Developing an active balancing model and its Battery Management System platform for lithium ion batteries

Batteries in Electric Vehicles (EV) and Hybrid Electric Vehicles (HEV) are the most sensitive and delicate part in a car due to their high risk of bursting, ignition or explosion. The system has to ensure safety conditions for the user and its surroundings. Due to that, hundreds of studies had been done in order to provide a good operation of the Battery Management System (BMS). BMS tasks include measure cell voltage, sample current battery, measure cell temperatures, perform cell balancing, and calculate State Of Charge (SOC). All efforts are concentrated in improving its performance and maximizing the energy that can be given by the battery. To do that BMS are redesigned every day in order not to lose power and try to make a good distribution of the batteries. A way of making the battery to live longer is equalizing the energy of its cells. This paper shows a model in MATLAB R2010b of active balancing to re-distribute the energy among batteries and make them to age at the same time; this allows the battery to live longer and avoids wasting energy. Due to that a BMS support is essential. This paper also presents a custom BMS platform and its main parts to achieve the necessary information from the battery to perform a good active balancing.