A Low Cost, Small Ripple, and Fast Balancing Circuit for Lithium-Ion Battery Strings

This paper proposes a low cost, small ripple, and fast balancing circuit for Lithium-Ion battery strings. The proposed topology uses isolated Cuk converter to transfer energy directly from high voltage cells to low voltage cells to achieve high balancing speed. The current and voltage at both input and output of the Cuk converter have small ripple. The cell selecting switches are developed by using relay circuit to implement a low cost balancing circuit. The experimental circuit is implemented for 12 Lithium-Ion batteries in a string to verify the performance of the proposed topology.