JPS58145066A - Fuel cell - Google Patents

Abstract

PURPOSE:To prevent disappearance of an electrolyte and increase a life of a cell, by forming separators with double layers of porous and fine layers in the fuel cell in which a single cell in layers through the separator. CONSTITUTION:A matrix 5 holding an electrolyte is interposed between a fuel electrode 1 and air electrode 2 through catalytic layers 11, 12, and separators 6 consisting of porous layers 21 and fine layers 20 are closely attachably arranged to gas passages 3, 4 to form a single cell. The layer 21 of the separator 6 is formed by plate shaped extracted porous carbon and carbon fiber or the like, while the layer 20 is formed by a natural graphite sheet or the like. Further the electrolyte is held in an air gap part of the layer 21 and supplemented into the matrix 5 through the electrodes 1, 2. Construction of this separator 6 can prevent disappearance of the electrolyte further improve gas sealing quality and increase a life of the cell.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel cell having an improved companion separator for separating fuel gas and air to 1%.

As shown in FIGS. 1 and 2, a conventional fuel cell has a matrix 5 for holding an electrolyte between a fuel electrode 1 having a fuel gas flow path 3 and an air electrode 2 having an air flow path 4. A plurality of unit cells 10 are stacked with separators 6 in between to prevent fuel gas and air from mixing.

Both the fuel electrode 1 and the air electrode 2 are provided with a large number of ribs to form gas passages 3.4.

Catalyst layers 11 and 12 are fixed to the flat surfaces of both electrodes 1 and 2, and an electrolyte holding matrix 5 is attached between the catalyst layers so as to be in close contact with each other. Further, the two electrodes 1 and 2 are arranged so that the gas flow passages 3 and 4 are orthogonal to each other, thereby forming a single cell. In order to prevent mixing of fuel gas and air, a separator 6 is provided between the gas flow passages 3 and 4 for each single cell.

As a means of supplying fuel gas and air to the stacked cells, manifolds 13 are installed on the four sides of the stacked cells.
are fixed, and one of the opposing manifolds is arranged as an inlet and the other as an outlet. Fuel gas and air are collectively supplied to each unit cell from this manifold 13.

In general, fuel cells need to maintain a constant temperature, so a cooling pipe 8 is provided inside each of a plurality of single cells in order to cool the excess heat generated when power is generated.

The separator 6 that separates the fuel gas from the air is made of a dense carbon plate impregnated with phenol resin or the like to prevent gas from passing through.

Further, the fuel electrode 1, the air electrode 2, and the catalyst layer 11.12 are usually made of porous carbon plates 9, which allow sufficient passage of fuel gas and air.
This is a product in which an electrolyte such as phosphoric acid is contained in SiC powder, Kynor cloth, or the like.

When hydrogen, which is a fuel gas, flows through the flow path 3, the hydrogen reaches the boundary surface of the matrix 5 through the porous fuel electrode 1 and the catalyst layer 11i. Here, an electrochemical reaction occurs, hydrogen is ionized and moved by the electrolyte, and similarly the catalyst layer 12
Oxygen 7 (reacts with air) at the interface of This is an important point.

In such conventional fuel cells, the electrolytic solution in the matrix 5 passes through the catalyst layer and the electrodes, is carried away into the fuel gas and air, and is lost, so the battery life is short. Furthermore, since the separator 6 is a carbon plate, it has poor adhesion to the electrodes and has the drawback of leakage of fuel gas and air.

The purpose of the fuel cell of the present invention is to prevent loss of electrolyte,
There is a long life fuel cell to provide all the benefits.

A feature of the present invention is that the separator is composed of at least two layers, a porous layer and a dense layer, so that full performance can be maintained for a long period of time.

Hereinafter, one embodiment of the fuel cell of the present invention will be described with reference to FIG.

A matrix 5 holding an electrolyte is sandwiched between the fuel electrode 1 and the air electrode 2 via catalyst layers 11 and 12, and the gas passage 3
．． A separator 6 consisting of a porous layer 21 and a dense layer 20 is disposed in close contact with the cell 4 to constitute a single cell.

The porous layer 21 of the separator 6 is made of a plate made of porous carbon or carbon fiber, and the dense layer 20 is made of a natural graphite sheet.

An electrolytic solution such as phosphoric acid is held in the pores of the porous layer 21, that is, the nitrogen pores, and the fuel gas and air are used to
When the electrolyte in the matrix 5 is carried away, the electrolyte can be sequentially replenished into the matrix 5 through the electrodes 1 and 2. In this way, the life of the battery can be extended.

Note that it is not always necessary to replenish the electrolytic solution from both electrodes 1 and 2.

It is not necessary that all the separators in the battery stack be the multilayer separators of the present invention, and the object of the present invention can be achieved even if they are used alternately with ordinary separators.

The dense layer 20 is flexible and highly elastic9, and makes use of this property to prevent leakage of fuel gas and air.

As described above, according to the present invention, the separator is 2*tVt
This structure can prevent the electrolyte from disappearing, improve the casing and gas seal, and have the effect of extending the life of the battery.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the stacked state of a fuel cell, Fig. 2 is a sectional view of a conventional single cell structure of a fuel cell, and Fig. 3 shows an embodiment of a single cell structure of a fuel cell of the present invention. FIG. DESCRIPTION OF SYMBOLS 1... Fuel electrode, 2... Air electrode, 3.4... Flow path, 5... Matrix, 6... Separator, 20...
...Dense layer, 2nd sentinel 3 figure 2

Claims (1)

[Scope of Claims] 1. In a device in which a plurality of unit cells each having a matrix containing an electrolyte disposed between a fuel electrode and an air electrode having a gas flow path are stacked with a separator interposed therebetween, the separator A fuel cell characterized by comprising at least two layers: a porous layer and a dense layer. 2. A fuel cell according to claim 1, characterized in that an electrolyte is stored in a porous layer of the separator.