JPS6273576A - Fuel cell - Google Patents

Abstract

PURPOSE:To shut off the adverse effect with an insulating layer even when a different gas is leaked into a gas passage in the vicinity of the end of electrode from the end of electrode by arranging an insulating layer which covers the end of electrode parallel to a gas passage and covers the bottom of the gas passage in the vicinity of the end of electrode at the end of electrode. CONSTITUTION:An insulating layer which covers the end parallel to a gas passage 2a0 and covers the bottom of the gas passage 2a0 in the vicinity of an electrode end part 2a1 is arranged at the end (electrode end) 2a1 of at least one electrode 2a of electrodes 2a, 2b. The insulating layer is formed with a resin film 4. Even when a different gas is leaked into the gas passage 2a0 in the vicinity of the electrode end 2a1 from the electrode end 2a1, its averse effect is shut off by the resin film 4. Decrease in cell performance and deterioration in electrode caused by leaked gas can be prevented.

Description

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

[Background of the invention]

Conventionally, a technique for sealing the electrode end to prevent the mixing of fuel gas and oxidizing gas due to gas leakage at the electrode end of a fuel cell, that is, the mixing of different gases, was disclosed in Japanese Patent Laid-Open No. 58.
-44672 publication, JP-A-59-68171 publication,
JP-A-59-46767, JP-A-60-1056
Publication No. 4, JP-A-60-10565, JP-A-59
JP-A-205164, JP-A-59-207-563, JP-A-60-66, etc.

Among these, for example, JP-A-59-207563-% is effective against gas leakage penetrating the electrode end, but
To prevent gas leakage through the interface between the electrode end and the separator, separate measures are required if the electrode surface is not sufficiently smooth. In addition, for example, Japanese Patent Application Laid-Open No. 60-10564 and No. 60-10565 are effective against both gas leakage penetrating through the electrode end and gas leakage through the interface between the electrode end and the separator. However, the shape of the separator becomes complicated.

[Purpose of the invention]

The present invention has been made in view of the above points, and an object of the present invention is to provide a fuel cell that can prevent cell performance and cell deterioration from being adversely affected even if a foreign gas leaks from the electrode end. The purpose is to

[Summary of the invention]

That is, the present invention provides a fuel cell comprising a pair of gas diffusion electrodes that are arranged opposite to each other with an electrolyte matrix in between and have a gas flow path, and a separator laminated on the gas diffusion electrodes. An insulating layer is provided at an end of one electrode to cover an end parallel to the gas flow path, and an insulating layer is provided at the end of the electrode to cover an end parallel to the gas flow path. As a result, even if a foreign gas leaks from the electrode end to the electrode end and into the gas flow path, the insulating layer blocks the influence.

[Embodiments of the Invention] The present invention will be described below based on illustrated embodiments. FIG. 1 shows an embodiment of the invention. As shown in the figure, the fuel cells are arranged facing each other with an electrolyte matrix 1 in between, and gas flow channels 2. A pair of gas diffusion electrodes (hereinafter referred to as electrodes) 2a, 2b having ao
Separator 3 laminated on these gas diffusion electrodes 2a, 2b
+i, 3b, etc. In the fuel cell configured as described above, in this embodiment, at least one of the electrodes 2a and 2b is covered with an end parallel to the gas flow path 2ao at the end 2a1 of one of the electrodes 2a, and Electrode end 2. 'll was provided with an insulating layer covering the end parallel to the gas flow path 2ao. This insulating layer was then formed of a resin film 4.

By doing this, the end 2ai of at least one of the electrodes 2a, 2b is covered with the end parallel to the gas flow path 2ao, and the gas flow path 2a is covered with the electrode end 2ax.
Since the resin film 4 covering the end parallel to the ao is thrown, even if foreign gas leaks from the electrode end 2ar to the electrode end 2ax and into the gas flow path 2ao, the resin film 4 will prevent it. This influence can be blocked, and a fuel cell can be obtained in which even if a foreign gas leaks from the electrode end 281, it will not have an adverse effect on battery performance and battery deterioration.

That is, the resin film 4 is provided on the electrode end 2az, and the resin film 4 is placed on the electrode end 2a1 so that the width on the electrode 28 surface on the electrolyte matrix 1 side is wider than the separator 3a side by the width of the gas flow path 2ao. It was made large enough to cover the electrode end 2az and the lower part of the gas flow path 2ao. By doing so, it is possible to prevent the battery performance and battery deterioration from being adversely affected even if a foreign gas leaks from the electrode end 2as.6 In other words, the electrode end 2ai is covered with a resin film or the like. By covering and providing an end seal, it is possible to prevent foreign gas from penetrating the porous electrode end 2nx, but leakage of foreign gas from the interface between the separator 3a and the electrode end 2ax is prevented. There is a possibility that the problem cannot be prevented due to minute irregularities in the thickness of the electrode end 2a1, the separator 3a, and the end seal.

By the way, such leakage of different gases occurs at the electrode end 2a.
It is experimentally known that it is maximum at the first gas flow path 2ao from X, and rapidly decreases exponentially from the second line onward. Therefore, as in this embodiment, the resin film 4 is attached to the electrode end 2F1.
1 to the end parallel to the gas flow path 2ao on the electrode end 2a+ side, the separator 3a and the electrode end 2ax
This prevents short-circuiting of the normal power generation section due to foreign gas leaking from the interface with the electrode 2a, preventing short-circuit current from flowing, and preventing damage to the electrode 2a section. It can prevent the harmful effects of leaking gas. In other words, in the electrode part where different gases are mixed, due to the lack of reactive gas, the electrochemical electrode reaction does not occur slowly, the effective power generation area decreases, the battery voltage decreases, and the non-power generation part caused by the lack of reactive gas. will short-circuit the normal power generating part, and a short circuit current will flow to the non-generating part, and this short circuit current will be 1! This will damage the t42 a section. However, as mentioned above, a lot of foreign gas leaks in! Due to the resin 111a4 covering the end parallel to the gas flow path 2ao at the extreme portion 2ax, the normal power generation portion is not short-circuited, and therefore no short-circuit current flows.

FIG. 2 shows another embodiment of the invention.

In this example, the insulating layer is formed of a resin film 4a and an insulating film 5. Then, the resin film 4a covered the electrode end 2ai, and the insulating layer 5 covered the electrode end 2a1 and the end parallel to the gas flow path 2ao. By doing so, the gas flow path 2a is formed at the electrode end 2ai.

The bottom part is covered with the insulating film 5, and the same effect as in the above case can be achieved.

That is, an absolute layer 5 having a width extending from the electrode end 2at to the electrode end 2ax to the inside of the gas flow path 2ao was inserted between the pair of electrodes 2a and 2b.

In this case, the width of the resin 1jJ4a can be formed to be the same width as the side facing the separator 3a, for example, as shown in the figure.

In addition, in each of the above embodiments, by expanding the insulating layer on the electrolyte matrix 1 side to the inside of the processing range of the gas flow w42ao, the effective electrode area may be reduced;
A gas flow path 2a is provided at the electrode end portion 2a1.

By performing additional processing, the configuration of each embodiment can be realized without reducing the effective electrode area.

〔Effect of the invention〕

As mentioned above, the present invention prevents the battery performance and battery deterioration from being adversely affected even if a foreign gas leaks from the electrode end. It is possible to obtain a fuel cell in which deterioration is not adversely affected.

[Brief explanation of drawings]

FIGS. 1 and 2 are longitudinal sectional views around the electrode ends of a pair of gas diffusion electrodes showing different embodiments of the fuel cell of the present invention. DESCRIPTION OF SYMBOLS 1... Electrolyte matrix, 2a, 2b... Gas diffusion electrode, 2ao... Gas flow path, 2a1... Electrode end, 3a, 3b-Separator, 4.4a-Resin membrane, 5.
...Insulating film.

Claims (1)

[Claims] 1. A fuel cell comprising a pair of gas diffusion electrodes that are arranged opposite to each other with an electrolyte matrix in between and have a gas flow path, and a separator laminated on the gas diffusion electrodes, At the end of at least one of the electrodes,
A fuel cell characterized in that an insulating layer is provided that covers an end parallel to the gas flow path and covers a bottom side of the gas flow path near the electrode end. 2. The fuel cell according to claim 1, wherein the insulating layer is formed of a resin film. 3. The fuel cell according to claim 1, wherein the insulating layer is formed of a resin film and an insulating film.