低温搁置对锂离子电池性能的影响

Effect of low-temperature storing on the performance of Li-ion battery

了解低温搁置对电池循环性能及老化机制的影响,对锂离子电池在低温环境的运行管理很重要。在-40℃和25℃下搁置电池,并以1.00 C倍率在2.30~3.65 V进行充放电,重复上述操作15次。通过健康状态(SOH)、电化学阻抗、微分电压及容量增量曲线等性能参数,对锂离子电池的老化行为进行分析。低温搁置对电池SOH有一定影响,与对照组相比,平均容量保持率下降了2.04个百分点,首次库仑效率为97.4%。低温搁置后的电池欧姆阻抗和电荷转移阻抗增大。分析微分电压和容量增量曲线发现,电池内部活性物质和活性Li+损失是造成容量衰减的主要原因。

Understanding the effects of prolonged low-temperature storing on battery cycle performance and aging mechanisms is important for the operation and management of Li-ion battery in low-temperature environments.The batteries are set aside at-40℃and 25℃and are subjected to charge-discharge at 1.00 C rate in 2.30-3.65 V,the above operation is repeated 15 times.The aging behavior of Li-ion battery is analyzed by parameters such as state of health(SOH),electrochemical impedance,differential voltage and incremental capacity curves.Low-temperature storing has a certain influence on SOH of the battery,compared with the control group,the average capacity retention is decreased by 2.04 percentage points,the initial Coulombic efficiency is 97.4%.The Ohmic impedance and charge transfer impedance of the battery increase after low-temperature storing.By analyzing the differential voltage and incremental capacity curves,it is found that the loss of active material and active Li+inside the battery are the main causes of capacity degradation.