梯次利用锂离子电池欧姆内阻测试方法研究

Research on testing method of ohmic resistance for Li-ion batteries echelon use

研究了欧姆内阻的三种测试原理和方法。在深入分析混合脉冲功率特性(HPPC)欧姆内阻测试方法的基础上,提出了梯次利用锂离子电池欧姆内阻测试的最佳采样点(放电下降沿,充电上升沿)和采样时间;建立了电化学阻抗模型,对不同直流偏置下的交流阻抗图谱进行了参数辨识,验证了欧姆内阻和直流偏置电流的不相关性,为电流转换法中100ms采样时间下测试欧姆内阻提供了理论依据;研究了基于电流转化法的欧姆内阻测试新方法,该方法在100 ms采样时间下,有效地减小了测试设备和数据采集响应误差的影响,并适当地减小了极化对欧姆内阻的影响,提高了欧姆内阻测试的准确性。

Three types of testing principles and methods of ohmic resistance were researched. Based on the in-depth analyses of hybrid pulse power characterization（HPPC） method for testing ohmic resistance, the optimal sampling points（the falling edge of discharge,the rising edge of charge） and sampling time for Li-ion batteries echelon use were proposed. Then, the electrochemical impedance model was established, and the electrochemical impedance parameters under different DC bias were identified, which not only verified the irrelevance between parameters of ohmic resistance and current, but also provided the theoretical basis of using 100 ms sampling time for current switching ohmic resistance testing method. Besides, the novel testing method of ohmic resistance based on current switching method was presented. Under the sampling time of 100 ms, this method effectively reduces the influence of errors caused by testing equipment and data acquisition response, and it also appropriately reduces the influence of polarization on the ohmic resistance, while improving the measurement accuracy of ohmic resistance.