JPH06163079A - Non-aqueous electrolyte battery - Google Patents

Abstract

(57) [Summary] [Purpose] To ensure the safety of the battery during overcharge, short circuit, or heating due to the gas easily dissipating to the outside of the battery through the safety valve. [Structure] A sealed non-aqueous electrolyte battery having an electrode group composed of a wound positive electrode plate 11, a separator 12 and a negative electrode plate 13, in which an electrode pressing plate 15 made of a thermosetting resin is arranged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed non-aqueous electrolyte battery having an explosion-proof structure.

[0002]

SUMMARY OF THE INVENTION The present invention is a wound positive electrode, a separator,
In a sealed non-aqueous electrolyte battery having an electrode group consisting of a negative electrode, by disposing an electrode pressing plate made of a thermosetting resin, it is possible to prevent an explosive rupture that occurs during overcharge, short circuit, or heating. It was done.

[0003]

2. Description of the Related Art Recently, a secondary battery using a non-aqueous electrolyte such as a lithium battery or a lithium ion battery has been widely used in portable electronic devices and the like.

By the way, in the battery as described above, the power generating element housed in the battery may undergo a chemical change to increase the internal pressure and explosively burst.

For example, a non-aqueous electrolyte battery such as a lithium secondary battery is supplied with a current higher than usual to bring it into a so-called overcharged state, or a short circuit occurs due to misuse, resulting in a large current flow or erroneous flow. When heated, the electrolytic solution in the power generating element may be decomposed and gas may be generated.The gas fills the battery, the pressure in the battery increases, and finally the battery It may explode and explode.

Therefore, in order to prevent the above explosive explosion of the battery, as shown in FIG. 2, an explosion-proof safety valve is provided on the upper end of the outer can that also serves as the negative electrode terminal accommodating the power generating element. A device is provided (Utility model publication Sho 5
9-15398).

For example, the safety valve device shown in FIG. 2 is provided on the upper end portion of the outer can 1, that is, the sealing lid 2, has a lid plate 4 with a valve hole 3 narrowed, and a gas vent hole 5. The bent edge 6 of the lid plate 4 and the dish-shaped terminal plate 7 to be caulked and mounted.

The peripheral edge of the flexible thin plate 8 is sandwiched between the lid plate 4 and the dish-shaped terminal plate 7 or the like, and the valve hole 3 is always closed. The flexible thin plate 8 is a metal layer 81. It is composed of a composite member with the synthetic resin layer 82. 10 is
A blade piece that opposes the flexible thin plate 8 and is formed by bending a part of the terminal plate 7 inward.

When the internal pressure of the battery rises due to overcharging or the like and reaches a predetermined pressure, the flexible thin plate 8 is broken, and the gas in the battery is released into the atmosphere from the gas vent hole 5 through the valve hole 3 by the safety valve operation. Explosive rupture of the discharged battery is prevented in advance.

[0010]

However, even if such a safety valve device is used, in the battery having the electrode group consisting of the wound positive electrode 11, the separator 12 and the negative electrode 13 as shown in FIG. When the electrode group is deformed by the internal pressure and the valve hole 3 and the gas vent hole 5 are closed by the electrode group, gas is accumulated and the internal pressure increases, which may cause the battery to explode and explode.

The present invention has been made in view of the above points, and its purpose is to prevent overcharge, short circuit,
It is an object of the present invention to provide a non-aqueous electrolyte battery that can prevent explosive bursting that occurs during heating.

[0012]

According to the present invention, an electrode pressing plate made of a thermosetting resin is arranged in a sealed non-aqueous electrolyte battery having an electrode group composed of a wound positive electrode, a separator and a negative electrode. A battery is provided.

In a conventional sealed nonaqueous electrolyte battery having a wound electrode group, the battery may explode and burst during overcharge, short circuit, or heating. This is because when the decomposition gas of the electrolytic solution is discharged into the atmosphere through the valve hole 3 and the gas vent hole 5, the electrode group is deformed by the internal pressure of the decomposition gas, and the electrode hole and the gas vent hole 5 are separated by the electrode group. It was found that the battery was clogged, the gas was accumulated, the internal pressure was increased, and the battery explosively exploded.

As a result of studying a method of suppressing the deformation of the electrode group when the decomposed gas is generated and preventing the valve hole 3 and the gas vent hole 5 from being blocked by the electrode group, an electrode pressing plate made of a specific material is arranged. By fixing the group, it was found that when the safety valve operates during abnormal heat generation or abnormal gas generation, the gas can be smoothly dissipated outside the battery can and the battery safety can be secured without leading to phenomena such as rupture. It was

In the present invention, selection of the material of the electrode pressing plate is extremely important.

That is, the material of the electrode pressing plate must be a thermosetting resin. The present inventors have studied various materials including a thermoplastic super heat resistant resin, and found that a remarkable effect is exhibited only when the above thermosetting resin is used.

For example, when the thermoplastic super heat resistant resin was used, there was no problem in terms of electrical insulation, but when abnormal heat was generated, the resin was deformed and the function as a pressing plate was lost, resulting in The result is that the probability of the battery can bursting is high.

On the other hand, although studies were also conducted on metal materials, ceramic materials, etc., the former had a problem in terms of electrical insulation, and the latter had problems in terms of moldability and cost. The thermosetting resin referred to in the present invention is not particularly limited, but if one example is shown, phenol resin, unsaturated polyester resin, melamine resin, epoxy resin,
Examples thereof include alkyd resins and urea resins.

If necessary, the thermosetting resin may be reinforced with a reinforcing material such as glass fiber or talc.

In the present invention, there is no problem in using other means, such as arranging a pipe at the center of the electrode group, for the sake of further safety.

The present invention is effective regardless of the shape of the battery,
It can be applied to batteries of various shapes such as a cylindrical type, a flat elliptical type and the like.

According to the configuration of the present invention as described above,
Since the electrode group is fixed by the electrode pressing plate made of a thermosetting resin, even if the internal pressure in the battery increases due to overcharge, short circuit, or heating, the electrode group does not deform, and the valve hole 3 and the gas are prevented. The vent hole 5 is blocked by the electrode group, and it is possible to prevent gas from accumulating and increasing the internal pressure to explode the battery.

[0023]

EXAMPLES Next, examples of the present invention will be described with reference to FIG.

The non-aqueous electrolyte battery according to this embodiment is shown in FIG.
As shown in Fig. 3, the outer casing is composed of a cylindrical outer can containing a power generating element consisting of an electrolyte and an electrode group, and a sealing lid equipped with a safety valve provided at the upper end of the outer can. An electrode pressing plate 15 made of a thermosetting resin is arranged in the.

Hereinafter, description will be made on the basis of experimental results of a specific battery.

As the positive electrode plate, a composite oxide of lithium and manganese LiMnO ₂ to which a conductive material and a binder are added, applied on an aluminum substrate, dried, and made into a sheet shape is used, and a metallic lithium sheet is used as it is as the negative electrode plate.
A polyethylene microporous film as a separator was interposed to form a wound electrode group.

Next, the electrode group having a pipe arranged at the center is housed in an outer can made of stainless steel, an electrode pressing plate made of phenol resin is arranged on the electrode group, and caulking and sealing are carried out to obtain an outer shape of 17 m.
A cylindrical example battery having m, a height of 50 mm and a capacity of 700 mAh was produced. The electrolyte used was a mixed solvent of propylene carbonate and dimethoxyethane in which 1 mol of a solute of lithium phosphorus fluoride was dissolved.

At the same time, as a comparative example, a battery exactly the same as the example was manufactured except that the electrode pressing plate was not used.

Each of the produced batteries is charged,
A heating test was performed on a hot plate at 250 ° C.

As a result, the example batteries were tested 20 times.
In all of them, the gas due to the decomposition of the electrolyte was gently dissipated from the safety valve, ensuring safety. When the battery after the test was disassembled and examined, no evidence of deformation was found in the electrode group. Further, the electrode holding plate made of phenol resin was exposed to a high temperature of 400 to 500 ° C. at the maximum in the heating test, but no deformation such as cracking was observed.

On the other hand, in the comparative battery, 3 out of 20 batteries exploded explosively, and the sealing lid and electrode group were scattered from the outer can. Furthermore, when the batteries that did not undergo explosive rupture were disassembled and examined, partial blockages of valve holes and gas vent holes due to deformation of the electrode group were all found.

[0032]

According to the present invention configured as described above, the deformation of the electrode group due to the internal pressure of the decomposition gas of the electrolytic solution is suppressed, and the valve group and the gas vent hole are not blocked by the electrode group, so that the gas is accumulated. Gas can be smoothly dissipated to the outside of the battery through the safety valve, and the safety of the battery at the time of overcharge, short circuit or heating can be secured.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a battery including a safety structure according to an exemplary embodiment of the present invention.

FIG. 2 is a cross-sectional view of a conventional example battery.

[Explanation of symbols]

 1 outer can 2 sealing lid 3 valve hole 4 lid plate 5 gas vent hole 6 bent edge 7 terminal plate 8 flexible thin plate 9 insulating packing 10 cutting edge 11 positive electrode plate 12 separator 13 negative electrode plate 14 pipe 15 electrode pressing plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsuhiko Inoue 1-3-1, Yokou, Kawasaki-ku, Kanagawa Prefecture Asahi Kasei Kogyo Co., Ltd. (72) Inventor Yoshiaki Asami 3, 4--10 Minamishinagawa, Shinagawa-ku, Tokyo No. Toshiba Battery Co., Ltd. (72) Inventor Hiroyoshi Nose 3-4-10 Minamishinagawa, Shinagawa-ku, Tokyo Inside Toshiba Battery Co., Ltd.

Claims (1)

[Claims] 1. A sealed non-aqueous electrolyte battery having an electrode group consisting of a wound positive electrode, a separator and a negative electrode, wherein an electrode pressing plate made of a thermosetting resin is arranged.