JPH09199143A - Manufacture of solid-electrolyte fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve generating performance by larger broadening an effective electrode area. SOLUTION: In a method of manufacturing a solid-electrolyte fuel cell, powder is projected to a surface of a solid-electrolyte ceramic molded unit 1, the molded unit surface is hollowed into a rough surface, the surface-roughed molded unit surface is layered by arranging a fuel electrode 2 in one surface and an air electrode 3 in the other, this layered unit is sintered. In this powder, a solid- electrolyte material and a fuel electrode material or air electrode material are used.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for manufacturing a solid oxide fuel cell.

[0002]

2. Description of the Related Art In a solid oxide fuel cell, each layer of a fuel electrode, a solid electrolyte membrane, and an air electrode is arranged and laminated on each other to form three layers. Fuel gas is supplied and air is supplied to the air electrode to generate electricity.

In the flat plate type solid oxide fuel cell, each layer of the fuel electrode, the solid electrolyte membrane and the air electrode has a flat plate shape, and flat surfaces are arranged and laminated on each other. The air electrode may be referred to as an oxygen electrode and oxygen gas may be supplied thereto.

[0004]

The electrode reaction in this solid oxide fuel cell is considered to occur at the three-phase interface between the solid electrolyte, the electrode, and the gas phase, which improves the power generation performance of the solid oxide fuel cell. To do so, it is necessary to widen the area of the three-phase interface.

For this reason, conventionally, a method has been known in which particles having a small particle diameter are adopted as an electrode material to make the electrode finely structured to widen the effective electrode area, but the power generation performance is still satisfactory. Was not.

[0006] Therefore, an object of the present invention is to provide a method for manufacturing a solid oxide fuel cell, which can increase the effective electrode area and improve the power generation performance.

[0007]

According to a first aspect of the present invention, there is provided a method for producing a solid oxide fuel cell, wherein a powder is projected onto the surface of a solid electrolyte ceramic molded body to make the surface of the molded body depressed. It is characterized in that a fuel electrode and an air electrode are arranged on one of the surfaces of the surface of the molded body that has been roughened, and the laminated body is laminated, and the laminated body is fired.

Further, in claim 2, the powder is a solid electrolyte material.

Further, in claim 3, the powder is a fuel electrode material or an air electrode material.

With this, the interface between the electrode and the solid electrolyte membrane can be easily roughened, so that the effective electrode area of the electrode can be made larger than in the case where the electrode and the solid electrolyte membrane are respectively laminated on flat surfaces. .

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION

(Example) An example of a method for manufacturing a solid oxide fuel cell according to the present invention will be described below.

First, a method for manufacturing the solid electrolyte green sheet will be described.

A predetermined amount of a binder (eg, polyvinyl butyral binder) and a solvent (ethanol and toluene) are added to powdery yttria-stabilized zirconia to make a slurry, and a solid electrolyte green sheet is prepared by a doctor blade method. did.

Next, a method of manufacturing the fuel electrode green sheet and the air electrode green sheet which will be electrodes will be described.

The fuel electrode green sheet is made into a slurry by adding a binder (for example, polyvinyl butyral binder) and a solvent (ethanol and toluene) in a predetermined amount to a mixture of powdered nickel oxide and yttria-stabilized zirconia, and doctor blade. It was produced by the method.

On the other hand, the air electrode green sheet was prepared by the doctor blade method by adding a predetermined amount of a binder (for example, polyvinyl butyral binder) and a solvent (ethanol and toluene) to powdered lanthanum manganite to make a slurry.

Next, after stacking a predetermined number of the prepared solid electrolyte green sheets in a plastic bag, the inside of the bag is evacuated and pressure-bonded using a warm isostatic press to obtain a solid. An electrolyte type ceramic molded body was produced.

Subsequently, a shot material (particle size: 100 mesh pass) made of yttria-stabilized zirconia, which is a powder of a solid electrolyte material, is projected onto both surfaces of the obtained solid electrolyte type ceramic molded body to form a solid electrolyte type material. The surface of the ceramic molded body was dented and roughened.

Next, the green sheets of the fuel electrode and the air electrode are superposed on both sides of the solid electrolyte type ceramic molded body which has been roughened by projection and put in a plastic bag, and the inside of the bag is in a vacuum state. Then, it was pressure-bonded with a warm isostatic press.

As a result, as shown in the cross-sectional view of FIG. 1, the solid electrolyte type ceramic molded body 1 is roughened by projection.
The electrode sheets of the fuel electrode 2 and the air electrode 3 are joined along the irregularities of the surface of the solid electrolyte type ceramic molded body 1 and the fuel electrode 2, and the solid electrolyte type ceramic molded body 1 and the air electrode 3 respectively. The joint surfaces 4a and 4b were obtained in a concavo-convex state.

After this pressure bonding, the three-layer laminate of the solid electrolyte membrane, the fuel electrode and the air electrode taken out from the plastic bag was fired at a temperature of 1300 ° C. for 2 hours.

The solid oxide fuel cell having the solid electrolyte membrane with electrodes thus obtained was connected as shown in FIG. 2 and the power generation characteristics were measured.

In FIG. 2, 2 is a fuel electrode, 3 is an air electrode,
Reference numeral 5 is a solid electrolyte membrane, and 6 is a solid oxide fuel cell.
Further, 7 is a fuel gas supply pipe, 8 is an air supply pipe, 9 is a platinum wire, 10 is a variable resistor, 11 is an oscilloscope, 12 is an ammeter, and 13 is a mercury switch.

Then, the solid oxide fuel cell 6 is set to 100
While maintaining the temperature of 0 ° C., the fuel gas and the air are respectively fed through the fuel gas supply pipe 7 and the air supply pipe 8 to the fuel electrode 2,
It was supplied to the air electrode 3 to cause an electrode reaction through the solid electrolyte membrane 5. Then, while observing with the ammeter 12,
The voltage drop due to the polarization of the fuel electrode 2 and the air electrode 3 in the state where a current of 0 mA / cm ² flows was measured with the oscilloscope 11 by the current interrupt method. Table 1 shows the measurement results.

In addition, as a comparative example, a solid electrolyte fuel cell manufactured by the same method as that of the example except that the powder of the solid electrolyte material was not projected onto the surface of the solid electrolyte type ceramic molded body, that is, The measurement results of the solid electrolyte membrane having a flat surface are also shown.

[0026]

[Table 1]

The smaller the value of the voltage drop due to this polarization, the larger the effective area of the electrode and the better the performance as a fuel cell. Table 1 shows that the example product has a smaller value of voltage drop due to polarization than the comparative example product. Therefore, it is understood that the example product has a larger effective electrode area than the comparative example product.

Further, when the effective electrode areas of the joint surfaces 4a and 4b are calculated based on the sectional view shown in FIG. 1, it is about 1.2 times as large as the case where the joint surfaces are flat. However, the voltage drop due to polarization of the example product shown in Table 1 is 1
It has fallen to about 1/2. It is considered that this is because the contact surface between the solid electrolyte membrane, the fuel electrode, and the air electrode was widened due to the unevenness of the joint surface, and the adhesion was strengthened, thereby lowering the internal impedance of the solid oxide fuel cell. .

In the projection of the present invention, the powder of the fuel electrode material is formed on the surface of the solid electrolyte type ceramic molded body on the side where the fuel electrode is arranged, and the air electrode is formed on the surface of the side where the air electrode is arranged. The powder of the material can be projected, and in that case, the same effect as that of the powder of the solid electrolyte material can be obtained.

As described above, according to the present invention, the laminated interface between the electrode and the solid electrolyte membrane can be easily roughened, so that the electrode and the solid electrolyte membrane are laminated on flat surfaces as in the conventional case. The effective electrode area can be increased.

In the blast of the present invention, the powder as the blasting material is not allowed to adhere to the surface of the solid body after being dented on the surface of the solid electrolyte type ceramic compact, but to fall from the surface of the compact. I will end up. Therefore, the blast material is not limited to each powder of the solid electrolyte material, the fuel electrode material or the air electrode material, and may be any material as long as it can make the surface of the solid electrolyte type ceramic molded body hollow, for example, walnut. You may use the powder of material, the powder of carbon, etc. However, in the unlikely event that the powder remains on the surface of the solid electrolyte type ceramic molded body after the projection, it may become impurities in the powder other than the solid electrolyte material, the fuel electrode material or the air electrode material to deteriorate the characteristics. From some points, it is most preferable to use the solid electrolyte material, the fuel electrode material, or the air electrode material as the powder.

The electrodes are formed as in this embodiment.
It may be formed by stacking the green sheet of the fuel electrode or the air electrode on the solid electrolyte type ceramic molded body and press-bonding it, or the slurry or paste made of the fuel electrode material or the air electrode material on the surface of the solid electrolyte type ceramic molded body. You may form an electrode using.

[0033]

As described above, according to the present invention, the surface of the solid electrolyte type ceramic molded body can be easily roughened to widen the effective electrode area. Therefore, the power generation performance of the solid electrolyte type fuel cell can be improved. It will be possible to improve.

Further, since the contact area between the solid electrolyte membrane and the electrode is widened and the adhesion is strengthened, the internal impedance of the solid electrolyte fuel cell can be lowered, which improves the power generation performance of the solid electrolyte fuel cell. It is also possible to obtain the effect of contributing to.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a solid electrolyte membrane having electrodes on both sides according to an embodiment of the present invention.

FIG. 2 is a connection diagram for measuring power generation characteristics of a solid oxide fuel cell.

[Explanation of symbols]

 1 Solid Electrolyte Ceramic Molded Body 2 Fuel Electrode 3 Air Electrode 6 Solid Electrolyte Fuel Cell

Claims (3)

[Claims] 1. A powder is projected onto the surface of a solid electrolyte type ceramic molded body to make the surface of the molded body indented and roughened, and one surface of the roughened molded body has a fuel electrode and the other has an air electrode. Is disposed and laminated, and the laminated body is fired, and a method for manufacturing a solid oxide fuel cell. 2. The method for producing a solid oxide fuel cell according to claim 1, wherein the powder is a solid electrolyte material. 3. The method for producing a solid oxide fuel cell according to claim 1, wherein the powder is a fuel electrode material or an air electrode material.