JP2013171651A - Fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell having a simple configuration in which interference between a terminal for cell voltage measurement and a seal member is avoided and a cell voltage is made possible to be correctly measured.SOLUTION: In a fuel cell 10, a metal separator 12 and an electrolyte membrane/electrode structure 14 are laminated on each other. A resin frame member 22 is provided integrally in the electrolyte membrane/electrode structure 14. In the resin frame member 22, an outside seal member 44 is provided at an outer side than the contour line of the metal separator 12. A terminal 50 for cell voltage measurement is buried inside the outside seal member 44 and one end of a terminal plate 52 constituting the terminal 50 for cell voltage measurement is in contact with the adjacent metal separator 12 at an inner side than the outside seal member 44. On the other hand, the other end of the terminal plate 52 protrudes to the outer side from a side part of the resin frame member 22.

Description

  In the present invention, an electrolyte / electrode structure in which a pair of electrodes are disposed on both sides of an electrolyte and a metal separator are laminated, and an outer periphery of the electrolyte / electrode structure is larger than an outer dimension of the metal separator. The present invention relates to a fuel cell in which a resin frame member having an outer dimension is integrally provided.

  For example, a solid polymer fuel cell employs a solid polymer electrolyte membrane made of a polymer ion exchange membrane. In this fuel cell, an electrolyte membrane / electrode structure (electrolyte / electrode structure) (MEA) in which an electrode catalyst layer and an anode electrode made of porous carbon and a cathode electrode are disposed on both sides of a solid polymer electrolyte membrane, respectively. A power generation cell is configured by being sandwiched between separators (bipolar plates). Normally, a fuel cell stack in which a predetermined number of power generation cells are stacked is used as, for example, an in-vehicle fuel cell stack.

  In this type of fuel cell stack, in order to obtain a desired power generation performance, a predetermined number (for example, several tens to several hundreds) of power generation cells are stacked, and each power generation cell has a desired power generation performance. It is necessary to detect whether or not. For this reason, in general, a cell voltage measurement terminal provided on the separator is connected to a voltage detection device (cell voltage monitor) to detect a cell voltage for each power generation cell during power generation or for each predetermined power generation cell. Work is being done.

  For example, the fuel cell disclosed in Patent Document 1 includes a seal gasket-integrated MEA 1 as shown in FIG. The seal gasket-integrated MEA 1 includes a first MEA 1a and a second MEA 1b each having a rectangular shape, and a seal gasket 2 is disposed around the first MEA 1a and the second MEA 1b.

  A plurality of through holes 3 are formed in the seal gasket 2 in order to supply and discharge hydrogen gas, air, and cooling water, respectively. The seal gasket 2 is provided with a seal line SL that goes around the first MEA 1 a, the second MEA 1 b, and each through-hole 3, and a cell voltage monitor terminal 4 is embedded together with a terminal wire 5 at a corner of the seal gasket 2. . A part of the cell voltage monitoring terminal 4 is exposed from one surface of the seal gasket 2.

JP 2008-140722 A

  By the way, in the seal gasket-integrated MEA 1 described above, the cell voltage monitoring terminal 4 is provided outside the outer peripheral seal constituting the seal line SL. For this reason, a seal member is further required outside the cell voltage monitoring terminal 4, and there is a problem that the configuration becomes complicated.

  The present invention solves this type of problem, and provides a fuel cell capable of measuring the cell voltage accurately while avoiding interference between the cell voltage measurement terminal and the seal member with a simple configuration. The purpose is to provide.

  In the present invention, an electrolyte / electrode structure in which a pair of electrodes are disposed on both sides of an electrolyte and a metal separator are laminated, and an outer periphery of the electrolyte / electrode structure is larger than an outer dimension of the metal separator. The present invention relates to a fuel cell in which a resin frame member having an outer dimension is integrally provided.

  In this fuel cell, the resin frame member is provided with a seal member outward from the outline of the metal separator, and a cell voltage measurement terminal is embedded in the seal member, and the cell voltage measurement is performed. One end of the terminal for use is in contact with the adjacent metal separator inside the seal member, while the other end of the cell voltage measurement terminal protrudes outward from the side portion of the resin frame member.

  In this fuel cell, when the sealing member is molded into the resin frame member, it is preferable that a part of the cell voltage measurement terminal is embedded in the sealing member by insert molding.

  Furthermore, in this fuel cell, it is preferable that the cell voltage measuring terminal is insert-molded inside the seal member in a state where the outer periphery is covered with a rubber material.

  In the present invention, the cell voltage measurement terminal is embedded in the seal member, and one end of the cell voltage measurement terminal is in contact with the adjacent metal separator inside the seal member. Therefore, the cell voltage measurement terminal can be taken out of the resin frame member without straddling the contact surface between the seal member and the contact member, and a desired seal function can be ensured. In addition, the metal separator can be favorably downsized and easily reduced in weight and cost compared to a configuration in which the cell voltage measurement terminal is directly taken out from the metal separator.

It is a principal part disassembled perspective explanatory drawing of the fuel cell which concerns on the 1st Embodiment of this invention. It is the II-II sectional view taken on the line of the said fuel cell in FIG. It is front explanatory drawing of the metal separator which comprises the said fuel cell. It is a perspective explanatory view of a cell voltage measuring terminal. It is a perspective view of the terminal board which comprises the said cell voltage measurement terminal. It is explanatory drawing at the time of shape | molding the resin member and the rubber member to the said terminal board. It is explanatory drawing at the time of insert-molding the said terminal board to an outer side sealing member. It is a principal part disassembled perspective explanatory drawing of the fuel cell which concerns on the 2nd Embodiment of this invention. It is the IX-IX sectional view taken on the line of the said fuel cell in FIG. 2 is an explanatory diagram of a fuel cell disclosed in Patent Document 1. FIG.

  As shown in FIGS. 1 and 2, the fuel cell 10 according to the first embodiment of the present invention includes metal separators 12 and electrolyte membrane / electrode structures (electrolyte / electrode structures) (MEA) 14 alternately. Laminated.

  As shown in FIG. 2, the electrolyte membrane / electrode structure 14 includes, for example, a solid polymer electrolyte membrane 16 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode electrode sandwiching the solid polymer electrolyte membrane 16 18 and the cathode electrode 20. The anode electrode 18 and the cathode electrode 20 are formed by uniformly applying a gas diffusion layer (not shown) made of carbon paper or the like and porous carbon particles carrying a platinum alloy on the surface thereof to the surface of the gas diffusion layer. And an electrode catalyst layer (not shown) to be formed. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 16.

  The solid polymer electrolyte membrane 16 is set to have the same surface area as the anode electrode 18 and the cathode electrode 20 or a surface area larger than these. A resin frame member 22, which is a resin frame-like frame member, is integrally formed on the outer peripheral end of the solid polymer electrolyte membrane 16 by, for example, injection molding. As the resin material, for example, engineering plastics, super engineering plastics, etc. are adopted in addition to general-purpose plastics.

  As shown in FIG. 1, one end edge (upper edge) of the resin frame member 22 in the direction of arrow C communicates with each other in the direction of arrow A to supply an oxidant gas, for example, an oxygen-containing gas. An oxidant gas inlet communication hole 24a, a cooling medium inlet communication hole 26a for supplying a cooling medium, and a fuel gas inlet communication hole 28a for supplying a fuel gas, for example, a hydrogen-containing gas, are provided in an arrow B direction (horizontal direction). ).

  The other end edge (lower end edge) of the resin frame member 22 in the direction of arrow C communicates with each other in the direction of arrow A, the fuel gas outlet communication hole 28b for discharging the fuel gas, and for discharging the cooling medium. The cooling medium outlet communication holes 26b and the oxidant gas outlet communication holes 24b for discharging the oxidant gas are arranged in the arrow B direction.

  The outer peripheral end of the metal separator 12 has an oxidant gas inlet communication hole 24a, a cooling medium inlet communication hole 26a, a fuel gas inlet communication hole 28a, a fuel gas outlet communication hole 28b, a cooling medium outlet communication hole 26b, and an oxidant gas outlet communication. It arrange | positions inside the hole 24b.

  The metal separator 12 is made of, for example, a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, or a thin plate-like metal plate whose surface is subjected to anticorrosion treatment. As shown in FIGS. 1 and 2, the metal separator 12 faces the anode separator surface 32 facing the anode electrode 18 of the electrolyte membrane / electrode structure 14 and the cathode electrode 20 of the electrolyte membrane / electrode structure 14. And a cathode separator surface 34.

  As shown in FIG. 3, a fuel gas flow path 36 having a corrugated cross section is formed on the anode separator surface 32 of the metal separator 12 by pressing into a wave shape. The fuel gas channel 36 extends in the direction of arrow C, and causes the fuel gas to flow from the vertically upward direction to the vertically downward direction.

  As shown in FIG. 1, the metal separator 12 is formed into an oxidant gas flow path 38 having a corrugated cross section by pressing into a wave shape on the cathode separator surface 34. The oxidant gas flow path 38 causes the oxidant gas to flow in the direction of arrow C. A plurality of cooling medium supply holes 40 a and cooling medium discharge holes 40 b are formed on the upper and lower sides of the oxidant gas flow path 38 on the cathode separator surface 34.

  Inside the metal separator 12, a cooling medium flow path 42 is formed which communicates with the cooling medium supply hole 40 a and the cooling medium discharge hole 40 b and distributes the cooling medium in the direction of arrow C. The cooling medium flow path 42 is configured by an overlapping shape of the back surface shape of the fuel gas flow channel 36 and the back surface shape of the oxidant gas flow channel 38.

  As shown in FIG. 1, an outer seal member (outer seal line) 44 and an inner seal member (inner seal line) 46 are integrally formed on the surface of the resin frame member 22 on the fuel gas flow path 36 side. The outer seal member 44 and the inner seal member 46 include, for example, EPDM, NBR, fluorine rubber, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene or acrylic rubber, a cushion material, or A packing material is used.

  The outer seal member 44 surrounds the outer side of the outline of the metal separator 12, and the oxidant gas inlet communication hole 24 a, the coolant inlet communication hole 26 a, the fuel gas inlet communication hole 28 a, and the oxidation are all fluid communication holes. The outer periphery of the agent gas outlet communication hole 24b, the cooling medium outlet communication hole 26b, and the fuel gas outlet communication hole 28b and the outer periphery of the reaction surface (power generation surface) are circulated.

  The inner seal member 46 is located inside the outer seal member 44 and is provided along a contour line corresponding to the outer shape of the metal separator 12, and the entire outer peripheral edge surface of the metal separator 12 (within the separator surface). ) The inner seal member 46 communicates the fuel gas inlet communication hole 28a and the fuel gas outlet communication hole 28b to the fuel gas flow path 36, the oxidant gas inlet communication hole 24a, the cooling medium inlet communication hole 26a, and the cooling medium outlet communication hole. 26 b and the oxidant gas outlet communication hole 24 b circulate and shield from the fuel gas flow path 36.

  Although not shown, the oxidant gas inlet communication hole 24a and the oxidant gas outlet communication hole 24b communicate with the oxidant gas flow path 38 on the surface of the resin frame member 22 on the fuel gas flow path 36 side, and the cooling medium inlet. A seal portion is provided that goes around the communication hole 26a, the fuel gas inlet communication hole 28a, the fuel gas outlet communication hole 28b, and the cooling medium outlet communication hole 26b and shields it from the oxidant gas flow path 38.

  As shown in FIGS. 2 and 4, in the outer seal member 44, for example, a cell voltage measurement terminal 50 is embedded in a portion extending along one long side of the resin frame member 22. . The cell voltage measuring terminal 50 includes a thin plate-like conductive terminal plate 52.

  One end of the terminal plate 52 is located on the inner side of the outer seal member 44 and is exposed on the surface of the resin frame member 22, and has an exposed portion 52a that contacts the adjacent metal separator 12 (anode separator surface 32) (FIG. 2). reference). Although the back surface of the exposed portion 52 a is in contact with the inner seal member 46, the back surface may not be in contact with the inner seal member 46 as long as the exposed portion 52 a is in contact with the metal separator 12. The other end of the terminal plate 52 has a tip exposed portion 52 b that protrudes outward from the resin frame member 22.

  The cell voltage measuring terminal 50 is integrally provided with a resin member 54 that protrudes outward from the outer periphery of the resin frame member 22, and covers one end edge of the terminal plate 52 from a part of the resin member 54, and a rubber member 55. Is formed. At one end of the terminal board 52, the exposed portion 52 a is exposed from the end position of the rubber member 55.

  As shown in FIG. 2, a sealing member 56 is mounted on the front end side of the cell voltage measuring terminal 50 and is covered with a resin member 54, and a connector 58 is connectable. The connector 58 has a U-shaped connection terminal portion 62 accommodated in the casing 60. The connection terminal portion 62 is in electrical contact with the tip exposed portion 52b and is connected to a cell voltage measurement device (not shown).

  Next, the operation of integrating the cell voltage measurement terminal 50 with the resin frame member 22 will be described below.

  First, as shown in FIG. 5, a terminal plate 52 constituting the cell voltage measuring terminal 50 is prepared. The terminal plate 52 is formed by bending a flat metal into a predetermined shape. As shown in FIG. 6, after the resin member 54 is integrally formed on the terminal plate 52, a rubber member 55 is formed so as to cover one end edge of the terminal plate 52 from a part of the resin member 54.

  Further, as shown in FIG. 7, the resin frame member 22 is provided with a groove 22a for molding the outer seal member 44, and the terminal plate 52 has a part of the rubber member 55 straddling the groove 22a. It is arranged with.

  The resin frame member 22 is formed with an outer seal member 44 along the groove portion 22a and with an inner seal member 46 along a groove portion (not shown). In that case, the terminal board 52 is arrange | positioned ranging over the groove part 22a, and a part of said terminal board 52 is embed | buried inside the outer side sealing member 44 (insert molding).

  Next, the resin frame member 22 is integrated with the outer peripheral edge portions of the solid polymer electrolyte membrane 16, the anode electrode 18, and the cathode electrode 20, whereby the electrolyte membrane / electrode structure 14 is manufactured.

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

  As shown in FIG. 1, an oxidant gas such as an oxygen-containing gas supplied to the oxidant gas inlet communication hole 24 a is supplied to the oxidant gas flow path 38 of the metal separator 12. The oxidant gas flows in the direction of arrow C along the cathode electrode 20 of the electrolyte membrane / electrode structure 14, and then is discharged to the oxidant gas outlet communication hole 24b.

  On the other hand, the fuel gas such as the hydrogen-containing gas supplied to the fuel gas inlet communication hole 28 a is supplied to the fuel gas flow path 36 of the metal separator 12. The fuel gas flows in the direction of arrow C along the anode electrode 18 of the electrolyte membrane / electrode structure 14, and then is discharged to the fuel gas outlet communication hole 28b.

  Therefore, in the electrolyte membrane / electrode structure 14, the oxidant gas supplied to the cathode electrode 20 and the fuel gas supplied to the anode electrode 18 are consumed by an electrochemical reaction in the electrode catalyst layer to generate power. Is called.

  Further, the cooling medium such as pure water, ethylene glycol, or oil supplied to the cooling medium inlet communication hole 26 a passes through the plurality of cooling medium supply holes 40 a formed on the cathode separator surface 34 constituting the metal separator 12. It is introduced inside the metal separator 12.

  A cooling medium flow path 42 is formed inside the metal separator 12. Therefore, the cooling medium flows in the direction of arrow C along the cooling medium flow path 42, and is then discharged from the plurality of cooling medium discharge holes 40b to the cooling medium outlet communication hole 26b (see FIG. 1).

  In this case, in the first embodiment, as shown in FIG. 2, the cell voltage measurement terminal 50 is embedded in the outer seal member 44 and the terminal plate 52 constituting the cell voltage measurement terminal 50. Is in contact with the adjacent metal separator 12 inside the outer seal member 44. On the other hand, the exposed end portion 52 b of the terminal plate 52 protrudes outward from the side portion of the resin frame member 22.

  Therefore, the cell voltage measurement terminal 50 can be taken out of the resin frame member 22 without straddling the contact surface between the outer seal member 44 serving as a seal line and the resin frame member 22 (contact member). It is possible to obtain an effect that a desired sealing function can be ensured.

  In addition, the metal separator 12 can be reduced in size and the weight and cost can be easily reduced as compared with the configuration in which the cell voltage measurement terminal 50 is directly taken out from the metal separator 12.

  FIG. 8 is an exploded perspective view of the main part of the fuel cell 100 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.

  As shown in FIGS. 8 and 9, the fuel cell 100 includes an electrolyte membrane / electrode structure 14, a metal separator 12, and a cell unit in which the electrolyte membrane / electrode structure 14 and the metal separator 102 are stacked.

  The metal separator 102 is composed of a single metal plate, and is provided with a fuel gas flow path 36 facing the anode electrode 18 of one electrolyte membrane / electrode structure 14 and the other electrolyte membrane / electrode structure 14. An oxidant gas flow path 38 is provided facing the cathode electrode 20. Each fuel cell 100 does not have a cooling medium flow path between the pair of electrolyte membrane / electrode structures 14 with the metal separator 102 interposed therebetween, and adopts a so-called thinning cooling structure.

  As shown in FIG. 9, the cell voltage measurement terminal 50 includes a thin plate-like conductive terminal plate 104 partially embedded in the outer seal member 44. One end of the terminal plate 104 has an exposed portion 104 a that is located inside the outer seal member 44 and contacts the adjacent metal separator 102. The other end of the terminal plate 104 has a tip exposed portion 104 b that protrudes outward from the side portion of the resin frame member 22.

  In the fuel cell 100 configured as described above, the terminal plate 104 is partially embedded in the outer seal member 44, and the exposed portion 104 a of the terminal plate 104 is located inward of the outer seal member 44. Located and in contact with the adjacent metal separator 102.

  Therefore, the cell voltage measurement terminal 50 can be taken out of the resin frame member 22 without straddling the contact surface between the outer seal member 44 that is a seal line and the contact portion. Therefore, the same effects as those of the first embodiment can be obtained, such as ensuring a desired sealing function. In addition, although the double seal | sticker of the outer side seal member 44 and the inner side seal member 46 is employ | adopted for the seal line, it is not limited to this.

DESCRIPTION OF SYMBOLS 10,100 ... Fuel cell 12, 102 ... Metal separator 14 ... Electrolyte membrane and electrode structure 16 ... Solid polymer electrolyte membrane 18 ... Anode electrode 20 ... Cathode electrode 22 ... Resin frame member 22a ... Groove part 24a ... Oxidant gas inlet communication Hole 24b ... Oxidant gas outlet communication hole 26a ... Cooling medium inlet communication hole 26b ... Cooling medium outlet communication hole 28a ... Fuel gas inlet communication hole 28b ... Fuel gas outlet communication hole 36 ... Fuel gas flow path 38 ... Oxidant gas flow path 42 ... Cooling medium flow path 44 ... Outer seal member 46 ... Inner seal member 50 ... Cell voltage measuring terminals 52, 104 ... Terminal plate 52a, 104a ... Exposed portion 52b, 104b ... End exposed portion 54 ... Resin member

Claims (3)

An electrolyte / electrode structure having a pair of electrodes disposed on both sides of the electrolyte and a metal separator are stacked, and the outer periphery of the electrolyte / electrode structure has an outer dimension larger than the outer dimension of the metal separator. A fuel cell in which a resin frame member is provided integrally,
The resin frame member is provided with a seal member outside the outer shape line of the metal separator,
A cell voltage measuring terminal is embedded in the seal member,
One end of the cell voltage measurement terminal is in contact with the adjacent metal separator inside the seal member, while the other end of the cell voltage measurement terminal is outward from the side of the resin frame member. A fuel cell characterized by protruding.   2. The fuel cell according to claim 1, wherein when the sealing member is molded into the resin frame member, a part of the cell voltage measuring terminal is embedded in the sealing member by insert molding. Fuel cell.   3. The fuel cell according to claim 1, wherein the cell voltage measuring terminal is insert-molded inside the seal member in a state in which a rubber material is coated on an outer periphery. 4.

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