Abstract— The most important factor limiting the efficiency of Lithium-ion (Li-ion) batteries is their thermal performance. Therefore, the analysis of battery thermal management (BTM) of this type of batteries is of a great interest. This work aims at evaluating the effectiveness of different types of passive and active BTM systems. The electro-thermal behavior of the battery pack is characterized using 3D finite element method (FEM) modeling. The heat generation rate of battery cells during utilization is determined, so that the thermal behavior of the battery pack can be evaluated. The different BTM solutions are evaluated to determine the improvements in the pack thermal behavior. For further improvements, a new mixture of phase-change materials (PCM) is proposed and simulated. The mixture contains 75% of hydrogel and 25% of paraffin wax (PW). The results show that the mixture enables reducing the weight of the BTM material while slightly reducing performance. The end result is reducing the operating cost of the system especially for aerospace applications due to the reduced weight, which is the most important factor. In addition, cooling can be enhanced by the wind.