIG. 1. FIG. 4 is a partial cross-sectional explanatory view of an electrolyte membrane / electrode structure constituting the fuel cell. It is front explanatory drawing of the said electrolyte membrane and electrode structure. It is explanatory drawing at the time of apply | coating an electrode catalyst layer to a solid polymer electrolyte membrane. It is explanatory drawing at the time of apply | coating a solvent to the outer peripheral edge part of a solid polymer electrolyte membrane. It is explanatory drawing at the time of joining a gas diffusion layer to a solid polymer electrolyte membrane. It is process explanatory drawing for manufacturing the said electrolyte membrane and electrode structure. It is explanatory drawing of the film | membrane intensity | strength of the said conventional electrolyte membrane electrode structure. It is explanatory drawing of the film | membrane intensity | strength of the said electrolyte membrane and electrode structure of 1st Embodiment. It is another process explanatory drawing for manufacturing the said electrolyte membrane and electrode structure. It is a principal part disassembled perspective explanatory view of the fuel cell incorporating the electrolyte membrane and electrode structure for fuel cell according to the second embodiment of the present invention. It is XIII-XIII sectional view explanatory drawing in FIG. 12 of the said fuel cell.

  As shown in FIGS. 1 and 2, the polymer electrolyte fuel cell 10 incorporates an electrolyte membrane / electrode structure 12 for a fuel cell according to the first embodiment of the present invention. The electrolyte membrane / electrode structure 12 is sandwiched between the first separator 14 and the second separator 16.

  The 1st separator 14 and the 2nd separator 16 are comprised, for example with the steel plate, the stainless steel plate, the aluminum plate, the plating processing steel plate, or the metal plate etc. which performed the surface treatment for corrosion prevention on the metal surface. The first separator 14 and the second separator 16 have a rectangular planar shape, and are formed into a concavo-convex shape by pressing a metal thin plate into a wave shape. In addition, you may comprise the 1st separator 14 and the 2nd separator 16 with a carbon separator, for example.

  The electrolyte membrane / electrode structure 12 includes, for example, a solid polymer electrolyte membrane 18 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode side electrode 20 and a cathode side electrode 22 that sandwich the solid polymer electrolyte membrane 18. With. The anode side electrode 20 has a smaller surface area than the cathode side electrode 22 and the solid polymer electrolyte membrane 18 (step MEA).

  The solid polymer electrolyte membrane 18 uses an HC (hydrocarbon) electrolyte in addition to a fluorine electrolyte. In the first embodiment, for example, the solid polymer electrolyte membrane 18 may have a structure in which the main chain has a polyphenylene structure, and has a side chain having a sulfonic acid group and a side chain having a nitrogen-containing heterocyclic group.

  As shown in FIG. 3, the anode-side electrode 20 is in contact with one surface 18a of the solid polymer electrolyte membrane 18, and the electrode catalyst layer 20a and the gas that expose the outer periphery of the solid polymer electrolyte membrane 18 in a frame shape. A diffusion layer 20b is provided. The gas diffusion layer 20b is made of carbon paper, carbon cloth or the like, and porous carbon particles having a platinum alloy supported on the surface of the gas diffusion layer 20b are uniformly applied to form the electrode catalyst layer 20a. .

  The cathode side electrode 22 is provided with an electrode catalyst layer 22 a and a gas diffusion layer 22 b that are in contact with the other surface 18 b of the solid polymer electrolyte membrane 18, similarly to the anode side electrode 20 described above. The electrode catalyst layers 20a and 22a may be composed of a plurality of layers.

  The plane of the gas diffusion layer 22b is set to be larger than the plane of the gas diffusion layer 20b, and the gas diffusion layer 22b protrudes from the outer periphery of the electrode catalyst layer 22a to the entire other surface 18b of the solid polymer electrolyte membrane 18. Cover.

  The end of the electrode catalyst layer 20a is set at a position protruding by a distance H over the entire outer circumference in the surface direction of the solid polymer electrolyte membrane 18 from the end of the electrode catalyst layer 22a. It should be noted that the size relationship between the end portions of the electrode catalyst layer 20a and the end portions of the electrode catalyst layer 22a may be set oppositely on adjacent sides. The magnitude relationship between the anode side electrode 20 and the cathode side electrode 22 may be reversed. An adhesive layer 26 a is provided between the gas diffusion layer 20 b protruding from the outer periphery of the electrode catalyst layer 20 a and the solid polymer electrolyte membrane 18. An adhesive layer 26 b is provided between the gas diffusion layer 22 b protruding from the outer periphery of the electrode catalyst layer 22 a and the solid polymer electrolyte membrane 18. For the adhesive layers 26a and 26b, for example, a fluorine-based adhesive can be used.

  As will be described later, the solid polymer electrolyte membrane 18 is formed on the end face 18ae exposed from the outer periphery of the electrode catalyst layer 20a of the anode side electrode 20 and the end face 18be of the cathode side electrode 22 on the electrode catalyst layer 22a side, as will be described later. The same solvents 28a and 28b as those used in forming the layers 20a and 22a are applied (see FIG. 4). At that time, the solvents 28a and 28b are applied without gaps from the ends of the electrode catalyst layers 20a and 22a.

  As the solvents 28a and 28b, for example, alcohol solvents are used, and specifically, a mixed liquid of water, n-propyl alcohol and ethanol. In addition, you may use the solvent different from the solvent used for the electrode catalyst layers 20a and 22a. The end surface 18be on the solid polymer electrolyte membrane 18 side may be coated with a solvent 28b as necessary, and may be unnecessary. What is necessary is just to apply | coat to at least one side.

  As shown in FIG. 1, one end edge of the fuel cell 10 in the direction of arrow B (horizontal direction in FIG. 1) communicates with each other in the direction of arrow A, which is the stacking direction, and contains an oxidant gas such as oxygen An oxidant gas inlet communication hole 30a for supplying gas, a cooling medium inlet communication hole 32a for supplying a cooling medium, and a fuel gas outlet communication hole 34b for discharging a fuel gas, for example, a hydrogen-containing gas, Arranged in the direction of arrow C (vertical direction).

  The other end edge of the fuel cell 10 in the direction of arrow B communicates with each other in the direction of arrow A, a fuel gas inlet communication hole 34a for supplying fuel gas, and a cooling medium outlet communication hole for discharging the cooling medium. 32b and an oxidant gas outlet communication hole 30b for discharging the oxidant gas are arranged in the direction of arrow C.

  An oxidant gas flow path 36 communicating with the oxidant gas inlet communication hole 30a and the oxidant gas outlet communication hole 30b is provided on the surface 16a of the second separator 16 facing the electrolyte membrane / electrode structure 12.

  A fuel gas passage 38 communicating with the fuel gas inlet communication hole 34 a and the fuel gas outlet communication hole 34 b is formed on the surface 14 a of the first separator 14 facing the electrolyte membrane / electrode structure 12. Between the surface 14 b of the first separator 14 and the surface 16 b of the second separator 16, a cooling medium flow path 40 communicating with the cooling medium inlet communication hole 32 a and the cooling medium outlet communication hole 32 b is formed.

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

  As shown in FIG. 2, the first seal member 42 includes a first convex seal 42 a that contacts the solid polymer electrolyte membrane 18 exposed to the outside of the electrolyte membrane / electrode structure 12, the first separator 14, and the second seal member 42. A second convex seal 42b interposed between the separator 16 and the separator 16; The second seal member 44 constitutes a flat seal. Instead of the second convex seal 42b, the second seal member 44 may be provided with a convex seal (not shown).

  The first and second sealing members 42 and 44 include, for example, EPDM, NBR, fluorine rubber, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene or acrylic rubber, a cushioning material, Alternatively, a packing material is used.

  As shown in FIG. 1, the first separator 14 has a supply hole portion 46 that communicates the fuel gas inlet communication hole 34a with the fuel gas passage 38, and the fuel gas passage 38 communicates with the fuel gas outlet communication hole 34b. A discharge hole 48 is formed.

  A method of manufacturing the electrolyte membrane / electrode structure 12 in the fuel cell 10 configured as described above will be described below.

  First, as shown in FIG. 5, after the solid polymer electrolyte membrane 18 is formed in a rectangular shape, a catalyst paste is applied to each of the surfaces 18a and 18b of the solid polymer electrolyte membrane 18 to thereby form electrodes. A catalyst layer 20a and an electrode catalyst layer 22a are formed.

  The electrode catalyst layer 20a and the electrode catalyst layer 22a include, for example, an ion conductive binder and catalyst particles made of carbon particles supporting Pt, and an alcohol solvent, for example, a mixed solution of water, n-propyl alcohol, and ethanol. In addition, a catalyst paste is prepared by mixing at a constant ratio. Further, the catalyst paste is formed by screen printing on both surfaces of the solid polymer electrolyte membrane 18 and then drying the catalyst paste.

  Next, as shown in FIG. 6, the end surface 18ae exposed to the outside of the electrode catalyst layer 20a on the surface 18a of the solid polymer electrolyte membrane 18, and outward from the end of the electrode catalyst layer 22a on the surface 18b as necessary. 18be exposed to each is coated with an alcohol catalyst, for example, solvents 28a and 28b made of a mixture of water, n-propyl alcohol and ethanol. In addition, if it is an alcohol-type solvent, a component will not necessarily be limited.

  Then, after the solvents 28a and 28b are dried, as shown in FIG. 7, adhesive layers 26a and 26b are applied to the outer peripheral edge portions of the gas diffusion layers 20b and 22b by screen printing.

  The gas diffusion layer 20b is pressed toward the surface 18a of the solid polymer electrolyte membrane 18, while the gas diffusion layer 22b is pressed toward the surface 18b of the solid polymer electrolyte membrane 18. The gas diffusion layers 20b and 22b are integrated with the solid polymer electrolyte membrane 18 by performing a hot press process, and the electrolyte membrane / electrode structure 12 is manufactured (see FIG. 3).

  As shown in FIG. 8, the step of manufacturing the electrolyte membrane / electrode structure 12 includes an electrode coating step (step S1) for forming electrode catalyst layers 20a, 22a on the surfaces 18a, 18b of the solid polymer electrolyte membrane 18, A drying process (step S2) for drying the electrode catalyst layers 20a and 22a, a solvent application process (step S3) for applying the solvents 28a and 28b to the end faces 18ae and 18be of the solid polymer electrolyte membrane 18, and the solvents 28a and 28b. A drying process (step S4) for drying and a gas diffusion layer combining process (step S5) for integrating the gas diffusion layers 20b and 22b are basically included.

  Here, step S3 may include a step (step S11) of applying the solvent 28a only to the end surface 18ae of the one surface 18a (anode side surface) of the solid polymer electrolyte membrane 18. In step S3, the solvent 28b may be applied only to the end surface 18be of the other surface 18b (cathode side surface) of the solid polymer electrolyte membrane 18 (step S21).

  Further, in step S3, the solvent 28a is applied only to one end face 18ae (step S31), and after the solvent 28a is dried (step S32), the solvent 28b is applied only to the other end face 18be (step S33). May be.

  Furthermore, in step S3, the solvent 28b is applied only to the other end face 18be of the solid polymer electrolyte membrane 18 (step S41), and after the solvent 28b is dried, the solvent 28a is applied only to one end face 18ae ( Step S43) may be performed.

  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.

  For this reason, 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 arrow B direction, and the cathode side electrode 22 of the electrolyte membrane / electrode structure 12. To be supplied. On the other hand, the fuel gas is introduced from the fuel gas inlet communication hole 34 a through the supply hole 46 into the fuel gas flow path 38 of the first separator 14. The fuel gas moves in the direction of arrow B along the fuel gas flow path 38 and is supplied to the anode side electrode 20 of the electrolyte membrane / electrode structure 12.

  Therefore, in the electrolyte membrane / electrode structure 12, the oxidant gas supplied to the cathode side electrode 22 and the fuel gas supplied to the anode side electrode 20 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 22 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 side electrode 20 passes through the discharge hole portion 48 and is discharged in the direction of arrow A along the fuel gas outlet communication hole 34b.

  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. The cooling medium is discharged from the cooling medium outlet communication hole 32b after the electrolyte membrane / electrode structure 12 is cooled.

  In this case, in the first embodiment, the electrode catalyst is formed on at least the end surface 18ae of the solid polymer electrolyte membrane 18 exposed to the outside of the anode side electrode 20 (end surface 18be exposed to the outside of the cathode side electrode 22 as necessary). The same solvent 28a (28b) as that used when forming the layer 20a (22a) or a different solvent is applied. For this reason, in the polymer electrolyte membrane 18, the gas permeation of the fuel gas (and the oxidant gas) in the catalyst region of the anode side electrode 20 (and the cathode side electrode 22) and the protruding end region of the end face 18ae (and 18be). The amount can be made equal.

  Here, FIG. 9 shows the film strength distribution of the electrolyte membrane / electrode structure 12pr in which the solvent is not applied to the outer periphery of the normal solid polymer electrolyte membrane 18pr. In the electrolyte membrane / electrode structure 12pr, the molecular orientation of the solid polymer electrolyte membrane 18pr changes when the solvent penetrates into the solid polymer electrolyte membrane 18pr in the electrode application step.

  Accordingly, the gas diffusibility changes from that of the solid polymer electrolyte membrane 18pr before the electrode coating step within the electrode coating range of the solid polymer electrolyte membrane 18pr. On the other hand, the same gas diffusibility as that before the electrode application step is maintained in the outer peripheral portion (outside the electrode application range) of the solid polymer electrolyte membrane 18pr. As a result, in the conventional solid polymer electrolyte membrane 18pr, there are portions with different gas diffusivities in the surface, the mixing ratio of hydrogen gas and air as the fuel gas changes, and local deterioration occurs. .

  In FIG. 9, the in-plane film strength has a relationship of TF1 <TF2 <TF3 <TF4 <TF5. For this reason, particularly in the solid polymer electrolyte membrane 18pr, the strength decrease (TF1) is most noticeable particularly at the outer peripheral edge, and the phenomenon that the durability of the solid polymer electrolyte membrane 18pr is reduced has become apparent.

  In contrast, in the first embodiment, as shown in FIG. 10, the gas permeability over the entire surface of the solid polymer electrolyte membrane 18 is made uniform. Therefore, the solid polymer electrolyte membrane 18 is not locally degraded, and the durability is improved.

  Thereby, in the first embodiment, with a simple and economical configuration, it is possible to prevent deterioration at the outer peripheral end of the solid polymer electrolyte membrane 18 as much as possible, and to improve durability. The effect that it can be obtained.

  Incidentally, the electrolyte membrane / electrode structure 12 according to the first embodiment can be manufactured by the manufacturing process shown in FIG.

  In this manufacturing process, first, the entire surface 18a, 18b of the solid polymer electrolyte membrane 18 is coated with the solvent 28a, 28b over the entire surface, respectively (step S101), and the solvent 28a, 28b is dried. A drying step (step S102), an electrode coating step (step S103) for applying the electrode catalyst layers 20a, 22a to the surfaces 18a, 18b, a drying step (step S104) for drying the electrode catalyst layers 20a, 22a, and a gas diffusion layer A gas diffusion layer combining step (step S105) for manufacturing the electrolyte membrane / electrode structure 12 by bonding 20b and 22b to both surfaces of the solid polymer electrolyte membrane 18 is provided.

  Thereby, similarly to the manufacturing process shown in FIG. 8, a desired electrolyte membrane / electrode structure 12 can be efficiently manufactured.

  FIG. 12 is an exploded perspective view of a principal part of a polymer electrolyte fuel cell 62 incorporating a fuel cell electrolyte membrane / electrode structure 60 according to a 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.

  In the fuel cell 62, the electrolyte membrane / electrode structure 60 is sandwiched between the first separator 64 and the second separator 66. The upper end edge of the fuel cell 62 in the arrow C direction (vertical direction) 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 the fuel gas inlet communication. The holes 34a are arranged in the arrow B direction.

  The fuel gas outlet communication hole 34b, the coolant outlet communication hole 32b, and the oxidant gas outlet communication hole 30b communicate with each other in the arrow A direction at the lower edge of the fuel cell 62 in the arrow C direction. Arranged and provided.

  An oxidant gas flow path 36 communicating with the oxidant gas inlet communication hole 30a and the oxidant gas outlet communication hole 30b is provided on the surface 64a of the first separator 64 facing the electrolyte membrane / electrode structure 60 along the vertical direction. Provided.

  A fuel gas channel 38 communicating with the fuel gas inlet communication hole 34a and the fuel gas outlet communication hole 34b is provided along the vertical direction on the surface 66a of the second separator 66 facing the electrolyte membrane / electrode structure 60. .

  A cooling medium that connects the cooling medium inlet communication hole 32a and the cooling medium outlet communication hole 32b between the surface 64b of the first separator 64 and the surface 66b of the second separator 66 constituting the fuel cells 62 adjacent to each other. A flow path 40 is provided along the vertical direction.

  The first seal member 68 is integrally or individually provided on the surfaces 64 a and 64 b of the first separator 64, and the second seal member 70 is integrally formed on the surfaces 66 a and 66 b of the second separator 66. Or it is provided separately.

  As shown in FIG. 13, the electrolyte membrane / electrode structure 60 includes, for example, a solid polymer electrolyte membrane 74 in which a perfluorosulfonic acid thin film is impregnated with water, and a cathode side sandwiching the solid polymer electrolyte membrane 74 An electrode 76 and an anode side electrode 78 are provided. The solid polymer electrolyte membrane 74 is similar to the solid polymer electrolyte membrane 18 of the first embodiment. For example, the main chain has a polyphenylene structure, and the side chain has a sulfonic acid group and a nitrogen-containing heterocyclic group. A structure having a chain may also be used.

  The cathode side electrode 76 and the anode side electrode 78 have the same surface area (outside dimension), and the solid polymer electrolyte membrane 74 has a larger surface area (outside dimension) than the cathode side electrode 76 and the anode side electrode 78. Have. Both end faces 74ae and 74be of the solid polymer electrolyte membrane 74 extend outward from the ends of the cathode side electrode 76 and the anode side electrode 78.

  The cathode side electrode 76 and the anode side electrode 78 are electrode catalyst layers 76a and 78a joined to both surfaces 74a and 74b of the solid polymer electrolyte membrane 74, and a gas diffusion layer laminated on the electrode catalyst layers 76a and 78a. (Porous diffusion layers) 76b and 78b are provided.

  An adhesive layer 80a is provided between the gas diffusion layer 76b protruding from the outer periphery of the electrode catalyst layer 76a and the solid polymer electrolyte membrane 74. An adhesive layer 80b is provided between the gas diffusion layer 78b protruding from the outer periphery of the electrode catalyst layer 78a and the solid polymer electrolyte membrane 74.

  The electrolyte membrane / electrode structure 60 configured as described above is manufactured in the same manner as the electrolyte membrane / electrode structure 12 described above. Specifically, the electrolyte membrane / electrode structure 60 is manufactured by the manufacturing process shown in FIG. 8 or the manufacturing process shown in FIG. 11, and the end surfaces 74ae and 74be of the solid polymer electrolyte membrane 74 are respectively formed on the end surfaces 74ae and 74be. After the solvents 28a and 28b are applied, a drying process is performed.

  Accordingly, the solid polymer electrolyte membrane 74 makes the reaction gas permeation amount equal between the catalyst region where the electrode catalyst layers 76a and 78a are applied and the protruding end region where the electrode catalyst layers 76a and 78a are not provided. be able to.

  As a result, in the second embodiment, with the simple and economical configuration, deterioration occurs on the outer peripheral end surfaces 74ae and 74be of the solid polymer electrolyte membrane 74 extending outward from the electrode catalyst layers 76a and 78a. The same effects as those of the first embodiment can be obtained, such as being able to prevent as much as possible.

DESCRIPTION OF SYMBOLS 10, 62 ... Fuel cell 12, 60 ... Electrolyte membrane and electrode structure 14, 16, 64, 66 ... Separator 18, 74 ... Solid polymer electrolyte membrane 18ae, 18be, 74ae, 74be ... End face 20, 78 ... Anode side electrode 20a, 22a, 76a, 78a ... Electrode catalyst layers 20b, 22b, 76b, 78b ... Gas diffusion layers 22, 76 ... Cathode side electrodes 26a, 26b, 80a, 80b ... Adhesive layers 28a, 28b ... Solvent 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 flow path 38 ... Fuel gas flow Path 40 ... Cooling medium flow path

Claims (2)

An electrolyte membrane / electrode structure for a fuel cell in which an electrode catalyst layer is provided on both sides of a solid polymer electrolyte membrane,
On the outer periphery of the solid polymer electrolyte membrane is provided with a protruding end extending outward from the electrode catalyst layer,
An electrolyte membrane / electrode structure for a fuel cell, wherein a solvent is applied to at least one surface of the protruding end portion.   2. The electrolyte membrane / electrode structure for a fuel cell according to claim 1, wherein the solvent is the same solvent as that used for the electrode catalyst layer.

Images