JPH0696749A - Dry battery - Google Patents

Abstract

PURPOSE:To reduce a space between a film and the surface of an element battery to prevent the leakage of the electrolyte by adhering a thin film to the inside of an overlap part of a thermal shrink tube, which is obtained by overlapping and bonding both ends of a film to form it into the cylindrical shape. CONSTITUTION:A thermal shrink film 4 thinner than a film 3 forming a tube is adhered to the inside of an overlap part of the film 3. In the case where the film at 5-35mum of thickness is used, a space due to the stage difference of the film overlap part can be reduced, and the leakage of the electrolyte from the inside of an element battery to the outside through a space between the film and the element battery can be restricted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dry battery, and more particularly to a dry battery using a heat shrinkable tube.

[0002]

2. Description of the Related Art As a heat-shrinkable tube used for preventing leakage of a dry battery, two types of structures have been used conventionally.

One is a tube 1 formed in a seamless cylindrical shape as shown in FIG. The other is a tube 2 obtained by continuously moving one strip-shaped film as shown in FIG. 2 and stacking both ends of the film in a tubular shape and adhering it (hereinafter, the latter tube is a center-seal type tube). Called).

The former tube is not stable in quality except for polyvinyl chloride as a raw material in the construction method. The latter tube is not only polyvinyl chloride,
It can be manufactured by a single or composite film of polyethylene terephthalate, polystyrene, polypropylene, polyethylene, and it is easy to improve environmental problems and heat resistance.

[0005]

However, when the center-seal type tube is used for the interior of a dry battery, a space is created between the surface of the unit cell due to the step between the overlapping portions of the films as shown in FIG. There was a quality problem that the liquid from the inside of the unit cell leaked to the outside during overdischarge. The present invention solves the above-mentioned conventional problems, and provides a structure of an interior center-seal type tube capable of maintaining the liquid leakage resistance of a dry battery at a high level.

[0006]

The structure of the tube according to the present invention is a center-seal type tube in which a thinner heat-shrinkable film is adhered to the inside of the overlapping portion of the films, or both ends of a strip-shaped film. Are made to butt without overlapping, and a thinner film is adhered to the inside of the abutted part or both inside and outside.The space between the film and the cell surface is reduced by the step of the overlapping part of the film. It is characterized by doing.

[0007]

By using the tube of this structure as the inner tube for the dry battery, the space between the film and the surface of the unit cell due to the step of the overlapping portion of the film can be made small. It is possible to prevent the liquid from leaking to the outside of the battery through the film and the unit cell.

[0008]

EXAMPLES The present invention will be described in detail below with reference to examples.

(Embodiment 1) FIG. 3 shows a structure of a cross section of a tube and an overlapping portion of a film in an embodiment of the present invention. In FIG. 3, a battery was manufactured by using a tube in which a heat-shrinkable film 4 thinner than the film forming the tube is bonded inside the overlapping portion of the film 3.

(Example 2) As shown in FIG. 4, a battery was manufactured by using a tube in which both ends are abutted with each other without overlapping and a heat-shrinkable film 4 is adhered to the inside.

Example 3 A battery was manufactured by using a tube obtained by adhering a heat-shrinkable film 5 to the outside of the tube obtained in Example 2 as shown in FIG. In this case, since the tensile strength of the abutting portion is improved, the thickness of the film adhered to the inside can be further reduced.

Generally, the thickness of the film forming the tube is 50 to 100 μm. On the other hand, when the thickness of the film adhered to the inside of the tube is 35 μm or more, the space between the film and the surface of the unit cell cannot be made too small, and the liquid leakage resistance cannot be maintained at a high level. Therefore, in the case of Example 1 (FIG. 3), 5 to 35 μm, in the case of Example 2 (FIG. 4), 30 to 35 μm, and in the case of Example 3 (FIG. 5), the inner side is 5 to 35 μm and the outer side is 10 to 40 μm. By using the tube having the above structure as the interior tube for the dry battery, the space due to the step difference in the overlapping portions of the films can be reduced.

Table 1 shows the comparison results in the leakage resistance test (three days after constant resistance 2Ω continuous discharge) of the batteries using the tubes of the present invention product and the conventional product (center seal system).
In all of the three examples of the present invention, no liquid leakage was observed, and this result confirms that the present invention greatly contributes to the improvement of the liquid leakage resistance performance of the dry battery.

[0014]

[Table 1]

[0015]

According to the structure of the present invention, since the space between the film and the unit cell can be made small, it is possible to prevent the liquid from leaking to the outside of the battery through the space, and the high level of leakage resistance property. Is obtained. Also, by adopting this configuration, it is possible to use resins other than polyvinyl chloride,
It is also possible to provide a dry battery having excellent heat resistance, which solves environmental problems without using a chlorine-containing resin.

[Brief description of drawings]

FIG. 1 is a perspective view of a tube having a conventional structure (a seamless tube).

FIG. 2 is a perspective view of a tube (center seal type) having a conventional structure.

FIG. 3 is a sectional view of a joint portion of a tube according to an embodiment of the present invention.

FIG. 4 is a sectional view of a seam portion in another embodiment of the present invention.

FIG. 5 is a sectional view of a seam portion in another embodiment of the present invention.

[Explanation of symbols]

 1, 2 tube 3 film 4,5 heat shrinkable film

Claims (3)

[Claims] 1. A dry battery in which a power-generating element is housed and an opening is sealed with an electrically insulating gasket to cover the outside of a battery case with a heat-shrinkable tube, the heat-shrinkable tube having a tubular film shape. A dry battery, which is a tube having both ends overlapped and adhered, and a film thinner than the film is adhered to the inside of the overlapping portion of the films. 2. A dry battery in which a power-generating element is housed and the opening is sealed with an electrically insulating gasket to cover the outside of a battery case with a heat-shrinkable tube, wherein the heat-shrinkable tube is formed into a tubular film. It is a tube with both ends butted,
A dry battery, characterized in that a film thinner than the film is adhered to the inside of the abutted portions of the film. 3. A dry battery in which a power-generating element is housed and an opening is sealed with an electrically insulating gasket to cover the outside of a battery case with a heat-shrinkable tube, wherein the heat-shrinkable tube has a tubular film shape. A dry battery, which is a tube having both ends butted, and a film thinner than the film is adhered to both the inside and the outside of the butted part of the film.