JP2015103296A - Fuel cell stack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow for reliable reception of an external load being given to a fuel cell stack by a simple and compact configuration, and to especially allow for suppression of fuel gas leakage as much as possible.SOLUTION: A fuel cell 12 has a rectangular shape in the plan view, and at two corners diagonal to each other, a fuel gas supply communication hole 30a and a fuel gas exhaust communication hole 30b, for distributing fuel gas in the lamination direction, are provided. A fuel cell stack 10 includes a first fastening member 20a of L-shaped cross-section arranged at one corner to cover the region of the fuel gas supply communication hole 30a, and a second fastening member 20b of L-shaped cross-section arranged at the other corner to cover the region of the fuel gas discharge communication hole 30b.

Description

  The present invention includes a fuel cell in which an electrolyte membrane / electrode structure provided with a pair of electrodes on both sides of an electrolyte membrane and a separator are stacked, and ends at both ends in a stacking direction in which the plurality of fuel cells are stacked. The present invention relates to a fuel cell stack in which a plate is provided and a fastening member is disposed between the end plates.

  For example, a polymer electrolyte fuel cell is a power generation cell in which an electrolyte membrane / electrode structure (MEA) in which an anode electrode and a cathode electrode are arranged on both sides of an electrolyte membrane made of a polymer ion exchange membrane is sandwiched by separators. It has. This fuel cell is usually used as, for example, an in-vehicle fuel cell stack by stacking a predetermined number of power generation cells.

  In the fuel cell stack, particularly when used for in-vehicle use, it is necessary to stack a large number of power generation cells. For this reason, each power generation cell must be positioned and held accurately and firmly.

  Thus, for example, a fuel cell disclosed in Patent Document 1 is known. As shown in FIG. 5, this fuel cell includes a laminate 3 in which a plurality of separators 1 and electrode units 2 are laminated. Pressure plates (end plates) 4 a and 4 b are disposed at both ends in the stacking direction of the stacked body 3, and the pressure plates 4 a and 4 b are connected by four holding members 5. Each holding member 5 has an L-shaped cross section and is fixed to the four corners of the pressure plates 4a and 4b via bolts 6.

  Manifold piping 7a-7f which distribute | circulates fuel gas, oxidizing agent gas, and a cooling medium in a lamination direction is provided in the pressure plate 4a. For example, the manifold pipes 7a to 7c supply a fuel gas, an oxidant gas, and a cooling medium, while the manifold pipes 7d to 7f have a function of discharging the fuel gas, the oxidant gas, and the cooling medium.

JP 2000-48850 A

  However, in the fuel cell described above, the holding members 5 are bolted to the four corners of the pressure plates 4a and 4b, respectively. For this reason, there are problems that the assembly work of the fuel cell is considerably complicated and the number of parts is increased.

  Moreover, the holding member 5 is disposed so as to cover only a part of the manifold pipes 7a, 7c, 7d, and 7f. Therefore, when the fuel cell is used as an in-vehicle fuel cell stack, the holding member 5 cannot sufficiently protect the manifold pipes 7a to 7f from an external impact load (collision). As a result, the fuel gas communication hole cannot be particularly well protected from collision, and there is a problem that fuel gas leakage or the like is likely to occur.

  The present invention solves this type of problem and can reliably receive an external load applied to the fuel cell stack with a simple and compact configuration, and particularly suppresses leakage of fuel gas as much as possible. An object of the present invention is to provide a fuel cell stack that can be used.

  The fuel cell stack according to the present invention includes a fuel cell in which an electrolyte membrane / electrode structure provided with a pair of electrodes on both sides of an electrolyte membrane and a separator are stacked. End plates are provided at both ends in the stacking direction in which a plurality of fuel cells are stacked, and fastening members are disposed between the end plates.

  The fuel cell has a rectangular shape when viewed from the front, and is provided with a fuel gas supply communication hole and a fuel gas discharge communication hole through which fuel gas flows in the stacking direction at two corners that are diagonal to each other. . And a fastening member covers the area | region of a fuel gas discharge | release communicating hole in the other corner | angular part, and the 1st fastening member of the L-shaped cross section arrange | positioned covering the area | region of a fuel gas supply communicating hole in one corner | angular part. And a second fastening member having an L-shaped cross section to be disposed.

  Further, in this fuel cell stack, the first fastening member and the second fastening member have a length of the first side extending along the long side direction of the fuel cell and extending along the short side direction of the fuel cell. It is preferable that the length is longer than the length of the existing second side.

  Further, in this fuel cell stack, the separator includes two positioning members that extend in the stacking direction and contact the first fastening member, and at least one that extends in the stacking direction and contact the second fastening member. It is preferable that a positioning member is provided.

  According to the present invention, the first fastening member and the second fastening member are provided corresponding to the two corners of the fuel cell that are diagonal to each other. For this reason, compared with the normal fastening structure using four fastening members, while the number of the said fastening members is halved and a number of parts is reduced, assembly workability | operativity improves favorably.

  Moreover, the first fastening member is disposed so as to cover the region of the fuel gas supply communication hole, and the second fastening member is disposed so as to cover the region of the fuel gas discharge communication hole. Therefore, particularly when an external load is applied to the fuel cell stack, the fuel gas supply passage and the fuel gas discharge passage can be effectively protected.

  This makes it possible to reliably receive an external load applied to the fuel cell stack with a simple and compact configuration, and in particular, it is possible to suppress leakage of fuel gas as much as possible.

1 is a schematic perspective view of a fuel cell stack according to an embodiment of the present invention. It is front explanatory drawing from the 1st end plate side of the said fuel cell stack. It is a disassembled perspective explanatory drawing of the 1st fastening member and the 2nd fastening member which comprise the said fuel cell stack. It is a principal part disassembled perspective explanatory drawing of the fuel cell which comprises the said fuel cell stack. 2 is a perspective explanatory view of a fuel cell disclosed in Patent Document 1. FIG.

  As shown in FIG. 1, the fuel cell stack 10 according to the embodiment of the present invention is mounted on, for example, a fuel cell electric vehicle (not shown). In the fuel cell stack 10, a plurality of fuel cells 12 are stacked in the arrow A direction in a standing posture (the electrode surface is parallel to the vertical direction). The fuel cell 12 may be stacked in the direction of arrow C in a horizontal posture.

  A first end plate 18a is disposed on one end side in the stacking direction of the fuel cell 12 via a first terminal plate 14a and a first insulating plate 16a. At the other end of the fuel cell 12 in the stacking direction, a second end plate 18b is disposed via a second terminal plate 14b and a second insulating plate 16b. A first output terminal 19a connected to the first terminal plate 14a extends from the center of the first end plate 18a. A second output terminal 19b connected to the second terminal plate 14b extends from the center of the second end plate 18b.

  As shown in FIGS. 1 to 3, the first end plate 18 a and the second end plate 18 b have a horizontally long rectangular shape in front view. As will be described later, a first fastening member 20a and a second fastening member 20b are disposed at two corners of the first end plate 18a and the second end plate 18b that are opposite to each other.

  As shown in FIG. 4, the fuel cell 12 includes an electrolyte membrane / electrode structure 22, and a cathode side separator 24 and an anode side separator 26 that sandwich the electrolyte membrane / electrode structure 22. The cathode side separator 24 and the anode side separator 26 are made of, for example, a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, or a thin plate-like metal separator whose surface is subjected to anticorrosion treatment.

  The metal separator has a rectangular planar shape, and is formed into a concavo-convex shape by pressing into a wave shape. The cathode side separator 24 and the anode side separator 26 may be constituted by, for example, a carbon separator instead of the metal separator.

  The cathode-side separator 24 and the anode-side separator 26 have a horizontally long shape, so that the short sides are directed in the direction of gravity (arrow C direction) and the long sides are directed in the horizontal direction (arrow B direction) (horizontal stacking). Composed. A configuration in which the short side is directed in the horizontal direction and the long side is directed in the direction of gravity may be employed.

  An oxidant gas supply communication hole 28a and a fuel gas discharge communication hole 30b are provided at one end edge in the long side direction (arrow B direction) of the fuel cell 12 so as to communicate with each other in the arrow A direction. The oxidant gas supply communication hole 28a supplies an oxidant gas, for example, an oxygen-containing gas, while the fuel gas discharge communication hole 30b discharges a fuel gas, for example, a hydrogen-containing gas.

  The other end edge of the long side direction of the fuel cell 12 communicates with each other in the direction of arrow A, and a fuel gas supply communication hole 30a for supplying fuel gas, and an oxidant gas for discharging oxidant gas A discharge communication hole 28b is provided.

  Two cooling medium supply communication holes 32a are provided on one side of both ends in the short side direction (arrow C direction) of the fuel cell 12 so as to communicate with each other in the arrow A direction and supply a cooling medium. It is done. Two cooling medium discharge communication holes 32 b for discharging the cooling medium are provided vertically on the other side of both end portions in the short side direction of the fuel cell 12.

  The electrolyte membrane / electrode structure 22 includes, for example, a fluorine-based or hydrocarbon-based solid polymer electrolyte membrane (cation exchange membrane) 34, and a cathode electrode 36 and an anode electrode 38 that sandwich the solid polymer electrolyte membrane 34. Is provided.

  The cathode electrode 36 and the anode electrode 38 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. An electrode catalyst layer (not shown). The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 34.

  An oxidant gas flow path 40 that connects the oxidant gas supply communication hole 28a and the oxidant gas discharge communication hole 28b is formed on the surface 24a of the cathode separator 24 facing the electrolyte membrane / electrode structure 22. The oxidant gas channel 40 is formed by a plurality of linear or wavy channel grooves extending in the arrow B direction.

  In the vicinity of the inlet and outlet of the oxidant gas flow path 40, an inlet buffer portion 42a and an outlet buffer portion 42b each having a plurality of protruding embosses (or line-shaped protruding portions) are provided. The inlet buffer portion 42a and the oxidant gas supply communication hole 28a communicate with each other through a plurality of inlet connection channels 43a. The outlet buffer portion 42b and the oxidant gas discharge communication hole 28b communicate with each other through a plurality of outlet connection channels 43b.

  A fuel gas flow path 44 that connects the fuel gas supply communication hole 30a and the fuel gas discharge communication hole 30b is formed on the surface 26a of the anode separator 26 facing the electrolyte membrane / electrode structure 22. The fuel gas channel 44 is formed by a plurality of linear or wavy channel grooves extending in the arrow B direction.

  In the vicinity of the inlet and outlet of the fuel gas channel 44, an inlet buffer portion 46a and an outlet buffer portion 46b each having a plurality of protruding embosses (or line-shaped protruding portions) are provided. The inlet buffer portion 46a and the fuel gas supply communication hole 30a communicate with each other through a plurality of inlet connection channels 48a. The outlet buffer portion 46b and the fuel gas discharge communication hole 30b communicate with each other through a plurality of outlet connection channels 48b.

  Between the surface 26b of the anode side separator 26 and the surface 24b of the cathode side separator 24, a cooling medium flow path 50 communicating with the cooling medium supply communication holes 32a and 32a and the cooling medium discharge communication holes 32b and 32b is formed. The The cooling medium flow path 50 circulates the cooling medium over the electrode range of the electrolyte membrane / electrode structure 22. A plurality of inlet connection channels 52a are provided in the vicinity of the cooling medium supply communication hole 32a, and a plurality of outlet connection channels 52b are provided in the vicinity of the cooling medium discharge communication hole 32b.

  A first seal member 54 is integrally formed on the surfaces 24 a and 24 b of the cathode separator 24 around the outer peripheral edge of the cathode separator 24. A second seal member 56 is integrally formed on the surfaces 26 a and 26 b of the anode separator 26 so as to go around the outer peripheral edge of the anode separator 26.

  As the first seal member 54 and the second seal member 56, 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, an elastic seal member such as a packing material is used.

  In the present embodiment, a guide recess 58a is formed on the upper side (upper long side) of the fuel cell 12 between the fuel gas supply communication hole 30a and the cooling medium discharge communication hole 32b. A guide recess 58b is formed on the lower side (longer side on the lower side) of the fuel cell 12 between the fuel gas discharge communication hole 30b and the cooling medium supply communication hole 32a. The guide recesses 58a and 58b are not limited to the shape, and may have a curved shape portion on the tip side, for example.

  A guide recess 60a is formed on one side (one short side) of the fuel cell 12 between the fuel gas discharge communication hole 30b and the oxidant gas supply communication hole 28a. A guide recess 60b is formed on the other side (the other short side) of the fuel cell 12 between the fuel gas supply communication hole 30a and the oxidant gas discharge communication hole 28b. The guide recesses 60a and 60b are not limited to the shape, and may include, for example, a rectangular shape portion.

  As shown in FIGS. 2 and 3, the fuel cell stack 10 includes guide members 62 a that extend along the stacking direction of the fuel cells 12 and are integrally disposed in the respective guide recesses 58 a. The fuel cell stack 10 includes guide members 62b that extend along the stacking direction of the fuel cells 12 and are integrally disposed in the respective guide recesses 58b. The guide members 62a and 62b are made of an electrically insulating material such as a polymer material.

  The guide members 62a and 62b preferably have a curved cross section corresponding to the opening shape of the guide recesses 58a and 58b. The surfaces 62as and 62bs of the guide members 62a and 62b protrude outward from the upper and lower surfaces of the fuel cell 12 (see FIG. 2).

  As shown in FIGS. 2 and 3, the fuel cell stack 10 includes guide members 64 a that extend along the stacking direction of the fuel cells 12 and are integrally disposed in the respective guide recesses 60 a. The fuel cell stack 10 has a guide member 64b that extends along the stacking direction of the fuel cells 12 and is integrally disposed in each guide recess 60b. The guide members 64a and 64b are made of an electrically insulating material, for example, a polymer material. The guide members 64a and 64b preferably have a rectangular shape corresponding to the opening shape of the guide recesses 60a and 60b.

  The surfaces 64as and 64bs of the guide members 64a and 64b protrude outward from the side surface of the fuel cell 12 (see FIG. 2). The guide recess 60b and the guide member 64b may be used as necessary and can be omitted.

  The first fastening member 20a has a cross-sectional bent shape, for example, an L-shaped cross section, and is disposed so as to cover the region of the fuel gas supply communication hole 30a. Specifically, the first fastening member 20a includes a first side portion 66a extending along the upper side (long side) direction of the fuel cell 12 and a side side (short side) direction of the fuel cell 12. The extending second side portion 68a is integrally provided orthogonal to each other. The first side portion 66a is disposed so as to cover the upper side of the coolant discharge passage 32b from the upper side of the fuel gas supply passage 30a. The first side portion 66a only needs to cover at least the fuel gas supply communication hole 30a. The second side portion 68a is disposed so as to cover the side of the fuel gas supply communication hole 30a.

  The inner surface of the first side portion 66a contacts the surface 62as of the guide member 62a, and the inner surface of the second side portion 68a contacts the surface 64bs of the guide member 64b. One or more, for example, two screw holes 70 are formed at both ends of the first side portion 66a. Bolts 72 are screwed into the respective screw holes 70, whereby both ends of the first side portion 66a are fixed to the first end plate 18a and the second end plate 18b. One or more, for example, two screw holes 70 are formed at both ends of the second side portion 68a, and the second side portion 68a is connected to the first end plate 18a and the second end plate 18b via bolts 72. Fixed.

  The second fastening member 20b has a bent cross-sectional shape, for example, an L-shaped cross section, and is disposed so as to cover the region of the fuel gas discharge communication hole 30b. Specifically, the second fastening member 20b includes a first side portion 66b extending along the lower side (long side) direction of the fuel cell 12, and a side side (short side) direction of the fuel cell 12. The extending second side portion 68b is integrally provided orthogonal to each other. The first side portion 66b is disposed so as to cover the lower side of the cooling medium supply communication hole 32a from the lower side of the fuel gas discharge communication hole 30b. The first side 66b only needs to cover at least the fuel gas discharge communication hole 30b. The second side portion 68b is disposed so as to cover the side of the fuel gas discharge communication hole 30b.

  The inner surface of the first side portion 66b contacts the surface 62bs of the guide member 62b, and the inner surface of the second side portion 68b contacts the surface 64as of the guide member 64a. One or more, for example, two screw holes 70 are formed at both ends of the first side portion 66b. Bolts 72 are screwed into the respective screw holes 70, whereby both ends of the first side portion 66b are fixed to the first end plate 18a and the second end plate 18b. One or more, for example, two screw holes 70 are formed at both ends of the second side portion 68b, and the second side portion 68b is connected to the first end plate 18a and the second end plate 18b via bolts 72. Fixed.

  As shown in FIG. 1, all the communication holes are formed in the first end plate 18a. All the communication holes are an oxidant gas supply communication hole 28a, an oxidant gas discharge communication hole 28b, a fuel gas supply communication hole 30a, a fuel gas discharge communication hole 30b, a cooling medium supply communication hole 32a, and a cooling medium discharge communication hole 32b. is there. A manifold member (not shown) is connected to each communication hole.

  Note that only the oxidant gas supply communication hole 28a, the fuel gas supply communication hole 30a, the oxidant gas discharge communication hole 28b, and the fuel gas discharge communication hole 30b may be formed in the first end plate 18a. At that time, a cooling medium supply communication hole 32a and a cooling medium discharge communication hole 32b are formed in the second end plate 18b.

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

  First, as shown in FIG. 1, oxidant gas such as oxygen-containing gas is supplied to the oxidant gas supply communication hole 28a of the first end plate 18a, and hydrogen is contained in the fuel gas supply communication hole 30a. Fuel gas such as gas is supplied. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the pair of cooling medium supply communication holes 32a.

  Therefore, as shown in FIG. 4, the oxidant gas is introduced into the oxidant gas flow path 40 of the cathode side separator 24 from the oxidant gas supply communication hole 28 a. The oxidant gas moves in the direction of arrow B along the oxidant gas flow path 40 and is supplied to the cathode electrode 36 of the electrolyte membrane / electrode structure 22.

  On the other hand, the fuel gas is supplied to the fuel gas passage 44 of the anode separator 26 from the fuel gas supply communication hole 30a. The fuel gas moves in the direction of arrow B along the fuel gas flow path 44 and is supplied to the anode electrode 38 of the electrolyte membrane / electrode structure 22.

  Therefore, in the electrolyte membrane / electrode structure 22, the oxidant gas supplied to the cathode electrode 36 and the fuel gas supplied to the anode electrode 38 are consumed by an electrochemical reaction in the electrode catalyst layer to generate power. Is called.

  Next, the oxidant gas consumed by being supplied to the cathode electrode 36 of the electrolyte membrane / electrode structure 22 is discharged in the direction of arrow A along the oxidant gas discharge communication hole 28b. On the other hand, the fuel gas supplied to and consumed by the anode electrode 38 of the electrolyte membrane / electrode structure 22 is discharged in the direction of arrow A along the fuel gas discharge communication hole 30b.

  The cooling medium supplied to the pair of cooling medium supply communication holes 32 a is introduced into the cooling medium flow path 50 between the cathode side separator 24 and the anode side separator 26. The cooling medium once flows in the direction indicated by the arrow C and then moves in the direction indicated by the arrow B to cool the electrolyte membrane / electrode structure 22. The cooling medium moves outward in the direction of arrow C, and is then discharged in the direction of arrow A along the pair of cooling medium discharge communication holes 32b.

  In this case, in this embodiment, as shown in FIGS. 1 to 3, the fuel gas supply communication hole 30 a and the fuel gas discharge communication hole 30 b correspond to the two corners of the fuel cell 12 that are diagonal to each other. Is formed. The first end plate 18a and the second end plate 18b constituting the fuel cell stack 10 correspond to the corners where the fuel gas supply communication holes 30a and the fuel gas discharge communication holes 30b are formed. A first fastening member 20a and a second fastening member 20b are provided.

  For this reason, the number of the fastening members is halved compared to a normal fastening structure using four fastening members, and specifically, the number is halved to two of the first fastening member 20a and the second fastening member 20b. . Therefore, in the fuel cell stack 10, the number of parts is greatly reduced and the assembly workability is improved satisfactorily.

  Moreover, the first fastening member 20a is disposed so as to cover the region of the fuel gas supply communication hole 30a by the first side portion 66a and the second side portion 68a which are orthogonal to each other. The second fastening member 20b is disposed so as to cover the region of the fuel gas discharge communication hole 30b by a first side portion 66b and a second side portion 68b that are orthogonal to each other. Thereby, especially when an external load is applied to the fuel cell stack 10, the fuel gas supply communication hole 30a and the fuel gas discharge communication hole 30b can be effectively protected.

  For this reason, it is possible to reliably receive an external load applied to the fuel cell stack 10 with a simple and compact configuration, and in particular, it is possible to obtain an effect that the leakage of the fuel gas can be suppressed as much as possible. .

  Further, in the present embodiment, guide members 62a and 62b are disposed in the guide recesses 58a and 58b formed in each fuel cell 12, and the surfaces 62as and 62bs of the guide members 62a and 62b are the first sides. It is in contact with the inner surfaces of the portions 66a and 66b. On the other hand, guide members 64a and 64b are disposed in the guide recesses 60a and 60b formed in each fuel cell 12, and the surfaces 64as and 64bs of the guide members 64a and 64b are formed on the second side portions 68a and 68b. It is in contact with the inner surface. Therefore, each fuel cell 12 has an advantage that it is accurately positioned and held firmly and securely.

  Furthermore, the first fastening member 20a has a long first side portion 66a disposed so as to cover the fuel gas supply communication hole 30a and the cooling medium discharge communication hole 32b. The 2nd fastening member 20b has the 1st edge part 66b arrange | positioned so that the downward direction of the cooling-medium supply communication hole 32a may be covered from the downward direction of the fuel gas discharge | release communication hole 30b. Thereby, the 1st fastening member 20a and the 2nd fastening member 20b can have sufficient rigidity, and it becomes possible to hold | maintain the some laminated | stacked fuel cell 12 firmly and reliably.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell stack 12 ... Fuel cell 18a, 18b ... End plate 20a, 20b ... Fastening member 22 ... Electrolyte membrane electrode assembly 24, 26 ... Separator 28a ... Oxidant gas supply communication hole 28b ... Oxidant gas discharge communication hole 30a ... Fuel gas supply communication hole 30b ... Fuel gas discharge communication hole 32a ... Cooling medium supply communication hole 32b ... Cooling medium discharge communication hole 34 ... Solid polymer electrolyte membrane 36 ... Cathode electrode 38 ... Anode electrode 40 ... Oxidant gas flow path 44 ... Fuel gas passage 50 ... Cooling medium passage 54, 56 ... Seal members 58a, 58b, 60a, 60b ... Guide recesses 62a, 62b, 64a, 64b ... Guide members 66a, 66b, 68a, 68b ... Sides

Claims (3)

A fuel cell in which an electrolyte membrane / electrode structure provided with a pair of electrodes on both sides of the electrolyte membrane and a separator are stacked is provided, and end plates are provided at both ends in the stacking direction in which the plurality of fuel cells are stacked. And a fuel cell stack in which a fastening member is disposed between the end plates,
The fuel cell has a rectangular shape when viewed from the front, and is provided with a fuel gas supply communication hole and a fuel gas discharge communication hole through which fuel gas flows in the stacking direction at two corners that are diagonal to each other. With
The fastening member is a first fastening member having an L-shaped cross section disposed at one corner to cover the region of the fuel gas supply communication hole,
A second fastening member having an L-shaped cross section disposed to cover the region of the fuel gas discharge communication hole at the other corner,
A fuel cell stack comprising:   2. The fuel cell stack according to claim 1, wherein the first fastening member and the second fastening member have a length of a first side extending along a long side direction of the fuel cell, and a short side of the fuel cell. A fuel cell stack characterized by being configured to be longer than the length of the second side extending along the direction. The fuel cell stack according to claim 1 or 2, wherein the separator includes two positioning members extending in the stacking direction and contacting the first fastening member.
At least one positioning member extending in the stacking direction and contacting the second fastening member;
A fuel cell stack.

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