Battery equalization technology can effectively reduce the inconsistency in the process of using the seriesconnected lithium battery packs. A new equalization topology is proposed using Cuk chopper circuit as the equalizer. The equalization topology uses a twolayer switch to select the single equalization cells to connect to the Cuk equalization converter. At the same time, the Cuk equalization converter adopts zero voltage conduction technology. The equalization scheme uses a singlelayer equalizer to achieve simultaneous transfer of the equalization energy among the single cells in the module and the single cells in different modules. The equalization scheme has the advantages of continuous equalization current, small fluctuation and high equalization energy transfer efficiency. The chargedischarge equalization experiment and static equalization comparison experiment on a battery pack with 12 series lithium batteries were performed. The experiment results show that this scheme can effectively reduce the inconsistency among single cells and improve the overall performance of the battery pack.