An Impedance Based Modeling Towards the Aging Prediction of Lithium-Ion Battery for EV Applications

Modeling of Lithium-Ion Battery (LIB) is essential for studying its behavior under different operating conditions like temperature, load current and state of charge. The parameters of a LIB such as capacity, open circuit voltage, impedance can be characterized by using a suitable model according to the application. This paper has proposed an impedance-based equivalent circuit modeling (ECM) approach for electric vehicles (EV) to estimate the aging of a LIB (LiFePO
₄
) and to prevent the system, where the battery is installed, from failure. The aging has been performed experimentally using a real electric motorcycle load profile and the impedance test results for the aged LIB at different cycles have been fitted and analyzed with a chosen ECM. In addition, the same ECM has been used to analyze and compare the aging for the same battery type with a profile achieved using a hybrid energy storage system (HESS) consisting of LIB and supercapacitors. The ECM for HESS profile showed smaller impedance change and smaller capacity reduction with aging compared with the ECM for the battery profile. Therefore, it validates that HESS has a longer cycle life than battery energy storage system.