Robust Lyapunov based Observer for Estimation of SoC of Lithium-Ion Battery

State of Charge (SoC) estimation is one of the most important functions of the Battery Management System as it ensures safe and reliable operation of Lithium-Ion battery. A state estimator is used for Open Circuit Voltage (OCV) estimation, which is then used to estimate SoC from the known SoC-OCV function. A robust observer is used for state estimation since the internal parameters of the Lithium-Ion battery are sensitive to SoC. Moreover, the stability and convergence of the proposed observer are guaranteed by Lyapunov-based stability analysis. The simple design and less computational complexity of the proposed observer makes it easy to be implemented on a low-cost microcontroller.