CN112216844A

CN112216844A - Fuel cell stack

Info

Publication number: CN112216844A
Application number: CN202010650807.5A
Authority: CN
Inventors: 大森优; 后藤修平; 石田坚太郎; 大久保拓郎
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 2019-07-09
Filing date: 2020-07-08
Publication date: 2021-01-12
Anticipated expiration: 2040-07-08
Also published as: JP2021012838A; CN112216844B; JP7033107B2

Abstract

The present disclosure relates to fuel cell stacks. A fastening load in the stacking direction of the power generation cells (12) is applied to the stacked body (14) of the fuel cell stack (10). A first corrugated convex part (70) is integrally provided on the outer side of a sealing boss part (51) in a first metal separator (30), and a second corrugated convex part (80) is integrally provided on the outer side of a sealing boss part (61) in a second metal separator (32). The first wavy projections (70) and the second wavy projections (80) overlap with each other in a state where phases of the waveforms are shifted from each other when viewed from the stacking direction.

Description

Fuel cell stack

Technical Field

The present invention relates to a fuel cell stack.

Background

The fuel cell stack includes a stack body in which a plurality of power generation unit cells each having an electrolyte membrane-electrode assembly (MEA) in which electrodes are disposed on both sides of an electrolyte membrane and a pair of metal separators disposed on both sides of the MEA are stacked. The stacked body is subjected to a fastening load in the stacking direction.

Each of the metal separators of one group has a sealing protrusion protruding from the surface of the MEA at the position (see, for example, patent document 1). The sealing protrusion is pressed against a resin frame portion provided on the outer peripheral side of the power generation surface of the MEA by a fastening load, thereby preventing leakage of a fluid as a reaction gas or a cooling medium.

Documents of the prior art

Patent document

Patent document 1: U.S. patent application publication No. 2018/0145353 specification

Disclosure of Invention

Problems to be solved by the invention

However, when a fastening load is applied, if the sealing protrusions of the metal separators of one group are displaced from each other in the planar direction orthogonal to the stacking direction by the fastening load, a moment acts on the metal separators. In this way, the metal separator (the sealing surface of the sealing boss) is inclined with respect to the planar direction, and there is a risk that the sealability of the sealing boss is reduced.

The present invention has been made in view of such a problem, and an object thereof is to provide a fuel cell stack capable of ensuring desired sealing performance of a sealing boss.

Means for solving the problems

One aspect of the present invention is a fuel cell stack including a stack body formed by stacking a plurality of power generation cells, each power generation cell having an electrolyte membrane-electrode assembly and a pair of metal separators arranged on both sides of the electrolyte membrane-electrode assembly, wherein a fastening load in a stacking direction of the power generation cells is applied to the stack body, wherein a sealing protrusion protruding from a surface on a side where the electrolyte membrane-electrode assembly is located is formed on each of the pair of metal separators, and the sealing protrusion is pressed against a resin frame portion provided on an outer peripheral side of a power generation surface of the electrolyte membrane-electrode assembly by the fastening load, thereby preventing leakage of a fluid that is a reaction gas or a cooling medium, wherein a first corrugated protrusion protruding from the surface is integrally provided on one of the pair of metal separators on an outer side of the sealing protrusion, in the other of the pair of metal separators, a second corrugated convex portion protruding from the surface is integrally provided on an outer side of the sealing convex portion, and the first corrugated convex portion and the second corrugated convex portion overlap with each other in a state where phases of corrugations are shifted from each other when viewed in the stacking direction.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, the first wavy projections and the second wavy projections overlap each other with the resin frame portion interposed therebetween and with the phases of the waveforms shifted from each other when viewed from the stacking direction. Therefore, when the sealing protrusions of the metal separator of one set are displaced from each other in the planar direction, the first wavy protrusions and the second wavy protrusions can receive the moment acting on the metal separator. This can suppress the inclination of the metal separator (the sealing surface of the sealing protrusion) with respect to the planar direction. In addition, when the sealing beads of the metal separator pair are displaced from each other in the planar direction, the area of overlap between the first wavy beads and the second wavy beads can be prevented from decreasing when viewed in the stacking direction. Therefore, the desired sealing performance of the sealing protrusion can be ensured.

The above objects, features and advantages will be readily understood from the following description of the embodiments with reference to the accompanying drawings.

Drawings

Fig. 1 is a perspective view of a fuel cell stack according to an embodiment of the present invention.

Fig. 2 is an exploded perspective view of the power generation cell.

Fig. 3 is a structural explanatory view of the joined separators of the first metal separator as viewed from the MEA side.

Fig. 4 is a structural explanatory view of the joined separator of the second metal separator as viewed from the MEA side.

Fig. 5 is a partially omitted cross-sectional view of the fuel cell stack at a portion corresponding to the V-V line in fig. 4.

Fig. 6A is an explanatory view of the structure of the first wavy projections and the second wavy projections, and fig. 6B is an explanatory view of the structure of the first wavy projections and the second wavy projections in a state where the second metal separator is displaced in the planar direction with respect to the first metal separator.

Detailed Description

Hereinafter, a fuel cell stack according to the present invention will be described by way of preferred embodiments with reference to the accompanying drawings.

As shown in fig. 1, a polymer electrolyte fuel cell stack 10 according to an embodiment of the present invention includes a stack 14 in which a plurality of power generation cells 12 are stacked in a horizontal direction (arrow a direction) or a gravitational direction (arrow C direction). The fuel cell stack 10 is mounted on a fuel cell vehicle such as a fuel cell electric vehicle, not shown.

At one end of the laminated body 14 in the laminating direction (the direction of arrow a), a terminal plate 16a, an insulator 18a, and an end plate 20a are arranged in this order outward. At the other end of the laminated body 14 in the laminating direction, a terminal plate 16b, an insulator 18b, and an end plate 20b are arranged in this order toward the outside. The

insulators

18a and 18b are made of an insulating material such as Polycarbonate (PC) or phenol resin.

The

end plates

20a and 20b have a horizontally long (or vertically long) rectangular shape, and a connecting rod 24 is disposed between the sides. Both ends of each connecting rod 24 are fixed to the inner surfaces of the

end plates

20a, 20b, and a fastening load in the stacking direction (the direction of arrow a) is applied to the plurality of stacked power generation cells 12. The fuel cell stack 10 may be configured to include a casing having end plates (japanese: エンドプレート)20a and 20b as end plates, and the stack 14 may be housed in the casing.

As shown in fig. 2, in the power generating cell 12, the resin framed MEA28 is sandwiched by the first metal separator 30 and the second metal separator 32. The first metal separator 30 and the second metal separator 32 are formed by press-forming a cross section of a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, or a thin metal plate having a surface treatment for corrosion prevention applied to a metal surface thereof into a corrugated shape, for example.

The resin framed MEA28 includes: the electrolyte membrane-electrode assembly 28a (hereinafter, referred to as "MEA 28 a"); and a resin frame member 46 (resin frame portion, resin film) joined to and surrounding the outer peripheral portion of the MEA28a with an overlapping portion provided at the outer peripheral portion. The MEA28a has an electrolyte membrane 40, a cathode electrode 42 provided on one surface of the electrolyte membrane 40, and an anode electrode 44 provided on the other surface of 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 film of perfluorosulfonic acid containing water. The electrolyte membrane 40 can use a HC (hydrocarbon) electrolyte in addition to a fluorine electrolyte. The electrolyte membrane 40 is sandwiched by a cathode electrode 42 and an anode electrode 44.

Although not shown in detail, the cathode 42 includes a first electrode catalyst layer joined to one surface of the electrolyte membrane 40, and a first gas diffusion layer laminated on the first electrode catalyst layer. The anode 44 has a second electrode catalyst layer joined to the other surface of the electrolyte membrane 40, and a second gas diffusion layer laminated on the second electrode catalyst layer. The resin frame member 46 is provided on the outer peripheral side of the power generation face 29 of the MEA 28.

The first fuel gas discharge passage 38B1, the first coolant discharge passage 36B1, the oxygen-containing gas supply passage 34a, the second coolant discharge passage 36B2, and the second fuel gas discharge passage 38B2 are arranged in this order with one end (end in the direction of arrow B1) in the direction of arrow B (horizontal direction in fig. 2) which is the longitudinal direction of the power generation cell 12 facing downward (from one longitudinal side of the rectangular power generation cell 12 to the other longitudinal side).

In the following description, the first coolant discharge passage 36b1 may be simply referred to as "coolant discharge passage 36 b" when it is not particularly distinguished from the second coolant discharge passage 36b 2. In addition, when the first fuel gas discharge passage 38b1 is not particularly distinguished from the second fuel gas discharge passage 38b2, it may be simply referred to as "fuel gas discharge passage 38 b".

The oxygen-containing gas supply passage 34a, the coolant discharge passage 36b, and the fuel gas discharge passage 38b extend through the stack 14 (the first metal separator 30, the second metal separator 32, and the resin frame member 46), the insulator 18a, and the end plate 20a (or the terminal plate 16a) in the stacking direction.

The fuel gas discharge passage 38b discharges a fuel gas, for example, a hydrogen-containing gas, which is one of the reactant gases. The oxygen-containing gas supply passage 34a supplies an oxygen-containing gas as the other reactant gas. The coolant discharge passage 36b discharges the coolant.

The first oxygen-containing gas discharge passage 34B1, the first coolant supply passage 36a1, the fuel gas supply passage 38a, the second coolant supply passage 36a2, and the second oxygen-containing gas discharge passage 34B2 are arranged in this order with the other end edge in the direction of arrow B (the end edge in the direction of arrow B2) of the power generation cell 12 facing downward (from one long side to the other long side of the rectangular power generation cell 12).

In the following description, the first coolant supply passage 36a1 may be simply referred to as "coolant supply passage 36 a" unless the coolant supply passage 36a2 is particularly distinguished from the second coolant supply passage 36a 2. Note that, when the first oxygen-containing gas discharge passage 34b1 is not particularly distinguished from the second oxygen-containing gas discharge passage 34b2, the first oxygen-containing gas discharge passage may be simply referred to as the "oxygen-containing gas discharge passage 34 b".

The fuel gas supply passage 38a, the coolant supply passage 36a, and the oxygen-containing gas discharge passage 34b extend through the stack 14 (the first metal separator 30, the second metal separator 32, and the resin frame member 46), the insulator 18a, and the end plate 20a (or may extend through the terminal plate 16a) in the stacking direction. The fuel gas supply passage 38a supplies the fuel gas. The oxygen-containing gas discharge passage 34b discharges the oxygen-containing gas. The coolant supply passage 36a supplies a coolant.

The number, arrangement, shape, and dimensions of the oxygen-containing gas supply passage 34a, the oxygen-containing gas discharge passage 34b, the fuel gas supply passage 38a, and the fuel gas discharge passage 38b are not limited to those of the present embodiment, and may be appropriately set according to the required specifications.

In the power generating cell 12, the electrolyte membrane 40 may be protruded outward without using the resin frame member 46. In the power generating cell 12, frame-shaped films may be provided on both sides of the electrolyte membrane 40 protruding outward.

As shown in fig. 3, the oxidant gas flow field 48 (reactant gas flow field) extending in the direction of the arrow B, for example, is provided on the surface 30a of the rectangular first metal separator 30 facing the resin framed MEA 28. The oxygen-containing gas flow field 48 is fluidly connected to the oxygen-containing gas supply passage 34a and the oxygen-containing gas discharge passage 34 b. The oxidizing gas channel 48 has a linear channel groove (or a wavy channel groove) 48B between a plurality of projections 48a extending in the arrow B direction.

An inlet buffer 50a having a plurality of embossed portions is provided between the oxygen-containing gas supply passage 34a and the oxygen-containing gas flow field 48 by press molding. An outlet buffer 50b having a plurality of embossed portions is provided between the oxygen-containing gas discharge passage 34b and the oxygen-containing gas flow field 48 by press molding.

A sealing protrusion 51 for preventing leakage of fluids (fuel gas, oxidant gas, and cooling medium) is provided on the surface 30a of the first metal separator 30. In fig. 5, the sealing boss 51 includes: a boss main body 51a which is formed by press forming so as to protrude toward the resin frame member 46; and a resin member 51b fixed to the protruding end face of the boss main body 51a by printing or coating. The resin member 51b may be provided on the MEA28a side.

The cross section of the convex body 51a is formed in a trapezoidal shape. However, the cross-sectional shape of the projection main body 51a may be changed as appropriate, and may be an arc shape or the like. The resin member 51b may be omitted. The sealing boss 51 is a sealing structure that is tightly engaged with the resin frame member 46 and elastically deformed by a fastening force in the stacking direction, thereby hermetically and liquid-tightly sealing the space between the resin frame member 46 and the sealing boss.

In fig. 3, the seal projection 51 includes a plurality of communication hole projections 52(52a to 52j) and an outer projection 53.

The communication hole protrusions 52a to 52e are provided at one end edge portion (end edge portion in the direction of arrow B1) of the first metal separator 30. Specifically, the communication hole protrusion 52a surrounds the first fuel gas discharge communication hole 38b 1. The communication hole protrusion 52b surrounds the first coolant discharge communication hole 36b 1. The communication hole protrusion 52c surrounds the oxidant gas supply communication hole 34 a. The communication hole protrusion 52d surrounds the second coolant discharge communication hole 36b 2. The communication hole projection 52e surrounds the second fuel gas discharge communication hole 38b 2.

The communication hole protrusions 52f to 52j are provided at the other end edge (end edge in the direction of arrow B2) of the first metal separator 30. Specifically, the communication hole protrusion 52f surrounds the first oxidant gas discharge communication hole 34b 1. The communication hole protrusion 52g surrounds the first coolant supply communication hole 36a 1. The communication hole protrusion 52h surrounds the fuel gas supply communication hole 38 a. The communication hole protrusion 52i surrounds the second coolant supply communication hole 36a 2. The communication hole protrusion 52j surrounds the second oxidant gas discharge communication hole 34b 2.

The communication hole protrusion 52c surrounding the oxygen-containing gas supply communication hole 34a is provided with a bridge portion 54 having a plurality of channels 54t that communicate the oxygen-containing gas supply communication hole 34a with the oxygen-containing gas flow field 48. The communication hole projections 52f and 52j surrounding the oxygen-containing gas discharge communication hole 34b are provided with bridge portions 56 having a plurality of channels 56t for connecting the oxygen-containing gas discharge communication hole 34b to the oxygen-containing gas flow field 48.

The outer protrusion 53 is provided along the outer periphery of the first metal separator 30, and surrounds the oxygen-containing gas flow field 48 and surrounds the oxygen-containing gas supply passage 34a, the oxygen-containing gas discharge passage 34b, the fuel gas supply passage 38a, and the fuel gas discharge passage 38 b.

The outer protrusion 53 meanders on one end side in the longitudinal direction of the first metal separator 30 so as to extend between the communication hole protrusions 52a to 52e adjacent to each other in the short-side direction of the first metal separator 30. Therefore, the outer protrusion 53 includes three bulging

portions

53a, 53b, and 53c that partially surround the first fuel gas discharge passage 38b1, the oxygen-containing gas supply passage 34a, and the second fuel gas discharge passage 38b2, respectively, so as to bulge toward the one short side 31a (direction away from the power generation surface 29) of the first metal separator 30 on the one end side in the longitudinal direction of the first metal separator 30.

On the other end side in the longitudinal direction of the first metal separator 30, the outer protrusion 53 meanders so as to extend between the communication hole protrusions 52f to 52j adjacent to each other in the short-side direction of the first metal separator 30. Therefore, the outer protrusion 53 has three bulging

portions

53d, 53e, and 53f that partially surround the first oxygen-containing gas discharge passage 34b1, the fuel gas supply passage 38a, and the second oxygen-containing gas discharge passage 34b2, respectively, so as to bulge toward the other short side 31b (in a direction away from the power generation surface 29) of the first metal separator 30 on the other end side in the longitudinal direction of the first metal separator 30.

As shown in fig. 4, a fuel gas flow field 58 (reactant gas flow field) extending in the direction of arrow B, for example, is formed on the surface 32a of the rectangular second metal separator 32 facing the resin framed MEA 28. The fuel gas flow field 58 is fluidly connected to the fuel gas supply passage 38a and the fuel gas discharge passage 38 b. The fuel gas flow field 58 has straight flow grooves (or wave-shaped flow grooves) 58B between a plurality of projections 58a extending in the direction of arrow B.

An inlet buffer 60a having a plurality of embossed portions is provided between the fuel gas supply passage 38a and the fuel gas flow field 58 by press molding. An outlet buffer 60b having a plurality of embossed portions is provided between the fuel gas discharge passage 38b and the fuel gas flow field 58 by press molding.

A sealing protrusion 61 for preventing leakage of fluids (fuel gas, oxidant gas, and cooling medium) is provided on the surface 32a of the second metal separator 32. In fig. 5, the sealing boss 61 includes: a boss main body 61a that is press-formed to protrude toward the resin frame member 46; and a resin member 61b fixed to the protruding end surface of the boss main body 61a by printing or coating. The resin member 61b may be provided on the MEA28a side.

The cross section of the convex body 61a is formed in a trapezoidal shape. However, the cross-sectional shape of the projection main body 61a may be changed as appropriate, and may be an arc shape or the like. The resin member 61b may be omitted. The sealing boss 61 is a sealing structure that is tightly engaged with the resin frame member 46 and elastically deformed by a fastening force in the stacking direction, thereby hermetically and liquid-tightly sealing the space between the resin frame member 46 and the sealing boss.

In fig. 4, the sealing boss 61 includes a plurality of communication hole bosses 62(62a to 62j) and an outer boss 63.

The communication hole protrusions 62a to 62e are provided at one end edge portion (end edge portion in the direction of arrow B1) of the second metal separator 32. Specifically, the communication hole protrusion 62a surrounds the first fuel gas discharge communication hole 38b 1. The communication hole protrusion 62b surrounds the first coolant discharge communication hole 36b 1. The communication hole protrusion 62c surrounds the oxidant gas supply communication hole 34 a. The communication hole protrusion 62d surrounds the second coolant discharge communication hole 36b 2. The communication hole projection 62e surrounds the second fuel gas discharge communication hole 38b 2.

The communication hole protrusions 62f to 62j are provided at the other end edge portion (end edge portion in the direction of arrow B2) of the second metal separator 32. Specifically, the communication hole protrusion 62f surrounds the first oxidant gas discharge communication hole 34b 1. The communication hole protrusion 62g surrounds the first coolant supply communication hole 36a 1. The communication hole protrusion 62h surrounds the fuel gas supply communication hole 38 a. The communication hole protrusion 62i surrounds the second coolant supply communication hole 36a 2. The communication hole projection 62j surrounds the second oxidant gas discharge communication hole 34b 2.

A bridge portion 64 having a plurality of channels 64t for connecting the fuel gas supply passage 38a to the fuel gas flow field 58 is provided in the passage protrusion 62h surrounding the fuel gas supply passage 38 a. The communication hole projections 62a and 62e surrounding the fuel gas discharge communication hole 38b are provided with bridge portions 66 having a plurality of channels 66t that communicate the fuel gas discharge communication hole 38b with the fuel gas flow field 58.

The outer protrusion 63 is provided along the outer periphery of the second metal separator 32 so as to surround the fuel gas flow field 58 and surround the oxygen-containing gas supply passage 34a, the oxygen-containing gas discharge passage 34b, the fuel gas supply passage 38a, and the fuel gas discharge passage 38 b.

The outer protrusion 63 meanders on one end side in the longitudinal direction of the second metal separator 32 so as to extend between the communication hole protrusions 62a to 62e adjacent to each other in the short-side direction of the second metal separator 32. Therefore, the outer protrusion 63 includes three bulging

portions

63a, 63b, and 63c that partially surround the first fuel gas discharge passage 38b1, the oxygen-containing gas supply passage 34a, and the second fuel gas discharge passage 38b2, respectively, so as to bulge toward the one short side 35a (direction away from the power generation surface 29) of the second metal separator 32 on the one end side in the longitudinal direction of the second metal separator 32.

The outer protrusion 63 meanders on the other end side in the longitudinal direction of the second metal separator 32 so as to extend between the communication hole protrusions 62f to 62j adjacent to each other in the short-side direction of the second metal separator 32. Therefore, the outer protrusion 63 includes three bulging

portions

63d, 63e, and 63f that partially surround the first oxygen-containing gas discharge passage 34b1, the fuel gas supply passage 38a, and the second oxygen-containing gas discharge passage 34b2, respectively, so as to bulge toward the other short side 35b (in a direction away from the power generation surface 29) of the second metal separator 32 on the other end side in the longitudinal direction of the second metal separator 32.

In fig. 2, the first metal separator 30 and the second metal separator 32 are joined integrally by welding, brazing, or the like on the outer peripheries thereof to constitute a joined separator 33. Between the back surface 30b of the first metal separator 30 and the back surface 32b of the second metal separator 32 joined to each other, a coolant flow field 68 is formed that is in fluid communication with the coolant supply passage 36a and the coolant discharge passage 36 b. The coolant flow field 68 is formed by overlapping the shape of the back surface of the first metal separator 30 having the oxidant gas flow field 48 with the shape of the back surface of the second metal separator 32 having the fuel gas flow field 58.

In fig. 5, the first metal separator 30 and the second metal separator 32 constituting the bonding separator 33 are bonded to each other by a plurality of bonding wires 33 a. The bonding wire 33a is, for example, a laser bonding wire. The bonding wire 33a may be a bonded portion formed by MIG, TIG, seam welding, brazing, caulking, or the like.

As shown in fig. 3, the first metal separator 30 is integrally provided with a plurality of first wavy projections 70(70a to 70j) projecting from the surface 30a on the outer side of the sealing boss 51.

In fig. 5, the first wavy projection 70 is formed in a trapezoidal shape in cross section. However, the cross-sectional shape of the first wavy projection 70 may be appropriately changed, and may be rectangular, square, circular arc, or the like. In a fastened state in which a fastening load is applied to the laminated body 14, the protruding ends of the first wavy projections 70 contact the one surface 46a of the resin frame member 46 so that the fastening load does not substantially act on the first wavy projections 70. That is, in a state where no fastening load is applied to the stacked body 14, the height of the first wavy projection 70 is lower than the height obtained by adding the height of the sealing protrusion 51 to the height of the resin member 51 b. Therefore, in the fastened state of the laminated body 14, a fastening load acts on the sealing protrusion 51.

In fig. 3, the first wavy projections 70 are provided independently of each other in each of the plurality of

communication holes

34a, 34b, 36a, 36b, 38a, 38 b. Specifically, the first wavy projections 70a are provided corresponding to the first fuel gas discharge passage 38b 1. The first wavy projection 70a is located between one short side 31a of the first metal separator 30 and the bulging portion 53 a. The first wavy projection 70a extends along the shape of the bulging end (end on the short side 31a side) of the bulging shaped portion 53 a.

The first wavy projections 70b are provided corresponding to the first coolant discharge passage 36b 1. The first wavy projection 70b is located between one short side 31a of the first metal separator 30 and the communication hole protrusion 52 b. The first wavy projection 70b extends along the shape of the short-side 31 a-side end of the communication hole projection 52 b.

The first wavy projections 70c are provided corresponding to the oxygen-containing gas supply passage 34 a. The first wavy projection 70c is located between one short side 31a and the bulging portion 53b of the first metal separator 30. The first wavy projection 70c extends along the shape of the expanded end (end on the short side 31a side) of the expanded shape portion 53 b.

The first wavy projections 70d are provided corresponding to the second coolant discharge passage 36b 2. The first wavy projection 70d is located between one short side 31a of the first metal separator 30 and the communication hole protrusion 52 d. The first wavy projection 70d extends along the shape of the short-side 31 a-side end of the communication hole projection 52 d.

The first wavy projections 70e are provided corresponding to the second fuel gas discharge communication hole 38b 2. The first wavy projection 70e is located between one short side 31a of the first metal separator 30 and the bulging portion 53 c. The first wavy projection 70e extends along the shape of the bulging end (end on the short side 31a side) of the bulging shaped portion 53 c. The first wavy projections 70a to 70e are provided on the outer side (in the direction of arrow B1) of the outermost portion (end portion on the short side 31a side) of the sealing protrusion 51.

The first wavy projections 70f are provided corresponding to the first oxidant gas discharge communication hole 34b 1. The first wavy projection 70f is located between the other short side 31b and the bulging portion 53d of the first metal separator 30. The first wavy projection 70f extends along the shape of the bulging end (end on the short side 31b side) of the bulging-out shaped portion 53 d.

The first wavy projections 70g are provided corresponding to the first coolant supply passage 36a 1. The first wavy projection 70g is located between the other short side 31b of the first metal separator 30 and the communication hole protrusion 52 g. The first wavy projection 70g extends along the shape of the short-side 31 b-side end of the communication hole projection 52 g.

The first wavy projections 70h are provided corresponding to the fuel gas supply passage 38 a. The first wavy projection 70h is located between the other short side 31b and the bulging portion 53e of the first metal separator 30. The first wavy projection 70h extends along the shape of the bulging end (end on the short side 31b side) of the bulging-out portion 53 e.

The first wavy projections 70i are provided corresponding to the second coolant supply passage 36a 2. The first wavy projection 70i is located between the other short side 31b of the first metal separator 30 and the communication hole projection 52 i. The first wavy projection 70i extends along the shape of the short-side 31 b-side end of the communication hole projection 52 i.

The first wavy projection 70j is provided corresponding to the second oxygen-containing gas discharge passage 34b 2. The first wavy projection 70j is located between the other short side 31b and the bulging portion 53f of the first metal separator 30. The first wavy projection 70j extends along the shape of the bulging end (end on the short side 31b side) of the bulging-out shaped portion 53 f. The first wavy projections 70f to 70j are provided on the outer side (in the direction of arrow B2) of the outermost portion (end portion on the short side 31B side) of the sealing protrusion 51.

As shown in fig. 4, the second metal separator 32 is integrally provided with a plurality of second wavy projections 80(80a to 80j) projecting from the surface 32a on the outer side of the sealing boss 61.

In fig. 5, the second wavy projection 80 is formed in a trapezoidal shape in cross section. However, the cross-sectional shape of the second wavy projection 80 may be appropriately changed, and may be rectangular, square, circular arc, or the like. In a fastened state in which a fastening load is applied to the laminated body 14, the protruding ends of the second wavy projections 80 contact the other surface 46b of the resin frame member 46 so that the fastening load does not substantially act on the second wavy projections 80. That is, in a state where no fastening load is applied to the stacked body 14, the height of the second wavy convex portion 80 is lower than the height obtained by adding the height of the sealing convex portion 61 to the height of the resin member 61 b. Therefore, in the fastened state of the laminated body 14, a fastening load acts on the sealing protrusion 61.

In fig. 4, the second wavy projections 80 are provided independently of each other in each of the plurality of

communication holes

34a, 34b, 36a, 36b, 38a, 38 b. Specifically, the second wavy projections 80a are provided corresponding to the first fuel gas discharge passage 38b 1. The second wavy projection 80a is located between the one short side 35a of the second metal separator 32 and the bulging portion 63 a. The second wavy projection 80a extends along the shape of the bulging end (end on the short side 35a side) of the bulging shaped portion 63 a.

The second wavy projections 80b are provided corresponding to the first coolant discharge passage 36b 1. The second wavy projection 80b is located between the one short side 35a of the second metal separator 32 and the communication hole protrusion 62 b. The second wavy projection 80b extends along the shape of the end of the communication hole projection 62b on the short side 35a side.

The second wavy projections 80c are provided corresponding to the oxygen-containing gas supply passage 34 a. The second wavy projection 80c is located between the one short side 35a and the bulging portion 63b of the second metal separator 32. The second wavy projection 80c extends along the shape of the bulging end (end on the short side 35a side) of the bulging shaped portion 63 b.

The second wavy projections 80d are provided corresponding to the second coolant discharge passage 36b 2. The second wavy projection 80d is located between the one short side 35a of the second metal separator 32 and the communication hole projecting portion 62 d. The second wavy projection 80d extends along the shape of the end of the communication hole convex portion 62d on the short side 35a side.

The second wavy projections 80e are provided corresponding to the second fuel gas discharge communication hole 38b 2. The second wavy projection 80e is located between the one short side 35a and the bulging portion 63c of the second metal separator 32. The second wavy projection 80e extends along the shape of the bulging end (end on the short side 35a side) of the bulging shaped portion 63 c. The second wavy projections 80a to 80e are provided on the outer side (in the direction of arrow B1) of the outermost portion (end portion on the short side 35a side) of the sealing protrusion 61.

The second wavy projections 80f are provided corresponding to the first oxidant gas discharge passage 34b 1. The second wavy projection 80f is located between the other short side 35b and the bulging portion 63d of the second metal separator 32. The second wavy projection 80f extends along the shape of the bulging end (end on the short side 35b side) of the bulging shaped portion 63 d.

The second wavy projections 80g are provided corresponding to the first coolant supply passage 36a 1. The second wavy projection 80g is located between the other short side 35b of the second metal separator 32 and the communication hole protrusion 62 g. The second wavy projection 80g extends along the shape of the end of the communication hole projection 62g on the short side 35b side.

The second wavy projections 80h are provided corresponding to the fuel gas supply passage 38 a. The second wavy projection 80h is located between the other short side 35b and the bulging portion 63e of the second metal separator 32. The second wavy projection 80h extends along the shape of the bulging end (end on the short side 35b side) of the bulging-out portion 63 e.

The second wavy projections 80i are provided corresponding to the second coolant supply passage 36a 2. The second wavy projection 80i is located between the other short side 35b of the second metal separator 32 and the lower communication hole projecting portion 62 i. The second wavy projection 80i extends along the shape of the end of the communication hole projection 62i on the short side 35b side.

The second wavy projection 80j is provided corresponding to the second oxygen-containing gas discharge passage 34b 2. The second wavy projection 80j is located between the other short side 35b and the bulging portion 63f of the second metal separator 32. The second wavy projection 80j extends along the shape of the bulging end (end on the short side 35b side) of the bulging shaped portion 63 f. The second wavy projections 80f to 80j are provided on the outer side (in the direction of arrow B2) of the outermost portion (end portion on the short side 35B side) of the sealing protrusion 61.

As shown in fig. 6A, the first wavy projections 70 and the second wavy projections 80 are formed in a sine wave, for example. However, the first wavy projections 70 and the second wavy projections 80 may be non-sinusoidal waves such as rectangular waves. The first wavy projections 70 and the second wavy projections 80 may have a repeating periodic shape.

The first wavy projections 70 and the second wavy projections 80 overlap with each other in a state where the phases of the waveforms are shifted from each other when viewed from the stacking direction. Specifically, the phases of the waveforms of the first wavy projections 70 and the second wavy projections 80 are shifted from each other by a half cycle. The power generation cell 12 has a plurality of intersecting portions 82 where the first wavy projections 70 and the second wavy projections 80 intersect with each other when viewed from the stacking direction. At the intersection 82, the first wavy projection 70 and the second wavy projection 80 face each other with the resin frame member 46 interposed therebetween.

The amplitude and wavelength of the waveform of the first wavy projections 70 are set to be the same as those of the waveform of the second wavy projections 80. However, the amplitude and wavelength of the waveform of the first wavy projections 70 may be set to be different from the amplitude and wavelength of the waveform of the second wavy projections 80.

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

First, as shown in fig. 1, the oxygen-containing gas is supplied to the oxygen-containing gas supply passage 34a of the end plate 20 a. The fuel gas is supplied to the fuel gas supply passage 38a of the end plate 20 a. The coolant is supplied to the coolant supply passage 36a of the end plate 20 a.

As shown in fig. 3, the oxygen-containing gas is introduced from the oxygen-containing gas supply passage 34a into the oxygen-containing gas flow field 48 of the first metal separator 30. The oxidizing gas moves along the oxidizing gas channel 48 in the direction indicated by the arrow B and is supplied to the cathode electrode 42 of the MEA28a shown in fig. 2.

On the other hand, as shown in fig. 4, the fuel gas is introduced from the fuel gas supply passage 38a into the fuel gas flow field 58 of the second metal separator 32. The fuel gas moves in the direction of arrow B along the fuel gas flow field 58 and is supplied to the anode electrode 44 of the MEA28a shown in fig. 2.

Therefore, in each MEA28a, the oxidant gas supplied to the cathode electrode 42 and the fuel gas supplied to the anode electrode 44 are consumed by the electrochemical reaction in the second electrode catalyst layer and the first electrode catalyst layer, and power generation is performed.

Then, the oxygen-containing gas consumed by being supplied to the cathode electrode 42 is discharged in the direction of arrow a along the oxygen-containing gas discharge passage 34 b. Similarly, the fuel gas consumed by being supplied to the anode 44 is discharged in the direction of the arrow a along the fuel gas discharge passage 38 b.

The coolant supplied to the coolant supply passage 36a is introduced into the coolant flow field 68 formed between the first metal separator 30 and the second metal separator 32, and then flows in the direction indicated by the arrow B. After the MEA28a is cooled by the coolant, the coolant is discharged from the coolant discharge passage 36 b.

In this case, the present embodiment achieves the following effects.

In the present embodiment, the first corrugated convex portion 70 protruding from the surface 30a is integrally provided on the outer side of the sealing boss 51 in the first metal separator 30, and the second corrugated convex portion 80 protruding from the surface 32a is integrally provided on the outer side of the sealing boss 61 in the second metal separator 32. The first wavy projections 70 and the second wavy projections 80 overlap with each other in a state where the phases of the waveforms are shifted from each other when viewed from the stacking direction.

As shown in fig. 5, when a fastening load in the stacking direction is applied in a state where the sealing boss 51 and the sealing boss 61 are positionally offset from each other in the planar direction (direction orthogonal to the stacking direction), a moment acts on the first metal separator 30 and the second metal separator 32. However, in the present embodiment, the moments acting on the first metal separator 30 and the second metal separator 32 can be received by the first wavy projections 70 and the second wavy projections 80. This can suppress the first metal separator 30 and the second metal separator 32 (the seal surfaces of the seal protrusions 51, 61) from being inclined with respect to the planar direction.

As shown in fig. 6B, when the first metal separator 30 and the second metal separator 32 are displaced from each other in the planar direction (the direction of arrow B), the area of overlap between the first wavy projections 70 and the second wavy projections 80 (the area of the intersections 82) can be prevented from decreasing when viewed from the stacking direction. Therefore, desired sealing performance of the sealing

bosses

51, 61 can be ensured.

In a fastened state in which a fastening load is applied to the laminated body 14, the protruding ends of the first wavy projections 70 and the second wavy projections 80 contact the resin frame member 46.

With this configuration, the first metal separator 30 and the second metal separator 32 can be effectively prevented from being inclined with respect to the planar direction.

The phases of the waveforms of the first wavy projections 70 and the second wavy projections 80 are shifted from each other by a half cycle.

According to such a configuration, when the first metal separator 30 and the second metal separator 32 are displaced from each other in the planar direction (the direction of arrow B), the area of overlap of the first wavy projections 70 and the second wavy projections 80 (the area of the intersections 82) when viewed from the stacking direction can be effectively suppressed from decreasing.

The first wavy projection 70 is provided on the outer side of the outermost portion of the sealing protrusion 51. The second wavy projection 80 is provided on the outer side of the outermost portion of the sealing protrusion 61.

A plurality of

communication holes

34a, 34b, 36a, 36b, 38a, 38b for flowing a fluid, which is a reactant gas or a coolant, are formed through the first metal separator 30 and the second metal separator 32 in the stacking direction. The sealing

bosses

51, 61 include a plurality of

communication hole bosses

52, 62 that individually surround the plurality of

communication holes

34a, 34b, 36a, 36b, 38a, 38 b. The first wavy projections 70 and the second wavy projections 80 are provided independently of each other in each of the plurality of

communication holes

34a, 34b, 36a, 36b, 38a, 38 b.

With this configuration, desired sealing performance of the plurality of

communication hole protrusions

52 and 62 can be ensured.

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

At least a part of the first wavy projections 70a to 70e may be connected to each other. At least some of the first wavy projections 70f to 70j may be connected to each other. At least some of the second wavy projections 80a to 80e may be connected to each other. At least some of the second wavy projections 80f to 80j may be connected to each other.

The above embodiments are summarized as follows.

The above embodiment includes a laminate 14 in which a plurality of power generating cells 12 are laminated, the power generating cells 12 having a membrane electrode assembly 28a and a pair of metal separators 30, 32 disposed on both sides of the membrane electrode assembly, and a fastening load in the lamination direction of the power generating cells is applied to the laminate, sealing protrusions 51, 61 protruding from surfaces 30a, 32a on the side where the membrane electrode assembly is located are formed on the pair of metal separators, respectively, and the sealing protrusions are pressed against a resin frame portion 46 provided on the outer peripheral side of a power generating surface 29 of the membrane electrode assembly by the fastening load, thereby preventing leakage of a fluid as a reaction gas or a cooling medium, and in the fuel cell stack 10, in one of the pair of metal separators, a first corrugated convex portion 70 protruding from the surface is integrally provided on the outer side of the sealing bead, and a second corrugated convex portion 80 protruding from the surface is integrally provided on the outer side of the sealing bead on the other of the metal separators in the group, and the first corrugated convex portion and the second corrugated convex portion overlap with each other in a state where the phases of the waveforms are shifted from each other when viewed in the stacking direction.

In the fuel cell stack, in a fastened state in which the fastening load is applied to the stacked body, the protruding ends of the first wavy convex portions and the second wavy convex portions may contact the resin frame portion.

In the fuel cell stack, the phases of the waveforms of the first wavy projections and the second wavy projections may be shifted by half a cycle from each other.

In the fuel cell stack, the first wavy projections and the second wavy projections may be provided on the outer side of the outermost portion of the sealing projection.

In the fuel cell stack, the first wavy projections and the second wavy projections may be formed in a sinusoidal wave.

In the fuel cell stack, the amplitude and wavelength of the waveform of the first wavy projection may be set to be the same as the amplitude and wavelength of the waveform of the second wavy projection.

In the fuel cell stack, the pair of metal separators may have a plurality of

communication holes

34a, 34b, 36a, 36b, 38a, and 38b for flowing the fluid formed therethrough in the stacking direction, the sealing protrusion may include a plurality of

communication hole protrusions

52 and 62 that individually surround the plurality of communication holes, and the first wavy protrusion and the second wavy protrusion may be provided independently of each other in each of the plurality of communication holes.

In the fuel cell stack described above, the one group of metal separators may be formed in a rectangular shape, the plurality of communication holes may be arranged in a row in a short-side direction of each of the one group of metal separators at an end portion in a long-side direction of each of the one group of metal separators, the sealing protrusion may include

outer protrusions

53 and 63 provided along an outer peripheral portion of each of the one group of metal separators, the outer protrusions may meander so as to extend between communication hole protrusions adjacent to each other in the short-side direction, and the first wavy protrusion and the second wavy protrusion may extend along shapes of bulging

portions

53a, 53b, 53c, 63a, 63b, and 63c bulging in a direction away from the power generation surface in the outer protrusions.

Claims

1. A fuel cell stack (10) is provided with a laminate (14) in which a plurality of power generation cells (12) are laminated, each power generation cell having an electrolyte membrane-electrode assembly (28a) and a set of metal separators (30, 32) disposed on both sides of the electrolyte membrane-electrode assembly,

applying a fastening load in the stacking direction of the power generation cells to the stacked body,

sealing protrusions (51, 61) protruding from the surfaces (30a, 32a) of the pair of metal separators on the side where the membrane electrode assembly is located are formed,

the sealing protrusion is pressed against a resin frame portion (46) provided on the outer peripheral side of a power generation surface (29) of the membrane electrode assembly by the fastening load, thereby preventing leakage of a fluid as a reactant gas or a cooling medium,

a first corrugated convex part (70) protruding from the surface is integrally provided on one of the metal separators in the group on the outer side of the sealing convex part,

a second corrugated convex portion (80) protruding from the surface is integrally provided on the outer side of the sealing protrusion portion on the other of the pair of metal separators,

the first wavy projections and the second wavy projections overlap with each other with the phases of the waveforms shifted from each other when viewed from the stacking direction.

2. The fuel cell stack of claim 1,

in a fastened state in which the fastening load is applied to the laminated body, the protruding ends of the first wavy projections and the second wavy projections are in contact with the resin frame portion.

3. The fuel cell stack of claim 1,

the phases of the waveforms of the first wave-like projections and the second wave-like projections are shifted from each other by a half cycle.

4. The fuel cell stack of claim 1,

the first wavy projection and the second wavy projection are provided on the outer side of the outermost portion of the sealing projection, respectively.

5. The fuel cell stack of claim 1,

the first wavy projections and the second wavy projections are formed in a sinusoidal shape, respectively.

6. The fuel cell stack of claim 1,

the amplitude and wavelength of the waveform of the first wavy projection are set to be the same as those of the waveform of the second wavy projection.

7. The fuel cell stack according to any one of claims 1 to 6,

a plurality of communication holes (34a, 34b, 36a, 36b, 38a, 38b) for flowing the fluid are formed through the metal separators in the stack direction,

the sealing projection includes a plurality of communication hole projections (52, 62) individually surrounding the plurality of communication holes,

the first wavy projection and the second wavy projection are provided independently of each other in each of the plurality of communication holes.

8. The fuel cell stack of claim 7,

the group of metal separators are respectively formed in a rectangular shape,

the plurality of communication holes are arranged in a row in the short side direction of each of the metal separators in the group at the end in the long side direction of each of the metal separators in the group,

the seal bead includes outer beads (53, 63) provided along the outer peripheral portions of the metal separators of the group,

the outer projecting portion meanders so as to extend between the communication hole projecting portions adjacent to each other in the short side direction,

the first wavy projection and the second wavy projection extend along the shape of a bulging portion (53a, 53b, 53c, 63a, 63b, 63c) bulging in a direction away from the power generation surface in the outer projection.