The increase of greenhouse gas emissions and environmental pollution leading to global warming have made it necessary for measures to be taken to increase the production and usage of electric vehicles. Instead of fossil fuels, these vehicles, which are powered by electricity from sustainable sources, promise hope for global warming through zero emissions. Batteries for electric aircraft are in important position. In these vehicles, the primary energy source or primary auxiliary energy source is high-density batteries. Temperature is one of the most important factors impressive battery performance as it shortens battery life. Lithium ion batteries are the preferred battery in this study because they have a high specific energy and energy density. This study examined the performance of the heat generated by 10 prismatic batteries. These batteries were connected to each other in series. The cathode of the batteries is LiMn2O4. A three-dimensional thermal analysis was performed under natural and forced transport conditions. The temperature of the batteries rises in the middle of the battery module and an uneven temperature distribution was observed under natural convection. Because of the heat transfer from each battery's surface, both a decrease in temperature was observed and a balanced temperature distribution happened under forced convections. As the C ratio decreased, the temperature of the batteries decreased, but this process requires a longer time. For this reason, C values should be selected according to the battery capacity and working environment. (C) 2020 Elsevier Ltd. All rights reserved.