JPS6013266B2 - Manufacturing method of silver oxide battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the improvement of a silver oxide battery using silver oxide (Ag20) as an active material in the intestinal electrode and an alkaline solution as an electrolyte, and aims to improve the discharge performance. This is the main purpose.

This type of battery suffered from significant performance deterioration during storage.

As a result of various studies on this performance deterioration, the inventors found that
It was discovered that conductive agents made of carbonaceous materials, such as phosphorous graphite, acetylene black, and activated carbon, added to the anode accelerate the decomposition of ferrous oxide, leading to performance deterioration. That is, when the first line of oxidation and carbonaceous material come into direct contact in an alkaline electrolyte, the reaction described below occurs, and the first silver oxide is reduced to metallic silver, depolarizing ability is reduced, and carbon dioxide gas is generated.

Key 200C → 4Ag+C02 Also, the generated carbon dioxide reacts with the alkaline electrolyte to produce carbonate, which reduces the ionic conductivity of the electrolyte and further promotes passivation of the cathode active material, resulting in cooling the sex room. bring about change.

In order to eliminate the negative effects of carbonaceous materials mentioned above, attempts have been made to add metallic silver or metallic silver vapor-deposited onto the carbonaceous surface as a conductive agent, but when these additions are added, the formability of the anode is poor. In particular, when the molded anode is removed from the mold, it may collapse or chip, reducing workability and increasing the dispersion in the performance of each battery.

The present invention does not contain a conductive agent made of carbonaceous material such as phosphorous graphite, or the amount of such conductive agent added is small.
Impregnating a molded anode mainly composed of silver oxide with water or a liquid mainly composed of water, and bringing the anode into contact with a reducing solution or gas to form a metallic silver layer on the surface of the anode,
By bringing the metallic silver layer into contact with the anode terminal member,
This eliminates the aforementioned drawbacks.

By not containing conductive agents made of carbonaceous materials as mentioned above, or by reducing the amount of these conductive agents added,
Although the decomposition of ferrous oxide can be effectively suppressed, since ferrous oxide has extremely low conductivity, the contact resistance between the anode and the anode terminal member increases, especially when the predetermined terminal voltage is low at the beginning of discharge. I can't get it.

The discharge of the anode gradually progresses from its surface to the inside, and metallic silver is generated by the discharge, and this metallic silver can be used as a conductive agent that promotes the discharge reaction of the anode. If a metallic silver layer is formed in advance, a predetermined stable terminal voltage can be maintained throughout the entire discharge process without adding a conductive agent inside the anode.

As a means of forming a metallic silver layer on the surface of the anode, the inner surface of the anode can is plated with a reducing metal, such as zinc or cadmium, which contacts the oxidized first coin and reduces it to metallic silver.
There is a method of inserting an anode into this and bringing it into contact with a reducing metal to form a metallic silver layer on the anode surface, or a method of pre-discharging the battery after incorporating the {B' anode into the battery and forming a metallic silver layer on the anode surface. We tried methods such as forming a .

However, with the sail method, when plating the inner surface of the anode can using the gala plating method used in mass production, it is difficult to plate the inner surface of the anode can with a specified thickness, especially on the inner surface of the bottom of the anode can that comes into contact with the anode. Stable battery performance cannot be obtained due to variations in the temperature of the anode, and when zinc or other plating is applied from the end of the anode can to the bottom of the can, a local battery is formed between the anode and the plating layer that does not come into contact with the anode. As the discharge of the plating layer progresses, the electrolyte flows through the plating layer,
Liquid leaks from the open □ end of the anode can.

In the leg method, the cathode is also consumed by the preliminary discharge, which reduces the discharge capacity of the battery, which is not preferable. The present invention employs a method that does not cause such drawbacks, that is, a method in which the anode is brought into contact with a reducing agent solution or a reducing gas to partially reduce the anode surface to form a metallic silver layer.

However, since these reducing agents are in a liquid or gaseous state, they penetrate into the interior of the anode and excess ferrous oxide is reduced, resulting in a decrease in discharge capacity and variations in performance. Therefore, in the present invention, the anode molded body is impregnated with water, or a suspension of polyolefin, fluororesin, etc.
Alternatively, by impregnating a liquid mainly composed of water, such as a dilute solution of water glass, and performing a reduction treatment in this state, the interior of the anode can be prevented from being excessively reduced, and a thin metallic silver layer can be applied to the anode surface. It was formed. In the present invention, the anode is made by press-molding ferrous oxide powder alone without containing a conductive agent made of carbon such as phosphorous graphite. Anode made by pressure molding a mixture of ferrous silver, manganese dioxide (in addition to ferrous oxide),
An anode containing a small amount of an active material such as Mh02) or nickel hydroxide (Ni00H) is used.

Adding h-02 or Ni00 to the anode has the advantage of alleviating the temporary voltage drop that occurs immediately after the start of discharge, particularly during heavy-load discharge. The reducing agent solution used in the present invention includes hydrazone, hydrazine, ammonia, urea, formalin, sodium thiosulfate, etc., and the reducing gas includes nitrogen gas containing hydrogen gas.

Among reducing agent solutions, formalin, sodium thione sulfate, etc. may leave carboxylic acid and sodium sulfate in the anode after reduction, and there is a concern that this may adversely affect electrode performance. is suitable. Next, examples of the present invention will be described.

Example 1 Without containing a conductive agent made of carbonaceous material such as phosphorous graphite,
Fine particle ferrous oxide having a particle size of about 0.1 to 5 peaks is used alone, and this is pressure-molded at a pressure of about 5 n/base to form anode 1.
Create.

Next, the anode 1 is impregnated with water and immersed in a hydrazone solution maintained at about 60 to 80 qO for about 30 minutes to reduce the surface of the anode 1 and form a metallic silver layer 2.

Example 2 The anode 1 was impregnated with water in the same manner as in Example 1, and the anode 1 was left for about 5 minutes in a stream of nitrogen gas containing 5% hydrogen gas maintained at about 50 to 70°C. Then, a metallic silver layer 2 is formed on the surface of the anode 1.

The drawing shows a silver oxide battery according to the present invention, in which an anode 1 with a metal silver layer 2 formed on its surface is inserted into the bottom of an anode can 3 which also serves as an anode terminal, and a cellophane layer is placed on top of the anode 1. A separator 4 made of the above-mentioned material and an absorbent paper 5 made of a mixed paper made of vinylon and vinylon are sequentially layered. An L-shaped gasket 6 made of synthetic resin and a cathode terminal plate 8 containing a cathode material 7 made of a mixture of zinc powder and gelled alkaline electrolyte are iron-bonded to the entrance of the anode can 3. Curl the open end of the battery inward to seal the battery. Silver oxide battery C using the anode of Example 1, Silver oxide battery ○ using the anode of Example 2, Anode constructed using silver oxide powder alone and impregnated with water. An oxidized first-line battery E was used, which was immersed in a hydrazone solution without being exposed to water to form a metallic silver layer on the surface. The range of variation in discharge duration at the initial stage of production when each of the oxidized 1-sen batteries F was discharged at IKQ, and
The following table shows the variation range of discharge duration when discharged under the same conditions after storage at 60℃ for 20 days.

As is clear from this table, the silver oxide batteries C and D according to the present invention show little performance deterioration during storage, and
It has little roughness and stable discharge performance.

BRIEF DESCRIPTION OF THE DRAWINGS The drawing is a cross-sectional view of a silver oxide battery according to the present invention. 1...Anode, 2...Metal silver layer, 3...
...Anode can.

Claims (1)

[Claims] 1 Impregnating water or a liquid mainly composed of water into an anode molded body mainly composed of ferrous oxide, which does not contain a conductive agent made of carbonaceous material such as phosphorous graphite, or has a reduced amount of such a conductive agent, A method for manufacturing a silver oxide battery, which comprises bringing the anode into contact with a reducing agent solution or reducing gas to form a metallic silver layer on the surface of the anode, and bringing the metallic silver layer into contact with an anode terminal member.