For the mitigation of global warming, climate protection goals have been formulated including a continuous reduction of CO2 emissions. Therefore, traction technologies based on New Energy Carriers, like Battery Electric Vehicles, are increasingly used in the automotive industry. Lithium-Ion-Batteries are the main technology for traction batteries of electric vehicles, due to their high energy density and very good cyclability. After an event of battery damage, such batteries can undergo a self-heating process, called thermal runaway, leading to high releases of heat and toxic gases and a special burning behaviour that may bring up special safety risks. From a fire safety point of view, this burning behaviour has to be investigated since safety issues can impede the development and popularity of electric vehicles. In addition to the concentrations of toxic smoke gases, the Heat Release Rate (HRR) is the most important parameter for fire safety investigations. A method to determine the HRR accurately is needed and, therefore, investigated in this paper.