A Dual-layer Equalization Circuit based on a Flyback Converter-inductor Battery Pack

Equalization of the battery by inductor, capacitor, and transformer as the three most common active equalization methods, a single equalization circuit structure has different drawbacks each. In order to ameliorate the disadvantage of transferring energy only between adjacent simple cells in the traditional inductive equalization circuit architecture, in this paper, an equalization topology is designed based on the combination of the flyback converter and inductors, with the top and bottom equalizers using the SOC (state of charge) of the battery pack and the SOC of the single cell as the equalization on condition, respectively, so as to achieve the effect of equalization of the energy of the Li-ion battery, which has the advantages of rapid equalization, simple control and ease of expansion. By building a simulation model in Simulink leads to the conclusion that the equalization time of the entire battery module is 154s, and the value of SOC when achieving equalization is 88.41% which is about 80% shorter than the traditional inductive equalizing circuit, and the equalization efficiency is approximately 0.35% higher and the results demonstrate the effiectiveness and superiority of the designed equalization circuit.