JP5166982B2 - Fuel cell stack - Google Patents

Description

  The present invention provides a fuel cell stack having a unit cell in which an electrolyte / electrode structure having a pair of electrodes provided on both sides of an electrolyte is sandwiched between separators, and a plurality of unit cells stacked in the horizontal direction. About.

  For example, a polymer electrolyte fuel cell employs an electrolyte membrane (electrolyte) made of a polymer ion exchange membrane. A fuel cell is configured by sandwiching an electrolyte membrane / electrode structure in which an anode side electrode and a cathode side electrode are disposed on both sides of the electrolyte membrane with a separator. Normally, this fuel cell is used as a fuel cell stack in which a predetermined number (for example, several tens to several hundreds) is stacked in order to obtain a desired power generation.

  In this case, the separator is required to have air tightness and liquid tightness in order to prevent leakage of fuel gas, oxidant gas, and cooling medium. For this reason, for example, Patent Document 1 discloses a silicone resin-metal composite in which a seal member is integrally formed with a separator.

  In this prior art, as shown in FIG. 6, a unit cell 4 is configured by combining a separator 1, an electrode 2, and a spacer 3. In the separator 1, sealing materials 6 a and 6 b made of a silicone resin layer are integrally formed on both surfaces of the separator body 5, and convex ribs 7 are formed on the sealing material 6 a.

JP 11-129396 A

  By the way, the unit cell unit 4 has a fuel cell stack in which end members such as end plates are disposed at both ends in the stacking direction. At that time, when a load from the outside is applied to the fuel cell stack, the separators 1 can absorb the impact by the deformation of the sealing materials 6a and 6b.

  However, the end separator 1 arranged at the end in the stacking direction is adjacent to the end member that is a rigid body. For this reason, the end separator 1 itself may not have a sufficient shock absorbing function. Thereby, when the edge part separator 1 deform | transforms with an impact load, there exists a problem that the sealing performance by the sealing materials 6a and 6b falls.

  The present invention solves this type of problem, and has an object to provide a fuel cell stack capable of satisfactorily suppressing a decrease in sealing performance due to deformation of an end separator with a simple and economical configuration. And

  The present invention provides a fuel cell stack having a unit cell in which an electrolyte / electrode structure having a pair of electrodes provided on both sides of an electrolyte is sandwiched between separators, and a plurality of unit cells stacked in the horizontal direction. It is about.

  The end unit cell disposed at least at one end in the stacking direction of the laminate is provided with an end seal member between the end unit cells adjacent to the end unit cell, and the end seal member is formed of the laminate. The elastic modulus is set to be smaller than that of a seal member provided in another unit cell arranged inward.

  The end seal member is preferably provided in the end unit cell, and the end seal member is preferably set to have a larger dimension in the stacking direction than seal members provided in other unit cells.

  Further, the end seal member includes: a seal member provided in the end unit cell; and an elastic member provided in the end member adjacent to the end unit cell and in contact with the seal member of the end unit cell. It is preferable to have.

  Furthermore, the end member is preferably an end plate or an insulating plate.

  In the present invention, the end seal member provided between the end unit cell and the end member is set to have a smaller elastic modulus than the seal member provided in the other unit cell, so that an external load is applied. When this is done, the deformation amount of the end seal member becomes relatively large, and the impact load can be easily absorbed. As a result, it is possible to satisfactorily suppress a reduction in sealing performance due to the deformation of the end separator with a simple and economical configuration.

  FIG. 1 is a partially exploded schematic perspective view of a fuel cell stack 10 according to the first embodiment of the present invention, and FIG. 2 is a partial sectional side view of the fuel cell stack 10.

  The fuel cell stack 10 includes a stacked body 14 in which a plurality of unit cells 12 are stacked in the horizontal direction (arrow A direction). A terminal plate 16a, an insulating plate 18a, and an end plate 20a are sequentially disposed at one end in the stacking direction (arrow A direction) of the stacked body 14 toward the outside. At the other end in the stacking direction of the stacked body 14, a terminal plate 16b, an insulating plate 18b, and an end plate 20b are sequentially disposed outward. The fuel cell stack 10 is integrally held by a box-shaped casing 24 including end plates 20a and 20b configured as vertically long rectangles as end plates.

  As shown in FIGS. 2 and 3, each unit cell 12 includes an electrolyte membrane / electrode structure (electrolyte / electrode structure) 30, and a thin plate-shaped first and second sandwiching the electrolyte membrane / electrode structure 30. Second metal separators 32 and 34 are provided. The electrolyte membrane / electrode structure 30 and the first and second metal separators 32 and 34 are configured in a vertically long rectangular shape. Instead of the first and second metal separators 32 and 34, carbon separators may be used.

  In order to supply an oxidant gas, for example, an oxygen-containing gas, to one end edge (upper edge) in the long side direction (the arrow C direction in FIG. 3) of the unit cell 12 in communication with each other in the arrow A direction. The oxidant gas supply communication hole 36a and a fuel gas supply communication hole 38a for supplying a fuel gas, for example, a hydrogen-containing gas, are provided.

  The other end edge (lower end edge) of the unit cell 12 in the long side direction communicates with each other in the direction of arrow A, and discharges the fuel gas discharge communication hole 38b for discharging the fuel gas and the oxidant gas. For this purpose, an oxidant gas discharge communication hole 36b is provided.

  A cooling medium supply communication hole 40a for supplying a cooling medium is provided at one end edge of the unit cell 12 in the short side direction (arrow B direction), and the other end edge of the unit cell 12 in the short side direction. Is provided with a cooling medium discharge communication hole 40b for discharging the cooling medium.

  The electrolyte membrane / electrode structure 30 includes, for example, a solid polymer electrolyte membrane 42 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode side electrode 44 and a cathode side electrode 46 that sandwich the solid polymer electrolyte membrane 42. With.

  The anode side electrode 44 and the cathode side electrode 46 are uniformly coated with a gas diffusion layer (not shown) made of carbon paper or the like and porous carbon particles carrying a platinum alloy on the surface thereof. And an electrode catalyst layer (not shown) formed. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 42.

  On the surface 32a of the first metal separator 32 facing the electrolyte membrane / electrode structure 30, a fuel gas flow channel 48 that communicates the fuel gas supply communication hole 38a and the fuel gas discharge communication hole 38b is formed along the arrow C direction. Is done. On the surface 32b of the first metal separator 32, a cooling medium flow path 50 that communicates the cooling medium supply communication hole 40a and the cooling medium discharge communication hole 40b is formed along the arrow B direction.

  The surface 34a of the second metal separator 34 facing the electrolyte membrane / electrode structure 30 is provided with an oxidant gas flow path 52 along the direction of arrow C. The oxidant gas flow path 52 is provided with an oxidant gas supply. The communication hole 36a communicates with the oxidant gas discharge communication hole 36b. A cooling medium flow path 50 is integrally formed on the surface 34 b of the second metal separator 34 so as to overlap the surface 32 b of the first metal separator 32.

  A first seal member 54 is integrally formed on the surfaces 32 a and 32 b of the first metal separator 32 around the outer peripheral edge of the first metal separator 32. A second seal member 56 is integrally formed on the surfaces 34 a and 34 b of the second metal separator 34 around the outer peripheral edge of the second metal separator 34.

  As shown in FIG. 2, the end unit cell 12 a disposed at one end (on the end plate 20 a side) in the stacking direction of the stacked body 14 wraps around the outer peripheral edge of the first metal separator 32 and is an end seal member. 54a is provided. The end seal member 54a is preferably bonded to the terminal plate 16a (or the insulating plate 18a). This is because deviation can be prevented when an impact is applied, and leakage of fuel gas or oxidant gas can be prevented.

  The end seal member 54 a is set to have a smaller elastic modulus than the first seal member 54 provided in the unit cell 12 disposed inside the stacked body 14. That is, the end seal member 54 a has a larger deformation amount than the first seal member 54.

  In the first embodiment, the end seal member 54a is made of the same material as the first seal member 54, and the thickness t1 in the stacking direction (arrow A direction) of the end seal member 54a is a unit. It is set larger than the thickness t2 in the stacking direction of the first seal member 54 provided in the cell 12 (t1> t2).

  In addition, you may comprise the edge part unit cell 12b arrange | positioned in the lamination direction other end part of the laminated body 14 similarly to said edge part unit cell 12a. Further, the end seal member 54 a is made of a material different from that of the first seal member 54, so that it can be set to have the same thickness and a smaller elastic modulus than the first seal member 54.

  A seal 57 is interposed between the first and second seal members 54 and 56 in order to prevent the outer periphery of the solid polymer electrolyte membrane 42 from directly contacting the casing 24.

  As shown in FIG. 1, rod-shaped terminal portions 58a and 58b projecting in the stacking direction are provided on the center side of the terminal plates 16a and 16b. The terminal portions 58a and 58b protrude to the outside through holes 59a and 59b formed in the center portions of the end plates 20a and 20b in the longitudinal direction and the short direction, and the terminal portions 58a and 58b include, for example, A load such as a vehicle driving motor is connected.

  The casing 24 is an angle member that connects end plates 20a and 20b, which are end plates, a plurality of side plates 60a to 60d disposed on the side of the laminated body 14, and end portions of the side plates 60a to 60d that are close to each other. 62a to 62d, and connecting pins 64a and 64b having different lengths for connecting the end plates 20a and 20b and the side plates 60a to 60d.

  The side plates 60a to 60d are made of, for example, a thin metal plate. The side plates 60a to 60d are fixed to each other via angle members 62a to 62d and bolts 65, and the casing 24 is configured (see FIG. 4).

  On the upper and lower sides (short sides) of the end plates 20a and 20b, one first support portion 66a and 66b is formed to protrude, and on each side (long side) on both sides, two first supports are provided. Portions 66c and 66d are formed to protrude.

  Three second support portions 70a and 70b are formed at both ends in the longitudinal direction (arrow A direction) of the side plates 60a and 60c arranged on both sides in the arrow B direction of the laminated body 14, respectively. Two second support portions 72a and 72b are formed at both ends in the longitudinal direction of the side plates 60b and 60d disposed on the upper and lower sides of the laminated body 14, respectively.

  As shown in FIG. 4, between the second support portions 70a, 70b of the side plates 60a, 60c, first support portions 66c, 66d on both sides of the end plates 20a, 20b are arranged. A long connecting pin 64a is integrally inserted.

  Similarly, the second support portions 72a and 72b of the side plates 60b and 60d are alternately arranged with the first support portions 66a and 66b on the upper and lower sides of the end plates 20a and 20b, and a short connecting pin 64b is provided on these. Inserted integrally.

  As shown in FIG. 1, the end plate 20a has an oxidant gas inlet 76a communicating with the oxidant gas supply communication hole 36a, a fuel gas inlet 78a communicated with the fuel gas supply communication hole 38a, and an oxidant gas discharge communication hole 36b. An oxidant gas outlet 76b communicating with the fuel gas and a fuel gas outlet 78b communicating with the fuel gas discharge communicating hole 38b are provided.

  The end plate 20b is provided with a cooling medium inlet 80a that communicates with the cooling medium supply communication hole 40a and a cooling medium outlet 80b that communicates with the cooling medium discharge communication hole 40b.

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

  As shown in FIG. 4, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet 76a of the end plate 20a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet 78a. Further, a cooling medium such as pure water or ethylene glycol is supplied to the cooling medium inlet 80a of the end plate 20b.

  Therefore, in the stacked body 14, the oxidant gas is supplied to the oxidant gas supply communication hole 36a, the fuel gas supply communication hole 38a, and the cooling medium supply communication hole 40a with respect to the plurality of unit cells 12 stacked in the arrow A direction. The fuel gas and the cooling medium are supplied in the direction of arrow A.

  As shown in FIG. 3, the oxidant gas is introduced into the oxidant gas flow path 52 of the second metal separator 34 through the oxidant gas supply communication hole 36 a, and along the cathode side electrode 46 of the electrolyte membrane / electrode structure 30. Move. On the other hand, the fuel gas is introduced into the fuel gas channel 48 of the first metal separator 32 from the fuel gas supply communication hole 38 a and moves along the anode side electrode 44 of the electrolyte membrane / electrode structure 30.

  Therefore, in each electrolyte membrane / electrode structure 30, the oxidant gas supplied to the cathode side electrode 46 and the fuel gas supplied to the anode side electrode 44 are consumed by an electrochemical reaction in the electrode catalyst layer, Power generation is performed.

  Next, the oxidant gas consumed by being supplied to the cathode side electrode 46 flows along the oxidant gas discharge communication hole 36b, and is then discharged to the outside from the oxidant gas outlet 76b of the end plate 20a (FIG. 4). reference). Similarly, the fuel gas consumed by being supplied to the anode side electrode 44 is discharged to the fuel gas discharge communication hole 38b and flows, and is discharged to the outside from the fuel gas outlet 78b of the end plate 20a.

  The cooling medium is introduced into the cooling medium flow path 50 between the first and second metal separators 32 and 34 from the cooling medium supply communication hole 40a, and flows along the arrow B direction. After cooling the electrolyte membrane / electrode structure 30, the cooling medium moves through the cooling medium discharge communication hole 40b and is discharged from the cooling medium outlet 80b of the end plate 20b (see FIG. 1).

  In this case, for example, when an external load (impact) is applied to the fuel cell stack 10 in the stacking direction, each unit cell 12 deforms the first and second seal members 54 and 56 themselves or other adjacent cells. The impact can be absorbed by the deformation of the first and second sealing members 54 and 56 of the unit cell 12. On the other hand, the end unit cell 12a disposed at one end in the stacking direction of the stacked body 14 is in direct contact with a rigid terminal plate (end member) 16a, and a sufficient buffering effect by the other unit cells 12 is obtained. I can't.

  Therefore, in the first embodiment, the end seal member 54a is provided around the outer peripheral edge of the first metal separator 32 constituting the end unit cell 12a. At that time, the thickness t1 of the end seal member 54a in the stacking direction is set to be larger than the thickness t2 of the first seal member 54 provided in the unit cell 12 in the stacking direction (see FIG. 2).

  Therefore, when an impact is applied to the fuel cell stack 10 in the stacking direction, in the end unit cell 12a, the end seal member 54a provided in the first metal separator 32 is relatively opposed to the terminal plate 16a. It can be greatly deformed. As a result, the end seal member 54a can effectively absorb the impact load, and with a simple and economical configuration, it is possible to satisfactorily suppress the deterioration of the sealing performance due to the deformation of the first metal separator 32. The effect that it becomes possible is obtained.

  FIG. 5 is a partial cross-sectional side view of a fuel cell stack 90 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.

  The insulating plates 92a and 92b constituting the fuel cell stack 90 have recesses 94a and 94b on the inner surfaces thereof, and terminal plates 16a and 16b are accommodated in the recesses 94a and 94b.

  The end unit cell 12c disposed at one end portion (on the end plate 20a side) in the stacking direction of the stacked body 14 circulates around the outer peripheral edge of the first metal separator 32 and is a first seal member 54 that is an end seal member. Is provided. The insulating plate (end member) 92a is provided with an elastic member, for example, a rubber member 96, with which the first seal member 54 abuts. The first seal member 54 and the rubber member 96 constitute an end seal member 98.

  In the second embodiment configured as described above, the end unit cell 12c includes the same first and second seal members 54, 56 as the first and second seal members 54, 56 of the other unit cells 12. The first seal member 54 is in contact with the rubber member 96 to form an end seal member 98.

  Therefore, the first seal member 54 does not directly contact the rigid insulating plate 92a, and when the fuel cell stack 90 is subjected to an impact in the stacking direction, the first seal member 54 and the rubber member 96 are deformed. Under the action, the shock can be absorbed effectively. Thereby, with the simple and economical configuration, the same effects as those of the first embodiment described above can be obtained, for example, it is possible to satisfactorily suppress the deterioration of the sealing performance due to the deformation of the first metal separator 32.

  In the first embodiment, insulating plates 92a and 92b may be used instead of the insulating plates 18a and 18b.

1 is a partially exploded schematic perspective 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 disassembled perspective explanatory drawing of the unit cell which comprises the said fuel cell stack. It is a perspective view of the fuel cell stack. It is a partial cross section side view of the fuel cell stack concerning the 2nd Embodiment of the present invention. It is explanatory drawing of the cell unit of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 90 ... Fuel cell stack 12 ... Unit cell 12a-12c ... End unit cell 14 ... Laminated body 16a, 16b ... Terminal plate 18a, 18b ... Insulating plate 20a, 20b ... End plate 24 ... Casing 30 ... Electrolyte membrane electrode Structures 32, 34 ... Metal separator 42 ... Solid polymer electrolyte membrane 44 ... Anode side electrode 46 ... Cathode side electrode 48 ... Fuel gas passage 50 ... Cooling medium passage 52 ... Oxidant gas passage 54, 56 ... Seal member 54a, 98 ... end seal members 60a-60d ... side plates 64a, 64b ... connecting pins 92a, 92b ... insulating plates 96 ... rubber members

Claims (4)

A fuel cell stack comprising a unit cell in which a pair of electrodes are provided on both sides of an electrolyte, and a unit cell sandwiched by separators, and a stacked body in which a plurality of the unit cells are stacked in a horizontal direction,
The end unit cell disposed at least at one end in the stacking direction of the laminate is provided with an end seal member between the end unit cells adjacent to the end unit cell,
The fuel cell stack according to claim 1, wherein the end seal member is set to have a smaller elastic modulus than a seal member provided in another unit cell disposed inside the stacked body. The fuel cell stack according to claim 1, wherein the end seal member is provided in the end unit cell,
The fuel cell stack according to claim 1, wherein the end seal member is set to have a larger dimension in the stacking direction than a seal member provided in the other unit cell. 2. The fuel cell stack according to claim 1, wherein the end seal member is a seal member provided in the end unit cell.
An elastic member provided on the end member adjacent to the end unit cell, and in contact with the seal member of the end unit cell;
A fuel cell stack comprising:   The fuel cell stack according to any one of claims 1 to 3, wherein the end member is an end plate or an insulating plate.

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