JP2005100950A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely prevent the shortcut of reaction gas and secure desirable power generation performance in simple constitution. <P>SOLUTION: A second sealing member 56 is integrated with surfaces 18a, 18b of an anode side metallic separator 18. The second sealing member 56 has an outside seal 58a and an inside seal 58b installed on a surface 18a of the anode side metallic separator 18. A plurality of blocking seals 60 are integrally formed at an internal circumferential end part of the inside seal 58b, and the blocking seals 60 blocks a gap between the inside seal 58b and a projection part 44a of a fuel gas passage 44. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention includes an electrolyte membrane / electrode structure in which a first electrode and a second electrode are disposed on both sides of an electrolyte membrane, and the electrolyte membrane / electrode structure is disposed between first and second separators. In addition, the present invention relates to a fuel cell in which a reaction gas flow path for supplying a predetermined reaction gas along the first and second electrodes is formed in each of the first and second separators.

  For example, a polymer electrolyte fuel cell has an electrolyte membrane / electrode structure (MEA) in which an anode side electrode and a cathode side electrode are respectively provided on both sides of an electrolyte membrane made of a polymer ion exchange membrane (cation exchange membrane). Is provided with a power generation cell sandwiched between separators. This type of fuel cell is normally used as a fuel cell stack by stacking a predetermined number of power generation cells.

  In this power generation cell, the fuel gas supplied to the anode side electrode, for example, a gas mainly containing hydrogen (hereinafter also referred to as hydrogen-containing gas) is ionized with hydrogen on the electrode catalyst, and the cathode passes through the electrolyte membrane. Move to the side electrode side. Electrons generated during that time are taken out to an external circuit and used as direct current electric energy. The cathode side electrode is supplied with an oxidant gas, for example, a gas mainly containing oxygen or air (hereinafter also referred to as an oxygen-containing gas). And oxygen reacts to produce water.

  In the power generation cell described above, various seal structures are employed in order to keep the fuel gas and the oxidant gas airtight. For example, Patent Document 1 discloses a fuel cell capable of improving the sealing performance between an electrolyte membrane / electrode structure and a separator.

  As shown in FIG. 15, this fuel cell includes a power generation cell in which an electrolyte membrane / electrode structure 1 is sandwiched between first and second separators 2a and 2b. The electrolyte membrane / electrode structure 1 includes a solid polymer electrolyte membrane 3, and an anode side electrode 4 a and a cathode side electrode 4 b that sandwich the solid polymer electrolyte membrane 3, and the anode side electrode 4 a is the cathode The surface area is set larger than that of the side electrode 4b. That is, the electrolyte membrane / electrode structure 1 constitutes a so-called step MEA.

  A first seal 5a that is in close contact with the solid polymer electrolyte membrane 3 is attached to the inner surface side of the second separator 2b so as to surround the cathode side electrode 4b. Further, a second seal 5b is attached between the first and second separators 2a and 2b so as to surround the first seal 5a.

Japanese Patent Laying-Open No. 2002-25587 (paragraph [0017], FIG. 7)

  By the way, in said patent document 1, the clearance gap 6 is easy to be formed between the cathode side electrode 4b and the 1st seal | sticker 5a. In particular, when the second separator 2b is formed of a metal separator, the second separator 2b is pressed by a mold (not shown) when the first seal 5a is integrally formed on the second separator 2b. A mold pressing surface (flat surface) is required. For this reason, a relatively wide gap 6 is formed between the cathode side electrode 4b and the first seal 5a in correspondence with the above-described pressing surface.

  Accordingly, the reaction gas easily leaks into the gap 6, and this reaction gas may not pass along the reaction gas flow path (not shown) and pass through the outer peripheral portion of the cathode side electrode 4 b. This is the generation of a so-called reactive gas shortcut. As a result, there is a problem that the reaction gas cannot be reliably supplied to the electrode reaction surface, and good power generation performance is not maintained.

  The present invention solves this type of problem, and provides a fuel cell capable of reliably preventing a reactive gas shortcut with a simple configuration and ensuring a desired power generation performance. Objective.

  A fuel cell according to the present invention includes an electrolyte membrane / electrode structure in which a first electrode and a second electrode are disposed on both sides of an electrolyte membrane, and the electrolyte membrane / electrode structure is provided with first and second electrolyte membranes. In addition to being disposed between the separators, the first and second separators are formed with reaction gas flow paths for supplying predetermined reaction gases along the first and second electrodes, respectively.

  At least the first separator is provided with a seal member so as to cover the outer peripheral edge of the first separator, and the seal member has a frame-like seal surface facing the first electrode, A plurality of blocking seals that prevent reaction gas from flowing along the gap in the gap between the inner peripheral end of the frame-shaped seal surface and the convex portion of the reaction gas flow channel adjacent to the inner peripheral end. Is provided.

  The number, shape (width dimension), and arrangement position of the closing seal are variously set corresponding to the site where the reaction gas is actually likely to leak. The closing seal is not limited to the one that completely closes the gap, and may be closed to such an extent that the flow of the reaction gas is effectively limited.

  Further, the closing seal is preferably formed integrally with the inner peripheral end of the frame-shaped sealing surface, and protrudes in an inclined direction away from the first separator.

  Further, the closing seal is preferably a plurality of liquid seals filled in the gap between the inner peripheral end portion of the frame-shaped sealing surface and the convex portion of the reaction gas channel.

  Furthermore, the closing seal is preferably a plurality of solid seals disposed in the gap between the inner peripheral end portion of the frame-shaped sealing surface and the convex portion of the reaction gas channel.

  Further, the first and second separators are provided with a reaction gas channel for supplying a reaction gas to the first and second electrodes, respectively, along the surface direction, and the reaction gas channel has a folded portion. It is preferable to constitute the meandering flow path.

  According to the present invention, the seal member has a plurality of gaps between the inner peripheral end portion of the frame-shaped seal surface facing the first electrode and the convex portion of the reaction gas channel adjacent to the inner peripheral end portion. A closing seal is provided, and no short-circuit gas passage is formed in the gap under the action of the closing seal. Therefore, it is possible to reliably prevent the reaction gas supplied into the fuel cell from passing through the outer periphery of the electrode reaction surface and generating a so-called shortcut. As a result, it is possible to satisfactorily reduce reactive gas that is not used for power generation, and efficient and economical power generation is performed with a simple configuration.

  The closing seal is formed integrally with the inner peripheral end of the frame-shaped sealing surface and protrudes in a direction away from the first separator, and the mold pressing portion comes into contact with the first separator at the time of seal molding. The part (mold pressing surface) can be reliably closed by the closing seal. That is, after the sealing member having the closing seal is integrated with the first separator, when the entire fuel cell is clamped and held, the closing seal is deformed to the first separator side to close the mold holding surface. To do. This simplifies the manufacturing operation of the entire seal member and can satisfactorily close the short-circuit gas flow path.

  Further, the closing seal is a plurality of liquid seals or a plurality of solid seals filled in a gap between the inner peripheral end of the frame-shaped seal surface and the convex portion of the reaction gas flow path, and an arbitrary portion of the gap. Can be reliably closed.

  Furthermore, the reactive gas flow path constitutes a meandering flow path having a folded portion. For this reason, it is possible to satisfactorily prevent leakage of reaction gas, that is, a shortcut, through the closing seal even in the folded portion where the pressure difference becomes large, and the power generation efficiency can be improved.

  FIG. 1 is an exploded perspective view of a main part of a power generation cell 12 constituting the fuel cell 10 according to the first embodiment of the present invention. FIG. 2 is a diagram in which a plurality of power generation cells 12 are stacked in the direction of arrow A. FIG. 2 is a cross-sectional explanatory view taken along the line II-II in FIG. 1 of the stacked fuel cell 10.

  As shown in FIG. 2, the fuel cell 10 has a plurality of power generation cells 12 stacked in the direction of arrow A, and end plates 14 a and 14 b are disposed at both ends in the stacking direction. The end plates 14a and 14b are fixed via tie rods (not shown), whereby a predetermined tightening load is applied to the stacked power generation cells 12 in the arrow A direction.

  As shown in FIG. 1, in the power generation cell 12, the electrolyte membrane / electrode structure 16 is sandwiched between an anode side metal separator (first separator) 18 and a cathode side metal separator (second separator) 20. . The anode-side metal separator 18 and the cathode-side metal separator 20 are made of, for example, a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, or a metal plate whose surface has been subjected to anticorrosion treatment. Is set within a range of 0.05 mm to 1.0 mm, for example.

  One end edge of the power generation cell 12 in the direction of arrow B (horizontal direction in FIG. 1) communicates with each other in the direction of arrow A, which is the stacking direction, and discharges an oxidant gas (reactive gas) such as an oxygen-containing gas. An oxidant gas outlet communication hole 30b for discharging the cooling medium, a cooling medium outlet communication hole 32b for discharging the cooling medium, and a fuel gas (reactive gas), for example, a fuel gas inlet communication hole 34a for supplying a hydrogen-containing gas, Arranged upward in the direction of arrow C (vertical direction).

  The other end edge of the power generation cell 12 in the direction of arrow B communicates with each other in the direction of arrow A, the fuel gas outlet communication hole 34b for discharging the fuel gas, and the cooling medium inlet communication hole for supplying the cooling medium. 32a and an oxidant gas inlet communication hole 30a for supplying the oxidant gas are arranged in an upward direction in the direction of arrow C.

  The electrolyte membrane / electrode structure 16 includes, for example, a solid polymer electrolyte membrane 36 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode side electrode (first electrode) sandwiching the solid polymer electrolyte membrane 36. 38 and a cathode side electrode (second electrode) 40. The anode side electrode 38 has a smaller surface area than the cathode side electrode 40.

  The anode side electrode 38 and the cathode side electrode 40 are uniformly coated on the surface of the gas diffusion layer with a gas diffusion layer (not shown) made of carbon paper or the like, and porous carbon particles carrying a platinum alloy on the surface. And an electrode catalyst layer (not shown) formed. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 36.

  As shown in FIGS. 1 and 3, on the surface 20a of the cathode-side metal separator 20 that faces the electrolyte membrane / electrode structure 16, for example, an oxidant gas flow path that goes vertically downward while meandering in the arrow B direction. (Reactive gas flow path) 42 is provided. The oxidant gas channel 42 communicates with the oxidant gas inlet communication hole 30a and the oxidant gas outlet communication hole 30b.

  As shown in FIG. 4, a surface 18a of the anode-side metal separator 18 facing the electrolyte membrane / electrode structure 16 communicates with a fuel gas inlet communication hole 34a and a fuel gas outlet communication hole 34b as will be described later. Then, a fuel gas flow path (reactive gas flow path) 44 is formed in the vertical downward direction (arrow C direction) while meandering in the direction of arrow B.

  As shown in FIGS. 1 and 2, the surface 18b of the anode side metal separator 18 and the surface 20b of the cathode side metal separator 20 communicate with the cooling medium inlet communication hole 32a and the cooling medium outlet communication hole 32b. A cooling medium flow path 46 is formed. The cooling medium flow path 46 extends linearly in the direction of arrow B.

  As shown in FIGS. 1 and 3, the first seal member 50 is integrated with the surfaces 20 a and 20 b of the cathode side metal separator 20 around the outer peripheral end of the cathode side metal separator 20. For the first seal member 50, for example, a seal material such as EPDM, NBR, fluorine rubber, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroplane or acrylic rubber, a cushion material, or a packing material is used. It is done.

  As shown in FIGS. 2 and 3, the first seal member 50 is integrated with the first flat portion 52 integrated with the surface 20 a of the cathode side metal separator 20 and the surface 20 b of the cathode side metal separator 20. A second flat surface portion 54. The second plane part 54 is configured to be longer than the first plane part 52.

  As shown in FIG. 2, the first flat portion 52 circulates at a position spaced outside from the outer peripheral end of the electrolyte membrane / electrode structure 16, while the second flat portion 54 is an outer peripheral portion of the cathode-side electrode 40. Around the position where the polymerization is carried out over a predetermined range. As shown in FIG. 3, the first flat portion 52 is formed by connecting the oxidant gas inlet communication hole 30 a and the oxidant gas outlet communication hole 30 b to the oxidant gas flow path 42, while the second flat portion 54. Is formed by communicating the cooling medium inlet communication hole 32a and the cooling medium outlet communication hole 32b.

  As shown in FIGS. 1, 2, and 4, the second seal member 56 is integrated with the surfaces 18 a and 18 b of the anode side metal separator 18 around the outer peripheral end of the anode side metal separator 18. The The second seal member 56 includes an outer seal 58a provided on the surface 18a in the vicinity of the outer peripheral end of the anode side metal separator 18, and the inner seal 58b is spaced inward from the outer seal 58a by a predetermined distance. Is provided. In the second seal member 56, the outer seal 58 a and the inner seal 58 b constitute a frame-shaped seal surface that faces the anode side electrode 38.

  The outer seal 58a and the inner seal 58b can be selected from various cross-sectional shapes such as a tapered tip shape, a trapezoidal shape, or a bowl shape. The outer seal 58a is in contact with the first flat portion 52 provided on the cathode side metal separator 20, while the inner seal 58b is in direct contact with the solid polymer electrolyte membrane 36 constituting the electrolyte membrane / electrode structure 16. .

  As shown in FIG. 4, the outer seal 58a includes an oxidant gas inlet communication hole 30a, a cooling medium inlet communication hole 32a, a fuel gas outlet communication hole 34b, a fuel gas inlet communication hole 34a, a cooling medium outlet communication hole 32b, and an oxidant. The gas outlet communication hole 30b is surrounded. The inner seal 58b surrounds the fuel gas flow path 44, and an outer peripheral end portion of the electrolyte membrane / electrode structure 16 is disposed between the inner seal 58b and the outer seal 58a.

  As shown in FIG. 2, a plurality of closing seals 60 are formed in the gap between the inner peripheral end portion of the inner seal 58b and the convex portion 44a of the fuel gas channel 44 adjacent to the inner peripheral end portion. As will be described later, the closing seal 60 is formed integrally with the inner peripheral end portion of the inner seal 58b, protrudes in a direction away from the anode-side metal separator 18, and protrudes at both ends and the center in the longitudinal direction. A portion 60a is formed (see FIG. 4).

  The closing seal 60 has a function of preventing a so-called shortcut that the fuel gas passes through the outer periphery of the anode side electrode 38 without flowing through the meandering fuel gas flow path 44. Various numbers, shapes (width dimensions), and arrangement positions of the respective sealing seals 60 are set in accordance with portions where the fuel gas is actually likely to leak.

  An outer seal 58c corresponding to the outer seal 58a and an inner seal 58d corresponding to the inner seal 58b are provided on the surface 18b of the anode side metal separator 18 (see FIGS. 1 and 2). The outer seal 58c and the inner seal 58d have the same shape as the outer seal 58a and the inner seal 58b.

  As shown in FIG. 4, the outer seal 58 a includes a plurality of receiving portions 64 for forming a communication path that communicates the oxidant gas inlet communication hole 30 a and the oxidant gas flow path 42, and an oxidant gas outlet communication hole 30 b. A plurality of receiving portions 66 for forming a communication path communicating with the oxidant gas flow path 42 are provided.

  As shown in FIGS. 1 and 4, the surface 18b of the anode-side metal separator 18 has a plurality of receiving portions 68 for forming a communication path that communicates the cooling medium inlet communication hole 32a and the cooling medium flow path 46, and the cooling medium. A plurality of receiving portions 70 for forming a communication path that communicates the outlet communication hole 32b and the cooling medium flow path 46 are provided. A plurality of receiving portions 72 and 74 are provided on the surface 18b in the vicinity of the fuel gas inlet communication hole 34a and the fuel gas outlet communication hole 34b, respectively.

  As shown in FIG. 1, a plurality of supply hole portions 76 and discharge hole portions 78 are formed in the vicinity of the receiving portions 72 and 74, respectively, outside the inner seal 58 d. The supply hole portion 76 and the discharge hole portion 78 are formed through the surface 18a of the anode side metal separator 18 inward of the inner seal 58b and corresponding to the inlet side and the outlet side of the fuel gas passage 44 (see FIG. 4).

  Next, the operation of assembling the fuel cell 10 will be described below.

  The second seal member 56 is integrated with the anode side metal separator 18, while the first seal member 50 is integrated with the cathode side metal separator 20. In that case, in the anode side metal separator 18, the fuel gas flow path 44 and the cooling medium flow path 46 are formed in both surfaces 18a and 18b by press work.

  First, as shown in FIG. 5, the anode side metal separator 18 is disposed in a seal molding die 80. The mold 80 includes a first mold 82 and a second mold 84, and a cavity 86 and a relief 88 are formed between the first and second molds 82 and 84. The escape 88 accommodates the wave-shaped portions constituting the fuel gas flow path 44 and the cooling medium flow path 46. Between the relief 88 and the cavity 86, mold pressing portions 82a and 84a that are in contact with the anode-side metal separator 18 are provided over a distance H1.

  The cavity 86 corresponds to the shape of the second seal member 56, and a protruding cavity 86 a corresponding to the shape of the closing seal 60 communicates with the inner end (projection 44 a side) end of the cavity 86. The cavity 86a is provided in the second mold 84 and is inclined by an angle θ ° (30 ° <θ ° <60 °) in a direction away from the surface 18a of the anode side metal separator 18. The length H2 of the cavity 86a is set to a dimension having a desired closing function with the closing seal 60 covering the vicinity of the convex portion 44a.

  Therefore, the molten rubber is filled into the cavities 86 and 86a in a state where the first and second molds 82 and 84 are clamped with the anode-side metal separator 18 interposed therebetween. Therefore, after a predetermined time has elapsed, the second seal member 56 is integrated with the surfaces 18 a and 18 b of the anode side metal separator 18, and the inner periphery of the inner seal 58 b that constitutes the second seal member 56. A closing seal 60 is integrally formed at the end so as to incline in a direction away from the anode-side metal separator 18.

  Further, the first and second molds 82 and 84 are opened, and the anode side metal separator 18 is released from the mold 80. On the other hand, in the cathode side metal separator 20, the first seal member 50 is integrated with both surfaces 20 a and 20 b of the cathode side metal separator 20 through a seal molding die (not shown).

  Next, the anode-side metal separator 18 and the cathode-side metal separator 20 are disposed with the electrolyte membrane / electrode structure 16 therebetween, and are pressed in the stacking direction (arrow A direction). Therefore, as shown in FIG. 2, the closing seal 60 swings toward the surface 18a of the anode side metal separator 18, and the fuel gas flow path adjacent to the inner peripheral end of the inner seal 58b and the inner peripheral end. The gap between the convex portion 44a of 44 is closed. As a result, the power generation cell 12 is configured, and the fuel cell 10 is assembled by being stacked in a predetermined direction while being stacked in a predetermined number.

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

  First, as shown in FIG. 1, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet communication hole 30a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 34a. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the cooling medium inlet communication hole 32a.

  Therefore, the oxidant gas is introduced from the oxidant gas inlet communication hole 30a into the oxidant gas flow path 42 of the cathode-side metal separator 20 (see FIGS. 1 and 3), and vertically downward while meandering in the arrow B direction. To the cathode side electrode 40 of the electrolyte membrane / electrode structure 16. On the other hand, the fuel gas is introduced from the fuel gas inlet communication hole 34a through the supply hole 76 into the fuel gas flow path 44 of the anode side metal separator 18 (see FIG. 4). The fuel gas moves vertically downward while meandering in the direction of arrow B along the fuel gas flow path 44, and is supplied to the anode side electrode 38 of the electrolyte membrane / electrode structure 16 (see FIG. 1).

  Accordingly, in each electrolyte membrane / electrode structure 16, the oxidant gas supplied to the cathode side electrode 40 and the fuel gas supplied to the anode side electrode 38 are consumed by an electrochemical reaction in the electrode catalyst layer. Power generation is performed.

  Next, the oxidant gas consumed by being supplied to the cathode side electrode 40 is discharged in the direction of arrow A along the oxidant gas outlet communication hole 30b. Similarly, the fuel gas consumed by being supplied to the anode side electrode 38 passes through the discharge hole 78 and is discharged in the direction of arrow A along the fuel gas outlet communication hole 34b.

  The cooling medium supplied to the cooling medium inlet communication hole 32 a is introduced into the cooling medium flow path 46 between the anode side metal separator 18 and the cathode side metal separator 20 and then flows in the direction of arrow B. The cooling medium is discharged from the cooling medium outlet communication hole 32b after the electrolyte membrane / electrode structure 16 is cooled (see FIG. 1).

  In this case, in the first embodiment, the second seal member 56 provided on the anode side metal separator 18 has a plurality of closing seals 60 integrated with the inner peripheral end of the inner seal 58b. . The closing seal 60 closes the gap between the inner peripheral end portion of the inner seal 58b and the convex portion 44a of the fuel gas channel 44 adjacent to the inner peripheral end portion.

  For this reason, a short-circuit gas passage is not formed in the gap between the inner seal 58b and the convex portion 44a. Therefore, the fuel gas that is the reaction gas supplied into the fuel cell 10 is reliably prevented from passing through the outer periphery of the electrode reaction surface and generating a shortcut. As a result, it is possible to favorably reduce the fuel gas that is not used for power generation, and the effect is achieved that efficient and economical power generation is performed with a simple configuration.

  Further, the closing seal 60 is formed integrally with the inner peripheral end of the inner seal 58b. That is, when the second seal member 56 is manufactured, the inner seal 58b, the outer seal 58a, and the closing seal 60 can be formed at the same time, and the manufacturing operation of the entire second seal member 56 is effectively simplified. .

  Furthermore, the fuel gas channel 44 constitutes a meandering channel having a folded portion. For this reason, it is possible to satisfactorily prevent the fuel gas from leaking, that is, the shortcut, through the closing seal 60 even in the folded portion where the pressure difference becomes large.

  The closing seal 60 is formed integrally with the inner peripheral end of the inner seal 58b and protrudes away from the surface 18a of the anode side metal separator 18. Therefore, as shown in FIG. 5, the mold pressing surface where the mold pressing portion 84 a contacts the anode-side metal separator 18 at the time of seal molding can be reliably closed by the closing seal 60.

  That is, after the second seal member 56 having the closing seal 60 is integrated with the anode side metal separator 18, the closing seal 60 is attached to the surface of the anode side metal separator 18 when the entire fuel cell 10 is clamped and held. The mold pressing surface is closed by deforming to the 18a side. This simplifies the manufacturing operation of the entire second seal member 56 and can close the short-circuit gas flow path satisfactorily.

  FIG. 6 is an explanatory cross-sectional view of a fuel cell 90 according to the second embodiment of the present invention. The same components as those of the fuel cell 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Similarly, detailed descriptions of third and fourth embodiments described below are omitted.

  Each power generation cell 92 constituting the fuel cell 90 includes an anode side metal separator 94, and a second seal member 96 is integrated with the surfaces 94 a and 94 b of the anode side metal separator 94. The second seal member 96 includes an outer seal 58a and an inner seal 58b provided on the surface 94a, and a plurality of closing seals 98 are provided in a gap between the inner peripheral end of the inner seal 58b and the convex portion 44a. (See FIGS. 6 and 7). The closing seal 98 is configured separately from the second seal member 96, and is formed in advance in a line shape, and is preferably formed of the same material as the second seal member 96.

  In the second embodiment configured as described above, the fuel gas supplied into the fuel cell 90 can be reliably prevented from passing through the outer periphery of the electrode reaction surface by shortcutting the fuel gas passage 44. The same effects as those of the first embodiment can be obtained, such as efficient and economical power generation with a simple configuration.

  FIG. 8 is an explanatory cross-sectional view of a fuel cell 100 according to the third embodiment of the present invention.

  Each power generation cell 102 constituting the fuel cell 100 includes an anode side metal separator 104, and a second seal member 106 is integrated with the surfaces 104 a and 104 b of the anode side metal separator 104. The second seal member 106 includes an outer seal 58a and an inner seal 58b provided on the surface 104a, and a plurality of liquid seals (blocking seals) 108 are disposed at predetermined positions in the gap between the inner seal 58b and the convex portion 44a. (See FIG. 8 and FIG. 9).

  When providing the liquid seal 108, first, as shown in FIG. 10, the anode-side metal separator 104 and the cathode-side metal separator 20 are arranged apart from each other, and the gap between the inner seal 58b and the convex portion 44a. The liquid seal 108 is applied to the substrate. Next, as shown in FIG. 11, after the anode-side metal separator 104 and the cathode-side metal separator 20 have moved in directions close to each other, the fuel cell 100 is subjected to a pressing process in the stacking direction.

  At this time, as shown in FIG. 8, the cross-sectional area S1 of the liquid seal 108 in a state where a load during use is applied to the fuel cell 10 is the application cross-sectional area of the liquid seal 108 before the fuel cell 10 is assembled. It is set smaller than S2 (see FIG. 9) (S1 <S2).

  As a result, the liquid seal 108 is cured in a state where a press load corresponding to the load during use is applied, so that the liquid seal 108 is reliably filled in the gap between the inner seal 58b and the convex portion 44a and closed. A high-rate closure seal is constructed (see FIG. 8). Therefore, in the third embodiment, the same effects as in the first and second embodiments can be obtained, such as efficient power generation with a simple configuration.

  FIG. 12 is an exploded perspective view of the main part of the power generation cell 122 constituting the fuel cell 120 according to the fourth embodiment of the present invention.

  The power generation cell 122 includes an electrolyte membrane / electrode structure 124, an anode side metal separator 126, and a cathode side metal separator 128. The electrolyte membrane / electrode structure 124 includes a solid polymer electrolyte membrane 36a provided with communication holes such as an oxidant gas inlet communication hole 30a, and an anode side electrode 38a and a cathode side electrode that sandwich the solid polymer electrolyte membrane 36a. 40a. The anode side electrode 38a and the cathode side electrode 40a are set to have substantially the same surface area (see FIG. 13).

  The first seal member 130 is integrated with the surfaces 128 a and 128 b of the cathode side metal separator 128 around the outer peripheral end of the cathode side metal separator 128. The first seal member 130 includes a frame-shaped seal surface 132 provided on the surface 128a side and in direct contact with the solid polymer electrolyte membrane 36a. A plurality of closing seals 60 are formed in the gap between the inner peripheral end portion of the frame-shaped seal surface 132 and the convex portion 42a of the oxidant gas flow channel 42 adjacent to the inner peripheral end portion.

  The second seal member 134 is integrated with the surfaces 126 a and 126 b of the anode side metal separator 126 around the outer peripheral end of the anode side metal separator 126. The second seal member 134 is provided on the surface 126a and directly contacts the solid polymer electrolyte membrane 36a, and the first seal member 130 of the cathode side metal separator 128 is provided on the surface 126b. And a second frame-like sealing surface 138 in contact with. A plurality of closing seals 60 are formed in the gap between the inner peripheral end portion of the first frame-shaped seal surface 136 and the convex portion 44a of the fuel gas channel 44 adjacent to the inner peripheral end portion.

  In the fourth embodiment configured as described above, the electrolyte membrane / electrode structure 124 is sandwiched between the anode side metal separator 126 and the cathode side metal separator 128. At that time, the frame-shaped seal surface 132 and the first frame-shaped seal surface 136 of the first and second seal members 130 and 134 sandwich the solid polymer electrolyte membrane 36a of the electrolyte membrane / electrode structure 124, and Each of the first and second seal members 130 and 134 is provided with a plurality of closing seals 60.

  Here, the closing seal 60 includes a gap between the inner peripheral end of the frame-shaped seal surface 132 and the convex portion 42a of the oxidant gas flow path 42 adjacent to the inner peripheral end, and the first frame-shaped seal surface 136. The gaps between the inner peripheral end and the convex portion 44a of the fuel gas channel 44 adjacent to the inner peripheral end are closed (see FIG. 13).

  Therefore, the oxidant gas and the fuel gas, which are the reaction gases supplied into the fuel cell 120, are reliably prevented from passing through the outer periphery of the electrode reaction surface and a shortcut is generated. The same effects as those of the first to third embodiments are obtained, such as economical power generation.

  In the fourth embodiment, the same closing seal 60 as that in the first embodiment is used. However, the present invention is not limited to this, and the closing seal 98 in the second embodiment and the third embodiment are not limited thereto. Alternatively, the liquid seal 108 or the like may be used.

It is a principal part disassembled perspective explanatory drawing of the electric power generation cell which comprises the fuel cell which concerns on the 1st Embodiment of this invention. FIG. 2 is a sectional view of the fuel cell taken along line II-II in FIG. 1. It is front explanatory drawing of the cathode side metal separator which comprises the said fuel cell. It is front explanatory drawing of the anode side metal separator which comprises the said fuel cell. It is explanatory drawing of the metal mold | die which integrates a 2nd sealing member with the said anode side metal separator. It is a cross-sectional explanatory view of a fuel cell according to a second embodiment of the present invention. It is front explanatory drawing of the anode side metal separator which comprises the said fuel cell. It is a section explanatory view of a fuel cell concerning a 3rd embodiment of the present invention. It is front explanatory drawing of the anode side metal separator which comprises the said fuel cell. It is explanatory drawing at the time of apply | coating a liquid seal between the said anode side metal separator and a cathode side metal separator. It is explanatory drawing at the time of clamping the said liquid seal with the said anode side metal separator and the said cathode side metal separator. It is a principal part disassembled perspective explanatory view of the electric power generation cell which constitutes the fuel cell concerning a 4th embodiment of the present invention. FIG. 13 is a sectional view taken along line XIII-XIII in FIG. 12 of the fuel cell. It is front explanatory drawing of the anode side metal separator which comprises the said fuel cell. It is explanatory drawing of the seal structure disclosed by patent document 1. FIG.

Explanation of symbols

10, 90, 100, 120 ... Fuel cells 12, 92, 102, 122 ... Power generation cells 16, 124 ... Electrolyte membrane / electrode structures 18, 94, 104, 126 ... Anode side metal separators 20, 128 ... Cathode side metal separators 30a ... Oxidant gas inlet communication hole 30b ... Oxidant gas outlet communication hole 32a ... Cooling medium inlet communication hole 32b ... Cooling medium outlet communication hole 34a ... Fuel gas inlet communication hole 34b ... Fuel gas outlet communication hole 36, 36a ... Solid height Molecular electrolyte membrane 38, 38a ... anode side electrode 40, 40a ... cathode side electrode 42 ... oxidant gas passage 44 ... fuel gas passage 46 ... cooling medium passage 50, 56, 96, 106, 130, 134 ... sealing member 52, 54... Flat portions 58a, 58c... Outer seals 58b, 58d... Inner seals 60, 98. 70, 72, 74 ... receiving section 76 ... supply hole section 78 ... discharge hole section 80 ... mold 82, 84 ... mold 86, 86a ... cavity 108 ... liquid seal 132, 136, 138 ... frame-shaped seal surface

Claims (5)

An electrolyte membrane / electrode structure having a first electrode and a second electrode disposed on both sides of the electrolyte membrane, the electrolyte membrane / electrode structure being disposed between the first and second separators; The first and second separators are fuel cells in which a reaction gas flow path for supplying a predetermined reaction gas along the first and second electrodes is formed, respectively.
At least the first separator is provided with a seal member so as to cover the outer peripheral edge of the first separator, and the seal member has a frame-like seal surface facing the first electrode,
In the gap between the inner peripheral end of the frame-shaped sealing surface and the convex portion of the reaction gas flow channel adjacent to the inner peripheral end, a plurality of reaction gases are prevented from flowing along the gap. A fuel cell, characterized in that a closure seal is provided.   2. The fuel cell according to claim 1, wherein the closing seal is integrally formed at an inner peripheral end of the frame-shaped sealing surface and protrudes in an inclined direction away from the first separator. Fuel cell.   2. The fuel cell according to claim 1, wherein the closing seal is a plurality of liquid seals filled in a gap between an inner peripheral end portion of the frame-shaped seal surface and a convex portion of the reaction gas flow path. Fuel cell.   2. The fuel cell according to claim 1, wherein the closing seal is a plurality of solid seals disposed in a gap between an inner peripheral end portion of the frame-shaped seal surface and a convex portion of the reaction gas flow path. A fuel cell. 5. The fuel cell according to claim 1, wherein the first and second separators face a reaction gas flow path for supplying a reaction gas to the first and second electrodes, respectively. 6. Along the direction,
The fuel cell according to claim 1, wherein the reaction gas flow path constitutes a meandering flow path having a folded portion.

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