Improvement of EVs range by hybrid storage units

Nowadays, electric vehicles (EVs) are of great interest over the world. In the past, the diffusion of EVs was impeded because of the limits of energy storage units, which reflect in vehicle range limited extension. In recent years, a significant progress was made in terms of power and energy density thanks to the lithium based batteries that can guarantee vehicle ranges higher than 100 km. Another further step can be done by coupling more than one storage technology and leading to an increased efficiency and extension of the vehicle range. In this paper, the effectiveness of adding another storage unit to a lithium ion battery is investigated for different EVs and driving cycles. Furthermore, a methodology procedure, based on the knowledge of the test driving cycle, and parameters of the EV, is proposed to find the optimal size of the auxiliary storage, that maximizes the EV range.