JPH0511651Y2 - - Google Patents

Description

[Detailed Description of the Invention] <<Industrial Application Field>> This invention relates to the sealing structure of a cylindrical manganese battery, and in particular to safety measures when the internal pressure becomes abnormally high.

<Prior Art> In the case of a conventional cylindrical manganese battery packaged with a metal jacket, the sealing performance of the joint between the negative electrode zinc can and the plastic gasket is not very high, and it is easy to charge the battery by mistake. If the internal pressure becomes abnormally high, gas will leak out from around the gasket relatively easily, and an explosion is unlikely. Along with gas, leakage of electrolyte also occurs,
Since the area around the cell is covered with a metal jacket, this is not a big problem. In other words, in the case of a metal jacket type battery, there was no need to tightly seal the negative electrode zinc can with a sealing gasket because the battery was double sealed with a metal jacket.

However, recently, in order to reduce costs, a manganese battery has been developed that eliminates the metal jacket and simply covers the unit cell (the zinc can is exposed) with a label based on heat-shrinkable plastic film. Ta. This is called the shrink-tack label method as opposed to the metal jacket method.

In the case of shrink-tack label type manganese batteries, if electrolyte leaks from around the gasket, it will immediately come out to the outside surface, so the zinc can must be tightly sealed with a gasket. Therefore, instead of the gasket used in metal jacket type batteries,
A gasket similar to that used in alkaline batteries is used to create a tight seal.

《Problems that the invention aims to solve》 As mentioned above, in the shrink-tack-label type manganese battery, if the negative electrode zinc can is highly sealed, gas will not escape easily even if it is accidentally charged. Increased risk of explosion. Therefore, explosion-proof measures are required, but this has not been taken into consideration with conventional manganese batteries of this type.

By the way, in the case of alkaline batteries, the electrolyte tends to creep very easily, so various measures have been taken to improve the sealing performance and leakage resistance of the battery case. At the same time, since alkaline batteries are prone to gas-generating reactions, the danger of explosion has long been pointed out, and many current products are now equipped with explosion-proof measures.

Typical explosion protection measures found in alkaline batteries include:
When the internal pressure becomes too high, a part of the gasket ruptures due to the pressure. This method can be carried out at low cost, and some methods have good performance in venting gas in emergencies. However, the drawback is that once the gasket ruptures, the battery can no longer be used.

In the case of alkaline batteries, which are prone to sudden gas generation, safety is given priority, and the explosion-proof measures described above are actually adopted. However, since the gas generation reaction of manganese batteries is not so violent, it is not desirable to take explosion-proof measures that would render the battery unusable once activated.

This idea was devised in view of the above-mentioned conventional problems, and its purpose was to be able to implement it at low cost in line with the intent of the shrink-tack label system, and to reliably prevent liquid leakage and intrusion of outside air. An object of the present invention is to provide a sealing structure for a cylindrical manganese battery, which allows gas to escape when the internal pressure becomes excessive, and seals the inside again when the internal pressure decreases.

<Means for solving the problem> Therefore, in this invention, a plastic gasket in which the inner cylinder part and the outer cylinder part are integrally molded together with the connecting part is used, and the carbon rod as the positive electrode current collector is inserted into the inner cylinder. The outer cylindrical part is fitted to the inner periphery of the opening edge of the negative electrode zinc can, the positive electrode terminal plate is placed over the upper end protrusion of the carbon rod, and the outer periphery of the positive electrode terminal plate is fitted. In a sealed structure for a cylindrical manganese battery in which the outer cylindrical part of the gasket is compressed from the inner and outer periphery by the opening edge of the negative electrode zinc can, the upper end surface of the inner cylindrical part of the gasket is brought into pressure contact with the lower surface of the positive terminal plate. At the same time, by cutting out a portion of the upper end of the inner cylinder of the gasket on the carbon rod side, a locally thinned valve part was formed on the peripheral wall of the inner cylinder.

<<Operation>> When the internal pressure becomes excessive, the gasket tends to escape from between the inner cylindrical portion of the gasket and the carbon rod. Then, the internal pressure also acts on the valve portion, causing the valve portion to bend and deform outward, creating a gap between the valve portion and the positive terminal plate. Gas escapes through these gaps and the exhaust hole. When the internal pressure decreases, the valve section returns to its original state due to its elasticity, eliminating the gap.

<<Embodiment>> FIGS. 1 and 2 show the structure of an embodiment of the present invention.

In the figure, 1 is a bottomed cylindrical negative electrode zinc can, 2
is a positive electrode mixture wrapped in a separator 3 and filled in a zinc can 1; 4 is a carbon rod (positive electrode current collector) inserted into the center of the positive electrode mixture 2; 5 is a plastic gasket; 6 is a carbon rod 4 The positive terminal plate 7, which is placed over the protruding end of the gasket 5 and the upper surface of the gasket 5, is the shrink connector label described above.

The gasket 5 is an integrally molded polyethylene product, and has an inner cylindrical portion 51 and an outer cylindrical portion 52 arranged coaxially and connected together with a connecting portion 53. The carbon rod 4 is passed through the gasket inner cylindrical part 51 tightly, and the gasket outer cylindrical part 52 is fitted onto the inner periphery of the opening edge of the zinc can 1. The positive electrode terminal plate 6 is placed thereon, and the outer circumferential edge of the terminal plate 6 is fitted into the inner circumference of the gasket outer cylindrical portion 52. Then zinc can 1
The opening edge of the gasket is curled inward, and the gasket outer cylinder part 52 is compressed by the zinc can 1 and the terminal plate 6, and the terminal plate 6 is pressed downward.

Note that a sealant 8 such as Pitch is applied around the gasket 5.

The present invention is characterized by the following configuration: A small exhaust hole 61 is formed in the portion of the terminal board 6 that is almost hidden by the label 7.

Further, the upper end surface of the gasket inner cylindrical portion 51 is pressed against the lower surface of the intermediate flat portion of the terminal plate 6 as shown in the figure. In this portion, a local notch 51a is provided at the upper end of the inner cylindrical portion 51 on the carbon rod 4 side, and a thin wall portion 51b is left on the outer circumferential side. This thin part 51b
is the first valve part.

In the above configuration, when the internal pressure becomes excessive, a large pressure also acts on the valve portion 51b, which is bent outward and a gap is created between the valve portion 51b and the terminal plate 6. Gas escapes through this gap and the exhaust hole 61 of the terminal board 6. This gas passage is shaped like a narrow labyrinth, so the electrolyte is difficult to leak. When the gas escapes and the internal pressure decreases, the valve portion 51b closes due to its elasticity.

<<Effects of the invention>> As explained in detail above, according to the present invention,
As a cylindrical manganese battery using the Shrink Tatsuclavel method, it can provide a sufficiently high-performance seal, and when the internal pressure becomes excessive, gas can escape to prevent an explosion, and if the gas escapes and the internal pressure drops, The battery is resealed and ready for further use. In addition, since the valve part can be formed only by the inner cylinder part of the gasket that presses against the positive terminal plate,
The manufacturing process for the valve part is reduced. Furthermore, the operating pressure of the valve part as the battery internal pressure increases can be controlled by its material and thickness.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a sealing structure according to an embodiment of the present invention, and FIG. 2 is a plan view of a gasket in the same embodiment. 1... Negative electrode zinc can, 2... Positive electrode mixture, 3... Separator, 4... Carbon rod, 5... Gasket, 6
...Positive electrode terminal plate, 7...Shrink connector label, 8...Sealant, 51...Inner cylinder part, 52...
Outer cylinder part, 53... Connection part, 51b... Valve part, 61
...Exhaust hole.

Claims (1)

[Claims for Utility Model Registration] (1) Using a plastic gasket in which the inner cylinder part and the outer cylinder part are integrally molded together with the connecting part, a carbon rod as a positive electrode current collector is tightly penetrated into the inner cylinder part. At the same time, the outer cylindrical part is fitted to the inner periphery of the opening edge of the negative electrode zinc can, and the positive electrode terminal plate is placed over the upper end protrusion of the carbon rod, and the outer periphery of the positive electrode terminal plate and the negative electrode zinc In a sealing structure for a cylindrical manganese battery in which the outer cylindrical part of the gasket is compressed from the inner and outer peripheries by the opening edge of the can, the upper end surface of the inner cylindrical gasket part is brought into pressure contact with the lower surface of the positive terminal plate, and the inner cylindrical part of the gasket is pressed against the lower surface of the positive terminal plate. A sealing structure for a cylindrical manganese battery, characterized in that a valve portion having a locally thinned wall is formed on the peripheral wall portion of the inner cylindrical portion by partially cutting out an upper end portion on the carbon rod side of the inner cylinder portion. (2) The sealed structure for a cylindrical manganese battery according to claim 1, which is characterized in that an exhaust hole is formed in a part of the positive terminal plate.