Modeling and evaluation of lithium-ion battery models for electric vehicles application by experimental approach

To improve the applicability of battery model, a new electrochemical-polarization (EP) model was proposed. Based on the evaluations and analysis on the commonly used kinds of lithium-ion battery models, a new EP model was put forward by adding an extra RC network on the basis of the electrochemical model to describe the relaxation effect of the lithium-ion battery, and the open circuit voltage (OCV) as a function of state of charge (SoC) defined by the Nernst model was used in the model to avoid a time-consuming, laborious and even error-prone experiment for specially determining OCV at several specified SoC values. Experiments and simulation results show the new EP model can simulate the dynamics of battery well, and the maximum terminal voltage less than 1%. By using the proposed method and identification approach, the time-consuming and complex experiments for model parameters' identification and periodical calibration are avoided.