Acoustic assessment of lithium-ion batteries: Unravelling temperature and charge contributions

Lithium-ion batteries (LIBs) are critical for renewable energy storage, and accurate charge and health estimation remains a significant challenge. Acoustic sensing offers a unique method to observe lithium-ion movement between electrodes during battery operation. However, both the charge state and the internal temperature of the battery affect the acoustic response. This study systematically investigates the interactions between temperature and charge state on acoustic signals through a novel thermal cycle methodology. Using a global sensitivity analysis, we demonstrate that temperature has a non-negligible and dominant effect on the acoustic signal, with a largely insignificant cooperative interaction with charge state. The results reveal temperature-induced variations in the acoustic signal that increase with charge level, though not uniformly. Our findings underscore the critical importance of temperature compensation in acoustic-based LIB estimation techniques. By quantifying the independent and cooperative effects of temperature and charge, this research provides the possibility of independently measuring thermal and SOC effects on the acoustic signal without the need for additional thermal sensing equipment.