Energy Storage System Design docx.

ENERGY STORAGE SYSTEM DESIGN
Introduction
As the global economy begins to strain under the pressure of rising petroleum prices and
environmental concerns, research have spurred into the development of various types of clean
energy transportation systems such as Hybrid Electric Vehicles (HEVs), Battery Electric
Vehicles (BEVs) and Plug-In Hybrid Electric Vehicles (PHEVs) [1–5]. Especially PHEVs
acquire the most attention due to the combination of electrical source and conventional engine.
This type of vehicle provides the user a considerable pure electrical range and also an extended
range, which can be performed by a conventional Internal Combustion Engine (ICE). The
establishment of a Rechargeable Energy Storage System (RESS) that can support the output
power during acceleration, efficiently use the regenerative energy and perform for a considerable
cycle life are the critical aspects to be met by battery technologies [6–8].
During the last decade, a series of hybridization topologies have been proposed in order to
enhance the power density and cycle life performances of energy storage systems [9–12]. In [13–
19] is documented that the combination of Valve-Regulated Lead-Acid (VRLA) battery and
Electrical Double-Layer Capacitors (EDLCs) can result into an extension of the battery life and
an increase of the energy efficiency and power capabilities. However, in [13] Omar et al.
underlined that the association with EDLCs is still expensive due to the high cost price of the
DC-DC converter.
In [8] Cooper et al. proposed a new technology, called Ultra Battery. This RESS technology
combines in the same battery cell the advantages of the EDLC and lead–acid batteries by using
an asymmetric approach. However, this technology is still in developing process and its real
performances are under investigation.
From the beginning of the nineties, lithium-ion technology has received considerable attention
due to the high energy density, power capabilities compared to VRLA, nickel-metal hydride and
nickel cadmium based technologies [20–34]. Due to the lowest standard reduction potential (E°
1