Acoustic Emission–force Coupling Behavior during Drop-weight Impact of Lithium-ion Batteries

키워드

확장요약문

Acoustic emission (AE) monitoring is a promising non-destructive approach for detecting internal, sub-critical damage in lithium-ion batteries under mechanical impact, but which physical loading variables an AE signal actually tracks remains poorly established. This study investigates the coupling between AE activity and the mechanical force response of lithium-ion cells during instrumented drop-weight impact testing. Cells were impacted at multiple energy levels, and AE signals were recorded simultaneously with the drop-weight tower's force, displacement and energy channels. An active AE window was identified from the signal envelope, and AE features were examined jointly with the impact energy and the time-varying force response, including its rate of change. The results indicate that AE activity tends to intensify with impact severity, and that the AE envelope shows a degree of temporal coupling with the force dynamics that becomes more pronounced as impact energy increases. This suggests that AE reflects the ongoing dynamics of energy release during loading, rather than only the final deformation left in the cell, providing a physically grounded basis for using acoustic emission as a non-destructive indicator of impact severity in lithium-ion batteries.