JP2011023161A - Sealing structure of fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To aim at reduction in lamination components and lamination processes by integrating a gasket and an anode-side and a cathode-side separators. <P>SOLUTION: Power-generating bodies 10 each having a membrane-electrode assembly 11 equipped with an anode and a cathode on either face of an electrolyte membrane, and separators 20 each having a gasket 30 integrated are alternately laminated in a thickness direction. The separator 20 has an anode-side plate 21 forming a reaction gas flow channel F1 against an anode side of the power-generating body 10 arranged at one side in a thickness direction and a cathode-side plate 22 forming a reaction gas flow channel F2 against a cathode side of the power-generating body 10 arranged at the other side as well as a coolant flow channel F3 against the anode-side plate 21 are integrally coupled with each other through a part (intermediate rubber-filling part) 36 of the gasket 30. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a sealing structure for allowing a fuel gas, an oxidant gas, a cooling medium and the like to flow through independent flow paths in a fuel cell.

  The fuel cell includes a sealing structure for allowing fuel gas, oxidant gas, cooling medium, and the like to flow through independent flow paths. FIG. 10 is a partial cross-sectional view showing a fuel cell sealing structure according to the prior art in an unstacked state, and FIG.

  10 and 11, reference numeral 110 denotes a gas diffusion made of a porous material on both sides in the thickness direction of a membrane-electrode assembly 111 made of an electrolyte membrane and catalyst electrode layers (anode and cathode) provided on both surfaces of the electrolyte membrane. A power generator in which layers 112 and 113 are laminated and integrated. And the fuel cell 100 is comprised by laminating | stacking the separators 120 and 130 which consist of carbon or an electroconductive metal on the thickness direction both sides of this electric power generation body 110. As shown in FIG.

  In each fuel cell 100, the outer peripheral portion of the membrane-electrode assembly 111 in the power generator 110 is a seal ridge formed integrally with one separator 120 with a rubber-like elastic material (rubber or a synthetic resin material having rubber-like elasticity). (Hereinafter referred to as anode seal protrusion for convenience) 121 and a seal protrusion (hereinafter referred to as cathode seal protrusion for convenience) 131 integrally formed with the other separator 130 with a rubber-like elastic material. The

  A fuel gas flow channel 100a is defined between the anode of the membrane-electrode assembly 111 and the one separator 120 facing the anode by the anode sealing protrusion 121, and the cathode of the membrane-electrode assembly 111. And the other separator 130 opposed thereto, an oxidant gas flow path 100b is defined by the cathode seal protrusion 131. In addition, a refrigerant seal protrusion 122 is integrally formed of a rubber-like elastic material on the surface of one separator 120 opposite to the seal protrusion 121, and the separators 120, 130 of the adjacent fuel cells 100, 100 are formed. In the meantime, the refrigerant flow path 100c is defined by the refrigerant seal protrusion 122.

  That is, in this type of fuel cell, in each fuel cell 100, the fuel gas flowing through the fuel gas channel 100a is supplied to the anode side of the membrane-electrode assembly 111 via the gas diffusion layer 112, and the oxidant gas Oxidant gas or fuel gas flowing through the flow channel 100b is supplied to the cathode side of the membrane-electrode assembly 111 through the gas diffusion layer 113, and the reverse reaction of water electrolysis, that is, water is generated from hydrogen and oxygen. Electric power is generated by the reaction. And although the electromotive force by each fuel cell 100 is low, a required electromotive force can be obtained by stacking a large number of fuel cells 100 and electrically connecting them in series (for example, Patent Document 1).

  However, according to the conventional fuel cell sealing structure, the anode seal projection 121 and the refrigerant seal projection 122 are integrally formed on one separator 120, and the cathode seal projection 131 is also formed on the other separator 130. There was a large number of parts because it was necessary to mold them integrally. When there are a large number of laminated parts, not only the number of assembling steps for stack assembly increases, but also there is a problem that the laminating error tends to increase due to the accumulation of slight positional deviations between the parts.

JP 2005-222708 A

  The present invention has been made in view of the above points, and its technical problem is to integrate a gasket, an anode-side separator, and a cathode-side separator in a fuel cell sealing structure. The purpose is to reduce the number of laminated parts and the number of lamination processes.

  As a means for effectively solving the above technical problem, a fuel cell sealing structure according to the invention of claim 1 includes a power generator having a membrane-electrode composite provided with an anode and a cathode on both sides of an electrolyte membrane, and The separators integrally provided with gaskets are alternately stacked in the thickness direction, and the separator forms a reaction gas flow path between the separator and the anode side of the power generator disposed on one side in the thickness direction. A cathode side plate that forms a reaction gas flow path between the anode side plate and the cathode side of the power generator disposed on the other side and forms a refrigerant flow path between the anode side plate and the gasket side of the gasket. They are integrally connected to each other through a part.

  According to a second aspect of the present invention, there is provided a fuel cell sealing structure according to the first aspect, wherein a gasket is brought into close contact with an outer peripheral portion of the power generator to thereby provide a reaction gas flow path on one side of the power generator. A first seal protrusion that defines a second gas flow path on the other side of the power generator by being in close contact with an adjacent gasket or separator outside the edge of the power generator. It has a refrigerant | coolant seal | sticker part which defines the refrigerant | coolant flow path of the inner peripheral side by interposing between a seal protrusion and the outer peripheral part of an anode side plate and a cathode side plate.

  According to a third aspect of the present invention, there is provided the fuel cell sealing structure according to the first aspect, wherein the anode side plate and the cathode side plate are connected to each other through a communication hole in which a part of the gasket is opened in the anode side plate or the cathode side plate. It is glued between the two.

  According to a fourth aspect of the present invention, there is provided the fuel cell sealing structure according to the first aspect, wherein the gasket is brought into close contact with the power generator in an appropriate compression state and is pressed against the adjacent gasket or separator. A first seal protrusion and a second seal protrusion that is in close contact with the adjacent gasket or separator in an appropriate compression state are formed.

  According to the fuel cell sealing structure of the first aspect of the present invention, since the anode side plate and the cathode side plate become a single separator integrally having a gasket, the number of laminated parts and the number of laminating steps at the time of stack assembly are greatly increased. And the accuracy of stacking can be improved.

  According to the fuel cell sealing structure of the second aspect of the present invention, in addition to the effect of the first aspect, the first seal protrusion defining the reaction gas flow path (for example, the fuel gas flow path) on one side of the power generator. A second seal protrusion that defines a reaction gas flow path (for example, an oxidant gas flow path) on the other side of the power generator, a refrigerant seal portion that defines a refrigerant flow path, and an anode side plate Since they are provided in a single separator made of a cathode side plate, it is not necessary to form gaskets with different sealing targets into a plurality of laminated parts, and the number of molding steps can be reduced.

  According to the fuel cell sealing structure of the third aspect of the invention, in addition to the effect of the first aspect, a part of the molding material is immediately filled between the anode side plate and the cathode side plate through the communication hole when the gasket is formed. Therefore, molding can be performed easily.

  According to the fuel cell sealing structure of the invention of claim 4, in addition to the effect of claim 1, the reaction gas flow on both sides of the power generator is caused by the first seal protrusion and the second seal protrusion of the gasket. In addition to defining a passage and defining a refrigerant flow path by a portion of the gasket interposed between the anode side plate and the cathode side plate, a single gasket provides a reaction gas flow path (fuel gas) independent of each other. Flow paths and oxidant gas flow paths) and refrigerant flow paths can be defined.

It is a fragmentary sectional view which shows the 1st form of the sealing structure of the fuel cell which concerns on this invention in the non-stacked state. It is a fragmentary sectional view which shows the 1st form of the sealing structure of the fuel cell which concerns on this invention in a lamination | stacking state. It is a fragmentary sectional view which shows an example of the reinforcement structure of the electric power generation body in the sealing structure of the fuel cell which concerns on this invention. It is a fragmentary sectional view which shows the other example of the reinforcement structure of the electric power generation body in the sealing structure of the fuel cell which concerns on this invention. It is a fragmentary sectional view which shows the 2nd form of the sealing structure of the fuel cell which concerns on this invention in the non-stacked state. It is a fragmentary sectional view which shows the 2nd form of the sealing structure of the fuel cell which concerns on this invention in a lamination | stacking state. It is a fragmentary sectional view which shows the partial modification in the 2nd form of the sealing structure of the fuel cell which concerns on this invention. It is a fragmentary sectional view which shows the other partial modification in the 2nd form of the sealing structure of the fuel cell which concerns on this invention. It is a fragmentary sectional view which shows the other partial modification in the 2nd form of the sealing structure of the fuel cell which concerns on this invention. It is a fragmentary sectional view which shows the sealing structure of the fuel cell by a prior art in the non-stacked state. It is a fragmentary sectional view which shows the sealing structure of the fuel cell by a prior art in a lamination | stacking state.

  Hereinafter, a preferred embodiment of a fuel cell sealing structure according to the present invention will be described in detail with reference to the drawings.

  First, FIG. 1 shows a first embodiment of a fuel cell sealing structure according to the present invention in a non-laminated state, and FIG. 2 shows a laminated state. Reference numeral 10 in the figure is provided on the electrolyte membrane and both surfaces thereof. Further, a gas diffusion layer (GDL) 12 made of a porous material is formed on both sides in the thickness direction of a membrane electrode assembly (MEA) 11 made of a catalyst electrode layer (anode and cathode) (not shown). , 13 are integrated with each other, reference numeral 20 is a separator, and reference numeral 30 is a gasket provided integrally with the separator 20.

  The membrane-electrode assembly 11 in the power generation body 10 has a larger projected area in the thickness direction than the gas diffusion layers 12 and 13 on both sides thereof, and the outer peripheral edges of the gas diffusion layers 12 and 13 are formed on the membrane-electrode assembly. 11 recedes from the outer peripheral edge to the inner peripheral side. Therefore, the outer peripheral portion of the power generator 10 has a stepped shape, and the outer peripheral portion of the membrane-electrode assembly 11 projects from the edge portions of the gas diffusion layers 12 and 13.

  Further, as shown in FIG. 3 or FIG. 4, the outer peripheral portion of the membrane-electrode assembly 11 protruding from the edge of the gas diffusion layers 12 and 13 is thermocompression-bonded with a reinforcing film 14 made of synthetic resin on at least one side. The inner peripheral edge of the reinforcing film 14 is sandwiched between the edge of the gas diffusion layer 12 (and 13) and the membrane-electrode assembly 11. In addition, when providing the reinforcement film 14 only on one side like FIG. 4, it is preferable to provide in the side used as the sealing surface by the 1st seal protrusion 31 mentioned later.

  The separator 20 is a laminate of two plates 21 and 22 made of conductive metal such as a thin stainless steel plate. The projected area in the thickness direction of the separator 20 is the power generator 10 (membrane-electrode assembly 11). ) Is larger than the projected area in the thickness direction. In the following description, the plate 21 is described as the anode side and the plate 22 is described as the cathode side for convenience. However, the plate 21 may be the cathode side and the plate 22 may be the anode side.

  Of the plates 21 and 22 constituting the separator 20, the anode side plate 21 facing the gas diffusion layer 12 of the power generator 10 laminated on one side in the thickness direction of the separator 20 has the thickness of the gas diffusion layer 12. In the region projected in the direction, groove portions 21a bent in the opposite direction to the direction facing the gas diffusion layer 12 and groove portions 21b bent in the direction facing the gas diffusion layer 12 are alternately formed, A pair of bent portions 21c and 21d bent in the same direction as the groove portion 21b are formed in the vicinity of both ends in the width direction of the gasket 30 in the region where the gasket 30 is integrally provided.

  In addition, among the plates 21 and 22 constituting the separator 20, the cathode side plate 22 facing the gas diffusion layer 13 of the power generation body 10 stacked on the other side in the thickness direction of the separator 20 is thicker than the anode side plate 21. Groove portions 22a and 22b and bent portions 22c and 22d that are bent symmetrically in the vertical direction are formed.

  The gasket 30 is an electrically insulating rubber-like elastic material (rubber or rubber-like elasticity selected from, for example, silicone rubber, fluorine rubber, EPDM (ethylene propylene diene rubber), butyl rubber, etc. that can withstand the usage environment of the fuel cell. A first sealing ridge 31 and a second sealing ridge that are integrally vulcanized and molded into the separator 20 with the anode side plate 21 projecting to the opposite side of the cathode side plate 22. 32 and first short-circuit prevention ribs 33 and second short-circuit prevention ribs 34 on both sides in the width direction, a flat seal portion 35 formed on the cathode-side plate 22 on the opposite side to the anode-side plate 21, and the anode-side plate 21. Between the bent portions 21c and 21d and the bent portions 22c and 22d of the cathode side plate 22 facing the bent portions 21c and 21d And an intermediate rubber packing 36, 37 has been made.

  Specifically, in the non-laminated state shown in FIG. 1, the first seal protrusion 31 in the gasket 30 has a mountain-shaped protruding shape, and in the laminated state shown in FIG. 2, the edges of the gas diffusion layers 12 and 13 of the power generation body 10. It is brought into close contact with the outer peripheral part (or the reinforcing film 14 shown in FIGS. 3 and 4) of the membrane-electrode assembly 11 protruding from the part with an appropriate crushing margin.

  The second seal ridge 32 in the gasket 30 is on the outer peripheral side of the first seal ridge 31 and has a chevron-like protruding shape in the non-laminated state shown in FIG. 1, and in the laminated state shown in FIG. It is in close contact with the flat seal portion 35 of the gasket 30 adjacent outside the edge of the power generator 10 (membrane-electrode assembly 11) with an appropriate crushing margin, and preferably the thickness of the membrane-electrode assembly 11. The protrusion height is formed higher than the first seal protrusion 31 by an amount corresponding to this.

  The first short-circuit prevention rib 33 formed on the inner peripheral side of the first seal protrusion 31 in the gasket 30 projects from the edge of the gas diffusion layers 12 and 13 of the power generator 10 in the stacked state shown in FIG. The membrane-electrode assembly 11 is in close contact with the outer peripheral portion (or the reinforcing film 14 shown in FIGS. 3 and 4) with a flat surface, and the bent portion 21c of the anode side plate 21 in the separator 20 is provided. The protrusion height is lower than that of the first seal protrusion 31 by an amount substantially corresponding to the crushing allowance.

  The second short-circuit prevention rib 34 formed on the outer peripheral side of the second seal protrusion 32 in the gasket 30 is more than the edge of the power generator 10 (membrane-electrode assembly 11) in the laminated state shown in FIG. The flat seal portion 35 of the gasket 30 adjacent on the outside is brought into close contact with a flat surface, and is formed so as to cover the bent portion 21d of the anode side plate 21 in the separator 20, and its protruding height is shown in FIG. As shown in FIG. 5, the second seal protrusion 32 is lower by an amount corresponding to the crushing margin and higher than the first short-circuit prevention rib 33 by an amount corresponding to the thickness of the membrane-electrode assembly 11. Is formed.

  The flat seal portion 35 in the gasket 30 is formed with a flat surface so as to cover the surface opposite to the anode side plate 21 from the bent portion 22c to the bent portion 22d of the cathode side plate 22 in the separator 20. .

  In addition, communication holes 21e and 21f are formed in the bent portions 21c and 21d of the anode side plate 21 of the separator 20, respectively. Similarly, the communication holes 22e and 22f are also formed in the bent portions 22c and 22d of the cathode side plate 22, respectively. Has been established. The intermediate rubber filling portion 36 on the inner peripheral side of the gasket 30 is formed so as to fill a space between the bent portion 21c of the anode side plate 21 and the bent portion 22c of the cathode side plate 22, and is vulcanized and bonded to the inner surface thereof. In addition, the first short-circuit prevention rib 33 and the flat seal portion 35 are continuous via the communication holes 21e and 22e, and the intermediate rubber filling portion 37 on the outer peripheral side is the bent portion 21d of the anode side plate 21 and the cathode side plate. 22 is formed so as to fill the space between the bent portions 22d and is vulcanized and bonded to the inner surface thereof, and is continuous with the second short-circuit prevention rib 34 and the flat seal portion 35 through the communication holes 21f and 22f.

  Therefore, the gasket 30 includes a first seal protrusion 31, a second seal protrusion 32, a first short-circuit prevention rib 33 and a second short-circuit prevention rib 34 formed on one side of the separator 20, A flat seal portion 35 formed on the other side is continuous via the intermediate rubber filling portions 36 and 37 and integrally connects the anode side plate 21 and the cathode side plate 22 in the separator 20 to each other.

  In the stacked state shown in FIG. 2, the outer peripheral portion of the membrane-electrode assembly 11 in the power generation body 10 includes the first seal protrusions 31 and the first short-circuit prevention ribs 33 of the gasket 30 provided integrally with the separator 20. And the gas diffusion layers 12 and 13 in the power generator 10 are sandwiched between the separator 20 and the flat seal portion 35 of the gasket 30 provided integrally with the other separator 20 adjacent in the thickness direction. The region where the grooves 21a and 21b are formed in the anode side plate 21 of the separator 20 and the region where the grooves 22a and 22b are formed in the cathode side plate 22 of another separator 20 adjacent to the separator 20 in the thickness direction. It is sandwiched in a state of being appropriately compressed between them.

  Between the gas diffusion layer 12 of the power generation body 10 and the groove 21a of the anode-side plate 21 of the separator 20 in contact with the gas diffusion layer 12, a fuel gas flow path F1 for flowing hydrogen-containing fuel gas is formed. The region where the fuel gas flow path F1 is formed is in close contact with the outer peripheral portion of the membrane-electrode assembly 11 (or the reinforcing film 14 shown in FIGS. 3 and 4) in the power generation body 10 with an appropriate crushing allowance. The first seal protrusion 31 is partitioned independently from other regions. That is, the fuel gas is supplied to the anode which is the catalyst electrode layer on the gas diffusion layer 12 side in the membrane-electrode assembly 11 via the fuel gas flow path F1 and the gas diffusion layer 12. The fuel gas flow path F1 corresponds to a reaction gas flow path on one side of the power generator described in claim 2.

  Further, an oxidant gas flow path F2 for flowing an oxidant gas containing oxygen is provided between the other gas diffusion layer 13 of the power generation body 10 and the groove 22a of the cathode side plate 22 of the separator 20 in contact with the gas diffusion layer 13. The formed region where the oxidant gas flow path F2 is formed is a second region which is in close contact with the flat seal portion 35 with an appropriate crushing margin outside the edge of the power generator 10 (membrane-electrode assembly 11). The seal protrusion 32 is partitioned independently from other regions. That is, the oxidant gas is supplied to the cathode, which is the catalyst electrode layer on the gas diffusion layer 13 side in the membrane-electrode assembly 11, via the oxidant gas flow path F 2 and the gas diffusion layer 13. The oxidant gas flow path F2 corresponds to the reaction gas flow path on the other side of the power generator described in claim 2.

  In addition, a refrigerant flow path F3 through which refrigerant (cooling water) flows is formed between the groove 21b of the anode side plate 21 in the separator 20 and the groove 22b of the cathode side plate 22 in contact with the anode side plate 21. The region where the refrigerant flow path F3 is formed is formed by the intermediate rubber filling portion 36 of the gasket 30 formed so as to fill the space between the bent portion 21c of the anode side plate 21 and the bent portion 22c of the cathode side plate 22. It is partitioned independently from other areas. A refrigerant such as cooling water is circulated through the refrigerant flow path F3.

  Therefore, the intermediate rubber filling portion 36 serves as a means for integrally connecting the anode side plate 21 and the cathode side plate 22 to each other and a means as a refrigerant seal portion described in claim 2.

  According to the first embodiment configured as described above, in the stacked state shown in FIG. 2, the fuel gas flow to the anode (not shown) that is one catalyst electrode layer of the membrane-electrode assembly 11 in the power generation body 10. Hydrogen-containing fuel gas is supplied via the path F1 and the gas diffusion layer 12, and the oxidant gas flow path F2 and the gas diffusion layer 13 are connected to the cathode (not shown) which is the other catalyst electrode layer of the membrane-electrode assembly 11. Oxygen-containing oxidant gas (air) is supplied through this, and electric power is generated by an electrochemical reaction that is a reverse reaction of water electrolysis, that is, a reaction that generates water from hydrogen and oxygen. The electromotive force in each power generation unit composed of the power generation body 10 and the separator 20 with the gasket 30 is low, but a large number of these power generation bodies 10 and separators 20 with the gasket 30 are alternately stacked to electrically connect each power generation unit. Thus, the necessary electromotive force can be obtained by connecting them in series. The reaction heat generated at this time is removed by the refrigerant flowing through the refrigerant flow path F3.

  The separator 20 with the gasket 30 includes a first seal protrusion 31 that is in close contact with an outer peripheral portion of the membrane-electrode assembly 11 in the power generation body 10 with an appropriate crushing margin, and an edge portion of the membrane-electrode assembly 11. A second seal protrusion 32 which is in close contact with the flat seal portion 35 of the gasket 30 adjacent on the outside with an appropriate crushing margin, an intermediate rubber filling portion 36 interposed between the anode side plate 21 and the cathode side plate 22, In other words, means for defining the fuel gas flow path F1, the oxidant gas flow path F2, and the refrigerant flow path F3 that are independent of each other are collectively provided in the separator 20. For this reason, it is not necessary to integrally form a gasket on a plurality of laminated parts as in the prior art, and the number of molding steps can be reduced.

  The gasket 30 includes a first seal protrusion 31, a second seal protrusion 32, a first short-circuit prevention rib 33, and a second short-circuit prevention rib 34 formed on one side of the separator 20, and vice versa. The flat seal portion 35 formed on the side includes communication holes 21e, 22e and 21f, 22f provided in the bent portions 21c, 21d of the anode side plate 21 and the bent portions 22c, 22d of the cathode side plate 22 opposite to the bent portions 21c, 21d. Therefore, the gaskets 30 need not be formed from both sides of the separator 20 and can be simultaneously formed from one side of the separator 20.

  Moreover, since the anode side plate 21 and the cathode side plate 22 are integrated as the separator 20 by the gasket 30, each power generation unit of the fuel cell has the membrane-electrode assembly 11 and the gas as shown in FIG. There are only two parts, the power generation body 10 with the diffusion layers 12 and 13 bonded together and the separator 20 with the gasket 30. Therefore, the number of laminated parts is reduced, and the number of assembling steps in stack assembling can be reduced. As a result, the lamination error due to the accumulation of slight misalignment between the parts can be reduced.

  Further, the gaskets 30, 30,... Adjacent to each other in the thickness direction are arranged between the first short-circuit prevention rib 33 and the flat seal portion 35 in the laminated state shown in FIG. The deformation | transformation can be suppressed by inserting | pinching the outer peripheral part of the electrode complex 11, and the 2nd short circuit prevention rib press-contacted on the flat surface between the separators 20, 20, ... which are mutually adjacent in the thickness direction. By interposing 34 and the flat seal portion 35, an electrical short circuit due to contact between the ends of the anode side plate 21 and the cathode side plate 22 on both sides of the power generation body 10 can be effectively prevented.

  In the first embodiment described above, the first and second seal protrusions 31 and 32, the first and second short-circuit preventing ribs 33 and 34 in the gasket 30, and the flat seal portion 35 on the opposite side thereof, The intermediate rubber filling portions 36 and 37 in the meantime are continuous with each other through the communication holes 21e and 22e and 21f and 22f. The second seal protrusions 31 and 32, the first and second short-circuit preventing ribs 33 and 34, and the flat seal portion 35 may be continuous with each other.

  Next, FIG. 5 shows a second form of the fuel cell sealing structure according to the present invention in an unstacked state, and FIG. 6 shows the same in a stacked state.

  The second embodiment is different from the first embodiment described above in that the two plates 23 and 24 constituting the separator 20 are formed of carbon and straddle the plates 23 and 24. A gasket 40 made of an electrically insulating rubber-like elastic material (rubber or synthetic resin material having rubber-like elasticity) is integrally vulcanized and molded. In the following description, for convenience, the plate 23 will be described as the anode side and the plate 24 as the cathode side, but conversely, the plate 23 may be the cathode side and the plate 24 may be the anode side.

  That is, the anode side plate 23 in the separator 20 is made of a carbon molded body, and a groove 23 a is formed on the surface facing the gas diffusion layer 12 of the power generation body 10 laminated on one side in the thickness direction of the separator 20. A groove 23 b is formed on the opposite surface, that is, the abutting surface with the cathode side plate 24. Further, a flat seal holding surface 23c is formed on the outer peripheral side of the region where the groove 23a is formed. The flat seal holding surface 23c is retreated appropriately in the direction opposite to the direction facing the power generator 10, and the outer peripheral side of the region where the groove 23b is formed. Is formed with a belt-like groove 23d, and a communication hole 23e penetrating therethrough in the thickness direction is formed.

  Further, the cathode side plate 24 in the separator 20 is also made of a carbon molded body, and a groove 24 a is formed on the surface facing the gas diffusion layer 13 of the power generation body 10 laminated on the other side in the thickness direction of the separator 20. Further, a flat flange portion 24b is formed in the outer peripheral side region so as to protrude in a direction opposite to the power generation body 10 with a protrusion amount smaller than the thickness of the gas diffusion layer 13.

  The gasket 40 is an electrically insulating rubber-like elastic material (rubber or rubber-like elastic material selected from, for example, silicone rubber, fluorine rubber, EPDM (ethylene propylene diene rubber), butyl rubber, etc. that can withstand the usage environment of the fuel cell. A first sealing ridge 41 and a second sealing ridge that are integrally vulcanized and molded into the separator 20 with the anode side plate 23 projecting to the opposite side of the cathode side plate 24. 42, first short-circuit prevention ribs 43 and second short-circuit prevention ribs 44 on both sides in the width direction, and a third seal formed between the first seal protrusion 41 and the second seal protrusion 42. A short-circuit preventing rib 45 and an intermediate rubber filling portion 46 interposed between the anode side plate 23 and the cathode side plate 24 are provided.

  Specifically, the first seal protrusion 41 in the gasket 40 has a mountain-shaped protruding shape in the non-laminated state shown in FIG. 5, and the edges of the gas diffusion layers 12 and 13 of the power generator 10 in the laminated state shown in FIG. It is brought into close contact with the outer peripheral portion (or the reinforcing film 14 shown in FIGS. 3 and 4) of the membrane-electrode assembly 11 protruding from the portion with an appropriate crushing margin.

  The second seal protrusion 42 in the gasket 40 is on the outer peripheral side of the first seal protrusion 41 and has a mountain-shaped protrusion shape in the non-laminated state shown in FIG. 5, and power generation in the laminated state shown in FIG. It is in close contact with the flange portion 24b of the cathode side plate 24 of the separator 20 adjacent outside the edge portion of the body 10 (membrane-electrode assembly 11) with an appropriate crushing margin, preferably the membrane-electrode assembly. The protrusion height is higher than the first seal protrusion 41 by an amount corresponding to the thickness of 11.

  The first short-circuit prevention rib 43 formed on the inner peripheral side of the first seal protrusion 41 in the gasket 40 and the third short-circuit prevention rib 45 formed on the outer periphery side of the first seal protrusion 41 are: In the laminated state shown in FIG. 6, the outer periphery (or the reinforcing film 14 shown in FIGS. 3 and 4) of the membrane-electrode assembly 11 protruding from the edges of the gas diffusion layers 12 and 13 of the power generator 10 is flat. The projecting height is higher than the step between the formation surface of the groove 23a and the seal holding surface 23c, and substantially corresponds to the crushing allowance of the first seal protrusion 41. The projecting height is as low as it does.

  The second short-circuit prevention rib 44 formed on the outer peripheral side of the second seal protrusion 42 in the gasket 40 is more than the edge of the power generator 10 (membrane-electrode assembly 11) in the stacked state shown in FIG. A flat surface is in close contact with the flange portion 24b of the cathode side plate 24 of the separator 20 adjacent on the outside, and the protruding height is higher than that of the second seal protrusion 42 as shown in FIG. It is lower by an amount substantially corresponding to the crushing allowance and higher than the first short-circuit prevention rib 43 and the third short-circuit prevention rib 45 by an amount corresponding to the thickness of the membrane-electrode assembly 11.

  The intermediate rubber filling portion 46 in the gasket 40 is formed so as to be filled between the belt-like groove 23d of the anode side plate 23 and the cathode side plate 24 abutted against the anode side plate 23 so as to close the groove 23d. While being vulcanized and bonded, it is continuous with the second short-circuit prevention rib 44 through the communication hole 23e.

  Accordingly, the gasket 40 includes the first seal protrusion 41, the second seal protrusion 42, the first short-circuit prevention rib 43, the second short-circuit prevention rib 44, and the third formed on one side of the anode side plate 23. The short-circuit prevention rib 45 and the intermediate rubber filling portion 46 formed on the other side are continuous with each other, and the intermediate rubber filling portion 46 vulcanized and bonded to the belt-like groove 23 d of the anode side plate 23 and the cathode side plate 24. Thus, the anode side plate 23 and the cathode side plate 24 are integrally connected to each other.

  In the laminated state shown in FIG. 6, the outer peripheral portion of the membrane-electrode assembly 11 in the power generation body 10 includes the first seal protrusion 41 and the first short-circuit prevention rib 43 of the gasket 40 provided integrally with the separator 20. The gas diffusion layer 12 in the power generator 10 is sandwiched between the third short-circuit prevention rib 45 and the flange portion 24b of the cathode-side plate 24 of the separator 20 adjacent to the separator 20 in the thickness direction. , 13 are appropriately compressed between the formation region of the groove 23a in the anode side plate 23 of the separator 20 and the formation region of the groove 24a in the cathode side plate 24 of another separator 20 adjacent in the thickness direction. It is pinched.

  Between the gas diffusion layer 12 of the power generation body 10 and the groove 23a of the anode side plate 23 of the separator 20 in contact with the gas diffusion layer 12, a fuel gas flow path F1 through which hydrogen-containing fuel gas flows is formed. The region where the fuel gas flow path F1 is formed is in close contact with the outer peripheral portion of the membrane-electrode assembly 11 (or the reinforcing film 14 shown in FIGS. 3 and 4) in the power generation body 10 with an appropriate crushing allowance. The first seal protrusion 41 is partitioned independently from other regions. That is, the fuel gas is supplied to the anode which is the catalyst electrode layer on the gas diffusion layer 12 side in the membrane-electrode assembly 11 via the fuel gas flow path F1 and the gas diffusion layer 12.

  Further, an oxidant gas flow path F2 for flowing an oxidant gas containing oxygen is provided between the other gas diffusion layer 13 of the power generation body 10 and the groove 24a of the cathode side plate 24 of the separator 20 in contact therewith. The region where the oxidant gas flow path F2 is formed is formed on the flange portion 24b of the cathode side plate 24 adjacent to the power generator 10 (membrane-electrode assembly 11) in the thickness direction outside the edge portion. It is divided independently from other regions by the second seal protrusion 42 which is brought into close contact with an appropriate crushing margin. That is, the oxidant gas is supplied to the cathode, which is the catalyst electrode layer on the gas diffusion layer 13 side in the membrane-electrode assembly 11, via the oxidant gas flow path F 2 and the gas diffusion layer 13.

  Further, a refrigerant flow path F3 for circulating a refrigerant (cooling water) is formed between the groove 23b of the anode side plate 23 in the separator 20 and the cathode side plate 24 in contact with the anode side plate 23. The region where the refrigerant flow path F3 is formed is independent of other regions by the intermediate rubber filling portion 46 of the gasket 40 formed so as to fill the gap between the belt-like groove 23d of the anode side plate 23 and the cathode side plate 24. Partitioned. A refrigerant such as cooling water is circulated through the refrigerant flow path F3.

  Therefore, the intermediate rubber filling portion 46 serves as a means for integrally connecting the anode side plate 23 and the cathode side plate 24 to each other and a means as a refrigerant seal portion described in claim 2.

  According to the second embodiment configured as described above, in the stacked state shown in FIG. 6, the fuel gas flows to the anode (not shown) that is one catalyst electrode layer of the membrane-electrode assembly 11 in the power generation body 10. Hydrogen-containing fuel gas is supplied via the path F1 and the gas diffusion layer 12, and the oxidant gas flow path F2 and the gas diffusion layer 13 are connected to the cathode (not shown) which is the other catalyst electrode layer of the membrane-electrode assembly 11. Oxygen-containing oxidant gas (air) is supplied through this, and electric power is generated by an electrochemical reaction that is a reverse reaction of water electrolysis, that is, a reaction that generates water from hydrogen and oxygen. The electromotive force in each power generation unit composed of the power generation body 10 and the separator 20 with the gasket 40 is low, but a large number of these power generation bodies 10 and separators 20 with the gasket 40 are alternately stacked to electrically connect each power generation unit. Thus, the necessary electromotive force can be obtained by connecting them in series. The reaction heat generated at this time is removed by the refrigerant flowing through the refrigerant flow path F3.

  The gasket 40 includes a first seal protrusion 41 that is in close contact with an outer peripheral portion of the membrane-electrode assembly 11 in the power generation body 10 with an appropriate crushing margin, and an outer side than an edge portion of the membrane-electrode assembly 11. The second seal protrusion 42 is brought into close contact with the flange portion 24 b of the cathode side plate 24 with an appropriate crushing margin, and the intermediate rubber filling portion 46 is interposed between the anode side plate 23 and the cathode side plate 24. Therefore, in other words, means for defining the fuel gas flow path F1, the oxidant gas flow path F2, and the refrigerant flow path F3 that are independent from each other are collectively provided in the separator 20. For this reason, it is not necessary to integrally form a gasket on a plurality of laminated parts as in the prior art, and the number of molding steps can be reduced.

  Further, the intermediate rubber filling portion 46 in the gasket 40 is vulcanized and bonded to the inner surfaces of both the belt-like groove 23d of the anode side plate 23 and the cathode side plate 24, whereby the anode side plate 23 and the cathode side plate 24 are separated from each other. As shown in FIG. 5, each power generation unit of the fuel cell has a power generation body 10 in which the membrane-electrode assembly 11 and the gas diffusion layers 12 and 13 are bonded, and a gasket 40. There are only two parts of the separator 20. Therefore, the number of laminated parts is reduced, and the number of assembling steps in stack assembling can be reduced. As a result, the lamination error due to the accumulation of slight misalignment between the parts can be reduced.

  Further, the first short-circuit prevention rib 43 and the third short-circuit prevention rib 45 in the gasket 40 together with the first seal protrusion 41, the outer peripheral portion of the membrane-electrode assembly 11 of the power generator 10 is formed on the cathode side plate 24. The deformation can be suppressed by pressing against the flat flange portion 24b, and between the separators 20, 20,... By interposing the short-circuit prevention ribs 44, electrical short-circuits caused by contact between the ends of the anode side plate 23 and the cathode side plate 24 on both sides of the power generation body 10 can be effectively prevented.

  Next, FIG. 7 to FIG. 9 show partial modifications of the second form of the fuel cell sealing structure according to the present invention.

  7 shows that a belt-like groove 24c facing the belt-like groove 23d of the anode-side plate 23 is formed on the abutting surface of the cathode-side plate 24 of the separator 20 with the anode-side plate 23. 46 is filled across both the belt-like grooves 23d and 24c and vulcanized and bonded to the inner surface thereof. Other configurations are the same as those of FIGS. 5 and 6 described above.

  In this way, the adhesive force is increased by the anchor effect of the intermediate rubber filling portion 46 to the inner surface of the belt-like groove 24c, and the bonding force between the anode side plate 23 and the cathode side plate 24 can be improved.

  8 and 9, the air vent groove 20a extending from the belt-like groove 23d of the anode side plate 23 to the outer peripheral side and the surplus material reservoir 20b at the tip thereof are formed on the surface of the anode side plate 23 facing the cathode side plate 24. It is a thing. The air vent groove 20a and the surplus material reservoir 20b may be formed on the surface of the cathode side plate 24 facing the anode side plate 23, and the other configurations are the same as those of FIGS. 5 and 6 described above.

  In this manner, when the anode side plate 23 and the cathode side plate 24 are stacked and set in a mold (not shown) and the gasket 40 is molded from a liquid rubber material, the communication hole 23e of the anode side plate 23 is formed. As the liquid rubber material is filled into the space between the belt-like groove 23d and the cathode side plate 24 from the air, residual air and volatile gas in this space are discharged to the surplus material reservoir 20b through the air vent groove 20a, The surplus liquid rubber material merged in the step can also flow into the surplus material reservoir 20b through the air vent groove 20a. For this reason, since the liquid rubber material is well shaped in the space and the intermediate rubber filling portion 46 is molded, molding defects are effectively prevented.

  In the second embodiment, the first and second seal protrusions 41 and 42, the first to third short-circuit preventing ribs 43 to 45, and the intermediate rubber filling portion 46 in the gasket 40 have the communication hole 23e. The first and second sealing ridges 41, 42, the first to second seal protrusions 41, 42 are formed by turning a part of the gasket 40 around the edge of the separator 20 without opening the communication hole 23e. The third short-circuit prevention ribs 43 to 45 and the intermediate rubber filling portion 46 may be continuous with each other.

DESCRIPTION OF SYMBOLS 10 Electric power generation body 11 Membrane-electrode assembly 12, 13 Gas diffusion layer 20 Separator 21, 23 Anode side plate 21e, 21f, 22e, 22f, 23e Communication hole 22, 24 Cathode side plate 23d Strip-like groove 30, 40 Gasket 31, 41 First seal protrusions 32, 42 Second seal protrusions 33, 43 First short-circuit prevention ribs 34, 44 Second short-circuit prevention ribs 35 Flat seal portions 36, 46 Intermediate rubber filling portion (refrigerant seal portion)
37 Intermediate rubber filling portion 45 Third short-circuit prevention rib F1 Fuel gas flow path (reactive gas flow path on one side of the power generation body)
F2 Oxidant gas channel (reactive gas channel on the other side of the power generator)
F3 refrigerant flow path

Claims (4)

  A power generator having a membrane-electrode composite provided with an anode and a cathode on both surfaces of an electrolyte membrane and a separator integrally provided with a gasket are alternately stacked in the thickness direction, and the separator is aligned in the thickness direction. A reaction gas flow path is formed between an anode side plate that forms a reaction gas flow path between the anode side of the power generation body arranged on the side and a cathode side of the power generation body arranged on the other side, and A fuel cell sealing structure, wherein a cathode side plate forming a refrigerant flow path with an anode side plate is integrally connected to each other through a part of the gasket.   A gasket is adjacent to an outer peripheral portion of the power generation body to form a reaction gas flow path on one side of the power generation body, and a gasket adjacent outside the edge of the power generation body. Alternatively, a second seal protrusion that defines a reaction gas flow path on the other side of the power generator by being in close contact with the separator, and an inner periphery thereof interposed between outer peripheral portions of the anode side plate and the cathode side plate. The fuel cell sealing structure according to claim 1, further comprising a refrigerant seal portion that defines a side refrigerant flow path.   2. The fuel cell sealing structure according to claim 1, wherein a part of the gasket is adhered between the anode side plate and the cathode side plate through a communication hole formed in the anode side plate or the cathode side plate.   A first seal protrusion that presses the power generator against an adjacent gasket or separator in an appropriate compression state and a gasket that is pressed into the gasket or separator in an appropriate compression state. 2. The fuel cell sealing structure according to claim 1, wherein two sealing protrusions are formed.

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