Before a CubeSat starts to operate in orbit, several tests are performed to ensure its subsystems work according to design specifications. In this sense, numerical simulations are a fundamental tool for testing representative operating scenarios, which are often difficult to reproduce in the laboratory, especially because of the microgravity environment, vacuum, temperature, and radiation levels found in space. In a satellite project, including CubeSats, some questions to be answered before the satellite is even manufactured include its temperature in orbit, especially the battery, which is one of the most temperature sensitive components and usually requires thermal control to prevent failures. Operating the battery in temperature ranges outside those recommended by the manufacturer can increase its degradation or even cause permanent failure, which puts the entire mission at risk. The temperature scenario in which a CubeSat is exposed depends directly on its orbit and attitude, which also impacts the temperature field of the battery. However, internal heat generation occurs naturally during battery operation and must be considered in thermal modeling. This phenomenon depends, among other factors, on the current drawn and the time it is being used. This work seeks to thermally model in CFD (Computational Fluid Dynamics) the thermal behavior of a battery integrated into a CubeSat to obtain the battery’s temperature scenarios. To achieve this, the thermoelectrical modeling of the battery and the thermal modeling of the CubeSat are created and solved in the Ansys CFX software. Different orbits and currents are considered in the analyses to present possible temperature scenarios for the battery, which can assist in the planning and development of the Electrical Power System (EPS) and Thermal Control subsystem of a CubeSat mission. The results indicate scenarios in which attention should be paid to the thermal management of the battery to avoid temperatures that are too low, and this could be used to design the thermal control subsystem.