Research on Optimization of Charging Strategy Control for Aged Batteries

Rapid charging of lithium-ion batteries has become a major bottleneck for the large-scale deployment of electric vehicles. In this article, a charging optimization method is proposed for lithium ion batteries based on their aging characteristic, which takes charging time and temperature rise into consideration. An electric-thermal battery model is utilized to estimate the battery temperature during charging. A search for the optimal charging current pattern is performed using a particle swarm optimization (PSO) algorithm combined with fuzzy reasoning. The experiments are conducted on batteries with different aging states to verify the proposed method. Besides, the proposed method is compared with traditional constant current-constant voltage (CC-CV) charging method. Results show that the proposed charging strategy has advantages on maximum temperature rise maintenance and charging speed improvement for aged batteries with unknown aging state. The proposed charging method provides a way for aged batteries charging considering charging time and temperature rise.