The invention describes a charge equalizer which connects a strong with a weak cell directly via a multiplexed DC-bus and a DC/DC-converter. Due to the direct connection the energy dissipation is much lower compared to systems where the energy is only transferred from one neighbour to the next. The direct connection only requires low voltage components which simplifies the circuit design reduces its costs and increases the efficiency. By additional implementation of an energy buffer the technical complexity of switching cells with differing voltage levels can be reduced and hence the design of the multiplexed DC bus can be simplified.
The intelligent control reduces the power dissipation compared to existing solutions as it allows the direct support of weak cells and it reduces the production costs as expensive high-voltage components can be replaced by low voltage components.