JPS58163168A - Silver oxide cell - Google Patents

Abstract

PURPOSE:To keep down the internal resistance up to being as low as capable of taking in a discharge reaction without making all processes unnecessary for forming a silver layer on a silver oxide surface by the way of preliminary discharge, by containing phosphorous graphite in a sticking layer of manganese dioxide covering the silver oxide. CONSTITUTION:Positive pole black mixture 1 is made up in the following process that silver oxide powder is granulated into 100-300mu or so in advance while a manganese dioxide or about 2-20mu and phosphorous graphite both are mixed with this granulated powder, and at the time of this mixing, each surface of the said silver oxide granule is layered by dint of the moisture absorption and water absorbability of the manganese dioxide. This black mixture is press- molded into the specified thickness by means of a routine process but even after molding, the sticking layer of said manganese dioxide and phosphorous graphite remains kept intact. The amount of the manganese dioxide used is set at 2-7pts.wt. to 100pts.wt. of the silver oxide while the amount of the phosphorous graphite used is set at 0.2-1pts.wt. to 100pts.wt. in total of the silver oxide and the manganese dioxide, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a silver oxide battery in which silver oxide is used as the main anode active material and a small amount of manganese dioxide and phosphorous graphite are added thereto.

In silver oxide batteries, it is common practice to mix a small amount of manganese dioxide or phosphorous graphite with silver oxide as the positive electrode active material. Phosphorous graphite helps with electronic conductivity, and adding manganese dioxide has the advantage of being able to predict battery life in advance due to the potential difference between silver oxide, which has a high discharge voltage, and manganese dioxide, which has a low discharge voltage. be.

By the way, when obtaining such a mixed anode, generally,
A method of mixing silver oxide, manganese dioxide, etc. in powder form and press-molding this is used, but a powder mixture has the disadvantage that it is difficult to mold, and even if it can be molded, it is difficult to provide sufficient strength. Therefore, an attempt was made to make the mixture described in item 1 into granules and subject them to pressure molding, but even with this method, satisfactory moldability could not be obtained. The reason for this is that manganese dioxide itself is porous and easily absorbs water, so even if it is mixed with silver oxide and made into granules, it is difficult to maintain sufficient strength in the granule state due to water absorption. .

As a result of intensive studies from this point of view, the inventors of the present invention did not mix silver oxide, manganese dioxide, and phosphorous graphite in powder form, but first made only silver oxide into granules, and then added finely powdered carbon dioxide. When manganese and phosphorous graphite were mixed, the manganese dioxide and phosphorous graphite adhered to the surface of the granular silver oxide and were easily formed into a layer by moisture absorption, resulting in a granular anode mixture with stable strength. Knowing that this could be the case led us to complete this invention.

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

Figure 1 shows an example of the silver oxide battery of this invention.
1 is an anode mixture, 2 is a cathode agent whose active material is amalgamated zinc powder, 3 is an electrolyte absorber such as vinylon-rayon mixed paper or nonwoven fabric, which is in contact with the cathode agent 2, and 4 is the above absorber. 3 and the anode mixture 1 is a separator made of cellophane and a microporous polypropylene film or a polyethylene graft a composite film.

5 is an anode can made of nickel-plated iron in which an anode mixture 1, a separator 4, and an electrolyte absorber 3 are filled, and the opening of the can 5 is filled with a cathode material 2. The cathode terminal plate 6, which serves as a cathode current collector, is fitted with an annular gasket 7 made of various resins such as nylon, polyethylene, polypropylene, or rubber and having a cross-sectional shape, and the anode can 5 is tightened inward. The inside of the battery has a sealed structure.

The above anode mixture 1 is prepared by adding 100 to 300μ of silver oxide powder in advance.
This is mixed with about 2 to 20 μ of manganese dioxide and phosphorous graphite, and when mixed, due to the hygroscopic and water absorbing properties of manganese dioxide, it is adhered in a layer to the surface of the silver oxide granules. This is pressure-molded to a predetermined thickness by a conventional method, but even after this molding, the adhesion layer of manganese dioxide and phosphorous graphite described in 1. is maintained as it is. -The amount of manganese dioxide to be used is 2 to 7 parts by weight per 100 parts by weight of silver oxide, and the amount of phosphorous graphite to be used is the total fit of silver oxide and manganese dioxide.
The content is set at 0.2 to 1 part by weight per 100 parts by weight.

As described above, in the silver oxide battery of the present invention, since the anode mixture can be formed into granules with sufficient strength, the molding workability is greatly improved, and the silver oxide has a higher oxidizing power than the granules. Because it has a structure coated with weak manganese dioxide, it can suppress oxidative deterioration of the separator, and the manganese dioxide adhesion layers are connected to each other in a chain form, giving good results to the discharge reaction. Due to its liquid absorption properties, effects such as greatly improved heavy load discharge characteristics are brought about.

FIG. 2 shows the heavy load discharge characteristics of the silver oxide battery of the present invention, and shows the test results under a 0.025 Ω load. In the figure, curve 1 is the result of the product of the present invention, and curve 2 is the result of the conventional product related to powder mixture. This shows that the battery of the present invention has excellent discharge performance.

In addition, in the silver oxide battery of this invention, phosphorous graphite is included in the adhesion layer of manganese dioxide coated with silver oxide, so if this graphite is not included, the silver oxide surface is coated with silver by preliminary discharge. Whereas it was necessary to greatly reduce the internal resistance by forming a layer, it is possible to suppress the internal resistance to a low level that can participate in the discharge reaction without requiring any such treatment.

[Brief explanation of the drawing]

Figure 1 shows an example of a silver oxide battery according to the present invention.
') QA surface diagram, FIG. 2 is a characteristic diagram showing the heavy load discharge characteristics of the above battery. 1... Anode mixture. -(6)

Claims (1)

[Claims] (1) A silver oxide battery characterized in that an adhesion layer consisting of particulate manganese dioxide and phosphorous graphite is provided on the surface of granular silver oxide to constitute an anode mixture.