Overcharge Behavior and Early Warning Analysis of LiNi0.5Co0.2Mn0.3O₂/C Lithium-Ion Battery with High Capacity

High-power lithium ion batteries have become the development focus of electric vehicles and large-scale energy storage devices. But it is also particularly critical to further study their hazardous properties under abuse conditions because higher capacity is more catastrophic. In this study, overcharge tests of 43 Ah cubic lithium ion batteries with different charge rates are conducted to study the thermal runaway behavior and parameter characteristics. Material characterization and thermal analysis tests further explain the overcharge mechanism. The emergence of voltage platform during overcharge is considered to be a significant characteristic for the high-power batteries which can be considered as an important criterion for suppressing thermal runaway. The reason for the appearance of the voltage platform is further discussed and the relevant thermal runaway critical parameters near the voltage platform under different overcharge rate are summarized. Thermal runaway risk assessment of overcharge and the critical parameter analysis of early warning are established to provide references for battery management system.