JPH0877996A - Battery - Google Patents

Abstract

PURPOSE: To prevent the leakage of electrolyte solution to the battery outside through a gas vent hole in a sealing part so as to improve an antileakage properly in a battery provided with a thin part serving as an explosion-proof mechanism in a gasket. CONSTITUTION: Inside a sealing body 5, a water repellent high polymer film 10 which is provided with gas permeability and prevents impregnation of liquid is arranged between a ring washer 8 and a gasket 7, and at least the outer circumference part and the inner circumference part of the water repellent high polymer film 10 are put between the gasket 7 and the ring washer 8 so as to be pressure fitted and sealed. In this way, only the gas inside a battery is discharged, even when gas generated inside the battery increases a battery internal pressure and a safety valve in a thin part serving as an explosion-proof mechanism is operated, so that electrolyte solution is prevented from leaking to the battery outside, and consequently, a battery provided with a high antileakage property can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery having a safety valve, which is an explosion-proof mechanism for preventing an increase in internal pressure of the battery due to gas generation, with improved safety and leakage resistance when the safety valve operates. Is.

[0002]

2. Description of the Related Art A conventional alkaline battery, for example, an alkaline dry battery has a structure as shown in FIG. After the positive electrode mixture 2 made of manganese dioxide and graphite is put in the metal case 1 and the separator 3 is inserted, the gelled negative electrode 4 made of the alkaline electrolyte, zinc powder and the gelling agent is filled in the separator 3. The sealing body 5 in which the negative electrode current collector 6, the gasket 7, the annular washer 8 and the bottom plate 9 are integrated is used as a gel negative electrode 4.
A plug-in cell is formed.

In the alkaline battery as described above, as one of measures for increasing gas internal pressure by generating gas from zinc of the negative electrode due to misuse such as charging and over-discharging, a safety valve, which is an explosion-proof mechanism provided in the gasket, is used. It was operated to discharge the gas inside the battery (for example, JP-A-63-30456).
No. 8).

[0004]

However, in the conventional explosion-proof mechanism, when the internal pressure of the battery rises and the safety valve is activated, not only the gas inside the battery but also the electrolytic solution passes through the gas vent hole of the annular washer in the sealing body and the bottom plate There is a problem that the gas leaks or scatters to the outside of the battery through the gas vent hole.

The present invention solves the above-mentioned problems of the prior art. When the safety valve, which is an explosion-proof mechanism, is activated, only the gas inside the battery is discharged to prevent the electrolyte from leaking or scattering to the outside. The purpose is to

[0006]

To solve this problem, the present invention provides a metal case containing a positive electrode active material and a negative electrode active material, and an explosion-proof thin wall for sealing an opening at one end of the metal case. A gasket having a portion, an annular washer having a gas vent hole located outside the gasket to reinforce the gasket, and a gas vent located near the opening and exposed to the outside of the metal case A battery having a negative electrode bottom plate each having a hole, wherein a water-repellent polymer film that is gas permeable but blocks permeation of a liquid is provided in the sealing body, and further, between the annular washer and the gasket. Is provided with a water-repellent polymer film that has gas permeability but prevents liquid penetration, or there is gas permeability between the annular washer and the bottom plate but liquid penetration does not occur. Providing the water-repellent polymer film stop, as further closes the gas release openings of the negative electrode base plate,
It is characterized in that a water-repellent polymer film that has gas permeability and blocks liquid permeation is bonded.

[0007]

With this structure, when the internal pressure of the battery rises due to gas generation and the safety valve, which is an explosion-proof mechanism provided in the gasket, is activated, the gas inside the battery is discharged to the outside of the battery. This makes it possible to prevent the electrolyte from leaking or scattering outside the battery.

[0008]

EXAMPLES Example 1 An alkaline battery which is an example of the present invention, and FIG. 1 is an enlarged half cross-sectional view of a main part of this battery.

A sealing body 5 for sealing an opening at one end of a metal case in which a steel plate is nickel-plated has an explosion-proof thin portion in order from the inside, a gasket 7 made of polyamide resin, polypropylene resin or the like, and gas permeation. However, a liquid-repellent polymer film 10 made of, for example, fluoroethylene propylene, which prevents liquid, a circular washer 8 made of stainless steel having a gas vent hole, a bottom plate 9 having a gas vent hole and having a steel plate plated with nickel are incorporated. Is configured. At this time, the outer peripheral portion and the inner peripheral portion of the water-repellent polymer film 10 are sandwiched between the gasket 7 and the annular washer 8 to be pressure-bonded and sealed. Other battery configurations are the same as those of conventional batteries.

(Embodiment 2) An alkaline battery which is another embodiment of the present invention is shown in FIG. The components are the same as those of the above-described first embodiment, only the position of the water-repellent polymer film 10 is different, and the outer peripheral portion of the water-repellent polymer film 10 is sandwiched between the annular washer 8 and the bottom plate 9,
The inner peripheral part is sandwiched between the lower part of the head of the negative electrode current collector 6 and the inner part of the annular washer 8 to be pressure-bonded and sealed. Other battery configurations are the same as those of conventional batteries.

(Embodiment 3) An alkaline battery which is another embodiment of the present invention is shown in FIG. The components are the same as in Example 1 above, only the position of the water-repellent polymer film 10 is different, and the components are attached and adhered to the inside of the bottom plate in advance before assembling the sealing body.
The gas vent hole of the bottom plate 9 is sealed. It is more preferable that the outer peripheral portion of the water-repellent polymer film attached to the bottom plate is sandwiched between the outer peripheral portion of the bottom plate and the outer peripheral portion of the annular washer and pressure-bonded. Other battery configurations are the same as those of conventional batteries. Furthermore, by attaching the water-repellent polymer film to the inside of the bottom plate in advance, the film is not peeled off even after the assembly process of the sealing body or the product is completed, and the gas vent hole can be completely closed.

As described above, if the water-repellent polymer film is pressure-bonded inside the sealing body of the alkaline battery or attached to the inner surface of the bottom plate so as to close the gas vent hole, gas will be generated due to misuse such as charging and over-discharging. Even if the internal pressure of the battery rises and the safety valve, which is an explosion-proof mechanism in the sealed body, activates and gas is discharged to the outside of the battery, it is possible to prevent the alkaline electrolyte from leaking out or scattering to the outside of the battery, and the resistance to leakage is improved. Can be improved.

As the material of the water-repellent polymer film 10 used in the above embodiment, which allows the gas to permeate but prevents the liquid,
Although fluoroethylene propylene was used, the same effect can be obtained with natural rubber, methyl rubber, polybutadiene, polyvinyl butyral, polyethylene, ethyl cellulose, polypropylene, silicone rubber, ethylene-vinyl acetate copolymer, polyphenylene oxide, polytetrafluoroethylene, etc. .

The gas permeation rate of the water-repellent polymer membrane varies depending on the size of the battery used and the area of the gas vent hole, but from the membrane having the permeation rate in the range of 50 to 1000 ml / min · cm ³ , It is preferable to use a type alkaline dry battery that is compatible with the gas generation rate of each size.

[0015]

As described above, according to the present invention, when the internal pressure of the battery rises due to the generation of gas inside the battery and the safety valve which is the explosion-proof mechanism is activated, the gas inside the battery is discharged to the outside of the battery. It is possible to realize an excellent battery in which the electrolytic solution can be prevented from leaking out or scattering to the outside of the battery by the water-repellent polymer film which has the property of preventing the penetration of the liquid.

[Brief description of drawings]

FIG. 1 is an enlarged half sectional view of a sealing body portion of an alkaline battery used in an embodiment of the present invention.

FIG. 2 is an enlarged half sectional view of a sealing body portion of an alkaline battery used in Example 2 of the present invention.

FIG. 3 is an enlarged half sectional view of a sealing body portion of an alkaline battery used in Example 3 of the present invention.

FIG. 4 is a half sectional view of a conventional alkaline battery.

[Explanation of symbols]

 5 Sealing body 6 Negative electrode current collector 7 Gasket 8 Annular washer 9 Bottom plate 10 Water repellent polymer film

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Junichi Asaoka 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Isao Kubo, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (4)

[Claims] 1. A metal case containing a positive electrode active material and a negative electrode active material, a gasket having an explosion-proof thin portion for sealing an opening at one end of the metal case, and the opening outside the gasket. In a battery provided with a negative electrode bottom plate having a gas vent hole that is located in the vicinity and is exposed to the outside of the metal case, a gas permeable but liquid permeation is blocked between the gasket and the bottom plate. A battery with a water-repellent polymer film. 2. A metal case containing a positive electrode active material and a negative electrode active material, a gasket having an explosion-proof thin portion for sealing an opening at one end of the metal case, and a gasket positioned outside the gasket. An annular washer having a gas vent hole reinforcing the gasket and a negative electrode bottom plate having a gas vent hole exposed near the opening and exposed to the outside of the metal case. Between the gasket and the annular washer is provided with a water-repellent polymer film that is gas permeable but prevents the permeation of liquid between the gasket and the gasket. A battery that is sandwiched between, crimped and sealed. 3. A metal case containing a positive electrode active material and a negative electrode active material, a gasket having an explosion-proof thin portion for sealing an opening at one end of the metal case, and a gasket located outside the gasket. An annular washer having a gas vent hole reinforcing the gasket and a negative electrode bottom plate having a gas vent hole exposed near the opening and exposed to the outside of the metal case. And a bottom plate having gas permeability between the bottom plate and a water-repellent polymer film for preventing the penetration of liquid, the outer peripheral portion of the water-repellent polymer film is sandwiched between the gasket and the annular washer, A battery, wherein the inner peripheral portion is sandwiched between the lower portion of the head of the negative electrode current collector and the inner portion of the annular washer, and is crimped and sealed. 4. A metal case containing a positive electrode active material and a negative electrode active material, a gasket having an explosion-proof thin portion for sealing an opening at one end of the metal case, and the opening outside the gasket. In a battery each having a negative electrode bottom plate having a gas vent hole that is located in the vicinity and is exposed to the outside of the metal case, a liquid having gas permeability so that the gas vent hole of the bottom plate is closed from the inside. A battery having a water-repellent polymer film bonded to prevent the permeation of the battery.