JPS60249258A - Fuel cell - Google Patents

Abstract

PURPOSE:To increase mechanical strength of a bipolar separator by inserting a spacer comprising porous body or fibers having heat resistance and corrosion resistance into an electrolyte reservoir, for supplying electrolyte, of a bipolar separator. CONSTITUTION:Unit cells each of which consists of an anode, a cathode, and an electrolyte layer are stacked with bipolar separators having gas supply grooves 1 and electrolyte reservoirs 2 for supplying electrolyte to form a fuel cell. A spacer 3 comprising a porous body or fibers having heat resistance and corrosion resistance in an atmosphere of fuel cell operation is inserted into the electrolyte reservoir to hold electrolyte. Since spaces in electrolyte reservoirs are eliminated in the cell, breakage of thin electrode contacting the reservoir 2 caused by applying pressure is prevented. Thereby, mechanical strength is remarkably increased and reliability is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a fuel cell, and more particularly to a fuel cell equipped with an electrolyte reservoir for replenishing electrolyte.

[Technical background of the invention and its problems]

In general, a fuel cell is a battery in which an electromotive reaction proceeds by consuming a fuel gas such as hydrogen and an oxidant gas such as air. For this reason, it is necessary to constantly supply a reactive gas from outside the battery, and this supplied gas is discharged outside the battery as unreacted scum that is used as a reaction product after an electromotive reaction within the battery. It is known that this exhaust gas carries the electrolyte out of the battery at the same time as it is discharged, reducing the electrolyte volume inside the battery. This decrease in electrolyte volume is believed to be one of the causes of deterioration of battery characteristics such as crossover.

In order to prevent such deterioration of battery characteristics, many fuel cells have been devised in which the bipolar separator is provided with an electrolyte reservoir for replenishing the electrolyte.

However, the electrolyte reservoir does not create a cavity within the battery, and the thin electrode in contact with it falls into the cavity when pressurized, causing cracks and leading to damage to the battery.

[Purpose of the invention]

This invention was made to solve the above-mentioned drawbacks.
The present invention provides a fuel cell that is equipped with an electrolytic solution reservoir for replenishing the electrolytic solution, and whose mechanical strength is not impaired by the provision of the electrolytic solution reservoir.

[Summary of the invention]

The present invention provides a fuel cell that includes an electrolyte reservoir for replenishing electrolyte in a bipolar separator, and uses a material (carbon, etc.) that is heat-resistant and corrosion-resistant in the operating atmosphere of the fuel cell.

This method is characterized by inserting a compressible/incompressible spacer made of SIC, PTFg, etc. into the electrolyte reservoir.

This prevents the electrodes from being damaged due to falling into the liquid reservoir under pressure during battery stacking and operation. Furthermore, the mechanical strength of the bipolar separator can be increased by inserting the spacer.

It is capable of replenishing electrolytes and mechanically strengthens the battery.

〔Effect of the invention〕

Thus, according to the present invention, it is possible to prevent battery characteristics from deteriorating over a long period of time due to electrolyte removal, and to prevent damage caused by falling electrodes that occur during battery stacking and operation, thereby improving practicality. This makes it possible to provide a high-performance fuel cell.

[Embodiments of the invention]

The bipolar separator, which is the main part of the present invention, will be explained in detail below with reference to the drawings. FIG. 1 is a cross-sectional view of a bipolar separator body 5 with a commonly used electrolyte reservoir 2. FIG.

Embodiment 1 FIG. 2 shows a cross-sectional view of a spacer 3 made of porous material and fibers inserted into an electrolyte reservoir 2 as a spacer of the present invention. These porous bodies and fibers are used to retain electrolyte by impregnating them, but in some cases, they are impregnated with electrolyte in advance, and in other cases, only the spacer is inserted first and battery assembly is completed. Both cases are possible, with subsequent external impregnation with electrolyte.

By inserting this spacer, the mechanical strength is increased to 15 times, which is 1.5 to 2 times stronger than the spacer itself! ? /d
Even under the above pressure, no breakage was achieved.

Example 2゜Figure 3 shows particles (carbon,
81C, PTFI! A cross-sectional view when a spacer 4 made of heat-resistant and corrosion-resistant materials such as : is inserted is shown. When the particle size of the spacer is large, it is treated in the same manner as in Example 1. Furthermore, when the particle size is small, it is desirable that the fine particles be formed by kneading with an electrolytic solution and filled before battery assembly. By providing this spacer, the mechanical strength is strengthened by 1.5 to 2 times compared to that without a spacer, and the result is that it does not break even under pressure of 15 to y/d1 or more. Figure 2 is a cross-sectional view of a bipolar separator body equipped with an electrolyte reservoir for electrolyte replenishment used in the example. FIG. 3 is a cross-sectional view of a bipolar separator with an electrolyte reservoir filled with particles as a spacer according to another embodiment of the invention.

1...Gas supply groove 2... Electrolyte reservoir 3...Porous/fibrous spacer 4... Particulate spacer 5...Bipolar separator body 6.6'... Bipolar separator

Claims (1)

[Scope of Claims] α] A unit battery is constructed from an anode electrode, a cathode electrode, and an electrolyte layer, and a bipolar separator is laminated with a bipolar separator interposed therebetween; In a fuel cell equipped with an electrolyte reservoir, g in the electrolyte reservoir is
A fuel cell characterized by comprising a varnish spacer. (2) The fuel cell according to claim 1, wherein the spacer provided in the electrolyte reservoir includes a porous body that has heat resistance and corrosion resistance in the fuel cell operating atmosphere. . (2) The fuel cell according to claim 1, wherein the spacer provided in the electrolyte reservoir contains a fibrous material having heat resistance and corrosion resistance in the fuel cell operating atmosphere. C] The fuel cell according to claim 1, wherein the spacer provided in the electrolyte reservoir contains particles that have heat resistance and corrosion resistance in the fuel cell operating atmosphere.