JPS5827051A - Manufacture of oxygen gas concentration cell - Google Patents

Abstract

PURPOSE:To obtain an O2 gas concentration cell which is excellent in durability, by a method wherein, after a plural number of pairs of electrodes and connecting leads are printed on the surfaces and the backs of two raw sheets, insulating oxide slurry is applied on an outer surface of a tubular body, and after an intermediate sheet, nipped by said two sheets, is heated and pressed, the work is sintered. CONSTITUTION:A plural number of pairs of electrodes for cell 45-49, 45'-49', connecting leads 35-38, 35'-39', 40-44, 40'-44', connecting leads 30-33, 30'- 33', are screen-printed on their respective surfaces and backs of raw sheets 1-A, 1-B containing solid electrolyte powder stabilized by Y2O3. Then, after slurry, containing insulating oxide powder, magnesia spinel, and the same binder as that of the raw sheets 1-A, 1-B, is screen-printed on a surface where the electrodes 40-44, 45-49 are formed, said two sheets are overlapped with each other with a framed raw sheet 1 between. After the work is spressed, it is sintered at high temperature to obtain a hollow flat tubular O2 concentration cell. This enables improving of durability to car exhaust gas and lengthening of a cell life.

Description

[Detailed description of the invention] The present invention uses a solid electrolyte having oxygen ion conductivity to
The present invention relates to a method of manufacturing an oxygen gas concentration battery element.

Oxygen gas concentration cells using solid electrolytes such as zirconia are widely used as fuel cells or oxygen concentration meters for industrial measurement control and automobile exhaust gas control.

The present inventors previously disclosed a solid electrolyte powder and a thermoplastic resin organic binder in Japanese Patent Application No. 56-34808.

We also proposed a method in which electrodes are formed using a screen printing method on green sheets containing an organic plasticizer, and a plurality of these green sheets are glued together and fired to produce a hollow cylindrical oxygen gas concentration cell body.

The oxygen gas concentration cell body obtained by this process not only has a stable output because it has a small internal resistance and the accuracy of electrode formation is increased.

It has an excellent feature in that it has a structure in which single cells can be easily integrated through a relatively simple process.

Figure 1 (ta) (1)) is a plan view showing an example of the oxygen gas concentration cell body obtained in this way, and a sectional view taken along the line A-A. (3
1 (30', 31'...), and (35°36
......) is the lead, (41 (40, 41...
...) are electrodes, (5) (5a, 5b) are terminal leads, (61 (80, 61...) are small holes for connection,
(7) is a small hole for connecting the upper and lower cell groups of the hollow simple body. This example shows a case where 10 cells are connected in series.

Oxygen gas for detecting oxygen concentration in automobile exhaust gas (02)
Considering the case where it is used as a sensor element.

Since the inside of the element body is used as an air reference electrode (electrode), there is no problem with the corrosion resistance of the electrode, but the outer electrode (-
(pole) is exposed to the redox atmosphere of exhaust gas at high temperatures, so corrosion resistance becomes a problem. Conventionally 1.02 of such well-known uses
In the sensor, an insulating oxide powder such as magnesia spinel or alumina is applied to the outer surface of a solid electrolyte element such as ZRO2 on which electrodes are formed to a desired thickness by plasma spraying to form a protective film layer for the electrodes. Ta.

This method is usually carried out in the final step of manufacturing the device.

The present invention utilizes to the fullest the flatness of the hollow cylinder obtained by the method of integrating single cells into one element as described above. 4, which makes it possible to provide a method for manufacturing an oxygen gas concentration battery, which is characterized by a simplified manufacturing method.

Hereinafter, the present invention will be explained in detail according to examples.

Example 1 A green sheet (1-
A) Multiple pairs of battery platinum electrodes (4) and platinum lead parts (3) are formed on the front and back surfaces of (1-0) by screen printing, and small holes (61 (60 ,6
Apply platinum paste to 1...) and connect the batteries in series. The raw sheet obtained by the above method is the second
(1-A) (1-B) shown in the top view (a) and side view (b) of FIG.

In the figure, (2) is the reference hole, (31 (30, 31...
...and 3 G', 31'...) are lead parts, +41 (40.

41-..., 40', 41'-, -) are electrodes, (5a) and (5b) are terminal leads, and (6) and ()) are small holes for connection.

Next, the raw seam in Figure 2) (the surface of 1-A (electrode (45)
~ (49) side), and raw sea in Figure 3) (1-B
) (magnesia spinel with an average particle size of 5 μm and a thermoplastic organic binder having the same composition as when forming the green sheet so as to leave some additional terminal lead parts on the electrodes (40) to (44) side, and A paste containing an organic plasticizer was printed to a thickness of about 50 μm on the terminal leads (5a) and (5b) except for a portion using a screen printing method, as shown in FIG.

This is shown by the shaded area (8) in FIG.

Next, prepare an intermediate raw sheet (1-0) that facilitates the formation of a hollow cylinder as shown in the plan view and perspective view of FIG. Electrode (40) ~
(corresponding to the (44) side). Next, stack the raw sheet (1-A) shown in Figure 2 on top (electrodes (45) to (49) sides are on top) and stack the ends. They were bonded together under heat and pressure to obtain a hollow cylinder.

After that, apply the same platinum paste as above to the small hole (7))
The battery connections of the upper and lower raw sheets (1-A) and (1-B) were performed in detail. After that, this inner wall cylinder is fired under the conditions of 1@50' for 0.5 hours, and unnecessary parts are removed to form a cylinder as shown in Fig. 1, which has an oxide protective film (not shown) on the outer surface. Ten batteries were assembled in series (~) to obtain an element body for an oxygen gas concentration battery.

According to this method, the formation of an oxide film for protecting the electrodes can be carried out with high precision using the same simple method as the method of printing electrodes on green sheets, and the baking of the oxide can be carried out at the same time as the firing of the hollow simple body. It has the characteristic that it is omitted.

In addition, in the above method, since there is no protective film layer on the part where the wire is connected through the small hole (7), the oxide film can be applied to this part by himself.

In the above embodiment, K, which is caused by connecting all the batteries in series and which makes this work unnecessary, is a pair of raw sheets (1-A) as shown in the perspective views of FIGS. 5 and 6. (1-B)
In order to enable parallel connection of the upper and lower battery groups of the K medium 9 simple body, the leads (35') and (30') may be provided in advance to extend toward the open end of the hollow simple body. .

It goes without saying that the oxide protective film layer needs to be porous on the electrode surface. Further, it is desirable from the viewpoint of improving the adhesion of the protective film that the composition of the organic thermoplastic binder and the organic binder used during printing be the same as in the case of forming the ceramic green sheet. In addition, in this case, the combination of the oxide powder and the organic binder is such that the amount of the organic binder is increased by at least 30% compared to the case where a raw sheet is made from the solid electrolyte powder and the organic binder. It is preferable to obtain it stably, and it is also convenient to select an oxide powder having a particle size of 5 μm to 10 μm. If gas leakage from the element is a problem, after sintering the hollow simple body, if necessary, the softening temperature should be 1000°0 in the small hole where the battery was connected, its vicinity, and the area where the element was laminated.
It is possible to apply a certain amount of glass to soften and fluidize it to improve gas pressure resistance. However, it goes without saying that this work requires a glass composition and heat treatment conditions that suppress the reaction between the ZR02 element, which is a solid electrolyte, and the glass as much as possible. Furthermore, it is also necessary to take care that the protective film layer does not become airtight on the electrode surface during this heat treatment as described above.

As described above, according to the method for manufacturing an oxygen gas concentration battery of the present invention, after electrodes are formed on a phantom sheet by a screen printing method, a hollow simple oxide protective film layer can be formed by the same method. It has excellent features such as being extremely simple and allowing precise control of the thickness of the protective film layer.

Its industrial value is great.

[Brief explanation of drawings]

FIG. 1(a) (1)l is a plan view and a sectional view taken along the line A-A of a hollow simple oxygen gas concentration battery. FIGS. 2, 3, and 4 are a plan view and a side view of a raw sheet to illustrate the manufacturing method of the present invention. FIGS. 5 and 6 are perspective views of a pair of raw sheets to show another embodiment of the present invention. In the figure, (11(1-A, 1-B, l
-C! ) is the raw sheet, +21 is the reference hole, (31 (3
0, 31... and 3G', 31'...
)ti lead, (41(40,41...40'
, 41'-...) are electrodes, (5a), (
5b) is the terminal lead (61, (7) is the small hole for connection, (8
) is an oxide protective film. Note that the same numbers and symbols indicate corresponding parts. Agent Makoto Kuzuno - Figure Hakubiyo I,! J-(in'11::&:no history) (b) 1ゝρ Procedural amendment (method) % formula % “29 Name of invention Method for manufacturing oxygen gas concentration battery 3, person making the amendment Representative Hitoshi Katayama Inside Mitsubishi Electric Corporation 6. Specification and drawings subject to amendment. 7. Contents of amendment #1 Detailed review and reprint of drawings (no change in content).

Claims (2)

[Claims] (1) Raw sheets of desired shape and desired thickness containing solid electrolyte ceramic powder, thermoplastic organic binder, and organic plasticizer) (1-A) and (1-B) for multiple pairs of batteries on the front and back surfaces, respectively. A step of forming electrodes and lead portions by screen printing, a step of connecting the battery electrodes in series, and an intermediate green sheet (1-A) (1-B) 1-0) are inserted and laminated, and the ends are heated and bonded together under pressure to create a hollow simple body.
1-A) and (1-B), in which the surface of the raw sheet (1-A) and the raw sheet (1-B) are wired in series or in parallel.
) to the parts other than the terminal leads on the back side of the raw sheet, apply a slurry of an appropriate viscosity containing an insulating oxide powder such as magnesia spinel, a thermoplastic organic binder and an organic plasticizer with the same composition as above to create an electrode on the green sheet. 1. A method for manufacturing an oxygen gas concentration battery, which comprises printing by a screen printing method, which is the same method as above, and heating and sintering at a high temperature. (2) After connecting the end leads of the raw sheets (1-A) and (1-B) in series, apply the same insulating oxide powder paste as above to the connected parts and their peripheral edges. The method for manufacturing an oxygen gas concentration battery according to claim 1, further comprising an additional step.