Numerical investigation on the thermal management of Li-ion batteries for electric vehicles considering the cooling media with phase change for the auxiliary use

Abstract

This study investigates the thermal management of a battery module of an electric vehicle for the recovery of waste heat. In the evaluation of this waste heat, a two-phase flow system is used to provide a more effective heat transfer. The battery system was formed of 6 serial connected prismatic Lithium-Ion cells. It was aimed to design a 134.55 kW electric vehicle battery system. For this aim, 360 battery modules were used. The maximum amount of waste heat obtained from these modules was recorded as 6.192 kW. Since it is aimed to use this waste heat in the auxiliary cycles such as air conditioning and extra electricity production, R600a was used as the cooling media. A parametric study was conducted for different discharging rates (C) and depths of discharging (DoD) through computational fluid dynamics (CFD) for performing the thermal analysis of the battery module. The heat transfer coefficient was determined ranging between 1.10 and 5.49 kWm � 2 K-1. The cooled module temperature was recorded between 290.93 K and 317.31 K, whereas it was recorded as 332.57 K for the non-cooled system. For secondary purposes, the refrigerant mass rate ranging between 0.2760 kgs � 1 and 0.6559 kgs � 1 was obtained in a temperature range of 283 K and 313 K.