JPS5846823B2 - Alkaline battery manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an alkaline battery with excellent leakage resistance.

Generally, a button-type alkaline battery is assembled as shown in Fig. 1, in which 1 is a positive electrode can that also serves as a positive electrode terminal, 2 is a positive electrode active material, 3 is a separator group made of appropriate combinations of cellophane, nonwoven fabric, microporous membrane, etc. 4 is a so-called paste-type negative electrode active material made by adding a gelling agent such as CMC to zinc powder, 5 is a negative electrode that also serves as a negative electrode terminal, and is usually made of a clad plate made of stainless steel on the outside and copper on the inside, 6 The cross section is xL
Nylon 6.66 or 12 with molded ring backing
etc. are common materials.

Batteries with such a sealed structure have the disadvantage that they cannot prevent leakage or twisting mainly on the negative electrode side.

In order to improve this, various measures have been taken at the caulking part, such as applying water treatment to the puffer fish, filling the gap between the backing and the can with liquid backing, and integrally molding the can and the backing. Each of these methods has been proposed, and each has achieved a certain degree of effectiveness, but they still have the drawback of not being able to provide a satisfactory level of leakage resistance.

The present invention eliminates the above-mentioned drawbacks, and will be explained in detail below using an example.

Figure 2 shows a battery manufactured by the method of the present invention, in which 1 to 6 are the same members as in Figure 1, except that 7 is an alkali-resistant and hydrophobic insulating coating according to the present invention, and 8 is a hydrophilic gel. It is a layer.

The negative electrode active material of this type of battery is a paste type zinc electrode to which a gelling agent is added as described above.

Since this portion is a place through which ions must pass during discharge, the gel concentration must also be kept relatively low.

On the other hand, since the gel layer 80 portion is not related to discharge performance, there is no problem in forming a gel with as high a viscosity as possible.

In other words, the high viscosity gel is extremely effective in improving the leakage resistance of batteries.

To form such a high viscosity gel, CMC, PV
It may be formed using a normal alkali-resistant gelling agent such as A or sodium polyacrylate and water.Also, as a method of placing the negative electrode active material 4 at a specific location shown in FIG.
It may be injected from a specific nozzle before, during, or at the same time as filling the gel, but it is extremely difficult to inject a viscous gel in a fixed amount in a fixed form, and the rate of defective batteries is high.

For this purpose, a hydrophobic film 7 that is not directly related to leakage resistance is formed in advance, and then a preliminary process of coating and drying a hydrophilic gel is applied to each negative electrode, and the battery assembly is completed. Batteries with excellent leakage resistance can be assembled without making any changes to the main line.

An example in which the manufacturing method of the present invention is applied to a JISG-13 type silver oxide battery is shown in FIG.

Figure 3 shows the negative electrode, which also serves as the battery's negative terminal, with a shape similar to a, with 3 layers of nickel, stainless steel, and copper from the outside.
It is a layered board.

In the first step, after assembling as shown in b, an aliphatic polyamide solution is applied to the portion that should come into contact with the backing and dried to form a thin hydrophobic coating 7.

The role of this coating r is to prevent the hydrophilic gel layer 8 applied in the next step from directly adhering to the outer surface (copper surface) of the lid.

In the second step, as in C, a gel layer 8 of a 40% aqueous solution of PVA is applied and dried.

The coating position is adjacent to the hydrophobic coating 7 in the first step and closer to the inside of the can, but since the outer surface is coated in the first step, there may be some protrusion.

If the lid is manufactured using a normal assembly process using such a pre-treated lid, the dried PVA gel layer 8 on the inside of the negative electrode can will swell again with the electrolyte and become a hydrophilic high-viscosity gel. It forms the

As described above, according to the method of the present invention, it is easy to form a gel layer on each negative electrode, and although the hydrophilic and high viscosity gel layer cannot prevent the permeation of the alkaline electrolyte, it ensures the permeation rate. It is possible to improve the leakage resistance of the battery by reducing the leakage resistance of the battery, and its industrial value is significant.

[Brief explanation of drawings]

Figure 1 is a vertical cross-sectional view of a conventional button-type alkaline battery, Figure 2
The figure is a longitudinal sectional view of a button-type alkaline battery according to the present invention, and FIG. 3 is a manufacturing process diagram according to an embodiment of the present invention. 1... Positive electrode can, 5... Each negative electrode, 6...
...Backing, 7...Insulating coating, 8...
...Gel layer.

Claims (1)

[Claims] 1. After forming an alkali-resistant and hydrophobic insulating coating on the peripheral edge of each negative electrode that contacts the backing and forming a hydrophilic gel layer around the inner surface of each negative electrode adjacent to the insulating coating and drying, the battery element A method for manufacturing an alkaline battery, in which the battery is sealed with a positive electrode can via a backing.