JP5024503B2 - Fuel cell seal - Google Patents

Description

  The present invention relates to a fuel cell cell seal which is a constituent element of a fuel cell.

  Conventionally, as shown in FIG. 2, a membrane electrode assembly (MEA) 51 in which electrode layers (both not shown) are provided on both sides of an electrolyte membrane, and gas diffusion superimposed on both sides of the membrane electrode assembly 51 A cell seal for a fuel cell is known in which a gasket 53 is integrally formed (partially impregnated) on the outer peripheral portion of a layer (GDL) 52, and a pair of separators 54 and 54 are sealed by the gasket 53 (Patent Documents 1 and 2). reference).

  However, since the membrane electrode assembly 51 is in the form of a thin film, when exposed to the use environment, expansion (swelling) or contraction occurs in the plane direction. In addition, due to the characteristics of this membrane electrode assembly 51, when it is dried, gaps and deviations occur between the gasket 53 and the gas diffusion layer 52 due to further shrinkage, and the power generation efficiency of the fuel cell is caused by these. There are problems such as lowering.

  As shown in FIG. 3, a technique for providing a through hole 56 in the electrolyte membrane 55 of the membrane electrode assembly 51 has been developed as in the present invention (see Patent Document 3). The gas diffusion layer 52 is formed on the gasket 53, and the membrane electrode assembly 51 is bonded to the gasket 53 and the gas diffusion layer 52 by thermocompression bonding with the protective film 57.

  Therefore, according to this prior art, when manufacturing the protective film 57 having a limited material type, a process of attaching the protective film 57 in advance and a process of thermocompression bonding the protective film 57 and the gas diffusion layer 52 must be performed. There are inconveniences such as complicated manufacturing process. Further, according to this prior art, a gap 58 is formed between the gasket 53 and the gas diffusion layer 52, and the reaction gas easily flows through the gap 58, and the reaction gas flowing through the gap 58 hardly contributes to the power generation reaction. It is also possible to cause a decrease in

JP 2001-510932 A WO2002 / 043172 WO2002 / 061869

  In view of the above points, the present invention can suppress the occurrence of a gap or a gap between the membrane electrode assembly and the gas diffusion layer with a relatively simple configuration, thereby suppressing the reduction in power generation efficiency. An object of the present invention is to provide a cell seal for a fuel cell that can be used.

In order to achieve the above object, the cell seal for a fuel cell of the present invention has a membrane electrode assembly in which electrode layers are provided on both surfaces of an electrolyte membrane, and an outer peripheral portion of a gas diffusion layer superimposed on both surfaces of the membrane electrode complex. In a cell seal for a fuel cell in which a gasket for sealing between a pair of separators is fixed by integral molding, the outer periphery of the electrolyte membrane in the membrane electrode assembly protrudes outward from the outer periphery of the electrode layer and the gas diffusion layer. A projecting portion is provided, a through hole is provided in the projecting portion, the gasket is integrally formed around the projecting portion, and the gasket is impregnated with a part of the molding material in the outer peripheral portion of the gas diffusion layer. wherein is fixed to the gas diffusion layer is fixed to the electrolyte membrane by filling a portion of the molding material into the through hole, further wherein the gasket by, One surface side portion disposed on one surface side of the projecting portion, one surface side impregnation portion disposed inside the one surface side portion and impregnated in the gas diffusion layer, inside the one surface side portion and the one surface side impregnation portion A non-impregnated portion disposed above the outer portion, an outer portion disposed outside the protrusion, a filling portion disposed in the through hole, the other surface portion disposed on the other surface side of the protrusion, The other surface side impregnated portion disposed inside the other surface side portion and impregnated in the gas diffusion layer, and the non-impregnated portion disposed inside the other surface side portion and below the other surface side impregnated portion. It is characterized by having one .

  In the cell seal for a fuel cell of the present invention having the above-described configuration, the gasket is fixed to the gas diffusion layer by impregnating the outer periphery of the gas diffusion layer with a part of the molding material and passes through a part of the molding material. It is fixed to the electrolyte membrane by filling the holes. The through-hole is provided in the protruding part provided on the outer periphery of the electrolyte membrane in the membrane electrode assembly, and a gasket is integrally formed around the protruding part, so a part of the molding material is filled into the through-hole and solidified. Then, the anchor effect which suppresses that an electrolyte membrane displaces with respect to a gasket with the molding material solidified in the through hole and the through hole is exhibited. Therefore, the anchor effect suppresses the deformation of the electrolyte membrane and hence the membrane electrode assembly. On the other hand, since a part of the molding material of the gasket impregnates the outer peripheral portion of the gas diffusion layer, deformation of the gas diffusion layer can be suppressed. Therefore, from these, it is possible to suppress the occurrence of gaps and deviations due to deformation of the membrane electrode assembly and the gas diffusion layer.

  In the present invention, the protrusions are provided only on the electrolyte membrane constituting the membrane electrode assembly, and the protrusions are not provided on the electrode layers on both sides for the following reason.

  That is, since the projecting part is a part where the through hole is provided here, if the projecting part is provided not only in the electrolyte membrane but also in the electrode layer and the through hole is provided here, depending on the processing situation of the through hole, As a result, the electrode layers may enter, and as a result, the electrode layers on both sides of the electrolyte membrane may be short-circuited. When such a short-circuit occurs, the power generation function is impaired. Therefore, in order to ensure the separation of the double-sided electrode layers in order to prevent this short circuit, the present invention has a configuration in which no protruding portion for providing a through hole is provided in the electrode layer.

  The present invention has the following effects.

  That is, in the fuel cell cell seal of the present invention, the anchor effect is exhibited by the through-hole and the gasket molding material solidified in the through-hole as described above, and this anchor effect suppresses deformation of the electrolyte membrane and hence the membrane electrode assembly. It is possible. On the other hand, since a part of the molding material of the gasket impregnates the outer peripheral portion of the gas diffusion layer, it is possible to suppress deformation of the gas diffusion layer. Therefore, from these, it is possible to suppress the occurrence of gaps and deviations due to deformation of the membrane electrode assembly and the gas diffusion layer. Further, in the cell seal of the present invention, it is not necessary to perform a process of attaching a protective film in advance or a process of thermocompression bonding of the protective film and the gas diffusion layer in the manufacturing process, and the electrode layers on both surfaces of the electrolyte membrane are short-circuited. Nor. Therefore, as described above, according to the intended purpose of the present invention, it is possible to suppress the occurrence of gaps and deviations between the membrane electrode assembly and the gas diffusion layer with a relatively simple configuration. It is possible to provide a fuel cell cell seal capable of suppressing a decrease in efficiency.

  Next, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a cross section of a main part of a cell seal 1 for a fuel cell according to an embodiment of the present invention.

  The cell seal 1 according to this example is a membrane electrode composite in which electrode layers (also referred to as a porous catalyst electrode layer, a catalyst-attached electrode or a catalyst layer) 4 are respectively deposited on both surfaces of an electrolyte membrane (also referred to as an ion exchange membrane) 3. A gasket 6 made of a predetermined rubber-like elastic body is integrally formed on the outer peripheral portions of the (MEA) 2 and the gas diffusion layer (GDL) 5 bonded to both surfaces of the membrane electrode assembly 2. The separator (not shown) is sealed between the outer periphery of the electrolyte membrane 3 in the membrane electrode assembly 2 and the outer periphery of the electrode layer 4 and the gas diffusion layer 5 (left side in the figure). A protruding portion (also referred to as a protruding portion) 3a is provided, a through hole (also referred to as a through hole) 3b is provided in the protruding portion 3a, and the gasket 6 is integrally formed around the protruding portion 3a. The sket 6 is fixed to the gas diffusion layer 5 by impregnating the outer peripheral portion of the porous gas diffusion layer 5 with a part of the molding material, and the other part of the molding material fills the through hole 3b. By doing so, it is fixed to the electrolyte membrane 3.

  The protrusions 3a are provided on the entire outer periphery of the electrolyte membrane 3, and a plurality (a large number) of through holes 3b are provided at predetermined intervals in the circumferential direction.

  The gasket 6 includes a gasket body 6a having a substantially rectangular cross section fixed to the outer periphery of the membrane electrode assembly 2 and the gas diffusion layer 5, and a lip portion provided on both surfaces of the gasket body 6a and in close contact with the separator. 6b (also referred to as a seal portion) is integrally formed, and the former gasket body 6a is disposed on the one surface side portion 6c disposed on the one surface side of the protruding portion 3a, and is disposed on the inner side of the one surface side portion 6c for gas diffusion. The one-side impregnation portion 6d impregnated in the layer 5, the non-impregnation portion 6e disposed inside the one-surface side portion 6c and above the one-surface-side impregnation portion 6d, the outer portion 6f disposed outside the protruding portion 3a, and the through Filling part 6g arranged in the hole 3b, other side part 6h arranged on the other side of the protrusion 3a, other side impregnation impregnated in the gas diffusion layer 5 arranged inside the other side part 6h Part i, and an inner second surface side portion 6h is disposed below the other side impregnated portion 6i non-impregnated portion 6j has integrally.

  In addition, the electrode layer 4 of the membrane electrode assembly 2 is set to the same length as the gas diffusion layer 5 as shown in the figure, but it is sufficient that the electrode layer 4 does not reach the through hole 3b as described above. It may be set longer than 5. That is, the outer peripheral portion of the electrode layer 4 may protrude outward from the outer peripheral portion of the gas diffusion layer 5 as long as it does not reach the through hole 3b.

  In the fuel cell cell seal 1 having the above-described configuration, the gasket 6 is fixed to the gas diffusion layer 5 by impregnating the outer periphery of the gas diffusion layer 5 with a part of the molding material, and partially passes through the molding material. The electrolyte membrane 3 is fixed by filling the holes 3b. The through hole 3b is provided in a protruding portion 3a provided on the outer peripheral portion of the electrolyte membrane 3 in the membrane electrode assembly 2, and the gasket 6 is integrally formed around the protruding portion 3a. When the through-hole 3b is filled and solidified, the molding material solidified inside the through-hole 3b is engaged with the through-hole 3b, thereby suppressing the electrolyte membrane 3 from being displaced in the plane direction with respect to the gasket 6. An anchor effect is exhibited. Therefore, it is possible to suppress deformation (particularly contraction) of the electrolyte membrane 3 and thus the membrane electrode assembly 2 by this anchor effect. On the other hand, since part of the molding material of the gasket 6 is impregnated in the outer peripheral portion of the gas diffusion layer 5, it is possible to suppress deformation (particularly contraction) of the gas diffusion layer 5. Therefore, from these, it is possible to suppress the occurrence of a gap or deviation due to deformation (particularly contraction) in the membrane electrode assembly 2 or the gas diffusion layer 5.

  In addition, the cell seal 1 having the above-described structure is formed by inserting a laminated body composed of the membrane electrode assembly 2 and the gas diffusion layer 5 into a gasket molding die and integrally molding the gasket 6, There is no need to perform a process of attaching a protective film in advance as in the prior art or a process of thermocompression bonding of the protective film and the gas diffusion layer, and the manufacture thereof is easy.

  In addition, since no protruding portion is provided on the electrode layer 4 in the membrane electrode assembly 2 and the electrode layer 4 does not reach the through hole 3b, the electrode layers 4 on both surfaces of the electrolyte membrane 3 are not short-circuited.

  Therefore, from the above, it is possible to prevent the membrane electrode assembly 2 and the gas diffusion layer 5 from being deformed and causing gaps and deviations with a relatively simple configuration, thereby reducing the power generation efficiency of the fuel cell. It is possible to provide a cell seal 1 for a fuel cell that can suppress the above.

Sectional drawing of the principal part of the cell seal for fuel cells which concerns on the Example of this invention Sectional view of the main part of a cell seal for a fuel cell according to a conventional example Sectional drawing of the principal part of the cell seal for fuel cells according to another conventional example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cell seal 2 Membrane electrode assembly 3 Electrolyte membrane 3a Protrusion part 3b Through hole 4 Electrode layer 5 Gas diffusion layer 6 Gasket 6a Gasket body 6b Lip part 6c One side part 6d One side impregnation part 6e One side non-impregnation part 6f Outer part 6g Filling part 6h Other side part 6i Other side impregnation part 6j Other side non-impregnation part

Claims (1)

A pair of membrane electrode assembly (2) provided with electrode layers (4) on both sides of the electrolyte membrane (3) and a gas diffusion layer (5) stacked on both sides of the membrane electrode assembly (2) In the cell seal (1) for a fuel cell, in which the gasket (6) for sealing between the separators is fixed by integral molding,
Protruding portions (3a) protruding outward from the outer peripheral portions of the electrode layer (4) and the gas diffusion layer (5) are provided on the outer peripheral portion of the electrolyte membrane (3) in the membrane electrode assembly (2), A through hole (3b) is provided in the protrusion (3a), and the gasket (6) is integrally formed around the protrusion (3a).
The gasket (6) is fixed to the gas diffusion layer (5) by impregnating a part of the molding material into the outer periphery of the gas diffusion layer (5), and a part of the molding material is passed through the through-hole. It is fixed to the electrolyte membrane (3) by filling the hole (3b) ,
Further, the gasket (6) is disposed on the one surface side portion (6c) disposed on the one surface side of the protruding portion (3a) and on the inner side of the one surface side portion (6c) to impregnate the gas diffusion layer (5). The one surface side impregnation part (6d), the non-impregnation part (6e) disposed inside the one surface side part (6c) and above the one surface side impregnation part (6d), and the outside of the protrusion (3a) The outer part (6f) arranged in the through hole (3b), the filling part (6g) arranged in the through hole (3b), the other side part (6h) arranged on the other side of the protrusion (3a), The other surface side impregnation portion (6i) disposed inside the other surface side portion (6h) and impregnating the gas diffusion layer (5), and the other surface side portion (6h) inside and on the other surface side it has non-impregnated portion which is disposed below the impregnation site (6i) a (6j) integrally Cell seal for a fuel cell is characterized.

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