A Battery Management System using an active charge equalization technique based on a DC/DC converter topology

A novel active charge equalization technique based on a DC/DC converter topology is proposed in this paper. The technique achieves cell balancing of batteries in a stack in terms of both voltage and charge as the pack is being charged/discharged and in idle periods to maximize the energy and reliability of stack operation. A set of MOSFET switches controlled by a voltage monitoring circuit ensures that each battery module has the same output voltage by transferring charge from an individual battery module with the highest voltage to a weak module. An overvoltage and over-discharge protection circuit is presented to reduce the degradation of battery life and to operate each battery within the voltage limits.