Higher order equivalent circuit model analysis of lithium ion battery for electric vehicle

Abstract

To understand behavior of lithium-ion battery in electric vehicle is very crucial for their safe and efficient operation. In this work, higher order ECM model with three RC branches has been investigated for modeling and simulation of INR 18650-20R lithium ion battery. Experimental data of incremental OCV test were used for parametrization of the model at 0 °C, 25 °C and 45 °C, respectively. Trust-region reflective least squares algorithm was used to identify model parameters that were stored as flexible look-up tables. For validation, the simulated voltage profiles of the ECM model were compared with experimental voltage profiles of FUDS profile, DST profile, BJDST profile and US06 profiles at 0 °C, 25 °C and 45 °C, respectively. The results confirm that the model can simulate the voltage profile at different temperature with accuracy of within 3%. The results so obtained discloses the great importance of 3-RC branch equivalent circuit model in practical implementation to various battery management systems for electric vehicles applications.