JP5634978B2 - Fuel cell stack - Google Patents

Description

  The present invention includes a laminate in which a power generation cell having an electrolyte / electrode structure in which electrodes are arranged on both sides of an electrolyte and a separator is laminated, and a terminal plate and the terminal on both sides in the lamination direction of the laminate The present invention relates to a fuel cell stack in which an insulating plate and an end plate having a larger outer dimension than a plate are disposed.

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

  Usually, the fuel cell stack includes a stacked body in which a predetermined number of power generation cells are stacked, and a terminal plate, an insulating plate, and an end plate are disposed on both sides in the stacking direction of the stacked body.

  For example, in the fuel cell stack disclosed in Patent Document 1, a terminal plate, an insulating plate, and an end plate are disposed on both sides in the stacking direction of the stack, and the insulating plate has a recess in the center. The terminal plate is accommodated in the recess. Furthermore, an air chamber is formed between the inner wall surface of the recess and the outer peripheral surface of the terminal plate, and the air chamber functions as a heat insulating layer and can suppress heat dissipation from the terminal plate. Yes.

JP 2005-285402 A

  By the way, as described above, since the recess is provided in the insulating plate, there is a tolerance in the groove depth dimension of the recess, and there is also a tolerance in the thickness of the terminal plate itself. Therefore, the step size, which is a dimensional difference between the surface position of the terminal plate and the surface position of the insulating plate located on the outer periphery of the terminal plate, varies.

  For this reason, in the sealing member disposed between the separator at the end in the stacking direction and the insulating plate and in contact with the surface of the insulating plate, the seal line pressure may vary due to the variation in the step size. Accordingly, a desired stack tightening load cannot be reliably applied to the fuel cell stack, and there is a problem that stack performance such as power generation efficiency is lowered.

  The present invention solves this type of problem, and can improve the stack performance such as power generation efficiency by adjusting the step size and optimizing the seal line pressure with a simple and economical configuration. An object is to provide a fuel cell stack.

The present invention comprises a laminate power generation cell having a separator and the electrolyte electrode structure on both sides in the electrode is disposed in the electrolyte is laminated to both sides in the laminating direction of the laminated body, terminal plate, insulation is disposed is plate and end plate, said insulating plate and said end plate has a larger outside dimension than the terminal plate, and the terminal plate is in a fuel cell stack wherein Ru is received in the recess of the insulating plate is there.

In this fuel cell stack, a seal member is interposed between the at least one insulating plate and the end separator disposed at one end in the stacking direction of the stack so as to go around the outer peripheral end of the terminal plate. The end separator is a metal separator in which the seal member is integrally formed, and the insulating plate is provided with the convex seal portion in order to adjust the linear pressure of the convex seal portion of the seal member. A thickness adjusting shim member that is in contact with is disposed .

  In this fuel cell stack, it is preferable that the end separator and the separator constituting the power generation cell share a metal separator integrally formed with a seal member.

Furthermore, in this fuel cell stack, the thickness adjusting shim member is preferably disposed in the other recess formed by circling a concave portion on insulation plate.

  Furthermore, in this fuel cell stack, it is preferable that the thickness adjusting shim member includes an adjusting screw whose position can be adjusted in the stacking direction with respect to the surface of the insulating plate on the stacked body side.

  According to the present invention, the step size between the surface position of the terminal plate and the surface position of the insulating plate that circulates around the outer peripheral end of the terminal plate is adjusted to the thickness with which the seal member disposed on the end separator side abuts. It can be adjusted by the shim member.

  For this reason, it becomes possible to suppress the fluctuation | variation of a level | step difference dimension favorably, and the seal linear pressure of an edge part separator can be adjusted. Accordingly, it is possible to improve the stack performance such as power generation efficiency by adjusting the step size well and optimizing the seal line pressure with a simple and economical configuration.

1 is a partially exploded schematic perspective view of a fuel cell stack according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the fuel cell stack taken along line II-II in FIG. 1. It is a disassembled perspective explanatory drawing of the power generation cell which comprises the said fuel cell stack. It is front explanatory drawing of the 1st metal separator which comprises the said electric power generation cell. It is front explanatory drawing of the 2nd metal separator which comprises the said electric power generation cell.

  As shown in FIGS. 1 and 2, the fuel cell stack 10 according to the embodiment of the present invention includes a stacked body 14 in which a plurality of power generation 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 arranged at one end in the stacking direction (arrow A direction) of the stack 14 (see FIG. 1). 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 (see FIGS. 1 and 2).

  The fuel cell stack 10 is, for example, integrally held by a box-like casing (not shown) including end plates 20a, 20b configured in a square shape as end plates, or a plurality of tie rods extending in the direction of arrow A (Not shown) are integrally clamped and held.

  As shown in FIG. 3, the power generation cell 12 includes an electrolyte membrane / electrode structure 22, and a first metal separator 24 and a second metal separator 26 that sandwich the electrolyte membrane / electrode structure 22. The first metal separator 24 and the second metal separator 26 are composed of, for example, a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, or a metal plate that has been subjected to a surface treatment for anticorrosion on its metal surface. A carbon separator may be used. The metal plate is formed by pressing a metal thin plate into a wave shape.

  The electrolyte membrane / electrode structure 22 includes, for example, a solid polymer electrolyte membrane 28 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode electrode 30 and a cathode electrode 32 sandwiching the solid polymer electrolyte membrane 28. Prepare. The anode electrode 30 has a smaller surface area than the cathode electrode 32 and the solid polymer electrolyte membrane 28.

  The cathode electrode 32 may have a smaller surface area than the anode electrode 30 and the solid polymer electrolyte membrane 28, and the anode electrode 30, the cathode electrode 32, and the solid polymer electrolyte membrane 28 are They may have the same surface area.

  The anode electrode 30 and the cathode electrode 32 are formed by uniformly applying a gas diffusion layer (not shown) made of carbon paper or the like and porous carbon particles carrying a platinum alloy on the surface thereof to the surface of the gas diffusion layer. And an electrode catalyst layer (not shown) to be formed. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 28.

  One end edge of the power generation cell 12 in the direction of arrow B (the horizontal direction in FIG. 3) communicates with each other in the direction of arrow A, which is the stacking direction, and oxidant for supplying an oxidant gas, for example, an oxygen-containing gas An agent gas inlet communication hole 34a, a cooling medium inlet communication hole 36a for supplying a cooling medium, and a fuel gas outlet communication hole 38b for discharging a fuel gas, for example, a hydrogen-containing gas, are provided in the arrow C direction (vertical direction). Arranged and provided.

  The other end edge of the power generation cell 12 in the direction of arrow B communicates with each other in the direction of arrow A, a fuel gas inlet communication hole 38a for supplying fuel gas, and a cooling medium outlet communication hole for discharging the cooling medium. 36b and an oxidizing gas outlet communication hole 34b for discharging the oxidizing gas are arranged in the direction of arrow C.

  As shown in FIG. 4, a fuel gas flow path 40 extending in the direction of arrow B is formed on the surface 24 a of the first metal separator 24 facing the electrolyte membrane / electrode structure 22. The first metal separator 24 has a plurality of supply hole portions 42a for communicating the fuel gas inlet communication hole 38a with the fuel gas flow path 40, and the fuel gas flow path 40 for communicating with the fuel gas outlet communication hole 38b. A plurality of discharge hole portions 42b are formed.

  As shown in FIG. 3, for example, an oxidant gas flow path 44 extending in the direction of arrow B is provided on the surface 26 a of the second metal separator 26 facing the electrolyte membrane / electrode structure 22. The oxidant gas passage 44 communicates with the oxidant gas inlet communication hole 34a and the oxidant gas outlet communication hole 34b.

  A cooling medium flow path 46 communicating with the cooling medium inlet communication hole 36a and the cooling medium outlet communication hole 36b is formed between the surface 24b of the first metal separator 24 and the surface 26b of the second metal separator 26 adjacent to each other. Is done. This cooling medium flow path 46 extends in the direction of arrow B, for example.

  As shown in FIGS. 3 to 5, the first seal member 48 is integrated with the surfaces 24 a and 24 b of the first metal separator 24 around the outer peripheral end of the first metal separator 24. The second seal member 50 is integrated with the surfaces 26 a and 26 b of the second metal separator 26 around the outer peripheral end of the second metal separator 26.

  The first seal member 48 and the second seal member 50 include, for example, EPDM, NBR, fluorine rubber, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene or acrylic rubber, and cushioning materials. Or a packing material is used.

  As shown in FIG. 4, the first seal member 48 has a convex seal portion 48 a that is integrally formed with the surface 24 a of the first metal separator 24. The convex seal portion 48a protrudes from the planar seal portion 48b and surrounds (covers) the outer periphery of the fuel gas flow path 40, the supply hole portion 42a, and the discharge hole portion 42b.

  As shown in FIGS. 2 and 3, the first seal member 48 includes a planar seal portion 48 c that is integrally formed with the surface 24 b of the first metal separator 24. The planar seal portion 48c is provided with communication passages 52a and 52b that communicate the cooling medium flow path 46 with the cooling medium inlet communication hole 36a and the cooling medium outlet communication hole 36b.

  The second seal member 50 has a convex seal portion 50a formed integrally with the surface 26a of the second metal separator 26, and the convex seal portion 50a is formed to protrude from the planar seal portion 50b. The convex seal portion 50 a goes around the outer peripheral edge of the surface 26 a and communicates the oxidant gas inlet communication hole 34 a and the oxidant gas outlet communication hole 34 b to the oxidant gas flow path 44. The planar seal portion 50 b is provided with communication passages 54 a and 54 b that communicate the oxidant gas inlet communication hole 34 a and the oxidant gas outlet communication hole 34 b with the oxidant gas flow path 44.

  As shown in FIG. 5, the second seal member 50 integrally molds the inner convex seal portion 50 c and the outer convex seal portion 50 d on the surface 26 b of the second metal separator 26. The inner convex seal portion 50c and the outer convex seal portion 50d are formed so as to protrude from the planar seal portion 50e.

  The inner convex seal portion 50c is provided to cover the cooling medium flow path 46, the cooling medium inlet communication hole 36a, and the cooling medium outlet communication hole 36b. The cooling medium flow path 46 communicates with the cooling medium inlet communication hole 36a and the cooling medium outlet communication hole 36b through communication passages 56a and 56b.

  As shown in FIG. 1, terminal portions 58a and 58b extending outward in the stacking direction are provided at substantially the center of the terminal plates 16a and 16b. The terminal portions 58a and 58b are inserted into the insulating cylindrical body 60 and penetrate the hole portions 62a and 62b of the insulating plates 18a and 18b and the hole portions 64a and 64b of the end plates 20a and 20b, and the end plates 20a and 20b. Project outside.

  The insulating plates 18a and 18b are formed of an insulating material such as polycarbonate (PC) or phenol resin. The insulating plates 18a and 18b are provided with rectangular recesses 66a and 66b at the center, and holes 62a and 62b are formed at substantially the center of the recesses 66a and 66b. In the recesses 66a and 66b, the terminal plates 16a and 16b are accommodated so as to protrude from the surface 18bs of the insulating plates 18a and 18b, and the terminal portions 58a and 58b of the terminal plates 16a and 16b are interposed via the insulating cylinder 60. The holes 62a and 62b are inserted.

  As shown in FIG. 2, the outer peripheral end of the terminal plate 16 b is located between at least one insulating plate 18 b and the end metal separator 26 (end) disposed at one end in the stacking direction of the stacked body 14. The second seal member 50 is interposed around. The second seal member 50 abuts on a thickness adjusting shim member 68 in which the inner convex seal portion 50c and the outer convex seal portion 50d are disposed on the insulating plate 18b side. The shim member 68 is preferably formed of an insulating resin material. The end metal separator 26 (end) shares the same components as the second metal separator 26.

  As shown in FIG. 1, the shim member 68 has a frame shape (frame shape). As shown in FIG. 5, the inner convex seal portion 50 c of the second seal member 50 provided in the second metal separator 26. In addition, the size is set so as to contact the outer convex seal portion 50d. A plurality of holes 70 are formed in the shim member 68 at a predetermined depth from the insulating plate 18b side.

  In the insulating plate 18b, a recess 72 (second recess) is formed around the recess 66b (first recess). The recess 72 has a shape corresponding to the shim member 68 to accommodate the shim member 68, and the surface 68a of the shim member 68 protrudes inwardly (on the laminated body 14 side) from the surface 18bs of the insulating plate 18b. Is possible.

  As shown in FIG. 1, screw holes 74 are formed in the insulating plate 18 b coaxially with the holes 70 of the shim member 68 and located in the recess 72. An adjustment screw 76 is screwed into the screw hole 74, and the tip of the adjustment screw 76 is fitted into the hole 70 of the shim member 68. The adjustment screw 76 presses the shim member 68 to adjust the position of the shim member 68 in the stacking direction. The adjustment screw 76 can change the position adjustment amount of the shim member 68 by using the washer 78. Note that the thickness of the shim member 68 itself may be adjusted without using the adjusting screw 76.

  The insulating plate 18a and the end plate 20a include an oxidant gas inlet communication hole 34a, a cooling medium inlet communication hole 36a, a fuel gas outlet communication hole 38b, a fuel gas inlet communication hole 38a, a cooling medium outlet communication hole 36b, and an oxidant gas outlet. A communication hole 34b is formed.

  The operation of the fuel cell stack 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 34a of the end plate 20a. A fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 38a of the end plate 20a, while a cooling medium such as pure water, ethylene glycol, or oil is supplied to the cooling medium inlet communication hole 36a of the end plate 20a. Supplied.

  As shown in FIG. 3, the oxidant gas is introduced into the oxidant gas flow path 44 of the second metal separator 26 from the oxidant gas inlet communication hole 34a, moves in the direction of arrow B, and moves to the electrolyte membrane / electrode structure 22. The cathode electrode 32 is supplied.

  On the other hand, as shown in FIGS. 3 and 4, the fuel gas is introduced from the fuel gas inlet communication hole 38 a through the supply hole 42 a into the fuel gas flow path 40 of the first metal separator 24. The fuel gas moves in the direction of arrow B along the fuel gas flow path 40 and is supplied to the anode electrode 30 of the electrolyte membrane / electrode structure 22.

  Accordingly, in each electrolyte membrane / electrode structure 22, the oxidant gas supplied to the cathode electrode 32 and the fuel gas supplied to the anode electrode 30 are consumed by an electrochemical reaction in the electrode catalyst layer to generate power. Done.

  Next, the oxidant gas consumed by being supplied to the cathode electrode 32 is discharged in the direction of arrow A along the oxidant gas outlet communication hole 34b. Similarly, the fuel gas consumed by being supplied to the anode electrode 30 passes through the discharge hole portion 42b and is discharged in the direction of arrow A along the fuel gas outlet communication hole 38b.

  Further, the cooling medium supplied to the cooling medium inlet communication hole 36a was introduced into the cooling medium flow path 46 between the first metal separator 24 and the second metal separator 26, as shown in FIGS. Then, it circulates in the direction of arrow B. This cooling medium is discharged from the cooling medium outlet communication hole 36b after the electrolyte membrane / electrode structure 22 is cooled.

  In this case, in the present embodiment, as shown in FIG. 2, the second seal member 50 circulates around the outer peripheral end of the terminal plate 16b between the insulating plate 18b and the end metal separator 26 (end). It is intervened. In the second seal member 50, the inner convex seal portion 50c and the outer convex seal portion 50d are in contact with the shim member 68 disposed on the insulating plate 18b side.

  For this reason, the step size between the surface position of the terminal plate 16b and the surface position of the insulating plate 18b that goes around the outer peripheral end of the terminal plate 16b is the second seal disposed on the end metal separator 26 (end) side. The shim member 68 with which the member 50 abuts can be adjusted. Specifically, the step size is adjusted by changing the thickness of the shim member 68 in the stacking direction, the screwing amount of the adjusting screw 76, and the thickness of the washer 78 provided on the adjusting screw 76.

  Accordingly, it is possible to satisfactorily suppress the variation in the step size, and it is possible to adjust the seal line pressure of the end metal separator 26 (end). As a result, the fuel cell stack 10 has an effect that it is possible to improve the stack performance such as the power generation efficiency by adjusting the step size well and optimizing the seal linear pressure with a simple and economical configuration. can get.

  Moreover, the end metal separator 26 (end) is configured substantially the same as the second metal separator 26 that constitutes the power generation cell 12, and can share the second metal separator 26. For this reason, there is an advantage that the configuration of the entire fuel cell stack 10 is simplified and economical.

  The end separator may not be a separator used for power generation, but may be a separator that holds a dummy MEA.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell stack 12 ... Power generation cell 14 ... Laminated body 16a, 16b ... Terminal plate 20a, 20b ... End plate 22 ... Electrolyte membrane electrode assembly 24, 26 ... Metal separator 26 (end) ... End metal separator 28 ... Solid polymer electrolyte membrane 30 ... Anode electrode 32 ... Cathode electrode 40 ... Fuel gas channel 44 ... Oxidant gas channel 46 ... Cooling medium channels 48, 50 ... Seal members 50c, 50d ... Convex seal 68: Shim member 70 ... Hole 72 ... Recess 74 ... Screw hole 76 ... Adjustment screw 78 ... Washer

Claims (4)

Comprising a stack power generation cell having a separator and the electrolyte electrode structure on both sides in the electrode is disposed in the electrolyte is laminated to both sides in the laminating direction of the laminated body, terminal plate, insulation plate and an end plate there are disposed, the insulating plate and said end plate has a larger outside dimension than the terminal plate, and the terminal plate is a fuel cell stack that will be received in the recess of the insulating plate,
Between at least one of the insulating plates and an end separator disposed at one end in the stacking direction of the stacked body, a seal member is interposed around the outer peripheral end of the terminal plate, and
The end separator is a metal separator in which the seal member is integrally formed,
Wherein the insulating plate, in order to adjust the line pressure of the convex sealing portion of the sealing member, the fuel cell stack thickness adjusting shim member in which the convex seal portion abuts is characterized Rukoto disposed . The fuel cell stack according to claim 1, and the separator of the power generation cell and the end separator, a fuel cell stack, characterized by sharing the metal separator in which the sealing member is integrally molded. According to claim 1 or 2 fuel cell stack according before KiAtsu adjusting shim member may be disposed to other recess formed orbiting the front Ki凹 portion in the insulating plate Fuel cell stack.   The fuel cell stack according to any one of claims 1 to 3, wherein the thickness adjusting shim member includes an adjustment screw whose position can be adjusted in the stacking direction with respect to the surface of the insulating plate on the stacked body side. A fuel cell stack comprising:

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