JP2004055276A - Gasket for fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the fixability and sealability of a plurality of collector electrode frames at a low cost in a gasket for the collector electrode frames formed of carbon for constituting a solid polymer type fuel cell. <P>SOLUTION: A step 11 is formed on the end face of the collector electrode frame 1, and an annular gasket 2 having a protruding strip 21 on the step 11 is heat press bonded by a thermosetting adhesive 3. Thus, the gasket can be simply and surely mounted at the collector electrode frame and completely sealed to enhance the operating efficiency and reliability of the fuel cell. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gasket for a collector electrode frame formed of carbon constituting a polymer electrolyte fuel cell, and more specifically, a fuel cell that achieves a plurality of collector electrode frames with improved fixability, sealing performance, and cost reduction. Relates to gaskets.
[0002]
[Prior art]
This type of fuel cell has a structure in which a large number of collector electrode frames made of carbon are arranged in a row with appropriate intervals in a case, and a liquid such as fuel gas or water passes through the gap. As a sealing structure between them, a groove is formed on one mating surface of the collector electrode frame, and a band-like or O-ring gasket is mounted in the groove, and the other mating surface is tightened to seal the structure. A gasket made of an elastic material is directly printed on the mating surface, and the other mating surface is tightly sealed to form a seal, or the mating surface of the collector electrode frame is the simplest structure. As a general sealing method, a sheet-like gasket is sandwiched between the two so as to achieve sealing.
[0003]
[Problems to be solved by the invention]
However, in a sealing structure in which a groove is formed on the mating surface of the collector electrode frame and a belt-shaped or O-ring gasket is attached thereto, the belt-shaped or O-ring gasket must be incorporated along the groove. In addition, the assembly work is difficult and takes a lot of time, and it is an uncertain sealing structure with many downsides that is prone to mounting defects such as misalignment and floating, so it is impossible to reduce manufacturing cost by all means have. Furthermore, if a tightening pressure exceeding a specified level is applied to the band-shaped or O-ring-shaped gasket placed in the groove, it is difficult to absorb deformation in the groove, and in the worst case, the collector electrode frame may be destroyed.
In addition, the sealing structure in which the gasket is directly printed on the mating surface is printed by using a silk screen printing technique, so the gasket material and the shaping shape are limited, and this is applicable. The gasket material and the gasket shape generally have problems in sealing performance and durability, and do not provide a stable sealing force.
In a simple structure in which the sheet-like gasket is sandwiched between the mating surfaces, the mounting position is easy to shift because there are few parts for engaging and fixing the sheet-like gasket, and the mating surface of the collector electrode frame is bent. This displacement is unacceptable because of its low absorption capacity, and if it breaks or bites, the mating surfaces may be damaged or even destroyed.
[0004]
An object of the present invention is to solve such drawbacks and to increase the operating efficiency and reliability of a fuel cell by allowing a gasket to be easily and securely attached to a collector electrode frame and completely sealing it.
[0005]
[Means for Solving the Problems]
The present invention will be described in detail with reference to the drawings. As shown in FIG. 1, when a plurality of collecting electrode frames 1 which are constituent members of a polymer electrolyte fuel cell are arranged in a row at appropriate intervals in a case, A stepped portion 11 is formed on the end face of the collector electrode frame 1, and an annular gasket 2 made of synthetic rubber having a thickness of 0.1 to 1.0 mm and a ridge 21 in a shape along the stepped portion 11 is formed, and the stepped portion is formed. The thermosetting adhesive 3 is applied and formed on the sealing surface of the portion 11, and the annular gasket 2 is bonded by heating and pressure through this to complete the fuel cell gasket.
[0006]
Further, the thermosetting adhesive 3 used in the above is characterized by comprising either a two-component epoxy resin adhesive or a silicone-based adhesive.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The annular gasket 2 according to the present invention is attached to the step portion 11 on the end face of the collector electrode frame 1 as described above, and is firmly fixed and integrated by the thermosetting adhesive 3.
The collector electrode frame 1 constituting the fuel cell used here is made of gas-impermeable carbon which is made gas impermeable by compressing carbon, and is composed of an electrolyte membrane, two electrodes, and two collector electrodes. A partition is formed when the unit cells are stacked in the thickness direction. For this reason, it is necessary to seal the gas-impermeable carbon with insufficient smoothness on the surface thereof without fail for a long period of time, and the thermosetting adhesion to the annular gasket 2 having a thickness of 0.1 to 1.0 mm and the ridges 21 formed thereon. Thermocompression bonding with the agent 3 is an important point.
[0008]
【Example】
In such a molding of a gasket for a fuel cell according to the present invention, an example is shown. The collector frame 1 on which carbon is compression-formed is immersed in a cleaning liquid such as ethanol or toluene for over about 10 minutes. Let sonic wash. A two-component epoxy resin adhesive is applied to the step portion 11 on the end face of the collector electrode frame 1, and then fluorinated rubber is vulcanized for 2 to 3 minutes at 170 to 185 ° C. using a mold. The caulking annular gasket 2 is molded (not shown), and the annular gasket 2 is placed on the applied epoxy resin adhesive, and the mold 4a, 4b as shown in FIG. These are integrated by heating and pressure bonding for 5 to 20 minutes.
[0009]
Various structures can be selected for the annular gasket 2 here. As shown in FIG. 1, the annular gasket 2 needs to have a thickness that protrudes beyond the sealing surface of the collector electrode frame 1, and has a protrusion 21 with a thickness of 0.1 to 1.0 mm. Shape is preferred.
As the ridge 21, a mountain-shaped protrusion having both hems as shown in FIG. 1, a one-side protrusion protruding to one side as shown in FIG. 2, or a plurality of protrusions forming a plurality of protrusions (not shown). Select according to the required situation.
What is important here is that the annular gasket 2 is attached to the stepped portion 11 on the end face of the collector frame 1, where the annular gasket 2 is deformed due to tightening compression from the opposing member. As a result, the excessively deformed portion is brought into close contact with the mating member and moved to the outer portion of the step portion 11, and as a result, stress relaxation of the synthetic rubber can be prevented and appropriate adhesion can be maintained at all times.
[0010]
The fuel cell gasket according to the present invention prevents deformation of the stepped portion 11 of the collector electrode frame 1 where sufficient strength cannot be secured due to a low spring constant, and also ensures sufficient sealing performance even on a rough seal surface of carbon. It has become a thing.
[0011]
Here, by attaching the annular gasket 2 to the end face of the collector frame 1, the mounting workability is dramatically improved and secure fixing without deviation is achieved, and the ratio related to the reduction of the manufacturing cost is extremely large. Become.
[0012]
Examples of the molding material for the annular gasket 2 used here include rubber materials and thermosetting elastomers / resin materials. For example, rubber materials include butyl rubber, styrene-butadiene copolymer, Ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, butadiene rubber, nitrile rubber, hydrogenated nitrile rubber, acrylic rubber, silicone rubber, fluorine rubber, fluorosilicone rubber, Perfluoroalkyl ether rubber, ethylene propylene rubber or the like can be used.
[0013]
【The invention's effect】
According to the present invention, it is possible to improve the sealing performance and reduce the cost of each collector electrode frame 1 used in many fuel cells.
That is, since the annular gasket 2 is formed on the stepped portion 11 on the end face of the collector electrode frame 1, the assembly to the collector electrode frame 1 does not take time and the mounting safety is high and reliable. Reduce costs.
Further, the annular gasket 2 is bonded and integrated through the thermosetting adhesive 3 so that the rough surface of the carbon surface is cleanly filled to form a smooth surface, and the sealing performance of the annular gasket 2 is supported from the base surface.
In addition to being surely fixed without displacement, the compressive stress of the annular gasket 2 is maintained by the relief action of excessive deformation, and a strong sealing force is exerted to provide a stable sealing force.
With such a configuration, an accurate interval and a clear passage between the collector electrode frames 1 are maintained, and the passage of fuel gas, water, etc. is smoothed to maximize the power generation efficiency.
[Brief description of the drawings]
【The invention's effect】
FIG. 1 is a cross-sectional view showing an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing another embodiment of the present invention.
FIG. 3 is a cross-sectional view showing an adhesive state of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Collector electrode frame 11 Step part 2 Annular gasket 21 Projection 3 Thermosetting adhesive

Claims (3)

A collector cell frame formed of carbon constituting a fuel cell, a gasket for a fuel cell attached between a plurality of collector electrode frames maintaining a gap,
Forming a stepped portion on the end face of the collector electrode frame;
An annular gasket having a ridge with a thickness of 0.1 to 1.0 mm along the stepped portion is formed,
A fuel cell gasket, wherein an annular gasket is heated and pressure-bonded to a sealing surface of the stepped portion via a thermosetting adhesive. 2. The fuel cell gasket according to claim 1, wherein the thermosetting adhesive is a two-component epoxy resin adhesive. 2. The fuel cell gasket according to claim 1, wherein the thermosetting adhesive is a silicone-based adhesive.

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