Thermal modeling of lithium ion batteries for temperature rise predictions in hybrid vehicle application

Abstract

In order to develop a hybrid vehicle with lithium ion battery packs, it is necessary to understand the thermal behaviour of the lithium ion batteries used. This paper focuses on predicting the temperature rise of lithium ion batteries during a drive cycle in hybrid two wheeler applications. To predict the rise in temperature, a model is developed in Simulink, parameterized using the empirical parameters. The model is based on the Joule heating effect and heat capacity equation while considering the variation of internal resistance with respect to ambient temperature of operation, state of charge and C rate of operation. The internal resistance is measured by parameter evaluation testing through the pulse power characterisation method. To validate the Simulink model, the lithium ion batteries are tested on standard drive cycles and constant current discharges, and the rise in temperature is measured. The accuracy of the Simulink model was found to be ± 2.2°C, which is acceptable for this study and comparable to the other available models in the literature.