Study on the cell change cycle for cell voltage equalization circuit using an LC series circuit

Series connections of the cells of energy-storage devices such as electric double-layer capacitor (EDLC) and lithium-ion battery result in voltage imbalance in each cell because of the nonuniform properties of the individual cells. In previous work, the authors proposed a novel cell voltage equalization circuit using an LC series circuit. In the proposed circuit, the differences of the convergence time and the efficiency had occurred according to the value of the cell change cycle T_cc- Therefore, the characteristics when T_cc was changed were verified by the simulation and the experiment in this paper. The simulation results and the experimental results showed that shorter convergence time with high efficiency can be obtained by setting T_cc to T_rs/4, where T_rs is resonance period of LC series circuit used in the proposed circuit.