In the last few years the issue concerning the pollution and the protection of the environment has predominantly entered into the daily lives of us all, and it is becoming the guiding compass for new investments. In the automotive field is happening one of the biggest change of its history, it is switching from the use of fossil fuels as unique source of energy for the vehicles, to the adoption of electrical energy as primary supply, in other words to replace the traditional combustion engine with the electric motor. An important phase of this turning point is the definition of an energy storage system that meets market demand from the point of view of the autonomy and safety requirements.