JPH0589866A - Battery with safety mechanism - Google Patents

Abstract

PURPOSE:To provide a battery fitted with a safety mechanism which has a vent mechanism easy to adjust the vent pressure operating stably with a low pressure not leading to rupture of the battery even though a gas generation therein has boosted the battery internal pressure. CONSTITUTION:A battery case 1 is provided with a hole 3, whose edge projects to the outer side, to exhaust gas from the battery. A hot-bond, type resin of polyolefin type 4 is applied on the outside of the hole 3 in such a way as enclosing the projection and blocking the hole 3, and thereby the battery case 1 is sealed. Therein the angle theta and dimension (h) of the projection at the edge of the hole 3 are changed to adjust the actuation pressure of the safety mechanism.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery with a safety mechanism.

[0002]

2. Description of the Related Art A non-aqueous electrolyte battery using lithium as a negative electrode active material and a non-aqueous electrolyte as an electrolyte has a high energy density,
It has excellent high voltage and long-term storability, and is widely used as a power source for memory backup and power source for communication equipment. However, on the other hand, the sealing is extremely tight and airtight so that it can withstand long-term use.Therefore, when the internal short circuit and external short circuit of the battery or the temperature is forced to rise from the outside, The internal pressure increased and the battery sometimes burst.

Therefore, conventionally, the following explosion-proof structure has been proposed. (1) A thin portion is provided in a part of the battery case, and even if the internal pressure rises, the thin portion is broken before the battery ruptures, and the battery internal pressure is released.

(2) Assembling the battery In the sealing plate, a thin metal plate, a synthetic resin or a synthetic rubber thin plate as a sealing member,
Alternatively, a composite membrane in which the both are bonded is arranged, and the thin plate that has expanded when the internal pressure rises is broken by a sharp projection to release the internal pressure of the battery.

(3) A gas vent hole is provided in the battery case and the sealing plate, the hole is covered with a composite coating of a plastic film having adhesiveness to metal and a metal thin film, and the periphery of the hole is heat-sealed. When the internal pressure rises, the heat-sealed portion comes off and the internal pressure is released.

[0006]

However, in the case of the above (1), in the case of forming a thin portion in the iron battery container with such a structure, the thickness of the thin portion is 0.08 to 0 due to processing accuracy.
The reality is that it can only be processed to a thin thickness of about 15 mm. In this case, the explosion-proof function does not work unless the internal pressure of the battery reaches a high pressure of 50 to 70 kg / cm ² .

In the case of the above (2), synthetic rubber,
When thin plates of synthetic resin or the like are used, these thin plates easily penetrate moisture in the atmosphere and are not suitable for non-aqueous electrolyte batteries. When using a thin metal plate, the thickness must be on the order of several μm in consideration of low-pressure operability. It is important to insert and fix such a thin plate in the assembly sealing plate by the caulking method. Smell problem occurs.

In the case of the above (3), since the internal pressure release valve operating pressure is adjusted only by heat-sealing the plastic, the safety valve operating pressure can be adjusted only at a low pressure, and the ambient temperature etc. There is a problem that a malfunction is likely to occur due to the reason that the safety valve is likely to be disengaged due to an external contact or the like.

The present invention has been made in order to solve the above problems, and provides a battery with a safety mechanism which is easy to manufacture, the vent pressure can be easily adjusted, and operates stably at a low pressure. The purpose is to

[0010]

In the battery with a safety mechanism of the present invention, a peripheral edge of the battery case or the sealing plate is projected outward to form a hole for discharging gas inside the battery. The projection is covered on the outside, a thermoadhesive polyolefin-based resin is outsert so as to close the hole, and the case or the sealing plate is sealed.

[0011]

The battery with a safety mechanism according to the present invention, when the internal pressure of the battery rises, the internal pressure discharging mechanism operates stably at a low pressure, and the advantageous long-term storage characteristics of the non-aqueous electrolyte battery are not impaired. It is possible to provide a battery having stable airtightness, excellent liquid leakage resistance, and stable battery characteristics. Further, the safety mechanism operating pressure can be adjusted by adjusting the angle and size around the projected hole.

[0012]

【Example】

Example 1. FIG. 1 is a sectional view of a main part of a battery with a safety mechanism according to an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of the safety mechanism portion. As shown in the figure, the battery case (1) has a hole (3) for discharging internal pressure, the peripheral portion of which protrudes toward the outside of the battery.
The heat-adhesive polyolefin resin (4) is outsert outside the hole (3) to form the battery case (1).
Is sealed, and a metal case (5) is covered over the resin to prevent gas permeation. Also, the working pressure of the safety mechanism is adjusted by adjusting the angle (θ) and the dimension (h) of the protrusions at the peripheral portion of the hole (3). The operating temperature range of the non-aqueous electrolyte described here is usually -20 ° C to 60 ° C. However, if the softening point of the heat-adhesive polyolefin resin is low, the safety mechanism may operate even under normal use. Further, if the softening point is high, even if the internal pressure rises as the battery temperature rises, the safety mechanism may not operate and the battery may burst.
Therefore, it is preferable to select a heat-adhesive polyolefin resin having a softening point of 90 to 150 ° C. In this way, in the case of internal short circuit and external short circuit, or when the internal pressure of the battery rises due to the temperature being forcibly raised from the outside, etc., the heat-adhesive polyolefin outserted around the internal pressure discharge hole (3) by the pressure. The system resin (4) comes off, and the internal gas is discharged to the outside of the battery case (1).

[0013]

As described above, according to the present invention, the battery case or the sealing plate is formed with a hole for discharging the gas inside the battery, with its peripheral edge protruding outward, and the hole is formed outside the hole. Since the heat-adhesive polyolefin resin is outsert so as to cover the protrusions and close the holes, and the case or the sealing plate is sealed, the battery safety mechanism that operates stably at a low pressure can be easily performed. It is possible to provide a battery with a safety mechanism that can be formed at low cost and that has long-term reliability in terms of hermeticity and airtightness.

[Brief description of drawings]

FIG. 1 is a sectional view showing a main part of a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a safety mechanism portion of FIG.

[Explanation of symbols]

 1 Battery Case 3 Holes 4 Thermal Adhesive Polyolefin Resin

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Naoshi Sudo, 333 Minorita, Matsudo City, Chiba Prefecture Toyo Takasago Dry Electric Battery Co., Ltd. Company Development Department (72) Inventor Yasumasa Mochizuki 333 Minoridai, Matsudo City, Chiba Toyo Takasago Dry Battery Co., Ltd.

Claims (1)

[Claims] 1. A battery case or a sealing plate, a peripheral edge of which projects outwardly to form a hole for discharging gas inside the battery, and the projection is covered outside the hole to close the hole. A battery with a safety mechanism in which the heat-adhesive polyolefin resin is outserted and the case or sealing plate is sealed.