An Automotive Onboard Self-Heating Method Based on Reconfigurable Battery System in Cold Climates

Lithium-ion batteries in cold climates suffer from significant performance degradation, such as reduced available power and life cycle deterioration. To address this problem, a reconfigurable battery system (RBS) based self-heating method is proposed in this article. This innovative approach leverages a switch array integrated within the RBS, achieving self-heating with a fast temperature rise and low energy loss. Additionally, employing ac heating current with high frequency further mitigates damage to the battery. The modularized three-switch reconfigurable topology is proposed, and the ac-heating principle is designed. Also, based on the frequency-dependent characteristics of the battery impedance, the heating strategy is developed to accurately control the heating current. The experimental results demonstrate the efficient heating capability: the battery can be heated from −30 °C to 0 °C within 237 s by consuming only 6.27% of nominal capacity, and the battery capacity fade rate is only 0.47% after 200 heating cycles.