Battery Current Estimation Based on Simple Model with Parameter Update Strategy Using Piecewise Linear SOC-OCV

A current sensorless technique in battery management system (BMS) serves to reduce overall power losses in the system as well as the cost needed to produce a mass BMS. In this work, current estimation algorithm is constructed based on the dynamics of simple battery model by utilizing internal capacitance update using a set of linear piecewise functions of State of Charge and Open Circuit Voltage (OCV-SOC). To verify the effectiveness of the constructed current estimation algorithm, pulse-load experiment and varying-load experiment are conducted on a lithium-polymer battery. From each experiment, current estimation is compared to the measured current obtained from sensor readings. The results show that the current estimation manages to track the current-sensor readings from pulse-load experiment and varying-load experiment.