Modeling, Evaluation, and State Estimation for Batteries

State estimation of the lithium-ion battery has been the focus of many researchers, and the consensus is that the model-based method is an effective tool for state of charge (SoC) estimation. In this chapter, we start with battery modeling. Several modeling approaches are presented and the their advantages and disadvantages are discussed. Moreover, the balance problem between model accuracy and complexity of an nth order RC networks model is tackled using an evaluation index of terminal voltages. Finally, the adaptive extended Kalman filter algorithm is proposed to estimate the SoC and its validity is confirmed.