JP2000315486A - Manganese dry battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve leakage resistance and to certainly operate the battery in abnormal rising of inner pressure in the battery, by providing a notch in the outer surface of the upper part of an inner cylinder of a sealed body to form a thin portion, and positioning a welding line of a molding in the center of the thin portion. SOLUTION: A part of the outer surface of the upper half of an inner cylinder 11 is notched to form a thin portion 11a, and a welding line is positioned in the center 14 of the thin portion 11a. A gate of a die for molding a sealed body 10 is located at a position deviated from the center of the die, during molding, molten resin filled into the die is intruded from the gate to the opposite side of the central hole of the sealed body, the welding line occurs on the opposite side of the gate with spaced by the central hole, and furthermore, the center 14 of the thin portion 11a is further thinned. In this structure, when inner pressure of this battery abnormally rises, gas presses up a connecting portion 13 of the sealed body 10, and generates a clearance between the inner cylinder 11 and a carbon bar to go outward. Therefore, a crack occurs in the thin portion 11a, gas goes through this crack part over the sealed body 10, and goes out of a gas exhausting hole in a positive electrode terminal plate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a sealed portion of a manganese dry battery in which an opening of a negative electrode zinc can is sealed with a sealing member made of a synthetic resin molded product.

[0002]

2. Description of the Related Art A manganese dry battery in which a metal jacket is abolished and is packaged with a label or a tube made of a heat-shrinkable synthetic resin film as a base material, when liquid leaks from around a sealing body for sealing a negative electrode zinc can, the manganese dry battery is immediately exposed to the outer surface. Because it comes out, the sealing performance by the sealing body is enhanced. Therefore, when misused, for example, when the battery is charged or reversely connected, gas accumulates and the danger of projecting the gas increases. Therefore, conventionally, an explosion-proof structure has been adopted in which a thin portion is provided in a part of the sealing body and the thin portion is broken when the internal pressure of the battery increases. However, there is a problem that it is difficult to obtain a uniform thin portion at the time of molding the sealing body, and the reliability as an explosion-proof mechanism is low.

[0003]

SUMMARY OF THE INVENTION In view of the above, the present invention provides a manganese dry battery having an explosion-proof mechanism which is excellent in liquid leakage resistance and which operates reliably when the internal pressure of the battery rises abnormally due to misuse. The purpose is to provide.

[0004]

According to the manganese dry battery of the present invention, a sealing body made of a synthetic resin molding for sealing an opening of a negative electrode zinc can is formed by an inner cylinder through which a carbon rod passes, and an inner cylinder and a connecting portion. A manganese dry battery having a connected outer cylinder, wherein the outer cylinder is fastened between the peripheral edge of the positive electrode terminal plate fitted to the top of the carbon rod and the open end of the negative electrode zinc can to seal the negative electrode zinc can. In addition, a cutout portion is provided on the upper outer surface of the inner cylinder of the sealing body to form a thin portion, and a weld line of the molded product is located substantially at the center of the thin portion. It is preferable that the weld line forming portion in the thin portion is further thinner.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The manganese dry battery of the present invention is provided with a thin portion at the upper part of the inner cylinder through which the carbon rod of the sealing body for sealing the opening of the negative electrode zinc can is inserted, as described above, to increase the internal pressure of the battery. An explosion-proof mechanism that sometimes cracks the thin part and releases gas from it. The weld line of the molded product of the sealing body is positioned substantially at the center of the thin portion. Since the weld line portion has a locally reduced strength against cracks, when the internal pressure rises abnormally, cracks can easily occur to allow gas to escape. If the thin portion is further thinned at the weld line, cracks can easily be generated when the pressure increases.

Hereinafter, embodiments of the present invention will be described in detail. FIG. 1 shows a battery according to the present invention. Reference numeral 1 denotes a bottomed cylindrical negative electrode zinc can. In the zinc can 1, a separator 2 is provided.
Through which the positive electrode mixture 3 mainly composed of manganese dioxide is filled. A carbon rod 4 is inserted into the center of the positive electrode mixture 3. Reference numeral 5 denotes a flange paper placed on the positive electrode mixture. Zinc can 1
1 made of polyethylene or the like to seal the opening
Reference numeral 0 denotes an inner cylinder 11, an outer cylinder 12, and a connecting portion 13 connecting the inner cylinder and the outer cylinder.
Outer peripheral edge of positive electrode terminal plate 6 fitted to the top of
Of the zinc can 1 to seal the opening of the zinc can 1. A sealant 8 such as asphalt is applied between the lower end of the inner cylinder 11 and the carbon rod 4 and between the lower end of the outer cylinder 12 and the inner wall surface of the zinc can 1. The positive electrode terminal plate 6 has a gas discharge hole 7.

The sealing body 10 will be described in more detail. In the prior art, the thickness of a part of the connecting portion 13, for example, the annular portion indicated by reference numeral 13 a is made thinner than the figure, but in the present invention, the thickness of the inner cylinder 11 is increased. A thin portion 11a is provided by cutting out a part of the half outer surface. The weld line is located at the center 14 of the thin portion 11a. That is, the gate position 1 of the mold for molding the sealing body 10
2 is provided at a position off the center of the mold as shown in FIG. 2, and the molten resin injected into the mold during molding is moved from the gate position 15 to the center hole of the sealing body shown in FIG. Let it flow around the other side. Then, a weld line is generated at a position indicated by a dashed line in FIG. 2 on the opposite side of the gate position 15 across the center hole. In this example, the central portion 14 of the thin portion 11a is made thinner. In the dry battery having such a configuration, when the battery internal pressure rises abnormally, the gas pushes up the connecting portion 13 of the sealing body 10 and tries to leave a gap between the inner cylinder 11 and the carbon rod 4, and this causes a problem. Then, a crack occurs in the thin portion 11a. Therefore, the gas escapes from the cracked portion onto the sealing body and exits through the gas exhaust hole 7 of the positive electrode terminal plate 6.

As described above, the thin portion 11a is provided on the upper portion of the inner cylinder 11 holding the carbon rod 4 of the sealing body 10 so that the weld line of the molded product is located substantially at the center. Combined with the fact that the connecting portion 13 is pushed up, the thin portion 11a surely cracks and functions as an explosion-proof mechanism. Taking a AAA battery as an example, in the case of a polyethylene sealing body, the wall pressure of the thin portion 11a is 0.1 mm.
5 to 0.8 mm, width 1.0 to 3.0 mm, length 0.5 to 1.8 mm for the length of the inner cylinder 2.0 to 3.5 mm
Is preferable. The thickness of the central portion 14 of the thin portion where the weld line is located is suitably in the range of 0.45 to 0.75 mm.

[0009]

As described above, according to the present invention, it is possible to obtain a manganese dry battery having an excellent explosion-proof mechanism which is excellent in liquid leakage resistance and operates reliably when the internal pressure of the battery rises abnormally.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view of a manganese dry battery according to one embodiment of the present invention.

FIG. 2 is a plan view of a sealing body of the dry battery.

FIG. 3 is a perspective view of a main part of the sealing body.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Negative electrode zinc can 2 Separator 3 Positive electrode mixture 4 Carbon rod 5 Flange paper 6 Positive electrode terminal board 7 Gas exhaust hole 8 Sealing agent 9 Exterior label 10 Sealing body 11 Inner cylinder, 11a Thin part 12 Outer cylinder 13 Connection part 14 Thin part Central part

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Keiji Ogino 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture F-term (reference) 5H011 AA13 FF02 GG01 HH02 JJ03 JJ04 5H012 AA01 BB04 DD02 DD03 DD05 DD17 EE01 FF01 GG01 JJ01

Claims (2)

[Claims] 1. A sealing body made of a synthetic resin molded article for closing an opening of a negative electrode zinc can having an inner cylinder through which a carbon rod penetrates, and an outer cylinder connected to the inner cylinder by a connecting portion. A manganese dry battery in which a tube is fastened between a peripheral portion of a positive electrode terminal plate fitted to a top portion of a carbon rod and an open end of a negative electrode zinc can to seal a negative electrode zinc can, and a top portion of an inner cylinder of the sealing body A manganese dry battery, wherein a notch portion is provided on an outer surface to form a thin portion, and a weld line of the molded product is located substantially at the center of the thin portion. 2. The manganese dry battery according to claim 1, wherein a weld line forming portion in the thin portion is further thinned.