DE102011007304A1 - Polymer electrolyte fuel cell stack - Google Patents

Abstract

A fuel cell stack in which the frame-integrated MEAs each having an MEA and a frame enclosing the MEA and having a coolant supply manifold hole; and pairs of separators, in each of which a metal separator A and a metal separator B, each having a corrugated and channel-forming central portion and an outer peripheral portion surrounding the central portion, are placed opposite one another in such a way that the outer peripheral portions are brought into contact with one another, and the metal separator A and the metal separator B has a coolant distributing hole located on the outer peripheral portion and coolant sealing members located on the rear side of the contact area of the outer peripheral portion; are stacked on top of one another, wherein the frame has the coolant sealing elements receiving recesses, the pair of separators comprising opposite surfaces of the central sections of the metal separators A and B existing coolant channels and the coolant channels and the coolant supply distribution hole connecting the coolant inlet channel, an upper part of the coolant inlet channel from an inlet groove A, which is formed on an opposite surface of the outer peripheral portion of the metal separator A and communicates with the coolant supply manifold hole, a lower part of the coolant inlet passage consists of an inlet groove B which is formed on an opposite surface of the outer peripheral portion of the metal separator B and with communicating with the central portion, a coolant sealing member A disposed on the rear side of the contact area of the outer peripheral portion of the metal separator A, the coolant supply r-manifold hole and the groove A surround, and a coolant sealing member B disposed on the back of the contact area of the outer peripheral portion of the metal separator B surround the coolant supply manifold hole.

Description

Field of engineering

The present invention relates to a polymer electrolyte fuel cell stack and a separator pair for the polymer electrolyte fuel cell stack. The present invention is characterized in particular by the structure of coolant inlet channels, coolant discharge channels and coolant sealing elements for thinner structuring of polymer electrolyte fuel cells.

State of the art

A polymer electrolyte fuel cell stack (hereinafter also referred to simply as "fuel cell stack") comprises a cell laminate in which a plurality of single cells are stacked and arranged in series. Each individual cell consists of a membrane electrode assembly (also referred to as "MEA" hereinafter) and a pair of separators both disposed on the membrane electrode assembly. The MEA has a polymer electrolyte membrane and a pair of both catalyst electrodes (anode and cathode) disposed on the polymer electrolyte membrane. The separator has gas channels for combustion or oxidation gas supply. Furthermore, it has coolant channels through which the coolant flows to control the temperature of the fuel cell stack during operation.

In the fuel cell stack, pressure is applied in the lamination direction to ensure sealing of fluid (reaction gas or refrigerant) between cells and to decrease volume resistance between cells.

As described above, the separator has the channels for the flow of reaction gas (fuel or oxidizing gas) or coolant. The combustion and oxidizing gas and coolant should be able to pass through channels that are independent of each other, so the fuel cell stack has sealing elements for sealing the areas between respective two channels (cf., for example, Patent Document 1).

1 FIG. 10 is a perspective exploded view of a fuel cell stack 1 disclosed in Patent Document 1. In the fuel cell stack 1, as shown in FIG 1 1, the fuel cell cells 2, each consisting of a frame-integrated MEA consisting of an MEA and a frame enclosing an outer circumference of the MEA 14 and a pair of separators (anode separator 15A and cathode separator 15B ) between which the frame-integrated MEA is inserted stacked on top of each other. The separators having a fuel cell stack 1 according to Patent Document 1 are metal separators manufactured by corrugating the metal sheets by press working.

2A shows an expanded view of a back surface of a frame integrated MEA 14 opposite surface of the Anodenabscheider 15A , The anode separator 15A has like in 2A represented a central section 41 on which channels are formed, as well as the central portion 41 enclosing outer peripheral portion 43 , The outer peripheral portion 43 has a coolant supply manifold hole 22 passing through the coolant and a coolant inlet channel 51 that the coolant supply manifold hole 22 and coolant channels connects. Furthermore, the anode separator 15A sealing elements 28B on to prevent the coolant from the coolant inlet duct 51 leaking to the outside.

2 B shows an expanded view of the frame integrated MEA 14 opposite surface of the cathode 15B , The cathode separator 15B also has like in 2 B represented a central section 41 on which channels are formed, as well as the central portion 41 enclosing outer peripheral portion 43 , The outer peripheral portion 43 has an oxidizing gas supply manifold hole 23 passing through the oxidizing gas and an oxidizing gas inlet channel 61 containing the oxidizing gas supply manifold hole 23 and connecting oxidation gas channels. Furthermore, the cathode separator 15B a sealing element 28C to prevent the oxidizing gas from the oxidizing gas inlet channel 61 leaking to the outside.

3A shows a disclosed in Patent Document 1 fuel cell stack 1 in cross section along the line AA in 2A and 2 B , In the fuel cell stack 1 are as in 3A illustrated sealing elements ( 27 . 28B ) between the abutting outer peripheral portions of the anode separator 15A and cathode separator 15B arranged. In the case of the fuel cell stack 1, therefore, the adjoining outer peripheral sections are located on the anode separator 15A and cathode separator 15B not in direct contact with each other.

Furthermore, a concave and convex profile ( 31 . 32 ) on each of the outer peripheral portions of the separators to prevent twisting of the separator upon application of pressure in the lamination direction (hereinafter also referred to simply as "clamping pressure").

If the outer peripheral sections of the separators are not a concave and convex profile ( 31 . 32 ) are as in 3B shown the separator turned upon exercise of clamping pressure, so that the coolant inlet channel 51 , Oxidation gas inlet channel 61 or the like can be closed.

It is also a known state of the art to form channels connecting reaction gas distributors and reaction gas channels inside a separator (see, for example, Patent Documents 2 and 3) or to provide sealing elements between height-difference regions provided on the outer peripheral portion of a separator (see, for example, Patent Documents 4 and 5) ) to restrict thickness in the lamination direction while preventing leakage of reaction gas through a space between an MEA and a separator.

It is also known in the art to place sealing elements on recesses provided on a surface opposite the MEA from a cathode separator (see, for example, Patent Documents 6 and 7) in order to prevent the MEA from twisting through the sealing elements.

List of quotations

patent literature

• Patent Document 1: Disclosure of the Japanese Patent Application JPA 2006-147258
• Patent Document 2: Disclosure of the Japanese Patent Application JPA 2003-197221
• Patent Document 3: Disclosure of US Patent Application US-2005-0238942
• Patent Document 4: Disclosure of the Japanese Patent Application JPA-2004-63094
• Patent Document 5: Disclosure of US Patent Application US-2005-0089745
• Patent Document 6: Disclosure of the Japanese Patent Application JPA 2007-329125
• Patent Document 7: Disclosure of US Patent Application US-2007-0275288

Summary of the invention

Technical task

However, with respect to the fuel cell stack 1 disclosed in Patent Document 1, wherein the sealing members are respectively disposed between the abutting separators, the clamping pressure causes the separators to rotate slightly, though a concave and convex profile is provided to prevent twisting. When the separators are twisted, the seal reliability decreases so that the reaction gas or refrigerant may leak to the outside.

Further, as in the fuel cell stack 1 disclosed in Patent Document 1, when the outer peripheral portions forming a coolant or reaction gas inlet channel have a concave and convex profile for preventing twisting, the pressure loss at the coolant or reaction gas inlet channel is increased, so that there is a possibility of supplying sufficient amount of Exclude fluid to the coolant or reaction gas channels.

In order to achieve this object, it is conceivable to bring the outer circumferential sections of the adjoining separators into contact with one another, without arranging sealing elements between the adjoining precipitators (see FIG. 4 and 5 ).

4 shows perspective view of a separator 130A and a separator 130B which abut each other in a fuel cell stack. Both the separator 130A as well as the separator 130B each have an outer peripheral portion 133 a fuel gas supply manifold hole 110 , an oxidizing gas supply manifold hole 112 a coolant supply manifold hole 114 , a fuel gas ejection manifold hole 111 , an oxidizing gas ejection manifold hole 113 and a coolant discharge manifold hole 115 on.

At the in 4 shown fuel cell stack is a separator pair 140 constructed by the outer peripheral portions of the adjoining separator 130A and 130B Let deart face that they are in contact with each other.

Further, the outer peripheral portion 133A at the separator 130B opposite surface (hereinafter also simply referred to as "opposite curses") of the separator 130A Coolant inlet channels 143 that have a central section 131A and the coolant supply manifold hole 114 connect, as well as coolant discharge channels 145 that have a central section 131 and the coolant ejection manifold hole 115 connect (s. 5 and 6 ). On the other hand, the outer peripheral portion 133A flat without coolant inlet and coolant discharge channels.

The separator 130A has on the back surface of the opposite surface of the outer peripheral portion 133A (hereinafter also referred to simply as "back surface") the fuel gas supply manifold hole 110 and fuel gas ejection manifold hole 111 enclosing fuel gas sealing elements 153A , the oxidizing gas supply manifold hole 112 and oxidizing gas ejection manifold hole 113 enclosing oxidizing gas sealing elements 155A and the coolant supply manifold hole 114 and Coolant discharge manifold hole 115 enclosing coolant sealing elements 157A ,

On the other hand, the separator 130A and 130B each on the opposite side no sealing element. Furthermore, stand in 4 the outer peripheral sections 133 the separator 130A and 130B in contact with each other. On the other hand, there are the separators 130A and 130B at the coolant inlet channels 143 and the coolant discharge channels 145 not in contact with each other to ensure coolant flow.

In this way, one can prevent twisting of separators and a reduction of sealing reliability, which are caused by clamping pressure, by the outer peripheral portions of the separator 130A and 130B contact each other.

Further, the rear surface of the outer peripheral portion has 133A of the separator 130A a rear area Y (hereinafter also referred to as "low area Y") of a region for contacting the opposing surfaces of the separators 130A and 130B (hereinafter also simply referred to as "touch area") and an area X increased in comparison with the low area Y (hereinafter also referred to simply as "high area X"). The high area X is one to the back surface of the coolant inlet passages 143 and the coolant discharge channels 145 forming surface. In other words, the high area X means an area remote from the touch area.

Im in 4 shown separator 130A , is the coolant sealing element 157A arranged on the high surface X.

But if you do that in 4 illustrated separator pair 140 applies, the fuel cell stack increases in the direction of lamination of cells, which complicates a reduction of the fuel cell stack. In the following it is under reference to 5 and 6 explains why the fouling of the fuel cell stack in the 4 illustrated separator pair 140 difficult.

5 shows an in 4 illustrated separator pairs 140 in fuel cell stack in cross section along the line β in 4 , and 6 one in 4 illustrated separator pairs 140 in fuel cell stack in cross section along the line γ in 4 ,

When in 5 and 6 The illustrated fuel cell stacks are the frame integrated MEAs 120 and the separator pairs 140 , in each of which two separators (separator 130A and separators 130B ) arranged opposite each other so that their outer peripheral portions are in contact with each other, stacked on each other.

A frame integrated MEA 120 has an MEA 121 and one the MEA 121 enclosing frame 123 on. The frame 123 has the sealing elements 157 retaining depressions 124 ,

A separator pair 140 points as in 5 and 6 illustrated coolant inlet channels 143 on that the coolant channels 141 and the coolant supply manifold hole 114 connect.

Furthermore, the sealing elements 157A formed on the high surface X. If the sealing elements are arranged in this way on the high surface X, the thickness T1 of a separator pair 140 including the sealing elements should not be smaller than the sum of the depth of the coolant inlet channels 143 and the thickness of the sealing elements 157 ,

When the sealing elements 157A Furthermore, in this way, on the high surface X, it is necessary to frame the integrated MEA 120 to perform thick. When the sealing elements 157A as in 5 and 6 are arranged on the high surface X, the thickness of the frame 123 at the area 122 in which the the sealing elements 157 receiving depressions 124 are provided (hereinafter also referred to as "the thinnest portion"), the thinnest.

The frame 123 can be shaped only if it has a certain thickness or more. When the material is off the frame 123 z. As polyphenylene sulfide (PPS), it is difficult to make it thinner than 0.5 mm. The thickness of the thinnest section 122 should therefore be set to 0.5 mm or more. The thickness T2 of a frame 123 Therefore, it can not be smaller than the sum of the depth of coolant inlet channels 143 , the height of the sealing elements and the thickness of the thinnest section 122 (eg 0.5 mm).

Furthermore, such a coolant inlet channel 143 be flattened by the sealing elements, so that it is erfördlich him with konvavem and convex profile 31 to reinforce. In an in 4 to 6 disclosed separator pair 140 therefore remains a problem of increased pressure drop at the coolant inlet channel 143 because of concave and convex profile 31 unsolvable.

Since arranged in this way on the high surface X sealing elements 157A to an increase in the thickness T1 of the separator pair 140 as well as the thickness T2 from the frame 123 lead, the fuel cell stack increases in lamination of cells.

To solve this problem, it is conceivable that the coolant sealing elements 157A to arrange on the low surface Y. However, around the coolant supply manifold hole enclosing refrigerant seal element 157A On the low surface Y, one embodiment is one of the coolant inlet channels 143 passing through low area Y erförderlich. If one is the coolant inlet channels 143 continuous low area Y on a in 4 to 6 illustrated separator pair 140 is formed, the coolant inlet channels 143 closed, allowing the coolant to the coolant channels 141 can not flow.

Technical solution

• [1] Ein Brennstoffzellenstapel, in dem mit Rahmen integrierte MEAs mit jeweils einer MEA und einem die MEA umschließenden und ein Kühlmittelzuführ-Verteilerloch aufweisenden Rahmen; und Abscheiderpaare, bei den jeweils ein Metallabscheider A und ein Metallabscheider B, die jeweils einen gewellten und Kanäle bildenden zentralen Abschnitt sowie einen den zentralen Abschnitt umschließenden Außenumfangsabschnitt aufweisen, derart gegenüberliegend gestellt sind, dass die Außenumfangsabschnitte miteinander in Berührung zu bringen, und der Metallabscheider A und der Metallabscheider B ein am Außenumfangsabschnitt angeordnetes Kühlmittel-verteilerloch und auf der Rückseite des Berührungsbereichs des Außenumfangsabschnitts angeordnete Kühlmitteldichtelemente aufweisen; aufeinander gestapelt sind, wobei der Rahmen die Kühlmitteldichtelemente aufnehmende Vertiefungen aufweist, das Abscheiderpaar aus gegenüberliegenden Flächen der zentralen Abschnitte von den Metallabscheidern A und B bestehende Kühlmittelkanäle und einen die Kühlmittelkanäle und das Kühlmittelzuführ-verteilerloch verbindenden Kühlmitteleinlasskanal aufweist, ein oberer Teil des Kühlmitteleinlasskanals aus einer Einlassnut A besteht, die auf einer gegenüberliegenden Fläche des Außenumfangsabschnittes des Metallabscheiders A ausgebildet ist und mit dem Kühlmittelzuführ-Verteilerloch in Verbindung steht, ein unterer Teil des Kühlmitteleinlasskanals aus einer Einlassnut B besteht, die auf einer gegenüberliegenden Fläche des Außenumfangsabschnitts des Metallabscheiders B ausgebildet ist und mit dem zentralen Abschnitt in Verbindung steht, ein auf der Rückseite des Berührungsbereichs des Außenumfangsabschnitts des Metallabscheiders A angeordnetes Kühlmitteldichtelement A, das Kühlmittelzuführ-Verteilerloch und die Nut A umschließen, und ein auf der Rückseite des Berührungsbereichs des Außenumfangsabschnitts des Metallabscheiders B angeordnetes Kühlmitteldichtelement B das Kühlmittelzuführ-Verteilerloch umschließen.
• [2] Der Brennstoffzellenstapel nach [1], wobei der vom Kühlmitteldichtelement A umgebene Bereich jenen einschließt, der vom Kühlmitteldichtelement B umgeben ist, und das Kühlmitteldichtelement A und das Kühlmitteldichtelement B sich nicht überlappen.
• [3] Der Brennstoffzellenstapel nach [1] oder [2], wobei der Außenumfangsabschnitt ferner ein Kühlmittelausstoß-Verteilerloch aufweist, wobei das Abscheiderpaar ferner einen Kühlmittelausstoßkanal aufweist, der die Kühlmittelkanäle und das Kühlmittelausstoß-Verteilerloch verbindet, ein oberer Teil des Kühlmitteleinlasskanals aus einer Auslassnut B besteht, die auf der gegenüberliegenden Fläche des Außenumfangsabschnitt des Metallabscheiders B ausgebildet ist und mit dem zentralen Abschnitt in Verbindung steht, und ein unterer Teil des Kühlmitteleinlasskanals aus einer Auslassnut A besteht, die auf der gegenüberliegenden Fläche des Außenumfangsabschnitts des Metallabscheiders A ausgebildet ist und mit dem Metallabscheider A und Metallabscheider in Verbindung steht.
• [4] Der Brennstoffzellenstapel nach einem von [1] bis [3], wobei der Metallabscheider A ein Anode-Abscheider ist und der Metallabscheider B ein Kathode-Abscheider ist.

The object of the present invention is to provide a fuel cell stack which can be made smaller in the lamination direction of cells, wherein coolant sealing elements are arranged on the low surface Y.

• [1] A fuel cell stack in the frame-integrated MEAs each having an MEA and a frame including the MEA and having a coolant supply manifold hole; and separator pairs wherein each of a metal separator A and a metal separator B each having a corrugated and channel-forming central portion and an outer peripheral portion enclosing the central portion are opposed to each other so as to bring the outer peripheral portions into contact with each other, and the metal separator A and the metal separator B has a coolant distribution hole disposed on the outer peripheral portion and coolant seal members disposed on the back surface of the contacting portion of the outer peripheral portion; wherein the frame comprises the refrigerant seal receiving grooves, the separator pair of opposed surfaces of the central portions of the metal separators A and B having coolant channels and a coolant channels and the coolant supply manifold hole connecting coolant inlet channel, an upper part of the coolant inlet channel of an inlet groove A, which is formed on an opposite surface of the outer peripheral portion of the metal separator A and communicates with the coolant supply manifold hole, a lower part of the coolant inlet channel consists of an inlet groove B formed on an opposite surface of the outer peripheral portion of the Metallabscheiders B and communicating with the central portion, a refrigerant gasket disposed on the rear side of the contact portion of the outer peripheral portion of the metal separator A t A, the coolant supply manifold hole and the groove A enclose, and arranged on the back of the contact area of the outer peripheral portion of the metal separator B coolant seal B enclose the coolant supply manifold hole.
• [2] The fuel cell stack according to [1], wherein the area surrounded by the coolant seal member A includes that surrounded by the coolant seal member B, and the coolant seal member A and the coolant seal member B do not overlap.
• [3] The fuel cell stack according to [1] or [2], wherein the outer peripheral portion further includes a coolant ejection manifold hole, the separator pair further comprising a coolant ejection passage connecting the coolant channels and the coolant ejection manifold hole, an upper part of the coolant inlet passage from an exhaust groove B, which is formed on the opposite surface of the outer peripheral portion of the metal separator B and communicates with the central portion, and a lower part of the coolant inlet channel consists of an outlet groove A formed on the opposite surface of the outer peripheral portion of the metal separator A and the metal separator A and metal separator is in communication.
• [4] The fuel cell stack according to any one of [1] to [3], wherein the metal separator A is an anode separator and the metal separator B is a cathode separator.

Advantageous Effects of the Invention

According to the invention, it is possible to arrange the coolant sealing members enclosing the coolant distribution hole on the low surface, so that the frame and the separator pairs can be made thin. It is therefore possible according to the invention to downsize the fuel cell stack in the direction of lamination of cells.

Brief description of the drawings

1 shows a perspective exploded view of a conventional fuel cell stack;

2A : A plan view of a conventional metal separator;

2 B : A plan view of a conventional metal separator;

3A a cross section of a conventional fuel cell stack;

3B a cross section of a conventional fuel cell stack;

4 a perspective exploded view of a pair of separators without sealing elements between adjacent separators;

5 FIG. 2: a cross section of a fuel cell stack with the in 4 disclosed separator pairs;

6 FIG. 2: a cross section of a fuel cell stack with the in 4 disclosed separator pairs;

7 a perspective view of a fuel cell stack according to the invention;

8th a cross section of the fuel cell stack according to the invention;

9 a perspective exploded view of the fuel cell stack according to the invention;

10 a perspective exploded view of a pair of separators according to the invention;

11 FIG. 3 is an enlarged perspective view of the separator pair of the invention near a coolant supply manifold hole; FIG.

12 : an expanded view of the separator pair according to the invention in cross section;

13 : an expanded view of the separator pair according to the invention in cross section;

14 FIG. 3 is an enlarged perspective view of the separator pair of the invention near a coolant ejection manifold hole; FIG.

15 : an expanded view of the separator pair according to the invention in cross section; and

16 : An expanded view of the separator according to the invention in cross section.

Description of the embodiments

The invention relates to a fuel cell stack, wherein the polymer electrolyte fuel cells are stacked on each other. The fuel cell stack according to the invention is characterized in that innovative measures on the structure of coolant inlet ducts connecting a coolant supply manifold hole and coolant ducts make it possible to reduce the size of the fuel cell stack.

In the fuel cell stack of the present invention, (1) membrane electrode assembly (hereinafter also referred to simply as "MEA") frame-integrated membrane electrode assemblies are stacked, and (2) separator pairs are stacked on each other. The fuel cell stack according to the invention may additionally comprise pantograph or end plates (s. 7 ).

(1) frame integrated MEA

The frame integrated MEA consists of (a) an MEA (membrane electrode assembly) and (b) a frame.

a) MEA (membrane electrode unit)

The MEA has a polymer electrolyte membrane and a pair of catalyst electrodes sandwiching the polymer electrolyte membrane. The catalyst electrodes consist of anode and cathode. The catalyst electrode preferably has a catalyst layer adjacent to the polymer electrolyte membrane and a gas diffusion layer laminated on the catalyst layer.

The polymer electrolyte membrane is a polymer membrane which has the function of selectively transferring protons in the wet state. The material of the polymer electrolyte membrane is not particularly limited as long as it selectively transmits protons. Examples of these materials include fluorine-containing or hydrocarbon-containing polymer electrolyte membranes and the like. Concrete examples of the fluorine-containing polymer electrolyte membrane include Nafion (registered trademark) of Dupont, Flemion (registered trademark) of Asahi Glass Co., Ltd., Aciplex (registered trademark) of Asahi Kasei Co., GORE-SELECT (registered trademark). registered trademark) of Japan Gore-Tex Inc. and the like.

The catalyst layer is a layer comprising a catalyst which promotes the redox reaction of hydrogen or oxygen. The catalyst layer is not particularly limited if it is conductive and has a catalytic activity to accelerate redox reaction of hydrogen or oxygen. The catalyst layer on the cathode side contains z. As platinum, a platinum-cobalt alloy, a platinum-nickel-cobalt alloy or the like as a catalyst. The catalyst layer on the anode side contains platinum or a platinum-ruthenium alloy or the like as a catalyst.

The catalyst layer is z. Example, prepared by a proton-conductive electrolyte and a water-repellent resin such as PTFE with carbon particles such as acetylene black, Ketjenblack or Vulcan, on which one of the above catalyst is supported, mixed, and the mixture is applied to the polymer electrolyte membrane.

The gas diffusion layer is disposed on the catalyst layer, and has air permeability to fuel or oxidizing gas and electron conductivity. The gas diffusion layer may be a carbon fiber woven or non-woven fabric as well as a carbon particle and binder porous sheet. Grooves forming reaction gas passages for passing the reaction gas to be supplied to the catalyst layer may also be formed on the gas diffusion layer.

b) frame

The frame is an element for enclosing the outer periphery of the MEA and holding the MEA. The frame receives the MEA such that the catalyst electrode can be in contact with the separator.

The frame is preferably heat and acid resistant, and is usually made of resin. Examples of the materials of such frames include polypropylene, polyphenylene sulfide (PPS), polypropylene glycol, and the like.

The frame has a fuel gas supply manifold for fuel gas supply, a fuel gas exhaust manifold for ejecting fuel gas, an oxidant gas supply manifold for oxidant gas, an oxidant gas ejection manifold for ejecting oxidant gas, a coolant supply manifold for coolant supply, and a coolant ejection manifold for ejecting coolant ,

The frame additionally has recesses for receiving sealing elements provided on the separators to be described below (see FIG. 12 , Reference number 124 ). The frame has recesses for receiving the sealing elements so that when laminated, the frame integrated MEA and separator pair may be more easily positioned.

The frame can also be made by 1) providing a mold with cavity shaped cavities, and 2) filling, cooling and hardening the material for frames as mentioned above.

(2) separator pair

The separator pair has two separators (separators A and B). One of the separators A and B is an anode separator, and the other is a cathode separator. According to the invention, the separator A may be an anode separator and the separator B a cathode separator; can also be the separator A is a cathode separator, and the separator B a Brnnstoffelektroden-separator.

The separators are a metal separator, each made by corrugation of the metal sheet. The separators A and B each have a central portion, an outer peripheral portion and sealing elements.

The central section is an area for forming reaction gas and coolant channels. Further, a portion for reaction gas distribution and that for the coolant distribution may be formed on it. According to the invention, it is possible to wave both the central sections of the two separators A and B (see embodiment 1 in FIG 8th ), as well as to wave the central portion of one of the separators A and B alone and make the other flat. When the central portion of one of the separators A and B alone is corrugated, the reaction gas channel forming grooves are formed on the gas diffusion layer.

The outer peripheral portion is an area that includes the edge of the separator and encloses the central portion. The outer peripheral portion has a fuel gas supply manifold for fuel gas supply, a fuel gas exhaust manifold for ejecting fuel gas, an oxidant gas supply manifold for oxidant gas supply, an oxidant gas ejection manifold for ejecting oxidant gas, a coolant supply manifold for coolant supply, and a coolant ejection manifold for ejecting coolant , Further, the outer peripheral portion has the inlet grooves to be described later to be described and the outlet grooves to be described later.

The separator pair of the present invention is a conductive member made by making these separators A and B opposed to each other so as to bring the outer peripheral portions into contact with each other. The separators A and B forming the separator pair can both be glued and not glued. The separator pair are the opposite surfaces of the separators A and B each other, hereinafter referred to as "opposite surfaces". On the other hand, the back surfaces of the opposed surfaces of the separators A and B are referred to as "back surfaces".

Further, in the separator pair of the present invention, the opposite surface on the outer peripheral portion of the separator A is in contact with that on the outer peripheral portion of the separator B. An area where the opposite surface of the outer peripheral portion of the separator A is in contact with that of the outer peripheral portion of the separator B is hereinafter referred to as "touch area".

The separator pair has reaction gas and coolant channels. The reaction gas passages are formed by the back surfaces of the central portions of the separators A and B, while the coolant passages through the opposite surfaces of the central portions of the separators A and B.

The separator pair further includes coolant inlet channels connecting the coolant channels and the coolant supply manifold hole, and coolant ejection channels connecting the coolant channels and the coolant discharge manifold hole. The separator pair may additionally have coolant distribution sections between the coolant inlet channels and the coolant channels and between the coolant discharge channels and the coolant channels (see FIG. 12 and 15 ). The number of refrigerant inlet and coolant discharge channels having a pair of separators is not particularly limited, and is usually 10 to 15.

The coolant inlet and coolant ejection channels are formed by the inlet and outlet grooves as described above. In detail, the inlet and outlet grooves are formed on the opposite surfaces of the outer peripheral portions. The present invention is characterized in that, by means of innovative measures on structure of inlet and outlet grooves, the low area passing through the coolant inlet and outlet channels in plan view is formed on the back faces of the separators without the coolant inlet and outlet channels close. Here, "low areas" are understood to mean the areas of the rear surfaces of the separators A and B on the back of the contact areas and the areas at the same level as the areas on the back of the contact areas on the areas of the rear surfaces of the separators A and B. Im The following explains the structure of inlet and outlet grooves.

a) The structure of inlet grooves

The present invention is characterized in that the structure of the inlet grooves A from the separator A differs from that of the inlet grooves B from the separator B.

Specifically, the inlet grooves A from the separator A communicate with the coolant supply manifold hole, not with the central portion forming the coolant channels. The back surface of the separator A therefore has a small area between the inlet grooves A and the central portion. On the other hand, the inlet grooves B from the separator B communicate with the central portion forming the coolant channels, and not with the coolant supply manifold hole (see FIG. 10 and 12 ). The back surface of the separator B thus has a small area between the coolant supply manifold hole and the inlet grooves B.

Therefore, the upper part of the coolant inlet channel consists of the inlet groove A, and the lower part of the coolant inlet channel of the inlet groove B. Further, the low surface passing through the coolant inlet channels in plan view of the separator pair is formed on the back surfaces of the separators A and B.

Further, the inlet grooves A and B communicate with each other. Thus, the coolant inlet passages connecting the coolant supply manifold hole and the central portion are formed.

b) The structure of outlet grooves

In the same way as the inlet grooves, the present invention is characterized in that the structure of the outlet grooves A from the separator A is different from that of the outlet grooves B from the separator B.

The Auslassnuten A from the separator A are z. B. with the coolant discharge manifold hole, and not with the coolant channels forming the central portion; the outlet grooves B from the separator B communicate with the central portion forming the coolant channels, and not with the coolant discharge manifold hole. Otherwise, the outlet grooves A from the separator A communicate with the central portion forming the coolant channels, and not with the coolant discharge manifold hole; the outlet grooves B from the separator B communicate with the coolant discharge manifold hole, not with the central portion forming the coolant channels.

The upper part of the coolant outlet channel therefore consists of the outlet groove A, and its lower part consists of the outlet groove B; otherwise The upper part of the refrigerant discharge passage is composed of the discharge groove B, and the lower part of the refrigerant discharge passage is the discharge groove A. Further, the low surface passing through the refrigerant discharge passages in a plan view of the separator pair is formed on the back surfaces of the separators A and B.

Further, the outlet grooves A and B communicate with each other. Thus, the coolant discharge passages connecting the central portion and the coolant supply manifold hole are formed.

In this way, the portions upstream and downstream of the coolant inlet and outlet channels are configured by the grooves formed on different separators so that the low area passing through the coolant ejection channels in plan view of the separator pair can be designed without the coolant inlet and outlet channels to close.

The sealing elements are elements for sealing reaction gas and coolant. The sealing members include outer peripheral sealing members provided on the outer periphery of a separator; Fuel gas sealing members enclosing the fuel gas supply manifold hole and the fuel gas exhaust manifold hole; Oxidizing gas sealing members enclosing the oxidizing gas supply manifold hole and the oxidizing gas ejection manifold hole; and coolant sealing members enclosing the coolant supply manifold hole and the coolant ejection manifold hole.

The present invention is characterized in that the sealing members are disposed only on the back surfaces of the outer peripheral portions, and not on the opposite surfaces. The outer peripheral portion of the separator A is therefore in contact with that of the separator B. When the outer peripheral portion of the separator A is in contact with that of the separator B, the rotation of the separator is precluded even when clamping pressure is applied. Thus, sealing is particularly reliable for the separator according to the invention.

Further, in the present invention, the separators A and B have the low area passing through the coolant inlet and outlet channels in plan view of the separator pair. Therefore, in the present invention, the coolant sealing members enclosing the coolant supply manifold hole and the coolant discharge manifold hole may be disposed on the low surface (back of the contact portions).

When arranging the coolant sealing elements A of the separator A on the low surface, it is z. For example, it is possible to arrange them so as to surround the coolant supply manifold hole and the inlet grooves A. When arranging the refrigerant seal members B of the separator B on the low surface, it is possible to arrange them so as to surround only the coolant supply manifold hole.

In this way, one can reduce the thickness of the separator pair by arranging the coolant sealing elements on the low surfaces of the outer peripheral portions. Further, arranging the entire seal members (outer peripheral seal members, fuel gas seal members and oxidizing gas seal members) on an identical area (a low area) is possible by disposing the refrigerant seal members on the low surface of the outer peripheral portions. If the entire sealing elements can be arranged on an identical surface, an identical design for cross-section and compressibility of the entire sealing elements is possible, which can prevent variations in durability between different sealing elements.

Furthermore, the coolant sealing elements A and B preferably do not overlap in plan view of the separator pair. An overlap of the coolant sealing elements A and B can be prevented, for. Example, by an area of the separator B, which surround the coolant sealing elements B, of a region of the separator A, which surround the coolant sealing elements A, will be included.

By not overlapping the separators A and B, the thinnest portion of the frame of the frame-integrated MEA can be reduced, so that the strength of the frame can be increased. Thus, the strength of the material is ensured without thickening the frame, allowing a thinner structure of the frame.

The material of sealing elements is not particularly limited if it has elasticity, and may be both thermosetting material and thermoplastic material. Examples of the thermosetting material include the silicone rubber (VQM), the ethylene-propylene rubber (EPDM), the fluororubber (FKM), and the like. Examples of thermoplastic material include the elastomer and the like.

The outer peripheral portions on the region near sealing elements are also preferably stepless and flat. More specifically, the outer peripheral portions are preferably infinitely variable in the range of 0.5 mm or less. If the area is near Sealing elements are not flat goods, there is a risk that leaked during their casting, the sealing elements from the mold, which could preclude a press molding in the desired profile. If the area near sealing elements were not flat, it was difficult to manufacture the mold according to the profile of sealing elements.

In this way, according to the invention, the thickness of the separator pair and the frame can be made thin so that a length of the fuel cell stack in the lamination direction can be reduced. Thus, according to the invention, the fuel cell stack can be downsized.

The effects of the invention will be further explained with reference to drawings. In the following, the fuel cell stack according to the invention will be described.

7 shows a perspective view of the fuel cell stack according to the invention 100 , The fuel cell stack 100 points as in 7 presented several stacked single cells. The cell laminate of single cells is by endplates 107 clamped, and with a fixing bolt 108 and a mother 109 attached.

The fuel cell stack 100 also has one of the end plates 107 a fuel gas supply port 101 a coolant supply port 102 , an oxidizing gas supply port 103 , a fuel gas discharge port 104 , a coolant discharge port 105 and an oxidizing gas discharge port 106 on. The fuel gas supply port 101 is coupled to a fuel gas supply manifold; The coolant supply port 102 is coupled to a coolant supply manifold; The oxidizing gas supply port 103 is coupled to an oxidizing gas supply manifold. Further, the fuel gas discharge port is 104 coupled with a fuel gas ejection manifold; The coolant discharge opening 105 is coupled to a coolant discharge manifold; The oxidizing gas discharge port 106 is coupled to an oxidant gas ejection manifold.

8th shows the in 7 illustrated fuel cell stack 100 in cross section along dotted line α. Further shows 9 an expanded view of the perspective exploded view of the fuel cell stack 100 ,

In the fuel cell stack 100 are like in 8th and 9 presented the frame-integrated MEAs 120 and the separator pairs 140 stacked on top of each other. The separator pair 140 consists of in the fuel cell stack 100 abutting metal separators (anode separator 130A and cathode separator 130B ).

Two the frame integrated MEA 120 pinching separator pairs 140 have the same structure as in 9 shown. There is also the frame integrated MEA 120 from an MEA 121 and one the outer periphery of the MEA 121 enclosing frame 123 , The MEA 121 further comprises a polymer electrolyte membrane 125 and a pair of the polymer electrolyte membrane 125 clamping catalyst electrodes 127 onto. 12 ).

The frame 123 has a fuel gas supply manifold hole 110 for fuel gas supply, a fuel gas exhaust manifold hole 111 for discharging fuel gas, an oxidant gas supply manifold hole 112 for oxidizing gas supply, an oxidizing gas discharge manifold hole 113 for discharging oxidizing gas, a coolant supply manifold hole 114 to the coolant supply and coolant discharge manifold hole 115 for discharging coolant.

10 shows a perspective exploded view of the in 9 illustrated separator pair 140 , The separator pair 140 will be like in 10 prepared by the anode separator 130A and the cathode separator 130B are placed opposite each other, that their outer peripheral portions 133 in contact with each other.

Each of the separators ( 130A and 130B ) has a corrugated central portion 131 , one the central section 131 surrounding outer peripheral portion 133 and on the outer peripheral portion 133 provided sealing elements.

The back surface of the central section 131 forms reaction gas channels 139 while the opposite surface of the central section 131 Coolant channels 141 forms. At the central section 131 are sections 132 for reaction gas distribution up and down of reaction gas channels 139 trained while sections 142 for coolant distribution up and down of coolant channels 141 are constructed. The back surface of the central section 131 stands with a catalyst electrode 127 the MEA 121 in touch.

The outer peripheral portion 133 has a fuel gas supply manifold hole 110 for fuel gas supply, a fuel gas exhaust manifold hole 111 for discharging fuel gas, an oxidant gas supply manifold hole 112 for oxidizing gas supply, an oxidizing gas discharge manifold hole 113 for discharging oxidizing gas, a coolant supply manifold hole 114 to the coolant supply and coolant discharge manifold hole 115 for discharging coolant.

Three inlet grooves 135A and three outlet grooves 137A are on the opposite surface the outer peripheral portion 133A of the anode separator 130A educated. The inlet grooves 135A stand with the coolant supply manifold hole 114 in connection, and not with the central section 131A , The outlet grooves 137A further, with the coolant discharge manifold hole 115 in connection, and not with the central section 131A ,

In this way, the inlet grooves connect 135A the coolant supply manifold hole 114 not directly with the central section 131A , The back surface of the anode separator 130A therefore has a low area Y between the inlet grooves 135A and the central section 131A on. The inlet grooves 135A also connect the coolant ejection manifold hole 115 not directly with the central section 131A , The back surface of the anode separator 130A therefore has a low area Y between the outlet grooves 137A and the central section 131A on.

Three inlet grooves 135B and three outlet grooves 137B are on the opposite surface of the outer peripheral portion 133B of the cathode separator 130B educated. The inlet grooves 135B stand with the central section 131B in communication, and not with the coolant supply manifold hole 114 , The outlet grooves 137B stand further with the central section 131B and not with the coolant ejection manifold hole 115 ,

In this way, the inlet grooves connect 135B the coolant supply manifold hole 114 not directly with the central section 131B , The back surface of the cathode separator 130B therefore has a low area Y between the coolant supply manifold hole 114 and the inlet grooves 135B on. The outlet grooves 137B also connect the coolant ejection manifold hole 115 not directly with the central section 131B , The back surface of the cathode separator 130B therefore has a low area Y between the coolant discharge manifold hole 115 and the outlet grooves 137B on.

The inlet grooves 135 and the outlet grooves 137 are preferably each 0.8 to 2 mm wide and 0.25 to 0.5 mm deep. If the respective width of the inlet grooves 135 and outlet grooves 137 2 mm or more, there was a risk that the grooves would be pressed by clamping pressure and the coolant inlet and coolant discharge channels would be closed. If the respective width of the inlet grooves 135 and outlet grooves 137 On the other hand, less than 0.8 mm or the depth of the grooves would be less than 0.25 mm, there would be a risk that the pressure loss at the coolant inlet and coolant discharge channels would be increased, so that a sufficient amount of coolant could not be supplied to the coolant channels ,

The sealing elements comprise outer peripheral sealing elements 151 which are provided on the outer periphery of a separator; Fuel gas sealing elements 153 that the fuel gas supply manifold hole 110 and the fuel gas ejection manifold hole 111 enclose; Oxidizing gas sealing elements 155 that the oxidizing gas supply manifold hole 112 and the oxidizing gas discharge manifold hole 113 enclose; and coolant sealing elements 157 that the coolant supply manifold hole 114 and the coolant ejection manifold hole 115 enclose.

The outer circumference sealing elements 151 prevent the reaction gas or refrigerant from leaking to the outside of the fuel cell stack. The fuel gas sealing elements 153 prevent the fuel gas from leaking to the outside for the passage of the fuel gas. The Oxidationsgasdichtelemente 155 prevent the oxidizing gas from leaking to the outside for the passage of the oxidizing gas. The coolant sealing elements 157 prevent the coolant from leaking to the outside for the passage of the coolant. Thus, the three liquids, ie fuel gas, oxidant gas and coolant, are never mixed.

The dotted line in 10 shows the on the back surface of the illustrated cathode separator 130B arranged sealing elements. The sealing elements are as in 10 shown only on the back surfaces of the outer peripheral portions 133 the separator 130 arranged, and not on the opposite surfaces of the outer peripheral portions 133 , Further, the outer peripheral portion 133A of the anode separator 130A and the outer peripheral portion 133B of the cathode separator 130B in contact with each other. The outer peripheral sections 133 the separator 130 are thus not twisted even when exercising clamping pressure.

The following are other features of the present invention, ie the coolant inlet channels 143 and the coolant sealing elements 157 , explained.

11 shows an expanded perspective view of an area near the coolant supply manifold hole 114 of the separator pair 140 , Then shows 12 an expanded view of the fuel cell stack 100 in cross section along the line β in 11 , and 13 an expanded view of the fuel cell stack 100 in cross section along the line γ in 11 ,

The separator pair 140 points as in 12 represented coolant channels 141 , Sections 142 to the coolant distribution and coolant inlet channels 143 on. The upper parts of the coolant inlet channels 143 consist of the inlet grooves 135A , and their lower parts are uas the inlet grooves 135B ,

The inlet grooves 135A and the inlet grooves 135B partially overlap. Such an overlap of the grooves 135A and 135B lets the coolant flow from upwards to downwards. The width W of a region in which the grooves 135A and 135B overlap, is usually 1 to 2 mm.

The coolant sealing element 157A encloses as in 12 shows the coolant supply manifold hole 114 and the inlet grooves 135A , and are on the low surface Ya between the inlet grooves 135A and the central section 131 arranged. The coolant sealing elements 157B enclose the coolant supply manifold hole 114 , and are on the low surface Yb between the coolant supply manifold hole 114 and the inlet grooves 135B arranged.

The coolant sealing element 157A thus overlaps an arrangement position of the inlet grooves 135B , and the coolant sealing elements 157B those of the inlet grooves 135A ,

In this way, the coolant sealing elements 157 arranged on the low areas Y, so that the thickness T1 of the separator pair 140 including the sealing portions may be at least as thin as the sum of the thickness of the metal sheets forming the separators and that of the two refrigerant sealing elements.

Furthermore, one of the coolant sealing element 157A surrounded area as in 11 and 12 shown in plan view of the separator pair 140 larger than that of the coolant sealing element 157B is surrounded, and the coolant sealing element 157A and the coolant sealing elements 157B do not overlap.

When the coolant sealing elements 157A and 157B as described above, do not overlap is the thinnest area 122 from the frame 123 only the one from the outer circumference sealing elements 151A and 151B is trapped. On the other hand, if the coolant sealing elements 157A and 157B are overlapping, that of the outer peripheral sealing elements 151A and 151B clamped area as well as that of the outer peripheral sealing elements 157A and 157B is pinched, thinnest, leaving the thinnest area 122 from the frame 123 is extended (s. 5 ).

Depending on the thinnest area expanded from the frame 123 is, the less the strength of the frame 123 is, so the thickness of the frame 123 must be increased accordingly.

If, on the other hand, as in the present invention, the thin portion of the frame 123 limited, the strength of the frame 123 can be ensured without thickening it. As a result, the frame 123 be made thinner than in the case of the extended thin area of the frame 123 ,

The following are the coolant discharge channels and the coolant sealing element 157 explained.

14 shows an expanded perspective view of the pair of separators 140 in the vicinity of the coolant discharge manifold hole 115 , Further shows 15 an expanded view of the fuel cell stack 100 in cross section along the line β in 14 , and 16 an expanded view of the fuel cell stack 100 in cross section along the line γ in 14 ,

The separator pair 140 points as in 16 represented coolant discharge channels 145 on, the sections 142 to the coolant distribution and the coolant supply manifold hole 114 connect. The upper parts of the coolant discharge channels 145 consist of the Auslassnuten 137B , and their lower part consist of the Auslassnuten 137A ,

The outlet grooves 137B and the outlet grooves 137A partially overlap. Such an overlap of the Auslassnuten 137B and 137A lets the coolant flow from upwards to downwards. The width W of a region in which the Auslassnuten 137B and the outlet grooves 137A overlap, is usually 1 to 2 mm.

The coolant sealing element 157A encloses as in 14 to 16 shows the coolant ejection manifold hole 115 and the outlet grooves 137A , and is on the low surface Ya between the Auslassnuten 137A and the central section 131 arranged. The coolant sealing elements 157B enclose the coolant ejection manifold hole 115 , and are on the low surface Yb between the coolant discharge manifold hole 115 and the outlet grooves 137B arranged.

The coolant sealing element 157A thus overlaps an arrangement position of the Auslassnuten 137B , and the coolant sealing elements 157B those of the outlet grooves 137A ,

In the following, the flow of fuel gas, oxidizing gas and refrigerant in such a fuel cell stack will be explained.

That of the fuel gas supply port 101 Fuel gas flowing into the fuel gas supply manifold passes through the fuel gas channels 139A on the central section 131 of the anode separator 130A are trained; it then flows into the refrigerant discharge manifold before leaving the fuel gas discharge port 104 is ejected. The fuel gas becomes the catalyst electrode of the MEA 121 supplied by the fuel gas channels 139A passes; It thus contributes to the generation of electricity in fuel cells.

That of the oxidizing gas supply port 103 Fuel gas flowing into the oxidizing gas supply manifold passes through the oxidizing gas passages 139B on the central section 131B of the cathode separator 130B are trained; it then flows into the refrigerant discharge manifold before leaving the oxidant gas discharge port 106 is ejected. The oxidizing gas becomes the catalyst electrode of the MEA 121 supplied by the oxidation gas channels 139B passes; It thus contributes to the generation of electricity in fuel cells.

That from the coolant supply port 102 Coolant flowing into the coolant supply manifold passes through the coolant inlet channels 143 and then flows into the coolant channels. The coolant extracts heat from the fuel cells as it passes through the coolant channels; it flows past via the coolant ejection channels 145 into the coolant discharge manifold.

Industrial Applicability

The inventive pair of sealing elements integrated with the separator is highly reliable seals so that it controls the flow of gas or refrigerant and prevents mutual mixing safely. Further, the fuel cell stack of the present invention is used in portable power supplies, electric power supplies of automobiles, and home power-heat coupling systems.

LIST OF REFERENCE NUMBERS

100

fuel cell stack

101

fuel gas supply opening

102

Kühlmittelzuführöffnung

103

Oxidationsgaszuführöffnung

104

Fuel gas discharge port

105

Coolant discharge port

106

Oxidizing gas discharge port

107

endplate

108

mounting bolts

109

mother

110

Brenngaszuführ distribution hole

111

Fuel gas discharge manifold hole

112

Oxidationsgaszuführ distribution hole

113

Oxidizing gas discharge manifold hole

114

Coolant supply manifold hole

115

Coolant discharge manifold hole

120

with frame integrated MEA

121

MEA

122

thinnest section of the frame

123

frame

124

deepening

125

Polymer electrolyte membrane

127

Catalyst electrode

130

Metal separators

131

central section

132

Reaction gas distribution section

133

Outer peripheral portion

135

inlet groove

137

exhaust groove

139

Reaction gas channel

140

of separators

141

Coolant channel

142

Coolant distribution sections

143

Coolant inlet channel

145

Coolant discharge passage

151

Outer peripheral sealing element

153

Fuel gas sealing element

155

Oxidizing gas sealing element

157

Coolant sealing element

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 2006-147258 A [0013]
• JP 2003-197221A [0013]
• JP 2004-63094 A [0013]
• JP 2007-329125 A [0013]

Claims (4)

A fuel cell stack in the frame-integrated MEAs each having an MEA and a frame enclosing the MEA and having a coolant supply manifold hole; and separator pairs wherein each of a metal separator A and a metal separator B each having a corrugated and channel-forming central portion and an outer peripheral portion enclosing the central portion are opposed to each other so as to bring the outer peripheral portions into contact with each other, and the metal separator A and the metal separator B has a coolant distribution hole disposed on the outer peripheral portion and coolant seal members disposed on the back surface of the contacting portion of the outer peripheral portion; stacked on each other, where the frame has the coolant sealing elements receiving recesses, the separator pair comprises coolant channels formed from opposing surfaces of the central portions of the metal separators A and B and a coolant inlet channel connecting the coolant channels and the coolant supply manifold hole; an upper part of the coolant inlet passage consists of an inlet groove A formed on an opposite surface of the outer peripheral portion of the metal separator A and communicating with the coolant supply manifold hole; a lower part of the coolant inlet passage consists of an inlet groove B formed on an opposite surface of the outer peripheral portion of the metal separator B and communicating with the central portion, a coolant seal member A disposed on the rear side of the contact portion of the outer peripheral portion of the metal separator A and enclosing the coolant supply manifold hole and the groove A, and a coolant seal member B disposed on the rear side of the contact portion of the outer peripheral portion of the metal separator B encloses the coolant supply manifold hole. The fuel cell stack according to claim 1, wherein the area surrounded by the refrigerant seal member A includes that surrounded by the refrigerant seal member B, and the refrigerant seal member A and the coolant seal member B do not overlap. The fuel cell stack according to claim 1, wherein the outer peripheral portion further comprises a coolant discharge manifold hole, wherein the separator pair further includes a refrigerant discharge passage connecting the refrigerant passages and the refrigerant discharge distribution hole; an upper part of the coolant inlet passage consists of an outlet groove B formed on the opposite curse of the outer peripheral portion of the metal separator B and communicating with the central portion, and a lower part of the coolant inlet passage consists of an exhaust groove A formed on the opposite surface of the outer peripheral portion of the metal separator A and communicating with the metal separator A and metal separators. The fuel cell stack of claim 1, wherein the metal separator A is an anode separator and the metal separator B is a cathode separator.

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