A hybrid physical modeling and AUKF approach for optimizing low-temperature charging of lithium-ion batteries

A common method for charging lithium-ion batteries at low temperatures involves preheating to mitigate low charging efficiency and safety risks from lithium dendrite growth. However, preheating alone is insufficient for rapid and safe charging. Optimization of low temperature charging requires consideration of the coupling relationship between heating and charging processes, while avoid lithium plating. Therefore, this study first constructs an electrochemical-thermal coupled model suitable for a broad temperature range to access the internal states of battery during low-temperature charging, ensuring lithium plating-free. Then, a hybrid physical modeling and AUKF method is proposed to accurately capture the changing state of charge (SOC) and state of temperature (SOT) during low-temperature charging, which is essential to improve the simulation accuracy of the model. After that, this study proposes a multi-stage heating-charging strategy which is controlled by hybrid physical modeling and AUKF approach to consider charging efficiency and safety. Optimization algorithm is used to obtain the optimal sequence of decisions for charging and heating under different phases to achieve the highest charging efficiency. Compared to One-stage heating-charging strategy, the proposed method offers superior charging efficiency, providing certain convenience for the operation of lithium-ion batteries in low temperature environment.