JP2001332276A - Gasket for fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize improvement in operating efficiency and a reliability of a fuel cell by protecting and safely sealing a collecting electrode frame, as to improving a sealing property and reducing a cost of the collecting electrode frame for a solid polymer type fuel cell. SOLUTION: The gasket for the fuel cell frame, mounted between the collecting electrode frame for the solid polymer type fuel cell, is provided, in which a base gasket 1 with a highly rigid elasticity is employed and to the upper and under sides of the base gasket, is arranged a gasket 2 with a lower hardness of 30 to 50 deg.. A form of the collecting electrode frame as well as improving the sealing property is achieved, to reduce the cost.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing material for a collector frame made of carbon constituting a polymer electrolyte fuel cell, and more specifically, to a fuel cell for protecting a collector frame and improving sealing performance. Gasket structure.

[0002]

2. Description of the Related Art In this type of fuel cell, a collector electrode frame for fixing an electrolyte membrane is formed of carbon.
A large number of the collector frames are arranged in a storage case in parallel with an appropriate interval, and the gap between the formed electrolyte membranes is passed through a liquid such as fuel gas or water, and a gasket is provided between the collector frames. The gasket is clamped on the gasket mounting flange of the collector frame as the mounting structure, but the gasket mounting flange is also formed of carbon similarly to the frame portion, so it has poor elasticity, It has the disadvantage that it is easily broken and unusable when it is loaded.

For this reason, when a synthetic rubber material or a synthetic resin material having a high hardness (for example, a product having a hardness of about 70 to 90 °) is used, the mounting flange is difficult to be broken due to a low spring constant. On the other hand, a mounting flange formed of carbon is used. The surface is not smooth and has an unsuitable surface roughness for sealing, so a gasket made of a synthetic rubber or synthetic resin with high hardness as described above does not have sufficient sealing power and can withstand use. Does not. In order to compensate for this drawback, it is necessary to employ a low-hardness synthetic rubber material having good conformability.

[0004]

The sealing material required for the above-mentioned problems is a sealing material having an intermediate hardness and adhesion that can satisfy a certain degree, if not all, of the required performance. It is conceivable to form a gasket from a material, but a gasket made of such a sealing material is, after all, a deception and neither requirement can be solved fundamentally. That is, if the hardness is set high, the mounting flange can be prevented from cracking with a low spring constant, but the sealing property is insufficient on a rough surface. Conversely, if the hardness is set low, it is difficult to guarantee the shape of the mounting flange.

An object of the present invention is to solve such drawbacks and to improve the operating efficiency and reliability of a fuel cell by securely fixing and sealing a collector frame.

[0006]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail with reference to the drawings. FIG. 1 shows a fuel cell gasket which is mounted between a plurality of collector frames constituting a polymer electrolyte fuel cell. As shown in the figure, a base gasket 1 is made of a high hardness elastic body made of synthetic rubber or synthetic resin and having a hardness of 70 to 90 °, and a low hardness of 30 to 50 ° made of synthetic rubber is applied to the compression surface of the base gasket 1. It is characterized in that the gasket 2 is arranged.

Further, in a carbon collector electrode frame constituting a fuel cell, there is provided a gasket for a fuel cell which is mounted between the plurality of collector electrode frames, and has a hardness of 90 to 100 ° as shown in FIG. A high hardness elastic body made of a hard synthetic resin material is used as a base gasket 11, an elastomer coating 3 made of an elastic body is applied to a compression surface of the base gasket 11, and a low hardness of 30 to 50 ° made of a synthetic rubber material is applied to the surface. It is characterized in that a hardness gasket 2 is arranged.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A gasket for a fuel cell according to the present invention for hermetically fixing a collector frame is mounted on a mating surface of the collector frame, and is sandwiched between the mating surfaces. The gasket for a fuel cell formed here is provided with a low hardness gasket 2 on a compression surface of a base gasket 1 made of a high hardness elastic body as shown in FIG.
Are formed in layers.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A fuel cell gasket having such a layer structure is provided to prevent cracking of a mounting flange by a low spring constant and to ensure sealing even on a rough surface. As the arrangement structure, various shapes can be adopted in order to provide the low hardness gasket 2 on the surface of the base gasket 1. For example, when the base gasket 1 is formed in a flat band shape, as shown in FIG. When the low hardness gasket 2 is provided on the surface (upper and lower surfaces in the drawing) in the shape of a projection, an effective arrangement structure capable of coping with local load and surface roughness is obtained. As the protruding strip shape, a semicircular shape as shown in FIG. 1, a chevron shape, a square shape, a trapezoidal shape, a wave shape, or a combination thereof are conceivable, and the shape is selected depending on a required situation and performance. .

Further, in order to improve the creep performance (the performance of the strain which changes with time caused in the solid due to the stress), the base gasket 11 is hardened to a hardness of 90 to 90%.
Hard synthetic resin material of about 100 ° (for example, polyester,
When formed of polycarbonate or engineered plastic material, the surface of the elastomer coating 3 is coated with an elastic elastomer (for example, the thickness of the base gasket 11 is 0.1 to 0.5 mm and the thickness of the elastomer coating 3 is 0.05. ~ 0.3mm
To the flange of the collector frame to deal with the cracks, and the low hardness gasket 2 of the compression surface ensures reliable sealing against the flat surface of the flange. Also, this base gasket 1 or 11
Is formed in the form of a thin film and is arranged, leaving sufficient flexibility despite its high hardness, exhibiting an effective elastic action together with the low hardness gasket 2 provided on the compression surface and exhibiting excellent sealing properties. Will do.

The base gasket 1 may be a molded gasket having a cross section of a round shape or a square shape in addition to the flat band shape as described above. What is necessary is just to form and form the low hardness gasket 2 on both sides of the compression. In the formation of the low-hardness gasket 2, in addition to the molding using a carved mold having a desired shape, for example, print molding using screen printing or a band-like material punched and formed from a plate-like material is used. Various methods such as bonding can be adopted. In the arrangement of the low hardness gasket 2, when it is provided in the form of a protrusion as shown in FIGS. 1 and 2, the base gasket 1 or 11 is basically located at a position where the compression gasket is turned away from each other. As shown in (2), if the base gasket 1 or 11 is provided so as to be displaced so as not to be opposed to each other on both sides of the base gasket 1 or 11, the point of compression force is misaligned, so that the elasticity of the base gasket 1 or 11 can be drawn out more. The structure is also advantageous for maintaining elasticity and deforming adhesion of the hardness gasket 2.

As the gasket material used here, rubber and thermoplastic elastomers / resins are suitable, for example, butyl rubber, styrene-butadiene copolymer, ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer , An ethylene-ethyl acrylate copolymer, butadiene rubber, silicone rubber, fluorine rubber, ethylene propylene rubber, or the like.

[0013]

According to the present invention, by combining and arranging the gasket materials having different hardnesses, it is possible to maintain the shape and improve the sealing performance of each of a large number of collector frames used in the fuel cell, thereby achieving cost reduction. That is, a synthetic rubber material or a synthetic resin material having a high hardness is excellent in creep characteristics, so that it is advantageous also in sealing properties, and also possesses excellent performance in insulating properties. The low-grade synthetic rubber material improves the conformability of the contact surface and complements the characteristics of the base gasket 1 having high hardness. With such a configuration, an accurate interval and a clear passage between the collector frames are maintained, and the passage of fuel gas, water, and the like is smoothed to maximize power generation efficiency.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view showing another embodiment of the present invention.

FIG. 3 is a cross-sectional view showing another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base gasket 11 Base gasket 2 Low hardness gasket 3 Elastomer coating

Claims (5)

[Claims] A fuel cell gasket mounted between said plurality of collector electrode frames in a carbon collector frame constituting a fuel cell, wherein said gasket has a hardness of 70 to 70 made of a synthetic rubber material or a synthetic resin material. A gasket for a fuel cell, characterized in that a 90 ° high hardness elastic body is used as a base gasket, and a low hardness gasket made of a synthetic rubber material and having a hardness of 30 to 50 ° is arranged on a compression surface of the base gasket. 2. A fuel cell gasket, which is mounted on a carbon collector frame constituting a fuel cell and is mounted between the plurality of collector frames, has a hardness of 90-1.
A high hardness elastic body made of a synthetic resin material of 00 ° was used as a base gasket, an elastomer coating was applied to a compression surface of the base gasket, and a low hardness gasket of a hardness of 30 to 50 ° made of a synthetic rubber material was disposed on the surface. A gasket for a fuel cell, comprising: 3. The gasket for a fuel cell according to claim 1, wherein the base gasket is formed as a thin film. 4. The gasket for a fuel cell according to claim 1, wherein the low-hardness gasket is arranged in a protruding strip shape on a compression surface of the base gasket. 5. The gasket for a fuel cell according to claim 1, wherein the low-strength gasket having a protruding strip shape is provided so as not to be opposed to a compression surface of the base gasket. Gasket for fuel cells.