Modeling and Thermodynamic Analysis of Li-Ion Battery for EV Using MATLAB

LI-ion battery cells used in EVs are subjected to different charge and discharge rates due to the varying and fluctuating demand for power by the user. The different C rates in turn will have variation in internal heat profiles. This paper will provide a prediction of the total heat generated in cells from joule heat and reaction heat. The project has an experimental method to measure joule heat by performing HPPC tests at different C rates and at different cell surface temperatures. To measure reaction heat an experimental method is designed to test cells at different temperatures. Calculation of entropic heat coefficient to be done from open circuit voltage vs temperature graph. MATLAB Simulink model used to predict the temperature at a specific time by providing C rates. Simulation of the thermodynamic behavior of the cell is done on calculated heat generation values. Reaction Heat part cannot be ignored in calculation of total heat generation by cell. It plays a major part in low temperature environment and lower C rates.