能量型磷酸铁锂动力电池直流内阻测试及分析

Experimental Analysis of Internal Resistance of Energy-Type LiFePO_4 Power Batteries and Its Influencing Factors

以1.5 A·h圆柱形磷酸铁锂电池为研究对象,采用HPPC测试法在常温环境下进行了不同电流倍率、不同脉冲时间和不同电流方向的试验验证,分析了3种因素对直流内阻测试结果的影响,得到了常温环境下充电态/放电态欧姆内阻和极化内阻的变化规律。实验结果表明:欧姆内阻在数值上远大于极化内阻;极化内阻比欧姆内阻对SOC更敏感;极化内阻随着脉冲时间长度的增加而增加,且这种增加趋势随着脉冲时间长度的增加逐渐减小;电池充放电状态对欧姆内阻的影响较小,对极化内阻的影响较大;电流倍率对欧姆内阻的测量结果影响较小,极化内阻随着电流倍率的增加呈线性减小。

Taking the 1. 5 A·h cylindrical LiFePO_4 battery cell as the research object,this paper investigated the characteristics of ohmic and polarization internal resistances at room temperature using the HPPC method. Meanwhile,influences of the pulse current magnitude and time on experimental results are evaluated. Experimental results show that ohmic resistance is much larger than polarization resistance and polarization resistance is more sensitive to SOC than ohmic resistance. With the rise of pulse current time,polarization resistance also increases. And the increasing range decreases with the pulse current time rising. Charging/discharging status has a much lower influence on ohmic resistancethan polarization resistance. In addition,polarization resistance increases in a linear relationship with the current rate,while the current rate has relatively little influence on ohmic resistance.