A Battery Cell Equalisation System Based on a Supercapacitors Tank and DC–DC Converters for Automotive Applications

Abstract

A battery cell equalisation system for automotive applications based on a supercapacitors energy storage SCES tank is proposed. The main advantages of the developed system are the utilisation of the regenerative brake energy for battery cell equalisation, reduction in the number of DC–DC converters, the flexible operation expressed by the possibility to address each battery cell with bi-directional switches, and acceptable efficiency in all modes of operation. The energy transfer between the SCES and battery cells is precisely analysed with modelling and simulations in steady-state and transient conditions. Power loss is estimated per sub-system, systemising the loss reduction techniques and achieving the maximum efficiency. The required DC–DC converters are described and designed according to the specific modes of operation in the developed application. Finally, the experimental verification is provided using a small physical model.