A Novel Optimized Li-ion Battery Charging Protocol for EV Onboard Chargers

An optimal charging profile for Li-ion batteries is proposed in this paper. The objective of the charging process is to minimize the charging time of a Li-ion battery while concurrently minimizing its energy losses. To address this challenge, a multi-objective evolutionary optimization algorithm, SPEA2, is employed. For this purpose, the extraction of electrical parameters for the equivalent circuit model of the Li-ion battery is addressed. Thereafter, the polarization voltages of the Li-ion battery are utilized as a key criterion in the SPEA2 optimization algorithm. Additionally, a power loss analysis of the onboard charger converter is conducted, and simulation results are presented to validate the theoretical analysis. The results demonstrate that the proposed charging method has reduced the charging time by $\mathbf{1 6. 1 7 \%}$ and the power losses of the charger system by 6.08% compared to the Constant Current-Constant Voltage (CC-CV) charging profile.