JPH0641338Y2 - Cylindrical battery - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> This invention is a cylinder formed by sealing the opening of a cylindrical battery can containing a power generation element in combination with a terminal plate, an insulating gasket and the like. Shaped battery.

<Prior art> For cylindrical batteries such as spiral type lithium batteries, inside-out type lithium batteries, and cylindrical Ni-Cd storage batteries, the beading part formed in the opening of the cylindrical battery can that houses the power generation element is used. By supporting an annular insulating gasket, placing a sealing member such as a terminal plate on this insulating gasket, and sandwiching this insulating gasket between the battery can opening caulked inside and the terminal plate peripheral edge. The form of sealing the battery is widely used.

With these batteries, if the internal pressure of the battery rises abnormally due to a large amount of gas generated inside the battery due to an external short circuit or overcharging, this abnormal internal pressure is released to the outside of the battery by the explosion-proof mechanism installed at the opening of the battery can. The structure is used to prevent deformation and rupture of the battery.

As an explosion-proof structure of this type, for example, in the case of a spiral lithium battery, as shown in FIG. 3, a sealing plate made of a thin metal is used.
11, and a cutting edge 12a and a gas vent hole facing the sealing plate 11.
The terminal plate 12 provided with 12b is provided in the opening of the battery can 13, and the sealing plate 11 bulging due to the abnormal internal pressure of the battery is penetrated by the cutting blade 12a to make a hole, and the abnormal internal pressure is supplied to the battery through this hole. Designed to escape to the outside.

On the other hand, especially in the case of a spiral lithium battery, there is a risk that the battery temperature will rise rapidly due to heat generation from the inside of the battery due to an external short circuit, and the battery will ignite. PTC element is installed between
A configuration that limits the current at the time of a short circuit by the TC element may be used.

<Problems to be solved by the invention> However, in the battery of the above type in which the insulating gasket is placed on the beading portion formed in the opening of the battery can, the power generating element must be provided below the beading portion. Furthermore, if the battery can opening is provided with the above explosion-proof structure, a large internal space is provided in that part, so that the capacity of the power generation element that can be accommodated in the battery is suppressed and the discharge capacity is limited. Will be done.

In particular, when the PTC element is further provided as described above in order to suppress heat generation when the battery is externally short-circuited, this tendency is further enhanced.

This device has high safety because it can prevent explosion or rupture due to external short circuit or charging by storing the above explosion-proof structure and PTC element in the battery can opening with good capacity efficiency. Moreover, it is an object of the present invention to provide a tubular battery which has a high capacity and a small loss of internal volume.

<Means for Solving the Problems> In the cylindrical battery of the present invention, a metal thin plate or a metal-synthetic resin laminate thin plate is sandwiched by the outer peripheral folded portion of a metal plate having a through hole in the center, and the metal plate Place the outer peripheral part of the terminal plate having the gas venting hole and the cutting edge on the upper outer surface of the outer peripheral folded part through the ring-shaped PTC element, and further install the metal plate, the PTC element and the outer peripheral part of the terminal plate on the insulating gasket. Via the through, the battery can containing the power generation element is integrally formed or welded to the inner peripheral end of the sealing plate provided by seam welding at the opening, and is sandwiched by members having a U-shaped cross section. To do.

As the metal thin plate, a stainless thin plate, an aluminum thin plate, a titanium thin plate, or the like can be used. As the metal-synthetic resin laminate thin plate, those obtained by laminating or coating the surface of these metal thin plates with synthetic resin may be used.

In addition, the metal thin film or the metal-synthetic resin laminate thin plate and the metal plate may be bonded to each other in the sandwiched portion by hot melt resin.

<Operation> A metal thin film or a metal-synthetic resin laminate thin plate and a terminal plate are formed in a member having a U-shaped cross section provided at the inner peripheral end of the sealing plate provided at the opening of the battery can as described above. By forming the sealing portion provided with the explosion-proof structure and the PTC element, the explosion-proof structure and the PTC element can be stored in the opening of the battery can with high capacity efficiency, and the loss of the internal volume of the battery can be suppressed to be small.

When the internal pressure of the battery rises due to overcharging, etc., the above-mentioned explosion-proof structure limits the short-circuit current by the PTC element when the battery heats up due to an external short circuit. it can.

<Examples> Examples will be described below.

In FIG. 1, the outer peripheral rising portion of a plate-shaped annular sealing plate 3 made of a stainless steel plate having a thickness of about 0.2 mm is provided around the opening of a bottomed cylindrical battery can 2 accommodating the power generation element 1. The periphery of the is welded continuously by seam welding, welding or resistance welding. The inner peripheral edge of this sealing plate 3 has a thickness of 0.25 mm.
Similarly, the inner peripheral edge of the member 4 having a U-shaped cross section using the stainless thin plate is welded. The member 4 having a U-shaped cross section may be formed integrally with the inner periphery of the sealing plate 3 by bending the inner peripheral portion of the sealing plate 3.

On the other hand, the outer peripheral folded-back portion 5b of the metal plate 5 made of a stainless steel plate having a thickness of 0.25 mm having the through hole 5a in the center, the synthetic resin sealing body 6, and a metal made of a polypropylene-aluminum laminated film having a thickness of 50 μm. -The outer peripheral portion of the synthetic resin laminate thin plate 7 is clamped. The lower surface of the metal-synthetic resin laminate thin plate 7 and the outer peripheral folded-back portion 5b are bonded together by hot melt resin.

Further, on the upper outer surface of the outer peripheral folded-back portion 5b of the metal plate 5,
Outer circumference of the terminal plate 9 made of a 0.25 mm-thick stainless steel thin plate having a gas vent hole 9a and a cutting edge 9b through a ring-shaped PTC element 8 having a thickness of approximately 0.4 mm, and the surface of the terminal being nickel-plated. Section is placed. Further, the metal plate 5, the PTC element 8, and the outer peripheral portion of the terminal plate 9 are pressed and sandwiched by the above-mentioned member 4 having a U-shaped cross section through the insulating gasket 10.

The PTC element 8 has a thickness of about 0.4 mm, which is formed by providing a metal plating layer or a thin metal foil on both surfaces of a conductive resin layer having a positive temperature coefficient resistance characteristic, the resistance value of which increases sharply as the temperature rises. You can use the one.

Then, an AA size spiral lithium battery (the battery of the present invention) was produced with the battery can opening having the above structure. On the other hand, an AA-sized cylindrical lithium battery (conventional battery) was prepared in the same manner except that the battery can opening had the structure shown in FIG. With respect to these batteries, each battery was externally short-circuited, and the time change of the battery surface temperature (° C.) after the short circuit was examined.

Figure 2 shows this result. In the conventional battery shown by the dotted line, the battery temperature is 160 ° C at 5 to 6 minutes after the short circuit.
In contrast to the above, the battery ignited, but in the case of the battery of the present invention shown by the solid line, the temperature rise of the battery was slight, and the battery temperature was suppressed to about 70 ° C even 10 minutes after the short circuit. .

By the way, in the case of the battery of the present invention, the height from the sealing plate 3 to the terminal plate 9 is only 2 to 2.5 mm. On the other hand, in the conventional battery, the height from the sealing plate 11 to the terminal plate 12 is 3.5 to 4 mm, and since the beading portion for mounting the insulating gasket 14 is provided, the height is further increased to about 1.5 to 2 mm. I will be lost.

Therefore, if the opening of the battery can has the structure of the battery of the present invention, the height of the power generating element can be set to about 3 mm higher than that of the conventional battery, so that the storage amount of the power generating element can be increased accordingly. That is, in the battery of the present invention, the storage volume of the power generation element that can be stored inside the battery can is about 10% larger than that of the conventional battery, and the discharge performance can be improved accordingly.

<Effects of the Invention> As described above, according to the cylindrical battery of the present invention, it is possible to reliably prevent the burst heat generation of the battery when the battery is externally short-circuited or charged, and to provide an explosion-proof structure and a PTC element for the battery. Since it can be stored in the can opening portion with high capacity efficiency, the loss of the internal volume of the battery can be suppressed to a small extent, and the storage amount of the power generation element can be increased accordingly.

Besides, since the sealing portion is configured by sandwiching the outer peripheral portion of the metal plate or the like by the member having a U-shaped cross section, the degree of freedom in designing the sealing portion is increased, and the sealing portion can be assembled as one part. As a result, there is an effect that the member can be sufficiently tightened in the sealing portion.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an essential part of the battery of the embodiment, FIG. 2 is a graph showing a time-dependent change of the battery surface temperature when the battery is short-circuited to the outside, and FIG. 1,15 …… power generation element, 2,13 …… battery can, 3,11 …… sealing plate,
5 ... Metal plate, 8 ... PTC element, 9,12 ... Terminal plate, 10,14
...... Insulation gasket, 1a, 15a ...... Lead plate.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Yoshiro Harada, 5-16-11 Shimbashi, Minato-ku, Tokyo Fuji Electric Chemical Co., Ltd. (72) Masanori Nakanishi 5-36-11 Shinbashi, Minato-ku, Tokyo Fuji Electrochemical Co., Ltd. (72) Inventor Hidetetsu Nagura, 5-16-11, Shimbashi, Minato-ku, Tokyo Fuji Electric Chemical Co., Ltd. (56) References: Development 64-65 (JP, U) Development 59- 3476 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A metal thin plate or a metal-synthetic resin laminate thin plate (7) is sandwiched by an outer peripheral folded-back portion of a metal plate (5) having a through hole (5a) in the center, and an outer peripheral folded-back portion of the metal plate. Ring-shaped on the outer surface of
Gas vent hole (9a) and cutting edge (9) through PTC element (8)
A battery in which the outer peripheral portion of the terminal plate (9) having b) is placed, and further the metal plate, the PTC element and the outer peripheral portion of the terminal plate are accommodated with the power generation element (1) through the insulating gasket (10). It is characterized in that it is sandwiched by a member (4) having a U-shaped cross section, which is integrally formed or welded to an inner peripheral end of a sealing plate (3) provided by seam welding at an opening of a can (2). Cylindrical battery.