JPH0716292Y2 - Explosion-proof battery sealing gasket - Google Patents

Description

[Detailed Description of the Invention] <Industrial application field> The present invention relates to a sealing gasket applied to a cylindrical alkaline battery or the like, and particularly, when the internal pressure of the battery is abnormally increased, the gas pressure is safely maintained. The present invention relates to a sealing gasket for explosion-proof batteries to be released.

<< Prior Art >> As a sealing gasket of this type, as shown in FIGS.
The one shown in the figure is known. FIG. 3 shows an alkaline battery equipped with this type of sealing gasket 1, FIG. 4 is an enlarged sectional view of a main part of the sealing gasket 1, and FIG. 5 is a sectional view taken along line VV in FIG. This sealing gasket 1
Is a boss portion 2 provided around a hole through which the metal collector rod A is inserted.
An annular outer tubular portion 3 held between the metal case B and the negative electrode terminal plate C, the boss portion 2 and the annular outer tubular portion 3
And a connecting portion 4 for integrally connecting and, and is usually manufactured by injection molding of a plastic such as polyethylene, polypropylene or nylon.

In the illustrated example, the connecting portion 4 has cone-shaped slope portions 4a and 4b having two-step taper angles with respect to the central axis O of the boss portion 2 and the annular outer cylindrical portion 3, Grooves 5 in the meridian direction are formed on the outer surfaces of the cone-shaped slope portions 4a, 4b. As shown in FIG. 5, the groove 5 is formed in a V-shaped valley shape, and this portion is thinner than the other portions.

Then, when the internal pressure of the battery is abnormally increased and the pressure reaches a predetermined pressure, the connecting portion 4 of the sealing gasket 1 breaks at the groove 5 so that the gas pressure can be safely released to the outside. Has become.

<< Problems to be Solved by the Invention >> The most important thing in the sealing gasket 1 as described above is to reduce the variation in the pressure at which the groove 5 breaks (this is referred to as the operating pressure) to reduce the breakdown voltage of the battery (the battery It is to operate properly at a predetermined pressure that is appropriately smaller than the maximum pressure that does not present a dangerous state of explosion) so that the breaking action is not too early or too late.

The conventional sealing gasket 1 is one in which a V-shaped groove 5 is formed at a predetermined position of the connecting portion 4, and in this case, the operating pressure sets the depth of the groove 5 appropriately, It is preset by appropriately setting the residual pressure d of the portion. Of course, the thickness D of the connecting portion 4 and the characteristics of the plastic material also have a great influence.

Conventionally, when the battery temperature is high, the sealing gasket 1
When the plastic material becomes soft and the internal pressure of the battery rises abnormally in that state, the connecting portion 4 of the gasket 1 receives the pressure and swells to the outside as a whole, and the groove 5 does not easily break. That is, since the connecting portion 4 is expanded and deformed as a whole, the breaking force is not concentrated in the groove 5, and as a result, the gasket 1 is not broken at a predetermined pressure, and the pressure inside the battery is further increased to increase the pressure resistance of the battery. When it becomes above, it invites itself to explode at a stretch.

The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to ensure that even if the temperature of the battery rises, the breaking operating pressure characteristic of the sealing gasket is stable and the variation is small, and the reliability is improved. It is to realize high explosion-proof performance.

<< Means for Solving the Problems >> Therefore, in the present invention, a sealing gasket is interposed between a metal case forming one electrode and a terminal plate forming the other electrode, and the sealing gasket is the metal case An annular outer cylindrical portion sandwiched between the terminal plate, a central thick portion, and a connecting portion that connects the outer cylindrical portion and the thick portion,
The connecting portion is a plastic sealing gasket in which a thin portion is formed along the meridian direction so as to break when the battery internal pressure rises abnormally, and the thin portion is wide and shallow. The structure is composed of a band-shaped groove and a V-shaped valley-shaped narrow groove formed along the center of the band-shaped groove.

<< Operation >> Since the periphery of the narrow groove is thinner than other portions due to the band-shaped groove, deformation due to the internal pressure of the battery is likely to concentrate on the thin-walled part including the narrow groove and the band-shaped groove. In other words, the circumference of the thin portion does not bulge and deform over a wide range as a whole, but bulging and deforming occurs intensively in the band-shaped groove portion, and the thin groove at the center thereof breaks from the narrow groove.

<< Embodiment >> FIG. 1 is an enlarged sectional view of a main part of a sealing gasket 1 according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along line II-II in FIG. The basic structure of the sealing gasket 1 of this embodiment is the same as that of the conventional one, and an annular shape held by a boss portion 2 provided around a hole for inserting the metal collector rod A, a metal case B and a negative electrode terminal plate C. A plastic molded product comprising an outer cylindrical portion 3 and a connecting portion 4 integrally connecting the boss portion 2 and the annular outer cylindrical portion 3 and having a thin wall along a meridian direction at a predetermined position of the connecting portion 4. The part 6 is formed.

As shown in FIG. 2, the feature of the present invention is that the thin portion 6 has a wide and shallow strip-shaped groove 6a and a V-shaped thin groove 6b formed along the inner center of the strip-shaped groove 6a. This is the point that the groove structure is formed in stages. As a specific example, the residual thickness d of the narrow groove 6b is the same as the residual thickness d in the conventional example of FIG.
The residual thickness D of the portion 6a is the same as the thickness D of the conventional connecting portion 4 shown in FIG. Therefore, the thickness of the connecting portion 4 in FIG.
Larger than the conventional one in the figure.

If the internal pressure of the battery rises when the temperature of the battery is high and the sealing gasket 1 is softened, the sealing gasket 1 is likely to be deformed as a whole, but the thin portion of the band-shaped groove 6a is apt to be deformed due to the swelling due to the internal pressure of the battery. Occurs and V at its center
The gasket 1 is broken starting from the groove-shaped narrow groove 6b.

<< Effects of the Invention >> As described in detail above, in the sealing gasket for an explosion-proof battery according to the present invention, the thin-walled portion has two parts, the strip-shaped groove and the narrow groove.
Due to the stepped structure, the parts other than the thin part are deformed as a whole and the inconvenience that the deformation is not effectively concentrated in the thin part (groove) is eliminated. Also, the deformation due to the internal pressure of the battery is effectively concentrated in the band-shaped groove portion, and the breaking operation is stably performed starting from the narrow groove.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of a main part of a sealing gasket according to an embodiment of the present invention, FIG. 2 is a sectional view taken along the line II-II of FIG. 1, and FIG. 3 is a schematic configuration of a battery equipped with an explosion-proof sealing gasket. Figure,
FIG. 4 is an enlarged sectional view of a main part of a conventional sealing gasket, FIG.
The drawing is a sectional view taken along line VV in FIG. 1 ... Sealing gasket, 2 ... Boss part 3 ... Annular outer cylinder part, 4 ... Connection part 5 ... Groove, 6 ... Thin wall part 6a ... Strip groove, 6b ... Fine groove

Claims (1)

[Scope of utility model registration request] 1. A sealing gasket is interposed between a metal case forming one electrode and a terminal plate forming the other electrode, and the sealing gasket is sandwiched between the metal case and the terminal plate. A ring-shaped outer cylinder part, a central thick part, and a connecting part that connects the outer cylinder part and the thick part, and the connecting part is configured to break when the battery internal pressure rises abnormally. A plastic sealing gasket having a thin-walled portion partially formed along the meridian direction in the thin-walled portion, the thin-walled portion having a wide and shallow band-shaped groove and a V formed along the center of the band-shaped groove.
Explosion-proof battery gasket, which is characterized by being composed of narrow grooves in a valley shape.