JPS5887756A - Button type battery - Google Patents

Abstract

PURPOSE:To obtain a battery having high capacity and good leakproofness by applying a sealant comprising a synthetic resin containing 5-20wt% zinc salts or copper salts in a contact area of the end portion of a negative sealing plate with an insulating gasket. CONSTITUTION:For example, 10wt% zinc perchlorate is added to a sealant which is made by dissolving chlorosulfonated polyethylene in toluene. When this sealant is used, if an alakline electrolyte is penetrated between the sealant and a negative sealing plate, zinc is quickly dissolved from the sealant and deposited to prevent gas evolution.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in the sealing structure of a button-type battery, and an object of the present invention is to provide a battery with high capacity and good leakage resistance.

Since primary batteries generally have limited outer diameter dimensions, improvements in discharge capacity are considered by changing the shape of the components to maximize the internal volume. The figure shows an air-zinc button cell as an example. The structure shown in FIG. 1 improves the discharge capacity by 20 to 30% compared to the conventional structure shown in FIG. 2, but this is caused by the difference in shape between the negative electrode sealing plates 3 and 3'. That is,
The one in Figure 1 does not have a bent part around the sealing plate, and the second
The one in the figure has a 3° outward and upward bend at the periphery, and this difference in shape gives the battery internal volume a difference in size.

In recent years, the structure shown in FIG. 1 has been attracting attention as a method of increasing the volume of the negative electrode sealing plate as much as possible as a means of improving the performance and capacity of batteries. In a battery using an alkaline electrolyte, the material of the negative electrode sealing plate 3 shown in FIG. 1 is a three-layer cladding material of nickel-stainless steel nl-copper from the outside. Although the structure shown in Figure 1 allows the internal volume to be expanded, it is a silver oxide battery.

In batteries that use an alkaline electrolyte and zinc for the negative electrode, such as mercury batteries, alkaline manganese batteries, and air 111i lead-acid batteries, if the electrolyte penetrates into the 8 parts, intense hydrogen gas will be released from the nickel surface and stainless steel surface (SUS304). This caused a decrease in discharge capacity and the generation of hydrogen gas, resulting in liquid leakage, and this 4X was unsuitable as a battery structure with high practical value. In the figure, 1 is the positive electrode case, 2
4 is a gas diffusion electrode, 4 is a gelled negative electrode zinc, 6 is a separator, 6 is a PTFE membrane, 7 is an insulating gasket, 8 is a positive electrode holding paper, and 9 is an air hole.

The present invention solves the drawbacks of the structure shown in FIG. 1, and will be described in detail below, including examples.

Conventionally, the contact area a between the sealing plates 3, 3' and the gasket 7 is generally coated with a sealant to improve leakage resistance, and various sealants such as epoxy resin, aliphatic amine, asphalt, etc. materials have been proposed and implemented. The purpose of this is to prevent infiltration of electrolyte and to fill gaps between various structural members.

The present inventors discovered that hydrogen gas generation occurs violently on the nickel surface in the structure shown in Figure 1, and that this can be prevented by applying a substance with a high hydrogen overvoltage to this end in some way. We have discovered that it is possible to significantly reduce the The present invention provides a means for achieving this goal and can be industrialized very easily. Specifically, the present invention introduces a metal salt having a high hydrogen overvoltage into a conventionally used sealant. Examples will be described below.

An R44 type air/zinc button battery is assembled in the same manner as before to create the structure shown in Figure 1.

In the present invention, 10 times more zinc perchlorate was added to the sealant. The sealant used was chlorosulfonate polyethylene dissolved in doluol. In the conventional example, only the same amount of the 7-lue agent made of the same material as the product of the present invention was applied to part a.

This invention product and the conventional product were introduced at a temperature of 46° C. and a humidity of 90%, and the leakage resistance and discharge capacity were investigated using a load resistance of 620Ω. The results are shown in the following table.

*Number of items that leaked after storing 1oO items The product of the present invention is excellent as described above, but the reason for this is, as mentioned above, when the alkaline electrolyte enters between the sealant and the negative electrode sealing plate, the seal It is presumed that this is because zinc quickly dissolves out from the agent and suppresses gas generation.

Although zinc perchlorate was used in the above examples, zinc borofluoride may also be used. As other salts, copper salts can be used similarly. Furthermore, if the amount added to the sealant is less than 6% by weight, the amount is too small and it takes a long time to dissolve it in the electrolytic solution.

On the other hand, if the amount is 26% by weight or more, the amount added will increase. If too much, the properties of the resin-based filler would be lost, so 6 to 20% by weight was appropriate.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a button-type air-zinc battery according to the present invention, and FIG. 2 is a sectional view of a conventional battery. 1...Positive electrode case, 2...Gas diffusion electrode,
3, 3'...Negative electrode sealing plate, 4...Negative electrode zinc, 6...Nana (shi~ri), 7...Insulating gasket, 9... ...Air vent. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2

Claims (1)

[Claims] This is a button-type battery in which the exit part of the positive electrode case is sealed with a negative electrode sealing plate and an insulating gasket that have no bent parts on the periphery, and a zinc salt is added to the fitting part of the negative electrode sealing plate end and the insulating gasket. A button-type battery coated with a sealant made of synthetic resin containing 6 to 20 parts by weight of copper salts.