正弦纹波电流对锂电池快充性能影响的研究

Study on Lithium Battery Fast Charge Performance with Ripple Charging Current

正弦纹波电流(SRC)充电对锂离子电池充电性能有一定改善,但已有的SRC充电研究均基于1C及以下的直流倍率,与直流充电相比没有取得显著的优化。为适应市场快速充电需求,本文首次探究了2C高倍率SRC快充对锂电池循环寿命的性能影响。通过对不同交流频率、振幅工况的循环寿命实验后的电池容量、内阻、温升和容量增量(IC)分析表明,尽管所提出的SRC快充会因为电流有效值变大导致温升高于直流,但电池寿命性能却显著优于直流;并在交流振幅为3C(AC/DC=1.5)、交流频率高于特征频率(825 Hz)工况时寿命性能达到最优。其中,10 kHz频率工况在100个循环后,电池容量衰减和活性物质损失(LAM)分别比直流降低了70.37%、59.6%;200个循环后内阻增量仅为直流的1/3.51,容量仅衰减51.17%,比直流延长251%的使用寿命。

Sinusoidal ripple current(SRC)charging has some performance optimization for lithium-ion battery charging,but existing studies on SRC charging are based on DC ratios of 1C and below,with no significant optimization compared with DC charging.In order to meet the market demand for fast charging,the effect of 2C high rate SRC fast charging on the cycle life of lithium batteries is studied in this paper for the first time.The analysis of battery capacity,internal resistance,temperature rise and increment capacity(IC)after cycle life experiment with different AC frequencies and amplitude shows that although the temperature rise of the proposed SRC fast charging is higher than that of DC due to the increase of current RMS,the battery life performance is significantly better than that of DC.The optimal performance is achieved when the AC amplitude is 3C(AC/DC=1.5)and the AC frequency is higher than the characteristic frequency(825 Hz).After 100 cycles at 10 kHz frequency,the battery capacity loss and loss of active material(LAM)is reduced by 70.37% and 59.6% compared with DC respectively.After 200 cycles,the internal resistance increment is only 1/3.51 of DC,with the capacity fading by only 51.17%,and the useful life 251%longer than DC.