Low-temperature charging strategy optimization based on electrochemical-aging-thermal coupling model

Lithium plating occurring on anodes of lithium-ion batteries severely restricts fast-charging capability and brings significant degradation when low-temperature charging. Although strict control of lithium plating provides the possibility for undamaged charging, it seriously limits the charging speed. To explore a desirable trade-off between charging time and battery health, this study proposes a model-based low-temperature charging strategy optimization method. Firstly, an electrochemical-aging-thermal coupling model covering lithium plating is established to provide theoretical guidance for the formulation of charging patterns, which considers the reversibility of lithium plating and quantifies the irreversible lithium loss induced by lithium plating. Furthermore, a multi-step constant current charging strategy with segmented optimization based on the battery health state is designed using a genetic algorithm. The charging strategy breaks through the limitation of lithium plating free boundary and effectively shortens the low-temperature charging time. Compared with the constant current charging method at -15 °C, the optimized multi-step constant current charging strategy achieves a 9 cycles extension and a 0.12% reduction in average capacity loss per cycle while shortening average charging time per cycle by 12 min, which provides feasible health-conscious charging.