JP2015146230A - fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately and reliably position a separator and an electrolyte membrane-electrode structure with a frame, in a simple and economical constitution.SOLUTION: A power generation unit 12 constituting a fuel cell 10 holds an electrolyte membrane-electrode structure 14 with a frame by a cathode side separator 16 and an anode side separator 18. A resin body 50a is provided on an outer periphery of a resin frame member 50, the resin body being cured integrally with the resin frame member 50 at a molten resin material supply port in molding, while recessed portions 46br, 46cr for positioning, to which the resin body 50a is fit, are provided in the anode side separator 18.

Description

  The present invention has an electrolyte membrane / electrode structure in which electrodes are respectively disposed on both sides of a solid polymer electrolyte membrane, and has a frame in which a resin frame member is provided around the outer periphery of the electrolyte membrane / electrode structure The present invention relates to a fuel cell in which an electrolyte membrane / electrode structure and a separator are stacked.

  In general, a polymer electrolyte fuel cell employs a polymer electrolyte membrane made of a polymer ion exchange membrane. This fuel cell includes an electrolyte membrane / electrode structure (MEA) in which an anode electrode is disposed on one side of a solid polymer electrolyte membrane and a cathode electrode is disposed on the other side of the solid polymer electrolyte membrane. . The electrolyte membrane / electrode structure is sandwiched between separators (bipolar plates) to constitute a fuel cell. This fuel cell is mounted on a fuel cell electric vehicle as, for example, an in-vehicle fuel cell stack by stacking a predetermined number of fuel cells.

  In a fuel cell, normally, several tens to several hundreds of fuel cells are stacked to constitute a fuel cell stack. At that time, it is necessary to accurately position between the MEA and the separator constituting the fuel cell and between the fuel cells. For example, a method for manufacturing a polymer electrolyte fuel cell disclosed in Patent Document 1 is known. ing.

  In this manufacturing method, the anode side gasket is provided with a protrusion that can be elastically deformed, and the protrusion protrudes toward the inside of the gasket. The gasket is attached to the separator, and when the MEA is placed on the separator, the anode is fitted inside the gasket while compressively deforming the protruding portion. Thereby, the anode is arranged in the inner region of the gasket.

  The cathode side gasket is provided with an elastically deformable protrusion, and the protrusion protrudes toward the inside of the gasket. The gasket is attached to the separator, and when the MEA is placed on the separator, the cathode is fitted inside the gasket while compressing and deforming the protruding portion. For this reason, the cathode is arranged in the inner region of the gasket. As a result, the MEA can be easily positioned in each cell.

JP 2006-324170 A

  By the way, in the above-mentioned Patent Document 1, each of the gaskets on the anode side and the cathode side is provided with elastically deformable protrusions, so that the manufacturing work of the gasket becomes complicated and the manufacturing cost increases. .

  In addition, the anode and the cathode are arranged in the inner region of the gasket while compressively deforming the elastically deformable protrusion. Therefore, the positioning accuracy of the anode and the cathode is lowered, and it may be difficult to accurately position the MEA with respect to the separator.

  The present invention solves this type of problem and provides a fuel cell capable of accurately and reliably positioning a framed electrolyte membrane / electrode structure and a separator with a simple and economical configuration. For the purpose.

  The fuel cell according to the present invention has an electrolyte membrane / electrode structure in which electrodes are respectively disposed on both sides of a solid polymer electrolyte membrane, and a resin frame member circulates around the outer periphery of the electrolyte membrane / electrode structure. A framed electrolyte membrane / electrode structure is provided. The electrolyte membrane / electrode structure with a frame is laminated with a separator to constitute a fuel cell.

  In this fuel cell, a resin body hardened integrally with the resin frame member at the molten resin material supply port at the time of molding is provided on the outer periphery of the resin frame member. On the other hand, the separator is provided with a positioning recess into which the resin body is fitted.

  Further, in this fuel cell, the recess is preferably provided by cutting out a seal member integrally formed with the separator.

  Furthermore, in this fuel cell, it is preferable that the separator is provided with a fuel gas flow path through which the fuel gas flows along one separator surface. The seal member has an inner seal that circulates in the fuel gas flow path and contacts the resin frame member, and an outer seal that circulates outward of the resin frame member, and a resin body is fitted to the outer seal. It is preferable that a concave portion is formed.

  According to the present invention, the resin frame member is integrally provided with the resin body cured at the molten resin material supply port when the resin frame member is molded. By fitting the resin body into the recess provided in the separator, the framed electrolyte membrane / electrode structure and the separator are positioned with respect to each other. For this reason, for example, it is not necessary to provide the MEA positioning ribs made of rubber by injection molding (LIM molding) in the separator.

  Accordingly, a dedicated positioning member is not necessary, and the cost can be reduced. Accordingly, the framed electrolyte membrane / electrode structure and the separator can be accurately and reliably positioned with a simple and economical configuration.

It is a disassembled perspective explanatory drawing of the electric power generation unit which comprises the fuel cell which concerns on embodiment of this invention. It is the II-II sectional view taken on the line of FIG. 1 of the said electric power generation unit. It is the III-III sectional view taken on the line of FIG. 1 of the said electric power generation unit. It is front explanatory drawing of the state with which the electrolyte membrane and electrode structure with a frame which comprises the said electric power generation unit, and the anode side separator were piled up. It is a perspective explanatory view of the positioning structure of the framed electrolyte membrane / electrode structure and the anode separator.

  As shown in FIG. 1, a fuel cell 10 according to an embodiment of the present invention is configured by stacking a plurality of power generation units 12 in an arrow A direction (horizontal direction) or an arrow C direction (gravity direction). The fuel cell 10 forms, for example, an in-vehicle fuel cell stack and is mounted on a fuel cell vehicle (not shown).

  As shown in FIGS. 1 to 3, the power generation unit 12 sandwiches the framed electrolyte membrane / electrode structure 14 between a cathode side separator 16 and an anode side separator 18. The cathode side separator 16 and the anode side separator 18 have a horizontally long (or vertically long) rectangular shape.

  The cathode-side separator 16 and the anode-side separator 18 are constituted by, 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. The metal plate has a rectangular shape on the plane and is formed into a concavo-convex shape by pressing into a wave shape. The cathode side separator 16 and the anode side separator 18 may be constituted by, for example, a carbon separator instead of the metal separator.

  As shown in FIG. 1, the power generation unit 12 includes an oxidant gas inlet communication hole 22 a and a fuel gas outlet communication hole 24 b at one end edge of the cathode side separator 16 and the anode side separator 18 in the long side direction (arrow B direction). Is provided. The oxidant gas inlet communication holes 22a communicate with each other in the direction of arrow A and supply an oxidant gas, for example, an oxygen-containing gas. The fuel gas outlet communication holes 24b communicate with each other in the direction of arrow A and discharge a fuel gas, for example, a hydrogen-containing gas.

  The power generation unit 12 is provided with a fuel gas inlet communication hole 24 a and an oxidant gas outlet communication hole 22 b at the other end edge in the long side direction (arrow B direction) of the cathode side separator 16 and the anode side separator 18. The fuel gas inlet communication holes 24a communicate with each other in the direction of arrow A to supply fuel gas. The oxidant gas outlet communication holes 22b communicate with each other in the direction of arrow A and discharge the oxidant gas.

  A pair of cooling media for supplying a cooling medium in close proximity to the oxidant gas inlet communication hole 22a at both ends in the short side direction (arrow C direction) of the power generation unit 12 and communicating with each other in the arrow A direction An inlet communication hole 26a is provided. A pair of cooling medium outlet communication holes 26b for discharging the cooling medium is provided near both ends of the short side direction (arrow C direction) of the power generation unit 12 near the fuel gas inlet communication hole 24a side.

  An oxidant gas flow path 28 communicating with the oxidant gas inlet communication hole 22a and the oxidant gas outlet communication hole 22b is formed on the surface 16a of the cathode side separator 16 facing the electrolyte membrane / electrode structure 14 with a frame. . The oxidant gas flow channel 28 has a plurality of linear flow channel grooves (may be wavy flow channel grooves) extending in the arrow B direction.

  An inlet buffer portion 30a and an outlet buffer portion 30b are provided in the vicinity of the inlet and the outlet of the oxidant gas channel 28 so as to be located outside the power generation region. Each of the inlet buffer portion 30a and the outlet buffer portion 30b has a plurality of embosses (or linear convex portions). A plurality of inlet connection grooves 32a are formed between the inlet buffer portion 30a and the oxidant gas inlet communication hole 22a. A plurality of outlet connection grooves 32b are formed between the outlet buffer portion 30b and the oxidizing gas outlet communication hole 22b.

  A part of the cooling medium flow path 34 that connects the pair of cooling medium inlet communication holes 26 a and the pair of cooling medium outlet communication holes 26 b is formed on the surface 16 b of the cathode separator 16. The cooling medium flow path 34 is formed by overlapping the back surface shape of the oxidant gas flow path 28 and the back surface shape of the fuel gas flow path 36 described later.

  A fuel gas flow path 36 that connects the fuel gas inlet communication hole 24a and the fuel gas outlet communication hole 24b is formed on the surface 18a of the anode separator 18 facing the framed electrolyte membrane / electrode structure 14. The fuel gas flow channel 36 has a plurality of linear flow channel grooves (may be wavy flow channel grooves) extending in the arrow B direction.

  An inlet buffer portion 38a and an outlet buffer portion 38b are provided in the vicinity of the inlet and the outlet of the fuel gas flow path 36, located outside the power generation region. The inlet buffer portion 38a and the outlet buffer portion 38b each have a plurality of embosses (or linear convex portions).

  A plurality of supply connection paths 40a are formed between the inlet buffer portion 38a and the fuel gas inlet communication hole 24a. A plurality of discharge connection paths 40b are formed between the outlet buffer portion 38b and the fuel gas outlet communication hole 24b. The plurality of supply connection paths 40a are covered with a lid member 42a, while the plurality of discharge connection paths 40b are covered with a lid member 42b.

  A first seal member 44 is integrally formed on the surfaces 16 a and 16 b of the cathode separator 16 so as to go around the outer peripheral edge of the cathode separator 16. A second seal member 46 is integrally formed on the surfaces 18 a and 18 b of the anode side separator 18 around the outer peripheral edge of the anode side separator 18.

  As the first seal member 44 and the second seal member 46, for example, EPDM, NBR, fluorine rubber, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene or acrylic rubber or the like, cushion material Alternatively, a sealing material having elasticity such as a packing material is used.

  As shown in FIGS. 1 to 3, the first seal member 44 has a flat seal portion (seal base) 44 f having a uniform thickness along the surface direction of the cathode-side separator 16. On the surface 16 b, a convex seal portion 44 a that seals the oxidant gas, the fuel gas, and the cooling medium in an airtight and liquid tight manner is integrally bulged and formed on the flat seal portion 44 f of the first seal member 44. The convex seal portion 44a abuts on the surface 18b of the adjacent anode-side separator 18.

  As shown in FIGS. 1 to 4, the second seal member 46 has a flat seal portion (seal base) 46 f having a uniform thickness along the surface direction of the anode-side separator 18. The flat seal portion 46f of the second seal member 46 is provided with an inner seal 46a that circulates around the fuel gas passage 36 and abuts a resin frame member (described later) 50 that constitutes the electrolyte membrane / electrode structure 14 with a frame. It is done.

  The flat seal portion 46f is provided with an outer seal 46b that goes around the outer periphery of the framed electrolyte membrane / electrode structure 14 and contacts the flat seal portion 44f of the adjacent cathode side separator 16. The flat seal portion 46f is provided with an outer peripheral seal (outer seal) 46c that goes around the outer periphery of the anode-side separator 18. The flat seal portion 46f is provided with a seal 46d on the surface 18b side. In the first seal member 44, an outer peripheral seal may be provided on the outer peripheral portion of the flat seal portion 44f as necessary.

  As shown in FIGS. 1 to 3, a framed electrolyte membrane / electrode structure 14 includes an electrolyte membrane / electrode structure 48 and a resin frame member formed around the outer periphery of the electrolyte membrane / electrode structure 48. 50.

  As shown in FIGS. 2 and 3, the electrolyte membrane / electrode structure 48 includes, for example, a solid polymer electrolyte membrane (cation exchange membrane) 52 in which a perfluorosulfonic acid thin film is impregnated with water. The solid polymer electrolyte membrane 52 is sandwiched between the cathode electrode 54 and the anode electrode 56.

  The cathode electrode 54 constitutes a so-called stepped MEA having a planar dimension smaller than that of the anode electrode 56 and the solid polymer electrolyte membrane 52. The cathode electrode 54, the anode electrode 56, and the solid polymer electrolyte membrane 52 may be set to the same plane size. Further, the anode electrode 56 may have a planar dimension smaller than the planar dimension of the cathode electrode 54 and the solid polymer electrolyte membrane 52.

  The cathode electrode 54 and the anode electrode 56 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 layer is formed on both surfaces of the solid polymer electrolyte membrane 52, for example.

  As shown in FIGS. 1 to 3, the electrolyte membrane / electrode structure 48 is located outside the terminal portion of the cathode electrode 54, and the resin frame member 50 is integrated with the outer peripheral edge of the solid polymer electrolyte membrane 52. Is done.

  The resin frame member 50 includes an oxidant gas inlet communication hole 22a, a fuel gas inlet communication hole 24a, a cooling medium inlet communication hole 26a, an oxidant gas outlet communication hole 22b, a fuel gas outlet communication hole 24b, and a cooling medium outlet communication hole 26b. It is set to the dimension placed inside. The outer shape of the resin frame member 50 is preferably set to correspond to the shapes of the oxidant gas flow channel 28 and the fuel gas flow channel 36, the buffer portion shape, and the like.

  As the resin material constituting the resin frame member 50, for example, engineering plastics, super engineering plastics, etc. are adopted in addition to general-purpose plastics having electrical insulation. In the mold for molding the resin frame member 50, a plurality of molten resin member supply ports are formed in order to fill the cavity (molding space) with the molten resin.

  A resin body 50a cured at the molten resin member supply port is integrally provided on the resin frame member 50 formed of resin. At least one resin body 50a is provided on each long side and each short side of the resin frame member 50 having a rectangular outer shape. The resin body 50a is preferably cut for each desired length after the resin frame member 50 is molded and released. Two resin bodies 50a can be provided on each long side of the resin frame member 50, and the number of the resin bodies 50a is set according to the cavity shape or the like.

  As shown in FIGS. 3 to 5, positioning concave portions 46 br and 46 cr into which the resin body 50 a is fitted are formed on the surface 18 a of the anode side separator 18. The recess 46br is formed by cutting out a part of the outer seal 46b of the second seal member 46, and the recess 46cr is formed by cutting out a part of the outer peripheral seal 46c of the second seal member 46. The recesses 46br and the recesses 46cr are arranged on a straight line corresponding to the resin body 50a, and are provided at least one on each side of the anode side separator 18.

  As shown in FIG. 3, a concave portion 44fr into which each resin body 50a is fitted is formed on the surface 16a of the cathode-side separator 16. The recess 44fr is formed by cutting out a part of the flat seal portion 44f of the first seal member 44. Note that when the thickness of the resin body 50a is smaller than the thickness of the resin frame member 50 and a gap is formed on the flat seal portion 44f side, the recess 44fr may not be provided.

  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 22a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 24a. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the pair of cooling medium inlet communication holes 26a.

  The oxidant gas is introduced into the oxidant gas flow path 28 of the cathode side separator 16 from the oxidant gas inlet communication hole 22a. The oxidant gas moves in the direction of arrow B (horizontal direction) along the oxidant gas flow path 28 and is supplied to the cathode electrode 54 of the electrolyte membrane / electrode structure 48.

  On the other hand, the fuel gas is introduced into the fuel gas passage 36 of the anode separator 18 from the fuel gas inlet communication hole 24a. The fuel gas moves in the horizontal direction (arrow B direction) along the fuel gas flow path 36 and is supplied to the anode electrode 56 of the electrolyte membrane / electrode structure 48.

  Therefore, in the electrolyte membrane / electrode structure 48, the oxidant gas supplied to the cathode electrode 54 and the fuel gas supplied to the anode electrode 56 are consumed by an electrochemical reaction in the electrode catalyst layer to generate power. Is called.

  Next, the oxidant gas supplied and consumed to the cathode electrode 54 of the electrolyte membrane / electrode structure 48 is discharged in the direction of arrow A along the oxidant gas outlet communication hole 22b. The fuel gas supplied to and consumed by the anode electrode 56 of the electrolyte membrane / electrode structure 48 is discharged in the direction of arrow A along the fuel gas outlet communication hole 24b.

  The cooling medium supplied to the pair of upper and lower cooling medium inlet communication holes 26 a is formed between the cathode separator 16 constituting one power generation unit 12 and the anode separator 18 constituting the other power generation unit 12. It is introduced into the cooling medium flow path 34.

  The cooling medium supplied to the cooling medium flow path 34 from each cooling medium inlet communication hole 26a once flows in the direction of the arrow C (gravity direction) and then moves in the direction of the arrow B (horizontal direction) to move the electrolyte. The membrane / electrode structure 48 is cooled. This cooling medium moves outward in the direction of arrow C, and is then discharged to the pair of cooling medium outlet communication holes 26b.

  In this case, in this embodiment, as shown in FIGS. 3 to 5, the resin frame member 50 constituting the electrolyte membrane / electrode structure 14 with a frame is formed of a molten resin material when the resin frame member 50 is molded. A resin body 50a cured at the supply port is integrally provided. On the other hand, the anode-side separator 18 is formed with recesses 46br and 46cr by cutting out part of the outer seal 46b and the outer peripheral seal 46c of the second seal member 46.

  The resin bodies 50a formed integrally with the resin frame member 50 are integrally fitted in the recesses 46br and 46cr of the anode-side separator 18. For this reason, the framed electrolyte membrane / electrode structure 14 and the anode separator 18 are positioned relative to each other. Therefore, for example, the anode-side separator 18 does not need to be provided with a rubber MEA positioning rib by injection molding (LIM molding).

  As a result, a dedicated positioning member is not required, and the cost can be reduced. Therefore, it is possible to obtain an effect that the framed electrolyte membrane / electrode structure 14 and the anode-side separator 18 can be accurately and reliably positioned with a simple and economical configuration.

  Further, the cathode-side separator 16 has a recess 44fr formed by cutting out a part of the flat seal portion 44f of the first seal member 44. Therefore, when the resin body 50a is fitted into the recess 44fr, the framed electrolyte membrane / electrode structure 14 and the cathode separator 16 can be accurately and reliably positioned. Thereby, the electric power generation unit 12 can be integrated rapidly, and there exists an advantage that the assembly operation of the fuel cell 10 is performed efficiently at once.

  In the present embodiment, the recesses 46br and 46cr into which the resin body 50a is fitted are formed by partially cutting the second seal member 46, but the present invention is not limited to this. For example, a concave portion may be formed on the metal plate itself constituting the anode side separator 18 and used as a positioning concave portion into which the resin body 50a is fitted.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell 12 ... Power generation unit 14 ... Electrode membrane / electrode structure with frame 16 ... Cathode side separator 18 ... Anode side separator 22a ... Oxidant gas inlet communication hole 22b ... Oxidant gas outlet communication hole 24a ... Fuel gas inlet communication Hole 24b ... Fuel gas outlet communication hole 26a ... Cooling medium inlet communication hole 26b ... Cooling medium outlet communication hole 28 ... Oxidant gas flow path 34 ... Cooling medium flow path 36 ... Fuel gas flow paths 44, 46 ... Seal member 44a ... Convex 44f, 46br, flat seal portions 44fr, 46br, 46cr ... concave portion 46a ... inner seal 46b ... outer seal 46c ... outer periphery seal 48 ... electrolyte membrane / electrode structure 50 ... resin frame member 50a ... resin body 52 ... solid high Molecular electrolyte membrane 54 ... Cathode electrode 56 ... Anode electrode

Claims (3)

An electrolyte membrane with a frame having an electrolyte membrane / electrode structure in which electrodes are arranged on both sides of the solid polymer electrolyte membrane, and a resin frame member is formed around the periphery of the electrolyte membrane / electrode structure. A fuel cell in which an electrode structure and a separator are stacked,
On the outer periphery of the resin frame member, a resin body that is integrally cured with the resin frame member at the molten resin material supply port at the time of molding is provided,
The separator is provided with a positioning recess into which the resin body is fitted.   2. The fuel cell according to claim 1, wherein the recess is provided by cutting out a seal member formed integrally with the separator. 3. The fuel cell according to claim 2, wherein the separator is provided with a fuel gas flow path for allowing fuel gas to flow along one separator surface.
The seal member circulates around the fuel gas flow path and contacts the resin frame member; and
An outer seal that goes around the outside of the resin frame member;
Have
The fuel cell, wherein the outer seal is formed with the recess into which the resin body is fitted.

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