JPS58163151A - Silver oxide cell - Google Patents

Abstract

PURPOSE:To markedly improve the heavy load electric discharge characteristic by constituting the positive electrode black mix from an applied layer made of manganese dioxide on the formed graphite which is formed on the surface of silver oxide in granular form. CONSTITUTION:The positive electrode black mix 1 is prepared by forming the silver oxide powder into granular form having a diameter of 100-300mu and mixing the formed graphite with the above silver oxide powder, and further mixing manganese dioxide having a diameter of 2-20mu and allowing the manganese dioxide, because of its hygroscopic property and water absorbing performance, to be adhered in laminated form onto the surface of the above silver oxide granules. The above compound is compression-shaped to a prescribed thickness by the normal ways. The adhered layer of consisting of formed graphite and manganese dioxide is retained as it even after shaping. 7-70 parts of Manganese dioxide are used for 100 parts of silver oxide by weight, and 0.2-1 part of the formed graphite is used for the total 100 parts of silver oxide and manganese dioxide.

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 small amounts of manganese dioxide and cylindrical 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 in electron conductivity, and adding manganese dioxide provides benefits such as being able to predict the 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. .

By the way, when obtaining such a mixed anode, generally,
A method in which silver oxide, manganese dioxide, and phosphorous graphite are mixed in powder form and then pressure molded.

However, powder mixtures have the disadvantage that they are difficult to mold, and even if they can be molded, it is difficult to provide sufficient strength. Therefore, an attempt was made to make the above mixture 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 and manganese dioxide in powder form, but made only silver oxide into granules without stirring, and first added finely powdered phosphorous graphite. When the phosphorescent graphite and manganese dioxide were deposited on the surface of the granular silver oxide and then mixed with finely powdered manganese dioxide, the phosphorescent graphite and manganese dioxide adhered to the surface of the granular silver oxide in a two-layered structure and were easily formed by moisture absorption. This led to the realization that a granular anode mixture with stable strength could be produced, leading to the completion of 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 separator is interposed between the absorber 3 and the anode mixture 1 and is made of cellophane and a microporous polypropylene film or a polyethylene graft polymer film.

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

The above anode mixture 1 is prepared by adding 100 to 300μ of silver oxide powder in advance.
First, mix phosphorous graphite into the granular form.
After that, about 2 to 20 μm of manganese dioxide is further mixed, and at the time of mixing, manganese dioxide is attached in a layered manner to the surface of the silver oxide granules due to its hygroscopic and water absorbing properties. Pressure molding is performed to a certain thickness, but even after this molding, the adhesion layer of the phosphorous graphite and manganese dioxide is maintained as it is. The amount of manganese dioxide used is 2 to 7 parts by weight per 100 parts by weight of silver oxide, and the amount of phosphorous graphite used is 0.2 to 1 part by weight per 100 parts by weight of the total amount of silver oxide and manganese dioxide. In the department,
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 Since it is coated with manganese dioxide, which has a weaker oxidizing power than this, it can suppress oxidative deterioration of the separator, and the manganese dioxide deposited layers are connected to each other in a chain form, giving good results to the discharge reaction. Due to its moisture and liquid absorbing properties, it brings about effects such as significantly improved heavy load discharge characteristics.

FIG. 2 shows the above-mentioned heavy load discharge characteristics of the silver oxide battery of the present invention, and shows the test results under a 0025Ω load. In the figure, curve-1 is the result for the product of the present invention, and curve-2 is the result for the conventional product. This shows that the battery of the present invention has excellent discharge performance.

Further, the silver oxide battery of the present invention uses phosphorous graphite together with manganese dioxide, and the phosphorous graphite is independently attached to the granular silver oxide, and a manganese dioxide adhesion layer is provided thereon. Therefore, it is possible to exhibit the original electronic conductivity of phosphorous graphite well, while also fully exhibiting the above-mentioned performance of manganese dioxide as a surface adhesion layer. Regarding the electronic conductivity of phosphorous graphite, if an adhesion layer consisting only of manganese dioxide is provided without using phosphorous graphite at all, the internal resistance of the battery will increase significantly. It becomes necessary to form a conductive silver layer on the silver oxide surface by performing the following steps. However, in the present invention, which uses phosphorous graphite as described above, such concerns do not arise at all.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of the silver oxide battery of the present invention, and FIG. 2 is a characteristic diagram showing the heavy load discharge characteristics of the battery. 1... Anode mixture.

Claims (1)

[Claims] il+ A silver oxide battery characterized in that an anode mixture is formed by providing an adhesion layer of fine particulate phosphor graphite on the surface of granular silver oxide and further comprising manganese dioxide thereon.