According to present evolution trends for ICE vehicles, different architectures of the vehicle electric powernet and improved energy storage systems are required. In particular, the use of a 36 V as nominal voltage for the powernet, in addition to the conventional 12 V one, will be needed to face the increasing power demand caused by fuel consumption reduction needs, comfort and safety concerns. This will require developments in the field of batteries. In this paper, the trends of development of the electric powernets on conventional vehicles are described along with future system architectures and battery requirements. This last topic includes technical aspects related to the sizing, performance, operating voltage range, technologies proposed, management system and safety concerns.