JPS58165255A - Method of manufacturing silver oxide battery - Google Patents

Abstract

PURPOSE:To provide a battery of high discharge performance, by inserting a molded anode together with an anode ring into a case and compressing the peripheral part of the anode to tightly fit it in the case but leave an uncompressed part in the center of the anode. CONSTITUTION:To manufacture a molded anode 1, powder of AgO is molded and then dipped in a reducing solution so that a silver layer 4 is provided on the surface of the molded powder. The cylindrical part of a ring 2 is inserted in between the anode 1 and an inside wall. An upper die 5 for tightly fitting the molded anode 1 in a case 3 has a columnar shape. The central part of the face of the die 5 has a circular recess 5a of D in diameter and d in depth. The diameter D is smaller than that of a hole 2a. When the anode 1 is pressed, its peripheral part is compressed but its other part corresponding to the recess 5a of the die 5 remains substantially uncompressed. At the same time, the anode ring 2 is pressed into the anode 1. Since the silver layer 4a of the uncompressed part keeps an original porous structure, an electrolyte poured into the part in the following process is quickly absorbed into the anode 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The invention relates to a method for manufacturing a silver oxide battery using divalent silver oxide (MUGO).

If a molded body of MugO is used as a positive electrode as it is, the discharge pressure will be 2.
By forming a silver layer on the surface of the molded body, for example, by reduction treatment, monovalent silver oxide (mugzo) can be added.
A method is adopted to obtain a discharge voltage equivalent to that of the battery used.

'Also, in order to collect current from the positive electrode and to strengthen the battery when sealing the battery, a positive electrode ring with an inverted cross-section is used that covers the positive electrode from the side to the upper periphery. The positive electrode molded body and the positive electrode ring are fully inserted into the mold, and the positive electrode ring is embedded in the positive electrode by applying 7111 pressure to the mold, and the positive electrode is crimped to the case.Then, the electrolytic solution is poured into the upper surface of the positive electrode. Assemble. In this case, since the mold for fully pressurizing the positive electrode is cylindrical with a flat tip, the surface of the positive electrode exposed in the hole of the positive ring is pressurized.
A porous silver layer formed on the surface is compressed to a high density,
Therefore, the ability of the positive electrode to absorb electrolyte is significantly reduced, resulting in an increase in internal resistance and a decrease in discharge performance.

The present invention eliminates the above-mentioned disadvantages and provides a method for obtaining a n* silver oxide battery with excellent discharge performance.

Hereinafter, the present invention will be described in detail with reference to drawings showing embodiments.

FIG. 1 shows a state in which a positive electrode molded body 1 and a positive electrode ring 2 having an inverted cross section are inserted into a positive electrode case a.

The positive electrode molded body 1 is obtained by molding Mu powder and then immersing it in a reducing solution to form a silver layer 4 on the surface. Make it as big as possible.

Figure 2 shows the positive electrode molded body '1 together with the positive electrode ring 2.
7゜BE t,fy'J 7゜ゎゎゎInsert into □ 7゜BE t, fy'J, and press ゛1 to the case 3.
: It is an eyelid mold. The mold 6 has a cylindrical shape and has a circular recess 6a having a diameter and a depth d at the center of its tip surface, and the diameter is smaller than the diameter of the hole 2a in the upper part of the positive electrode ring 2.

When the molded body 1 in the case is pressurized together with the positive electrode ring 2 by this mold 6, the molded body 1 is pressed into the mold 6 as shown in FIG.
Although the portion corresponding to the concave portion 5a is substantially uncompressed, the peripheral portion is compressed, and at the same time, the positive electrode ring 2 bites into the molded body 1.

As described above, the present invention is characterized in that the positive electrode molded body inserted into the case together with the positive electrode ring is crimped to the case by pressurizing and compressing its peripheral edge, leaving an uncompressed part in the center. That is.

By using this method, the silver layer 41L in the uncompressed part retains its original porous structure, so the electrolyte injected into this part in the next step is quickly absorbed into the inside of the positive electrode. Runo Sewashuru.

Conventionally, a mold with a smooth front surface was used, so the whole surface of the positive electrode molded body was compressed. Therefore, the porous structure of the silver layer on the surface was lost, and the absorption of the electrolyte was slow, and the required However, if the present invention is applied, such problems can be easily solved.

Regarding the positive electrode pressurizing mold 6, if the depth d of the recess 51L is too shallow, the center of the positive electrode will be compressed, and if it is too deep, the pressure applied to the peripheral edge of the positive electrode will cause the center of the positive electrode to collapse into the recess 6a. It protrudes inward and causes cracking of the positive electrode. Therefore, it is best to reduce the thickness of the peripheral edge of the dIri positive electrode by compressing it under pressure, which is 1 m! lI may be slightly smaller.

The diameter of the recess 6a is preferably smaller than the inner diameter of the hole in the positive electrode ring 2. If it is equal to or larger than the inner diameter of the hole in the positive electrode ring 2,
The pressurization causes cracks in the positive electrode portion near the edge of the hole in the ring 2, particularly in the silver layer on the surface. As a result of testing various values of D, it was found that the opening area of the recess 6a is preferably 90% or less of the area of the hole in the ring 2. Furthermore, if the opening area of the four parts is made smaller, the uncompressed part becomes smaller, and the liquid absorption force of the positive electrode decreases. Therefore, about 60% of the hole area of the lower limit kneading is suitable. Note that the opening side of the fourth part 6a should be tapered as shown in the figure, but it is better to make it rounded. In the above example, a silver layer is provided on the entire surface of the positive electrode, but as already known, If an insulating layer is provided on the bottom of the positive electrode case, or an insulating layer is formed on the bottom of the positive electrode, a silver layer may be provided only on the sides and top surface of the positive electrode.

Next, diameter 9.5111. Test results for a button-shaped silver oxide battery with a height equivalent to 2.0mm will be explained.

First, a 0.29f mixture powder mainly consisting of MugO was put into a molding mold with n1 total pressure of 2 tons to make pellets.
'Immerse in a methanol solution of hydrazine hittride,
A reduced silver layer with a thickness of about 70 μm was formed on the entire surface.

This pellet was inserted into the positive electrode case along with the entire positive electrode ring, and was applied at a total pressure of 3 tons using a mold in which the depth d of the recess 6a was 5 tar, and the opening area was 80% of the hole area of the ring. Compressed. The entire positive electrode half cell made in this way was compressed using a mold that did not have the recess 51L'i.
Let it be B.

10 μl of a 7 mol/l aqueous solution of caustic potassium was dropped approximately at the center of each of these positive electrodes, and after standing for 30 minutes, the solution remaining on the surface of the positive electrode was absorbed to determine the amount of liquid absorbed into the positive electrode.

As a result, the liquid absorption amount of Mu was 3.4 capes, and that of B was 1.6 capes.

Thus, it is clear that the difference in the amount of electrolyte absorbed into the positive electrode has a significant effect on the discharge characteristics of this type of small battery, especially on the sustaining voltage of high rate pulse discharge under low temperature operating conditions. It has a big impact.

Next, using the above positive electrode half cell B' (17), 10 each of the batteries As b' as shown in FIG. 4 were fabricated.

In the figure, 6 is a separator made of a polyethylene graft polymer membrane and cellophane V, 7 is a liquid-containing material made of nonwoven fabric, 8 is a negative electrode made of an alkaline electrolyte in which zinc oxide is saturated, frozen zinc, and a gelling agent. 9 is a sealing plate, and 10 is a nylon gasket.

Batteries a and b' (at H-10°C, with a load of Ω on 2, pulse discharge with 6 seconds of discharge and 6 seconds of rest) are compared, and the following table shows the average lowest value of the sustaining voltage Ta.

It is clear from the table that the amount of electrolyte absorbed by the positive electrode greatly affects the sustaining voltage of high-rate pulse discharge at low temperatures. This result was shown in the initial performance of the battery, but after storage at 60° C. for 40 days, the deterioration in performance became even greater.

In addition, in the above positive electrode half cell, the ratio n when the positive electrode is pressurized is
However, when the depth of the concave portion of the mold was set to 0.09 MM, the percentage n occurrence rate of the silver layer on the surface of the positive electrode reached approximately 86 mm.

In this case, the depth of the recess, O,OS, is reduced by the thickness reduction due to the pressurization of the negative electrode edge, KNfit6° □ 1 As described above, the present invention makes it possible to create a silver oxide battery with excellent performance. Obtainable.

[Brief explanation of the drawing]

Figure 1 is a longitudinal sectional view showing the positive electrode molded body and the positive ring inserted into the positive electrode case, Figure 2 is a side view with main parts of the positive electrode pressurizing mold cut away, and Figure 3 is after pressurization. FIG. 4 is a longitudinal cross-sectional view showing a positive electrode half cell, and FIG. 4 is a side view showing a main part of the silver oxide battery in cross section. 1...Positive electrode molded body, 2...Positive electrode ring, 3...Positive electrode case, 4...Silver layer, 6
······Mold. Name of agent: Patent attorney Toshio Nakao 1 person vs.
1 Figure 1112 Figure 7

Claims (3)

[Claims] (1) Mug with a silver layer formed on at least the side and top surfaces
By inserting a positive electrode molded body mainly consisting of O and a positive electrode ring having an inverted cross-section into the positive electrode case, and compressing the peripheral part of the positive electrode molded body together with the positive electrode ring, an uncompressed part is created in the center. A method for producing a silver oxide battery, comprising: fixing a positive electrode molded body having a positive electrode molded body to a positive electrode case; and then injecting an electrolyte into an uncompressed part at the center of the positive electrode molded body. (2) The oxidation method according to claim 1, wherein the mold for pressurizing and compressing the positive electrode molded body has four parts in the center having a depth equivalent to the thickness reduced by the pressure and compression of the positive electrode molded body. Method of manufacturing silver batteries. (3) The method for manufacturing a silver oxide battery according to claim 2, wherein the opening area of the recess in the mold is 60 to 90% of the area of the hole in the positive electrode ring.