Temperature-Adaptive Alternating Current Preheating of Lithium-Ion Batteries with Lithium Deposition Prevention

Alternating current (AC) is capable of heating up a lithium-ion battery efficiently before charging at low temperature. Generally, the lower the frequency of the AC current, the higher the heat generation rate. Yet at low frequency, there is a risk of lithium-ion deposition during the half cycle of charging. This study develops a temperature-adaptive, deposition-free AC preheating method. The electrochemical impedance spectroscopies (EIS) of both positive and negative electrodes are measured at different temperatures using a three-electrode lithium-ion cell. The equivalent electric circuit (EEC) models are fitted through the EIS data. The maximum permissible amplitudes of the heating current without incurring lithium deposition at different frequencies are determined at each temperature using the fitted EEC model and the lithium deposition potential. Combining the maximum permissible AC current and the heat generation rate model in the frequency domain, a multistep AC preheating method, in which the amplitude is adjusted according to the cell temperature, is developed. Using this method, the cell can be heated from −20°C to 5°C within 800 s at 100 Hz frequency with the multistep temperature-adaptive amplitude profile.