JPH04179061A - Method for forming laminate film - Google Patents

Abstract

PURPOSE:To lessen warp of a laminate film at the time of combustion and prevent drop of the performance of a solid electrolyte fuel cell by laminating a fuel electrode material, solid electrolyte material, and oxygen electrode material one over another, followed by baking process to provide a laminate film, heating this film at a certain temp., and pressing it with a specified surface pressure load with a ZrO material interposed. CONSTITUTION:A laminate film is formed from solid electrolyte 15 and electrodes 14, 16 and subjected to a baking process, and re-heating is made at a temp. below the baking temp. while a load is applied in order to flatten warps generated in the film. Therein a material is interposed which has less reactivity in order to prevent reaction of the electrodes 14, 16 with an object 12 to be placed on the film for the purpose of applying load. That is, the laminate film consisting of the fuel electrode material 14, solid electrolyte material 15, and oxygen electrode material 16, which were laminated and baked, is heated to a temp. between 1100-1250 deg.C, and pressure is applied with a surface pressure load between 4-7gf/cm<2> with ZrO material interposed. Thereby warp of laminate film at the time of combustion is lessened, and the solid electrolyte fuel cell is prevented from drop in the performance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for forming a laminated film for smoothing a laminated film in which a fuel electrode material, a solid electrolyte material, and an oxygen electrode material are laminated and sintered.

[Conventional technology] FIG. 4 is a schematic explanatory diagram of the fuel electrode.

In the figure, la and lb are blocks each made of ZrO□. An electrolyte 2 and electrodes 3a and 3b are sandwiched between these blocks la and lb. In addition, the electrode 3a
, 3b are pasted with PT foils 4a, 4b with holes formed therein, respectively. This is to ensure smooth flow of electricity. In power generation, oxygen ions move through the electrolyte 2 from the air electrode side 5 and reach the fuel (H2, Co, etc.) electrode side 6.
Here, it reacts with the fuel to generate H2 and CO2. At this time, since the oxygen ions release electrons, an excess of electrons exists on the fuel electrode side 6. Conversely, there is a shortage of electrons on the air electrode side 5. Therefore, if each electrode is connected with a material that allows electrons to pass, such as a PT wire, electricity will flow through the PT wire, and the above reaction will proceed smoothly.

A fuel cell is a system that directly converts the chemical energy of fuel into electrical energy, as described above. However, this system does not work properly if air flows directly into the fuel side, and only a combustion reaction occurs. Also, if the electrode/electrolyte/electrode is bent as shown in Figure 5, the fuel
Air leaks out so much that it does not work as a power generation system.

[Problem to be solved by the invention] Due to performance requirements of the solid electrolyte and electrode laminated membrane of a solid electrolyte fuel cell, it is necessary to separate fuel and oxygen (or air) as shown in Figure 4. . Moreover, the solid electrolyte and the electrode are laminated and degreased and fired as a unit before being degreased and fired. At this time, the solid electrolyte and the electrode are warped by about 1000 μm during baking as shown in FIG. 5 due to the difference in shrinkage behavior due to sintering assuming degreasing and the difference in temperature distribution. This warpage causes leakage and makes it difficult to separate the fuel and oxygen (or air).

The present invention was made in view of the above circumstances, and involves heating a laminated film in which a fuel electrode material, a solid electrolyte material, and an oxygen electrode material are laminated and sintered at an appropriate temperature, and applying ZrO through the material to an appropriate temperature. It is an object of the present invention to provide a method for forming a laminated membrane that can reduce the warping of the laminated membrane during combustion by pressing with a surface pressure load, and can prevent performance deterioration of a solid electrolyte fuel cell.

[Means for Solving the Problems] In the present invention, in order to planarize (flatten) the warpage of the laminated film of solid electrolyte and electrodes after firing, the laminated film is heated again to a temperature equal to or lower than the firing temperature while applying a load. At this time, in order to apply a load, in order to prevent a reaction between the material placed on the laminated film and the electrode, a less reactive material is sandwiched, or a less reactive material is used as the material to which the load is applied. In other words, in the present invention, a laminated film in which a fuel electrode material, a solid electrolyte material, and an oxygen electrode material are laminated and sintered is heated from 1100°C to 1250°C and 4 gf/cs2 to 7 gf/cs is heated via the ZrO material.
This is a method for forming a laminated film characterized by pressing with a surface pressure load of c12.

In the present invention, the warpage of the laminated film is T (distance between electrode materials)
-1 (thickness of the laminated film), and smooth as used in the present invention refers to the case where T-t<200 μm.

[Function] Although the laminated film of solid electrolyte and electrode is a material that does not easily deform, deformation occurs when a load is applied at high temperatures. In the present invention, this phenomenon is utilized to flatten the warpage during firing of the laminated film.

Embodiments of the present invention will be described below with reference to the drawings.

[Example 1] Please refer to FIG.

lla in the figure is a porous ZrO2 sheet 12a on the top.
This is the first AJz03 (alumina) plate formed with. Further, Ilb is a second alumina plate on which a porous ZrO2 sheet 12b is formed on the lower part and a weight 13 is placed on the upper part.

In the first embodiment, the first and second alumina plates are arranged so that their sheet surfaces face each other, and the first electrode 14 is placed between these alumina plates. A laminated film consisting of the solid electrolyte 15 and the second electrode 15 was sandwiched, a load was applied with the weight 13, and the film was heated and flattened. Here, the material of the first electrode is NiO, and the thickness Io
It is oam. The material of the solid electrolyte 15 is 85 oi.
1% T2O, stabilized ZrO2, 300 μm thick. The material of the second electrode is L ao, ass r o
, +sM n Os and has a thickness of 100 μm.

According to the first embodiment, the first electrode 14. The laminated film consisting of the solid electrolyte 15 and the second electrode 15 is heated from 1100°C to 1250°C, and at the same time
Since the pressure is applied with a surface pressure load of 4 to 7 gf/cm2 via a and 12b, the warpage of the laminated film can be reduced.

Furthermore, the ZrO2 sheet 12a has low reactivity with the electrode.

Since 12b is brought into contact with the laminated film, no deterioration of the reaction layer or the like occurs in the laminated film.

Table 1 below shows the results of changing the straightening temperature from 3 gf/e2 to 8 gf/c2 with a straightening temperature of 12[10'C1 and a straightening time of 15 hours. When the straightening pressure was low, sufficient straightening was not possible, and when it was high, the laminated film was cracked.

Table 2 below shows that the straightening pressure is 5 g f /cm'
.

The results are shown in which the straightening time was set to 15 hours and the straightening temperature was changed from 1050''C to 1300°C.When the straightening temperature was low, the warp could not be straightened, and when the straightening temperature was high, the laminated film was cracked.

Table 3 below shows the pressure during correction of 5 g f /cs2.
゜The straightening temperature is 1200℃ and the straightening time is 3 hours to 1
The results are shown after changing the time up to 5 hours. When the forcing time was 3 hours, the forcing was not sufficient, and when the forcing time was 4 hours or more, good results were obtained.

[Example 2 See Figure 2.

In Example 2, the first electrode (NiO.

Thickness: 100 μm) 14/Solid electrolyte (8tioD
% Y2O3 stabilization ZrO2, thickness 300 μm)/second electrode (L a o, ssS r 0. +5M n
O3, thickness 100, czm) 15 laminated film, 8 ta
o (1% Y2O3 powder 21 was sandwiched and a pressure of 5 gf/cm2 was applied, heated to 1200 ° C., and held for 15 hours. The warp of the fired body before treatment was 900 μm, but the warp after straightening was 140 μm. Met.

[Example 3] See Figure 3.

In Example 3, the first electrode (N i O, thickness 1
00 μm) 14/solid electrolyte (8mof)% Y2
Stabilization of ZrO2, thickness 300 μm) / second electrode (Lao8.s ro1gMn03, thickness 10 (1
8m)15 laminated films were sandwiched between dense 8mol)% Y2O3 stabilized ZrO2 plates 31, and a pressure of 5gf/cm2 was applied, heated to 1200°C, and held for 15 hours. The warpage of the fired body before treatment was 1100 μm, but the warp after straightening was 160 μm.

[Effects of the Invention] As detailed above, according to the present invention, a laminated film in which a fuel electrode material, a solid electrolyte material, and an oxygen electrode material are laminated and sintered is heated at an appropriate temperature and By pressing with an appropriate surface pressure load, the warping of the laminated membrane during combustion can be reduced, thereby preventing performance deterioration of solid electrolyte fuel cells, and also preventing deterioration of reaction layers etc. in the laminated membrane. It is possible to provide a method for forming.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a method of forming a laminated film according to Example 1 of the present invention, FIG. 2 is an explanatory diagram of a method of forming a laminated film according to Example 2 of the present invention, and FIG. 3 is an explanatory diagram of a method of forming a laminated film according to Example 2 of the present invention. FIG. 4 is a schematic diagram of a fuel cell, and FIG. 5 is a schematic diagram of a fuel cell in which an electrolyte and an electrode are aligned. 11a, llb-Al120 i plate, 12a
, 12b--ZrO2 sheet, l3...weight, 21-Y203 powder, 31-Zr02 plate. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 2 Figure 13 Figure 4

Claims (1)

[Claims] A laminated film in which a fuel electrode material, a solid electrolyte material, and an oxygen electrode material are laminated and sintered is heated from 1100°C to 1250°C and heated at 4 gf/cm^2 to 7 gf/ through a ZrO material.
A method for forming a laminated film, characterized by pressing with a surface pressure load of cm^2.