JPS58165261A - Matrix type fuel cell - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a type of fuel cell that uses a matrix that holds an electrolyte fixed.

In fuel cells that use hydrogen gas or a hydrogen-containing gas obtained by reforming natural gas such as methane or ethane as the fuel, and oxygen or air as the oxidizing gas, the fuel gas and the oxidizing gas are directly connected. In order to prevent a decrease in power generation efficiency and dangers such as abnormal heat generation or explosion caused by the reaction, it is necessary to prevent the mixing of reaction gases inside the battery and the leakage of fuel gas to the outside of the battery as much as possible. A fixed-tier fuel cell generally has the configuration shown in FIG. That is, a porous thin film member having heat resistance, corrosion resistance, and electrical insulation properties.A porous carbon nonwoven fabric with good gas diffusion is formed with a matrix impregnated with an electrolyte such as phosphoric acid, II acid, or potassium hydroxide in the center. Electrode base material 2 consisting of etc.

3a, water-repellent layers 2b, 3b made of polytetrafluoroethylene, etc., and catalyst layers 2c, 3 made of carbon powder supporting noble metals such as platinum, a binder, etc.
a fuel electrode 2 and an oxidizer electrode 3 respectively formed from c.
are arranged in a sandwich-like manner, and these are sandwiched between conductive and airtight partition plates 4.4. The figure shows an example in which a bipolar plate is used as a separator, 5 is a fuel supply groove formed on one side of the bipolar plate 4 and constitutes a fuel gas compartment, and 6 is a fuel gas compartment formed on the other side of the bipolar plate 4. The oxidizing agent supply groove constitutes an oxidizing agent gas compartment. In the type that uses a grooved perforated plate without using a bipolar grating, fuel supply grooves or oxidizer supply grooves are formed on the opposite side of each electrode base material to the matrix, forming a grooved perforated plate, as shown in the figure. Instead of a bipolar plate, a flat gas-tight separator is provided. In either case, there is no difference in terms of sandwiching the electrode and matrix with an airtight Mll&.

By the way, in a fuel cell having the above configuration, gas leakage inside the cell is mainly caused by the electrode catalyst.
The gas leaks from the 1.degree. Therefore, the remaining path for gas leakage inside the battery is at the end of the electrode or IJ rack, and conventionally, as shown in Figure 2, a gasket 7 is placed at this end and a bipolar plate 4. It was sealed by applying pressure.

However, it is difficult to completely inspect the ends of the electrodes and matrix around the entire circumference of the packing 7. Therefore, a gas flow path is formed as shown by the arrow in Figure 2, and the fuel and oxidation There was a risk of @contact I6 occurring with the agent.

Therefore, an object of the present invention is to provide a structure that can eliminate gas leakage at such end portions.

This purpose, according to the hon., is achieved by gas-sealing the ends by means of a pressure-bearing matrix body, so that D□, □-□
4. □K RIf f myushi・this rank ＾：″surname’i
It is said to act as a matchmaker.

FIG. 3 is a partial sectional view of the non-inventive embodiment, in which the same parts as in FIG. 1 are given the same reference numerals. As is clear from the figure, the matrix 1 extends close to the end of the bipolar plate 4 at the distance IL&, whereas the fuel electrode 2 is located within the step 8 formed around the bipolar plate 4. Thus, Bibo 2 Plate and Matrix I! A portion 9 in contact with L& is formed. As a result, fuel gas attempting to escape from the fuel electrode substrate 2a through the end of the electrode encounters the matrix 1 with high sludge pressure and is prevented from advancing further.

Note that the 11t electrode 3 of the oxidizing agent and the shoulder surface of the matrix 1 may be sealed with a 10t trowel of an ordinary sealing material.

By the way, since the present invention is based on the assumption that the matrix and the gas vent have a pressure (total 0°5 to 2 kg/j), the matrix must always be impregnated with and retained a sufficient amount of electrolyte. be. Therefore, in the example shown in FIG.
A monument 11 and a replenishment hole 12 with a liquid volume adjustment function of 111L are provided. By taking this measure,
The grooves 11 absorb changes in the amount of electrolyte in the matrix during operation or rest of the fuel cell, and therefore the matrix 1 can always maintain a high gas sealing force, making it possible to further ensure the effects of the present invention. It goes without saying that the present invention can also be applied to a structure using a grooved perforated plate, and a similar structure can also be applied to the oxidizer electrode side.

[Brief explanation of the drawing]

Figure 1 is a mm diagram of an example of a matrix fuel cell, II
Figure Z is a sectional view of a portion 1lIr showing an example of a conventional gas seal structure, and Figure 3 is a sectional view of a component of an embodiment of the present invention. :Bound・Fly) Zu 2 Figure T 3 Figure

Claims (1)

[Scope of Claims] 1) A fuel electrode and an oxidizer electrode each consisting of an electrode base material, a water repellent layer, and a catalyst layer are connected to each other by sandwiching a high-pressure matrix in the center that holds an electrolyte and has a gas vent. In a fuel cell a#, the matrix is arranged to face each other and sandwiched between airtight separators, and the matrix is extended to near the end of the separator, and at least the fuel
[A matrix-type fuel characterized by forming a step approximately equal to the thickness of the electrode on the end surface of the separator that contacts the electrode, accommodating the electrode within this step, and using the peripheral edge of the matrix as a gas seal. battery. 2. In the fuel cell according to claim 1, the peripheral portion of the matrix includes an electrolyte storage portion! Matrix type fuel cell.