Lithium-ion (Li-ion) batteries have been increasingly used in electric vehicles (EVs) in the past ten years due to their high energy and power density. However, the poor performance at low temperatures is the main challenge to the deployment of EVs equipped with Li-ion batteries because it has great influence on the driving range. In this study, conductive heating method is proposed to improve the lithium ion battery performance at low temperatures (-20°C ～ -5°C). Both experimental testing and numerical simulation are employed to compare different heating protocols to minimize the temperature gradient, external heating power and heating time. Results show that simultaneous heating with small external power and high discharge voltage can obtain optimal performance as compared to preheating protocol. In addition, internal heating combined with external heating could heat up the battery from -20°C to 0°C in only 1 minute which is an effective strategy.
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