Robust observer for state-of-charge estimation of li-ion battery with uncertainties

We developed a robust state-of-charge (SOC) estimation algorithm which considers uncertainties of matrix including internal resistance for Li-Ion battery. We used a linear matrix inequality (LMI) to acquire gain of the observer for estimating SOC. The algorithm is less accurate than estimation results of other algorithms, but has simple and fast calculation by using a time-invariant observer gain. This algorithm can contribute to acquire SOC of old battery cells which have the higher internal resistance and uncertainty of the initial battery model.