The bachelor's thesis deals with the current legislation in the field of determining the causes of fires in the Slovak Republic. Also with the development of selected technologies of cars and engines that were or are part of the cars. It also deals with the investigation of the causes of fires in personal vehicle and electric vehicle. Furthermore, the bachelor thesis deals with the statistics of a car fire with the focus on the most common causes of fire. The most common causes include intentional ignition, electrical short circuit and operational-technical failures, which are described in my thesis. Subsequently, the thesis describes possible ways of extinguishing cars with electric drive. The different voltage levels in electric vehicles are identified and distributed based on the color of the cabling and the voltage value. Furthermore, the thesis describes what kinds of harmful substances can be formed in the event of a fire in an electric vehicle with a Li-Ion battery.