多孔铝箔改善锂离子电池的针刺安全性

Improving nail penetration safety of Li-ion battery by porous Al foil

针刺热失控的主要热量来源是铝-负极短路,采用多孔铝箔来改善针刺安全性。多孔铝箔上的微孔可轻微削弱力学性能,使抗拉强度降低17%,断裂伸长率降低73%,导致针刺时形成的铝劈锋容易破裂和脱落,进而使得针刺内短路引起的焦耳热被抑制。微孔对锂离子电池的直流内阻、高倍率放电容量和循环性能等没有明显影响。

The main heat source of nail penetration thermal runaway was short-circuit caused by Al-anode,the porous Al foil was used to improve the nail penetration safety.The micro-pores on the porous Al foil lightly weakened the mechanical property,with tensile stress decreased 17%and break elongation decreased 73%,which induced that the Al burr was apt to fail off and break up during nail penetration.Therefore,the Joule heat generated by internal short-circuit was suppressed.The direct current internal resistance,discharge capacity at high rate and cycle performance of Li-ion battery were not apparently affected by the micro-pores.