Aluminum alloy plate for battery case with improved laser solder ability

Abstract

The invention provides an aluminum alloy plate used for battery case cover with excellent laser weldability capable of obtaining fine molten state even in low power output. The aluminum alloy plate is characterized in that it is formed by the aluminum alloy containing 1.4%-2.0% of Fe, less than 0.3% of Si, less than 0.2% of Cu, less than 0.2% of Mg, Al and other unavoidable impurities; while more than 40 intermetallic compounds between 2[mu]m and 5[mu]m exist in per 10000[mu]m<2> in the matrix.

Description

technical field [0001] The present invention relates to an aluminum alloy plate having excellent processability and laser weldability, which is suitable as a case cover of a lithium ion battery used in a mobile phone or a notebook computer. Background technique [0002] Light weight is strongly required for components assembled in mobile phones and notebook computers. Therefore, Al-Mn-based A3003 aluminum alloy plates have begun to be used instead of steel plates or stainless steel plates in lithium-ion battery case materials. [0003] In the prismatic battery case formed by combining multiple processes of drawing and thinning, the Al-Mn-based A3003 aluminum alloy can make the case thinner while maintaining a beautiful surface state with luster. chemicalized raw materials. The thinning of the wall is directly related to the increase of the internal volume, and is an important factor in achieving high capacity of the battery characteristics. The prismatic battery case is sea...

AI Technical Summary

Problems solved by technology

[0008] If the above materials are used as the battery case cover material, it is advantageous from the viewpoint of laser weldability, but since the material strength is higher than that of pure aluminum-based alloys, it is difficult to impart explosion-proof performance during molding

In addition, when alloys containing a large amount of Fe and Mn are used, coarse intermetallic compounds are likely to be formed during casting, and if such coarse intermetallic compounds exist in the molded part that imparts explosion-proof performance, they will become the origin of cracks. , is not ideal

[0009] An aluminum alloy plate for a battery case with 0.4% to 0.6% of Mn and 1.15% to 1.35% of Fe as main components has also been proposed (Japanese Patent Laid-Open No. 2007-107048), which exhibits excellent explosion-proof performance, but The specific characteristics of laser weldability are not clear, and the aluminum alloy plates in the above proposals are used as materials for lithium-ion battery case covers, and none of them have the characteristics that must be satisfied.

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