Thermo-Mechanical Modeling of a Representative Battery Pack for Electric Vehicles

Thermal management is vital for the performance, reliability, and safety of electrical vehicle (EV) batteries. A proper selection of battery pack assembly materials not only enables the battery to operate in an optimal temperature window, but also helps minimize the stresses in its constituent components, and hence prolongs its life. In this paper, the thermo-mechanical modeling of a representative battery pack, comprising multiple pouch cells, will be presented. Particular attention is given to the gap filler, a thermally conductive composite used to remove heat from the battery cells through a cooling plate. The impact of the thermal and mechanical properties of the gap filler, as well as its interfacial properties and geometric dimensions, on the temperature and stress fields of the battery pack will be studied. The temperature variation of the coolant flowing through the cooling plate will also be considered. In addition, the modeling aspects of the thin gap filler layer to obtain accurate stress predictions will be discussed. This work demonstrates that the utilization of modeling can enable EV battery pack design engineers to select the right materials, and material scientists to develop customized materials for specific applications more rapidly. Ultimately this will reduce new product development cycle time and cost. The insights gained from this study should be of interest to EV battery pack design and modeling engineers, as well as material scientists.