JPH034452A - Structure of unitary solid electrolyte fuel cell - Google Patents

Abstract

PURPOSE:To obtain the subject fuel cell easily and in a short time by making this in a simple shape that an oxygen electrode, a solid electrolyte, and a fuel electrode are respectively laminated in order in cylindrical shape. CONSTITUTION:For a simple battery 10, oxidizing gas such as air is supplied continuously from a gas supply pipe 14 into inside, and fuel gas such as hydrogen gas, etc., is used for the atmosphere at the periphery, whereby electrochemical oxidizing and reducing reactions occur through a solid electrolyte 12 resulting from the difference of oxygen concentration between both the inside and outside of the solid electrolyte 12. As a result, electromotive force occurs such as that an oxygen electrode 11 becomes an anode and a fuel electrode 13 becomes a cathode. It follows that the electrodes 11 and 13 are formed, respectively, on both sides of the inside and outside of the solid electrolyte 12 this way, and that the electrode 13 at the outermost layer is exposed to the outside as it is, but the electrode 11 on the inner periphery side is lead out to the outside through the gas supply pipe 14 leading to this. Hereby, if each element such as the solid electrolyte 12, etc., is formed in order to the outer periphery of the element on the inner periphery side, that will do, and unefficient work such as masking, etc., can be obviated, and work efficiency in manufacturing can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to the structure of a single fuel cell, that is, a unit cell, which generates an electromotive force through oxidation and reduction reactions via a solid electrolyte.

As is well known in the art, a solid electrolyte fuel cell has a porous M element electrode 2 and a fuel electrode 3 sandwiching a solid electrolyte 1 having oxygen ion selective permeability, as shown in principle in FIG. Supplying oxidizing gas such as air or oxygen gas to the oxygen electrode 2 side,
On the other hand, a fuel gas such as hydrogen gas or carbon monoxide gas is supplied to the fuel electrode 3N, and oxygen ions permeate through the solid electrolyte due to the difference in oxygen concentration on both sides of the solid electrolyte 1, causing oxidation. An oxidation/reduction reaction occurs between the gas and the fuel gas, and the resulting electromotive force is transferred from each electrode 2゜3 to the load 4.
It is to be taken out. As this solid electrolyte 1, yttria-stabilized zirconia (YS2), calcia-stabilized zirconia (C8Z), etc. are known.
A velorskite-type lanthanum-based composite oxide is known as a fuel electrode 3, and nickel, a nickel alloy, or Ni-ZrO2 cermet is also known as a material for the fuel electrode 3.

The voltage obtained by the above oxidation/reduction reaction via the solid electrolyte 'J(1) is only about 1 V at most, and the 74 current increases with the reaction area, so in order to put it into practical use, the above structure is required. It is necessary to connect a large number of cells in series and parallel with each other in a basic structure with an expanded reaction area.The structure of the cell for this purpose is, for example, to form a solid electrolyte into a cylindrical shape, and to attach an oxygen electrode and a fuel electrode to the inner and outer surfaces of the cell. The cylindrical shape and the solid electrolyte are formed into a corrugated shape, and oxygen electrodes and fuel electrodes are provided on both sides of the solid electrolyte, and these are sandwiched at a predetermined interval by interconnectors, which are conductive flat plates, to perform oxidation. Flat plate type cells with flow paths for oxidizing gas and fuel gas are known.Of these, flat plate type cells are easy to make compact, but two cells with surface contact between the flow paths for oxidizing gas and fuel gas are known. Since the cells are divided into sections, they have the disadvantage of poor sealing performance.On the other hand, cylindrical cells have a structure that separates the inner and outer peripheries, so they have excellent sealing properties. Fig. 3 is a schematic diagram showing an example of a cylindrical cell, in which an oxygen electrode 2 is provided on the entire outer circumferential surface of a support tube 5 made of a ceramic material such as alumina and having a porous 4M structure. At the same time, Ni and la (
:, r03, etc., and a solid electrolyte 1 is formed on the outer surface of the oxygen electrode 2 so that the interconnector 6 is exposed to the outside. A fuel electrode 3 is formed in this state. Note that the cell shown in FIG. 3 is of a so-called non-self-supporting type, and a self-supporting cell may have a structure in which the support tube 5 is omitted.

Problems to be Solved by the Invention By the way, many of the elements such as the solid electrolyte 1 in the unit cell having the above-described structure are made of ceramic materials.
Therefore, conventionally, the solid electrolyte layer, each electrode, etc. are formed by methods such as chemical vapor deposition (CVD), electrochemical vapor deposition (EVD), or thermal spraying. However, in manufacturing a unit cell having the structure shown in FIG.
Alternatively, the oxygen electrode 2 is formed by attaching it by a method such as thermal spraying, and then nickel or LA Qr is applied while masking the area except for the area where the interconnector 6 is to be formed.
An interconnector 6 is formed by attaching Oj3 or the like to the exposed portion of the outer surface of the oxygen electrode 2 by EVD or thermal spraying, and then with the interconnector 6 masked, itria stabilized zirconia (YSZ) or the like is deposited by EVD or thermal spraying. A layer of solid electrolyte 1 is formed by depositing the solid electrolyte 1 by a method such as thermal spraying, and then Ni, Ni cermet, etc. is deposited by a method such as slurry coating or thermal spraying with the interconnector 6 and its surrounding area masked to form a fuel electrode. form 3. Therefore, with the above-mentioned conventional cell structure, masking is required multiple times during the manufacturing process, and since masking is a detailed manual operation, it takes a long time to manufacture the cell, resulting in poor manufacturing efficiency. There was some inconvenience.

This invention was made against the background of the above-mentioned circumstances, and it is an object of the present invention to provide a fuel cell unit having a structure that can be easily manufactured without deteriorating its electrical characteristics.

Means for Solving the Problems In order to achieve the above object, the present invention provides one of an oxygen electrode and a fuel electrode on the inner peripheral surface of a cylindrical solid electrolyte, and also The other electrode is provided on the outer peripheral surface, and a conductive gas supply pipe is inserted inside the inner electrode, and the gas supply pipe is electrically connected to the inner electrode. This is a characteristic feature.

Function: In the unit cell of this invention, electrodes are formed on both the inner and outer sides of the solid electrolyte, and the outermost electrode is exposed to the outside as it is, but the inner electrode is electrically connected to it. The gas is led out via a gas supply pipe. Therefore, unlike conventional interconnectors, there is no member or part that penetrates in the radial direction, so each element such as a solid electrolyte can be formed sequentially on the outer peripheral surface of the inner peripheral element, which requires inefficient work such as masking. This improves manufacturing workability.

Example Next, embodiments of the invention will be described with reference to the drawings.

FIG. 1 is a schematic perspective view showing one embodiment of the present invention, and a cell 10 shown here has a cylindrical shape with a closed tip, the innermost layer of which is an oxygen electrode 11, and the outer periphery of the cell 10. A layer of solid electrolyte 12 is formed on the surface, and a fuel electrode 13 is further formed on the outermost layer. And gas supply in the center
g14 is inserted and its tip extends to near the tip of the cell 10, and this gas supply pipe 14 and oxygen electrode 11
A conductive member 15 with good air permeability is filled between the inner circumferential surface and the inner circumferential surface of the conductive member 15 .

The oxygen electrode 11 is la +-xSr
It is a porous structure made of perovskite-type lanthanum-based composite oxides such as 3 and LAQo 03, and these materials are attached to the outer circumferential surface of a predetermined core material to a predetermined thickness using methods such as CVD or thermal spraying. It is formed by In addition,
The core material is extracted or removed in a subsequent process.

In addition, the solid electrolyte 12 is made of YSZ or C8z as in the past, and is made by depositing YSZ or the like on the entire outer peripheral surface of the oxygen electrode 11 to a predetermined thickness by a method such as EVD or thermal spraying. It is formed. Further, the fuel electrode 13 is made of Ni or Ni cermet, and has a porous structure formed by applying the slurry to the entire outer circumferential surface of the solid electrolyte 12 and then firing or thermal spraying the material. is formed. On the other hand,
The gas supply pipe 14 supplies an oxidizing gas such as air or oxygen gas to the inner circumferential side of the oxygen electrode 11, and serves as one electrode or terminal, and is electrically conductive and chemically resistant at high temperatures. A highly stable material, such as the oxygen electrode 11
The rear end is made of the same material as the single cell 1.
Extruded from 0. Further, the conductive material 15 is for electrically connecting the oxygen electrode 11 and the gas supply pipe 14, and is formed into a felt shape to ensure breathability. The oxygen electrode 11 is made of a material that is stable, for example, the same material as the material that makes up the oxygen electrode 11.

The unit cell 10 configured as described above continuously supplies an oxidizing gas such as air through the gas supply pipe 14, and
By setting the outer atmosphere to a fuel gas such as hydrogen gas, an electrochemical oxidation/reduction reaction occurs through the solid electrolyte 12 due to the difference in oxygen concentration between the inside and outside of the solid electrolyte 12, and the oxygen electrode An electromotive force is generated such that 11 serves as an anode and the fuel electrode 13 serves as a cathode. Since the gas supply pipe 14 is electrically conductive and electrically connected to the oxygen electrode 11, the gas can be output from the gas supply pipe 14 and the outermost fuel electrode 13.

Furthermore, as is clear from its IR structure, the above cell 1Q has an oxygen electrode 11 made in a cylindrical shape, and a solid electrolyte 1 on its outer periphery.
It can be manufactured by sequentially forming the fuel electrode 2 and the fuel electrode 13, and in the process there is no need to perform troublesome work such as masking to partially make different materials.

In addition, although the above embodiment has been explained by taking as an example the single cell 10 having a structure with a closed tip, the present invention is not limited to the above embodiment, and the present invention is not limited to the above embodiment. It can also be applied to single cells. Further, the means for connecting the gas supply pipe to the electrode on the inner peripheral side is not limited to the above-mentioned felt material.

Effects of the Invention As is clear from the above explanation, the single fuel cell of the present invention has a simple shape in which the oxygen electrode, the solid electrolyte, and the fuel electrode are stacked one after another in a cylindrical shape. Since there is no need to use different materials in some parts, there is no need to intervene in troublesome operations such as masking in the manufacturing process.However, according to this invention, it can be easily manufactured in one time, and in continuous large quantities. A fuel cell unit suitable for production can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a perspective view schematically showing an embodiment of the present invention, FIG. 2 is a principle diagram of a solid electrolyte fuel cell, and FIG. 3 is a sectional view of a conventional cylindrical unit cell. 10... Cell, 11... Oxygen electrode, 12...
- Solid electrolyte, 13... Fuel electrode, 14... Gas supply pipe, 15... Conductive material. 1 Figure 2

Claims (1)

[Claims] One electrode, an oxygen electrode or a fuel electrode, is provided on the inner peripheral surface of the cylindrical solid electrolyte, and the other electrode is provided on the outer peripheral surface of the solid electrolyte, and a conductive electrode is provided inside the inner peripheral electrode. A single solid electrolyte fuel cell structure in which a gas supply pipe is inserted and the gas supply pipe is electrically connected to the electrode on the inner peripheral side.