JPH0511652Y2 - - 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 conventional cylindrical manganese batteries that are packaged with metal jackets, the sealing properties of the joint between the negative electrode zinc can and the plastic gasket are not very high, and there is a risk of accidental charging. If the internal pressure becomes too high, gas will leak out from around the gasket relatively easily, and an explosion is unlikely. Liquid leakage occurs along with gas, but since the area around the cell is covered with a metal jacket,
It's not that much of a 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 liquid leaks 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 improve the sealing performance.

<<Problems to be solved by the invention>> As mentioned above, in the shrink-tack label type manganese battery, the hermeticity of the negative electrode zinc can is improved. In this case, even if the battery is accidentally charged, the gas will not escape easily, increasing the 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 made in view of the conventional problems mentioned above, and its purpose is to be able to implement it at low cost in accordance with the intention of the shrink-tack label method, 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 is used in which the inner cylinder part and the outer cylinder part are integrally molded together with the connecting part, 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, and the positive terminal plate is placed over the protruding upper end of the carbon rod. 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 part of the upper end of the inner cylinder of the gasket on the carbon rod side, a first valve part having a locally thinner wall is formed on the peripheral wall of the inner cylinder, and the outer circumference of the carbon rod is cut out. A groove extending vertically is formed on the inner circumferential surface of the inner cylindrical portion of the gasket that is in pressure contact with the gasket, and a thin second valve portion is formed midway to partition the groove into an upper and lower part, and the first valve portion and the second valve portion are connected to each other. were spatially connected.

<<Operation>> When the internal pressure becomes excessive, the second valve section first bends in response to the pressure, creating a gap between the can and the carbon rod, through which gas attempts to escape. Then, the internal pressure also acts on the first valve section, the first valve section is bent, and a gap is created between the can and the positive terminal plate, and gas escapes through this gap and the exhaust hole. When the internal pressure decreases, the first valve part and the second valve part return to their original positions due to their 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 feature of the present invention lies in the configuration described below. A small exhaust hole 61 is formed in a portion of the terminal plate 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 peripheral side. This thin part 51b
is the first valve part.

Furthermore, a thin groove 51c extending vertically is formed on the inner circumferential surface of the gasket inner cylindrical portion 51. This groove 5
1c is not completely continuous and is partitioned by a thin wall portion 51d left in the middle. This thin part 5
1d is the second valve portion. The second valve section is spatially communicated with the first valve section.

In the above configuration, when the internal pressure becomes excessive, the second valve portion 51d is bent upward due to the pressure, and a gap is created between the second valve portion 51d and the carbon rod 4. Then, the first valve part 5
A large pressure is also applied to 1b, which bends and deforms outward, creating a gap between it and the terminal plate 6. Gas escapes through these gaps and the exhaust hole 61 of the terminal board 6. This gas passage is provided with first and second valve portions spaced apart from each other to vent gas in stages, so that the electrolyte is less likely to leak out. When the gas escapes and the internal pressure decreases, the first valve part 5
1b and the second valve portion 51d are elastically closed.

<<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 first and second valve parts can be formed in the inner cylindrical part of the gasket, not only can the manufacturing process of the valve parts be reduced, but also the operation of the first and second valve parts as the internal pressure of the battery increases. The pressure can be controlled by its material and thickness.

Furthermore, in the event of a prolonged or extremely significant increase in internal pressure, the two valves will release the gas in stages, preventing the sealing material and electrolyte pushed out by the gas from leaking outside. can be prevented.

[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 terminal plate, 7... Shrink connector label, 8... Sealing agent, 51... Inner cylinder part, 52...
Outer cylinder part, 53...connecting part, 51b...first valve part,
51c...Groove, 51d...Second valve portion, 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 pressed against the lower surface of the positive terminal plate, and the inner cylindrical part of the gasket A first valve portion having a locally thinned wall is formed on the peripheral wall portion of the inner cylinder portion by partially notching the upper end portion of the portion on the carbon rod side, and the gasket is pressed against the outer periphery of the carbon rod. A groove extending vertically is formed on the inner peripheral surface of the inner cylinder part, and a thin second valve part is formed midway to partition the groove into upper and lower parts, so that the first valve part and the second valve part are spatially connected. A sealed structure for a cylindrical manganese battery characterized by: (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.