Battery casing and battery casing safety valve forming method

Abstract

The invention provides a forming method for the safety valve of an aluminum alloy lithium-ion battery casing. The method utilizes punching to form in shape with high precision and working efficiency. As a safety valve (2), one part (3a) of the battery casing (1) wall (3) is punched to form a cup shaped protruding part which protrudes externally. The top of the safety valve (2) is a flat thin film (4). The circumferential part (4a) of the thin film top (4) crosses the side wall (6) of the protruding part facing the thin film top and is integrated to the battery casing (1) wall (3) as a whole unit.

Description

technical field [0001] The present invention relates to a Li ion battery case provided with a safety valve for releasing internal pressure and a method for forming the safety valve of the Li ion battery case. Background technique [0002] Lithium-ion rechargeable batteries (Li-ion batteries) are widely used as power sources for mobile phones, notebook computers, and the like. In the plates constituting the Li ion battery case (hereinafter simply referred to as the battery case), many metals are used including the lid, and patent documents 1 to 3 disclose battery cases using iron alloys such as SUS, Patent Documents 4 to 9 disclose battery cases using aluminum alloys. In particular, when the cover and the main body of the battery case are made of a formed product formed by stamping an aluminum alloy plate (cold-rolled plate) material, it is difficult to achieve the desired results in terms of corrosion resistance, weight reduction, workability, and cost. is advantageous. ...

AI Technical Summary

Problems solved by technology

Therefore, a large forming force is required, the difficulty of processing becomes high, and the wall thickness of the thin film part 24 cannot be stabilized such as uniformity and constant in the entire area where it extends, resulting in fluctuation (variation) of the wall thickness.

As a result, it is difficult to ensure the accuracy or shape accuracy of the residual thickness of the small thickness (wall thickness) of the notch portion and the thin film portion that are required as the safety valve 20 to form the groove for breaking.

[0029] In particular, compared to the iron alloys and steels such as SUS and the like, which are relatively high in rigidity, in the soft aluminum alloy plate with a low elastic coefficient, in the press forming, especially the thin thickness (wall thickness) is formed. , the accuracy of the remaining thickness, or the accuracy of the shape of the groove becomes very difficult

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