JPS58164164A - Electrolyte impregnating method of fuel cell - Google Patents

Abstract

PURPOSE:To familiarize the electrolyte with an electrode reaction layer by performing a preliminary discharge at a low load after impregnating the electrolyte so as to transfer the electrolyte from a matrix layer to the electrode reaction layer in a matrix type fuel cell. CONSTITUTION:After a block cell is heated, a preliminary discharge is performed at a low load, thus the electrolyte being held in a matrix is expanded by heat and transferred to an electrode reaction layer, in addition, water is generated in fine holes of the electrode reaction layer due to the electrochemical reaction in the cell, creating a condition that the electrolyte is apt to move to part of the electrode reaction layer, thereby part of the electrolyte is transferred to the electrode reaction layer so that the electrode reaction layer is familiarized with the electrolyte. By starting a regular operation after feeding the electrolyte which is lacking in the matrix, stable electrical characteristics can be maintained for a long time with the electrolyte not being transferred to the electrode reaction layer.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrolyte impregnation method for a matrix fuel cell having a unit cell formed by sandwiching an IJ lux between electrodes. A matrix impregnated with an electrolyte is disposed between the anode electrode and the cathode electrode.

The matrix layer is generally made of a porous material having fine pores, and has a structure in which the electrolyte is held in the pores. Therefore, the matrix layer must be impregnated with a sufficient amount of electrolyte to cause an electrochemical reaction at the electrode.

If the amount of electrolyte impregnated into the matrix layer is insufficient, fuel gas (e.g. hydrogen) or oxidizer (e.g. air) will penetrate the matrix layer and reach the counter electrode.
This not only causes a decrease in the electrical characteristics of the fuel cell, but also
Direct mixing of fuel gas and oxidizer creates explosive atmosphere, which also includes the risk of explosion. Therefore, in order to operate the fuel cell for a long time without deteriorating its electrical characteristics, it is desirable to impregnate both the matrix layer and the electrode reaction layer with a sufficient amount of electrolyte to cause a smooth electrochemical reaction. .

Conventional electrolyte impregnation methods include methods of directly impregnating a matrix layer and a porous electrode reaction layer with an electrolyte;
There are known methods in which the matrix layer is made of a material that has been coated with an electrolytic solution in advance, but these methods have the following drawbacks.

If only the electrolyte matrix layer is impregnated with electrolyte and the electrode reaction layer, which has been treated with electrolyte, is not sufficiently impregnated with electrolyte, during operation, the electrolyte retaining layer I) The electrolytic solution that holds the matrix gradually moves to the electrode reaction layer, and as a result, the electrolytic solution that holds the matrix becomes insufficient, and the fuel gas or oxidizer flows into the electrode reaction layer. and reaches the counter electrode, deteriorating the electrical characteristics of the fuel cell. Therefore, before full-scale operation of the fuel cell, it is necessary to move the electrolytic solution from the matrix layer to the porous electrode reaction layer and to adjust the porous electrode reaction order [the electrolytic solution].

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for moving an electrolyte from a matrix layer to an electrode reaction layer in a matrix amount (i%) to blend the electrolyte into the electrode reaction layer. After the electrolyte is impregnated, a preliminary discharge is performed at a low load (1. After that, the insufficient electrolyte in the matrix layer is replenished to maintain the electrical characteristics of the fuel cell for a long time. III mold.

Figure 1 shows the experimental results for a 1G cell stacked block battery.The solid line shows the characteristics when full-scale operation is performed after preliminary discharge at low load and then impregnated with electrolyte. This is an example, and the dashed-dotted line shows an example of the characteristics when full-scale operation is performed from the beginning. It can be seen that block batteries that are impregnated with electrolyte and operated in full operation after preliminary discharge are able to maintain their electrical characteristics for a longer period of time at low loads.

According to this invention, by predischarging the block battery at a low load after raising the temperature of the block battery, the electrolyte retained in the transport matrix expands thermally, and the electrolyte moves to the electrode reaction layer. Due to the electrochemical reaction within the battery, water is generated in the pores in the electrode reaction layer, making it easy for the electrolyte to move to a part of the electrode reaction layer. portion moves to the electrode reaction layer, and the electrode reaction layer becomes compatible with the electrolyte. Therefore, by replenishing the insufficient electrolyte in the matrix and then starting full-scale operation, it becomes possible to maintain stable electrical X characteristics for a long time without multiple electrolytes moving to the electrode reaction layer. .

[Brief explanation of drawings]

FIG. 1 is a diagram showing the output characteristics of a fuel cell with and without implementing the present invention.

Claims (1)

[Claims] In a fuel cell having a single cell formed by sandwiching IJ Lux between the electrodes, the cell is impregnated with IJ Lux electrolyte, and then pre-discharged at a low load to impregnate the matrix plate. A method for impregnating an electrolyte in a fuel cell, which comprises applying the electrolyte to an electrode reaction layer and then replenishing the electrolyte deficiency in the matrix.