Rapid preheating method for lithium-ion battery pack based on shared topology circuit solution with energy consumption analysis

The performance of lithium-ion batteries for electric vehicle degrades heavily under low temperature environments. To solve this problem, this paper proposes a rapid preheating scheme for on-board battery packs based on the shared topology circuits with the motor control system and frequency and amplitude varying strategy under low temperature environment. Firstly, the impedance characteristics of the battery at low temperature are analysed based on EIS experiment, and the parameters of the battery equivalent circuit model were fitted through least square method. An electrothermal coupled battery self-heating control model is then established to precisely characterize the battery electrical and thermal behaviour characteristics. Secondly, based on the particle swarm algorithm, a variable frequency amplitude sinusoidal AC heating strategy is proposed with the goal of increasing the battery heat generation rate. By building a battery self-heating experimental platform, the accuracy of the model's electrothermal performance description is verified. Finally, the effectiveness of the proposed heating scheme is verified through model simulation analysis, and the energy consumption of the heating process is discussed. The results show that this scheme can greatly improve the temperature rise rate of the battery pack from −30 °C to 0 °C. As the battery SOC is 50 % and 80 %, the average temperature rise rate can reach 3.5 °C/min and 10.9 °C/min respectively. The energy consumption rates for the entire process are 0.23 %/°C and 0.20 %/°C of the nominal capacity, respectively.