A multistage current charging method for Li-ion battery bank considering balance of internal consumption and charging speed

Abstract

A useful fast charging method should make a balance between battery's safety/cycle life and charging time. So, the internal temperature or energy loss of battery should be controlled in charging process. This paper proposes a charging method for Li-ion battery bank to balance both energy loss and charging time. Firstly, the method gives a procedure to get the function of the internal direct current (DC) resistances varying with state of charge (SOC) and charging currents. Then the energy loss function is simplified and an objective equation is proposed for balancing charging time and energy loss. Finally, for real time implementation, a multistage current charging curve is designed with different weight factors in each stage. Experiment shows the advantages of the method.