How it works

Battery Electric Vehicle

There is a fundamental difference between an electric motor and a petrol or diesel engine. Several types of electric motors can be used to propel the vehicles. Essentially, they can be divided in two groups: direct current motors and alternating current motors. Each category has its disadvantages and benefits. Motors can be build in different ways into the vehicle: front or four wheel drive; in wheel mounted motors, ...

Traction motors for electric vehicles must be fitted with a device to control the energy transfer between the battery and the motor. Today electronic traction controllers are used, which are characterised by both flexibility of use and high efficiency. Electricians call such controllers "choppers" for direct current drives, or "inverters" for alternating current drives.

The traction battery is the "fuel tank" of the electric vehicle, that is where the energy needed for driving is stored. It is also the most critical component of the vehicle. Through the years, several battery types have been developed. Only a small number however can be considered for use in electric vehicles; the most important types are the lead-acid battery and the nickel-cadmium battery. Other types are under development. Cycle life, energy and power density are important characteristics of EV's batteries.

The battery charger must transform the AC current from the network in a DC current of the correct voltage to recharge the battery. Volume and weight savings are particularly important for on-board battery chargers. Normal charge is the usual daily charging procedure. For road vehicle applications, it seems interesting to be able to charge the batteries in a much faster way. During subsequent charge and discharge cycles small differences will be emphasised between different battery elements. For this reason, it is necessary to apply a equalising charge at regular intervals.

Notably for the battery charge, the electric vehicle needs a specific fixed infrastructure. The electricity must be supplied by the electric mains. For the normal charging one needs an ordinary outlet, present in virtually every house. For larger vehicles, off-board chargers are mostly used. Connecting an electric vehicle to a charging post necessitates the use of a cable and plug. To avoid this manipulation, cable-free inductive charging systems are proposed.

Hybrid Electric Vehices

Hybrid electric vehicles are powered by both internal combustion engine and electric motor independently or jointly, doubling the fuel efficiency compared with a conventional vehicle.

Series hybrid system

Designed to extend the range of EVs on a single charge. The internal combustion engine is solely used to generate electricity.

Parallel hybrid system

Designed to increase fuel efficiency of ICE and to decrease exhaust emissions. The engine provides main propulsion, and the generator works in parallel to assist the engine to drive.

Series-Parallel hybrid system

Combination of series and parallel hybrid systems. The vehicle is powered by both ICE and a motor either independently or jointly.

Plug-in Hybrid Electric vehicles

Are a kind of combination between pure electric cars and hybrids. They have in fact a connection to the grid allowing overnight charging as well as a lager battery enabling the vehicle to run full electric on a long distance, like for example in city centre. It results lower environmental impact and reduced dependence on foreign oil sources.

Fuel Cell Electric Vehicle

FCVs are propelled by electric motors that run on electricity generated by combining hydrogen and oxygen in fuel cells. FCVs emit only water vapor and no toxic exhaust gases. They promise increased energy efficiency and performance comparable to the internal combustion engine vehicles. Fuel cells will also make for diversification of energy sources for they can use hydrogen produced from alternative fuels and renewable energy. A variety of innovative technologies of fuel cell is also expected to reinforce the industrial competitive power and foster new industries.

When water is decomposed by electricity, hydrogen and oxygen are produced. Fuel cells generate electricity by reversing this reaction, or combining hydrogen and oxygen in the air. As a result, only water vapor is emitted. Polymer Electrolyte Fuel Cell (PEFC) uses a polymer ion exchange membrane for an electrolyte, and operates at a relatively low temperature (about 80 o C), suitable for vehicles. Fuel cells are composed of cells. Like flat dry cell batteries, a fuel cell is composed of two (positive and negative) electrodes surrounding a solid polymer membrane (electrolytic membrane). Hydrogen and oxygen electrodes have many narrow grooves. Externally supplied oxygen and hydrogen react when they pass through the grooves.