JP2013161550A - Fuel cell stack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To successfully perform positioning of a fuel cell with a simple and compact constitution.SOLUTION: In a fuel cell stack 10, a plurality of fuel cells 12 are stacked. In each of the fuel cells 12, an electrolyte membrane-electrode structure 30 is held with an anode side separator 32 and a cathode side separator 34. In each of the fuel cells 12, circular projecting parts 58a and 58b projecting in a separator face direction intersecting the lamination direction are provided, and the projecting parts 58a and 58b are accommodated in circular recessed parts 62a and 62b formed in fastening members 24a and 24c.

Description

  The present invention includes a fuel cell in which an electrolyte / electrode structure provided with a pair of electrodes on both sides of an electrolyte and a separator are stacked. The fuel cells are stacked, and end plates are arranged at both ends in the stacking direction. The present invention relates to a fuel cell stack that is provided and is configured such that the end plates are fastened by a plurality of fastening members.

  For example, a solid polymer fuel cell employs a solid polymer electrolyte membrane made of a polymer ion exchange membrane. This fuel cell has an electrolyte membrane / electrode structure (MEA) constituted by arranging an anode electrode and a cathode electrode made of an electrode catalyst and porous carbon (gas diffusion layer) on both sides of a solid polymer electrolyte membrane. The power generation cell is sandwiched between separators (bipolar plates). A fuel cell in which a plurality of power generation cells are stacked is used as, for example, an in-vehicle fuel cell stack.

  In a fuel cell stack, an internal manifold is often configured to supply a fuel gas and an oxidant gas, which are reaction gases, to the anode electrode and the cathode electrode of each stacked power generation cell. The internal manifold includes a reaction gas supply communication hole and a reaction gas discharge communication hole that are provided through the power generation cell in the stacking direction.

  In this type of fuel cell stack, it is necessary to stack a large number of power generation cells, particularly when used for in-vehicle use. For this reason, each electric power generation cell must be positioned correctly, for example, the assembly method of the fuel cell currently disclosed by patent document 1 is known.

  As shown in FIG. 8, in this assembling method, a cell assembly positioning hole 3 is formed in a pressurizing plate 2 for pressurizing the stack 1, and the positioning hole 3 is made of a long PTFE having a chamfered end surface. The knock pin 4 is inserted in an upright state. Next, the cells 5 in which the positioning holes 3 are formed are stacked in such a manner that the positioning holes 3 are sequentially fitted to the knock pins 4 and stacked. Thereafter, the stack 1 is fastened and fixed.

JP-A-9-134734

  In the above-mentioned Patent Document 1, the positioning hole 3 is formed in the cell 5 constituting the stack 1, and the knock pin 4 is disposed through the cell 5. For this reason, in the plane of the cell 5, there is a problem that the layout of each communication hole is restricted and the cell 5 itself is considerably enlarged.

  An object of the present invention is to solve this type of problem, and to provide a fuel cell stack capable of satisfactorily positioning a fuel cell with a simple and compact configuration.

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

  In this fuel cell stack, the fuel cell is provided with one or more projecting portions projecting in a direction intersecting the stacking direction, and at least one fastening member is formed with a concave portion that accommodates the projecting portion. Has been.

  Further, in this fuel cell stack, the fuel cell is provided with a fuel gas communication hole through which the fuel gas flows at least along the stacking direction and an oxidant gas communication hole through which the oxidant gas flows, and the projecting portion It is preferable to arrange in the vicinity of the fuel gas communication hole.

  In the present invention, the fuel cell is provided with a protruding portion that protrudes in a direction crossing the stacking direction, and the protruding portion is accommodated in a concave portion formed in the fastening member. For this reason, each fuel cell is easily and reliably positioned under the fitting action of the protruding portion and the concave portion.

  At that time, the fastening member can share both the fastening function and the positioning function, and the configuration can be easily simplified. In addition, the projecting portion is formed so as to project outward from the fuel cell, so that the layout of the flow path and the communication hole inside the fuel cell is not affected.

1 is a schematic perspective explanatory view of a fuel cell stack according to a first embodiment of the present invention. It is a partial cross section side view of 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. It is front explanatory drawing of the anode side separator which comprises the said fuel cell stack. It is explanatory drawing of the assembly | attachment operation | work of the said fuel cell stack. It is principal part explanatory drawing of the fuel cell stack which concerns on the 2nd Embodiment of this invention. It is a principal part disassembled perspective explanatory drawing of the fuel cell which comprises the fuel cell stack which concerns on the 3rd Embodiment of this invention. 10 is an explanatory diagram of a method for assembling a fuel cell disclosed in Patent Document 1. FIG.

  As shown in FIG. 1, the fuel cell stack 10 according to the first embodiment of the present invention includes a stacked body 14 in which a plurality of fuel cells 12 are stacked in a horizontal direction (arrow B direction) in a standing posture. . The fuel cell 12 may be stacked in the vertical direction (arrow C direction) in a horizontal posture.

  A first end plate 20a and a second end plate 20b are disposed at both ends in the stacking direction of the stacked body 14 via terminal plates 16a and 16b and insulating plates 18a and 18b. An output terminal 22a connected to the terminal plate 16a extends from the center of the first end plate 20a, while an output terminal 22b connected to the terminal plate 16b extends from the center of the second end plate 20b. Exists.

  The first end plate 20a and the second end plate 20b have a horizontally long (or vertically long) rectangular shape, and fastening members 24a, 24b, 24c and 24d having a substantially L-shaped cross section are provided between the corners. Be placed. Each fastening member 24a to 24d is fixed at both ends to the first end plate 20a and the second end plate 20b via bolts 26, and applies a tightening load in the stacking direction (arrow B direction) to the plurality of stacked fuel cells 12. Give.

  As shown in FIGS. 2 and 3, the fuel cell 12 has a horizontally long (or vertically long) rectangular shape, and an electrolyte membrane / electrode structure 30 is sandwiched between an anode side separator 32 and a cathode side separator 34. The anode-side separator 32 and the cathode-side separator 34 are made of, for example, a metal separator such as a steel plate, a stainless steel plate, an aluminum plate, or a plated steel plate, or a carbon separator.

  One end edge of the fuel cell 12 in the direction of arrow A (the horizontal direction in FIG. 3) communicates with each other in the direction of arrow B, which is the stacking direction, and oxidant for supplying an oxidant gas, for example, an oxygen-containing gas Agent gas supply communication hole (oxidant gas communication hole) 36a, cooling medium supply communication hole 38a for supplying a cooling medium, and fuel gas discharge communication hole (fuel gas) for discharging a fuel gas, for example, a hydrogen-containing gas (Communication holes) 40b are arranged in the direction of arrow C (vertical direction).

  The other end edge of the fuel cell 12 in the direction of arrow A communicates with each other in the direction of arrow B, a fuel gas supply communication hole (fuel gas communication hole) 40a for supplying fuel gas, and for discharging the cooling medium. The cooling medium discharge communication holes 38b and the oxidant gas discharge communication holes (oxidant gas communication holes) 36b for discharging the oxidant gas are arranged in the direction of arrow C.

  As shown in FIG. 4, a fuel gas flow path 42 communicating with the fuel gas supply communication hole 40 a and the fuel gas discharge communication hole 40 b is provided on the surface 32 a of the anode side separator 32 facing the electrolyte membrane / electrode structure 30. It is done. The fuel gas channel 42 is constituted by, for example, a plurality of grooves extending in the arrow A direction.

  As shown in FIG. 3, a cooling medium flow path 44 that connects the cooling medium supply communication hole 38 a and the cooling medium discharge communication hole 38 b is formed on the surface 32 b of the anode side separator 32. The cooling medium flow path 44 is constituted by a plurality of grooves extending in the arrow A direction.

  An oxidant gas flow path 46 that communicates with the oxidant gas supply communication hole 36a and the oxidant gas discharge communication hole 36b is provided on the surface 34a of the cathode separator 34 facing the electrolyte membrane / electrode structure 30. The oxidant gas channel 46 is constituted by, for example, a plurality of grooves extending in the direction of arrow A.

  A cooling medium that connects the cooling medium supply communication hole 38a and the cooling medium discharge communication hole 38b between the surface 32b of the anode side separator 32 and the surface 34b of the cathode side separator 34 constituting the fuel cells 12 adjacent to each other. A flow path 44 is provided.

  Seal members 48 and 50 are integrally or individually provided on the anode side separator 32 and the cathode side separator 34, respectively. The seal members 48 and 50 use, for example, a seal material such as EPDM, NBR, fluoro rubber, silicon rubber, fluorosilicon rubber, butyl rubber, natural rubber, styrene rubber, chloroplane, or acrylic rubber, a cushion material, or a packing material. To do.

  2 and 3, the electrolyte membrane / electrode structure 30 includes, for example, a solid polymer electrolyte membrane 52 in which a perfluorosulfonic acid thin film is impregnated with water, and the solid polymer electrolyte membrane 52 sandwiched between them. The cathode electrode 54 and the anode electrode 56 are provided.

  The cathode electrode 54 and the anode electrode 56 are an electrode catalyst formed by uniformly applying a gas diffusion layer 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 having a layer. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 52.

  Specifically, one diagonal position of the fuel cell 12 has a positioning protrusion 58a, a corner near the fuel gas supply passage 40a and a corner near the fuel gas discharge passage 40b, respectively. 58b is provided. The protrusions 58a and 58b are provided on the anode side separator 32 and the cathode side separator 34 so as to protrude outward in the surface direction (direction intersecting the stacking direction), respectively. It should be noted that only the protrusion 58a or only the protrusion 58b may be provided.

  As shown in FIGS. 3 and 4, in the anode separator 32, for example, a resin base 60 a is integrally formed at a corner near the fuel gas supply communication hole 40 a, and the base 60a is integrally provided with a circular protrusion 58a in front view. For example, a resin base portion 60b is integrally formed at a corner portion close to the fuel gas discharge communication hole 40b, and a circular protrusion 58b is integrally formed with the base portion 60b in a front view. Provided.

  As shown in FIG. 3, in the cathode-side separator 34, like the anode-side separator 32, a resin base portion is provided in the vicinity of the fuel gas supply communication hole 40a and in the vicinity of the fuel gas discharge communication hole 40b, respectively. Circular protrusions 58a and 58b are integrally provided in a front view through 60a and 60b. The protrusions 58a and 58b may be provided only on the anode side separator 32 or only on the cathode side separator 34.

  As shown in FIG. 1, the fastening member 24a is at the corner near the fuel gas supply communication hole 40a, the fastening member 24b is at the corner near the oxidant gas supply communication hole 36a, and the fastening member 24c is at the fuel. The fastening members 24d are disposed at the corners close to the gas discharge communication hole 40b and at the corners close to the oxidant gas discharge communication hole 36b, respectively.

  As shown in FIGS. 3 and 4, a circular concave portion 62a for fitting the protruding portion 58a is formed at the inner corner of the fastening member 24a. A circular concave portion 62b for fitting the protruding portion 58b is formed at the inner corner of the fastening member 24c.

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

  First, as shown in FIG. 5, for example, at least corner portions of the second end plate 20b adjacent to the fuel gas supply communication hole 40a and the fuel gas discharge communication hole 40b are connected to the fastening members 24a and 24c. One end is fixed via a bolt 26. In addition, you may fix the one end part of all the fastening members 24a-24d to the 2nd end plate 20b. On the other hand, in the fuel cell 12, the electrolyte membrane / electrode structure 30 is held while being sandwiched between the anode-side separator 32 and the cathode-side separator 34.

  Next, each fuel cell 12 fits each protrusion 58a to the concave portion 62a of the fastening member 24a, and fits each protrusion 58b to the concave portion 62b of the fastening member 24c to be on the second end plate 20b. Laminated. In addition, although not shown in figure, the insulating plate 18b and the terminal plate 16b are laminated | stacked previously on the 2nd end plate 20b.

  After a predetermined number of fuel cells 12 are stacked on the second end plate 20b under the guiding action of the protrusions 58a and 58b and the concave portions 62a and 62b, the terminal plate 16a and the insulation are formed on the fuel cell 12. Plates 18a are stacked. Further, a first end plate 20a is disposed on the insulating plate 18a.

  The other end portions of the fastening members 24a and 24b are fixed to the first end plate 20a by bolts 26, and both end portions of the fastening members 24b and 24d are connected to the first end plate 20a and the first end plate 20a via the bolts 26. It is fixed to the second end plate 20b. Thereby, the fuel cell stack 10 is assembled.

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

  As shown in FIG. 3, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas supply communication hole 36a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas supply communication hole 40a. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the cooling medium supply communication hole 38a.

  Therefore, the oxidant gas is introduced into the oxidant gas flow path 46 of the cathode-side separator 34 from the oxidant gas supply communication hole 36a. The oxidant gas is supplied to the cathode electrode 54 constituting the electrolyte membrane / electrode structure 30 while flowing in the direction of arrow A along the oxidant gas flow path 46.

  On the other hand, the fuel gas is introduced into the fuel gas passage 42 of the anode separator 32 from the fuel gas supply communication hole 40a. The fuel gas is supplied to the anode electrode 56 constituting the electrolyte membrane / electrode structure 30 while flowing in the arrow A direction along the fuel gas flow path 42.

  Therefore, in the electrolyte membrane / electrode structure 30, 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.

  Subsequently, the oxidant gas consumed by being supplied to the cathode electrode 54 is discharged in the direction of arrow B along the oxidant gas discharge communication hole 36b. On the other hand, the fuel gas supplied to and consumed by the anode electrode 56 is discharged in the direction of arrow B along the fuel gas discharge communication hole 40b.

  Further, the cooling medium supplied to the cooling medium supply communication hole 38 a is introduced into the cooling medium flow path 44 between the anode side separator 32 and the cathode side separator 34 and then circulates in the direction of arrow A. The cooling medium is discharged from the cooling medium discharge communication hole 38b after the electrolyte membrane / electrode structure 30 is cooled.

  In this case, in the first embodiment, the fuel cell 12 (specifically, the anode-side separator 32 and the cathode-side separator 34) has a circular protrusion 58a that protrudes in the separator surface direction intersecting the stacking direction, 58b is provided. And the protrusion parts 58a and 58b are accommodated in the circular recessed parts 62a and 62b formed in the fastening members 24a and 24c. For this reason, the effect that each fuel cell 12 is easily and reliably positioned under the fitting action of the projecting portions 58a and 58b and the recessed portions 62a and 62b is obtained.

  At that time, the fastening members 24a and 24c can share both the fastening function and the positioning function, and the configuration can be easily simplified. In addition, the protrusions 58a and 58b are formed so as to protrude outward in the separator surface direction of the fuel cell 12, and do not affect the layout of the flow paths and communication holes inside the fuel cell 12.

  Furthermore, the protrusions 58a and 58b are provided at a corner near the fuel gas supply communication hole 40a and a corner near the fuel gas discharge communication hole 40b. Accordingly, the positioning of the fuel gas supply communication hole 40a and the fuel gas discharge communication hole 40b can be easily and reliably performed, and the displacement can be suppressed as much as possible. As a result, the fuel gas supply communication hole 40a and the fuel gas discharge communication hole 40b can be positioned and held with high accuracy and the seal width can be set narrow.

  FIG. 6 is an explanatory view of a main part of a fuel cell stack 80 according to the second embodiment of the present invention. The same components as those of the fuel cell stack 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Similarly, in the third embodiment described below, detailed description thereof is omitted.

  The fuel cell stack 80 stacks a plurality of fuel cells 82 and applies a tightening force in the stacking direction to the fuel cells 82 by fastening members 84a to 84d. The fastening member 84a is near the corner near the fuel gas supply passage 40a, the fastening member 84b is near the corner near the oxidant gas supply passage 36a, and the fastening member 84c is near the fuel gas discharge passage 40b. The fastening members 84d are respectively disposed at the corners close to the oxidizing gas discharge communication hole 36b.

  In the fuel cell 82, positioning protrusions 86a and 86b are provided at corners close to the fuel gas supply communication hole 40a and corners close to the fuel gas discharge communication hole 40b, respectively. The protrusions 86a and 86b have a substantially triangular shape when viewed from the front, and are provided integrally with the base portions 60a and 60b.

  A triangular concave portion 88a for fitting the protruding portion 86a is formed at the inner corner of the fastening member 84a. A triangular concave portion 88b for fitting the protruding portion 86b is formed at the inner corner of the fastening member 84c.

  In the second embodiment configured as described above, the same effects as those of the first embodiment can be obtained, and under the engaging action of the projecting portions 86a and 86b having a triangular shape and the concave portions 88a and 88b. In addition, there is an advantage that the displacement of the fuel cell 82 is suppressed as much as possible.

  FIG. 7 is an exploded perspective view of a main part of a fuel cell 92 constituting a fuel cell stack 90 according to the third embodiment of the present invention.

  The fuel cell 92 has a vertically long rectangular shape, and an electrolyte membrane / electrode structure 94 is sandwiched between an anode side separator 96 and a cathode side separator 98. The upper end edge of the fuel cell 92 in the arrow C direction (vertical direction) communicates with each other in the direction of arrow B, which is the stacking direction, and the oxidant gas supply communication hole 36a, the cooling medium supply communication hole 38a, and the fuel gas supply communication. The holes 40a are arranged in the direction of arrow A. A fuel gas discharge communication hole 40b, a cooling medium discharge communication hole 38b, and an oxidant gas discharge communication hole 36b communicate with each other in the arrow B direction at the lower edge of the fuel cell 92 in the arrow C direction. Arranged and provided.

  A fuel gas passage 42 through which fuel gas flows along the vertical direction is formed on a surface 96 a of the anode separator 96 facing the electrolyte membrane / electrode structure 94. An oxidant gas passage 46 through which an oxidant gas flows along the vertical direction is formed on the surface 98a of the cathode side separator 98 facing the electrolyte membrane / electrode structure 94. Between the surface 96b of the anode-side separator 96 and the surface 98b of the cathode-side separator 98, a cooling medium flow path 44 that allows the cooling medium to flow along the vertical direction is formed.

  The electrolyte membrane / electrode structure 94 includes an MEA main body 100 and a resin frame member 102. The MEA main body 100 includes a solid polymer electrolyte membrane 52, and a cathode electrode 54 and an anode electrode 56 that sandwich the solid polymer electrolyte membrane 52. The resin frame member 102 is joined to and integrated with the outer peripheral portion of the MEA main body 100.

  The resin frame member 102 is made of, for example, PP (polypropylene), ABS (acrylonitrile butadiene styrene), or the like. Specifically, positioning protrusions 104a and 104b are provided at corners of the resin frame member 102, specifically at corners close to the fuel gas supply communication hole 40a and corners close to the fuel gas discharge communication hole 40b, respectively. Are provided integrally. The protrusions 104a and 104b are fitted into the concave portions 62a and 62b of the fastening members 24a and 24c.

  In the fuel cell stack 90 configured as described above, the protrusions 104 a and 104 b are provided on the resin frame member 102 constituting the electrolyte membrane / electrode structure 94. The protrusions 104a and 104b are fitted into the recessed portions 62a and 62b of the fastening members 24a and 24c, so that the fuel cells 92 are positioned and held.

  For this reason, in 3rd Embodiment, the effect similar to said 1st Embodiment is acquired. Note that the protruding portions 86a and 86b and the recessed portions 88a and 88b of the second embodiment can be employed instead of the protruding portions 104a and 104b and the recessed portions 62a and 62b.

DESCRIPTION OF SYMBOLS 10, 80, 90 ... Fuel cell stack 12, 82, 92 ... Fuel cell 14 ... Laminated body 20a, 20b ... End plate 24a-24d, 84a-84d ... Fastening member 30, 94 ... Electrolyte membrane and electrode structure 32, 34 96, 98 ... separator 36a ... oxidant gas supply communication hole 36b ... oxidant gas discharge communication hole 38a ... cooling medium supply communication hole 38b ... cooling medium discharge communication hole 40a ... fuel gas supply communication hole 40b ... fuel gas discharge communication hole DESCRIPTION OF SYMBOLS 42 ... Fuel gas flow path 44 ... Cooling medium flow path 46 ... Oxidant gas flow path 52 ... Solid polymer electrolyte membrane 54 ... Cathode electrode 56 ... Anode electrode 58a, 58b, 86a, 86b, 104a, 104b ... Projection part 60a, 60b ... Base part 62a, 62b, 88a, 88b ... Concave part 100 ... MEA main body part 102 ... Resin frame member

Claims (2)

A fuel cell in which an electrolyte / electrode structure provided with a pair of electrodes on both sides of an electrolyte and a separator are stacked, and a plurality of the fuel cells are stacked, and end plates are disposed at both ends in the stacking direction, A fuel cell stack in which end plates are fastened by a plurality of fastening members,
The fuel cell is provided with one or more protrusions protruding in a direction intersecting the stacking direction,
The fuel cell stack, wherein the at least one fastening member is formed with a concave portion in which the protruding portion is accommodated. 2. The fuel cell stack according to claim 1, wherein the fuel cell is provided with a fuel gas communication hole through which fuel gas flows at least along the stacking direction and an oxidant gas communication hole through which oxidant gas flows.
The fuel cell stack, wherein the protrusion is disposed in the vicinity of the fuel gas communication hole.

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