A flexible optimization study on air-cooled battery thermal management system by considering of system volume and cooling performance

When the battery temperature exceeds the normal range, the battery efficiency performance, and life will be significantly reduced, and the battery may even explode. Therefore, an optimal battery thermal management system is required to dissipate heat efficiently. The existing research focuses on the structural design to reduce the maximum temperature of the system. However, the volume of the cooling system is also important for electric vehicle design, which has received little attention. In this study, a new flexible optimization strategy for a battery thermal management system is proposed, which is a hybrid of system volume and cooling performance and can determine the appropriate optimized structure according to the engineering applications. The proposed method belongs to four steps: optimization system design, establishment of shortcut computation codes, multiobjective optimization and comprehensive fuzzy decision making. The numerical simulation based on computational fluid dynamics (CFD) is used to verify the cooling performance of the optimized system. Compared with the three existing designs of battery thermal management system from previous literatures, the volume is reduced by a maximum of 13.01 %. In the process of stable heat generation, the maximum temperature difference decreased by 65.79 %, 40.65 %, and 63.69 %, and the temperature uniformity increased by 65.87 %, 34.93 %, and 60.80 %, respectively. In the unsteady heat generation of the battery pack, at the discharge rate of 5C, the maximum temperature difference decreases by 2.28 K, and the maximum temperature difference and temperature uniformity decrease by 57.11 % and 49.15 %, respectively.