TEMPERATURE ANALYSIS OF ELECTRIC VEHICLE LITHIUM ION CELL

Abstract

A lot of research has been done for constant discharge process of lithium-ion batteries, but study on thermal behavior of lithium-ion batteries during operation under realistic cycles is scarce. So, the main aim of this study was to better understand the temperature variation of a lithium-ion battery cell when it is charging/discharging. For this study, the thermal responses of a lithium ion cell will be carried out in ANSYS and compared. To accomplish this, each cell was be subjected to several discharge and charging processes. The result obtained was in form of temperature contours and plots evaluating which the thermal response of the cell was compared. In ANSYS, first a cell was simulated with a series of simple discharges at various C-rates. Next, a combined cycle with few alternating charge/discharge processes will be prepared, and the changes in the temperature, total heat and voltage will be observed. The simulations were done for various constant discharge rates. An evaluation of the result from discharge according to discharge rates ranging of 0.3 C, 1C and 3 C for environmental temperature of 300K was done. Then the cells and module were simulated by employing different cooling fluids. The change in maximum temperature was observed and the appropriate coolant was selected. A sample test to observe the temperature increase in cell during discharging was performed for 0.3 C and its results were noted. For simple discharge, 3M Novec 7100 is found to be a better cooling fluid. While for charge discharge cycles, water was found to be better coolant.