A comprehensive investigation of thermal runaway critical temperature and energy for lithium iron phosphate batteries

The thermal runaway (TR) of lithium iron phosphate batteries (LFP) has become a key scientific issue for the development of the electrochemical energy storage (EES) industry. This work comprehensively investigated the critical conditions for TR of the 40 Ah LFP battery from temperature and energy perspectives through experiments. The kinetic parameters were obtained and the TR characteristics under an adiabatic environment were elucidated by adiabatic TR experiments, and the TR critical temperature and energy were obtained by experiments under different heating powers. The results indicate that the critical TR temperature Tcr of LFP batteries exhibits a logarithmic relationship with the heat transfer coefficient h. The heating power is inversely proportional to the time taken to trigger TR in the heated cell. Furthermore, under the open environment, the dichotomous idea was used to obtain the critical temperature at which thermal runaway occurs as 125 ± 3 °C, and the critical energy Ecr required to trigger thermal runaway is 122.76 ± 7.44 kJ. This work can provide a theoretical basis and some important guidance for the study of lithium iron phosphate battery's thermal runaway propagation as well as the fire safety design of energy storage power stations.