Benign-to-malignant transition in external short circuiting of lithium-ion batteries

External short circuiting (ESC) is a main source of battery faults. However, the ESC damage mechanism and its evolution process are unclear, resulting in difficulties in safety management. Here, we report the impact of different ESC durations on battery perfor-mance and divide the ESC process into four stages. The analysis re-veals that there is a benign regime in which the ESC effect is comparable to nominal charge-discharge cycling. When ESC duration is close to a critical time, there is a benign-to-malignant transition. The critical time corresponds to the inflection point at the end of battery current curve, which reflects heating-induced membrane melting and contraction that distorts the jellyroll. The critical time surface under various conditions is established and the center tem-peratures of the critical time and battery completely failure are dis-closed, paving the way for fault diagnosis and using benign ESC in a controlled fashion.

Automated summary

This study reports the impact of different ESC durations on battery performance and divides the ESC process into four stages. It reveals a transition from benign to malignant when the ESC duration is close to a critical time. The establishment of the critical time surface and the disclosure of center temperatures of the critical time and battery failure pave the way for fault diagnosis and controlled benign ESC.