锂离子电池阻抗参数的Arrhenius特性分析

Impedance Parameters Arrhenius Properties Analysis for Lithium Ion Batteries

考察了环境温度对18650型磷酸铁锂(LFP)电池和高镍三元(NCA)电池充电容量的影响,比较了2种电池的低温性能。对不同环境温度的满电状态电池进行电化学阻抗测试,根据等效电路拟合计算了电池的欧姆电阻值(R_s)、膜电阻值(R_f)和电荷转移电阻值(R_(ct)),并分析了各电阻与温度的特定关系,结果表明LFP电池的欧姆电阻和膜电阻在–10～25℃温度区间具有Arrhenius关系,电荷转移电阻在–10～50℃温度区间具有Arrhenius关系;NCA电池的膜电阻和电荷转移电阻在0～50℃温度区间具有Arrhenius关系。对比分析不同温度的固相离子扩散系数表明,LFP电池的固相离子迁移速率受低温影响较大,NCA电池的固相离子扩散过程受环境温度影响较小。

The influence of ambient temperatures on charging capacities of 18650 type LFP and NCA batteries were investigated, and the performance in low temperature was compared. The electrochemical impedance measurements were taken at various temperatures, the values of ohm, film and charge transfer resistances were confirmed according to equivalent circuits. The results show that as for LFP batteries, the ohmic resistance and film resistance are well meet the Arrhenius relations in the range of –10~25 ℃, however, in a wider range of –10~50 ℃ charge transfer resistance is well meet. However, as for NCA batteries, the film resistance and charge transfer resistance are complied with Arrhenius relations in range of 0~50 ℃. The comparison analyses of solid phase ion diffusion coefficient at different temperatures indicate that the ion diffusion rate of LFP battery is obviously affected by low temperatures, nevertheless, slightly affected for the NCA battery.