In recent years, electrification of transportation sector has become more relevant due to the growing necessity to reduce pollutants emitted by conventional engines, fed with carbon fossil fuels. One of the most important components of an electric powertrain is the energy storage system, usually a Lithium Ion battery, responsible of energy storage and generation of electric current to make the motor work. Among different factors affecting battery characteristics, such as performances, life time and safety, temperature is the one of biggest impact; thus its influence during normal working conditions must be monitored and studied. This thesis introduces a thermal lumped parameter model of a battery, implemented in MathWorks Matlab R2021a environment, able to estimate its temperature while undergoing some reference test cycles.