JP2013161741A - Electrolyte membrane for fuel cell, and electrode structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent reaction gas from entering an end portion of a solid polymer electrolyte membrane provided with only one catalyst layer, and to effectively suppress the deterioration of the end portion of the solid polymer electrolyte membrane by preventing the accumulation of the reaction gas.SOLUTION: An electrolyte membrane/electrode structure 10a configuring a fuel cell 12 is equipped with an anode electrode 20 and a cathode electrode 22 for clipping a solid polymer electrolyte membrane 18. An electrode catalyst layer 20a of the anode electrode 20 and an electrode catalyst layer 22a of the cathode electrode 22 have different surface dimensions. Between the solid polymer electrolyte membrane 18 and a gas diffusion layer 22b, a frame-shaped film member 24 superimposed with an outer peripheral end portion 22ae of the electrode catalyst layer 22a and having a part 24a is provided. On the gas diffusion layer 20b side, a reaction gas permeation area 53 is provided around the outer periphery of the electrode catalyst layer 20a.

Description

  The present invention provides an electrolyte membrane for a fuel cell in which an anode electrode and a cathode electrode are provided on both sides of a solid polymer electrolyte membrane, and the surface dimensions of the anode catalyst layer and the cathode catalyst layer are set to different dimensions. -It relates to an 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 having a catalyst layer (electrode catalyst layer) and a gas diffusion layer (porous carbon) are disposed on both sides of a solid polymer electrolyte membrane ( MEA) is sandwiched between separators (bipolar plates). A predetermined number of fuel cells are stacked to constitute a fuel cell stack, and are used as, for example, an in-vehicle fuel cell stack.

  In the electrolyte membrane / electrode structure, one electrode is set to have a smaller surface area than the solid polymer electrolyte membrane, and the other electrode is set to the same surface area as the solid polymer electrolyte membrane. An MEA may be configured.

  For example, in a polymer electrolyte fuel cell disclosed in Patent Document 1, an anode electrode 2 and a cathode electrode 3 are disposed on both sides of a solid polymer electrolyte membrane 1 as shown in FIG. The anode electrode 2 and the cathode electrode 3 are sandwiched between separators 5 and 6 with gas seal portions 4a and 4b arranged on the outer peripheral portions thereof.

  The anode electrode 2 has an anode electrode catalyst layer 2a disposed on one surface of the solid polymer electrolyte membrane 1, and an electrode substrate (diffusion layer) 2b disposed outside the anode electrode catalyst layer 2a. ing. The cathode electrode 3 includes a cathode electrode catalyst layer 3a disposed on the other surface of the solid polymer electrolyte membrane 1, and an electrode base material (diffusion layer) 3b disposed outside the cathode electrode catalyst layer 3a. ing.

  The anode electrode catalyst layer 2a and the electrode substrate 2b have the same outer dimensions, and the cathode electrode catalyst layer 3a and the electrode substrate 3b have the same outer dimensions. Further, the anode electrode 2 is set to have a larger outer dimension than the cathode electrode 3.

  The separator 5 is formed with a fuel gas passage 5 a for supplying fuel gas to the anode electrode 2, and the separator 6 is provided with an oxidant gas passage 6 a for supplying oxidant gas to the cathode electrode 3. Is formed.

JP 2009-99265 A

  In the above-mentioned Patent Document 1, the outer dimension of the cathode electrode catalyst layer 3a is set smaller than the outer dimension of the anode electrode catalyst layer 2a, and one of the solid polymer electrolyte membranes 1 is included in the electrolyte membrane / electrode structure. A so-called half-electrode portion 7 is provided, in which a catalyst layer is provided only on this surface. For this reason, a part of the oxidant gas supplied to the oxidant gas flow path 6a may penetrate the electrode base material 3b which is a porous body and enter the half electrode part 7.

Accordingly, hydrogen and oxygen react with each other at the half electrode portion 7 to easily generate hydrogen peroxide (H ₂ O ₂ ) (H ₂ + O ₂ → H ₂ O ₂ ). This hydrogen peroxide is decomposed on the carbon support or platinum (Pt) in the electrode, and for example, a hydroxy radical (.OH) is generated. Thereby, there exists a problem of degrading the solid polymer electrolyte membrane 1 and an electrode.

  Moreover, on the anode electrode 2 side, the fuel gas passage 5a is not provided in the separator 5 facing the half electrode portion 7 in the stacking direction, and is closed. For this reason, there is a problem that the oxidant gas that has entered the half-electrode portion 7 stays in the half-electrode portion 7 and the above deterioration reaction is promoted.

  The present invention solves this type of problem and prevents the reaction gas from entering the end of the solid polymer electrolyte membrane provided with only one catalyst layer, and also prevents the reaction gas from staying. Accordingly, an object of the present invention is to provide a fuel cell electrolyte membrane / electrode structure capable of effectively suppressing deterioration of the end portion of the solid polymer electrolyte membrane.

  In the present invention, an anode electrode having an anode catalyst layer and an anode diffusion layer having a surface dimension larger than that of the anode catalyst layer is provided on one surface of the solid polymer electrolyte membrane, and the other side of the solid polymer electrolyte membrane is provided. The surface is provided with a cathode electrode having a cathode catalyst layer and a cathode diffusion layer having a surface dimension larger than that of the cathode catalyst layer, and the surface dimension of the anode catalyst layer is different from the surface dimension of the cathode catalyst layer. The present invention relates to a fuel cell electrolyte membrane / electrode structure to be set.

  In this fuel cell electrolyte membrane / electrode structure, there is a frame between the solid polymer electrolyte membrane and the cathode diffusion layer or anode diffusion layer that overlaps with the outer peripheral edge of the cathode catalyst layer or anode catalyst layer. The reaction gas non-permeability region is provided, and the reaction gas permeation region is provided around the counter electrode catalyst layer on the diffusion layer side of the counter electrode.

  Further, in this fuel cell electrolyte membrane / electrode structure, the reaction gas impervious region has a frame-shaped inner peripheral side end portion overlapping with the outer peripheral end portion of the anode catalyst layer or the cathode catalyst layer in the thickness direction. It is preferable to have.

  According to the present invention, since the frame-like reaction gas impervious region is provided so as to overlap with the outer peripheral end of the cathode catalyst layer or the anode catalyst layer, the solid polymer electrolyte membrane is provided from the cathode electrode side or the anode electrode side. There is no contact with the reaction gas. In addition, on the diffusion layer side of the counter electrode, a reaction gas permeation region is provided around the outer periphery of the counter electrode catalyst layer. Therefore, the reaction gas does not stay on the counter electrode side, and the reaction gas can be discharged smoothly.

  As a result, it is possible to effectively and reliably prevent the end of the solid polymer electrolyte membrane from being deteriorated by the deterioration promoting substance generated by the reaction between the oxidant gas and the fuel gas.

It is a principal part disassembled perspective explanatory view of the polymer electrolyte fuel cell in which the resin membrane-attached electrolyte membrane / electrode structure according to the first embodiment of the present invention is incorporated. FIG. 2 is a sectional view of the fuel cell taken along line II-II in FIG. 1. It is principal part cross-sectional explanatory drawing of the said electrolyte membrane and electrode structure with a resin frame. It is explanatory drawing of one surface of the said electrolyte membrane with a resin frame and an electrode structure. It is front explanatory drawing of the 1st separator which comprises the said fuel cell. It is sectional explanatory drawing of the method of manufacturing the said electrolyte membrane and electrode structure with a resin frame. It is a section explanatory view of a polymer electrolyte fuel cell in which an electrolyte membrane-electrode structure with a resin frame according to a second embodiment of the present invention is incorporated. It is explanatory drawing of the other reactive gas impermeable area | region used instead of a film member. It is a section explanatory view of a polymer electrolyte fuel cell in which an electrolyte membrane electrode assembly with a resin frame concerning a 3rd embodiment of the present invention is built. It is a section explanatory view of a polymer electrolyte fuel cell in which an electrolyte membrane and electrode structure with a resin frame concerning a 4th embodiment of the present invention is built. 2 is an explanatory diagram of a polymer electrolyte fuel cell disclosed in Patent Document 1. FIG.

  As shown in FIGS. 1 and 2, an electrolyte membrane / electrode structure 10 with a resin frame according to a first embodiment of the present invention is incorporated into a rectangular polymer electrolyte fuel cell 12 and a plurality of the above Fuel cells 12 are stacked in the direction of arrow A to form a fuel cell stack.

  In the fuel cell 12, the electrolyte membrane / electrode structure 10 with a resin frame is sandwiched between the first separator 14 and the second separator 16. The first separator 14 and the second separator 16 have a vertically long rectangular shape, for example, a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, or a metal plate that has been subjected to anticorrosion surface treatment on its metal surface, It is composed of a carbon member or the like.

  As shown in FIGS. 2 and 3, the electrolyte membrane / electrode structure 10 having a rectangular resin frame includes an electrolyte membrane / electrode structure 10 a, and the electrolyte membrane / electrode structure 10 a is, for example, perfluoro It has a solid polymer electrolyte membrane 18 in which a sulfonic acid thin film is impregnated with water, and an anode electrode 20 and a cathode 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 20 has a smaller surface area than the solid polymer electrolyte membrane 18 and the cathode electrode 22.

  The anode electrode 20 includes an electrode catalyst layer (anode catalyst layer) 20a joined to one surface 18a of the solid polymer electrolyte membrane 18, and a gas diffusion layer (anode diffusion layer) 20b laminated on the electrode catalyst layer 20a. Is provided. As shown in FIG. 3, the outer peripheral end 20be of the gas diffusion layer 20b protrudes outward (outward in the direction of arrow C) from the outer peripheral end 20ae of the electrode catalyst layer 20a, and the gas diffusion layer 20b The outer dimension is set smaller than the outer dimension of the solid polymer electrolyte membrane 18.

  The cathode electrode 22 includes an electrode catalyst layer (cathode catalyst layer) 22a joined to the surface 18b of the solid polymer electrolyte membrane 18, and a gas diffusion layer (cathode diffusion layer) 22b laminated on the electrode catalyst layer 22a. . The outer peripheral end 22ae of the electrode catalyst layer 22a is spaced inward (inward in the direction of arrow C) from the outer peripheral end 20ae of the electrode catalyst layer 20a, and the outer peripheral end 22be of the gas diffusion layer 22b is a solid polymer. The outer dimension is set to be the same (or less than the same) as the outer dimension of the electrolyte membrane 18.

  The electrode catalyst layers 20a and 22a form catalyst particles in which platinum particles are supported on carbon black, use a polymer electrolyte as an ion conductive binder, and uniformly mix the catalyst particles in a solution of the polymer electrolyte. The catalyst paste produced in this way is configured by printing, coating or transferring on both surfaces 18a, 18b of the solid polymer electrolyte membrane 18. The gas diffusion layers 20b and 22b are made of carbon paper or the like, and the plane dimension of the gas diffusion layer 22b is set larger than the plane dimension of the gas diffusion layer 20b.

  The cathode electrode 22 has a frame-shaped film member (reactive gas non-reactive) having an overlap portion 24a and an outer peripheral end 22ae of the electrode catalyst layer 22a between the surface 18b of the solid polymer electrolyte membrane 18 and the gas diffusion layer 22b. A transmission region) 24 is provided. The film member 24 is made of a material having a gas permeability lower than that of the solid polymer electrolyte membrane 18, and for example, PPS (polyphenylene sulfide), PPA (polyphthalamide), PEN (polyethylene naphthalate), PES (polyethersulfur). Phon), LCP (liquid crystal polymer), PVDF (polyvinylidene fluoride), silicone rubber, fluorine rubber or EPDM (ethylene propylene rubber).

  As shown in FIGS. 1 to 4, the resin membrane-attached electrolyte membrane / electrode structure 10 circulates around the outer periphery of the solid polymer electrolyte membrane 18 and is joined to the anode electrode 20 and the cathode electrode 22. 26. Examples of the resin frame member 26 include 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 26 has a thin-walled inner peripheral bulging portion 26 a that protrudes toward the outer peripheral side of the anode electrode 20 and abuts on the outer peripheral edge of the solid polymer electrolyte membrane 18. The inner circumferential bulging portion 26a has the same thickness as the anode electrode 20, and substantially the same thickness as the gas diffusion layer 20b.

  The inner peripheral bulging portion 26 a of the resin frame member 26 and the outer peripheral edge portion of the solid polymer electrolyte membrane 18 are bonded by an adhesive layer 27. For the adhesive layer 27, for example, an ester-based or urethane-based hot melt adhesive is used. The resin frame member 26 and the gas diffusion layer 20b of the anode electrode 20 are integrated by a resin impregnated portion 28a, while the resin frame member 26 and the gas diffusion layer 22b of the cathode electrode 22 are integrated with a resin impregnated portion 28b. Are integrated.

  The adhesive layer 27 is formed in a frame shape over the entire circumference of the outer peripheral edge of the solid polymer electrolyte membrane 18. The resin impregnated portion 28a is formed in a frame shape over the entire circumference of the gas diffusion layer 20b of the anode electrode 20, and the resin impregnated portion 28b extends over the entire circumference of the gas diffusion layer 22b constituting the cathode electrode 22. It is formed in a frame shape.

  As shown in FIG. 1, an inlet buffer portion 29 a corresponding to an inlet side of a fuel gas flow path, which will be described later, is provided on the upper edge of the surface 26 as of the resin electrode member 26 on the anode electrode 20 side. The surface 26as of the resin frame member 26 is provided with an outlet buffer portion 29b corresponding to the outlet side of the fuel gas flow path at the lower edge. The inlet buffer unit 29a and the outlet buffer unit 29b are configured by a plurality of protrusions.

  As shown in FIG. 4, the surface 26cs on the cathode electrode 22 side of the resin frame member 26 is provided with an inlet buffer portion 29c corresponding to the inlet side of the oxidant gas flow path described later at the upper edge. The surface 26cs of the resin frame member 26 is provided with an outlet buffer portion 29d corresponding to the outlet side of the oxidant gas flow path at the lower end edge. The inlet buffer portion 29c and the outlet buffer portion 29d are configured by a plurality of protrusions.

  As shown in FIG. 1, the upper edge of the fuel cell 12 in the direction of arrow C (the gravity direction in FIG. 1) communicates with each other in the direction of arrow A, which is the stacking direction. An oxidant gas inlet communication hole 30a for supplying a gas, a cooling medium inlet communication hole 32a for supplying a cooling medium, and a fuel gas inlet communication hole 34a for supplying a fuel gas, for example, a hydrogen-containing gas, Arranged in the direction of arrow B (horizontal direction).

  The lower end edge of the fuel cell 12 in the direction of arrow C communicates with each other in the direction of arrow A, the fuel gas outlet communication hole 34b for discharging the fuel gas, and the cooling medium outlet communication hole 32b for discharging the cooling medium. And oxidant gas outlet communication holes 30b for discharging the oxidant gas are arranged in the direction of arrow B.

  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 10 with a resin frame. . On the inlet side (upper end side) of the oxidant gas flow path 36, a buffer region 38a with which the inlet buffer portion 29c provided at the upper end edge of the surface 26cs of the resin frame member 26 abuts is provided in a substantially flat shape. It is done. A plurality of inlet connection paths 40a are connected to one end on the upper side of the buffer region 38a from the oxidant gas inlet communication hole 30a.

  On the outlet side (lower end side) of the oxidant gas flow path 36, a buffer region 38b is provided in contact with the outlet buffer portion 29d provided at the lower end edge of the surface 26cs of the resin frame member 26. A plurality of outlet connection paths 40b are connected to one end side of the buffer region 38b from the oxidant gas outlet communication hole 30b.

  As shown in FIG. 5, a fuel gas flow path 42 extends in the direction of arrow C on the surface 14 a of the first separator 14 facing the electrolyte membrane / electrode structure 10 with a resin frame.

  On the inlet side (upper end side) of the fuel gas flow path 42, a buffer region 44a that contacts an inlet buffer portion 29a provided at the upper end edge of the surface 26as of the resin frame member 26 is provided. A plurality of inlet connection passages 46a are connected to the end of the buffer region 44a on the fuel gas inlet communication hole 34a side, and the inlet connection passages 46a communicate with the plurality of supply hole portions 48a.

  On the outlet side (lower end side) of the fuel gas flow path 42, a buffer region 44b is provided in which an outlet buffer portion 29b provided at the lower end edge of the surface 26as of the resin frame member 26 contacts. A discharge hole portion 48b communicates with an end portion of the buffer region 44b on the fuel gas outlet communication hole 34b side via a plurality of outlet connection paths 46b.

  As shown in FIG. 1, on the surface 14b side of the first separator 14, a plurality of inlet connection passages 50a communicating the supply holes 48a and the fuel gas inlet communication holes 34a, and the discharge holes 48b and the fuel gas outlets. A plurality of outlet connection paths 50b communicating with the communication holes 34b are provided. A cooling medium flow path 52 that communicates the cooling medium inlet communication hole 32a and the cooling medium outlet communication hole 32b is provided in the direction of arrow C on the surface 14b.

  As shown in FIG. 2, in the gas diffusion layer 20 b, the overlapping region along the stacking direction faces the fuel gas channel 42. That is, the reaction gas permeation region 53 is provided around the outer periphery of the electrode catalyst layer 20a on the gas diffusion layer 20b side.

  As shown in FIGS. 1 and 2, the first seal member 54 is integrated with the 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 56 is integrated with the surfaces 16 a and 16 b of the second separator 16 around the outer peripheral end of the second separator 16.

  As shown in FIG. 2, the first seal member 54 has a flat seal having a certain thickness, and the flat seal is provided with a convex seal 54 a that contacts the second seal member 56. The second seal member 56 has a flat seal having a certain thickness, and the flat seal includes a convex seal 56a that contacts the resin frame member 26 constituting the electrolyte membrane / electrode structure 10 with a resin frame. Is provided.

  For the first seal member 54 and the second seal member 56, for example, EPDM, NBR, fluororubber, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene or acrylic rubber or the like, cushion material Or a packing material is used.

  Next, a method for producing the resin frame-attached electrolyte membrane / electrode structure 10 will be described below.

  First, as shown in FIG. 6, an electrolyte membrane / electrode structure 10a which is a step MEA is produced. Specifically, electrode catalyst layers 20 a and 22 a are applied to both surfaces 18 a and 18 b of the solid polymer electrolyte membrane 18. And the gas diffusion layer 20b is arrange | positioned at the surface 18a side of the solid polymer electrolyte membrane 18, ie, the electrode catalyst layer 20a. On the other hand, the gas diffusion layer 22b is disposed on the surface 18b of the solid polymer electrolyte membrane 18, that is, on the electrode catalyst layer 22a with the film member 24 interposed therebetween. These are integrally laminated and hot-pressed to produce the electrolyte membrane / electrode structure 10a.

  On the other hand, the resin frame member 26 is molded in advance by an injection molding machine (not shown). The resin frame member 26 is formed into a frame shape and is provided with a thin inner peripheral bulging portion 26a. At both end edges in the longitudinal direction of the resin frame member 26, a plurality of protrusions are formed on both surfaces, whereby inlet buffer portions 29a and 29c and outlet buffer portions 29b and 29d are provided.

  Next, in the electrolyte membrane / electrode structure 10a, an adhesive layer 27 is provided on the outer peripheral edge of the solid polymer electrolyte membrane 18 exposed from the outer periphery of the anode electrode 20 to the outside. The resin frame member 26 and the electrolyte membrane / electrode structure 10a are aligned.

  The resin frame member 26 has an inner peripheral bulging portion 26a disposed on the anode electrode 20 side, the adhesive layer 27 is heated and melted (hot melted), and a load (press or the like) is applied. For this reason, the inner peripheral bulging portion 26a and the solid polymer electrolyte membrane 18 are bonded.

  Further, a resin member 28aa for forming the resin impregnated portion 28a is prepared on the anode electrode 20 side, while a resin member 28bb for forming the resin impregnated portion 28b is prepared on the cathode electrode 22 side. . The resin members 28aa and 28bb have a frame shape (frame shape), and are made of the same material as the resin frame member 26, for example. The resin impregnated portion 28a may be used as necessary, and may be unnecessary.

  Therefore, the resin members 28aa and 28bb are heated in a state where the resin members 28aa and 28bb are arranged and a load is applied to the electrolyte membrane / electrode structure 10a and the resin frame member 26. As the heating method, laser welding, infrared welding, impulse welding, or the like is employed.

  Accordingly, the resin members 28aa and 28bb are heated and melted, and the resin member 28aa is impregnated across the gas diffusion layer 20b and the resin frame member 26 constituting the anode electrode 20. The resin member 28bb is impregnated across the gas diffusion layer 22b and the resin frame member 26 constituting the cathode electrode 22. Thereby, as shown in FIG. 2, the electrolyte membrane and electrode structure 10 with a resin frame is manufactured.

  The electrolyte membrane / electrode structure 10 with a resin frame is sandwiched between a first separator 14 and a second separator 16 to form a fuel cell 12. A predetermined number of fuel cells 12 are stacked to constitute a fuel cell stack, and a clamping load is applied between end plates (not shown).

  The operation of the fuel cell 12 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, and moves in the direction of arrow C to the cathode electrode 22 of the electrolyte membrane / electrode structure 10a. Supplied. On the other hand, the fuel gas is introduced into the fuel gas flow path 42 of the first separator 14 from the fuel gas inlet communication hole 34a through the supply hole 48a. The fuel gas moves in the direction of arrow C along the fuel gas flow path 42 and is supplied to the anode electrode 20 of the electrolyte membrane / electrode structure 10a.

  Therefore, in the electrolyte membrane / electrode structure 10a, the oxidant gas supplied to the cathode electrode 22 and the fuel gas supplied to the anode electrode 20 are consumed by an electrochemical reaction in the electrode catalyst layer to generate power. Is called.

  Next, the oxidant gas consumed by being supplied to the cathode 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 electrode 20 is discharged in the direction of arrow A along the fuel gas outlet communication hole 34b through the discharge hole 48b.

  The cooling medium supplied to the cooling medium inlet communication hole 32 a is introduced into the cooling medium flow path 52 between the first separator 14 and the second separator 16 and then flows in the direction of arrow C. The cooling medium is discharged from the cooling medium outlet communication hole 32b after the electrolyte membrane / electrode structure 10a is cooled.

  In this case, in the first embodiment, as shown in FIGS. 2 and 3, in the cathode electrode 22, the outer peripheral end 22ae of the electrode catalyst layer 22a is interposed between the solid polymer electrolyte membrane 18 and the gas diffusion layer 22b. A frame-shaped film member 24 having an overlapping portion 24a is provided.

  Therefore, the oxidant gas that has passed through the gas diffusion layer 22b from the cathode electrode 22 side does not come into contact with the solid polymer electrolyte membrane 18. Therefore, the reaction between the oxidant gas and the fuel gas is not induced at the end of the solid polymer electrolyte membrane 18, and the deterioration of the solid polymer electrolyte membrane 18 can be suppressed as much as possible. .

  Moreover, in the anode electrode 20, a reaction gas permeation region (including the fuel gas flow path 42) 53 is provided around the outer periphery of the electrode catalyst layer 20 a on the gas diffusion layer 20 b side. As a result, the oxidant gas that has permeated the solid polymer electrolyte membrane 18 does not stay at the end of the solid polymer electrolyte membrane 18, and the oxidant gas is transferred from the gas diffusion layer 20 b to the fuel gas channel 42. It can be smoothly and reliably discharged.

  For this reason, the end portion of the solid polymer electrolyte membrane 18 is formed of hydrogen peroxide generated by the reaction between the oxidant gas and the fuel gas, or a hydroxy radical (.OH) generated using the hydrogen peroxide as a precursor. It is possible to obtain an effect of effectively and reliably suppressing the deterioration by the deterioration promoting substance.

  FIG. 7 is a cross-sectional explanatory view of a polymer electrolyte fuel cell 62 in which an electrolyte membrane / electrode structure 60 with a resin frame according to the second embodiment of the present invention is incorporated. Note that the same components as those of the fuel cell 12 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Similarly, in the third and subsequent embodiments described below, detailed description thereof is omitted.

  The anode electrode 20 constituting the resin membrane-attached electrolyte membrane / electrode structure 60 includes an electrode catalyst layer (anode catalyst layer) 20c joined to one surface 18a of the solid polymer electrolyte membrane 18, and the electrode catalyst layer 20c. A gas diffusion layer (anode diffusion layer) 20d to be laminated is provided. The outer peripheral end 20de of the gas diffusion layer 20d protrudes outward (outward in the direction of arrow C) from the outer peripheral end 20ce of the electrode catalyst layer 20c, and the gas diffusion layer 20d is formed on the solid polymer electrolyte membrane 18. The outer dimension is set smaller than the outer dimension.

  The cathode electrode 22 is provided with an electrode catalyst layer (cathode catalyst layer) 22c bonded to the surface 18b of the solid polymer electrolyte membrane 18, and a gas diffusion layer (cathode diffusion layer) 22d laminated on the electrode catalyst layer 22c. . The outer peripheral end 22ce of the electrode catalyst layer 22c protrudes outward (outward in the direction of arrow C) from the outer peripheral end 20ce of the electrode catalyst layer 20c, and the outer peripheral end 22de of the gas diffusion layer 22d is a solid polymer. The outer dimension is set to be the same (or less than the same) as the outer dimension of the electrolyte membrane 18.

  In the cathode electrode 22, a frame-shaped film member 24 is provided between the solid polymer electrolyte membrane 18 and the gas diffusion layer 22d, having an outer peripheral end portion 22ce of the electrode catalyst layer 22c and an overlapping portion 24b. The overlapping portion 24b of the film member 24 overlaps the outer peripheral end 20ce of the electrode catalyst layer 20c constituting the anode electrode 20 in the thickness direction (arrow A direction). In the gas diffusion layer 20d, a reaction gas permeation region 53 is provided around the outer periphery of the electrode catalyst layer 20c.

  In the second embodiment configured as described above, the surface dimension of the electrode catalyst layer 20c of the anode electrode 20 is set smaller than the surface dimension of the electrode catalyst layer 22c of the cathode electrode 22, and this relationship is This is the opposite of the first embodiment. In addition, in 2nd Embodiment, the film member 24 and the reactive gas permeation | transmission area | region 53 are provided, and the effect similar to said 1st Embodiment is acquired.

  FIG. 8 shows a reactive gas impervious region 70 used in place of the film member 24. The reactive gas impermeable region 70 has an overlapping portion 70a with the outer peripheral end 22ae of the electrode catalyst layer 22a.

  The reactive gas impermeable region 70 can be configured, for example, by impregnating the gas diffusion layer 22b with a resin member and smoothing the entire surface. The reactive gas impervious region 70 can also be configured by pressing the outer peripheral edge of the gas diffusion layer 22b to make it dense and smoothing the entire surface.

  Thereby, the reaction gas impermeable region 70 has the same effect as the film member 24. The reactive gas impermeable region 70 is used in the fuel cell 12 according to the first embodiment, but may be used in the fuel cell 62 according to the second embodiment.

  FIG. 9 is a cross-sectional explanatory view of a polymer electrolyte fuel cell 82 in which an electrolyte membrane / electrode structure 80 with a resin frame according to a third embodiment of the present invention is incorporated. In addition, 3rd Embodiment is comprised similarly to the electrolyte membrane and electrode structure 10 with a resin frame which concerns on 1st Embodiment fundamentally.

  In the electrolyte membrane / electrode structure 80 with a resin frame, the outer peripheral end 20be of the gas diffusion layer 20b constituting the anode electrode 20 is more outward (outward in the direction of arrow C) than the outer peripheral end 20ae of the electrode catalyst layer 20a. While projecting, the gas diffusion layer 20 b is set to an outer dimension smaller than the outer dimension of the solid polymer electrolyte membrane 18.

  The outer peripheral end 22ae of the electrode catalyst layer 22a constituting the cathode electrode 22 is spaced inward (inward in the direction of arrow C) from the outer peripheral end 20ae of the electrode catalyst layer 20a, and the outer peripheral end of the gas diffusion layer 22b. 22be is set to the same outer dimension (or less than the same) as the outer dimension of the solid polymer electrolyte membrane 18. The surface dimension of the electrode catalyst layer 22 a of the cathode electrode 22 is set smaller than the surface dimension of the electrode catalyst layer 20 a of the anode electrode 20.

  The anode electrode 20 has a frame-like film member (reactive gas non-reactive) having an overlapping portion 24a and an outer peripheral end 20ae of the electrode catalyst layer 20a between the surface 18a of the solid polymer electrolyte membrane 18 and the gas diffusion layer 20b. A transmission region) 24 is provided. On the gas diffusion layer 22 b side, a reaction gas permeation region 53 that goes around the outer periphery of the electrode catalyst layer 22 a and faces the oxidant gas flow path 36 is provided.

  In this case, in the third embodiment, the anode electrode 20 has the overlapping portion 24a with the outer peripheral end 20ae of the electrode catalyst layer 20a between the surface 18a of the solid polymer electrolyte membrane 18 and the gas diffusion layer 20b. A frame-shaped film member 24 is provided.

  Therefore, the fuel gas that has passed through the gas diffusion layer 20b from the anode electrode 20 side does not come into contact with the solid polymer electrolyte membrane 18. Therefore, the reaction between the oxidant gas and the fuel gas is not induced at the end of the solid polymer electrolyte membrane 18, and the deterioration of the solid polymer electrolyte membrane 18 can be suppressed as much as possible. .

  Moreover, the cathode electrode 22 is provided with a reaction gas permeable region 53 on the gas diffusion layer 22b side. As a result, the fuel gas that has permeated the solid polymer electrolyte membrane 18 does not stay at the end of the solid polymer electrolyte membrane 18, and the fuel gas is smoothly transferred from the gas diffusion layer 22b to the oxidant gas flow path 36. And it can discharge reliably.

  FIG. 10 is a cross-sectional explanatory view of a polymer electrolyte fuel cell 92 in which an electrolyte membrane / electrode structure 90 with a resin frame according to the fourth embodiment of the present invention is incorporated. In addition, in 4th Embodiment, it is comprised similarly to the electrolyte membrane and electrode structure 60 with a resin frame which concern on 2nd Embodiment.

  In the electrolyte membrane / electrode structure 90 with a resin frame, the outer peripheral end 20de of the gas diffusion layer 20d constituting the anode electrode 20 is more outward (outward in the direction of arrow C) than the outer peripheral end 20ce of the electrode catalyst layer 20c. While projecting, the gas diffusion layer 20 d is set to an outer dimension smaller than the outer dimension of the solid polymer electrolyte membrane 18.

  The outer peripheral end 22ce of the electrode catalyst layer 22c constituting the cathode electrode 22 protrudes outward (outward in the direction of arrow C) from the outer peripheral end 20ce of the electrode catalyst layer 20c, and the outer peripheral end of the gas diffusion layer 22d. 22de is set to the same outer dimension (or less than the same) as the outer dimension of the solid polymer electrolyte membrane 18.

  In the anode electrode 20, a frame-shaped film member 24 is provided between the solid polymer electrolyte membrane 18 and the gas diffusion layer 20d, having an outer peripheral end portion 20ce of the electrode catalyst layer 20c and an overlapping portion 24b.

  In the fourth embodiment configured as described above, the surface dimension of the electrode catalyst layer 20c of the anode electrode 20 is set smaller than the surface dimension of the electrode catalyst layer 22c of the cathode electrode 22, and this relationship is This is the opposite of the third embodiment. In addition, in 4th Embodiment, the effect similar to said 3rd Embodiment is acquired.

DESCRIPTION OF SYMBOLS 10, 60, 80, 90 ... Electrolyte membrane / electrode structure with resin frame 10a ... Electrolyte membrane / electrode structure 12, 62, 82, 92 ... Fuel cell 14, 16 ... Separator 18 ... Solid polymer electrolyte membrane 20 ... Anode Electrode 20a, 20c, 22a, 22c ... Electrode catalyst layer 20b, 20d, 22b, 22d ... Gas diffusion layer 22 ... Cathode electrode 20ae, 20be, 20ce, 20de, 22ae, 22be, 22ce, 22de ... Outer edge 24 ... Film member 24a, 24b, 70a ... overlapping part 26 ... resin-made frame member 26a ... inner peripheral bulging part 28a, 28b ... resin impregnated part 29a, 29c ... inlet buffer part 29b, 29d ... outlet buffer part 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 42 ... fuel gas flow path 52 ... cooling medium flow path 53 ... reactive gas permeation area 54, 56 ... seal member 70 ... reactive gas impervious area

Claims (2)

An anode electrode having an anode catalyst layer and an anode diffusion layer having a larger surface dimension than the anode catalyst layer is provided on one surface of the solid polymer electrolyte membrane, and the other surface of the solid polymer electrolyte membrane is A cathode electrode having a cathode catalyst layer and a cathode diffusion layer having a surface dimension larger than that of the cathode catalyst layer, and a fuel in which the surface dimension of the anode catalyst layer and the surface dimension of the cathode catalyst layer are set to different dimensions An electrolyte membrane / electrode structure for a battery,
Between the solid polymer electrolyte membrane and the cathode diffusion layer or the anode diffusion layer, there is a frame-shaped reaction gas impervious region having an overlapping portion with an outer peripheral end of the cathode catalyst layer or the anode catalyst layer. Is provided,
An electrolyte membrane / electrode structure for a fuel cell, characterized in that a reaction gas permeation region is provided around the outer periphery of the catalyst layer of the counter electrode on the diffusion layer side of the counter electrode.   2. The fuel cell electrolyte membrane / electrode structure according to claim 1, wherein the reaction gas impermeable region has an inner peripheral side end portion of the frame shape that is thicker than an outer peripheral end portion of the anode catalyst layer or the cathode catalyst layer. An electrolyte membrane / electrode structure for a fuel cell, characterized by having overlapping portions in the vertical direction.

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