JP6104096B2 - Fuel cell - Google Patents

Description

  In the present invention, an electrolyte membrane / electrode structure in which electrodes having an electrode catalyst layer and a gas diffusion layer are provided on both sides of a solid polymer electrolyte membrane is sandwiched between a pair of metal separators whose plate surfaces are formed in a corrugated shape. The present invention relates to a fuel cell.

  For example, in a polymer electrolyte fuel cell, an electrolyte membrane / electrode structure (MEA) provided with an anode electrode and a cathode electrode on both sides of a solid polymer electrolyte membrane made of a polymer ion exchange membrane is formed by a pair of separators. The sandwiched power generation cell is configured. A fuel cell is usually used as an in-vehicle fuel cell system by stacking a plurality of power generation cells to form a fuel cell stack and incorporating it into a fuel cell vehicle in addition to a stationary one.

  In the above fuel cell, a metal separator formed into a wave shape is used. In the plane of the metal separator, a fuel gas flow path (hereinafter also referred to as a reaction gas flow path) for flowing a fuel gas to the anode electrode, and an oxidant gas flow path (hereinafter referred to as a reactive gas flow path) for flowing an oxidant gas to the cathode electrode. A reaction gas channel). Further, a cooling medium flow path for flowing the cooling medium is provided along the surface direction of the metal separator for each power generation cell or for each of the plurality of power generation cells.

  In this type of fuel cell, it is necessary to moisturize the electrolyte membrane in order to ensure good ion conductivity. For this reason, a method is employed in which an oxidizing gas (for example, air) or a fuel gas (for example, hydrogen gas), which is a reactive gas, is humidified and supplied to the fuel cell.

  At this time, moisture for humidification may be liquefied without being absorbed by the electrolyte membrane and stay in the reaction gas flow path. On the other hand, in the fuel cell, generated water is generated at the cathode electrode by a power generation reaction, and the generated water is back-diffused through the electrolyte membrane in the anode electrode. For this reason, moisture may condense and stay in the reaction gas channel. Therefore, for example, when a high potential or a potential gradient occurs at the end of the cathode electrode or the end of the anode electrode, elution of the metal from the metal separator is caused by the retained water, and the eluted metal may be taken into the electrolyte membrane. is there. As a result, the electrolyte membrane has a problem that the deterioration due to metal ions becomes significant.

  Thus, for example, a metal separator for a fuel cell disclosed in Patent Document 1 is known. This metal separator for a fuel cell has an acid-resistant metal film having a film thickness of 5 nm or more and less than 100 nm made of any one non-noble metal selected from Zr, Nb, and Ta on the surface of a metal substrate. Yes. The metal separator for a fuel cell includes one or more kinds of noble metals selected from Au and Pt and one or more kinds of non-noble metals selected from Zr, Nb, and Ta on the acid-resistant metal film. It has a conductive alloy film containing 5 to 65 atomic% of noble metal and having a thickness of 2 nm or more.

  The acid-resistant metal film is formed on the metal substrate by applying a voltage of −50 V or less while heating the metal substrate to 50 ° C. or higher in the PVD method.

Japanese Patent No. 4516628

  However, in said patent document 1, the metal base material is surface-treated and the metal separator is comprised. For this reason, the manufacturing cost of the metal separator itself is considerably increased, which is not economical.

  The present invention solves this type of problem and prevents elution of metal ions from the metal separator and suppresses deterioration of the solid polymer electrolyte membrane as much as possible with a simple and economical configuration. An object of the present invention is to provide a fuel cell capable of satisfying the requirements.

  In the present invention, an electrolyte membrane / electrode structure in which electrodes having an electrode catalyst layer and a gas diffusion layer are provided on both sides of a solid polymer electrolyte membrane is sandwiched between a pair of metal separators whose plate surfaces are formed in a corrugated shape. In addition, the metal separator relates to a fuel cell in which a reaction gas flow path for supplying a reaction gas along the electrode surface is formed.

In this fuel cell, a resin frame member is integrally provided on the outer periphery of the metal separator. On the metal separator and the resin frame member, convex portions in contact with the electrolyte membrane / electrode structure and concave portions separated from the electrolyte membrane / electrode structure are alternately formed. The reaction gas channel is provided by forming a plurality of reaction gas channel grooves along the recess. The reaction gas flow channel groove has an end reaction gas flow channel disposed outward in the width direction intersecting the reaction gas flow direction of the reaction gas flow channel, and the end reaction gas flow channel is While facing the outer peripheral end of the electrode catalyst layer, it is provided on the resin frame member.

  Further, in this fuel cell, the reaction gas channel groove distributes the reaction gas in the power generation region, and the end reaction gas flow arranged outside in the width direction intersecting the reaction gas flow direction of the reaction gas channel. The end reaction gas channel groove is provided in the resin frame member.

  Further, in this fuel cell, the resin frame member is provided with a reaction gas communication hole for allowing the reaction gas to flow in the stacking direction of the electrolyte membrane / electrode structure, and a buffer for connecting the reaction gas flow path and the reaction gas communication hole. The part is preferably provided integrally.

  Furthermore, in this fuel cell, it is preferable that each electrode catalyst layer has a different surface area, and a portion where only the electrode catalyst layer of one electrode exists is provided on the outer periphery of the solid polymer electrolyte membrane. .

  Moreover, in this fuel cell, it is preferable that the front end or the rear end in the gas flow direction of the reaction gas channel is located outside the electrode catalyst layer.

  Furthermore, in this fuel cell, it is preferable that the outer peripheral end portion of the metal separator extends to the outer peripheral end portion of the resin frame member.

  In the present invention, the end reaction gas channel groove is provided in the resin frame member. For this reason, the metal separator itself is not particularly arranged to face the outer peripheral end of the electrode catalyst layer where a high potential or potential gradient is likely to occur, and metal ions are eluted from the outer end of the metal separator. Can be reliably suppressed. Accordingly, it is possible to suppress deterioration of the outer peripheral portion of the electrolyte membrane / electrode structure.

  Thereby, with a simple and economical configuration, elution of metal ions from the metal separator can be prevented, and deterioration of the solid polymer electrolyte membrane can be suppressed as much as possible.

It is a principal part disassembled perspective explanatory drawing of the fuel cell which concerns on the 1st Embodiment of this invention. FIG. 2 is a sectional view of the fuel cell taken along line II-II in FIG. 1. It is front explanatory drawing of the 1st metal separator which comprises the said fuel cell. It is front explanatory drawing of the 2nd metal separator which comprises the said fuel cell. It is principal part cross-sectional explanatory drawing of the fuel cell which concerns on the 2nd Embodiment of this invention. It is principal part cross-sectional explanatory drawing of the fuel cell which concerns on the 3rd Embodiment of this invention. It is a principal part disassembled perspective explanatory drawing of the fuel cell which concerns on the 4th Embodiment of this invention. FIG. 8 is a sectional view of the fuel cell taken along line VIII-VIII in FIG. 7. It is front explanatory drawing of the 1st metal separator which comprises the said fuel cell. It is front explanatory drawing of the 2nd metal separator which comprises the said fuel cell. It is principal part sectional explanatory drawing of the fuel cell which concerns on the 5th Embodiment of this invention. It is principal part sectional explanatory drawing of the fuel cell which concerns on the 6th Embodiment of this invention. It is a principal part disassembled perspective explanatory drawing of the fuel cell which concerns on the 7th Embodiment of this invention. It is XIV-XIV sectional view explanatory drawing in FIG. 13 of the said fuel cell. It is principal part cross-sectional explanatory drawing of the fuel cell which concerns on the 8th Embodiment of this invention.

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

  The fuel cell 10 includes an electrolyte membrane / electrode structure 12, and a first metal separator 14 and a second metal separator 16 that sandwich the electrolyte membrane / electrode structure 12. The first metal separator 14 and the second metal separator 16 are, for example, pressed into a corrugated shape from a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, or a metal plate whose surface has been subjected to anticorrosion treatment. Thus, it has a concave-convex shape in cross section.

  The electrolyte membrane / electrode structure 12 includes a solid polymer electrolyte membrane 18, and a cathode electrode 20 and an anode electrode 22 that sandwich the solid polymer electrolyte membrane 18. As shown in FIG. 2, the cathode electrode 20 and the anode electrode 22 include a cathode side gas diffusion layer 20a and an anode side gas diffusion layer 22a made of carbon paper or the like, and a cathode electrode catalyst layer 20b and an anode electrode catalyst layer 22b. . In the cathode electrode catalyst layer 20b and the anode electrode catalyst layer 22b, porous carbon particles having platinum and a platinum alloy supported thereon are uniformly applied to the surfaces of the cathode side gas diffusion layer 20a and the anode side gas diffusion layer 22a. . In addition, the solid polymer electrolyte membrane 18 may be directly manufactured by coating, spraying, transfer, or the like, and various manufacturing methods can be employed.

  The cathode electrode catalyst layer 20b has a smaller planar dimension over the entire circumference than the anode electrode catalyst layer 22b. The cathode side gas diffusion layer 20a has a larger planar dimension than the anode side gas diffusion layer 22a.

  The cathode electrode catalyst layer 20b may have a larger or the same planar dimension as the anode electrode catalyst layer 22b. The cathode-side gas diffusion layer 20a may have the same planar dimension as the anode-side gas diffusion layer 22a, or the cathode-side gas diffusion layer 20a has a smaller planar dimension than the anode-side gas diffusion layer 22a. You may have. The same applies to the following second and subsequent embodiments.

  As shown in FIG. 1, one end edge of the fuel cell 10 in the direction of the arrow B (the horizontal direction in FIG. 1) is specifically in the direction of the arrow B of the resin frame member 32 described later. An oxidant gas inlet communication hole 24a, a cooling medium inlet communication hole 26a, and a fuel gas outlet communication hole 28b are provided at one end edge. The oxidant gas inlet communication hole 24a supplies an oxidant gas, for example, an oxygen-containing gas, the cooling medium inlet communication hole 26a supplies a cooling medium, and the fuel gas outlet communication hole 28b has a fuel gas, for example, hydrogen. The contained gas is discharged. The oxidant gas inlet communication hole 24a, the cooling medium inlet communication hole 26a, and the fuel gas outlet communication hole 28b are provided to communicate with each other in the direction of arrow A, which is the stacking direction, and are arranged in the direction of arrow C (vertical direction). .

  Specifically, the other end edge of the fuel cell 10 in the arrow B direction, specifically, the other end edge of the resin frame member 32 in the arrow B direction, a fuel gas inlet communication hole 28a for supplying fuel gas, A cooling medium outlet communication hole 26b for discharging the cooling medium and an oxidant gas outlet communication hole 24b for discharging the oxidant gas are provided. The fuel gas inlet communication hole 28a, the coolant outlet communication hole 26b, and the oxidant gas outlet communication hole 24b communicate with each other in the direction of arrow A and are arranged in the direction of arrow C.

  As shown in FIG. 3, the first metal separator 14 includes a metal plate 30 and an electrically insulating resin frame member 32 integrally formed on the outer periphery of the metal plate 30. The joint between the metal plate 30 and the resin frame member 32 is provided on a convex portion that protrudes toward the electrolyte membrane / electrode structure 12 of the first metal separator 14.

  The resin frame member 32 is made of a material having corrosion resistance, such as polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyimide (PI), polyethersulfone (PES), or liquid crystal polymer (LCP). The resin frame member 32 has substantially the same thickness as the first metal separator 14. In addition, as for the 1st metal separator 14, three sides including the communication hole of a base and both ends may be comprised with the resin frame. The same applies to the second metal separator 16 described below.

  A fuel gas flow path (reactive gas flow path) 34 communicating with the fuel gas inlet communication hole 28a and the fuel gas outlet communication hole 28b is formed on the surface 14a of the first metal separator 14 facing the electrolyte membrane / electrode structure 12. Is done. The fuel gas flow path 34 has a plurality of fuel gas streams formed along each recess 36b by alternately forming protrusions 36a and recesses 36b extending in the direction of arrow B in the direction of arrow C. It has a road groove 34a. The convex portion 36 a is in contact with the electrolyte membrane / electrode structure 12, while the concave portion 36 b is separated from the electrolyte membrane / electrode structure 12.

  As shown in FIGS. 2 and 3, the fuel gas flow channel groove 34 a constituting the fuel gas flow channel 34 has a width direction (arrow C) that intersects the fuel gas flow direction (arrow B direction) of the fuel gas flow channel 34. Direction) and has an end fuel gas flow channel groove 34ae disposed outward and facing the outer peripheral end 22be of the anode electrode catalyst layer 22b. The end part fuel gas flow path groove 34ae should just be provided in the edge part of at least one width direction, and may be provided two or more. Further, the end fuel gas channel groove 34 ae may be formed by carving a groove in the thick resin frame member 32.

  The end fuel gas channel groove 34 ae is provided in the resin frame member 32. As shown in FIG. 3, at both ends in the arrow B direction of the fuel gas flow path 34, regions including the range of the distance L <b> 1 are configured by the resin frame member 32. That is, the distance L <b> 1 is set so that the inner peripheral end position of the resin frame member 32 is the outer peripheral end position of the power generation region of the electrolyte membrane / electrode structure 12.

  In the first metal separator 14, a plurality of supply holes 35a are formed in the vicinity of the fuel gas inlet communication hole 28a, and a plurality of discharge holes 35b are formed in the vicinity of the fuel gas outlet communication hole 28b. The supply hole 35a communicates the fuel gas inlet communication hole 28a and the fuel gas flow path 34, while the discharge hole 35b communicates the fuel gas outlet communication hole 28b and the fuel gas flow path 34.

  As shown in FIG. 4, the second metal separator 16 includes a metal plate 40 and an electrically insulating resin frame member 42 integrally formed on the outer periphery of the metal plate 40. A joint between the metal plate 30 and the resin frame member 32 is provided on the convex portion of the first metal separator 14 that protrudes toward the electrolyte membrane / electrode structure 12 side. The joint between the metal plate 40 and the resin frame member 42 is provided on a convex portion that protrudes toward the electrolyte membrane / electrode structure 12 side of the second metal separator 16.

  For the resin frame member 42, a material having corrosion resistance, for example, polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyimide (PI), polyethersulfone (PES), or liquid crystal polymer (LCP) is used. The resin frame member 42 has substantially the same thickness as the second metal separator 16.

  On the surface 16a of the second metal separator 16 facing the electrolyte membrane / electrode structure 12, an oxidant gas flow path (reactive gas flow path) communicating with the oxidant gas inlet communication hole 24a and the oxidant gas outlet communication hole 24b. 44 is formed. The oxidant gas flow path 44 has a plurality of oxidants formed along the respective recesses 45b by alternately forming the protrusions 45a and the recesses 45b extending in the arrow B direction in the arrow C direction. A gas channel groove 44a is provided. The convex portion 45 a is in contact with the electrolyte membrane / electrode structure 12, while the concave portion 45 b is separated from the electrolyte membrane / electrode structure 12.

  As shown in FIGS. 2 and 4, the oxidant gas flow channel groove 44 a constituting the oxidant gas flow channel 44 has a width that intersects the oxidant gas flow direction (arrow B direction) of the oxidant gas flow channel 44. It has an end oxidant gas flow channel groove 44ae disposed outward in the direction (arrow C direction) and facing the outer peripheral end 20be of the cathode electrode catalyst layer 20b. The end oxidant gas flow path grooves 44ae may be provided at least at one end in the width direction, and two or more end oxidant gas flow path grooves 44ae may be provided. Further, the end oxidant gas flow path groove 44 ae may be formed by engraving the thick resin frame member 42.

  The end oxidant gas passage groove 44 ae is provided in the resin frame member 42. As shown in FIG. 4, at both ends in the arrow B direction of the oxidant gas flow path 44, regions including the range of the distance L <b> 2 are configured by the resin frame member 42. That is, the distance L <b> 2 is set so that the inner peripheral end position of the resin frame member 42 is the outer peripheral end position of the power generation region of the electrolyte membrane / electrode structure 12. The resin frame members 32 and 42 may be provided only on either the first metal separator 14 or the second metal separator 16.

  As shown in FIG. 1, between the surface 14b of the first metal separator 14 and the surface 16b of the second metal separator 16, a cooling medium flow communicating with the cooling medium inlet communication hole 26a and the cooling medium outlet communication hole 26b. A path 46 is formed.

  As shown in FIGS. 1 and 2, the first seal member 48 is integrated with the surfaces 14 a and 14 b of the first metal separator 14 around the outer peripheral end of the first metal separator 14. The second seal member 50 is integrated with the surfaces 16 a and 16 b of the second metal separator 16 around the outer peripheral end of the second metal separator 16.

  As shown in FIG. 2, the first seal member 48 includes a first convex seal 48 a that abuts on the leading edge of the solid polymer electrolyte membrane 18, and a second convex seal 48 b that abuts the second seal member 50. Have The second seal member 50 constitutes a flat seal having a flat seal surface. Instead of the second convex seal 48b, the second seal member 50 may be provided with a second convex seal (not shown).

  The first seal member 48 and the second seal member 50 include, for example, EPDM, NBR, fluorine rubber, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene or acrylic rubber, and cushioning materials. Alternatively, an elastic seal member such as a packing material is used.

  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 24a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 28a. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the cooling medium inlet communication hole 26a.

  Therefore, the oxidant gas is introduced into the oxidant gas flow path 44 of the second metal separator 16 from the oxidant gas inlet communication hole 24a, moves in the arrow B direction, and the cathode electrode 20 of the electrolyte membrane / electrode structure 12. To be supplied. On the other hand, the fuel gas is introduced into the fuel gas flow path 34 of the first metal separator 14 from the fuel gas inlet communication hole 28a through the supply hole portion 35a. The fuel gas moves in the direction of arrow B along the fuel gas flow path 34 and is supplied to the anode electrode 22 of the electrolyte membrane / electrode structure 12.

  Accordingly, in each electrolyte membrane / electrode structure 12, the oxidant gas supplied to the cathode electrode 20 and the fuel gas supplied to the anode electrode 22 are electrically supplied in the cathode electrode catalyst layer 20b and the anode electrode catalyst layer 22b. 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 24b. Similarly, the fuel gas consumed by being supplied to the anode electrode 22 passes through the discharge hole portion 35b and is discharged in the direction of arrow A along the fuel gas outlet communication hole 28b.

  The cooling medium supplied to the cooling medium inlet communication hole 26 a is introduced into the cooling medium flow path 46 between the first metal separator 14 and the second metal separator 16 and then flows in the direction of arrow B. The cooling medium is discharged from the cooling medium outlet communication hole 26b after the electrolyte membrane / electrode structure 12 is cooled.

  In this case, in the first embodiment, as shown in FIGS. 2 and 4, the second metal separator 16 is provided with an oxidant gas flow path 44 and an oxidant gas constituting the oxidant gas flow path 44. The channel groove 44a has an end oxidant gas channel groove 44ae facing the outer peripheral end 20be of the cathode electrode catalyst layer 20b. The end oxidant gas flow channel 44 ae is provided in the resin frame member 42.

  On the other hand, the cathode electrode catalyst layer 20b has a smaller planar dimension than the anode electrode catalyst layer 22b, and the outer peripheral end portion 20be of the cathode electrode catalyst layer 20b is larger than the outer peripheral end portion 22be of the anode electrode catalyst layer 22b. Is also spaced inward by a distance S. For this reason, a high potential or a potential gradient is likely to occur in the vicinity of the half electrode region (distance S) where the anode electrode catalyst layer 22b exists only on one surface of the solid polymer electrolyte membrane 18.

  At that time, the first metal separator 14 is provided with a resin frame member 32 over a region where only the anode electrode catalyst layer 22b exists. Thereby, the elution of metal ions can be prevented from the outer end portion of the first metal separator 14 by a particularly high potential or potential gradient. In addition, since the end fuel gas flow channel groove 34ae faces the vicinity of the half electrode region (range of the distance S) where the anode electrode catalyst layer 22b exists, moisture does not stay in the outer peripheral end portion 22be.

  In addition, the first metal separator 14 can be plated with, for example, gold or carbon, inward of the resin frame member 32, and can also be provided with a corrosion-resistant film having conductivity.

  Therefore, it is possible to obtain an effect that the elution of the metal ions from the first metal separator 14 can be prevented and the deterioration of the solid polymer electrolyte membrane 18 can be suppressed as much as possible with a simple and economical configuration.

  The second metal separator 16 is provided with an oxidant gas flow path 44, and an oxidant gas flow path groove 44a constituting the oxidant gas flow path 44 is formed at the outer peripheral end 22be of the anode electrode catalyst layer 22b. Opposite end oxidant gas channel grooves 44ae are provided. The end oxidant gas flow channel 44 ae is provided in the resin frame member 42. Thereby, the second metal separator 16 has the same effect as the first metal separator 14 described above.

  FIG. 5 is an explanatory cross-sectional view of a main part of a fuel cell 60 according to the second embodiment of the present invention. The same components as those of the fuel cell 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Similarly, in the third and subsequent embodiments described below, detailed description thereof is omitted.

  The fuel cell 60 includes an electrolyte membrane / electrode structure 12, and a first metal separator 62 and a second metal separator 64 that sandwich the electrolyte membrane / electrode structure 12. The first metal separator 62 includes a metal plate 66 and a resin frame member 68 integrally formed on the outer periphery of the metal plate 66. The resin frame member 68 is configured to be thicker than the metal plate 66 in order to maintain a desired resin strength. At the inner peripheral end portion of the resin frame member 68, a superposition site 70 that overlaps and is integrated with the outer peripheral end portion of the metal plate 66 is provided.

  The second metal separator 64 includes a metal plate 72 and a resin frame member 74 integrally formed on the outer periphery of the metal plate 72. The resin frame member 74 is configured to be thicker than the metal plate 72 in order to maintain a desired resin strength. An overlapping portion 76 that overlaps and is integrated with the outer peripheral end of the metal plate 72 is provided at the inner peripheral end of the resin frame member 74. In the first embodiment and the third and subsequent embodiments, the resin frame member can be configured to be thicker than the metal plate.

  In the second embodiment configured as described above, the end fuel gas flow path groove 34ae is formed in the resin frame member 68, and the end oxidant gas flow path groove 44ae is formed in the resin frame member 74. Is formed. For this reason, the effect similar to said 1st Embodiment is acquired.

  FIG. 6 is an explanatory cross-sectional view of a main part of a fuel cell 80 according to the third embodiment of the present invention.

  The fuel cell 80 includes an electrolyte membrane / electrode structure 12 and a first metal separator 82 and a second metal separator 84 that sandwich the electrolyte membrane / electrode structure 12. The first metal separator 82 includes a metal plate 86 and a resin frame member 88 integrally formed on the outer periphery of the metal plate 86. An embedded portion 90 is provided at the inner peripheral end of the resin frame member 88 so as to sandwich the outer peripheral end of the metal plate 86 that is bent toward the electrolyte membrane / electrode structure 12 side.

  The second metal separator 84 includes a metal plate 92 and a resin frame member 94 integrally formed on the outer periphery of the metal plate 92. An embedded portion 96 is provided at the inner peripheral end portion of the resin frame member 94 so as to sandwich the outer peripheral end portion of the metal plate 92 that is bent toward the electrolyte membrane / electrode structure 12 side.

  In the third embodiment configured as described above, the end fuel gas flow path groove 34ae is formed in the resin frame member 88, and the end oxidant gas flow path groove 44ae is formed in the resin frame member 94. Is formed. Therefore, the same effects as those of the first and second embodiments can be obtained.

  FIG. 7 is an exploded perspective view of a main part of a fuel cell 100 according to the fourth embodiment of the present invention.

  The fuel cell 100 includes an electrolyte membrane / electrode structure 102 and a first metal separator 104 and a second metal separator 106 that sandwich the electrolyte membrane / electrode structure 102. As shown in FIGS. 7 and 8, the electrolyte membrane / electrode structure 102 includes a solid polymer electrolyte membrane 108, and a cathode electrode 20 and an anode electrode 22 that sandwich the solid polymer electrolyte membrane 108.

  The solid polymer electrolyte membrane 108 is set to have a larger plane size than the cathode electrode 20 and the anode electrode 22, and the outer peripheral edge protrudes outward from the outer peripheral ends of the cathode electrode 20 and the anode electrode 22.

  As shown in FIG. 9, the first metal separator 104 includes a metal plate 110 and a resin frame member 112 integrally formed on the outer periphery of the metal plate 110. An oxidant gas flow path 44 is formed on the surface 104 a of the first metal separator 104 facing the electrolyte membrane / electrode structure 102, and an end constituting the oxidant gas flow path 44 is formed on the resin frame member 112. A partial oxidant gas flow channel 44ae is provided.

  The resin frame member 112 is provided with an inlet buffer portion 114 having a plurality of embosses 114 a on the inlet side of the oxidant gas flow path 44, and an outlet having a plurality of embossments 116 a on the outlet side of the oxidant gas flow path 44. A buffer unit 116 is provided.

  As shown in FIG. 10, the second metal separator 106 includes a metal plate 118 and a resin frame member 120 integrally formed on the outer periphery of the metal plate 118. A surface 106a of the second metal separator 106 facing the electrolyte membrane / electrode structure 102 is formed with a fuel gas flow path 34 that connects the fuel gas inlet communication hole 28a and the fuel gas outlet communication hole 28b, and a resin frame. The member 120 is provided with an end fuel gas flow channel groove 34 ae constituting the fuel gas flow channel 34.

  The resin frame member 120 is provided with an inlet buffer part 122 having a plurality of embosses 122a on the inlet side of the fuel gas flow path 34, and an outlet buffer part having a plurality of embosses 124a on the outlet side of the fuel gas flow path 34. 124 is provided. As shown in FIG. 7, a cooling medium flow path 46 is formed between the surface 104b of the first metal separator 104 and the surface 106b of the second metal separator 106 adjacent to each other.

  A first seal member 126 is integrally formed on the surfaces 104 a and 104 b of the first metal separator 104 around the outer peripheral end of the first metal separator 104. A second seal member 128 is integrally formed on the surfaces 106 a and 106 b of the second metal separator 106 around the outer peripheral end of the second metal separator 106.

  As shown in FIG. 8, the first seal member 126 and the second seal member 128 have convex seals 126 a and 128 a that protrude toward the solid polymer electrolyte membrane 108 and sandwich the solid polymer electrolyte membrane 108. In addition, a resin frame member is provided on the outer peripheral portion of the electrolyte membrane / electrode structure 102, the outer peripheral end portion of the resin frame member is extended to the outer peripheral portion of the solid polymer electrolyte membrane 108, and a convex portion is formed on the outer peripheral end portion. The seals 126a and 128a may be brought into contact with each other. The same applies to the fifth and sixth embodiments described below.

  The fuel cell 100 configured as described above operates in the same manner as the fuel cell 10 according to the first embodiment. At that time, in the fourth embodiment, as shown in FIGS. 8 and 9, the first metal separator 104 is provided with the oxidant gas flow path 44 and the oxidant gas constituting the oxidant gas flow path 44. The channel groove 44a has an end oxidant gas channel groove 44ae facing the outer peripheral end 20be of the cathode electrode catalyst layer 20b. The end oxidant gas flow channel 44 ae is provided in the resin frame member 112.

  On the other hand, as shown in FIGS. 8 and 10, the second metal separator 106 is provided with a fuel gas flow path 34, and the fuel gas flow path groove 34a constituting the fuel gas flow path 34 has a cathode electrode catalyst layer 20b. The end fuel gas flow channel groove 34ae is opposed to the outer peripheral end portion 20be. The end fuel gas channel groove 34 ae is provided in the resin frame member 120.

  Therefore, the first metal separator 104 and the second metal separator 106 are provided with resin frame members 112 and 120 over a region where only the anode electrode catalyst layer 22b exists (a region where a high potential or a potential gradient is likely to be generated). It has been. Therefore, elution of metal ions from the first metal separator 104 and the second metal separator 106 can be prevented with a simple and economical configuration, and deterioration of the solid polymer electrolyte membrane 18 can be suppressed as much as possible. The same effects as those in the first to third embodiments can be obtained.

  FIG. 11 is an explanatory cross-sectional view of a main part of a fuel cell 140 according to the fifth embodiment of the present invention. Note that the same components as those of the fuel cell 100 according to the fourth embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Similarly, in the sixth embodiment described below, detailed description thereof is omitted.

  The fuel cell 140 includes an electrolyte membrane / electrode structure 102, and a first metal separator 142 and a second metal separator 144 that sandwich the electrolyte membrane / electrode structure 102. The first metal separator 142 includes a metal plate 146 and a resin frame member 148 integrally formed on the outer periphery of the metal plate 146. The resin frame member 148 is configured to be thicker than the metal plate 146 in order to maintain a desired resin strength. A polymerization site 150 integrated with the outer peripheral end of the metal plate 146 is provided at the inner peripheral end of the resin frame member 148.

  The second metal separator 144 includes a metal plate 152 and a resin frame member 154 integrally formed on the outer periphery of the metal plate 152. The resin frame member 154 is configured to be thicker than the metal plate 152 in order to maintain a desired resin strength. A polymerization site 156 that overlaps and is integrated with the outer peripheral end of the metal plate 152 is provided at the inner peripheral end of the resin frame member 154.

  In the fifth embodiment configured as described above, the end oxidant gas passage groove 44ae is formed in the resin frame member 148, and the end fuel gas passage groove 34ae is formed in the resin frame member 154. Yes. For this reason, the effect similar to said 4th Embodiment is acquired.

  FIG. 12 is an explanatory cross-sectional view of a main part of a fuel cell 160 according to the sixth embodiment of the present invention.

  The fuel cell 160 includes an electrolyte membrane / electrode structure 102, and a first metal separator 162 and a second metal separator 164 that sandwich the electrolyte membrane / electrode structure 102. The first metal separator 162 includes a metal plate 166 and a resin frame member 168 integrally formed on the outer periphery of the metal plate 166. An embedded portion 170 is provided at the inner peripheral end portion of the resin frame member 168 so as to sandwich the outer peripheral end portion of the metal plate 166 bent toward the electrolyte membrane / electrode structure 102 side.

  The second metal separator 164 includes a metal plate 172 and a resin frame member 174 integrally formed on the outer periphery of the metal plate 172. An embedded portion 176 is provided at the inner peripheral end portion of the resin frame member 174 so as to sandwich the outer peripheral end portion of the metal plate 172 that is bent toward the electrolyte membrane / electrode structure 102 side.

  In the sixth embodiment configured as described above, the end oxidant gas passage groove 44 ae is formed in the resin frame member 168, and the end fuel gas passage groove 34 ae is formed in the resin frame member 174. Yes. For this reason, the effect similar to said 4th and 5th embodiment is acquired.

  FIG. 13 is an exploded perspective view of the main part of a fuel cell 180 according to the seventh embodiment of the present invention. The same components as those of the fuel cell 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The fuel cell 180 includes an electrolyte membrane / electrode structure 12, and a first metal separator 182 and a second metal separator 184 that sandwich the electrolyte membrane / electrode structure 12. As shown in FIG. 14, the first metal separator 182 includes a metal plate 186. A resin frame member 188a is integrally formed on the surface 186a of the metal plate 186 facing the electrolyte membrane / electrode structure 12 so as to cover the outer peripheral edge of the surface 186a. The resin frame member 188a is provided with an end fuel gas passage groove 34ae.

  A resin frame member 188b is integrally formed on the surface 186b of the metal plate 186 on the cooling medium flow path 46 side so as to cover the outer peripheral edge of the surface 186b. The resin frame member 188b may not be provided. It is preferable to provide a coating 190 made of a gold coating or a conductive corrosion-resistant coating on the projection-side surfaces 186ae and 186be of the metal plate 186, if necessary.

  The second metal separator 184 includes a metal plate 192. A resin frame member 194a is integrally formed on the surface 192a of the metal plate 192 facing the electrolyte membrane / electrode structure 12 so as to cover the outer peripheral edge of the surface 192a. The resin frame member 194a is provided with an end oxidizing gas channel groove 44ae.

  A resin frame member 194b is integrally formed on the surface 192b of the metal plate 192 on the cooling medium flow path 46 side so as to cover the outer peripheral edge of the surface 192b. The resin frame member 194b may not be provided. It is preferable to provide a coating 190 made of a gold coating or a conductive corrosion-resistant coating on the surfaces 192ae and 192be on the convex portion side of the metal plate 192 as necessary.

  In the seventh embodiment configured as described above, in the first metal separator 182, resin frame members 188 a and 188 b are integrally formed on both surfaces 186 a and 186 b extending to the separator outer periphery of the metal plate 186. For this reason, the effect that the intensity | strength as the 1st metal separator 182 whole improves further is acquired. The second metal separator 184 also has the same effect as the first metal separator 182 described above.

  FIG. 15 is an explanatory cross-sectional view of a relevant part of a fuel cell 200 according to the eighth embodiment of the present invention. Note that the same components as those of the fuel cell 180 according to the seventh embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The fuel cell 200 includes an electrolyte membrane / electrode structure 12, and a first metal separator 202 and a second metal separator 204 that sandwich the electrolyte membrane / electrode structure 12. The first metal separator 202 includes a metal plate 206. The resin material constituting the resin frame members 208a and 208b is integrally formed in advance on the surface 206a facing the electrolyte membrane / electrode structure 12 of the metal plate 206 and the opposite surface 206b. Thereafter, the resin frame members 208a and 208b are formed by removing the resin material from the convex-side surfaces 206ae and 206be of the metal plate 206. A coating 190 having conductivity and corrosion resistance is provided on the surfaces 206ae and 206be as necessary. The resin frame member 208a is provided with an end fuel gas passage groove 34ae.

  The second metal separator 204 includes a metal plate 210. Resin materials constituting the resin frame members 212a and 212b are integrally formed in advance on the surface 210a of the metal plate 210 facing the electrolyte membrane / electrode structure 12 and the opposite surface 210b. Then, the resin frame members 212a and 212b are formed by removing the resin material from the convex-side surfaces 210ae and 210be of the metal plate 210. A coating 190 having conductivity and corrosion resistance is provided on the surfaces 210ae and 210be as necessary. The resin frame member 212a is provided with an end oxidizing gas channel groove 44ae.

  In the eighth embodiment configured as described above, the same effect as in the seventh embodiment can be obtained.

10, 60, 80, 100, 140, 160, 180, 200 ... Fuel cell 12, 102 ... Electrolyte membrane / electrode structure 14, 16, 62, 64, 82, 84, 104, 106, 142, 144, 162, 164, 182, 184, 202, 204 ... metal separator 18, 108 ... solid polymer electrolyte membrane 20 ... cathode electrode 20a ... cathode side gas diffusion layer 20b ... cathode electrode catalyst layer 22 ... anode electrode 22a ... anode side gas diffusion layer 22b ... Anode electrode catalyst layer 24a ... oxidant gas inlet communication hole 24b ... oxidant gas outlet communication hole 26a ... cooling medium inlet communication hole 26b ... cooling medium outlet communication hole 28a ... fuel gas inlet communication hole 28b ... fuel gas outlet communication hole 30 40, 66, 72, 86, 92, 110, 118, 146, 152, 166, 172, 186, 19 , 206, 210 ... metal plates 32, 42, 68, 74, 88, 94, 112, 120, 148, 154, 168, 174, 188a, 188b, 194a, 194b, 208a, 208b, 212a, 212b ... resin frame members 34 ... Fuel gas passage 34a ... Fuel gas passage groove 34ae ... End fuel gas passage groove 36a, 45a ... Convex portions 36b, 45b ... Concavity 44 ... Oxidant gas passage 44a ... Oxidant gas passage groove 44ae ... End oxidant gas channel groove 46 ... cooling medium channel 48, 50, 126, 128 ... seal member 70, 76, 150, 156 ... polymerization site 90, 96, 170, 176 ... embedded site 114, 122 ... inlet buffer Part 116, 124 ... outlet buffer part 190 ... coating

Claims (6)

The electrolyte membrane / electrode structure provided with electrodes having an electrode catalyst layer and a gas diffusion layer on both sides of the solid polymer electrolyte membrane is sandwiched between a pair of metal separators whose plate surfaces are formed into wave shapes, and The metal separator is a fuel cell in which a reaction gas flow path for supplying a reaction gas along the electrode surface is formed,
A resin frame member is integrally provided on the outer periphery of the metal separator,
The metal separator and the resin frame member are alternately formed with convex portions in contact with the electrolyte membrane / electrode structure and concave portions spaced apart from the electrolyte membrane / electrode structure, and a plurality of reactions along the concave portion. By forming the gas flow channel groove, the reaction gas flow channel is provided,
The reaction gas channel groove has an end reaction gas channel groove disposed outward in the width direction intersecting the reaction gas flow direction of the reaction gas channel,
The end reaction gas flow channel groove is provided on the resin frame member while facing the outer peripheral end of the electrode catalyst layer . The electrolyte membrane / electrode structure provided with electrodes having an electrode catalyst layer and a gas diffusion layer on both sides of the solid polymer electrolyte membrane is sandwiched between a pair of metal separators whose plate surfaces are formed into wave shapes, and The metal separator is a fuel cell in which a reaction gas flow path for supplying a reaction gas along the electrode surface is formed,
A resin frame member is integrally provided on the outer periphery of the metal separator,
The metal separator and the resin frame member are alternately formed with convex portions in contact with the electrolyte membrane / electrode structure and concave portions spaced apart from the electrolyte membrane / electrode structure, and a plurality of reactions along the concave portion. By forming the gas flow channel groove, the reaction gas flow channel is provided,
The reaction gas channel groove has an end reaction gas channel groove that is arranged outside the width direction intersecting the reaction gas flow direction of the reaction gas channel and allows the reaction gas to flow in the power generation region. And
The fuel cell, wherein the end reaction gas flow channel groove is provided in the resin frame member. The fuel cell according to claim 1 or 2, wherein the resin frame member has a reaction gas communication hole through which the reaction gas flows in the stacking direction with the electrolyte membrane / electrode structure,
A buffer portion connecting the reaction gas flow path and the reaction gas communication hole;
Is a fuel cell, which is integrally provided.   4. The fuel cell according to claim 1, wherein each electrode catalyst layer has a different surface area, and the electrode catalyst layer of one of the electrodes is disposed on an outer periphery of the solid polymer electrolyte membrane. 5. A fuel cell characterized in that there is provided a portion where only the gas exists.   5. The fuel cell according to claim 1, wherein a front end or a rear end in the gas flow direction of the reaction gas flow channel is located outside the electrode catalyst layer. Fuel cell.   The fuel cell according to any one of claims 1 to 5, wherein an outer peripheral end portion of the metal separator extends to an outer peripheral end portion of the resin frame member.

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