JPH08185882A - Manufacture of solid electrolytic fuel cell - Google Patents

Abstract

PURPOSE: To obtain a method for a solid electrolytic fuel cell of tubular and horizontal stripe type. CONSTITUTION: Regarding the manufacture of a solid electrolytic fuel cell of tubular and horizontal stripe type, films up to a fuel electrode 12 and an electrolyte 13 or an interconnector 15 are sequentially formed on a primarily baked substrate tube 11 by use of the slurry sintering method. Thereafter, the substrate 11 with the films is baked in an integrated state, thereby forming a dense electrolytic film. Then, an air electrode 14 as well as the interconnector 15 are filmed and baked with the slurry sintering method or the flame splaying method for forming the cell.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a cylindrical horizontal stripe type solid oxide fuel cell.

[0002]

2. Description of the Related Art Solid oxide fuel cells are roughly classified into a cylindrical type and a flat type. Of these, the cylindrical type is shown in FIG.
The vertical stripe type (cylindrical single element type) shown in FIG. 5 and the horizontal stripe type (cylindrical multi-element type) shown in FIG.

In the cylindrical vertical stripe type (cylindrical single element type) solid oxide fuel cell 01 shown in FIG. 4, an oxygen electrode 012, an electrolyte 013, and a fuel electrode 0 are formed on the surface of a porous support tube 011.
14 and the interconnector 015 are sequentially provided. On the other hand, a cylindrical horizontal stripe type (cylindrical multi-element type) solid oxide fuel cell 02 shown in FIG.
1, a fuel electrode 024, an electrolyte 023, an interconnector 025, an air electrode 022, and a protective film 026 are sequentially provided on the surface of No. 1.

As a method for manufacturing the above solid oxide fuel cell, a thermal spraying method, a sintering method, an EVD method or a CVD method is known. Among them, in manufacturing a cylindrical solid oxide fuel cell, Currently, plasma spraying or EVD is the established method for obtaining a dense electrolyte membrane.
Film formation by the method is mainly performed. Further, in the case of the cylindrical vertical stripe type cell, in addition to the above-described film forming method, an attempt is made to form a film by a sintering method in which a raw material powder of an electrolyte is slurried and applied on a base material and baked.

However, in the sintering method, the electrolyte membrane shrinks and cracks or peels off during firing. Therefore, a water-absorptive mold such as gypsum is used to sequentially deposit each slurry of the electrolyte and the electrode (fuel electrode or air electrode). Attempts have been made such as casting and firing it integrally, or applying an electrolyte to an unfired electrode (fuel electrode or air electrode) molded body and firing it integrally.

[0006]

In the former film forming method using the thermal spraying method or the EVD method, the film forming process is complicated, a single film forming process requires a considerable amount of time, and the raw material yield is high. Unfortunately, the manufacturing equipment is expensive. Therefore, there is a problem that productivity is poor and it is extremely difficult to cope with mass production in terms of manufacturing cost.

Further, the development of a dense electrolyte film forming technique by the sintering method is mainly conducted for vertical stripe type cells, and there is almost no application example to the vertical stripe type cells.

Further, there is a problem in that it is structurally difficult to directly apply the method of forming a composite molded body of an electrolyte and a fuel electrode by a casting method or the like and firing it integrally to a horizontal stripe type cell.

In view of the above problems, the present invention is directed to the production of a cylindrical horizontal stripe type solid electrolyte fuel cell, in which a dense electrolyte membrane is formed by a sintering method, and a cylindrical horizontal stripe solid electrolyte fuel having the same is formed. An object is to provide a method for manufacturing a battery.

[0010]

A method for manufacturing a solid oxide fuel cell according to the present invention, which achieves the above object, is a method for manufacturing a cylindrical horizontal stripe type solid oxide fuel cell, in which a calcined porous substrate tube is used. The fuel electrode, the electrolyte, and the interconnector are sequentially formed on the upper surface by the slurry sintering method, and then baked together to form a dense electrolyte membrane, and then the air electrode and the interconnector are formed by the slurry sintering method. It is characterized in that the cell is formed by firing or by forming a film by a thermal spraying method.

In the method for producing a solid oxide fuel cell, the base tube material is composed of calcia-stabilized zirconia (CSZ) and nickel oxide (NiO) as a second component.
It is characterized in that cerium oxide (CeO ₂ ) or the like is added to produce an integrally fired body.

In the method for manufacturing a solid oxide fuel cell, the fuel electrode material may be a mixture of nickel oxide (NiO) and yttria-stabilized zirconia (YSZ) or spinel oxide (MgAl ₂ O ₄ ). Characterize.

In the method for producing a solid oxide fuel cell, when the air electrode material is formed into a film by either a slurry sintering method or a thermal spraying method, A _X B _(1-X) CO ₃ (A, B,
In a perovskite type oxide represented by (C is a metal), A is La, B is any one of Sr, Ca and Ba, and C is one of Mn and Co.

In the method for manufacturing a solid oxide fuel cell, when the interconnector material is formed into a film by a slurry sintering method, A _X B _(1-X) CO ₃ (A, B and C are metals) is used. In the perovskite type oxide represented, A is La, B is any one of Sr, Ca, Ba, C is Cr, and when a film is formed by the thermal spraying method, a heat-resistant alloy (Ni-Al or It is a cermet of Ni-Cr) and Al ₂ O ₃ .

The contents of the present invention will be described in detail below.

Here, in the present invention, since a dense electrolyte membrane is formed by a sintering method in a cylindrical lateral stripe type cell,
A step of forming a base tube by extrusion molding, etc. and calcining to a strength that can withstand handling to produce a porous base tube, and forming and drying a fuel electrode and an electrolyte on the base tube in sequence by the slurry method. Then, the solid oxide fuel cell is to be manufactured from the step of integrally firing and the step of individually forming the air electrode and the interconnector by a sintering method or a thermal spraying method.

In the above manufacturing process, when the interconnector is formed into a film by the sintering method, the fuel electrode, the electrolyte and the interconnector are sequentially formed into a film on the substrate tube by the slurry method, dried, and integrally fired. After that, the air electrode is formed into a film by a sintering method or a thermal spraying method.

In the above manufacturing process, the base pipe, the fuel pipe,
For integral firing of electrolyte or interconnector,
In order to prevent damage such as cracking or peeling of constituent films such as electrolyte membrane due to shrinkage difference due to sintering between constituent members, use a calcined base tube and give the base tube a certain amount of shrinkage during integral firing. With respect to the other constituent members, the particle size distribution of the materials used or the slurry conditions are optimized so that the shrinkage ratio of each constituent member is made as close as possible to that of the electrolyte.

In the above manufacturing process, in order to prevent damage such as cracking or peeling of constituent films such as an electrolyte membrane due to a difference in thermal expansion between the constituent members, which is a problem in heat history during firing and cooling, each constituent member is prevented. As a material used, the coefficient of thermal expansion of the electrolyte is made to be as close as possible to that of other constituent members.

In the above manufacturing process, examples of materials used for the respective constituent members satisfying the above conditions are as follows. However, the material used in the method according to the present invention is not limited to these, and is not limited to this as long as it has substantially equivalent properties and properties close thereto.

The base tube material is mainly composed of calcia-stabilized zirconia (CSZ), nickel oxide (NiO),
It is preferable to use a material to which a second component such as cerium oxide (CeO ₂ ) is added.

As the fuel electrode material, nickel oxide (Ni
O) and a mixture cermet of yttria-stabilized zirconia (YSZ) or spinel oxide (such as MgAl ₂ O ₄ ) may be used.

As the air electrode material, A _X B can be used in forming a film by either a slurry sintering method or a thermal spraying method.
A perovskite type oxide represented by _(1-X) CO ₃ (A, B and C are metals) is preferable, where A is La and B is Sr.
, Ca, or Ba, and C is preferably Mn or Co.

The interconnector material is preferably a perovskite type oxide represented by AxB _{(1-X )} CO ₃ (A, B and C are metals) when the film is formed by the slurry sintering method.
Here, A is La, B is any one of Sr, Ca, and Ba, and C is preferably Cr. When the film is formed by the thermal spraying method, a heat-resistant alloy (Ni-Al or Ni-Cr) and Al ₂
A mixture with O ₃ is preferably a cermet.

As the electrolyte material, it is preferable to use yttria-stabilized zirconia (YSZ), which is a typical solid electrolyte generally used.

[0026]

In the present invention, when the base tube, the fuel electrode, the electrolyte, and even the interconnector are integrally fired, the shrinkage rate and the thermal expansion rate of each constituent member are made as close as possible so that the constituent film is cracked or peeled. A dense electrolyte membrane can be formed without causing damage such as.

In this case, in particular, since the base tube is used after being calcined, the amount of shrinkage of the base tube itself can be controlled by the calcining temperature. Therefore, it is easy to make the contraction rate of the substrate tube, which has a great influence on the film forming property of the electrolyte, equal to that of the electrolyte.

Further, since the cylindrical horizontal striped cell according to the present invention has a substrate tube supporting structure, a fuel electrode, an electrolyte or even an interconnector is directly formed on a porous substrate tube and baked integrally, so that a gypsum mold or the like is used. No mold is required and the process can be simplified.

[0029]

EXAMPLES The method for producing a cell according to the present invention will be described below in more detail with reference to Examples, but the present invention is not limited to these Examples.

FIG. 1 is a sectional view of a cell manufactured by the manufacturing method according to this embodiment. FIG. 2 shows a flow chart of the cell manufacturing process in the present invention. Hereinafter, the cell manufacturing process will be described with reference to FIGS.

The material of the base tube 11 is 0 to 20 vol%
The calcia-stabilized zirconia (CSZ) added with nickel oxide (NiO) is used, and the weight ratio of the raw material powder is 65 to 7
Dispersant, binder, defoamer, and organic cellulose for controlling the filling rate are added to the solvent water so as to be 5%, and after kneading with a pressure kneader, a cylinder having an outer diameter of 22 mm and an inner diameter of 16 mm is formed by an extrusion molding machine. Molded. Then, this molded body is fired at 1100 to 1200 ° C. to obtain a calcined base tube.

Next, as the material of the fuel electrode 12, 45 to 65
vol% nickel oxide (NiO) and spinel oxide (Mg
A mixture cermet of Al ₂ O _4), dispersing agent in water solvent so that 25% to 35% by weight of the raw material powder, added together with a binder and defoaming agent to the slurry by ball mill mixing method. Further, using a slurry diluted to 8 to 10%, a film having a thickness of 0.3 to 0.5 mm is formed at a predetermined position on the masked substrate tube 11 by a dipping method. Although the fuel electrode 12 is formed into a film by the dipping method in this embodiment, a slurry coating method, a screen printing method or the like may be used.

Similarly, yttria-stabilized zirconia (YSZ) was used as the material of the electrolyte 13, and the mixture was slurried by mixing with a ball mill at a weight ratio of the raw material powder of 60 to 70%.
After diluting to 20 to 25% and forming and drying the fuel electrode 2, a film is formed at a predetermined position on the masked substrate tube 1 by a dipping method to a thickness of 0.2 to 0.3 mm. Also in this case, the method for depositing the electrolyte 13 may be the slurry coating method, the screen printing method, or the like as in the case of the fuel electrode 12.

The composite molded body of the base tube 11, the fuel electrode 12 and the electrolyte 13 obtained as described above is dried at about 100 ° C., and then integrally fired at 1450 to 1500 ° C. in the air to form the fuel electrode 12 and a dense mixture. The base tube 11 is formed with the electrolyte membrane 13.

Subsequently, as a material of the air electrode 14, La _0.9 C
Using a perovskite type oxide represented by a _0.1 MnO ₃ ,
The raw material powder was added to water as a solvent together with a dispersant, a binder and a defoaming agent so that the weight ratio was 80 to 85%, and the mixture was kneaded with a three-roller to form a paste.
2 and the electrolyte 13 are formed on a predetermined position on the substrate tube 11 by a coating method to a thickness of 0.5 to 1 mm and dried,
Bake at 1300 ° C. in air.

Although the air electrode is formed by the coating method in this embodiment, the film may be formed by the dipping method or the screen printing method like the fuel electrode and the electrolyte.

Further, the fuel electrode 12, electrolyte 13 and
Masking the base tube 11 on which the cathode and the air electrode 14 are formed.
Ni-Al / A as the material of the interconnector 15
l₂O ₃Predetermined by plasma spraying method using cermet
A film having a thickness of 0.25 to 0.3 mm is formed at the position.

Furthermore, the metal component of the interconnector material
In order to prevent the oxidation of Ni-Al, which is
A protective film 16 is formed on the alumina (A
l₂O ₃2) is formed by a plasma spraying method.

Through the above manufacturing steps, a cylindrical horizontal stripe type solid oxide fuel cell having a dense electrolyte membrane on a base tube and having cell elements connected and arranged in series can be manufactured.

FIG. 3 shows the differential pressure dependence of the gas permeation coefficient at room temperature of a cylindrical horizontal stripe type cell in which two cell elements are formed in series on a base tube by the manufacturing method according to the present invention. From FIG. 3, it can be confirmed that even when the differential pressure is 0 to 400 mmH ₂ O, the gas permeation coefficient is 10 ⁻¹ g · cc / sec or less, gas leakage is extremely small, and a dense electrolyte membrane is formed.

[0041]

As described above, in the present invention, since the base tube, the fuel electrode, the electrolyte, and even the interconnector are integrally fired, cell elements having a dense electrolyte membrane are connected and arranged in series on the base tube. A cylindrical horizontal stripe type solid oxide fuel cell can be manufactured.

The cell produced in the present invention comprises a base tube, a fuel electrode,
Since the electrolyte or the interconnector is integrally sintered, it has excellent adhesion at the interface between each component, and in particular, the overvoltage at the interface between the fuel electrode and the electrolyte, which is important for cell performance, is significantly reduced. Reduction can be expected.

Further, in manufacturing a cylindrical horizontal stripe type solid oxide fuel cell, since the base tube, the fuel electrode, the electrolyte, and even the interconnector are integrally fired, the manufacturing process can be simplified and the productivity is high. Furthermore, since most of the cell constituent films are formed by a sintering method, which has a higher raw material yield than methods such as the thermal spraying method and the EVD method, the manufacturing cost can be greatly reduced.

[Brief description of drawings]

FIG. 1 is a cell cross-sectional view of a cylindrical horizontal stripe type solid oxide fuel cell of the present invention.

FIG. 2 is a flowchart showing a cell manufacturing process in the present invention.

FIG. 3 shows the differential pressure dependence of the gas permeation coefficient of the cell manufactured according to the present invention.

FIG. 4 shows a typical cell structure of a cylindrical vertical stripe type solid oxide fuel cell.

FIG. 5 shows a typical cell structure of a cylindrical horizontal stripe type solid oxide fuel cell.

[Explanation of symbols]

11 Base Tube 12 Fuel Electrode 13 Electrolyte 14 Air Electrode 15 Interconnector 16 Protective Film (Alumina: Al ₂ O ₃ )

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical indication location H01M 8/02 Y (72) Inventor Tsukuda Hiroshi 5717-1 Fukahoricho, Nagasaki City, Nagasaki Prefecture 3 (72) Inventor Tsutomu Hashimoto 5-717-1, Fukahori-cho, Nagasaki-shi, Nagasaki Sanryo Heavy Industry Co., Ltd.

Claims (5)

[Claims] 1. A method for manufacturing a cylindrical horizontal stripe type solid oxide fuel cell, in which a fuel electrode, an electrolyte and an interconnector are sequentially formed on a calcined porous substrate tube by a slurry sintering method and then integrally formed. A solid characterized by forming a dense electrolyte membrane by firing, and then forming and firing the air electrode and interconnector by a slurry sintering method or by a thermal spraying method to form a cell. Method for manufacturing electrolyte fuel cell. 2. The method for producing a solid oxide fuel cell according to claim 1, wherein the base tube material is calcia-stabilized zirconia (CS).
A method for producing a solid oxide fuel cell, characterized in that nickel oxide (NiO), cerium oxide (CeO ₂ ) or the like is added as a second component to Z) to produce an integrally fired body. 3. The method for producing a solid oxide fuel cell according to claim 1, wherein the fuel electrode material is nickel oxide (NiO) and yttria-stabilized zirconia (YSZ) or spinel oxide (MgAl ₂ O ₄ ). A method for producing a solid oxide fuel cell, which comprises a mixture of 4. The method for manufacturing a solid oxide fuel cell according to claim 1, wherein when the air electrode material is formed into a film by either a slurry sintering method or a thermal spraying method, A _X B _{(1-X ) In the} perovskite type oxide represented by CO ₃ (A, B and C are metals), A is La and B is S
r is a Ca, or Ba, and C is any one of Mn and Co. 5. The method for producing a solid oxide fuel cell according to claim 1, wherein when the interconnector material is formed into a film by a slurry sintering method, A _X B _(1-X) CO ₃ (A, B) , C is a metal), and A is La in the perovskite type oxide represented by
B is any one of Sr, Ca and Ba, C is Cr, and when forming a film by a thermal spraying method, it is a cermet of a heat-resistant alloy (Ni-Al or Ni-Cr) and Al ₂ O _3. A method for manufacturing a solid oxide fuel cell, comprising: