Revealing the failure mechanisms of lithium-ion batteries during dynamic overcharge

Overcharge is a critical safety issue for the large-scale application of lithium-ion batteries. In-depth understanding the dynamic overcharge failure mechanism of lithium-ion batteries is of great significance for guiding battery safety design and management. This work innovatively adopts the fragmented analysis method to conduct a comprehensive investigation of the dynamic overcharge failure mechanism. By connecting the failure mechanism under different characteristic voltages in series, the dynamic failure evolution mechanism during the entire overcharge thermal runaway process is deduced. For each characteristic voltage, the thermal stability of different cell components in multi-scales and mechanical properties of cell components are revealed. Multiple characterization methods are utilized to resolve the occurrence and severity of side reactions from morphology, composition, and structure of the cell components. Furthermore, the thermal stability and mechanical properties evolution of cell components, and the dynamic failure evolution mechanism are systematically revealed during the entire overcharge thermal runaway process. The findings by this study can facilitate the optimal design of cell components and provide certain guidance for the optimization of battery safety management systems.