Warning lithium-ion battery thermal runaway with 4-min relaxation voltage

The continued growth of installed lithium-ion battery capacity is accelerating low-carbon energy constructions. However, the concern about battery thermal runaway (TR) spreads due to multi-scale applications of both nickel‑cobalt‑manganese (NCM) ternary lithium-ion batteries and lithium‑iron-phosphate (LFP) batteries, which raises the necessity of identifying battery internal short circuit (ISC) and warning TR. Although various TR warning methods have been proposed, the extra facility requirement and large computational cost hinder their applications in commercial battery scenarios. In this study, focusing on warning TR through lithium-ion battery ISC identification, we derive the correlation between relaxation voltages of ISC battery and normal battery, then a simple but effective approach, i.e., using battery relaxation voltage to obtain battery short-circuit resistance evolution during TR developing process, is proposed to warn TR in both NCM and LFP batteries. With battery ISC substitute experiments and mechanical abuse tests, the performance of proposed method in four brands batteries with different electrode materials and shapes is validated. Furthermore, the proposed method shows great adaptations to ambient temperature and current rate, which can realize ISC detection and TR warning with 4-min relaxation information from practical electric vehicles and energy storage stations.