In these days, where the issue of environmental pollution and climate change is stronger than ever, the institutions of government around the world are looking for alternative and more sustainable ways to produce and consume energy. The transports represent one of the biggest impacts of human beings on the planet and for this reason is nowadays at the centre of the global debate. Internal combustion engines had been crucial for the development of the modern economies since the end of the 19th century. However,despite the large improvements of these latter in recent decades, the increasingly stringent restrictions on emissions are forcing vehicle manufacturers to hybrid and electric power-trains.