JP2006172752A - Polymer electrolyte fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-cost polymer electrolyte fuel cell by limiting the use of an expensive conductive material such as carbon to a minimum necessary part. <P>SOLUTION: In a separator of this application, a central part in a range including an electrode of a membrane-electrode conjugate including a frame body sandwiching the peripheral part of an electrolyte film is formed of a conductor such as a metal or carbon, and the peripheral part is formed of resin molded integrally with the conductor. Alternatively, it is formed of a conductor having a size to be combined with the inner edge of the frame body of the membrane-electrode conjugate. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an improvement in a separator of a solid polymer electrolyte fuel cell, and more particularly, to an improvement in a seal structure between a gasket and a conductive separator disposed on a peripheral portion of an electrolyte membrane-electrode assembly.

The most typical solid polymer electrolyte fuel cell includes a polymer electrolyte membrane supported by a gasket having a peripheral edge made of a sealing material, an anode joined to one surface of the electrolyte membrane, and the other of the electrolyte membrane. An electrolyte membrane-electrode assembly (MEA) composed of a cathode joined to the surface of the electrode, an anode-side conductive separator sandwiching the MEA, and a cathode-side conductive separator. The conductive separator has fluid supply means for supplying fuel and oxidant gas to the anode and the cathode, respectively. Separators are usually composed of carbon materials such as glassy carbon and expanded graphite because they must have high conductivity, high airtightness against reactive gases, and high corrosion resistance against reactions when hydrogen and oxygen are oxidized and reduced. (For example, see Patent Document 1).
JP 2003-77495 A

  The separator usually has a manifold hole in the vicinity of the peripheral edge and a fluid flow path in the center. Therefore, in order to ensure airtightness, the peripheral portion of the separator is not necessarily electrically conductive, but it is an expensive and poorly workable carbon material integrally with the portion forming the fluid flow path in the central portion. It is formed with. For this reason, it has become an obstacle to cost reduction of the solid polymer electrolyte fuel cell. Development of inexpensive metal separators with good workability has been underway, but the problem of corrosion has not yet been solved because the vicinity of the polymer film is a strongly acidic atmosphere.

  Therefore, an object of the present invention is to provide a low-cost solid polymer electrolyte fuel cell by limiting the use of a conductive material such as expensive carbon to the minimum necessary part.

The present invention includes (1) a polymer electrolyte membrane, a frame sandwiching a peripheral portion of the polymer electrolyte membrane, an anode bonded to one surface of the polymer electrolyte membrane, and the other surface of the polymer electrolyte membrane. And (2) a polymer electrolyte fuel cell comprising an anode separator and a cathode separator sandwiching the membrane electrode assembly.
In the separator of the present invention, the central part of the range including the electrode of the membrane electrode assembly is composed of a conductor such as metal or carbon, and the peripheral part is composed of a resin molded integrally with the conductor, Or it is comprised from the conductor of the magnitude | size combined with the inner edge part of the frame of a membrane electrode assembly.

  According to the present invention, since an expensive conductive material such as carbon is used only for the portion including the electrode, a low-cost fuel cell can be manufactured.

A polymer electrolyte fuel cell according to a first aspect of the present invention includes a cell stack in which a plurality of unit cells are stacked,
The unit cell includes (1) a polymer electrolyte membrane, a frame that sandwiches a peripheral portion of the polymer electrolyte membrane, an anode joined to one surface of the polymer electrolyte membrane, and the other of the polymer electrolyte membranes A membrane electrode assembly composed of a cathode joined to a surface, and (2) an anode side separator and a cathode side separator sandwiching the membrane electrode assembly,
The frame body of the membrane electrode assembly, and the anode side separator and the cathode side separator each have a pair of manifold holes for an oxidant gas and a fuel, and between the membrane electrode assembly and the anode side separator and the cathode side separator. Includes a fluid flow path that connects to the manifold holes of the pair of fuels and supplies fuel to the anode and a fluid flow path that connects to the manifold holes of the pair of oxidant gases and supplies oxidant gas to the cathodes.
And the said center part of the range which includes the said electrode is comprised with the conductor, and the peripheral part is comprised with the resin shape | molded integrally with the said conductor.

  In the polymer electrolyte fuel cell according to the first embodiment, the frame and the peripheral portions of the anode-side separator and the cathode-side separator are in surface contact with each other and the adjacent anode-side separator of the unit cell under compression of the cell stack. And the cathode separator are in surface contact with each other, the seal member provided on the frame body is deformed in the stacking direction, and the fluid circulation portion including the manifold hole and the fluid channel is hermetically isolated from the outside. It is preferable.

  In the fuel cell according to the first aspect, the frame body, the anode-side separator, and the cathode-side separator each have a pair of cooling water manifold holes between the anode-side separator and the cathode-side separator of adjacent single cells. A cooling water flow path connected to the cooling water manifold hole, and under compression of the cell stack, a seal member provided between the two separators is deformed in the stacking direction so that the cooling water manifold It is preferable to have a configuration in which the circulating portion of the cooling water including the holes and the cooling water flow path is liquid-tightly isolated from the outside.

A polymer electrolyte fuel cell according to a second aspect of the present invention is a polymer electrolyte fuel cell comprising a cell stack in which a plurality of unit cells are stacked,
The unit cell includes (1) a polymer electrolyte membrane, a frame that sandwiches a peripheral portion of the polymer electrolyte membrane, an anode joined to one surface of the polymer electrolyte membrane, and the other of the polymer electrolyte membranes A membrane electrode assembly composed of a cathode bonded to the surface, and (2) an outer peripheral edge portion that is in contact with the inner edge portion on the anode side and the inner edge portion on the cathode side of the frame body of the membrane electrode assembly. The anode-side conductive separator and the cathode-side conductive separator are in surface contact with the anode and the cathode, respectively.
The frame of the membrane electrode assembly has a pair of manifold holes for oxidant gas and fuel, and the frame and anode-side conductive separator are connected to the pair of fuel manifold holes and fuel to the anode. A fluid flow path is formed in the frame and the cathode-side conductive separator to connect the pair of oxidant gas manifold holes to supply the oxidant gas to the cathode.
Then, under compression of the cell stack, the frame members are in surface contact with each other, and the anode-side conductive separator and the cathode conductive-side separator of the adjacent unit cell are in surface contact, and a seal member provided on the frame body By deforming in the stacking direction, the fluid circulation portion including the manifold hole and the fluid flow path is airtightly isolated from the outside.
The sealing member preferably includes at least a cathode side sealing member and an anode side sealing member. That is, the cathode-side seal member surrounds the flow path of the oxidant gas that is formed over the frame and the cathode-side conductive separator and supplies the oxidant gas to the cathode from the pair of oxidant gas manifold holes. Formed. The anode-side seal member is formed so as to surround a fuel flow path that supplies fuel to the anode from a pair of fuel manifold holes formed across the frame and the anode-side conductive separator. Under the compression of the cell stack, these seal members are compressed by the adjacent frame body and frame body in the vicinity of the manifold hole, and are compressed by the frame body and the conductive separator in the portion surrounding the cathode or anode.

  In the fuel cell according to the second aspect, the frame body has a pair of cooling water manifold holes, and the cooling water is interposed between the anode side conductive separator and the cathode side conductive separator of the adjacent unit cell. A cooling water flow path connected to the manifold hole, and under compression of the cell stack, a seal member provided in the frame body is deformed in the stacking direction, whereby the cooling water manifold hole and the cooling water flow path It is preferable to have a configuration in which the circulating portion of the cooling water containing the liquid is isolated from the outside in a liquid-tight manner.

A polymer electrolyte fuel cell according to a third aspect of the present invention is a polymer electrolyte fuel cell comprising a cell stack in which a plurality of single cells are stacked,
The unit cell includes (1) a polymer electrolyte membrane, a frame that sandwiches a peripheral portion of the polymer electrolyte membrane, an anode joined to one surface of the polymer electrolyte membrane, and the other of the polymer electrolyte membranes A membrane electrode assembly composed of a cathode joined to the surface, and (2) a first seal member on each of the inner peripheral surface portion on the anode side and the inner peripheral surface portion on the cathode side of the frame body of the membrane electrode assembly. It has an outer peripheral surface part to be contacted, and consists of an anode side conductive separator and a cathode side conductive separator which are in surface contact with the anode and the cathode, respectively.
The frame of the membrane electrode assembly has a pair of manifold holes for oxidant gas and fuel, and the frame and anode-side conductive separator are connected to the pair of fuel manifold holes and fuel to the anode. A fluid flow path is formed in the frame and the cathode-side conductive separator to connect the pair of oxidant gas manifold holes to supply the oxidant gas to the cathode.
Then, under compression of the cell stack, the frames are in surface contact with each other, and the anode side conductive separator and the cathode conductive side separator of the adjacent unit cell are in surface contact, and the first seal member is in the stacking direction. By deforming in a vertical direction, the fluid flow path portion is airtightly isolated from the outside at a connection portion between the inner peripheral surface portion of the frame body and the outer peripheral surface portions of the anode side conductive separator and the cathode side conductive separator. The

  Further, the frame has a second seal member, and the second seal member is deformed in the stacking direction of the cell stack under compression of the cell stack, and cooperates with the seal member to form the manifold hole. In addition, the fluid circulation portion including the fluid flow path is configured to be airtightly isolated from the outside.

  In the fuel cell of the third embodiment, the frame body has a pair of cooling water manifold holes, and the cooling water is interposed between the anode side conductive separator and the cathode side conductive separator of the adjacent unit cell. A cooling water flow path connected to the manifold hole; and under compression of the cell stack, a third seal member provided in the frame body is deformed in the stacking direction, and cooperates with the seal member to It is preferable that the cooling water circulation portion including the water manifold hole and the cooling water flow path be separated from the outside in a liquid-tight manner.

The fuel cell of the fourth form is
(1) A polymer electrolyte membrane, a frame sandwiching a peripheral edge of the polymer electrolyte membrane, an anode joined to one surface of the polymer electrolyte membrane, and joined to the other surface of the polymer electrolyte membrane A membrane electrode assembly comprising a cathode, and (2) an anode side separator and a cathode side separator sandwiching the membrane electrode assembly,
The frame body of the membrane electrode assembly, and the anode side separator and the cathode side separator each have a pair of manifold holes for an oxidant gas and a fuel, and between the membrane electrode assembly and the anode side separator and the cathode side separator. Each having a fluid flow path for supplying fuel to the anode connected to the pair of fuel manifold holes and a fluid flow path for supplying oxidant gas to the cathode connected to the manifold holes for the pair of oxidant gases. A molecular electrolyte fuel cell,
In the separator, the central part of the range including the electrodes is made of a conductor, and the peripheral part is made of a resin molded integrally with the conductor.

The separator of the present invention and the conductive separator are made of a carbon material such as glassy carbon or expanded graphite having high conductivity, high hermeticity against a reactive gas, and high corrosion resistance against a hydrogen / oxygen oxidation-reduction reaction. Is preferred. The frame of the membrane electrode assembly and the peripheral portion of the separator having a conductor at the center are preferably a resin material for molding, and the seal member is preferably an elastomer or a synthetic resin having elasticity.
Hereinafter, embodiments of the present invention will be described in detail. In the following embodiments, the description will be made on the assumption that a gas such as hydrogen is used as the fuel. However, it goes without saying that the present invention can also be applied to a fuel using a liquid fuel such as a direct methanol fuel cell using an aqueous methanol solution.

Embodiment 1
A fuel cell according to Embodiment 1 will be described with reference to FIGS.
First, the membrane electrode assembly will be described. 1 is a front view of the cathode side of the membrane electrode assembly, FIG. 2 is a rear view thereof, a front view of the anode side, and FIG. 3 is an enlarged sectional view taken along line 3-3 of FIG.
The membrane electrode assembly 10 includes a polymer electrolyte membrane 1, a frame 11 integrally covering the peripheral edge of the membrane 1, a cathode 2 joined to one surface of the membrane, and an anode 3 joined to the other surface of the membrane. Consists of As shown in WO 02/061869, the frame 11 is integrally bonded to the peripheral portion of the electrolyte membrane 1 by injection molding a thermoplastic resin. It is preferable that a large number of through holes are provided in the peripheral portion of the membrane, and a portion covering one surface of the membrane and a portion covering the other surface are connected through the through holes.

The frame 11 has a pair of oxidant gas manifold holes 12, a fuel gas manifold hole 13, and a cooling water manifold hole 14. One of the pair of manifold holes is an inlet side, and the other is an outlet side. Further, the frame body 11 has four holes 15 through which fastening bolts are passed.
The frame 11 has a gas passage 18 communicating with the oxidant gas manifold hole 12 and the cathode on the surface where the cathode is located. The passage 18 is composed of five grooves formed on the frame body 11. The frame 11 further has a seal member 24 surrounding the manifold hole 13 for the fuel gas and a seal member 26 surrounding the manifold hole 14 for the cooling water on the surface where the cathode is located. The seal member 22 for preventing leakage of the oxidant gas surrounds the manifold hole 12 and the gas passage 18 connecting the cathode and the manifold hole 12 and the cathode 2 from the frame 11 to the surface of the electrolyte membrane 1. Has been placed. Since there is a step between the surface of the frame body 11 and the surface of the film 1, an inclined portion 16 is provided on the inner peripheral portion of the frame body 11 so as to protrude from the frame body onto the film 1. In the seal member 22, the part on the frame body and the part on the film 1 are connected.

The frame 11 has a seal member 25 surrounding the manifold hole 12 for the oxidizing gas and a seal member 27 surrounding the manifold hole 14 for the cooling water on the surface where the anode is located. The seal member 23 for preventing leakage of the fuel gas is disposed so as to surround the manifold hole 13, the gas passage 19 that connects the anode and the manifold hole 13, and the anode 3 from the frame 11 to the surface of the electrolyte membrane 1. Has been. The passage 19 is composed of three grooves formed on the frame 11. Since there is a step between the surface of the frame body 11 and the surface of the film 1, an inclined portion 17 is provided on the inner peripheral portion of the frame body 11 so as to protrude from the frame body onto the film 1. The seal member 23 is connected to a portion on the frame body and a portion on the membrane 1.
The sealing members 24, 26, 23, and 27 are integrally coupled to the frame body 11 by forming a sealing material so that a part thereof is embedded in a groove provided in the frame body 11. In addition, the sealing members 22 and 23 are integrated with the frame body by molding a sealing material so that a part in contact with the frame body 11 is embedded in a groove provided in the frame body 11 in the same manner as described above. Combined. The seal members 22 and 23 are formed on the electrolyte membrane so that the seal members are connected to each other through the through holes provided in the electrolyte membrane where there are corresponding portions on the front and back of the electrolyte membrane. Is fixed to the electrolyte membrane.

  4 is a front view of the anode separator, and FIG. 5 is an enlarged sectional view taken along line 5-5 of FIG. The anode-side separator 30 is composed of a central part 50 made of a conductor and a frame body 31 made of resin integrally formed on the peripheral part thereof. In this example, the frame body 31 is formed so as to cover the thin portion 52 provided at the peripheral portion of the central portion 50. Similar to the frame body 11, the frame body 31 has a pair of oxidant gas manifold holes 32, a fuel gas manifold hole 33, a cooling water manifold hole 34, and four holes 35 through which fastening bolts are passed. .

  The conductor 50 has a convex portion 51 sized to fit in the inner peripheral portion of the frame 11 on the surface facing the anode, and the surface of the fuel gas composed of three parallel grooves on the surface thereof. A flow path 53 is provided. The conductor 50 further has a recess 56 that fits the inclined portion 17 provided in the joined body 10 on the surface facing the anode. The anode separator 30 has a flat back surface extending from the frame 31 to the conductor 50.

Next, the cathode separator will be described with reference to FIGS.
6 is a perspective view of the cathode side separator, FIG. 7 is a front view of the cathode side separator, FIG. 8 is a rear view, and FIG. 9 is an enlarged sectional view taken along line 9-9 of FIG.
The cathode-side separator 40 is composed of a central portion 60 made of a conductor and a frame body 41 made of a resin that is molded integrally with the peripheral portion thereof. In this example, the frame body 41 is formed so as to cover the thin portion 63 provided at the peripheral edge of the central portion 60. Similar to the frame body 11, the frame body 41 has a pair of oxidant gas manifold holes 42, a fuel gas manifold hole 43, a cooling water manifold hole 44, and four holes 45 passing through fastening bolts. .

The conductor 60 has a convex portion 61 sized to fit in the inner peripheral portion of the frame 11 on the surface facing the cathode, and an oxidant gas composed of five parallel grooves on the surface thereof. The flow path 62 is provided. The conductor 60 further has a recess 66 that fits the inclined portion 16 provided in the joined body 10 on the surface facing the cathode. The back surface of the cathode-side separator 40 is flat from the frame body 41 to the conductor 60. The cathode separator 40 has a cooling water flow path 64 communicating with the pair of cooling water manifold holes 44 on the flat back surface. The flow path 64 is composed of five parallel grooves. The cathode separator 40 further includes a seal member 72 surrounding the manifold hole 42 for the oxidant gas, a seal member 73 surrounding the manifold hole 43 for the fuel gas, and a seal member surrounding the manifold hole 44 and the coolant flow path 64 on the back surface. 74.
The sealing members 72, 73, and 74 are integrally coupled to the separator 40 by molding a sealing material so that a part is embedded in a groove provided in the separator 40. When the center part 60 is produced by molding of a carbon material among the separators, the groove for the sealing material is formed at the time of molding. When the center part 60 is produced by cutting a carbon plate, the groove for the sealing material is formed by cutting.

FIG. 10 shows a cross-sectional view of the main part of a unit cell configured by combining the membrane electrode assembly 10, the anode side separator 30 and the cathode side separator 40. FIG. 10 is an enlarged cross-sectional view of the unit cell cut along a portion corresponding to line 5-5 in FIG.
The membrane electrode assembly 10 and the separators 30 and 40 are pressed in the stacking direction by a fastening pressure for fastening a cell stack in which a plurality of unit cells are stacked, and accordingly, each seal member is compressed in the stacking direction, and fuel gas, oxidation The agent gas and cooling water are prevented from leaking to the outside. That is, the cell stack is sandwiched between end plates via, for example, a current collector plate and an insulating plate, and fastening pressure is applied by fastening the end plates together. When the fuel cell is constituted by one single cell, the fastening is performed in the same manner. A sealing mechanism that prevents the fuel gas, the oxidant gas, and the cooling water from leaking to the outside will be described below.

  That is, between the membrane electrode assembly 10 and the anode-side separator 30, the fuel gas supplied from the inlet-side manifold holes 13 and 33 passes through one gas passage 19 of the assembly 10 and flows through the separator 30. The excess gas is supplied from 53 to the anode 3, and excess gas is discharged from the other gas passage 19 of the joined body 10 to the manifold holes 13 and 33 on the outlet side. The fuel gas flowing as above is compressed between the seal member 23 provided in the joined body 10 and the separator 30, and leakage to the outside is prevented. Further, the oxidant gas and the cooling water are compressed between the separators 30 and the sealing members 25 and 27 provided in the joined body 10, and the manifold holes 12 and 32 for the oxidant gas and the manifold holes 14 and 34 for the cooling water. Leakage from the outside is prevented.

  Between the membrane electrode assembly 10 and the cathode separator 40, the oxidant gas supplied from the manifold holes 12 and 42 on the inlet side passes through one gas passage 18 of the assembly 10 and the gas flow path of the separator 40. The excess gas and reaction product are supplied from 62 to the cathode 2, and are discharged from the other gas passage 18 of the joined body 10 to the manifold holes 12 and 42 on the outlet side. The oxidant gas flowing as above is compressed between the seal member 22 provided in the joined body 10 and the separator 40, and leakage to the outside is prevented. The fuel gas and the cooling water are compressed between the separators 40 and the seal members 24 and 26 provided in the joined body 10, and the fuel gas manifold holes 13 and 43 and the cooling water manifold holes 14 and 44 are externally provided. Leakage is prevented.

  In addition, between the anode-side separator 30 and the cathode-side separator 40 of the adjacent unit cells, the cooling water supplied from the inlet-side manifold holes 34 and 44 passes through the flow path 64 of the separator 40 in the process. The single cells are cooled from the back surfaces of 30 and 40 and discharged from the outlet side manifold holes 34 and 44. The cooling water flowing as above is compressed between the sealing member 74 provided in the separator 40 and the separator 30, and leakage to the outside is prevented. Further, the fuel gas and the oxidant gas are compressed between the separator members 30 and 72 provided in the separator 40 and the separator 30, and from the fuel gas manifold holes 33 and 43 and the oxidant gas manifold holes 32 and 42. Leakage to the outside is prevented.

  In the separator according to the present embodiment, the central portion including the electrode is formed of a carbon material such as glassy carbon or expanded graphite having excellent conductivity, airtightness, and corrosion resistance, and the peripheral portion is airtight and corrosion resistant. However, it is made of a moldable resin material that is not necessarily conductive, and a manifold hole is formed in the peripheral portion. With such a configuration, the amount of carbon used can be greatly reduced, and a low-cost polymer electrolyte fuel cell can be provided.

Embodiment 2
A fuel cell according to Embodiment 2 will be described with reference to FIGS.
First, the membrane electrode assembly will be described. 11 is a front view of the membrane electrode assembly on the cathode side, FIG. 12 is a rear view thereof, a front view of the anode side, and FIG. 13 is an enlarged sectional view taken along line 13-13 in FIG.

  The membrane electrode assembly 110 includes a polymer electrolyte membrane 1, a frame body 111 integrally covering the peripheral edge of the membrane 1, a cathode 2 joined to one surface of the membrane, and an anode 3 joined to the other surface of the membrane. Consists of As in the first embodiment, the frame body 111 is integrally joined to the peripheral edge portion of the electrolyte membrane 1 by injection molding a thermoplastic resin.

The frame 111 has a pair of oxidant gas manifold holes 112, a fuel gas manifold hole 113, and a cooling water manifold hole 114. Further, the frame body 111 has four holes 115 through which fastening bolts are passed.
The frame 111 has a gas passage 118 that communicates between the manifold hole 112 for the oxidant gas and the cathode on the surface where the cathode is located. The passage 118 is composed of five grooves. The frame 111 further has a seal member 124 that partially surrounds the fuel gas manifold hole 113 and a seal member 126 that partially surrounds the cooling water manifold hole 114 on the surface where the cathode is located. The seal member for preventing leakage of the oxidant gas corresponds to the passage 118 on the frame 111 and the seal member 122a surrounding the portion extending from the manifold hole 112 to the gas passage 118 connecting the cathode and the manifold hole 112. The seal member 122b is arranged so as to surround the cathode 2 except for the portion.

The frame body 111 has a step portion 128 that is one step lower on the inner edge portion, and the seal member 122 b is provided on the step portion 128. The seal members 122a and 122b are connected on an inclined portion 116c provided so as to protrude on the step portion 128.
The seal members 122 a, 124 and 126 are connected to each other on the frame body 111. Further, the end portion of the seal member 124 extends to a desired portion of the stepped portion 128 so as to partition a portion 183 that becomes a fuel gas passage to be described later. The end of the seal member 126 surrounds the cooling water flow path 184 and is connected to the seal member 122b on the stepped portion 128. The step portion 128 is provided with an inclined portion 116 w for guiding the end portion of the seal member 126.

  The frame 111 has, on the surface on the side where the anode is located, a projecting portion 121 that is one step higher on the inner peripheral portion and a lower step portion 129 on the inner side. On this step part 129, the sealing member 123 surrounding the anode is provided. The end of the seal member 123 ends at an inclined portion 117 on the step portion 129 on both sides of the gas passage 119 connecting the manifold hole 113 and the anode 3. The gas passage 119 is composed of three grooves having a bottom surface at the same level as the step portion 129.

  14 is a front view of the anode separator, and FIG. 15 is an enlarged cross-sectional view taken along line 15-15 of FIG. The anode separator 130 is made of a conductor, and has a size that fits on the inner peripheral surface of the protrusion 121 on the step portion 129 of the frame body 111. The separator 130 has a surface facing the anode, which includes a peripheral portion 131 that is placed on the step portion of the frame body 111, and a convex portion 132 that is one step larger in size to be loosely fitted to the inner peripheral portion of the frame body 111. Yes. On the surface of the convex portion 132, there is a fuel gas flow path 153 composed of three parallel grooves. The peripheral portion 131 has a concave portion 156 into which the inclined portion 117 of the frame body 111 is fitted. The anode side separator 130 has a flat back surface.

Next, the cathode side separator will be described with reference to FIGS.
16 is a front view of the cathode separator, FIG. 17 is a rear view, and FIG. 18 is an enlarged sectional view taken along line 18-18 of FIG.

  The cathode-side separator 140 is made of a conductor and has a size that fits on the stepped portion 128 of the frame body 111. The separator 140 includes a peripheral surface 141 that faces the cathode on the step portion 128 of the frame body 111, and a convex portion 142 that is one step larger in size to fit loosely into the inner peripheral portion of the frame body 111. ing. On the surface of the convex portion 142, there is an oxidant gas flow path 162 composed of five parallel grooves. The peripheral portion 141 has concave portions 166c and 166w into which the inclined portions 116c and 116w of the frame body 111 are fitted, respectively. The cathode side separator 140 has a cooling water flow path 164 composed of five parallel grooves on the back surface.

  FIG. 19 shows a cross-sectional view of the main part of a unit cell configured by combining the membrane electrode assembly 110, the anode side separator 130 and the cathode side separator 140 described above. FIG. 19 is an enlarged cross-sectional view of the unit cell cut along a portion corresponding to line 19-19 in FIG.

  A unit cell is constituted by the joined body 110 and the anode-side separator 130 and the cathode-side separator 140 that are combined at the center of the anode side and the cathode side. And by the fastening pressure which fastens the cell stack which laminated | stacked the single cell, each seal member is compressed in the lamination direction, and it is prevented that fuel gas, oxidizing agent gas, and cooling water leak outside.

  That is, the fuel gas supplied from the manifold hole 113 on the inlet side of the joined body 110 is supplied to the anode 3 from the fluid flow path 153 of the separator 130 via one gas passage 119 of the joined body 110, and the surplus gas is supplied to the joined body. 110 is discharged from the other gas passage 119 to the manifold hole 113 on the outlet side. The fuel gas flowing as described above is compressed between the adjacent bonded body 110 and the sealing member 124 provided on the bonded body 110, and the sealing member 123 on the step portion 129 of the frame body 111 is the peripheral edge of the separator 130. Compressed with the unit 131 to prevent leakage to the outside.

  The oxidant gas supplied from the inlet-side manifold hole 112 of the joined body 110 is supplied to the cathode from the flow path 162 of the separator 140 via one gas passage 118 of the joined body 110, and the surplus gas and the reaction product are supplied to the joined body. 110 is discharged from the other gas passage 118 of 110 to the manifold hole 112 on the outlet side. The seal member 122a is compressed between the adjacent joined bodies. Further, the seal member 122b is compressed between the peripheral edge portion 141 of the cathode side separator 140. Thus, leakage of the oxidant gas to the outside is prevented.

  Next, a cooling water flow path 164 is formed between the anode-side separator 130 and the cathode-side separator 140 of the adjacent unit cells. The cooling water supplied from the inlet side manifold hole 114 of the joined body 110 enters the flow path 164 from one passage 184 of the cooling water, and is discharged from the other passage 184 to the manifold hole 114 on the outlet side. The passage 184 is composed of five grooves. The cooling water flowing in this way is compressed between the seal member 126 of the joined body 110 and the adjacent joined body in a portion extending from the manifold hole 114 to the passage 184, and leakage to the outside is prevented. On the stepped portion 128 of the joined body 110, the seal member 122b is compressed between the separator 140 and the cooling water does not enter the cathode side of the separator 140. Similarly, since the seal member 123 on the step portion 129 of the joined body 110 is compressed between the separator 130, the cooling water does not enter the anode side of the separator 130.

  In this Embodiment, a conductive separator is a magnitude | size including an electrode part, and is combined with the center of the frame of a membrane electrode assembly. Therefore, the amount of carbon material used can be greatly reduced. In addition, since the process relating to resin integral molding of the conductive separator portion and its frame body in Embodiment 1 is not required, a further low-cost polymer electrolyte fuel cell can be provided.

Embodiment 3
A fuel cell according to Embodiment 3 will be described with reference to FIGS.
First, the membrane electrode assembly will be described. 20 is a front view on the cathode side of the membrane electrode assembly, FIG. 21 is a rear view thereof, a front view on the anode side, and FIG. 22 is an enlarged sectional view taken along line 22-22 of FIG.

  The membrane electrode assembly 210 includes a polymer electrolyte membrane 1, a frame body 211 integrally covering the peripheral edge of the membrane 1, a cathode 2 joined to one surface of the membrane, and an anode 3 joined to the other surface of the membrane. Consists of Similar to the first embodiment, the frame body 211 is integrally bonded to the peripheral edge portion of the electrolyte membrane 1 by injection molding a thermoplastic resin.

The frame 211 has a pair of oxidant gas manifold holes 212, a fuel gas manifold hole 213, and a cooling water manifold hole 214. Further, the frame body 211 has four holes 215 through which fastening bolts are passed.
The frame 211 has a gas passage 218 communicating with the oxidant gas manifold hole 212 and the cathode on the surface where the cathode is located. The passage 218 is composed of five grooves. The frame 211 further has a seal member 224 that partially surrounds the fuel gas manifold hole 213 and a seal member 226 that partially surrounds the cooling water manifold hole 214 on the surface where the cathode is located. The seal member for preventing leakage of the oxidant gas includes a seal member 222a surrounding a portion extending from the manifold hole 212 to the gas passage 218 connecting the manifold hole 212 and the cathode on the frame 211, and the inside of the frame 211. On the peripheral surface, the seal member 222b is arranged so as to surround the cathode 2 except for the portion corresponding to the gas passage. Seal members 222a and 222b are connected on the inner peripheral surface of the frame.

  The seal members 222a, 224 and 226 are connected to each other on the frame 211. Further, the end portion of the seal member 224 extends to the seal member 222b so as to define a portion 283 serving as a fuel gas passage, which will be described later, and is connected thereto. The end of the seal member 226 surrounds the cooling water flow path 284 and is connected to the seal member 222b. The flow path 284 is composed of five grooves.

  The frame 211 has a protrusion 221 that is one step higher on the inner peripheral portion on the surface on which the anode is located. A seal member 223 surrounding the anode is provided on the inner peripheral surface of the frame 211 except for the portion corresponding to the fuel gas passage 219. The passage 219 is composed of three grooves.

  FIG. 23 is a front view of the anode separator. The anode-side separator 230 is made of a conductor and has a size to be fitted to the inner peripheral surface of the frame body 211 via the seal member 223. The separator 230 has a fuel gas flow path 253 formed of three parallel grooves on the surface facing the anode. The anode separator 230 has a flat back surface.

Next, the cathode side separator will be described with reference to FIGS.
FIG. 24 is a front view of the cathode side separator, and FIG. 25 is a rear view.
The cathode-side separator 240 is made of a conductor and has a size that fits to the inner peripheral surface of the frame body 211 via the seal member 222b. The separator 240 has an oxidant gas flow path 262 composed of five parallel grooves on the surface facing the cathode. The separator 240 has a cooling water flow path 264 configured with five grooves parallel to the back surface.

  FIG. 26 shows a cross-sectional view of the main part of a unit cell configured by combining the membrane electrode assembly 210, the anode side separator 230, and the cathode side separator 240 described above. 26 is an enlarged cross-sectional view of the unit cell cut along a portion corresponding to line 26-26 in FIG.

  A unit cell is constituted by the joined body 210 and the anode-side separator 230 and the cathode-side separator 240 combined in the central part on the anode side and the cathode side thereof. Then, each sealing member is compressed in a stacking direction or a direction perpendicular thereto by a fastening pressure for fastening a cell stack in which a plurality of unit cells are stacked, and fuel gas, oxidant gas and cooling water leak to the outside. Is prevented.

  That is, the fuel gas supplied from the manifold hole 213 on one inlet side of the joined body 210 is supplied to the anode 3 from the flow path 253 of the separator 230 via the gas passage 219 of the joined body 210, and the surplus gas is supplied to the joined body 210. The other gas passage 219 is discharged to the outlet manifold hole 213. The fuel gas flowing above is compressed between the adjacent frame body 210 and the seal member 223 provided on the joined body 210, and the seal member 223 on the inner peripheral surface of the frame body 210 is the outer peripheral surface of the separator 230. , And leakage to the outside is prevented.

  The oxidant gas supplied from the inlet side manifold hole 212 of the joined body 210 is supplied to the cathode from the flow path 262 of the separator 240 through one gas passage 218 of the joined body 210, and the surplus gas and the reaction product are supplied to the joined body. The gas is discharged from the other gas passage 218 of 210 to the manifold hole 212 on the outlet side. The seal member 222a surrounding the portion extending from the manifold hole 212 to the gas passage 218 is compressed between the adjacent joined bodies. Further, the seal member 222b is compressed between the outer peripheral surface of the cathode-side separator 240. Thus, leakage of the oxidant gas to the outside is prevented.

  Next, a cooling water flow path 264 is formed between the anode-side separator 230 and the cathode-side separator 240 of the adjacent unit cells. The cooling water supplied from the inlet side manifold hole 214 of the joined body 210 enters the flow path 264 of the separator 240 from one passage 284 of the cooling water, and exits from the other passage 284 of the joined body 210 to the outlet side manifold hole. It is discharged to 214. The cooling water flowing in this way is compressed between the sealing member 226 of the joined body 210 and the adjacent joined body in a portion extending from the manifold hole 214 to the passage 284, and leakage to the outside is prevented. On the inner peripheral surface of the frame 211, the seal member 222 b is compressed between the outer peripheral surface of the separator 240, so that cooling water does not enter the cathode side of the separator 240. Similarly, since the sealing member 223 on the inner peripheral surface of the frame 211 is compressed between the outer peripheral surface of the separator 230, the cooling water does not enter the anode side of the separator 230.

According to the present embodiment, a low-cost polymer electrolyte fuel cell can be provided as in the second embodiment. In addition, the sealing member between the frame and the conductive separator is deformed in a direction perpendicular to the stacking direction of the cell stack for sealing, so that the sealing member is integrally formed with the frame and sealed in the stacking direction. It has the advantage that no glue margin is required.
The manufacturing method of the seal member in the second and third embodiments is the same as the method described in the first embodiment.
In the above embodiments, the frame and the seal member have been described as separate parts, but they can also be manufactured using the same resin material such as a thermoplastic elastomer.

  Examples of the present invention will be described below.

Example 1
A polymer electrolyte membrane (Dupont Naphion 117, 50 μm thick) was punched into a 140 mm square shape using a Thomson mold. Using this polymer electrolyte membrane as an insert part, a frame having the structure shown in the first embodiment was formed using polypropylene (R250G manufactured by Idemitsu Petrochemical Co., Ltd.) to which glass fiber was added.

Next, platinum was supported in a ratio of 1: 1 by weight on Ketjen Black EC (furnace black manufactured by Ketjen Black International Co., Ltd.) having a specific surface area of 800 m ² / g and DBP oil absorption of 360 ml / 100 g. To 10 g of this catalyst powder, 35 g of water and 59 g of an alcohol dispersion of hydrogen ion conductive polymer electrolyte (9% FSS, manufactured by Asahi Glass Co., Ltd.) are mixed and dispersed using an ultrasonic stirrer. Produced. This catalyst layer ink was applied to a polypropylene film (Treffan 50-2500 manufactured by Toray Industries, Inc.) and dried to form a catalyst layer. The obtained catalyst layer was cut into 120 mm × 120 mm, and transferred to both the anode side and the cathode side of the exposed portion of the polymer electrolyte membrane of the molded article under the conditions of a temperature of 135 ° C. and a pressure of 32 kgf / cm ^2. Formed. A membrane electrode assembly is formed by combining a polymer electrolyte membrane joined with a catalyst layer with a 123 mm square gas diffusion layer (Carbell CF400 manufactured by Japan Gore-Tex Co., Ltd., thickness 400 μm) under a pressure of 20 kgf / cm ^2. Was made.

  As the conductor of the separator, glassy carbon (manufactured by Tokai Carbon Co., Ltd., thickness: 3 mm) was used as a material. Two types, one for the anode side and one for the cathode side, were manufactured, and the gas flow path, cooling water flow path, and the like were manufactured by cutting machining. Using these conductors as insert parts, polypropylene with glass fiber added to the peripheral edge thereof was molded to produce an anode side separator and a cathode side separator. These separators were provided with manifold holes and necessary gas and cooling water passages.

  The membrane electrode assembly according to Embodiment 1 manufactured as described above was sandwiched between the anode-side separator and the cathode-side separator to obtain a single cell. End plates are stacked on both ends of a cell stack in which 50 cells of such a single cell are stacked via a metal current collector plate and an insulating plate made of an electrically insulating material, and the end plates are fixed with a fastening rod. A fuel cell was prepared.

  A battery test was conducted by supplying hydrogen to the anode of the fuel cell and air to the cathode and circulating cooling water. The battery output under the conditions of a hydrogen utilization rate of 70%, an oxygen utilization rate of 20%, a hydrogen humidification bubbler temperature of 85 ° C., an oxygen humidification bubbler temperature of 75 ° C., and a battery temperature of 75 ° C. was 1050 W (30 A-35 V).

  According to the present invention, it is possible to manufacture a fuel cell having high gas sealing performance at low cost. This fuel cell is useful for cogeneration systems and electric vehicles.

1 is a front view of a cathode side of a membrane electrode assembly of a fuel cell according to Embodiment 1 of the present invention. It is a rear view of the membrane electrode assembly. FIG. 3 is an enlarged sectional view taken along line 3-3 in FIG. 2. It is a front view of an anode side separator. FIG. 5 is an enlarged sectional view taken along line 5-5 of FIG. It is a perspective view of a cathode side separator. It is a front view of a cathode side separator. It is a rear view of a cathode side separator. FIG. 9 is an enlarged cross-sectional view taken along line 9-9 in FIG. 7. It is an expanded sectional view of the principal part of a cell.

It is a front view by the side of the cathode of the membrane electrode assembly of the fuel cell which concerns on Embodiment 2 of this invention. It is a rear view of the membrane electrode assembly. It is a 13-13 line expanded sectional view of Drawing 11. It is a front view of an anode side separator. It is a 15-15 line expanded sectional view of FIG. It is a front view of a cathode side separator. It is a rear view of a cathode side separator. FIG. 18 is an enlarged cross-sectional view taken along line 18-18 in FIG. 16. It is an expanded sectional view of the principal part of a cell. It is a front view by the side of the cathode of the membrane electrode assembly of the fuel cell which concerns on Embodiment 3 of this invention.

It is a rear view of the membrane electrode assembly. It is a 22-22 line expanded sectional view of FIG. It is a front view of an anode side separator. It is a front view of a cathode side separator. It is a rear view of a cathode side separator. It is an expanded sectional view of the principal part of a cell.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrolyte membrane 2 Cathode 3 Anode 10 Membrane electrode assembly 11 Frame body 12, 32, 42 Manifold hole of oxidant gas 13, 33, 43 Manifold hole of fuel gas 14, 34, 44 Manifold hole 22, 23 of cooling water, 24, 25, 26, 27, 72, 73, 74 Seal member 30 Anode-side separator 31, 41 Peripheral portion 40 Cathode-side separator 50, 60 Conductor 53 Fuel gas flow path 62 Oxidant gas flow path 64 Cooling water Flow path

Claims (8)

A cell stack in which a plurality of single cells are stacked,
The unit cell includes (1) a polymer electrolyte membrane, a frame that sandwiches a peripheral portion of the polymer electrolyte membrane, an anode joined to one surface of the polymer electrolyte membrane, and the other of the polymer electrolyte membranes A membrane electrode assembly composed of a cathode joined to a surface, and (2) an anode side separator and a cathode side separator sandwiching the membrane electrode assembly,
The frame body of the membrane electrode assembly, and the anode side separator and the cathode side separator each have a pair of manifold holes for an oxidant gas and a fuel, and between the membrane electrode assembly and the anode side separator and the cathode side separator. Each having a fluid flow path for supplying fuel to the anode connected to the pair of fuel manifold holes and a fluid flow path for supplying oxidant gas to the cathode connected to the manifold holes for the pair of oxidant gases. A molecular electrolyte fuel cell,
The polymer electrolyte fuel cell according to claim 1, wherein a central portion of the separator including the electrode is made of a conductor, and a peripheral portion is made of a resin molded integrally with the conductor.   Under compression of the cell stack, the frame and the peripheral portions of the anode-side separator and the cathode-side separator are in surface contact, and the anode-side conductive separator and the cathode-conductive side separator of the adjacent unit cell are in surface contact, 2. The polymer electrolyte fuel cell according to claim 1, wherein a seal member provided on the frame body is deformed in the stacking direction so that a fluid circulation portion including the manifold hole and the fluid flow path is hermetically isolated from the outside.   Each of the frame body, the anode side separator, and the cathode side separator has a pair of cooling water manifold holes, and is connected to the cooling water manifold hole between the anode side separator and the cathode side separator of the adjacent unit cell. A cooling water flow path having a cooling water passage, and a seal member provided between the separators deforms in the stacking direction under compression of the cell stack, and includes a cooling water manifold hole and a cooling water flow path. The polymer electrolyte fuel cell according to claim 1 or 2, wherein a water circulation portion is separated from the outside in a liquid-tight manner. A polymer electrolyte fuel cell comprising a cell stack in which a plurality of unit cells are stacked,
The unit cell includes (1) a polymer electrolyte membrane, a frame that sandwiches a peripheral portion of the polymer electrolyte membrane, an anode joined to one surface of the polymer electrolyte membrane, and the other of the polymer electrolyte membranes A membrane electrode assembly composed of a cathode bonded to the surface, and (2) an outer peripheral edge portion that is in contact with the inner edge portion on the anode side and the inner edge portion on the cathode side of the frame body of the membrane electrode assembly. An anode side conductive separator and a cathode side conductive separator that are in surface contact with the anode and the cathode, respectively,
The frame of the membrane electrode assembly has a pair of manifold holes for oxidant gas and fuel, and the frame and anode-side conductive separator are connected to the pair of fuel manifold holes and fuel to the anode. A fluid flow path for supplying an oxidant gas to the cathode is formed in the frame body and the cathode side conductive separator connected to the pair of oxidant gas manifold holes,
Under compression of the cell stack, the frames are in surface contact with each other, the anode-side conductive separator and the cathode conductive-side separator of the adjacent unit cell are in surface contact, and the sealing member provided on the frame is stacked in the stacking direction. The polymer electrolyte fuel cell is characterized in that the fluid circulation portion including the manifold hole and the fluid flow path is hermetically isolated from the outside.   The frame has a pair of cooling water manifold holes, and a cooling water flow path connected to the cooling water manifold hole is provided between the anode side conductive separator and the cathode side conductive separator of the adjacent unit cell. And under the compression of the cell stack, a seal member provided on the frame body is deformed in the stacking direction, and a cooling water circulation part including the cooling water manifold hole and the cooling water flow path 5. The polymer electrolyte fuel cell according to claim 4, wherein the polymer electrolyte fuel cell has a structure that is liquid-tightly isolated. A polymer electrolyte fuel cell comprising a cell stack in which a plurality of unit cells are stacked,
The unit cell includes (1) a polymer electrolyte membrane, a frame that sandwiches a peripheral portion of the polymer electrolyte membrane, an anode joined to one surface of the polymer electrolyte membrane, and the other of the polymer electrolyte membranes A membrane electrode assembly composed of a cathode joined to the surface, and (2) a first seal member on each of the inner peripheral surface portion on the anode side and the inner peripheral surface portion on the cathode side of the frame body of the membrane electrode assembly. It has an outer peripheral surface part to be contacted, and consists of an anode side conductive separator and a cathode side conductive separator which are in surface contact with the anode and the cathode, respectively.
The frame of the membrane electrode assembly has a pair of manifold holes for oxidant gas and fuel, and the frame and anode-side conductive separator are connected to the pair of fuel manifold holes and fuel to the anode. A fluid flow path for supplying an oxidant gas to the cathode is formed in the frame body and the cathode side conductive separator connected to the pair of oxidant gas manifold holes,
Under compression of the cell stack, the frames are in surface contact with each other, and the anode side conductive separator and cathode conductive side separator of the adjacent unit cell are in surface contact, and the seal member is deformed in a direction perpendicular to the stacking direction. The fluid flow path portion is airtightly isolated from the outside at a connection portion between the inner peripheral surface portion of the frame body and the outer peripheral surface portion of the anode side conductive separator and the cathode side conductive separator,
Further, the frame body has a second seal member, and under the compression of the cell stack, the second seal member is deformed in the stacking direction of the cell stack and cooperates with the first seal member. A polymer electrolyte fuel cell in which a fluid circulation portion including the manifold hole and the fluid flow path is hermetically isolated from the outside.   The frame has a pair of cooling water manifold holes, and a cooling water flow path connected to the cooling water manifold hole is provided between the anode side conductive separator and the cathode side conductive separator of the adjacent unit cell. And a third seal member provided on the frame body is deformed in the stacking direction under compression of the cell stack, and cooperates with the seal member to form the cooling water manifold hole and the cooling water flow path. The polymer electrolyte fuel cell according to claim 6, wherein a circulating portion of the cooling water containing is isolated from the outside in a liquid-tight manner. (1) A polymer electrolyte membrane, a frame sandwiching a peripheral edge of the polymer electrolyte membrane, an anode joined to one surface of the polymer electrolyte membrane, and joined to the other surface of the polymer electrolyte membrane A membrane electrode assembly comprising a cathode, and (2) an anode side separator and a cathode side separator sandwiching the membrane electrode assembly,
The frame body of the membrane electrode assembly, and the anode side separator and the cathode side separator each have a pair of manifold holes for an oxidant gas and a fuel, and between the membrane electrode assembly and the anode side separator and the cathode side separator. Each having a fluid flow path for supplying fuel to the anode connected to the pair of fuel manifold holes and a fluid flow path for supplying oxidant gas to the cathode connected to the manifold holes for the pair of oxidant gases. A molecular electrolyte fuel cell,
The polymer electrolyte fuel cell according to claim 1, wherein a central portion of the separator including the electrode is made of a conductor, and a peripheral portion is made of a resin molded integrally with the conductor.

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