Experimental Study on DC Pulse Discharge Preheating of Lithium Ion Batteries at low temperature over a wide frequency range

The severe degradation of Lithium-ion batteries (LIBs) performance at low temperatures needs to be recovered by preheating, while pulsed preheating is often considered as a good internal preheating method. In this paper, a heating experimental platform for Li-ion power batteries under pulse excitation is built, and the electrochemical impedance spectrum (EIS) and the convective heat transfer coefficient h of experimental 18650 Li-ion batteries are tested to carry out pulse excitation temperature rise experiments in the frequency range of 1Hz~80kHz. The experiments show that the temperature rise rate of lithium-ion battery decreases with increasing frequency in the range of 1Hz-6kHz, and becomes faster with increasing frequency in the range of 6kHz-80kHz, which verifies the validity of the temperature rise model of lithium-ion battery.