Contents I. Introduction
NOWADAYS, the transportation sector is mostly dominated by internal combustion vehicles, in which the mobility sector contributes to 29% of total greenhouse emissions [1]. The rapid depletion of fossil fuel reserves and the indisputable reality of global warming, led to a raise of awareness regarding environmental pollution. In this context, more efforts were put towards the electrification of transportation especially in the automotive industry [2]. These efforts were made easier with the emergence of new storage technologies such as Lithium-ion (Li-ion) batteries, which made the traveled distances of Electric Vehicles (EVs) longer and thus more reliable. However, the lifetime of these batteries tends to decrease quickly due to the high-power peaks during sudden accelerations and braking phases. Since the perfect source does not exist, a Hybrid Energy Storage System (HESS) based on Li-ion batteries and Supercapacitors (SCs) could offer a solution to this issue. The SCs could then provide (or absorb) the power peaks while the batteries supply the bulk average power to the load [3]. On the other hand, the power converter is another important element to take into consideration, which should be neither too small, leading to irreparable damages linked to the high power transit between the source and the load or the opposite, nor too big which could add extra volume, and thus reducing storage space and decreasing the performances of the HESS as shown in Fig. 1.
Ragone diagram showing the influence of the converter size on the HESS on a log scale.
