3D CFD Modelling of Thermal Management System of Liquid Cooled Lithium-Ion Battery for EV

Transition from conventional engines to electrification in light duty and heavy-duty vehicles has become crucial due to inevitable necessity to diminish CO2 emissions to achieve more sustainable transportation. One of the significant issues of electrified powertrain is energy storage, mainly Lithium-Ion Batteries, and its thermal and mechanical maintenance. Battery Thermal Management Systems have been developed in various ways to ensure that the batteries are kept in safe temperature ranges to prevent any hazardous situations, and to prolong their useful life. Therefore, in this thesis work a 3D CFD model was created by using Simcenter Star-CCM+ to simulate the battery cooling system, which is indirect liquid cooling, of a light duty electric vehicle. Firstly, pressure drop analyses of the cold plate were done for different inlet mass flow rates and temperature values to characterize the design. Then, starting from the battery module level, steady-state and transient Conjugate Heat Transfer simulations were done for mesh sensitivity and physics sensitivity analyses. Heat generation rates of battery cells were taken from 1D CFD GT-Suite model, while heat generation values of busbars and tabs were calculated using Joule effect for simulated C rates. Furthermore, the battery module level model was validated with experiment data of 2 C charge condition. Lastly, by using the battery module model, entire battery pack model was obtained. Applying the same approach of battery module level model, the battery pack model was validated with experiment data of 1 C charge condition. The comparisons between the CFD models and experiments showed that the created methodology is able to capture the temperature values and transient trends well with extremely small deviations, opening up to the possibility of using this methodology for the development in a very early stage.