Thermal runaway warning of lithium‐ion batteries based on photoacoustic spectroscopy gas sensing technology

Thermal runaway is the most dangerous failure faced by lithium-ion batteries (LIBs). In this paper, ethylene (C2H4), methane (CH4), and carbon monoxide (CO) were selected as the characteristic gases, the cantilever-enhanced photoacoustic spectrometer was adopted as the gas detector, and a thermal runaway early warning system for LIBs was built based on characteristic gas sensing technology. After a series of repeated experimental calibrations and tests, the effectiveness of the thermal runaway warning system for lithium nickel cobalt manganese oxide (NCM) LIBs was verified. The experimental results show that the average warning times of the thermal runaway warning system were 7.3 and 11.5 min, respectively, for NCM LIBs with a state of charge of 50% and 100%. The warning times of the established system can meet both the requirements of the Chinese national standard GB 38031-2020 and the United Nations global technical regulation ECE/TRANS/180/Add.20. Thus, the thermal runaway early warning system proposed in this paper can gain more time for the fire management of the NCM LIB system and the safe evacuation of personnel.