JPH03276565A - Solid electrolyte fuel cell - Google Patents

Abstract

PURPOSE:To facilitate manufacture by laminating cell units on both faces of a thin zirconia ceramic, feeding the fuel gas to a porous conducting material of one of the cell units to form a fuel chamber, and feeding the oxygen- containing gas to a porous conducting material of the other to form an oxygen chamber. CONSTITUTION:Multiple cell units 14 each provided with plate-shaped porous conducting materials 13a, 13b on both faces of a thin zirconia ceramic (zirconia plate) 12 are laminated via inter-connectors 15. The fuel gas such as H2 gas or CO gas is fed to one porous conducting material 13a of each cell unit 14 to form a fuel chamber 16, and the oxygen-containing gas such as air is fed to the other porous conducting material 13b to form an oxygen chamber 17. Individual component members are formed into a flat shape, and the machining of the component members is facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial Application Field" The present invention relates to fuel cells, and particularly to so-called third generation solid oxide fuel cells.

"Prior Art" A fuel cell is a battery that uses, as an active material, a chemical substance normally used as a fuel, such as hydrogen or carbon monoxide. In other words, it is a device that electrochemically performs the oxidation reaction of fuel and directly converts the free energy change in the oxidation process into electrical energy. Various studies are being conducted toward the realization of

Depending on the electrolyte used and the operating temperature, such fuel cells can be of first generation (phosphate type, low temperature type), second generation (molten carbonate type, medium temperature type) and third generation (solid electrolyte type, high temperature type). Until now, development has been focused on the first and second generations.

On the other hand, research is progressing domestically and internationally on third-generation solid oxide fuel cells, which are believed to be capable of generating electricity with higher efficiency. To date, the specific cell structures of this third generation solid oxide fuel cell are known as tube type and flat plate type.

Among these, the flat plate type can have a leaner structure and can be made smaller than the tube type.

A monolithic fuel cell shown in FIG. 5 is known as a typical type of this flat plate fuel cell. In this monolithic fuel cell, an anode 2 is formed on one side of a solid electrolyte 1 made of a corrugated plate-shaped oxide ion conductive material such as stabilized zirconia, and a cathode 3 is formed on the other side to form a cell 4. However, a large number of cells 4 are stacked together via interconnectors 5. Also, in each cell 4,
A fuel chamber 6 through which fuel gas flows and an oxygen chamber 7 through which oxygen-containing gas flows.
are formed alternately.

``Problem to be solved by the invention'' However, since this monolithic fuel cell uses a solid electrolyte formed into a corrugated plate shape as described above, it is extremely difficult to form cells and stack a large number of cells. It was difficult and difficult to manufacture.

In addition, the cell itself has low mechanical strength and is easily broken, making it difficult to put it into practical use.

This invention was made in view of the above circumstances, and aims to provide a solid oxide fuel cell that is easy to manufacture and has excellent mechanical strength.

"Second Means to Solve the Problem - The solid oxide fuel cell of the present invention has a plate-shaped porous conductive material provided on both sides of a thin plate-shaped zirconia ceramic serving as a solid electrolyte! A plurality of cell units are stacked together via connectors, and fuel gas is supplied to one porous conductive material of each cell unit to form a fuel chamber, and oxygen-containing gas is supplied to the other porous conductive material to generate oxygen. The above problem was solved by forming and configuring the chamber.

"Function" In the solid oxide fuel cell of the present invention, fuel gas is supplied to the porous conductive material on one side of the thin zirconia ceramic of each cell unit to form a fuel chamber, and the porous conductive material on the other side is By supplying an oxygen-containing gas to the conductive material to form an oxygen chamber, an electromotive force is generated between the porous conductive materials or between the electrodes formed on both surfaces of the thin plate-like zirconia ceramic. In the solid oxide fuel cell of the present invention, since all of the constituent members are flat, each constituent member can be easily processed.

By sandwiching thin plate-shaped zirconia ceramics between porous conductive materials, the thin and fragile zirconia ceramics are reinforced, and the mechanical strength is increased when the whole is assembled.
The assembly process is also simple.

Furthermore, it is easy to change the thickness of each layer, and by forming each layer thinner, it can be made thinner than a conventional flat plate fuel cell.
Miniaturization becomes possible.

Embodiment FIG. 1 and FIG. 2 are diagrams showing an embodiment of the present invention, and reference numeral II in the figures indicates a solid oxide fuel cell (hereinafter referred to as a fuel cell).

This fuel cell 11 is made of thin plate-like zirconia ceramics (
A cell unit 1 (hereinafter referred to as a zirconia plate) in which plate-shaped porous conductive materials 13a and 13b are provided on both sides of the zirconia plate 12.
4 are stacked together via an interconnector 15.

One porous conductive material of each cell unit 14 +
A fuel gas such as H, gas or CO gas is supplied to 3a to form a fuel chamber 16, and the other porous conductive material +3
An oxygen-containing gas such as air is supplied to oxygen chamber 1.
7 is formed.

The luconia plate 12 functions as a solid electrolyte (oxide ion conductor), and is preferably a thin plate material of stabilized zirconia made of norconium dioxide as a matrix and to which a stabilizer such as yttria or Carnoy is added. used. It is desirable to use a material that is densely sintered and has no gas permeability as the zirconia plate. If this zirconia plate is not dense, gas will pass through it and fuel or oxygen will not be sufficiently ionized. Densely sintered zirconia plates exhibit relatively high oxide ion conductivity at high temperatures (approximately 1000°C), are stable and have strong mechanical strength, are relatively inexpensive, and are a solid material for fuel cells. Particularly excellent as an electrolyte material.

In addition, the porous conductive materials 13a and 13b must have good air permeability and conductivity, and the side to which fuel scum is supplied and which will become the fuel chamber 16 must be stable in a reducing atmosphere, and must be air-permeable. The side to which an oxygen-containing gas such as the like is supplied and becomes the oxygen chamber 17 needs to have oxidation resistance that can withstand an atmosphere containing oxygen at 1000°C.

Examples of suitable materials for these porous conductive materials 13a and I3b include the porous conductive material 13a on the fuel chamber 16 side;
As for nickel or cobalt alone or alloy,
Materials such as porous metal materials formed porous by methods such as powder metallurgy and cermets of nickel and zirconia are preferably used. Further, as the porous conductive material 13b on the oxygen chamber 17 side, LaMn0:+, LaS rM n
Conductive ceramics such as O 3, LaN I 03, and LaC003, and expensive noble metals with high melting points such as platinum are used.

In addition, the upper ε self interconnector 15 is connected to the cell unit 14.
In order to connect a large number of cell units in series, the previous stage cell unit 14
The porous conductive material 13b on the oxygen chamber 17 side serves as an anode.
and the fuel chamber 1 which becomes the cathode of the next stage cell unit 14.
This is for electrically connecting the porous conductive material 13a on the side 6 and separating the fuel chamber 16 and the oxygen chamber 17.

This interconnector 15 has good conductivity,
A plate material that is stable in a reducing atmosphere and a high temperature oxidizing atmosphere and has no gas permeability is used, and in particular, LaCro 3 or a ceramic thin plate material with Sr added thereto is preferably used.

The fuel cell 11 constructed in this way supplies a fuel gas such as H, gas, or CO gas to the porous conductive material 13a on one side of the zirconia plate 12 of each cell unit 14 to open the fuel chamber 16. and porous conductive material 1 on the other side.
These porous conductive materials 13a, 1
3b becomes a cathode and an anode, respectively, and an electromotive force is generated between them. Furthermore, in this fuel cell II,
A large number of cell units 14 are connected in series by interconnectors 15, and electric power can be extracted by providing nonporous electrodes on both outermost surfaces of the fuel cell 11 and connecting these through an external circuit.

In this fuel cell 11, since all the constituent members are flat, it is easy to process each constituent member, and the assembly process of stacking a large number of each constituent member to form the fuel cell 11 is also easy. Since it is simple, manufacturing of the fuel cell becomes easy and costs can be reduced.

In addition, by providing a plate-shaped porous conductive material on both sides of the thin zirconia plate 12, the fragile zirconia plate 12 is reinforced, and the mechanical strength of the entire fuel cell is increased, making it a practical fuel. A battery can be constructed.

Furthermore, it is easy to change the thickness of each layer, and by forming each layer thinner, it can be made thinner than a conventional flat plate fuel cell.
It becomes possible to downsize.

FIG. 3 shows another embodiment of the invention,
Reference numeral 18 is a fuel cell. This fuel cell 18 is constructed with almost the same components as the fuel cell 11 in the previous embodiment, and also has a cathode 19 formed on one side of the zirconia plate I2 and an anode on the other side. 20 valves 2
1. It is constructed by using a fair plate 21 with inner and outer lightning.

The cathode 19 and the anode 1;' 20 have high electronic conductivity and are adhesive to the Zilfair plate 12.
A material with appropriate pores is used.

As the cathode 19, porous nickel or a cermet material of nickel and zirconia, which is stable in a reducing atmosphere, is suitably used, and as the anode 20, LaMnO3, LaSrM
nO3 is preferably used.

Similar to the fuel cell 11 in the previous embodiment, this fuel cell 18 is made of a porous conductive material + 3 al, :Ht gas, C
A fuel chamber 16 is formed by supplying fuel residue such as O gas,
By supplying oxygen-containing waste such as air to the porous conductive material 13b on the other side to form the oxygen chamber 17, an electromotive force is generated between the cathode 19 and the anode 20, which are provided with the zirconia plate 12 in between. . As shown in Figure 4, when H,, Co is used as the fuel gas, the chemical formula is as follows: Anode: Ot -20''-(1,) (zirconia plate) Cathode: H, +CO-H , 0 - CO2 (2) On the anode side, 02 dissociates to produce 02-, which passes through the solid electrolyte.As a result, a flow of e- is generated and an electromotive force is generated.

Further, in this fuel cell 18, a large number of cell units are connected in series by an interconnector 15, and as shown in FIG. Power can be extracted by connecting through an external circuit.

This fuel cell 18 provides the same effects as the fuel cell 11 in the previous embodiment.

"Effects of the Invention" As explained above, in the solid oxide fuel cell of the present invention, since all of the constituent members are flat, it is easy to process each constituent member, and each constituent member can be easily processed. Since the assembly process of stacking a large number of fuel cells to form a fuel cell is also simple, manufacturing of the fuel cell becomes easy and costs can be reduced.

In addition, by providing a plate-shaped porous conductive material on both sides of the thin zirconia plate, the fragile zirconia plate is reinforced.
Since the mechanical strength of the entire fuel cell is increased, a practical fuel cell can be constructed.

Furthermore, it is easy to change the thickness of each layer, and by forming each layer thinner, it can be made thinner than a conventional flat plate fuel cell.
Miniaturization becomes possible.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the present invention, in which FIG. 1 is a sectional view of a fuel cell, FIG. 2 is an enlarged view of part A in FIG. 1, and FIGS. 4 shows another embodiment of the present invention, FIG. 3 is a sectional view of the fuel cell, and FIG. 4 is a sectional view of the fuel cell.
The figure is a schematic configuration diagram for explaining the operating principle of this fuel cell, and FIG. 5 is a sectional view showing an example of a conventional flat plate fuel cell. 11.18 Fuel cell (solid electrolyte fuel cell) 12 Zirconia plate 3 Porous conductive material 4 Cell unit 5 Interconnector 6- Fuel chamber 7...Oxygen chamber 9...Cathode (fuel electrode) 0...Anode (oxygen electrode)

Claims (1)

[Claims] A plurality of cell units each having a plate-shaped porous conductive material provided on both sides of a thin plate-shaped zirconia ceramic serving as a solid electrolyte are stacked together via interconnectors, and the porous conductive material on one side of each cell unit A solid oxide fuel cell characterized in that a fuel chamber is formed by supplying fuel gas to the other porous conductive material, and an oxygen chamber is formed by supplying an oxygen-containing gas to the other porous conductive material.