Metal separator and fuel cell stack

Abstract

The present invention relates to a metal separator and a fuel cell stack. In a first metal separator (30) of a fuel cell stack (10), a first peripheral side sealing portion (56) has a first metal protrusion (58). A first bypass blocking portion (66) is provided in a space between a first end protrusion (48a1) and the first peripheral side sealing portion (56) to prevent bypass of oxidant gas by blocking a portion of the space, and a gap (S1) is provided between the first bypass blocking portion (66) and the first metal protrusion (58) of the first peripheral side sealing portion (56) to separate the first bypass blocking portion (66) from the first metal protrusion (58).

Description

Technical Field

[0001] The invention relates to a metal separator and a fuel cell stack. Background Art

[0002] A fuel cell stack is formed by stacking power generation cells on each other and applying a compressive load in the thickness direction of the separator. The power generation cell has an electrolyte membrane-electrode assembly (MEA) in which electrodes are arranged on both sides of the electrolyte membrane, and a group of metal separators arranged on both sides of the MEA.

[0003] Each metal separator includes: a plate-shaped separator body; a reaction gas flow path for the reaction gas to flow from one end of the separator body toward the other end along the electrode; and an outer peripheral side sealing portion that surrounds the reaction gas flow path to prevent leakage of the reaction gas. The outer peripheral side sealing portion has a metal protrusion that is integrally molded with the separator body in a manner that allows elastic deformation due to a compressive load. The top of the outer peripheral side sealing portion presses airtightly against a resin film (resin frame member) provided on the outer periphery of the MEA in a state where the metal protrusion is elastically deformed due to a compressive load.

[0004] However, as disclosed in Patent Document 1, a convex bypass prevention portion (limiting member) for preventing bypass of the reaction gas may be provided between the end of the reaction gas flow path in the flow path width direction and the metal protrusion (boundary wall). In Patent Document 1, the bypass prevention portion is connected to the metal protrusion.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent No. 5239091 Summary of the invention

[0008] In the above-mentioned prior art, since the bypass blocking portion is connected to the metal protrusion, it is difficult to elastically deform the metal protrusion due to the compressive load. Therefore, there is a risk that a desired sealing surface pressure cannot be applied to the outer peripheral sealing portion.

[0009] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a metal separator and a fuel cell stack capable of imparting a desired sealing surface pressure to an outer peripheral side sealing portion.

[0010] One embodiment of the present invention relates to a metal separator, which is used to be assembled in a fuel cell stack in a manner of being stacked on an electrolyte membrane-electrode structure formed by arranging electrodes on both sides of an electrolyte membrane. In the metal separator, when the metal separator is assembled in the fuel cell stack, a compressive load in the thickness direction of the separator is applied to the metal separator. The metal separator includes: a plate-shaped separator body; a reaction gas flow path for allowing the reaction gas to flow along the electrode from one end of the separator body toward the other end; and an outer peripheral side sealing portion, which is used to surround the reaction gas flow path to prevent leakage of the reaction gas, the outer peripheral side sealing portion having a metal protrusion, which is formed to protrude integrally with the separator body in a manner that can be elastically deformed due to the compressive load, and a bypass blocking portion for blocking a portion of the space in the flow path width direction end of the reaction gas flow path and the outer peripheral side sealing portion to prevent the reaction gas from bypassing, and a gap is provided between the bypass blocking portion and the metal protrusion to separate the bypass blocking portion from the metal protrusion.

[0011] Another embodiment of the present invention relates to a fuel cell stack, which is formed by stacking power generation cells on each other, and the fuel cell stack is given a compressive load in the thickness direction of the partition. The power generation cells have an electrolyte membrane-electrode structure formed by arranging electrodes on both sides of the electrolyte membrane, and a group of metal partitions are arranged on both sides of the electrolyte membrane-electrode structure. In the fuel cell stack, at least any one of the group of metal partitions is the above-mentioned metal partition.

[0012] According to the present invention, since the bypass blocking portion is entirely separated from the metal protrusion, the metal protrusion can be elastically deformed more easily by a compressive load than when the bypass blocking portion is connected to the metal protrusion, thereby providing a desired sealing surface pressure to the outer peripheral sealing portion.

[0013] The following embodiments will be described with reference to the accompanying drawings, and the above-mentioned objects, features, and advantages will be easily understood based on the description of the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a partially omitted exploded perspective view of a fuel cell stack incorporating a metal separator according to an embodiment of the present invention.

[0015] Figure 2 It is along Figure 1 and Figure 4 Cross-sectional view along line II-II.

[0016] Figure 3 This is a plan view of the bonded separator as viewed from the first metal separator side.

[0017] Figure 4 It is an enlarged top view of the main part of the first metal partition.

[0018] Figure 5 This is a plan view of the bonded separator as viewed from the second metal separator side.

[0019] Figure 6 It is an enlarged top view of the main part of the second metal partition.

[0020] Figure 7 This is a diagram showing a state where the second metal separator is overlapped with the first metal separator.

[0021] Figure 8 It is along Figure 4 Cross-sectional view along line VIII-VIII in FIG. DETAILED DESCRIPTION

[0022] Hereinafter, preferred embodiments of the metal separator and the fuel cell stack according to the present invention will be described with reference to the drawings.

[0023] like Figure 1 As shown, the fuel cell stack 10 involved in this embodiment is formed by stacking a plurality of power generation cells 12 in the direction of arrow symbol A. The fuel cell stack 10 is mounted on a fuel cell vehicle (not shown) in a manner such that the stacking direction of the plurality of power generation cells 12 (the direction of arrow symbol A) is along the horizontal direction (the vehicle width direction or the vehicle length direction) of the fuel cell vehicle. However, it is also possible that the fuel cell stack 10 is mounted on the fuel cell vehicle in a manner such that the stacking direction of the plurality of power generation cells 12 is along the vertical direction (the vehicle height direction) of the fuel cell vehicle. In addition, the fuel cell stack 10 can also be used as a fixed placement type.

[0024] Figure 1 In the embodiment, the power generation cell 12 is formed into a horizontally long rectangular shape. However, the power generation cell 12 may also be formed into a vertically long rectangular shape. Figure 1 and Figure 2 As shown, the power generating cell 12 includes: an electrolyte membrane-electrode assembly with a resin frame (hereinafter referred to as “MEA 28 with a resin frame”); and a first metal separator 30 and a second metal separator 32 provided on both sides of the MEA 28 with a resin frame.

[0025] The first metal separator 30 and the second metal separator 32 are formed by, for example, stamping a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, or a metal thin plate on which a surface treatment for corrosion prevention is applied to the metal surface into a corrugated shape. The first metal separator 30 of one power generation cell 12 and the second metal separator 32 of the other power generation cell 12 of the adjacent power generation cells 12 are joined together by welding, brazing, riveting, etc. to form a joint separator 35. That is, the fuel cell stack 10 is formed by alternately stacking the MEA 28 with a resin frame and the joint separator 35.

[0026] Figure 1 In the embodiment, at one end edge portion (edge ​​portion in the direction of arrow symbol B1) of the long side direction of the power generation unit cell 12, an oxidant gas inlet communication hole 34a, a coolant medium inlet communication hole 36a, and a fuel gas outlet communication hole 38b are provided in a manner that they are mutually connected in the stacking direction (direction of arrow symbol A). The oxidant gas inlet communication hole 34a, the coolant medium inlet communication hole 36a, and the fuel gas outlet communication hole 38b are arranged in a row in the direction of arrow symbol C (vertical direction). The oxidant gas inlet communication hole 34a supplies an oxidant gas, such as an oxygen-containing gas. The coolant medium inlet communication hole 36a supplies a coolant, such as water. The fuel gas outlet communication hole 38b discharges a fuel gas, such as a hydrogen-containing gas.

[0027] At the other end edge portion (edge ​​portion in the direction of arrow symbol B2) of the long side direction of the power generation unit cell 12, a fuel gas inlet communication hole 38a, a cooling medium outlet communication hole 36b, and an oxidant gas outlet communication hole 34b are provided in a manner interconnected in the stacking direction. The fuel gas inlet communication hole 38a, the cooling medium outlet communication hole 36b, and the oxidant gas outlet communication hole 34b are arranged in a row in the direction of arrow symbol C. The fuel gas inlet communication hole 38a supplies fuel gas. The cooling medium outlet communication hole 36b discharges the cooling medium. The oxidant gas outlet communication hole 34b discharges the oxidant gas. The arrangement of the oxidant gas inlet communication hole 34a and the oxidant gas outlet communication hole 34b and the fuel gas inlet communication hole 38a and the fuel gas outlet communication hole 38b is not limited to the present embodiment, and may be appropriately set according to the required specifications.

[0028] like Figure 2 As shown, the resin framed MEA 28 includes an electrolyte membrane-electrode assembly (hereinafter referred to as “MEA 29 ”) and a resin film 46 (resin frame portion) having a frame shape and provided on the outer periphery of the MEA 29 .

[0029] MEA 29 includes: an electrolyte membrane 40; and an anode electrode 42 and a cathode electrode 44 sandwiching the electrolyte membrane 40. The electrolyte membrane 40 is, for example, a solid polymer electrolyte membrane (cation exchange membrane). The solid polymer electrolyte membrane is, for example, a thin film of perfluorosulfonic acid containing water. The electrolyte membrane 40 can use a fluorine-based electrolyte or an HC (hydrocarbon)-based electrolyte.

[0030] The cathode electrode 44 includes a first electrode catalyst layer 44a joined to one surface 40a of the electrolyte membrane 40, and a first gas diffusion layer 44b stacked on the first electrode catalyst layer 44a. The anode electrode 42 includes a second electrode catalyst layer 42a joined to the other surface 40b of the electrolyte membrane 40, and a second gas diffusion layer 42b stacked on the second electrode catalyst layer 42a.

[0031] The first electrode catalyst layer 44a is formed by uniformly coating the surface of the first gas diffusion layer 44b with porous carbon particles carrying a platinum alloy on the surface and an ion conductive polymer binder. The second electrode catalyst layer 42a is formed by uniformly coating the surface of the second gas diffusion layer 42b with porous carbon particles carrying a platinum alloy on the surface and an ion conductive polymer binder. The first gas diffusion layer 44b and the second gas diffusion layer 42b are formed of carbon paper or carbon cloth.

[0032] like Figure 1 As shown, the oxidant gas inlet communication hole 34a, the coolant inlet communication hole 36a and the fuel gas outlet communication hole 38b are provided at the edge of the resin film 46 in the direction of the arrow symbol B1. The fuel gas inlet communication hole 38a, the coolant outlet communication hole 36b and the oxidant gas outlet communication hole 34b are provided at the edge of the resin film 46 in the direction of the arrow symbol B2.

[0033] like Figure 2 As shown, the resin film 46 has a first frame-shaped sheet 46a and a second frame-shaped sheet 46b. The inner periphery of the first frame-shaped sheet 46a is bonded to the outer periphery of the MEA 29. The second frame-shaped sheet 46b is bonded to the outer periphery of the first frame-shaped sheet 46a. The first frame-shaped sheet 46a and the second frame-shaped sheet 46b are bonded to each other in the thickness direction by a bonding layer 46c formed by a bonding agent. The first frame-shaped sheet 46a and the second frame-shaped sheet 46b have different thicknesses from each other. The thickness of the first frame-shaped sheet 46a is thinner than the thickness of the second frame-shaped sheet 46b.

[0034] The first frame-shaped sheet 46a and the second frame-shaped sheet 46b are made of resin material. As the constituent material of the first frame-shaped sheet 46a and the second frame-shaped sheet 24b, for example, PPS (polyphenylene sulfide), PPA (polyphthalamide), PEN (polyethylene naphthalate), PES (polyether sulfone), LCP (liquid crystal polymer), PVDF (polyvinylidene fluoride), silicone resin, fluororesin, m-PPE (modified polyphenylene ether resin), PET (polyethylene terephthalate), PBT (polybutylene terephthalate) or modified polyolefin can be cited.

[0035] The inner peripheral portion 46n of the resin film 46 (the inner peripheral portion of the first frame-shaped sheet 46a) is arranged between the outer peripheral portion of the anode electrode 42 and the outer peripheral portion of the cathode electrode 44. Specifically, the inner peripheral portion 46n of the resin film 46 is sandwiched between the outer peripheral portion of the electrolyte membrane 40 and the outer peripheral portion of the anode electrode 42. The inner peripheral portion 46n of the resin film 46 and the outer peripheral portion of the electrolyte membrane 40 are bonded by the bonding layer 46c. In addition, the inner peripheral portion 46n of the resin film 46 may be sandwiched between the electrolyte membrane 40 and the cathode electrode 44.

[0036] Furthermore, the electrolyte membrane 40 may be made to protrude outward without using the resin film 46. In addition, frame-shaped films may be provided on both sides of the electrolyte membrane 40 protruding outward.

[0037] like Figure 3 As shown, the first metal separator 30 includes a plate-shaped first separator body 31. On the surface of the first separator body 31 facing the MEA 28 with a resin frame (hereinafter referred to as "surface 31a"), for example, a corrugated oxidant gas flow path 48 extending from one end (the end in the direction of arrow symbol B1) of the first separator body 31 toward the other end (the end in the direction of arrow symbol B2) is provided.

[0038] The oxidant gas flow path 48 is connected to the oxidant gas inlet communication hole 34a and the oxidant gas outlet communication hole 34b so that fluid can flow. The oxidant gas flow path 48 has a plurality of wavy flow grooves 48b formed between a plurality of wavy protrusions 48a extending in the direction of the arrow symbol B. Therefore, in the oxidant gas flow path 48, a plurality of protrusions 48a and a plurality of flow grooves 48b are alternately arranged in the flow path width direction (arrow symbol C direction). Hereinafter, the protrusions located at both ends of the flow path width direction among the plurality of protrusions 48a are referred to as "first end protrusions 48a1". The first end protrusion 48a1 is arranged to be closer to the inner side than the outer end 44be of the first gas diffusion layer 44b. Moreover, the oxidant gas flow path 48 (protrusions 48a and flow grooves 48b) may extend linearly in the direction of the arrow symbol B.

[0039] A first inlet buffer portion 50A is provided on the surface 31a of the first separator body 31 between the oxidant gas inlet passage 34a and the oxidant gas flow path 48, and the first inlet buffer portion 50A has a plurality of embossed rows formed by a plurality of embossed portions 50a arranged in the direction of arrow symbol C. In addition, a first outlet buffer portion 50B is provided on the surface 31a of the first separator body 31 between the oxidant gas outlet passage 34b and the oxidant gas flow path 48, and the first outlet buffer portion 50B has a plurality of embossed rows formed by a plurality of embossed portions 50b.

[0040] Moreover, if Figure 1 and Figure 3 As shown, on the surface 31b of the first separator body 31 on the opposite side to the oxidant gas flow path 48, an embossed row formed by a plurality of embossed portions 51a arranged in the direction of arrow symbol C is provided between the embossed rows of the first inlet buffer portion 50A. In addition, on the surface 31b of the first separator body 31, an embossed row formed by a plurality of embossed portions 51b arranged in the direction of arrow symbol C is provided between the embossed rows of the first outlet buffer portion 50B. The embossed portions 51a and 51b constitute a buffer portion on the refrigerant surface side.

[0041] exist Figure 3 In the embodiment, a first sealing portion 52 for preventing leakage of reaction gas (e.g., oxidant gas and fuel gas) and cooling medium fluid is provided on the surface 31a of the first separator body 31. When viewed from the separator thickness direction (arrow symbol A direction), the first sealing portion 52 extends in a wavy shape. However, it is also possible that the first sealing portion 52 extends in a straight line when viewed from the separator thickness direction.

[0042] The first sealing portion 52 includes: a plurality of first communication hole sealing portions 54 that surround a plurality of communication holes (such as the oxidant gas inlet communication hole 34a) individually; and a first outer peripheral side sealing portion 56 that is provided on the outer peripheral portion of the first separator body 31. The plurality of first communication hole sealing portions 54 surround the oxidant gas inlet communication hole 34a, the oxidant gas outlet communication hole 34b, the coolant inlet communication hole 36a, the coolant outlet communication hole 36b, the fuel gas inlet communication hole 38a, and the fuel gas outlet communication hole 38b individually.

[0043] Hereinafter, the sealing portion surrounding the oxidant gas inlet connecting hole 34a among the multiple first connecting hole sealing portions 54 is referred to as the "first connecting hole sealing portion 54a", the sealing portion surrounding the oxidant gas outlet connecting hole 34b is referred to as the "first connecting hole sealing portion 54b", the sealing portion surrounding the fuel gas inlet connecting hole 38a is referred to as the "first connecting hole sealing portion 54c", and the sealing portion surrounding the fuel gas outlet connecting hole 38b is referred to as the "first connecting hole sealing portion 54d".

[0044] The first outer peripheral side sealing portion 56 is used to prevent leakage of the reaction gas (oxidant gas) and surrounds the oxidant gas flow path 48, the first inlet buffer portion 50A, the first outlet buffer portion 50B, and the plurality of first communication hole sealing portions 54a to 54d.

[0045] like Figure 2 As shown, the first sealing portion 52 includes: a first metal protrusion 58, which is formed by stamping and protruding integrally with the first separator body 31 toward the MEA 28 with a resin frame; and a first resin member 60, which is provided on the first metal protrusion 58. The cross-sectional shape of the first metal protrusion 58 is a trapezoidal shape with a front end tapered toward the protruding direction of the first metal protrusion 58.

[0046] The first metal protrusion 58 has: a pair of first protrusion side portions 59a arranged in a manner facing each other; and a first protrusion top portion 59b, which connects the protruding ends of the pair of first protrusion side portions 59a to each other. The interval between the pair of first protrusion side portions 59a gradually narrows toward the first protrusion top portion 59b. Moreover, it is also possible that the first protrusion side portion 59a is parallel to the thickness direction of the partition (the direction of the arrow symbol A). In other words, the cross-sectional shape of the first metal protrusion 58 can also be a rectangular shape.

[0047] The first resin member 60 is an elastic member fixed to the protruding end surface (outer surface of the first protrusion top 59b) of the first metal protrusion 58 by printing or coating, etc. The first resin member 60 is made of polyester fiber, for example. In addition, the first resin member 60 may not be present.

[0048] exist Figure 3 In the embodiment, a bridge portion 62 is provided in the first separator body 31 to connect the inner side (oxidant gas inlet connecting hole 34a side) and the outer side (oxidant gas flow path 48 side) of the first connecting hole sealing portion 54a. The bridge portion 62 is provided at the side of the first connecting hole sealing portion 54a surrounding the oxidant gas inlet connecting hole 34a on the oxidant gas flow path 48 side. A bridge portion 64 is provided in the first separator body 31 to connect the inner side (oxidant gas outlet connecting hole 34b side) and the outer side (oxidant gas flow path 48 side) of the first connecting hole sealing portion 54b. The bridge portion 64 is provided at the side of the first connecting hole sealing portion 54b surrounding the oxidant gas outlet connecting hole 34b on the oxidant gas flow path 48 side.

[0049] like Figure 3 and Figure 4As shown, a plurality of first blocking bypass portions 66 are provided in the space between the two ends (first end protrusions 48a1) in the flow path width direction of the oxidant gas flow path 48 and the first outer peripheral side sealing portion 56 to prevent the oxidant gas from bypassing from the oxidant gas inlet communication hole 34a to the oxidant gas outlet communication hole 34b by blocking a portion of the space. In the present embodiment, the flow path width direction of the oxidant gas flow path 48 is the direction along the short side of the rectangular first metal separator 30 (the direction of the arrow symbol C). In the extending direction of the first end protrusion 48a1 (the direction of the arrow symbol B), a plurality of first blocking bypass portions 66 are arranged at intervals. Each first blocking bypass portion 66 is a slender convex portion extending along the flow path width direction (the direction of the arrow symbol C) of the oxidant gas flow path 48.

[0050] exist Figure 4 In the embodiment, the first end protrusion 48a1 includes: a first concave curved portion 68 curved so as to be concave relative to the first outer peripheral side seal portion 56 when viewed from above in the separator thickness direction; and a first convex curved portion 70 curved so as to be protruded relative to the first outer peripheral side seal portion 56 when viewed from above in the separator thickness direction. The first outer peripheral side seal portion 56 includes: a first concave seal portion 72 curved so as to be concave relative to the first end protrusion 48a1; and a first convex seal portion 74 curved so as to be protruded relative to the first end protrusion 48a1.

[0051] Hereinafter, among the plurality of first blocking bypass portions 66, the blocking bypass portion located between the first concave curved portion 68 and the first concave sealing portion 72 is sometimes referred to as a "first blocking bypass portion 66a", and the blocking bypass portion located between the first convex curved portion 70 and the first concave sealing portion 72 is sometimes referred to as a "first blocking bypass portion 66b". The first blocking bypass portions 66a and the first blocking bypass portions 66b are alternately arranged at intervals from each other along the extending direction (arrow symbol B direction) of the first end protrusion 48a1.

[0052] One end in the long direction (length direction) of each first bypass blocking portion 66a faces the first concave seal portion 72 in a state separated from the first outer peripheral side seal portion 56. The other end in the long direction of each first bypass blocking portion 66a is integrally connected to the first concave curved portion 68. One end in the long direction of each first bypass blocking portion 66b faces the first concave seal portion 72 in a state separated from the first outer peripheral side seal portion 56. The other end in the long direction of each first bypass blocking portion 66b is integrally connected to the first convex curved portion 70.

[0053] like Figure 2 and Figure 4As shown, each first bypass blocking portion 66 has: a pair of first side walls 67a arranged to face each other in the direction of arrow symbol B; a first end wall 67b, which connects one end of the pair of first side walls 67a in the long direction to each other; and a first top wall 67c, which is arranged in a manner to connect the protruding ends of the pair of first side walls 67a. The first side wall 67a is inclined relative to the thickness direction of the partition. The cross-sectional shape of the first bypass blocking portion 66 is a trapezoidal shape. Moreover, it is also possible that the first side walls 67a on both sides of the width direction of the first bypass blocking portion 66 are parallel to the thickness direction of the partition. In other words, the cross-sectional shape of the first bypass blocking portion 66 can also be a rectangular shape.

[0054] When viewed from the thickness direction of the partition plate, the first end wall 67b is formed into a convex arc shape toward the front end of the first outer peripheral side sealing portion 56 (see Figure 4 ).exist Figure 2 In the embodiment, the first end wall 67b is inclined relative to the thickness direction of the partition. In other words, the first end wall 67b is inclined linearly from the first partition body 31 toward the first top wall 67c toward the side where the first end protrusion 48a1 is located. The surface of the first top wall 67c on the side of the MEA 28 with a resin frame is slightly separated from the resin film 46. In other words, a gap (space) is formed between the first top wall 67c and the resin film 46 (the second frame-shaped piece 46b).

[0055] The distance L1 from the surface 31a of the first partition body 31 to the outer surface of the first top wall 67c (the height of the first bypass blocking portion 66) is shorter than the distance L2 from the surface 31a of the first partition body 31 to the protruding end surface of the first outer peripheral side seal portion 56 (the outer surface of the first resin member 60) (the height of the first outer peripheral side seal portion 56). That is, the outer surface of the first top wall 67c of the first bypass blocking portion 66 is located closer to the first partition body 31 than the protruding end surface of the first outer peripheral side seal portion 56 (the outer surface of the first resin member 60).

[0056] like Figure 2 and Figure 4 As shown, a gap S1 (space) is formed between one end (first end wall 67b) of each first bypass blocking portion 66 and the first outer peripheral side sealing portion 56. That is, the first bypass blocking portion 66 is located at a position where the first bypass blocking portion 66 is separated from the first outer peripheral side sealing portion 56 (first metal protrusion 58) as a whole. In other words, a gap S1 is provided between the first bypass blocking portion 66 and the first metal protrusion 58 of the first outer peripheral side sealing portion 56 to separate the first bypass blocking portion 66 from the first metal protrusion 58.

[0057] The gap between the first metal protrusion 58 of the first outer peripheral side seal 56 and the first bypass blocking portion 66 is widened toward the protruding direction of the first metal protrusion 58. The first connecting wall 76 connecting the base of the first bypass blocking portion 66 and the base of the first metal protrusion 58 of the first outer peripheral side seal 56 is in contact with the second separator body 33 of the second metal separator 32 (see Figure 2 ).

[0058] Figure 4 In the embodiment, an intermediate convex portion 78 for supporting the outer periphery of the MEA 29 is provided between the first blocking bypass portion 66a and the first blocking bypass portion 66b adjacent to each other. The intermediate convex portion 78 protrudes toward the MEA 28 with the resin frame. A plurality of intermediate convex portions 78 are arranged one by one between the first blocking bypass portion 66a and the first blocking bypass portion 66b adjacent to each other.

[0059] A gap Sa is provided between the intermediate convex portion 78 and the first metal protrusion 58 of the first outer peripheral side seal portion 56 to separate the intermediate convex portion 78 from the first metal protrusion 58. The gap S1 between the first bypass blocking portion 66 and the first metal protrusion 58 of the first outer peripheral side seal portion 56 is smaller than the gap Sa between the intermediate convex portion 78 and the first metal protrusion 58 of the first outer peripheral side seal portion 56.

[0060] exist Figure 4 In the embodiment, for example, two intermediate convex portions 78 are arranged at intervals along the extending direction of the first end protrusion 48a1 between the first blocking bypass portion 66a and the first blocking bypass portion 66b adjacent to each other. The intermediate convex portion 78 has a shape extending in a direction intersecting the extending direction of the first end protrusion 48a1. When viewed from the stacking direction, the intermediate convex portion 78 is arranged at a position overlapping with the outer end 44be of the first gas diffusion layer 44b.

[0061] In the first metal separator 30, a first supporting convex portion 80 for supporting the cathode electrode 44 (first gas diffusion layer 44b) is provided between the first concave curved portion 68 of the first end protrusion 48a1 and the first bypass blocking portion 66a. The first supporting convex portion 80 is formed by protruding from the first separator body 31 toward the MEA 28 with a resin frame by press molding. In the present embodiment, the first supporting convex portion 80 is integrally connected to the first bypass blocking portion 66a and is integrally connected to the first concave curved portion 68 of the first end protrusion 48a1.

[0062] like Figure 2As shown, the first supporting convex portion 80 supports the cathode electrode 44 (first gas diffusion layer 44b) at a position where the MEA 29 overlaps with the resin film 46 in the thickness direction. The first supporting convex portion 80 is provided at a position corresponding to the inner peripheral portion 46n of the frame-shaped resin film 46 (a position overlapping with the inner peripheral portion 46n of the resin film 46 when viewed from the stacking direction).

[0063] like Figure 4 As shown, a recessed portion 80a is provided near the first supporting convex portion 80, which is recessed relative to the cathode electrode 44 (the back side is shaped to protrude on the refrigerant surface side). The recessed portion 80a is arranged on the longitudinal extension line of the first bypass blocking portion 66a. The recessed portion 80a is provided corresponding to each of the plurality of first supporting convex portions 80. That is, a plurality of recessed portions 80a are provided along the extension direction of the first end protrusion 48a1. Figure 2 As shown, the front end of the protruding portion, which is the back shape of the recessed portion 80 a , abuts against the second metal separator 32 adjacent to the protruding portion.

[0064] The number, position, shape, and size of each of the first blocking bypass portion 66 , the intermediate convex portion 78 , and the first supporting convex portion 80 can be appropriately set.

[0065] like Figure 5 As shown, the second metal separator 32 includes a plate-shaped second separator body 33. On the surface of the second separator body 33 facing the MEA 28 with a resin frame (hereinafter referred to as "surface 33a"), for example, a corrugated fuel gas flow path 82 extending from one end (the end in the direction of arrow symbol B1) of the second separator body 33 toward the other end (the end in the direction of arrow symbol B2) is formed.

[0066] The fuel gas flow path 82 is connected to the fuel gas inlet connecting hole 38a and the fuel gas outlet connecting hole 38b so that fluid can flow. The fuel gas flow path 82 has a plurality of wavy flow grooves 82b formed between a plurality of wavy protrusions 82a extending in the direction of arrow symbol B. Therefore, in the fuel gas flow path 82, a plurality of protrusions 82a and a plurality of flow grooves 82b are alternately arranged in the flow path width direction (arrow symbol C direction). Hereinafter, the protrusions located at both ends of the flow path width direction among the plurality of protrusions 82a are referred to as "second end protrusions 82a1". The second end protrusion 82a1 is arranged to be closer to the inside than the outer end 42be of the second gas diffusion layer 42b. Moreover, it is also possible that the fuel gas flow path 82 (protrusions 82a and flow grooves 82b) extend linearly along the direction of arrow symbol B.

[0067] A second inlet buffer portion 84A is provided on the surface 33a of the second separator body 33 between the fuel gas inlet passage 38a and the fuel gas flow path 82, and the second inlet buffer portion 84A has a plurality of embossed rows formed by a plurality of embossed portions 84a arranged in the direction of arrow symbol C. In addition, a second outlet buffer portion 84B is provided on the surface 33a of the second separator body 33 between the fuel gas outlet passage 38b and the fuel gas flow path 82, and the second outlet buffer portion 84B has a plurality of embossed rows formed by a plurality of embossed portions 84b.

[0068] Furthermore, an embossed row formed by a plurality of embossed portions 85a arranged in the direction of arrow symbol C is provided between the embossed rows of the second inlet buffer portion 84A on the surface 33b of the second separator body 33 on the opposite side to the fuel gas flow path 82. Also, an embossed row formed by a plurality of embossed portions 85b arranged in the direction of arrow symbol C is provided between the embossed rows of the second outlet buffer portion 84B on the surface 33b of the second separator body 33. The embossed portions 85a and 85b constitute a buffer portion on the refrigerant surface side.

[0069] A second sealing portion 86 for preventing leakage of reaction gas (e.g., oxidant gas and fuel gas) and cooling medium fluid is provided on the surface 33a of the second separator body 33. When viewed from the separator thickness direction (arrow symbol B direction), the second sealing portion 86 extends in a wavy shape. However, the second sealing portion 86 may also extend in a straight line when viewed from the separator thickness direction.

[0070] The second sealing portion 86 includes: a plurality of second communication hole sealing portions 88 that surround a plurality of communication holes (such as the fuel gas inlet communication hole 38a) individually; and a second outer peripheral side sealing portion 90 that is provided on the outer peripheral portion of the second separator body 33. The plurality of second communication hole sealing portions 88 surround the oxidant gas inlet communication hole 34a, the oxidant gas outlet communication hole 34b, the fuel gas inlet communication hole 38a, the fuel gas outlet communication hole 38b, the coolant inlet communication hole 36a, and the coolant outlet communication hole 36b individually.

[0071] Hereinafter, the sealing portion surrounding the fuel gas inlet connecting hole 38a among the multiple second connecting hole sealing portions 88 is referred to as the "second connecting hole sealing portion 88a", the sealing portion surrounding the fuel gas outlet connecting hole 38b is referred to as the "second connecting hole sealing portion 88b", the sealing portion surrounding the oxidant gas inlet connecting hole 34a is referred to as the "second connecting hole sealing portion 88c", and the sealing portion surrounding the oxidant gas outlet connecting hole 34b is referred to as the "second connecting hole sealing portion 88d".

[0072] The second outer peripheral side sealing portion 90 is used to prevent leakage of the reaction gas (fuel gas) and surrounds the fuel gas flow path 82, the second inlet buffer portion 84A, the second outlet buffer portion 84B, and the plurality of second communication hole sealing portions 88a to 88d.

[0073] like Figure 2 As shown, the second sealing portion 86 includes: a second metal protrusion 92, which is formed by stamping and protruding integrally with the second separator body 33 toward the MEA 28 with a resin frame; and a second resin member 94, which is provided on the second metal protrusion 92. The cross-sectional shape of the second metal protrusion 92 is a trapezoidal shape with a front end tapered toward the protruding direction of the second metal protrusion 92.

[0074] The second metal protrusion 92 has: a pair of second protrusion side portions 93a arranged in a manner facing each other; and a second protrusion top portion 93b, which connects the protruding ends of the pair of second protrusion side portions 93a to each other. The interval between the pair of second protrusion side portions 93a gradually narrows toward the second protrusion top portion 93b. Moreover, it is also possible that the second protrusion side portion 93a is parallel to the thickness direction of the partition (the direction of the arrow symbol A). In other words, the cross-sectional shape of the second metal protrusion 92 can also be a rectangular shape.

[0075] The second resin member 94 is an elastic member fixed to the protruding end surface (outer surface of the second protrusion top 93b) of the second metal protrusion 92 by printing or coating. The second resin member 94 is made of polyester fiber, for example. In addition, the second resin member 94 may not be present.

[0076] exist Figure 5 In the embodiment, a bridge portion 96 is provided in the second separator body 33 to connect the inner side (fuel gas inlet connecting hole 38a side) and the outer side (fuel gas flow path 82 side) of the second connecting hole sealing portion 88a. The bridge portion 96 is provided at the side of the second connecting hole sealing portion 88a surrounding the fuel gas inlet connecting hole 38a on the fuel gas flow path 82 side. A bridge portion 98 is provided in the second separator body 33 to connect the inner side (fuel gas outlet connecting hole 38b side) and the outer side (fuel gas flow path 82 side) of the second connecting hole sealing portion 88b. The bridge portion 98 is provided at the side of the second connecting hole sealing portion 88b surrounding the fuel gas outlet connecting hole 38b on the fuel gas flow path 82 side.

[0077] like Figure 5 and Figure 6As shown, a plurality of second blocking bypass portions 100 are provided in the space between the two ends (the second end protrusion 82a1) of the fuel gas flow path 82 in the flow path width direction and the second outer peripheral side sealing portion 90 to prevent the fuel gas from bypassing from the fuel gas inlet connecting hole 38a to the fuel gas outlet connecting hole 38b by blocking a portion of the space. In the present embodiment, the flow path width direction of the fuel gas flow path 82 is the direction along the short side of the second metal separator 32 in the rectangular shape (the direction of the arrow symbol C). In the extension direction of the second end protrusion 82a1 (the direction of the arrow symbol B), a plurality of second blocking bypass portions 100 are arranged at intervals. Each second blocking bypass portion 100 is a slender convex portion extending along the flow path width direction (the direction of the arrow symbol C) of the fuel gas flow path 82.

[0078] Figure 6 In the embodiment, the second end protrusion 82a1 includes a second concave curved portion 102 curved so as to be concave relative to the second outer peripheral side seal portion 90, and a second convex curved portion 104 curved so as to be protruded relative to the second outer peripheral side seal portion 90. The second outer peripheral side seal portion 90 includes a second concave seal portion 106 curved so as to be concave relative to the second end protrusion 82a1, and a second convex seal portion 108 curved so as to be protruded relative to the second end protrusion 82a1.

[0079] Hereinafter, among the plurality of second blocking bypass portions 100, the blocking bypass portion located between the second concave curved portion 102 and the second concave sealing portion 106 is sometimes referred to as a "second blocking bypass portion 100a", and the blocking bypass portion located between the second convex curved portion 104 and the second concave sealing portion 106 is sometimes referred to as a "second blocking bypass portion 100b". The second blocking bypass portions 100a and the second blocking bypass portions 100b are alternately arranged at intervals from each other along the extending direction (arrow symbol B direction) of the second end protrusion 82a1.

[0080] One end of each second bypass blocking portion 100a in the long direction (length direction) is opposed to the second concave seal portion 106 in a state separated from the second outer peripheral side seal portion 90. The other end of each second bypass blocking portion 100a in the long direction is separated from the second end protrusion 82a1. One end of each second bypass blocking portion 100b in the long direction is opposed to the second concave seal portion 106 in a state separated from the second outer peripheral side seal portion 90. The other end of each second bypass blocking portion 100b in the long direction is integrally connected to the second convex curved portion 104.

[0081] like Figure 2 and Figure 6As shown, each second bypass blocking portion 100 has: a pair of second side walls 101a arranged to face each other in the direction of arrow symbol B; a second end wall 101b, which connects one end of the pair of second side walls 101a to each other; and a second top wall 101c, which is provided at the protruding end of the pair of second side walls 101a. The second side wall 101a is inclined relative to the thickness direction of the partition. The cross-sectional shape of the second bypass blocking portion 100 is a trapezoidal shape. Moreover, it is also possible that the second side walls 101a on both sides of the width direction of the second bypass blocking portion 100 are parallel to the thickness direction of the partition. That is, the cross-sectional shape of the second bypass blocking portion 100 can also be a rectangular shape.

[0082] When viewed from the thickness direction of the partition plate, the second end wall 101b is formed into a convex arc shape toward the second outer peripheral side sealing portion 90 (see Figure 6 ). Figure 2 In the embodiment, the second end wall 101b is inclined relative to the thickness direction of the partition. In other words, the second end wall 101b is inclined linearly from the second partition body 33 toward the second top wall 101c and toward the side where the second end protrusion 82a1 is located. The second top wall 101c is separated from the resin film 46. In other words, a gap (space) is formed between the second top wall 101c and the resin film 46 (the first frame-shaped piece 46a).

[0083] The distance L3 from the surface 33a of the second partition body 33 to the outer surface of the second top wall 101c (the height of the second bypass blocking portion 100) is shorter than the distance L4 from the surface 33a of the second partition body 33 to the protruding end surface of the second outer peripheral side seal 90 (the outer surface of the second resin member 94) (the height of the second outer peripheral side seal 90). That is, the outer surface of the second top wall 101c of the second bypass blocking portion 100 is located closer to the second partition body 33 than the protruding end surface of the second outer peripheral side seal 90 (the outer surface of the second resin member 94).

[0084] like Figure 2 and Figure 6 As shown, a gap S2 (space) is formed between one end (second end wall 101b) of the second blocking bypass portion 100 and the second outer peripheral side sealing portion 90. That is, the second blocking bypass portion 100 is located at a position where the second blocking bypass portion 100 is separated from the second outer peripheral side sealing portion 90 (second metal protrusion 92) as a whole. In other words, a gap S2 is provided between the second blocking bypass portion 100 and the second metal protrusion 92 of the second outer peripheral side sealing portion 90 for separating the second blocking bypass portion 100 from the second metal protrusion 92.

[0085] The gap between the second metal protrusion 92 of the second outer peripheral side seal 90 and the second bypass blocking portion 100 is widened toward the protruding direction of the second metal protrusion 92. The second connecting wall 110 connecting the base of the second bypass blocking portion 100 and the base of the second metal protrusion 92 of the second outer peripheral side seal 90 is in contact with the first separator body 31 (first connecting wall 76) of the first metal separator 30 (see Figure 2 ).

[0086] exist Figure 6 In the embodiment, an intermediate convex portion 112 for supporting the outer periphery of the MEA 29 is provided between the second blocking bypass portion 100a and the second blocking bypass portion 100b adjacent to each other. The intermediate convex portion 112 protrudes toward the MEA 28 with the resin frame. A plurality of intermediate convex portions 112 are arranged one by one between the second blocking bypass portion 100a and the second blocking bypass portion 100b adjacent to each other.

[0087] A gap Sb is provided between the middle convex portion 112 and the second metal protrusion 92 of the second outer peripheral side seal portion 90 to separate the middle convex portion 112 from the second metal protrusion 92. The gap S2 between the second bypass blocking portion 100 and the second metal protrusion 92 of the second outer peripheral side seal portion 90 is smaller than the gap Sb between the middle convex portion 112 and the second metal protrusion 92 of the second outer peripheral side seal portion 90.

[0088] The arrangement direction of the plurality of intermediate convex portions 112 provided between the second blocking bypass portions 100a and 100b adjacent to each other is the same as the arrangement direction of the plurality of intermediate convex portions 78 ( Figure 4 ) are arranged in different directions. Specifically, in the present embodiment, between the second blocking bypass portion 100a and the second blocking bypass portion 100b adjacent to each other, a plurality of intermediate convex portions 112 are arranged at intervals along the direction (arrow symbol C direction) in which the second end protrusion 82a1 and the second outer peripheral side sealing portion 90 are separated. When viewed from the stacking direction, the intermediate convex portion 112 is arranged at a position overlapping with the outer peripheral region and the outer end 42be of the second gas diffusion layer 42b.

[0089] In the second metal separator 32, a second supporting convex portion 114 for supporting the anode electrode 42 (second gas diffusion layer 42b) is provided between the second concave curved portion 102 of the second end protrusion 82a1 and the second blocking bypass portion 100a. The second supporting convex portion 114 is formed on the second separator body 33 by press molding so as to protrude toward the MEA 28 with a resin frame. When viewed from the separator thickness direction, the second supporting convex portion 114 has a plan view shape that is bent in a boomerang shape along the curved shape of the second concave curved portion 102. That is, the second supporting convex portion 114 has a plan view shape that is bent in a convex shape toward the second end protrusion 82a1 side. The length of the second supporting convex portion 114 along the extension direction of the second end protrusion 82a1 (the direction of the arrow symbol B) is greater than the width of the second blocking bypass portion 100a. That is, the second supporting convex portion 114 protrudes in the extending direction of the second end protrusion 82a1 (the direction of arrow B) relative to the second blocking bypass portion 100a. The second blocking bypass portion 100a faces the longitudinal center of the second supporting convex portion 114.

[0090] The second supporting convex portion 114 has a shape similar to the first supporting convex portion 80 ( Figure 4 ) in a different shape. In the present embodiment, the second supporting convex portion 114 is arranged in a manner separated from the second concave curved portion 102 and the second bypass blocking portion 100a. Thus, the rigidity of the second metal separator 32 can be improved. Furthermore, the second supporting convex portion 114 may be formed by being integrally connected to at least one of the second concave curved portion 102 and the second bypass blocking portion 100a.

[0091] The second supporting convex portion 114 is provided at a position corresponding to the inner end 46e of the frame-shaped resin film 46 (a position overlapping the inner end 46e of the resin film 46 when viewed from the stacking direction). Figure 8 As shown, the second supporting convex portion 114 supports the anode electrode 42 (second gas diffusion layer 42 b ) at a position where the outer peripheral portion of the MEA 29 overlaps the inner peripheral portion 46 n of the resin film 46 in the thickness direction.

[0092] like Figure 7 As shown, when viewed from the stacking direction, the protrusions 48a of the oxidant gas flow path 48 and the protrusions 82a of the fuel gas flow path 82 are formed into waveforms of the same wavelength and opposite phases. The first supporting convex portions 80 of the first metal separator 30 and the second supporting convex portions 114 of the second metal separator 32 are alternately arranged along the extending direction of the protrusions 48a, 82a.

[0093] like Figure 2As shown in FIG. 1 , the first supporting convex portion 80 faces the second end protrusion 82a1 of the second metal separator 32 via the MEA 29. Figure 7 As shown, the first supporting convex portion 80 overlaps with the second end protrusion 82 a 1 of the second metal separator 32 when viewed from the stacking direction.

[0094] like Figure 8 As shown in FIG. 1 , the second supporting convex portion 114 faces the first end protrusion 48a1 of the first metal separator 30 via the MEA 29. Figure 7 As shown, the second supporting convex portion 114 overlaps with the first end protrusion 48 a 1 of the first metal separator 30 when viewed from the stacking direction.

[0095] The number, position, shape, and size of each of the second blocking bypass portion 100 , the intermediate convex portion 112 , and the second supporting convex portion 114 can be appropriately set.

[0096] like Figure 1 As shown in the figure, a cooling medium flow path 116 is formed between the surface 31b of the first separator body 31 and the surface 33b of the second separator body 33, which are joined to each other, and the cooling medium flow path 116 allows the cooling medium inlet communication hole 36a and the cooling medium outlet communication hole 36b to communicate with each other in a fluid-flowing manner. The cooling medium flow path 116 is formed by overlapping the back shape of the first metal separator 30 formed with the oxidant gas flow path 48 and the back shape of the second metal separator 32 formed with the fuel gas flow path 82.

[0097] The fuel cell stack 10 configured in this manner operates as follows.

[0098] First, if Figure 1 As shown, an oxidant gas such as oxygen-containing gas, for example, air, is supplied to the oxidant gas inlet passage 34a. A fuel gas such as hydrogen-containing gas is supplied to the fuel gas inlet passage 38a. A coolant such as pure water, ethylene glycol, or oil is supplied to the coolant inlet passage 36a.

[0099] The oxidant gas is introduced into the oxidant gas flow path 48 of the first metal separator 30 from the oxidant gas inlet passage 34a. Figure 3 As shown, the oxidant gas moves in the direction of arrow B along the oxidant gas flow path 48 and is supplied to the cathode electrode 44 of the MEA 29 .

[0100] On the other hand, Figure 1 As shown in FIG. 1 , the fuel gas is introduced from the fuel gas inlet passage 38a to the fuel gas flow path 82 of the second metal separator 32. Figure 5As shown, the fuel gas moves in the direction of arrow B along the fuel gas flow path 82 and is supplied to the anode electrode 42 of the MEA 29 .

[0101] Therefore, in each MEA 29 , the oxidant gas supplied to the cathode electrode 44 and the fuel gas supplied to the anode electrode 42 are consumed by electrochemical reactions in the first electrode catalyst layer 44 a and the second electrode catalyst layer 42 a , thereby generating electricity.

[0102] Then, if Figure 1 As shown, the oxidant gas supplied to the cathode electrode 44 and consumed flows from the oxidant gas flow path 48 to the oxidant gas outlet passage 34b, and is discharged along the oxidant gas outlet passage 34b in the direction of arrow symbol A. Similarly, the fuel gas supplied to the anode electrode 42 and consumed flows from the fuel gas flow path 82 to the fuel gas outlet passage 38b, and is discharged along the fuel gas outlet passage 38b in the direction of arrow symbol A.

[0103] The coolant supplied to the coolant inlet passage 36a is introduced into the coolant flow path 116 formed between the first metal separator 30 and the second metal separator 32 and flows in the direction of arrow B. The coolant cools the MEA 29 and is then discharged from the coolant outlet passage 36b.

[0104] In this case, the metal separators 30 , 32 and the fuel cell stack 10 according to the present embodiment achieve the following effects.

[0105] In the first metal separator 30, a gap S1 is provided between the first blocking bypass portion 66 and the first metal protrusion portion 58 of the first outer peripheral side seal portion 56 to separate the first blocking bypass portion 66 from the first metal protrusion portion 58. Therefore, compared with the case where the first blocking bypass portion 66 is connected to the first metal protrusion portion 58, the first metal protrusion portion 58 can be elastically deformed more easily by the compressive load. That is, the surface pressure (compressive load) of the first outer peripheral side seal portion 56 can be suppressed from decreasing.

[0106] In addition, a gap S2 is provided between the second bypass blocking portion 100 and the second metal protrusion 92 of the second outer peripheral side seal portion 90 to separate the second bypass blocking portion 100 from the second metal protrusion 92. Therefore, compared with the case where the second bypass blocking portion 100 is connected to the second metal protrusion 92, the second metal protrusion 92 can be easily elastically deformed by the compressive load. That is, the surface pressure (compressive load) of the second outer peripheral side seal portion 90 can be suppressed from being reduced. Therefore, the first outer peripheral side seal portion 56 and the second outer peripheral side seal portion 90 can be given a desired sealing surface pressure.

[0107] The first bypass blocking portion 66 is formed to protrude integrally with the first separator body 31 and extends in one direction (arrow B direction). The second bypass blocking portion 100 is formed to protrude integrally with the second separator body 33 and extends in one direction (arrow B direction).

[0108] According to such a configuration, the rigidity of the first metal separator 30 can be improved by the first blocking bypass portion 66 , and the rigidity of the second metal separator 32 can be improved by the second blocking bypass portion 100 .

[0109] The first blocking bypass portion 66 extends along the flow path width direction of the oxidant gas flow path 48. The second blocking bypass portion 100 extends along the flow path width direction of the fuel gas flow path 82.

[0110] According to such a configuration, the first blocking bypass portion 66 can effectively suppress the bypass of the oxidizing gas. Also, the second blocking bypass portion 100 can effectively suppress the bypass of the fuel gas.

[0111] The gap S1 between the first metal protrusion 58 of the first outer peripheral side seal 56 and the first bypass blocking portion 66 extends from the surface 31a of the first partition body 31 to the top of the first outer peripheral side seal 56 (the first resin member 60). The gap S2 between the second metal protrusion 92 of the second outer peripheral side seal 90 and the second bypass blocking portion 100 extends from the surface 33a of the second partition body 33 to the top of the second outer peripheral side seal 90 (the second resin member 94).

[0112] According to such a structure, the first metal protrusion 58 and the second metal protrusion 92 can be elastically deformed more easily by the compressive load.

[0113] The end portion (first top wall 67c) of the first blocking bypass portion 66 on the opposite side to the first partition body 31 is located closer to the first partition body 31 than the top portion of the first outer peripheral side seal portion 56. The end portion (second top wall 101c) of the second blocking bypass portion 100 on the opposite side to the second partition body 33 is located closer to the second partition body 33 than the top portion of the second outer peripheral side seal portion 90.

[0114] According to such a structure, the first top wall 67c of the first bypass blocking portion 66 can be prevented from contacting the resin film 46 (the second frame-shaped piece 46b). In addition, the second top wall 101c of the second bypass blocking portion 100 can be prevented from contacting the resin film 46 (the first frame-shaped piece 46a). As a result, the compressive load can be effectively applied to the first outer peripheral side seal portion 56 and the second outer peripheral side seal portion 90, so that the first metal protrusion portion 58 and the second metal protrusion portion 92 can be further easily elastically deformed.

[0115] The first outer peripheral side seal portion 56 extends in a wavy shape when viewed from the thickness direction of the partition, and the first bypass blocking portion 66 faces the first concave seal portion 72 of the first outer peripheral side seal portion 56 that is bent in a concave manner relative to the first end protrusion 48a1. The second outer peripheral side seal portion 90 extends in a wavy shape when viewed from the thickness direction of the partition, and the second bypass blocking portion 100 faces the second concave seal portion 106 of the second peripheral side seal portion 90 that is bent in a concave manner relative to the second end protrusion 82a1.

[0116] According to this structure, the first bypass blocking portion 66 can effectively prevent the oxidant gas from bypassing between the first concave seal portion 72 and the first end protrusion 48a1. In addition, the second bypass blocking portion 100 can effectively prevent the fuel gas from bypassing between the second concave seal portion 106 and the second end protrusion 82a1.

[0117] A plurality of gaps S1 are provided between the plurality of first blocking bypass portions 66 and the first metal protrusion portion 58 of the first outer peripheral side seal portion 56. A plurality of gaps S2 are provided between the plurality of second blocking bypass portions 100 and the second metal protrusion portion 92 of the second outer peripheral side seal portion 90.

[0118] According to such a configuration, it is possible to effectively suppress the bypass of the reaction gas (oxidant gas and fuel gas) and to apply a desired sealing surface pressure to the first outer peripheral side sealing portion 56 and the second outer peripheral side sealing portion 90 .

[0119] A plurality of first blocking bypass portions 66 are arranged at intervals along the extending direction of the oxidant gas flow path 48, and an intermediate convex portion 78 for supporting the MEA 29 (cathode electrode 44) is provided between adjacent first blocking bypass portions 66. A plurality of second blocking bypass portions 100 are arranged at intervals along the extending direction of the fuel gas flow path 82, and an intermediate convex portion 112 for supporting the MEA 29 (anode electrode 42) is provided between adjacent second blocking bypass portions 100.

[0120] According to such a configuration, the intermediate convex portion 78 can further suppress the bypass of the oxidant gas, and the intermediate convex portion 112 can further suppress the bypass of the fuel gas.

[0121] The gap S1 between the first metal protrusion 58 of the first outer peripheral side seal 56 and the first bypass blocking portion 66 is smaller than the gap Sa between the first metal protrusion 58 and the middle convex portion 78. The gap S2 between the second metal protrusion 92 of the second outer peripheral side seal 90 and the second bypass blocking portion 100 is smaller than the gap Sb between the second metal protrusion 92 and the middle convex portion 112.

[0122] According to such a configuration, the first blocking bypass portion 66 can more effectively suppress the bypass of the oxidizing gas. Also, the second blocking bypass portion 100 can more effectively suppress the bypass of the fuel gas.

[0123] The portion (first connecting wall 76) of the first metal separator 30 between the first end protrusion 48a1 and the first metal protrusion 58 of the first outer peripheral side seal 56 abuts against the second metal separator 32 adjacent to the first metal separator 30. In addition, the portion (second connecting wall 110) of the second metal separator 32 between the second end protrusion 82a1 and the second metal protrusion 92 of the second outer peripheral side seal 90 abuts against the first metal separator 30 adjacent to the second metal separator 32.

[0124] According to such a configuration, the first metal protrusion 58 of the first outer peripheral side seal portion 56 and the second metal protrusion 92 of the second outer peripheral side seal portion 90 can be elastically deformed more effectively by the compressive load.

[0125] The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

[0126] The first blocking bypass portion 66 is not limited to the example of being integrally formed with the first separator body 31, and may be a rubber member provided on the surface 31a of the first separator body 31. The same is true for the second blocking bypass portion 100.

[0127] The above-mentioned implementation modes are summarized as follows.

[0128] The above embodiment discloses a metal separator, which is used to be assembled in a fuel cell stack (10) in a manner of being stacked on an electrolyte membrane-electrode structure (29) formed by arranging electrodes (42, 44) on both sides of an electrolyte membrane (40). In the metal separator, when the metal separator is assembled in the fuel cell stack, a compressive load in the thickness direction of the separator is applied to the metal separator. The metal separator includes: a plate-shaped separator body (31, 33); a reaction gas flow path (48, 82) for allowing the reaction gas to flow along the electrode from one end of the separator body to the other end; and an outer peripheral side sealing portion (56, 90) for The reaction gas flow path is surrounded to prevent leakage of the reaction gas, the outer side sealing portion has a metal protrusion (58, 92), and the metal protrusion (58, 92) is formed to protrude integrally with the partition body in a manner that it can be elastically deformed due to the compression load, and a bypass blocking portion (66, 100) is provided in the space between the end portion (48a1, 82a1) in the flow path width direction of the reaction gas flow path and the outer side sealing portion to prevent bypass of the reaction gas by blocking a part of the space, and a gap (S1, S2) is provided between the bypass blocking portion and the metal protrusion to separate the bypass blocking portion from the metal protrusion.

[0129] In the above-mentioned metal separator, the bypass blocking portion may be formed to protrude integrally with the separator body and extend in one direction.

[0130] The blocking bypass portion may extend along a flow path width direction of the reaction gas flow path.

[0131] In the above-mentioned metal separator, the gap between the metal protrusion and the bypass blocking portion may extend from the surface (31a, 33a) of the separator body to the top (60, 94) of the outer peripheral side sealing portion.

[0132] In the above-mentioned metal separator, an end portion (67c, 101c) of the bypass blocking portion on the opposite side to the separator body may be located closer to the separator body than a top portion of the outer peripheral side sealing portion.

[0133] In the above-mentioned metal partition, the outer peripheral side sealing portion may extend in a wavy shape when viewed from the thickness direction of the partition, and the bypass blocking portion faces the concave sealing portion (72, 106) in the outer peripheral side sealing portion that is bent in a concave manner relative to the end portion in the width direction of the flow path.

[0134] The plurality of blocking bypass portions may be arranged at intervals along the extending direction of the reaction gas flow path, and a plurality of the gaps may be provided between the plurality of blocking bypass portions and the metal protrusion.

[0135] In the above-mentioned metal separator, a plurality of the blocking bypass portions may be arranged at intervals along the extension direction of the reaction gas flow path, and an intermediate convex portion (78, 112) for supporting the electrolyte membrane-electrode assembly may be provided between adjacent blocking bypass portions.

[0136] The gap between the metal protrusion and the bypass blocking portion may be smaller than the gap (Sa, Sb) between the metal protrusion and the intermediate protrusion.

[0137] The above embodiment discloses a fuel cell stack, which is formed by stacking power generation cells (12) on each other, and the fuel cell stack is given a compressive load in the thickness direction of the partition. The power generation cell has an electrolyte membrane-electrode structure formed by arranging electrodes on both sides of the electrolyte membrane, and a group of metal partitions arranged on both sides of the electrolyte membrane-electrode structure. In the fuel cell stack, at least any one of the group of metal partitions is the above-mentioned metal partition.

[0138] In the above-mentioned fuel cell stack, a portion (76, 110) of the metal separator between the end portion in the flow path width direction and the metal protrusion may abut against a metal separator adjacent to the metal separator.

Claims

1. A metal separator (30, 32) for assembling in a fuel cell stack (10) in a manner of being stacked on an electrolyte membrane-electrode structure (29) in which electrodes (42, 44) are arranged on both sides of an electrolyte membrane (40), wherein: When the metal separator is assembled in the fuel cell stack, a compressive load is applied to the metal separator in the separator thickness direction. The metal separator comprises: A plate-shaped partition body (31, 33); a reaction gas flow path (48, 82) for allowing the reaction gas to flow along the electrode from one end toward the other end of the separator body; and an outer peripheral side sealing portion (56, 90) for surrounding the reaction gas flow path to prevent leakage of the reaction gas, The outer peripheral side sealing portion has a metal protrusion (58, 92) which is formed by protruding integrally with the partition body in a manner that can be elastically deformed by the compressive load. A bypass blocking portion (66, 100) is provided in a space between an end portion (48a1, 82a1) of the reaction gas flow path in the flow path width direction and the outer peripheral side sealing portion to prevent bypass of the reaction gas by blocking a portion of the space. The bypass preventing portion is formed to protrude integrally with the partition body. A gap (S1, S2) is provided between the bypass blocking portion and the metal protrusion portion, the gap being separated from the bypass blocking portion and the metal protrusion portion by a connecting wall of the partition body connecting a base portion of the metal protrusion portion protruding from the partition body in the partition thickness direction and a base portion of the bypass blocking portion protruding from the partition body in the partition thickness direction. The metal protrusion and the bypass blocking portion are arranged on a single metal partition plate. The blocking bypass portion is provided at an end portion of the reaction gas flow path in the flow path width direction, and is not provided at the outer peripheral side sealing portion.

2. The metal separator according to claim 1, characterized in that: The bypass preventing portion extends in one direction.

3. The metal separator according to claim 2, characterized in that: The blocking bypass portion extends along a flow path width direction of the reaction gas flow path.

4. The metal separator according to claim 1, characterized in that: The gap between the metal protrusion and the bypass blocking portion extends from a surface (31a, 33a) of the separator body to a top portion (60, 94) of the outer peripheral side sealing portion.

5. The metal separator according to claim 1, characterized in that: An end portion (67c, 101c) of the bypass blocking portion on the opposite side to the separator body is located closer to the separator body than a top portion of the outer peripheral side sealing portion.

6. The metal separator according to claim 1, characterized in that: The outer peripheral sealing portion extends in a wave shape when viewed from the thickness direction of the partition. The bypass blocking portion faces a concave seal portion (72, 106) of the outer peripheral side seal portion that is curved so as to be concave relative to the end portion in the flow path width direction.

7. The metal separator according to claim 1, characterized in that: A plurality of the blocking bypass portions are arranged at intervals along the extending direction of the reaction gas flow path, A plurality of the gaps are provided between the plurality of the bypass preventing portions and the metal protrusions.

8. The metal separator according to claim 7, characterized in that: A plurality of the blocking bypass portions are arranged at intervals along the extending direction of the reaction gas flow path, An intermediate convex portion (78, 112) for supporting the membrane-electrode assembly is provided between the adjacent bypass blocking portions.

9. The metal separator according to claim 8, characterized in that: The gap between the metal protrusion and the bypass preventing portion is smaller than the gap (Sa, Sb) between the metal protrusion and the intermediate protrusion.

10. A fuel cell stack, which is formed by stacking power generation cells (12) on each other, and the fuel cell stack is given a compressive load in the thickness direction of the separator, the power generation cell has an electrolyte membrane-electrode structure formed by arranging electrodes on both sides of the electrolyte membrane and a group of metal separators arranged on both sides of the electrolyte membrane-electrode structure, in which: At least any one of the group of metal separators is the metal separator according to any one of claims 1 to 9.

11. The fuel cell stack according to claim 10, characterized in that: A portion (76, 110) of the metal separator between the end portion in the flow path width direction and the metal protrusion abuts against a metal separator adjacent to the metal separator.

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