Active equalization of series/parallel Li-ion battery modules including no-load conditions

In Li-ion battery systems, series and series/parallel arrangements of Li-ion modules are quite common to increase voltage levels or energy capacity. This paper proposes an equalization method for Li-ion energy systems using a voltage sharing method, under load and no-load conditions. The proposed system uses module-level DC/DC power converters both for global energy exchange and equalization. The proposed method can be easily extended to an arbitrary number of series/parallel modules and introduce a no-load equalization strategy for only series arrangements.