JP4193015B2 - Gasket for fuel cell - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gasket for a fuel cell.
[0002]
[Prior art]
As shown in each of FIGS. 2 to 5, a cell 1 for a fuel cell includes a reaction electrode portion 2 in which a membrane-fixed reaction electrode 4 is fixed to an ion exchange membrane 3, and a collector electrode that is stacked on the reaction electrode portion 2. 5 and generating electric power by causing a chemical reaction by supplying hydrogen gas as a fuel.
[0003]
Conventionally, as a method of sealing between the reaction electrode part 2 and the collector electrode 5,
(1) As shown in FIG. 2, a type using a single rubber gasket 6 (refer to Japanese Patent Laid-Open Nos. 9-231987, 7-263004, 7-226220, or 7-153480),
(2) As shown in FIG. 3, a type in which a foamed sponge layer 9 is disposed on a rubber plate 8 and used as a gasket 7 (see Japanese Patent Laid-Open No. 7-31223),
(3) As shown in FIG. 4, a type using a gasket 10 integrally formed with the collector electrode 5, and
(4) As shown in FIG. 5, a type using a gasket 11 integrally formed with the ion exchange membrane 3 is known. However, these conventional techniques have the following disadvantages.
[0004]
That is, in any of the above prior arts, the gaskets 6, 7, 10, and 11 seal the gap between the reaction electrode portion 1 and the collector electrode 4, and the gaskets 6, 7, 10, and 11 are membrane-fixed reaction electrodes. The end face 4a is not sealed because it is away from the end face 4a. Therefore, there is a leakage of hydrogen gas in the direction of the end face 4a of the membrane-fixed reaction electrode 4, and this may cause the power generation efficiency of the fuel cell to decrease.
[0005]
[Problems to be solved by the invention]
In view of the above points, the present invention can seal the end face of the membrane-fixed reaction electrode of the fuel cell, thereby preventing hydrogen gas from leaking in the direction of the end face, thereby generating power for the fuel cell. An object of the present invention is to provide a fuel cell gasket capable of improving the efficiency.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, a gasket for a fuel cell according to claim 1 of the present invention comprises a reaction electrode portion in which membrane-immobilized reaction electrodes made of a porous material are respectively laminated on the upper and lower surfaces of an ion exchange membrane , and the reaction electrode portion . A gasket for a fuel cell that seals between collector electrodes that are stacked one above the other, and is integrated with each of the upper and lower surfaces of the ion exchange membrane, and is continuous with the end surface of the membrane-fixed reaction electrode and the end surface A covering portion that integrally covers a peripheral edge portion or a lower surface peripheral edge portion is integrally formed, and the thickness dimension of the covering portion extending above and below the reaction electrode portion is set to be larger than the thickness dimension of the reaction electrode portion. It is what.
Further, the fuel cell gasket according to claim 2 of the present invention is the fuel cell gasket according to claim 1, wherein the upper and lower gaskets are integrally formed with each other through a hole provided in the ion exchange membrane. It is characterized by.
[0007]
According to the gasket of the present invention having the above-described configuration, the gasket is molded so as to cover the end surface of the membrane-immobilized reaction electrode and the upper surface peripheral portion or the lower surface peripheral portion continuous to the end surface and seal the end surface. In addition, it is possible to prevent the hydrogen gas from leaking in the direction of the end face.
[0008]
The present invention has the following features.
[0009]
That is, the gasket of the present invention is formed by integrally molding rubber so as to cover the end face of the membrane-fixed reaction electrode as a seal between the collecting electrode and the reaction electrode part in order to solve the problems in the above-described conventional technology. In addition, the leakage of hydrogen gas from the end face of the membrane-fixed reaction electrode is eliminated, and the power generation efficiency corresponding to the supply loss can be improved.
[0010]
The gasket of the present invention is a gasket that seals between the collector electrode and the reaction electrode portion of the fuel cell, and has a porous reaction electrode on the end surface of the membrane-fixed reaction electrode in which the porous reaction electrode is laminated on both surfaces of the ion exchange membrane. A rubber having a convex shape for the purpose of sealing the electrode portion and the seal between the membrane-fixed reaction electrode and the separator, and the membrane-fixed reaction electrode is a porous carbon material. When the hydrogen gas to be supplied is supplied, the hydrogen gas passing through the ion exchange membrane and the membrane-immobilized reaction electrode is prevented from leaking from the end surface direction of the membrane-immobilized reaction electrode, thereby reducing the power generation efficiency.
[0011]
Furthermore, the gasket of the present invention seals between the end face of the membrane-fixed reaction electrode to seal between the collecting electrode and the reaction electrode portion, and prevents gas leakage from the end face of the membrane-fixed reaction electrode, thereby improving power generation efficiency. It is something to be made.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
[0013]
FIG. 1 shows an exploded cross section of a main part of a fuel cell 1 having a fuel cell gasket 21 according to an embodiment of the present invention.
[0014]
The fuel battery cell 1 includes a reaction electrode unit 2 in which membrane-fixed reaction electrodes (also referred to as porous reaction electrodes) 4 are stacked on both upper and lower surfaces of an ion exchange membrane 3, and a collection that is stacked above and below the reaction electrode unit 2. An electrode (also referred to as a separator) 5 generates a chemical reaction by supplying hydrogen gas as a fuel, and the cell 1 includes a gasket 21 having the following configuration. It has been.
[0015]
That is, the gasket 21 is formed into a lip shape having a convex cross section by a predetermined rubber material, and is integrated with the upper and lower surfaces of the ion exchange membrane 3 at the same time as the vulcanization molding. When 2 and the collector electrode 5 are overlapped with each other, the pressure between the two and the five is compressed and the gap between the two and the five is sealed. Further, the gasket 21 has an end face 4a of the membrane-fixed reaction electrode 4 and an upper surface peripheral edge 4b or a lower surface peripheral edge 4c of the electrode 4 continuous with the end face 4a (both 4b and 4c are collectively referred to as a flat peripheral edge). The covering portion 22 is integrally formed, and the covering portion 22 covers the end surface 4a and the upper surface peripheral portion 4b or the lower surface peripheral portion 4c of the electrode 4 to seal them. Further, as shown in the drawing, the thickness dimension w1 of the covering portion 22 extending above and below the reaction electrode section 2 is set larger than the thickness dimension w2 of the reaction electrode section 2.
[0016]
Therefore, according to the gasket 21 according to this embodiment, the end surface portion (porous surface) composed of the end surface 4a and the upper surface peripheral portion 4b or the lower surface peripheral portion 4c of the membrane-fixed reaction electrode 4 by the covering portion 22 formed integrally with the gasket 21. The end surface portion can be sealed by covering the reaction electrode portion), thereby preventing leakage of hydrogen gas in the direction of the end surface 4a, thereby improving the power generation efficiency of the fuel cell. be able to.
[0017]
When the gasket 21 is manufactured, a hole having a size larger than the inlet (in the ion exchange membrane 3 at a location corresponding to the inlet for injecting rubber in a mold (not shown) for molding the gasket 21). It is preferable that the gaskets 21 on both the upper and lower surfaces of the ion exchange membrane 3 are integrally formed through the holes. In this case, the diameter of the rubber injection port of the mold is preferably 0.3 to 2 mm, more preferably 0.5 to 1.5 mm. The diameter of the hole formed in the ion exchange membrane 3 is In the case where the diameter is 0.5 mm, it is preferable that the diameter is 0.7 mm or more and about 2 mm (if the diameter is larger than this, the size of the ion exchange membrane 3 is increased, so that the cell 1 is reduced in size and cost). Is not preferable in terms of chemical conversion.
[0018]
【The invention's effect】
The present invention has the following effects.
[0019]
That is, in the gasket for a fuel cell of the present invention having the above-described configuration, the gasket is formed so as to cover the end face of the membrane-fixed reaction electrode of the fuel cell and seal the end face. This can prevent the leakage of hydrogen gas and improve the power generation efficiency of the fuel cell.
[Brief description of the drawings]
FIG. 1 is an exploded cross-sectional view of a main part of a fuel cell equipped with a gasket for a fuel cell according to an embodiment of the present invention. FIG. 2 is an exploded cross-sectional view of a main part of a fuel cell equipped with a gasket for a fuel cell according to a conventional example. FIG. 3 is an exploded cross-sectional view of a main part of a fuel cell having a fuel cell gasket according to another conventional example. FIG. 4 is a main part of a fuel cell having a fuel cell gasket according to another conventional example. FIG. 5 is an exploded sectional view of a main part of a fuel cell provided with a gasket for a fuel cell according to another conventional example.
DESCRIPTION OF SYMBOLS 1 Fuel cell 2 Reaction electrode part 3 Ion exchange membrane 4 Membrane fixed reaction electrode 4a End surface 4b Upper surface peripheral part 4c Lower surface peripheral part 5 Collecting electrode 21 Gasket 22 for fuel cells Covering part

Claims (2)

Upper and lower surfaces each of which is made of a porous membrane fixed reaction electrode (4) reacting the electrode unit formed by laminating and (2), the reaction electrode portion (2) respectively vertically superposed are collector electrodes of the ion-exchange membrane (3) ( 5) a fuel cell gasket (21) for sealing between
The ion exchange membrane (3) is integrated with each of the upper and lower surfaces,
The membrane-fixed reaction electrode (4) has an end surface (4a) and a covering portion (22) covering the upper surface peripheral portion (4b) or the lower surface peripheral portion (4c) continuous with the end surface (4a),
A thickness dimension (w1) of the covering part (22) extending above and below the reaction electrode part (2) is set larger than a thickness dimension (w2) of the reaction electrode part (2). Gasket for fuel cell. The fuel cell gasket according to claim 1,
The gasket for a fuel cell, wherein the upper and lower gaskets (21) are integrally formed with each other through a hole provided in the ion exchange membrane (3).

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