JPH0682547B2 - Battery pack - Google Patents

Description

TECHNICAL FIELD The present invention relates to a battery pack including at least one organic electrolyte battery and a battery case accommodating the battery.

(B) Conventional technology Organic electrolyte batteries use light metals such as lithium and sodium as the negative electrode active material, manganese dioxide, carbon fluoride, etc. as the positive electrode active material, and use an organic electrolyte solution composed of an organic solvent and a solute. However, it has the advantages of high energy density and little self-discharge. The battery is housed in a battery case and is used as a battery pack for the power supply of portable devices and the power supply for memory backup.

By the way, due to recent remarkable improvements in battery technology, battery design may be carried out by setting the maximum battery usage temperature to a high temperature of about 100 ° C, and accompanying this, improvement in heat resistance is required for the case itself that houses the battery. ing.

The conventional case is formed of, for example, ABS (acrylonitrile-styrene-butadiene copolymer), PS (polystyrene), PC (polycarbonate), or the like.

C. Problems to be solved by the invention ABS and PS described above are heat resistant (UL temperature index: Unde
The maximum continuous operating temperature specified by rwriters Laboratories (USA)] is 60 to 80 ° C, which is lower than the maximum operating temperature of the battery, which is not sufficient as the quality of the case originally intended to protect the battery. Although PC can be said to have a high heat resistance temperature of 120 ° C, which is sufficient, the resistance to organic electrolytic solution is poor, so if the organic electrolytic solution leaks from the battery inside the case, the part of the case that comes in contact with the organic electrolytic solution will be eroded. It causes swelling, dissolution or solvent cracking, which adversely affects peripheral equipment. Incidentally, AB
It can be said that S and PS have the same resistance to organic electrolyte as those of PC.

D Means for solving the problem A modified polyphenylene oxide resin containing 10 to 40% by weight of styrene is used as a battery case material.

E. Actions Figure 1 shows the heat resistance temperature, the spiral flow length, and the weight change rate by the electrolytic solution immersion test with respect to the amount of styrene added to the modified polyphenylene oxide resin.

As shown in Fig. 1, when the amount of styrene added exceeds 40% by weight, the heat-resistant temperature becomes 100 ° C or less, which is unsuitable as a battery case as described above, and the weight change rate rapidly increases in the electrolyte immersion experiment. It can be seen that the erosion increases at the beginning.

On the other hand, if the addition amount of styrene is less than 10% by weight, the spiral flow length becomes short, the injection molding processability deteriorates, and the molding process becomes difficult.

The weight change rate indicates the weight change before and after immersion of the material in a mixed solvent of dimethoxyethane and tetrahydrofuran at 60 ° C. for 7 days. The spiral flow length is maintained at 60 ° C in a mold with spiral grooves, and the resin is injected into the spiral grooves under the conditions of a cylinder temperature of 240 ° C and an injection pressure of 1320kg / cm ² , and the distance the resin flows. Indicates
The longer the distance, the better the moldability.

It is understood from FIG. 1 that the addition amount of styrene is preferably in the range of 10 to 40% by weight.

F. Examples Table 1 shows polyphenylene oxide containing 25% by weight of styrene.
A test piece of the modified polyphenylene oxide (modified PPO) of the present invention, which was added and copolymerized, and conventional ABS, PS and
The rate of change in weight and the appearance state of each test piece of PC in an electrolyte immersion test are shown in comparison. In this case, the electrolytic solution immersion test was carried out under the conditions of immersion at 20 ° C. for 10 days using an organic electrolytic solution prepared by dissolving lithium perchlorate in a mixed solvent of propylene carbonate and dimethoxyethane.

It can be seen from Table 1 that the modified PPO has excellent organic electrolyte resistance.

FIG. 2 is an exploded perspective view of the battery pack according to the present invention,
(1) and (2) are split battery cases made of modified polyphenylene oxide containing 25% by weight of styrene, and one case (1) has a pair of notches (3) at the upper end surface.
(3) is formed, and the other case (2) is provided with protrusions (4) and (4) that fit into the cutouts (3) and (3).

When assembling the battery pack, the pair of organic electrolyte batteries (6) and (6) connected in series by the connecting piece (5) are housed in the recess (7) of the one case (1), and then the terminal fitting (8).
One end (8) '(8)' of (8) is spot welded to the terminal portion of the corresponding battery. Then, the terminal fittings (8) and (8) are locked by notches (3) and (3) provided on the upper end surface of one case (1) and through holes (9) and (9) provided on the side surfaces, After fixing, the other case (2) is covered and the joint portion of the split case is ultrasonically welded to obtain a completed battery pack. Incidentally, the pair of batteries (6) and (6) have at least one of the batteries covered with an insulating tube in order to prevent a short circuit.

Effect of the Invention As described above, according to the present invention, the modified polyphenylene oxide containing 10 to 40% by weight of styrene used as the material of the battery case is extremely stable to the organic electrolytic solution, so that it is possible to remove the organic compound from the battery during abnormal conditions. Even if the electrolyte leaks out, there is no inconvenience that the case dissolves or swells and cracks, and it is possible to minimize damage to peripheral equipment, and the heat resistance is 100 ° C or more in temperature index. Since it has a high temperature, it is possible to obtain a battery pack excellent in stability without deterioration of the case even when used under high temperature conditions, and its industrial value is extremely large.

[Brief description of drawings]

FIG. 1 is a diagram showing the relationship between the amount of styrene added to the modified polyphenylene oxide and various physical properties, and FIG. 2 is an exploded perspective view of the battery pack. (1) (2) …… Battery case, (3) (3) ……
Notch, (4) (4) ... Projection piece, (5) ... Connection piece,
(6) (6) ... organic electrolyte battery, (8) (8) ... terminal fittings, (9) (9) ... through holes.

Claims (1)

[Claims] 1. At least one organic electrolyte battery and a battery case accommodating the battery, wherein the case is made of a modified polyphenylene oxide resin containing 10 to 40% by weight of styrene. Battery pack to be used.