In situ observation of thermal runaway propagation in lithium-ion battery electrodes triggered by high-frequency induction heating

Lithium-ion batteries (LIBs) are instrumental for electric vehicles, but safety is a concern due to thermal runaway (TR) events. In this study, an in situ observation method for TR and its propagation (TRP) in LIB electrodes is presented, employing high-frequency induction heating as the TR triggering method. The non-contact, rapid heating technique facilitates direct trigger of TRP in a self-made tempered glass observer. Experiments reveal that venting occurs in all samples, and dendritic burn patterns appear on separators upon TRP. The heat-induced shrinkage of separators is more pronounced on the anode side. Phenomena observed during tests include gas flow paths, drifting sparks, short-circuit propagation, and electrolyte boiling. This method may contribute to a better understanding of LIB TRP behavior, facilitating strategies to improve safety and TR characteristics.

Automated summary

In this study, an in situ observation method for thermal runaway (TR) and its propagation (TRP) in lithium-ion battery electrodes was proposed using high-frequency induction heating as the TR triggering mechanism. The non-contact, rapid heating technique enabled direct observation of TRP. It was found that venting occurred in all samples and dendritic burn patterns appeared on separators during TRP. The heat-induced shrinkage of separators was more pronounced on the anode side. Phenomena observed during tests included gas flow paths, drifting sparks, short-circuit propagation, and electrolyte boiling. This method contributes to a better understanding of LIB TRP behavior and facilitates strategies to enhance safety and TR characteristics.