On-line charging and discharging control of lithium ion battery

In order to use lithium battery as energy storage device in DC operating power supply system, and optimize the performances of lithium ion battery such as efficiency, etc., an on-line charging and discharging control scheme for lithium ion battery in DC operating power supply is proposed. Firstly, the internal equivalent state of lithium ion battery is estimated by the output voltage and current of lithium ion battery. Secondly, the expected charging and discharging state and current value of lithium ion battery is determined by the internal equivalent state of lithium ion battery. Finally, the output voltage of AC/DC converter is adjusted according to the internal equivalent state of lithium ion battery and the expected charging and discharging state and current value. The actual charging and discharging current of lithium ion battery is forced to tend to the expected current value, so as to optimize the performances of lithium ion battery. Theoretical analysis and case study show that the scheme is feasible.