高温下NCA三元锂离子电池循环性能的研究

A study on the performance of NCA Li-ion batteries at high temperature

研究了高温(60℃)与室温(25℃)条件下商品化NCA三元锂离子电池的循环特性,并分析了电化学阻抗谱随循环周数的变化规律,进而通过扫描电镜表征了正负电极表面形貌。结果表明,在高温下电池容量衰减和阻抗增加明显快于室温。扫描电镜表明,不同温度循环之后正极的表面形貌变化的差别并不显著,而石墨负极表面结构在高温下变化明显。以上结果说明,温度是影响电池循环性的重要因素,高温会使负极界面发生较大变化,阻抗增加,最终导致电池容量迅速衰减。

In this study, the performance of commercial NCA Li-ion batteries（LIBs） was studied at 25℃ and 60℃ by galvanostatic cycling and electrochemical impedance spectroscopy（EIS）. The morphologies of anode and cathode at different cycles were characterized by scanning electron microscope（SEM）. The results demonstrate that the capacity fading and EIS increase of the batteries are much faster at high temperature. The SEM images of the cycled electrodes at different temperatures exhibit that the cathode surfaces are almost the same but the anode surface is collapsed at high temperature. The results above suggest that temperature affects the performance significantly, and high temperature will lead to an anode surface collapse, an EIS increase, and eventually battery performance degradation.