World Electr. Veh. J., Volume 3, Issue 4 (December 2009) – 26 articles , Pages 670-889

Battery powered cars have many merits over traditionally powered cars: they are more energy efficient (i.e. less GHG emissions), less polluting and quiet.
However, not all electric cars are the same and there is a ‘break point’ at a range of around 50-75 miles. Up to this range battery packs can be made affordable, compact and manageable in size and weight. Vehicles with this range are already produced today at affordable prices and do not need dramatic technology breakthroughs. Nevertheless, in the popular media and among commentators and politicians there is a sense that such vehicles are not an adequate replacement for traditional ICE powered car’s long range, fast refuelling and high performance. Such a view ignores the potential of small BEV’s to deliver adequately and economically on the actual mobility requirements of the majority of the population.
In the United Kingdom the average car journey is only 8 miles long and the average speed is only 24 mph. This suggests that the capabilities of most current cars are vastly in excess of their actual requirement. This apparent paradox is easily explained by a brief look at the price list of a typical car manufacturer’s range. By the nature of the global, large scale car production process the marginal costs of extra performance, space and features is relatively small. The free market and consumerism do the rest.
These economics do not apply to BEVs where the cost of the energy storage system imposes a large cost on vehicle size, performance, range and features. This paper concludes that smaller, short range BEVs are nevertheless such good match to actual consumer mobility needs and have so many societal advantages that the economics of carbon pricing and fuel price rises already make them cost competitive with traditional ICE powered cars in selected markets. As consumers re-evaluate how much they are prepared to pay for range and performance in particular, they are likely to opt for vehicles that match their actual needs at an affordable cost. Therefore small BEVs specifically should be encouraged as a means to create affordable and clean access to individual mobility in the shorted possible timescale. Full article

The motivation of this analysis is the need of high efficiency and high power density permanent magnet synchronous motor (PMSM) drives for use in electrical vehicle power trains. It is clear that the chosen electrical steel for the lamination stack plays an important role, but proper quantification is missing. The purpose of this paper is to formalize the problem of selecting the optimal steel grade for the construction of PMSM’s. This question is important to steel producers, not only for helping customers selecting the most appropriate existing grade for their application, but also for defining the strategic orientation of the further R&D of enhanced electrical steel grades. The notion of steel efficiency is defined and, after describing the FE implementation of iron loss models, a methodology for material optimisation is proposed. Full article

Trolleybuses and electric mini-buses in the Portuguese city of Coimbra are one of the main forms of daily transportation of its many citizens. As part of CIVITAS MODERN European Project — MObility, Development and Energy use ReductioN, one of its main objectives for Coimbra is the integration of clean production electricity system owned by the City Council, able to supply the energy to the trolleybus traction lines, plus electric energy to charge the batteries of the electric mini-buses fleet. This electric fleet is undergoing a significant expansion in the near future. A study was carried out in order to evaluate the potential of renewable energy production to supply the electric fleet public transportation in Coimbra, reducing the necessity of fossil fuels and associated emissions, therefore improving the air quality. The electricity source will be a low head hydro potential, using an already existing dam-bridge, where a group of turbine-generators units can be placed, with modest operation costs and reduced civil works with small environmental impact. The optimization of the renewable energy generation is also assessed as a function of the load profiles. Full article

Significant efforts are put worldwide on developing new concepts for vehicle propulsion with the hybrid electric vehicle (HEY) being a prominent example. Hybrid technology is clearly a strategic future activity for automotive industries and in response to the rapid development in the area; the Swedish Hybrid Yehicle Centre (SHC) was formed in 2007 to join forces between Swedish industry and academia in the field. The centre emphasizes a holistic view to meet the environmental and societal needs with new technological solutions. The research within SHC is currently divided into three different themes whereof we here describe the Energy Storage theme with emphasis on the activities carried out at the involved universities in the current main project areas: Cell Properties, Electrode Materials and Electrolyte Additives. Examples are given on how these projects attacks the problems at hand separately, but also how we create synergy effects between the projects. As an example cell modelling is performed given a specific chemistry and cycling scheme, the same parameters are used for electrochemical experiments which provide macroscopic data that are connected with molecular level actions in the electrodes, the electrolyte, and the interfaces. All this is done using our base-line chemistry and a subsequent route is to investigate the role of different additives to overcome the limitations that are observed. Full article

The U.S. Army TACOM-TARDEC developed and validated a high-fidelity six-degree-of-freedom model to use in a trade study for the development of a prototype autonomous vehicle. The model captures realistic dynamics of the six-wheeled, skid-steered vehicle along with the electrical, thermal, and mechanical response of a detailed series hybrid-electric power system with in-hub drive motors, lithium-ion battery, and generator linked to a diesel engine. These components were modeled and integrated via extensive power and energy component libraries developed for use with a high-fidelity software tool for dynamics modeling. Further, the vehicle model’s entire complement of components was integrated in a flexible configuration that allowed them to be readily adjusted or swapped out so the user could use the model to ascertain the relative effects of modifying the vehicle’s structural or power system components on specific vehicle evaluation criteria. Such criteria include the vehicle’s performance with high-speed stability, skid steering stability, body pitch/roll/dive/squat characteristics, braking capability, road/soft-soil traversal, and steering maneuverability.
The model captures both the on- and off-road mobility for the vehicle via use of an extensive library of various terrains including hard surface, sand, sandy loam, clay soil, and snow. Further, detailed waypointbased path navigation routines automate the vehicle’s traversal over a number of user-selectable courses including some established military courses such as Churchville-B, Perryman 1, 3, and A, and Munson with user-defined vehicle velocities. The model functions as an executable file run independent of any proprietary or close-source software; the user utilizes a simplified interface to vary any of the variables associated with the vehicle’s geometry, power system, course and speed to navigate, and terrain type applied to the course. The graphical view for the vehicle traversing the selected terrain is shown with an open source 3D graphics tool. The model was validated by applying the specifications in the model for the prototype vehicle of the first-generation of autonomous six-wheeled skid-steered vehicle, simulating the model in maneuvers identical to those the prototype vehicle performed, and comparing the simulated and actual results; the data matched and the model was successfully validated.
The vehicle model was designed primarily for the trade study for the design of a specific vehicle, but was created with sufficient flexibility and capability for modeling future vehicles as well. The interchangeability of the vehicle models’ components and environments allow a user to modify or replace the vehicle’s power system components, chassis masses, tires, transmission, duty cycles, courses to traverse, and many other aspects of the vehicle. Thus the user can essentially model any vehicle with similar types of components or structures and use that model to determine the impact of those elements upon many vehicle design considerations such as mass requirements, volume constraints, power system requirements, wheels design, suspension characteristics, and controls. Several new vehicle models are already being developed using this model’s flexibility and capability. Full article

In this study, a control strategy for the series hybrid electric vehicle (SHEV) powertrain, based on the design of fixed-boundary-layer sliding mode controllers (FBLSMCs) and a battery charge scenario, is presented to enhance engine efficiency as well as extend battery cycle life. An appropriate battery charge scenario is designed to remove surge charge current, keep the battery staying in a high state-of-charge (SOC) region and avoid persistently-high charge power, which are positive factors to the battery lifetime extension. To locate the engine operation in the optimal efficiency area, two robust FBLSMCs against uncertain disturbances are configured in the powertrain control system, responsible for engine speed control and engine torque control, respectively. Simulation results are obtained for comparison between the proposed and conventional powertrain control schemes by using the Advanced Vehicle Simulator (ADVISOR). Through these simulations, the effectiveness and superiority of the FBLSMC-based SHEV power train control strategy are validated. Full article

ConocoPhillips has engaged in research and development of carbonaceous materials as anode material for lithium ion batteries for the past 10 years and developed a technology platform for producing graphite anode materials for Li-ion batteries (Li-B). The CPreme^® graphite powders were developed as anode material for Li-ion batteries, specifically addressing the challenging needs of Li-B in automotive and other high-power applications. The CPreme^® graphite powders provide excellent combination of power, energy density, long cycle life and safety. This presentation provides details behind the technology platform used in making CPreme^® graphites. Examples of how CPreme^® graphites can help the LiB manufacturers meet the difficult requirements of future automobiles are discussed. Full article

An analytical simulation algorithm is developed to estimate driving performance of power train system of an electric vehicle that is propelled by the electric energy storied in a rechargeable battery. The principal theory is conservation of energy and several analytical and experimental data such as rolling resistance, aerodynamic drag, mechanical efficiency of power transmission etc are incorporated to have the simulation algorithm for the general driving performance of an electric vehicle designed. From the analytical calculation results, running resistance of a designed vehicle is obtained with the change of operating condition of a model vehicle such as inclined angle of road and vehicle speed. Tractive performance of a model vehicle with a given power train system is also calculated at each gear ratio of transmission. Through analysis of the two calculation results: running resistance and tractive performance, the driving performance of a designed electric vehicle is obtained and it will be used to evaluate feasibility of the designed power train system on the model vehicle designed. Full article

To assist in combating global warming and to respond to energy issues, Honda has developed the FCX Clarity, a new fuel cell vehicle that displays significant improvements in driving performance and fuel efficiency against previous FCX Models, and which achieves a level of appeal unrivalled by reciprocating engine vehicles. The key to the development of the new vehicle was the reduction of the size and weight of the fuel cell powertrain.
Honda’s unique V Flow FC stack technology is the core of the FCX Clarity’s fuel cell powertrain. A considerable reduction in size and weight and increased power have been achieved, with the powertrain as a whole displaying a weight output density that is 2X higher and volume output density 2.2X higher than that of the previous FCX.
The maximum power of the V Flow FC stack employed in the Clarity has been increased to 100 kW. The new FC stack also achieves a 50% increase in volume output density and 67% increase in weight output density against the previous stack. Low-temperature start performance has also been significantly improved, with the vehicle able to be started at -30 °C.
A new design has increased the maximum power of the drive motor to 100 kW and resulted in the achievement of a smooth, powerful and continuously extendable acceleration feel.
Increased efficiency in the powertrain and superior energy management have enabled the realization of an energy efficiency of 60%, resulting in a level of fuel efficiency 2.1X higher than that of a small gasoline vehicle and 1.4X higher than that of a small hybrid vehicle. Full article

Optimization routines for battery, supercap and fuel cell stack in a fuel cell based propulsion system face two problems: the tendency to cycle beating and the necessity to maintain identical amounts of stored energy in battery and supercap at the start and end of the driving cycle used in the simulation. A method is proposed to reduce these problems. The proposed method characterizes driving cycles and generates alternative cycles with an arbitrary length from an existing cycle, based on the characteristics of the original. The method is demonstrated with an existing driving cycle for buses and validated with measurements from a trolley bus in the region of Arnhem, the Netherlands. Full article

Being able to predict the behaviour of Rechargeable Energy Storage Systems (RESS) such as batteries and Electric Double-Layer Capacitors (EDLC) relies on the models used to represent them. Research on the development and enhancement of these models is performed on two tracks: on one hand by defining the model topology, where a trade-off is sought between the reduction of components in the model equivalent scheme and the ability of the model to describe all potential system behaviour and, on the other hand by improving the method of calculating the magnitudes of the different components in the model. The storage devices examined in this paper are divided in two groups, electrochemical devices and electrical double layer capacitors. The first group consists of lead-acid, lithium, Ni-Cd and Ni-MH batteries. The second group comprises of Electric Double-Layer Capacitors (EDLC). For every model used to describe a battery or EDLC, different techniques are implemented to calculate the magnitude of the components. The work presented in this paper will elaborate to the calculating method used in NREL's FreedomCAR test-manual adapted to fit different battery- and EDLC models. This method consists of an iterative approach to the equations of the model using data gathered from performing tests on the battery or supercapacitor. Validation of the models obtained through this calculating method will be done by performance tests on the storage devices. As the models of batteries and supercapacitors are a key aspect in the simulation software for hybrid-vehicles more accurate models result in more accurate simulations. These simulation programs depend upon the underlying component models, the data generated by which determines the accuracy of the program's data-output. The availability of reliable storage RESS models will thus be a key element in to allow overall vehicle modelling. Full article

The paper discusses a simulation platform developed in Matlab/Simulink suitable for the modelling and analysis of combined energy sources and components considered for electric vehicle power trains. While there are a number of similar simulation tools in literature, the simulation model elements each have suitable resolution to model detailed dynamic operation, an important consideration when assessing the specification requirements for the interconnection of multiple electrical components and their associated interface power electronics. Models are presented for a number of vehicle power-train components that can be interconnected to investigate alternative energy sources and power-train components proposed for electric vehicles, the combination of which is undertaken to exploit their various attributes. In particular, the paper considers the combination of an energy dense ZEBRA battery and power dense supercapacitor. The energy dense source is specified and operated to fulfil the requirements for vehicle range, while the power dense source provides the peak power for acceleration or regenerative braking and to help improve the regulation of the vehicle dc supply. Full article

Interest to hybridize mobile work machines has increased substantially during ongoing decade. Reasons for increasing interest are mainly tightening emission regulations and trend of rising fuel prices. To get better understanding for the benefits of hybridization, Helsinki University of Technology (TKK) has started 5 years project to research different aspects, how to improve fuel economy in mobile work machines. For case work machine is chosen an underground mining loader which will be first researched as conventional version and then it will be converted to a hybrid version. The tests for conventional version were done in the early 2009 and for hybridized version till the end of 2010. The results will be then compared to each other. Full article

Scientific papers usually do not present ‘lessons learnt’ results, what comes to engineering aspects in vehicle design. A lot of valuable information is collected during research and prototyping projects, but this is not shared in public often enough. This paper is a general discussion about the engineering matters related to the implementation of hybrid systems in mobile work machines. The target of this paper is to underline the importance of paying attention of these matters already in very beginning of the research and development.
The discussed aspects are related to the energy transmission, packaging of components, vehicle assembly and service. The energy transmission section compares benefits and drawbacks of hydraulic and electric transmission implementations. Packaging of components presents some issues to pay attention to when accommodating components into vehicle. Service aspect highlights the benefits and drawbacks of different solutions in maintenance operations.
The discussion is limited to explain only differences and analogies between hydraulic and electric components. The cost factors can be estimated only by the reader, because they are very case sensitive. The key factor is number of machines made in serial production. In case of passenger cars the cost structure is very different compared to small series mobile work machines. Full article

The HIDROCAT is an all electric small ship that uses energy from three sources, namely: the hydrogen stored on board via fuel cells, the solar energy and energy stored on batteries. In this sense, it is a hybrid propulsion system composed of two electric motors, a system of lithium batteries, a hydrogen fuel cell and photovoltaic cells. A control unit does the management of the energy fluxes. The objective is to maximize the use of solar energy, therefore the system of batteries is important to store the converted solar energy when it is not immediately used by the motors. The hydrogen fuel cell guarantees that energy is available on board at the expense of a relatively small weight when the solar irradiation is insufficient due to intensive use of the motors for long periods, or when the solar irradiation is low.
The concept described above is implemented in a preliminary project of a tourist catamaran and it is demonstrated that not only the operational requirements are accomplished by the project, but also that a demonstration project can be implemented with the existing technology. The preliminary design includes the hull bodylines, propulsion system, general arrangement, weight estimate, vessel speed, and autonomies. Several scenarios of operation are investigated for the Alqueva Lake in Portugal and it is concluded that the Hidrocat satisfies the design requirements in terms of autonomies. Furthermore, it is concluded that if the operational scenario is not very demanding, during summer the vessel may carry out its mission using solar energy only. Full article

Energy systems operation in isolated areas is frequently based on imported fossil fuels, which is a problem in different dimensions including environmental, economic and security of supply, with the latter being particularly relevant for any isolated system like Islands. Renewable energy is regarded as a solution to this problem, mainly in its transformation to electricity. This, however, excludes the impact of the transportation sector that represents a significant component of the imported fuels consumption. Other main limitation associated to renewable electricity consists on the need to increase the storage capacity that might attenuate the effect of intermittence of renewable energy sources and the disparity between supply and demand. In both problems - that are associated with renewable energy management - Plug-in Electric Vehicles (PEV) could be a part of the solution in that the use of vehicle to grid (V2G) technology can provide storage of electric energy during low demand times and use it to match the demand in peak hours and/or to avoid fossil fuel consumption.
Therefore, some of the main questions are: could the large scale PEV penetration lead to increases in the fraction of electricity produced from renewable? Is the usage of PEV batteries as a storage system truly the best solution?
São Miguel Island is the main electricity consumer in the whole Azores’s archipelago. There is no power connection to any major grid or even with other Islands. This work analyses a case study of isolated electricity grid, where energy systems modelling is used to assess to different roll out scenarios for large scale PEV penetration and discuss the possibility to increase the potential for the use of renewable electricity. Full article

In order to satisfy the growing expectation for energy efficient eco-friendly transportation a number of vehicle concepts have emerged, including the hybrid electric vehicle (HEV) and battery electric vehicle (BEV). Vehicle dynamics necessitate careful sizing of onboard energy storage systems. As the penetration of electric vehicles, in both the public and private sector increases, the requirement to facilitate and utilize them becomes paramount. A particular class of vehicle, the plug-in hybrid-electric vehicle (PHEV) also poses a greater challenge to existing terrestrial based electrical supply systems. This paper of discusses the various future vehicle concepts and investigates the potential impact of PHEV’s and BEV’s fleets on the local electricity networks in the UK. Full article

In this article the development and use of a data acquisition system for the optimization of hybrid propulsion systems is proposed. This versatile system can be used for different hybrid driveline architectures and for off- and on-road data logging. It retrieves the necessary parameters to develop or assess the power flow control algorithm of the vehicle under test, in order to optimize the driveline and reduce energy consumption and emissions. It is based on a cRIO^TM programmable controller of National Instruments in combination with dedicated sensors and interfaces for the data acquisition of electrical and mechanical parameters. The assets and configuration of the system are discussed. Experimental data are given and discussed. In addition the HEV simulation platform developed in parallel is briefly described. Full article

The bipolar design consists on identical cells which are stacked together. This technology offers several advantages because it simplifies cell-to-cell connections and so offers a lowering internal resistance for the whole battery. The bipolar battery can be designed to present a large capacity, a high voltage and an appreciable flexible form factor.
The patented bipolar battery developed in CEA for the Hybrid Electric Vehicle (HEV) is based upon the use of Li₄Ti₅O₁₂ as anode material (allowing the use of a common bipolar aluminium current collector, and high power application) and LiFePO₄ (cycle life, safety, low cost). The main target has been first to achieve a sealed system with no electrolyte leakage, and then to demonstrate the advantage of the Li₄Ti₅O₁₂ / LiFePO₄ couple (1.9V) for high power Li-ion bipolar battery. To increase the battery cycle life, a new design has been elaborated and has allowed to develop standard energy battery of 15Wh (24V, 0.65 Ah).
In this paper, first results on 15Wh cells, using the Li₄Ti₅O₁₂ / LiFePO₄ couple and a new bipolar battery design, will be presented according HEV profiles. Full article

Electrochemical capacitors (SC) are receiving increasing attention as possible enabling technologies in applications where high power is required for short times, such as in hybrid vehicles (HEV) and uninterruptible power systems (UPS). Moreover, there are some applications using fuel cells (FC) as power generators, whose energy efficiency is greatly reduced whenever FC power variations are significant. In 2005 the European Commission (EC) funded the ILHYPOS project, mainly aimed at the research and development of innovative SCs with highly improved specific performances (specific energy and power), and based on environmentally acceptable materials, such as ionic liquids, a novel electrolyte class of materials, with a working voltage in excess of 5 V. The improvements of SC performances were pursued also studying new electrode materials and/or cell designs: specific energy in excess of 40 Wh/kg, based only on active material weights have been estimated, in configurations with electronic conducting polymers or activated carbons in asymmetric configurations. As part of the Project ILHYPOS, the possible impact of the studied SCs has been evaluated by means of simulations in defined applications, such as those in fuel cell vehicles (FCV) and UPS, powered by fuel cells. The simulations for vehicle applications have been performed by using conventional standardized and real duty cycles. The sizing of the ILHYPOS SCs has been carried out with developed mathematical models and applied to a FC hybrid electric van, a test prototype developed by an Italian small enterprise. This paper first highlights the most recent achievements of the ILHYPOS Project and, then, presents the impacts of the developed SCs with respect to commercial SCs and a drivetrain with and without SCs. Full article

The energy storage system is one of the key components of any electric vehicle powertrain. When lithium based energy storages are used it is important to investigate carefully the safety aspects, because the safety and cost were the main aspects which prevented the introduction of lithium ion in automotive application. This work describes the methods adopted in arsenal research for developing energy storage system for advanced electric power-train. The focus will be on lithium ion battery technology. The correct cell selection and its performance assessment could ensure the achievement of a performing and inexpensive energy storage system. But for ensuring the harmless of the energy storage system a safety concept and a consequent design should be also present. The present work shows the different requirements to take into account for the energy storage system design during the development of HEV and EV vehicles within arsenal research laboratories. Particular attention is given to the abuse conditions and their corresponding test methods during the development phase. The paper presents the safety concerns regarding the short circuit, its measurements method and the failure pathways. Results of short circuit abuse tests are analysed and indication regarding the design is given. Full article

In this paper, an intelligent electric power steering system is proposed to replace a traditional hydraulic power steering system and implemented in a real light hybrid electric vehicle. An intelligent fuzzy control algorithm is applied to yield basic assist logic, return compensation logic, damping compensation logic, and inertia compensation logic in an assist steering system. According to steering wheel angle and vehicle speed, the proposed fuzzy inference logic can provide needed assist motor current. Under experts’ knowledge of fuzzy control, the electric power steering system can satisfy smooth driving. In addition, four driving modes are designed to complete the control strategy. Different driving modes have corresponding fuzzy inference strategies to complete the assist and compensation logic. Finally, the intelligent electric power steering system with a new 12V/500W EPS motor is applied in a real light hybrid electric vehicle. Experimental results demonstrate that the proposed method is reasonable and feasible. Full article

Internal resistance is usually calculated by EIS (Electrochemical Impedance Spectroscopy) method, which gives unrealistic low internal resistance values. In this paper internal resistance will be calculated from the voltage drop with FreedomCAR method where the validation of the results is much better (99%) than EIS method[1][12]. Batteries are often tested per cell. But in most cases more than one single cell is needed for an application and the characteristics of a module of cells is not the same. In other cases the whole module is examined as one big cell, without looking on the individual cells. But the weakest cell affects the performance of the whole module. This research goes deeper than the module approach on batteries: the behavior of individual cells is examined while they are working together in a module. The battery model consists in most researches of an ideal voltage source and a simple internal resistance[2]. In this work the advanced FreedomCAR battery model, created by Idaho National Laboratories (USA), is used: the cell is represented by an ideal voltage source with two internal resistances and two capacitors. Usually batteries are tested with very low constant currents (till 5% of the nominal current value) to show a high capacity value to the customer, while the customer needs the characteristics of the battery in real conditions. Here the parameters are calculated by testing the battery packets in high pulse conditions. The matching between the predicted and the measured voltage is proportional with the quality of the model. This was 99% (+-0.9%) in the tests. This means that the model is very close to the reality. Three types of Lithium-ion battery packets with 6-7 cells were tested. Full article

Nowadays car development time from concept approval to Job 1 is between 2 and 5 years (with an average of 3 years), but in the coming years is necessary to reduce it in order to achieve the optimal 12-month car. On the other hand the penetration rate of alternative powertrains (electric, hybrid) is growing quickly, increasing the complexity of the vehicle and therefore development time cycle. Presented architecture and methodology in this paper, is based on virtual modelling of system/components, giving the possibility of an integrated vehicle virtual simulation, and also allowing the substitution of system/component models for real hardware (Hardware-In-the-Loop, HiL), or even using the entire vehicle model in a driving simulator searching for Human-In-the-Loop (HuiL) approaches. As far as the modelling represent the real system/components with accuracy, the use of these vehicle integrated virtual models will be more useful, allowing reduce the development time and also increasing vehicle overall quality. Full article

The design of a full electric vehicle (or battery electric vehicle (BEV)) requires the development and optimization of a complete electric powertrain, including battery, power electronics, electric machine, sensors and control system.
When designing an electrical platform, from the very beginning of the V-cycle, it is mandatory to rely on modelling and simulation tools in order to drive the main choices and then to optimize the system. This paper presents an electric powertrain simulation platform developed with Matlab-Simulink, dedicated to multiphysic optimization of the system.
As an example, the basic electrical powertrain architecture first considered in this paper includes a battery, an inverter, a dc-dc buck converter supplying motor inductor and a wound rotor synchronous machine (WRSM). The purpose is to show how simulation tools can help in comparing different powertrain control strategies.
The present simulation platform is also useful to study physics architecture. To illustrate this point, another electrical architecture is also presented, including a dc-dc boost converter between battery and inverter. This structure must be considered here as an example only in order to show how to optimize control laws taking into account various criteria, including architecture ones. Simulation results are compared for both architectures in terms of powertrain performances and range. Full article

With the current state of technological development, the future of Electric Vehicles (EVs) seems to go through the hybridization of various Energy Storage Systems (ESSs). This strategy seeks to benefit from the best qualities of each available energy source, and is especially useful in urban driving. In this work, the need for multiple energy sources hybridization is addressed. A methodology to optimize the sizing of the ESSs for an electric vehicle taking as example the ISEC-VEIL project, using different driving cycles, maximum speed, a specified acceleration, energy regeneration and gradeability requests are presented. It is also studied the possibility of using a backup system based on solar energy, that may be considered in the design, or as an extra to cope with unforeseen routines and to minimize the recharge of ESSs. Some simulation results of multiple energy sources hybridization are presented, considering different ESSs and different scenarios for the small presented EV, in order to verify the proposed designs. Full article