基于单频阻抗的锂离子电池热失控分级预警

Thermal runaway graded warning of Li-ion battery based on single-frequency impedance

潜在的热失控风险,特别是过充电,可能会引发锂离子电池的安全事故。以电化学阻抗谱(EIS)为基础,采用单频阻抗X_(1Hz)和X_(400Hz)实现电池内部阻抗的实时检测。在不同充电倍率、环境温度和健康状态下进行验证,特征阻抗表现出很好的稳定性。基于X_(1Hz)和X_(400Hz)的单频阻抗,提出一种热失控安全分级预警方法,并验证该方法的可靠性。该方法的最后一级预警可在热失控前5 min以上发出安全预警。

The potential risk of thermal runaway,especially overcharging,may lead to safety accidents of Li-ion battery.Based on electrochemical impedance spectroscopy(EIS),the real-time detection of internal battery impedance is achieved by employing single-frequency impedance at X_(1Hz)and X_(400Hz).After validation under different charging rates,environmental temperatures and states of health,the characteristic impedance demonstrates remarkable stability.Utilizing single-frequency impedance at X_(1Hz)and X_(400Hz),a thermal runaway safety classification and warning method is proposed,its reliability is verified.The final-stage warning of this method can issue a safety warning more than 5 min before thermal runaway.