One ultrasonic measurement for non-invasive and whole-life-cycle thermal diagnosis of lithium-ion batteries

Thermal characterization and diagnosis are critical for the whole-life-cycle safety of lithium-ion batteries (LIBs). However, conventional techniques are time-delayed and discontinuous due to the sealed structure and intricate mechanisms of LIBs. Herein we report an innovative non-invasive approach for whole-life-cycle thermal monitoring of LIBs. For the first time, our approach combines ultrasonic measurements and heat transfer analysis to diagnose the average temperature and heat capacity accurately, with an error of 2.48%. We furthermore link ultrasonic features to specific failure stages from early incubation to the onset of thermal runaway (TR), paving a new ultrasonic way to interpret the failure modes and give early-warning of TR in LIBs. Using the ultrasonic features, the TR warning can be 32.47 min ahead compared with commonly-used voltage clues. These ultrasound-enabled approaches are attractive to multiple stages in battery life, including the first- and second-life thermal stability evaluation, regular monitoring, failure analysis and end-of-life early warning.