JPS59101772A - Silver oxide battery - Google Patents

Abstract

PURPOSE:To effectively suppress closed circuit voltage drop accompanying discharge reaction and improve discharge performance by containing fluorine oil in a cathode mix comprising Ag2O as an active material. CONSTITUTION:In a silver oxide battery, fluorine oil such as polytrifluorochloroethylene which is liquid at room temperature is contained in a cathode mix comprising Ag2O as an active material. The fluorine oil is adsorbed in voids of the mix and prevents transfer of alkaline electrolyte into the mix and closed circuit voltage drop caused by lack of alkaline electrolyte accompanying discharge reaction is effectively suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention discloses the use of silver oxide as an anode active material and carbon powder as a mold release agent. The battery is manufactured using a method in which a molded anode mixture obtained by pressure molding is stored inside the battery, but as the discharge reaction progresses, an excessive amount of alkaline electrolyte migrates into the mixture, causing problems in the separator section. There was a problem that the alkaline electrolyte was insufficient and the closed circuit voltage decreased accordingly.

This invention aims to avoid the above-mentioned problems, and its gist is to provide a silver oxide battery characterized in that a fluorine oil is contained in an anode mixture containing ferrous oxide as an active material. be. When fluorine oil is included in the anode mixture, it adsorbs and maintains the internal pressure in the pores of the mixture and prevents the alkaline electrolyte from migrating into the mixture, which is effective in reducing the closed circuit voltage as the discharge reaction progresses. can be suppressed.

A typical example of fluorinated oil is polytrifluorochloroethylene, which has a low degree of polymerization and is liquid at room temperature. Other fluorine oils that exhibit properties similar to those described above can be used. Since such fluorine oil has superior oxidation resistance and alkali resistance compared to silicone oil and the like, there is no concern that it will adversely affect battery reactions.

The method for incorporating fluorine oil into the anode mixture is arbitrary, and any suitable method can be employed, such as filling the mixture by vacuum impregnation after forming the mixture, or kneading it with ferrous oxide during forming the mixture. The content is from 0.5 to the entire anode mixture.
It may be within the range of 5% by weight.

EXAMPLES Below, examples of the present invention will be described in more detail.

Example 5 5 tons/c of 260 cm of silver oxide containing % by weight of graphite
A molded anode mixture with a diameter of 9 mm and a thickness of 0.7 m was formed by pressure molding at +11°C, and this was placed in fluorine oil (trade name Daifloil #3, manufactured by Daikin Industries, Ltd.; low polymerization degree polytrifluoromonochloroethylene). The above-mentioned oil was filled and held in the mixture cavity by vacuum impregnation. Using this mixture, a button-shaped silver oxide battery as shown in the figure was produced by the following method.

That is, the anode can 2 into which a part of alkaline electrolyte is injected
The above-mentioned molded anode mixture 1 was inserted into the mold, and the separator 3 and the electrolyte absorber 4 were sequentially placed on the mixture 1.

Next, the anode can 2 in this state is fitted with an annular gasket 7 around its periphery, and a cathode terminal containing a cathode 6 having 75η of amalgamated zinc as an active material and an alkaline electrolyte with most of the remainder inside. By fitting into the plate 5, tightening and bending the opening of the anode can 2 inward, and sealing the anode can by pressing the inner circumferential surface against the annular gasket 7, a button-shaped body having the configuration shown in the figure is formed. A silver oxide battery was fabricated.

The anode can 2 used was made of iron with a nickel-plated surface, and the cathode terminal plate 5 was made of a copper-stainless steel-nickel clad plate. As the separator 3, a composite membrane is used in which two graft films (graft films made by graft polymerizing methacrylic acid to a cross-linked low-density polyethylene film) are laminated on both sides of cellophane, and the electrolyte absorber 4 is made of polypropylene nonwoven fabric. . As an alkaline electrolyte, 25 in which zinc oxide is dissolved is used.
The weight percent caustic soda water solubility number was used. Also, the battery (button type) has a diameter of 9.5 rum and a height of 2.7 mm.

In order to investigate the performance of this silver oxide battery, we investigated the closed circuit voltage after 2Ω-5 seconds of discharge (-10°C) as the discharge reaction progressed, and the results were as follows. . In addition, the following comparative example is the result of a silver oxide battery produced in exactly the same manner as the example except that fluorine oil was not impregnated.

Depth of discharge Example product Comparative example product Initial stage 1.4
6 V 1.48 V40% 1.43 V
1.32 V2Ochi 1.40 V
1.25 V As is clear from the above results,
It can be seen that the silver oxide battery of the present invention exhibits a small decrease in closed-circuit voltage as the discharge reaction progresses, and has good discharge characteristics.

[Brief explanation of the drawing]

The drawing is a sectional view showing an example of the silver oxide battery of the present invention. 1... Anode mixture. Patent applicant Hitachi Maxell, Ltd.

Claims (1)

[Claims] fl) A silver oxide battery characterized by containing fluorine oil in an anode mixture containing ferrous oxide as an active material.