Aluminum alloy sheet for battery lid for molding integrated explosion-proof valve and production method therefor

Abstract

Provided are: an aluminum alloy sheet that is for a battery lid and that has an appropriate strength and excellent moldability and work-softening properties, wherein the aluminum alloy sheet can be used to mold an integrated explosion-proof valve that has less variations in working pressure and excellent cyclic fatigue resistance characteristics; and a production method for the aluminum alloy sheet. This aluminum alloy sheet is for a battery lid for molding an integrated explosion-proof valve, and is characterized by: having a compositional makeup which includes 1.05-1.50 mass% of Fe, 0.15-0.70 mass% of Mn, 0.002-0.15 mass% of Ti, and less than 0.03 mass% of B, the balance being Al and impurities, wherein the Fe / Mn ratio is limited to 1.8-7.0, the amounts of Si, Cu, Mg, and V, which are impurities, are limited to less than 0.40 mass%, less than 0.03 mass%, less than 0.05 mass%, and less than 0.03 mass%, respectively; having a tensile strength of 95 MPa or more and an elongation value of 40% or more; having a recrystallized structure; having a value (TS95-TS70) of less than -1 MPa, where TS70 represents the tensile strength after cold rolling is performed at a rolling-reduction ratio of 70%, and TS95 represents the tensile strength after cold rolling is performed at a rolling-reduction ratio of 95%; and having a value of elongation of 5.0% or more, after cold rolling is performed at a rolling-reduction ratio of 90%. Furthermore, the average crystal grain size of recrystallized grains in the recrystallized structure is preferably 15-30 mum.

Description

technical field [0001] The present invention relates to an aluminum alloy plate for a battery cover for forming an integrated explosion-proof valve used in square, cylindrical and other lithium-ion batteries and having a small working pressure deviation. Background technique [0002] In recent years, countries have imposed stricter regulations on automobile exhaust, and the production of electric vehicles, which are environmentally friendly vehicles, is rapidly expanding. Currently, the mainstream of secondary batteries used in electric vehicles is lithium-ion batteries. Lithium-ion battery casings come in various types such as square, cylindrical, and sheet-shaped. In the case of square and cylindrical shapes, aluminum alloy plates that can achieve weight reduction are drawn and processed. Or a shell obtained by thinning and deep drawing processing (also called DI processing). [0003] Thus, as a material for a battery case, development of an aluminum alloy plate having e...

AI Technical Summary

Problems solved by technology

The explosion-proof valve must work reliably, and the valve will automatically break when the internal pressure of the container exceeds the specified pressure, etc.

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