An any-cell-to-any-cell equalization based on half-bridge CLLC converters for Lithium-ion battery strings

In this paper, a charge equalization converter using a multi-winding transformer is proposed. The proposed scheme achieves the cell-to-cell charge transportation by LC resonant tank and half-bridge CLLC converter. In this operation, adjacent two cells share a LC resonant tank and a half-bridge CLLC converter. Therefore, the number of windings cuts in half in comparison to conventional multi-winding charge equalization converter, resulting small circuit size. To verify the operation of the proposed charge equalization converter, simulation for six lithium-ion batteries stack is given.