A Fast Identification Method for Internal Short-Circuit Resistance in Lithium-Ion Battery Based on Voltage Drop

Internal short circuit fault is a latent safety hazard in lithium-ion batteries. Fast and reliable fault diagnosis methods are crucial for ensuring their safety. Reports of actual internal short circuit fault events and conclusions from numerous studies indicate that such faults cause a rapid drop in battery voltage following the fault. Through analyzing the voltage drop based on the battery equivalent circuit model, a fast internal short circuit resistance identification method is proposed, achieving identification within seconds. Various substitute internal short circuit fault experiments show that the proposed method features fast identification speed, accurate identification precision, and applicability to all operating conditions. If the battery chemistry and operating conditions are not distinguished, the relative errors are within 10%. Whereas, for the NCM battery under charging process, the errors can be kept within 1%. The Cramer-Rao lower bound theory explains the differences in identification errors across various battery chemistries and operating conditions. Finally, the nail penetration experiment provides demonstrative support for the practical application of the proposed method.