Extended Kalman Filter based SOC estimation of Lithium-Ion Battery

Battery Management System (BMS) is an electronic unit used for safety, durability and maintaining the performance of a rechargeable battery. It has become an integral part of modern batteries. Key functions of the BMS are Battery monitoring, Battery control and communication. Battery monitoring unit monitors the cell temperature, voltage and current. Battery control takes care of cell balancing, calculation of state of charge (SOC) and state of health (SOH) and control unit communicates the gathered information. In this work the focus is on estimation of state of charge using extended Kalman filter. SOC is estimated for a given drive cycle at different temperatures and compared it with the SOC estimated using the coulomb counting method. To calculate the actual SOC, SOC-OCV relationship for the given battery is made use.