JPS61216254A - Fuel cell - Google Patents

Abstract

PURPOSE:To improve sealing characteristic by providing a sealing member to the part opposing to the gasket of the gas diffusion electrode and converting two sides of electrode end portions parallel to the gas flow direction of gas diffusion electrode with the U-shaped sealing material. CONSTITUTION:A sealing member 12 is provided to the part opposing to the gasket 7 of the gas diffusion electrodes 1, 2, the four corners of electrode substrates 1a, 2a opposed to the gasket 7 of manihold 8 are cut away and the sealing member 12 formed to the shape of such cut-away part is arranged through a bonding layer 14 having elasticity. The two sides of electrode end portion 10 parallel to the gas flow direction of electrode substrates 1a, 2a are covered with the U-shaped sealing material 13. Thereby, reliability and regidity are enhanced and the sealing characteristic between the cell body and manihold 8 can be improved.

Description

[Detailed description of the invention] [Field of application of the invention] The present invention relates to fuel cells.

[Background of the invention]

7 to 10- show conventional examples of fuel cells. As shown in the figure, the fuel cell consists of a fuel electrode 1, which is a gas diffusion electrode, an oxidizer electrode 2, and these 'm&1.
A battery body 6 is formed by stacking a plurality of unit batteries 4 having an electrolyte layer 3 disposed between them with a separator 5 interposed therebetween. It is composed of a manifold 8 for supplying and discharging fuel gas P and oxidant gas Q'li, respectively, to and from the agent electrode 2 as indicated by arrows in the figure (see FIGS. 7 and 8).

The fuel electrode 1 is composed of an electrode substrate 1a and a catalyst layer 1b, and the oxidizer electrode 2 is composed of an electrode substrate 2a and a catalyst layer 2b.

Fuel gas P1 and oxidizing gas Q are respectively distributed through 2a (
(See Figure 9).

In the fuel cell configured in this way, the electrode substrates la, 2a
This is shown using fuel electrode 1 as an example because it is porous (
As shown in Figure 9), gas leaks from the gas flow path 9 to the outside of the fuel electrode 1 through the substrate end 10 of the electrode substrate 1a as indicated by the broken line in the figure, causing gas to leak from the manifold. 8
The oxidant gas Q and the fuel gas P will mix inside the tank, which is not desirable in terms of operation. Therefore, a seal is required to prevent gas leakage at the electrode end portion 10 of the electrode substrate 1a. The same applies to the oxidizer electrode 2.

Also, the battery body 6 has a gasket 7 due to dimensional tolerances during battery manufacturing and tolerances due to battery stacking work.
Irregularities occur on the main surface of the battery body 6 and the manifold 8.
There is a possibility that a gap 11 may be generated between the two. As a result, gas leakage occurred from the gap 11, which not only made it impossible to control the operating pressure properly, but also posed the risk of explosion due to the mixture of hydrogen, which is the fuel gas, and oxygen, which is the oxidizing gas.
(See Figure 10).

The electrode end portions 10 of the IE substrates 1a, 2a may be sealed by impregnating the electrode end portions 10 with fluororubber dispersed in a dispersion liquid, or by adjusting the pore diameter of the electrode end portions 10 to the electrode substrates 1a, 2a.
There are some that are made smaller than the other parts of a to hold the electrolyte and are used as wet seals. However, among these, the former one in which the electrode end 10 was impregnated with fluororubber lacked airtightness because the pores in the electrode end 10 could not be sufficiently closed. The latter type of wet seal lacks reliability and durability because the electrolyte moves due to differential pressure and capillary action, and decreases due to evaporation. In addition, as a seal between the manifold 8 and the battery body 6, a grease-like sealing material was applied to the uneven portions of the surface in contact with the gasket 7, but it was not as reliable as the electrode end portions 10 of the electrode substrates 1a and 2a described above. It lacked strength and durability. In addition, as related to these, for example, Japanese Patent Application Laid-Open No.
There are No. 747 and Japanese Unexamined Patent Publication No. 58-152077.

[Purpose of the invention]

The present invention has been made in view of the above points, and provides a fuel cell having a seal at the end of an electrode that is highly reliable and durable, and enables improved sealing performance between the battery body and the manifold. The purpose is to

[Summary of the invention]

That is, the present invention includes a battery main body in which a plurality of unit batteries are stacked with separators interposed therebetween, and a manifold arranged on the side surface of the battery main body for supplying and discharging gas to the battery main body. a pair of gas diffusion electrodes having a channel, a matrix disposed between the gas diffusion electrodes and holding an electrolyte, and the cell main body and the manifold being sealed with a gasket; A sealing member is provided at a portion of the gas diffusion electrode facing the gasket, and two sides of the electrode end portion parallel to the gas flow direction of the gas diffusion electrode are gripped with a U-shaped sealing material. As a result, a sealing member is provided at the gasket-opposing part of the gas diffusion electrode, and the two sides of the electrode end parallel to the gas flow direction of the gas diffusion electrode are treated with a U-shaped sealing material. .

[Embodiments of the invention]

The present invention will be explained below based on the illustrated embodiments. An embodiment of the present invention is shown in FIGS. 1-4.

Note that the same parts as in the prior art have been given the same reference numerals, so their explanations will be omitted. In this embodiment, a sealing member 12 is provided at the part of the gas diffusion electrode 1.2 facing the gasket 7, and the gas distribution of the gas diffusion electrode 1.2 is Two sides of the electrode end 10 parallel to the direction were covered with a U-shaped sealing material 13. By doing this, the sealing member 12 is provided at the part of the gas diffusion electrode 1.2 facing the gasket 7, and the two sides of the electrode end 10 parallel to the gas flow direction of the gas diffusion electrode 1.2 are The battery body and manifold 8 are covered with a letter-shaped sealing material 13 for high reliability and durability.
It is possible to obtain a fuel cell having a seal at the electrode end portion 10 that enables improved sealing performance between the electrode end portion 10 and the electrode end portion 10.

That is, the sealing member 12 is provided at the part of the gas diffusion electrode 1.2 facing the gasket 7, but the four corners of the electrode substrates 1a and 2a facing the gasket 7 of the manifold 8 are cut out, and the seal is formed into the shape of the notch. The parts 12 were arranged with an adhesive layer 14 having elasticity interposed therebetween. and electrode substrate 1a
, 2a, the two sides of the electrode end 10 parallel to the gas flow direction are covered with a U-shaped (D'/-) material 13. As this sealing member 12, a fluororesin material with excellent heat resistance and acid resistance, For example, polytetrafluoroethylene (hereinafter referred to as PTF)
PF'A) or tetrafluoroethylene snow perfluoroalkyl vinyl ether copolymer (hereinafter referred to as PF'A)
) etc. are used. Adhesive layer 1 having elasticity
As No. 4, a fluororubber-based adhesive is used. In this embodiment, an adhesive layer 14 having elasticity is arranged between the sealing member 12 and the electrode substrates 1a and 2a, but the sealing member 12
The material may be made of a material having good elasticity, such as fluororubber, and may be placed in the notch. U-shaped sealing material 1
As material 3, a fluororesin material having excellent heat resistance and acid resistance, such as a film material of PTFE4 or PF'A, or a film material of animide resin is used. This U-shaped sealing material 13 and the electrode end portion 10 including the sealing part 12 of the electrode substrates 1a and 2a may be bonded.

To refill, do the following: Using a combination of, for example, PTFE or polyimide film, which is melted and fluidized by heating, and which is not melted and fluidized by heating, the material is arranged so that the material to be melted and fluidized faces the electrode end 10, and then heated. Seal or PTIi”E
1 lum is hardened and glued with polyimide-based adhesive.

By doing this, gas leaks passing through the electrode ends 10 of the electrode substrates 1a and 2a, indicated by broken lines in FIG. 9, are sealed by the continuous U-shaped sealing material 13. , no longer affected by differential pressure,
A gas seal at the electrode end 10 with excellent reliability and durability can be obtained. Furthermore, since the portion of the electrode end portion 10 facing the gasket 7 has elasticity, among the unevenness of the laminated surface shown in FIG.
As shown in the figure, the absorption is made possible by the deformation of the elastic part. Although FIG. 3 shows a case where the elastic sealing member 12 is arranged in the notch, it is also possible to arrange an elastic adhesive layer 14 between the electrode end 10 and the sealing member 12 as described above. Even when provided, similar effects can be obtained, and a gas seal structure of the electrode end portion 10 suitable for gas sealing between the battery main body and the manifold 8 can be obtained.

In this embodiment, as shown in FIG. 4, it is also possible to make the U-shaped surface of the electrode end 10 in contact with the sealing material 13 thinner to make the thickness uniform after the sealing process. .

Another embodiment of the invention is shown in FIGS. 5 and 6. In this embodiment, the sealing members 12a arranged at the four corners of the electrode substrates 1a and 2a are arranged on the electrode substrate 1a.

It was molded to be longer in the gas flow path direction than the outer shape of 2a.

After lamination, the protruding parts were sequentially bent downward as indicated by the arrows in the figure to form a manifold sealing surface. By doing this, all the irregularities on the laminated surface shown in FIG. 10 described above can be absorbed by bending the protrusion. In this case, if the sealing member 12a is made of an elastic material such as fluororubber, the effect will be greater.

On the other hand, if the sealing member 12a is made of thermoplastic resin without elasticity such as heat-resistant and acid-resistant PFA, it is also possible to form a manifold sealing surface by heating and melting the protruding parts after lamination. It is.

In this way, the electrode substrate 1a in each of the above embodiments.

The electrode end 10 of 2a is covered with a continuous film, and by using a gas-impermeable film of about 25 μm, a sealing structure with excellent reliability and durability is obtained, and the manifold shield sealing surface is elastic. Since the manifold seal structure is made of a certain material, it is possible to obtain a manifold seal structure that can absorb the unevenness of the Mk layer.

Note that in each of the above embodiments, the electrode substrate 1a.

The shape of the notch provided in 2a is not limited to the L-shape as shown in the figure, but may be any shape such as a square or a rectangle.

＜It became possible to obtain a seal at the end of the electrode that made it possible to improve the sealing performance between the battery body and the manifold.
It is possible to obtain a fuel cell that has high reliability and durability, and has a seal at the end of the electrode that enables improved sealing performance between the cell body and the manifold.

[Brief explanation of drawings]

Figure 1 shows an electrode group of an embodiment of the fuel cell of the present invention! FIG. 2 is a front view of the electrode substrate according to one embodiment, FIG. 3 is a partial cross-sectional view of the electrode substrate according to one embodiment, and FIG. 4 is a partial sectional view of the electrode substrate according to one embodiment. Front view of the board,
FIG. 5 is a partial sectional view of the plane of the electrode substrate of another embodiment of the fuel cell of the present invention, the sixth factor is an enlarged view of the main parts of the stacked battery of another embodiment, and FIG. 7 is a diagram of the conventional fuel cell. FIG. 8 is a partial cross-section lf+10 of a conventional fuel cell, FIG. 9 is a vertical sectional side view of an electrode end of a conventional fuel cell, and FIG. 10 is a 911 side view of a conventional fuel cell. DESCRIPTION OF SYMBOLS 1... Fuel electrode (gas diffusion electrode), 1a... Electrode substrate, 2... is a chemical agent electrode (gas diffusion 1 pole), 2a... Electrode substrate, 3... Electrolyte layer, 4 ...Unit battery, 5...
・Separator, 6... Battery body, 7... Gasket, 8... Manifold, 9... Gas flow path, 10...
・Electrode end (end of electrode substrate), 11... air gap, 12
, 128... Seal member, 1-3... U-shaped sealing material, 14... Adhesive layer.

Claims (1)

[Claims] 1. A battery body comprising a plurality of unit batteries stacked together with separators interposed therebetween, and a manifold disposed on a side surface of the battery body for supplying and discharging gas to and from the battery body; In a fuel cell, the battery has a pair of gas diffusion electrodes having a gas flow path, a matrix disposed between these gas diffusion electrodes and holding an electrolyte, and the battery body and the manifold are sealed with a gasket, A fuel characterized in that a sealing member is provided at a portion of the gas diffusion electrode facing the gasket, and two sides of the end of the electrode parallel to the gas flow direction of the gas diffusion electrode are covered with a U-shaped sealing material. battery. 2. The sealing member is disposed in notches provided at four corners of the gasket-facing portion of the gas diffusion electrode, and has elasticity formed into the shape of the notch. The fuel cell according to item 1. The fuel cell according to claim 1, wherein the fuel cell is disposed in notches provided at four corners of the gasket facing portion via an adhesive layer having elasticity, and is molded in the shape of the notches. . 4. Claim 1, wherein the U-shaped sealing material is hermetically bonded to two sides of the electrode end portion parallel to the gas flow direction of the gas diffusion electrode including the sealing member.
Fuel cell as described in Section.