Square cell case forming method

Abstract

The invention provides a square cell case forming method capable of efficiently forming an aluminum alloy plate into a high flatness square cell case with high precision; the method comprises the following steps: drawing the aluminum alloy plate so as to form a first square cylinder (2), wherein a part of the periphery of a side wall portion (2a) of the first square cylinder forms an oblique surface (2f); the bottom (2d) of the first square cylinder (2) serves as the bottom of the cell case; continuously drawing or fine processing so as to form the final square cell case, wherein the plate thickness of the side wall becomes under 60% of that of the aluminum alloy plate.

Description

technical field [0001] The present invention relates to a method of forming a prismatic battery case which is a case of a Li ion battery or the like. Background technique [0002] Lithium-ion rechargeable batteries (Li-ion batteries) are widely used as power sources for mobile phones, notebook computers, electric vehicles, hybrid vehicles, and the like. [0003] Metals are often used for plates constituting the Li ion battery case (hereinafter simply referred to as the battery case), including the lid, and iron alloys such as stainless steel and aluminum alloys are used. In particular, when the cover and the main body (can) of the battery case are formed of a formed product formed by stamping an aluminum alloy plate (cold-rolled plate) material, it is important in terms of corrosion resistance, weight reduction, processability, and cost. advantageous. [0004] As the shape of the above-mentioned battery case, as a battery case having a square cross-sectional shape with hig...

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Problems solved by technology

However, in the above-mentioned forming method, there are problems as follows: a plurality of expensive molds are required due to the existence of a plurality of processes; an increase in equipment cost caused by a large continuous automatic press machine; machine processing without being able to increase the stamping speed, resulting in low productivity, etc.

[0017] However, according to the above-mentioned forming methods of Patent Document 2 and Non-Patent Document 1, it is still difficult to form an aluminum alloy plate into a prismatic battery case with high flatness by using the DI forming method of continuously drawing and thinning. Ensure plate thickness and shape accuracy

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