JP2022079927A - Fuel battery stack - Google Patents

Abstract

To provide a fuel battery stack capable of holding an insulation quality while suppressing a blockage of a gas passage.SOLUTION: A fuel battery stack in which a plurality of fuel batteries is laminated, includes: a first separator in which a gas introduction part and/or a gas conduction part are/is formed in vicinity of a manifold; an insulation sheet; and a second separator in this order. A space between the fuel battery cells is bonded with a pressure sensitive adhesive sheet having the insulation quality. A length to an external direction of the fuel battery cell of each member in the manifold is set so as to be shown in the following order: the pressure sensitive adhesive sheet>the first separator>the insulation sheet>the second separator.SELECTED DRAWING: Figure 4

Description

The present invention relates to a fuel cell stack.

A fuel cell is generally formed by stacking a single cell comprising a pair of separators and a membrane electrode assembly disposed between the pair of separators. In such a fuel cell, fuel gas is supplied to one of the flow paths formed between the membrane electrode assembly and the pair of separators, and oxidation gas is supplied to the other flow path. To generate electricity. Therefore, it is necessary to ensure sufficient sealing performance in each of the flow paths formed between the membrane electrode assembly and the pair of separators. As a structure for ensuring the sealing property of the flow path in the fuel cell, a configuration in which a frame-shaped resin sheet is conventionally arranged between a pair of separators so as to surround a membrane electrode assembly to be a power generator has been proposed. Has been done.

In Patent Document 1, in a fuel cell using a resin sheet, a resin sheet between separators is extended from the end of the membrane electrode gas diffusion layer junction to the vicinity of the manifold in order to suppress a short circuit caused by the intrusion of conductive foreign matter. It is disclosed that it will be issued.
Further, Patent Document 2 discloses that an insulating member is provided at the end of the separator in the vicinity of the manifold in order to enable expansion / contraction absorption in the separator stacking direction in the fuel cell stack.

Japanese Unexamined Patent Publication No. 2018-129213 Japanese Unexamined Patent Publication No. 2004-047495

As in Patent Document 1, a pair of structures for ensuring the sealing property of the oxide gas, the fuel gas, (hereinafter, the oxide gas and the fuel gas are also referred to as reaction gas) in the fuel cell and the flow path of the refrigerant. In a fuel cell stack in which an insulating sheet formed of a resin or the like is arranged between the separators of the fuel cell, the insulating sheet in the fuel cell is extended to the inner peripheral side of the manifold. It prevents a short circuit between them.

However, as in the comparative example shown in FIG. 7, when the insulating sheet 22 is extended to the inner peripheral side of the manifold in order to prevent a short circuit between the fuel cell, the reaction gas is introduced as shown by the broken line arrow G. Then, since the amount of protrusion of the insulating sheet 22 in the gas lead-in / inlet portion 50 is large, the insulating sheet 22 may be bent or curled due to the flow velocity of the gas or the like, and the extended insulating sheet 22 may block the gas out-source / inlet portion. There is. An adhesive sheet 62 is arranged between the fuel cell cells.

Therefore, in view of the above circumstances, an object of the present application is to provide a fuel cell stack that prevents a short circuit between fuel cell cells while suppressing blockage of a gas lead-in / inlet portion.

The present application is a fuel cell stack in which a plurality of fuel cell cells are stacked as one means for solving the above problems, and the fuel cell has a gas introduction portion and / or a gas lead-out portion formed in the vicinity of the manifold. The first separator, the insulating sheet, and the second separator are provided in this order, and the fuel cell cells are bonded to each other by an insulating adhesive sheet, and each member of the manifold is directed toward the outside of the fuel cell. The length discloses a fuel cell stack characterized in the following order:
Adhesive sheet> First separator> Insulation sheet> Second separator

According to the fuel cell stack of the present disclosure, it is not necessary to extend the insulating sheet to the inner peripheral portion of the manifold so as to block the gas flow path of the separator. Since the space is bonded with an adhesive sheet having an insulating property extending from the separator, short-circuiting between fuel cell cells can be prevented and electrical insulation can be maintained.

It is external perspective view of the fuel cell stack 1000 which concerns on embodiment of this invention. It is a schematic view of the fuel cell 100 and the adhesive sheet 60 to be laminated, FIG. 2A is an exploded external perspective view, and FIG. 2B is a laminated plan view. It is an exploded plan view of the fuel cell 100. It is a BB sectional view in FIG. 2B schematically showing the vicinity of the gas derivation inlet portion 50. FIG. 5A is an external perspective view of the vicinity of the gas lead-in / inlet portion 50 as seen from FIG. 4C. FIG. 5B is a sectional view taken along the line AA in FIG. 2B, schematically showing the outer peripheral portion of the fuel cell 100. It is sectional drawing which shows typically the other aspect in the vicinity of a gas derivation inlet part 50. It is a figure explaining the gas derivation entry part of the comparative example by the same cross section as the BB cross section of FIG. 2 (b).

[Fuel cell stack]
Hereinafter, the fuel cell stack 1000 according to the embodiment of the present invention will be described with reference to the drawings. However, the scope of the present invention is not limited to the embodiments described below. FIG. 1 is an external perspective view of the fuel cell stack 1000. 2A and 2B are schematic views of the fuel cell 100 and the adhesive sheet 60 to be laminated, FIG. 2A is an exploded external perspective view, and FIG. 2B is a laminated plan view. As shown in FIGS. 1 and 2, the fuel cell stack 1000 is a general fuel cell stack, and a plurality of fuel cell cells 100 are stacked to form a stack structure. In forming the stack structure, an adhesive sheet 60 is arranged between the fuel cell 100.

<Fuel cell>
FIG. 3 is a plan view of the fuel cell 100 according to the embodiment of the present invention, which is disassembled in the stacking direction. As shown in FIG. 3, the fuel cell 100 is in contact with the power generation body 10 including the membrane electrode assembly between the pair of separators 70 and 80 and the pair of separators 70 and 80, and the outer periphery of the power generation body 10. It is provided with an arranged insulating sheet 20.

(Generator)
The power generation body 10 includes an electrolyte membrane, a catalyst layer formed adjacent to both sides of the electrolyte membrane, and a gas diffusion layer. The electrolyte membrane is a solid polymer thin film that exhibits good proton conductivity in a wet state. The electrolyte membrane is composed of, for example, an ion exchange membrane of a fluororesin. The catalyst layer includes a catalyst that promotes a chemical reaction between hydrogen and oxygen, and carbon particles that carry the catalyst. The electrolyte membrane and the catalyst layer are collectively referred to as a membrane electrode assembly (MEA (Membrane Electrode Assembly)).

The gas diffusion layer is a layer provided adjacent to the surface on the catalyst layer side to diffuse the reaction gas used for the electrode reaction along the surface direction of the electrolyte membrane, and is a porous base material for the diffusion layer. It is composed of. As the base material for the diffusion layer, a porous base material having conductivity and gas diffusivity such as a carbon fiber base material, a graphite fiber base material, and a foamed metal is used. The electrolyte membrane, catalyst layer, and gas diffusion layer are collectively referred to as a membrane electrode gas diffusion layer assembly (MEGA (Membrane Electrode Gass-diffusion-layer Assembly)).

(Insulating sheet)
The insulating sheet 20 is a frame-shaped insulating member joined around the power generation body 10, and a known material having an insulating property can be used without limitation. For example, a resin sheet (resin frame) made of resin can be used. Also known as). Examples of the material constituting the resin sheet include polypropylene (PP), polyethylene naphthalate (PEN), polyphenylene sulfide (PPS), polyphenylene ether (PPE) and the like. These resins may be one type or a plurality of types may be laminated to form a resin sheet. The thickness of the insulating sheet 20 is not particularly limited, but is about 0.05 to 0.30 mm. In addition, in order to adhere to the separator or the like, both sides of the insulating sheet 20 may be coated with an adhesive modified polyolefin, a thermosetting adhesive, an adhesive or the like. The insulating sheet 20 has a substantially rectangular shape, has an opening for surrounding and accommodating the power generation body 10 in the central region thereof, and has manifold holes 30 and 31 in the vicinity of the outer periphery thereof.

(Separator)
The power generation body 10 and the insulating sheet 20 are arranged so as to be sandwiched from both sides in the stacking direction by a pair of separators composed of the separators 70 and 80. The separators 70 and 80 are substantially rectangular members, and manifold holes 30 and 31 are provided in the vicinity of the outer periphery thereof. Further, the separators 70 and 80 have irregularities (grooves) formed by press molding or the like, and the irregularities form an oxidation gas flow path, a fuel gas flow path, and a refrigerant flow path in the fuel cell 100. Examples of the materials of the separators 70 and 80 include stainless steel, titanium, carbon composite material and the like.
In the present embodiment, the first separator is a separator 70 having a gas lead-in / inlet section 50 in the pair of separators, introducing the reaction gas from the manifold hole 30 through the general gas lead-in / inlet section 50, and supplying / discharging the reaction gas to the power generation body 10. .. Further, the separator 80 arranged on the opposite side of the power generation body 10 with respect to the separator 70 is the second separator. That is, the first separator is a separator having a gas introduction section and / or a gas lead-out section, and is arranged on either the anode side forming the oxidation gas flow path or the cathode side forming the fuel gas flow path. May be.

<Adhesive sheet 60>
The adhesive sheet 60 is provided between the adjacent fuel cell 100 between the first separator 70 of one fuel cell 100 and the second separator 80 of the other fuel cell 100. An inter-cell refrigerant flow path is formed between the fuel cell 100, and the inter-cell refrigerant flow path is maintained in a sealing property by the adhesive sheet 60.
As shown in FIG. 2, the adhesive sheet 60 is a substantially rectangular insulating member, and has openings in the vicinity of the manifold in the central region and the outer peripheral portion thereof. As the material constituting the pressure-sensitive adhesive sheet, a known material having an insulating property can be used without limitation, and examples thereof include rubber-based, acrylic-based, and silicon-based pressure-sensitive adhesives, and the adhesive surface thereof is adhered. It may be coated with a sex-modified silicone, a thermosetting adhesive, an adhesive or the like. The thickness of the pressure-sensitive adhesive sheet 60 is not particularly limited, but may be about 0.15 to 0.8 mm.

<Manifold>
As shown in FIGS. 1 to 3, the adhesive sheet 60, the separator 70, the insulating sheet 20, and the separator 80 have manifolds at positions overlapping each other in the stacking direction of the fuel cell 100 in the vicinity of the outer periphery of each member. Manifold holes 30 and 31 for forming are provided. The manifold is a flow path through which the adhesive sheet 60, the separator 70, the insulating sheet 20, and the separator 80 flow, and the reaction gas or the refrigerant flows. The manifold hole 30 forms a flow path for supplying and discharging the reaction gas in the fuel cell 100. Fuel gas is supplied to one of the flow paths formed between the power generation body 10 and the pair of separators, and oxidation gas is supplied to the other flow path to generate electric power. Further, the manifold hole 31 forms a flow path for supplying and discharging the refrigerant to and from the refrigerant flow path formed between the fuel cell 100. Although the manifold holes 30 and 31 are substantially rectangular in FIGS. 1 to 3, they may be triangular, polygonal, or irregularly shaped manifold holes.

FIG. 4 is shown on the line BB of FIG. 2B, more specifically, the line BB of FIG. It is a cross-sectional view along. In FIG. 4, the adhesive sheet 60 and the fuel cell 100 are laminated in two layers. The arrow G indicates the flow in which the reaction gas is introduced from the manifold to the gas lead-in / inlet section 50. As shown in FIG. 4, in the vicinity of the manifold, the separator 70, the insulating sheet 20, and the separator 80 on which the gas lead-in / inlet portion 50 is formed are laminated in this order, and the fuel cell 100 is bonded with an insulating adhesive sheet 60. Has been done. Further, the length of each member of the manifold toward the outside of the fuel cell 100, that is, the length toward the inner peripheral side of the manifold is in the order of adhesive sheet 60> separator 70> insulating sheet 20> separator 80. The length of each member may be as long as the above relationship is maintained, and the length is not particularly limited. However, for example, from the viewpoint of preventing a short circuit between fuel cell cells, the length extends from the separator 70 of the adhesive sheet 60. The D1 is about 0.5 to 1 mm. Further, from the viewpoint of preventing the gas flow path from being blocked, the insulating sheet 20 may have a length that does not block the gas outlet / inlet portion 50 of the separator 70, but for example, the outside where the separator 70 and the insulating sheet 20 are in contact with each other. The length D2 of the insulating sheet 20 extending from the side end is about 0.2 to 1 mm. Further, the length D3 of the insulating sheet 20 extending from the separator 80 may be about 0.2 to 1 mm.

FIG. 5 (a) is an external perspective view of the gas lead-in / inlet portion 50 when FIG. 4 is viewed from C. As shown in FIG. 5A, the gas lead-in / inlet portion 50 formed in the separator 70 is composed of a plurality of elongated gas supply / discharge paths extending from the vicinity of the outer periphery of the manifold hole 30 toward the power generation body 10. That is, a plurality of gas supply / discharge paths are arranged in the depth direction of the cross-sectional view of FIG.

In the above embodiment, the case where the reaction gas is introduced from the manifold hole 30 into the generator 10 through the gas lead-in / inlet portion 50 of the separator 70 has been shown, but the reaction gas is introduced from the generator 10 through the gas lead-in / inlet portion 50 of the separator 70 into the manifold hole. Even when the gas is led out to 30, by providing the same configuration of each member as in the above embodiment, it is possible to prevent a short circuit between the fuel cell while suppressing the blockage of the gas lead-in / inlet portion 50.

FIG. 5B is a sectional view taken along the line AA in FIG. 2B, schematically showing the outer peripheral portion of the fuel cell 100. As shown in FIG. 5B, the pressure-sensitive adhesive sheet 60 preferably has a sealing property and a tolerance absorption stroke. Tolerance absorption stroke is to absorb dimensional variation with an elastic adhesive sheet.

<Other embodiments>
In the above embodiment, as shown in FIG. 4, the adhesive sheet 60 is provided so as to extend from the vicinity of the outer periphery of the power generation body 10 to the vicinity of the manifold in the outward direction of the separator 70 and continuously cover the adhesive sheet 60. good. FIG. 6 is a cross-sectional view similar to FIG. 4 showing another aspect of the gas lead-in / inlet section 50. The material of the insulating sheet 21 is the same as that of the insulating sheet 20. As shown in FIG. 6, since it is the same as the above embodiment except that the length and thickness of the insulating sheet 21 and the adhesive sheet 61 have a different length from the adhesive sheet 60, only the following differences are made. Describe. The insulating sheet 21 may extend beyond the separator 70 toward the outside of the fuel cell 100, and from the viewpoint of preventing a short circuit between the fuel cell cells, the length extending from the separator 70 of the adhesive sheet 61 is D1. The same degree can be mentioned. Similarly, from the viewpoint of preventing short circuits between fuel cell cells, the end portion of the insulating sheet 21 located on the power generation body 10 side has a plane region overlapping with the insulating sheet 20 as shown in FIG. 6, that is, The length D4 indicating the overlap between the insulating sheet 21 and the insulating sheet 20 is preferably 0 or more, and for example, about 0 to 0.2 mm can be mentioned. Further, the thickness of the insulating sheet 21 may be about 0.02 to 0.3 mm. The adhesive sheet 61 may be intermittently arranged on the separator 70 with respect to the insulating sheet 21 as long as the fuel cell cells can be adhered to each other.

According to the fuel cell stack of the present disclosure, since it is not necessary to extend the insulating sheet to the inner peripheral portion of the manifold so as to block the gas flow path of the separator, it is possible to prevent the gas lead-in / inlet portion from being blocked, and further, the fuel cell. By adhering the space with an adhesive sheet having an insulating property extending beyond the separator, short-circuiting between the fuel cell cells can be prevented and the insulating property can be maintained.

As described above, as described above, the fuel cell stack of the present disclosure is described using the fuel cell stack 1000 of one embodiment, and the technique of the present disclosure can be an important technique in the field of the fuel cell. Although the technique of the present disclosure can be applied to any fuel cell field, it is preferably an in-vehicle fuel cell.

10 Generator 20, 21 Insulation sheet 30, 31 Manifold 50 Gas lead-in / inlet 70 Separator 80 Separator 60, 61, 62 Adhesive sheet 100 Fuel cell cell 1000 Fuel cell stack

Claims (1)

A fuel cell stack in which multiple fuel cell cells are stacked.
The fuel cell has a first separator, an insulating sheet, and a second separator in which a gas introduction portion and / or a gas lead-out portion is formed in the vicinity of the manifold, and the fuel cell cells have an insulating property. A fuel cell stack that is bonded with an adhesive sheet and has the lengths of each member of the manifold toward the outside of the fuel cell in the following order.
Adhesive sheet> First separator> Insulation sheet> Second separator

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