Parameter Estimation of Equivalent Circuit Model for Lithium Batteries

Abstract

AbstractThe internal parameters of the lithium battery would be changed due to the environment and load conditions. Based on the equivalent circuit model, a method is proposed to estimate the equivalent circuit parameters of Li-ion batteries using pulse charge/discharge test data, considering the influence of charge state on the battery component parameters. Presents an estimation procedure of equivalent electric circuit parameters of a lithium-ion cell using data from a pulse charge/discharge test. The model parameters are extracted based on the transient voltage response of the current pulse relaxation process, and the accuracy of the battery model is verified by using the Hybrid Pulse Power Characteristic (HPPC) experimental data. The results show that the maximum error between the simulation results and the experimental results does not exceed 50 mV at the different State of Charge (SOC). The model can easily and accurately simulate the actual characteristics of the batteries, and there is no restriction in number of parallel resistance and capacitance (RC) branches in the electrical model.KeywordsLithium batteriesA second order Thevenin modelParameter estimation