Described as the family electric car for urban areas: the compact five-seater with battery-powered electric drive offers a range of more than 124 miles. Its introduction follow the B-Class F-CELL fuel-cell car as the second electric car built in series-production conditions.
A total of 500 A-Class E-CELL cars will be built at Rastatt, Germany from autumn 2010. The vehicles will be leased to selected customers in several European countries, including Germany, France and the Netherlands. Based on the five-door version of the current Mercedes A-Class, it features generous interior space and luggage compartment for maximum versatility. Ther have been no compromises in terms of space and variability, with compact batteries located in a well-protected and space-saving way under the vehicle.
The car's two lithium-ion batteries provide a range of over 124 miles (NEDC). It is powered by a quiet, emission-free electric drive with peak output of 95hp, developing a high torque of 214 lb-ft.
Along with safety, comfort and suitability for daily use, the A-Class E-CELL also offers agility and driving pleasure. The features are based on a low center of gravity, partly the result of the batteries being under the passenger compartment, in the "sandwich" structure of the vehicle floor. This gives the car excellent road-holding and handling characteristics. Another benefit from this installation location is the provision of best-possible protection against the intrusion of structural components in the event of a head-on collision or impact from the rear. This is because the batteries are located outside the vehicle body's deformation zones. The high-stability characteristics of the sandwich structure of the floor also provide outstanding protection for both battery and passengers in a lateral collision. The electric drive of the A-Class E-CELL is a permanent-field synchronous unit developing a peak output of 95hp, a continuous power rating of 68hp and a high maximum torque of 214 lb-ft. This makes the A-Class E-CELL a dynamic performer on the road, taking just 5.5 seconds to accelerate from 0-37mph. A kick-down function is used to deliver maximum acceleration, according to the current charge level and battery temperature. Maximum speed is electronically set at 93mph.
The energy storage units are two high-performance lithium-ion batteries based on high-voltage technology. The advantages of lithium-ion batteries include their compact dimensions and significantly higher efficiency in comparison with nickel-metal-hydride (NiMH) batteries. They offer 30 percent more energy density than NiMH technology, and 50 percent more power density. Other benefits include high charging efficiency and a long service life. The combined energy capacity of the two lithium-ion batteries is a total of 36 kWh. With fully charged batteries, the A-Class E-CELL has a range of over 124 miles (NEDC).
A special thermomanagement system keeps the high-voltage batteries cooled to within an optimum temperature window. The cooling system is based on a low-temperature cooling circuit. Fluid cooling with a water-glycol mixture ensures a stable operating temperature supporting the high degree of efficiency and the longevity of the energy storage. In high ambient conditions, the battery cooling system is boosted with the coolant circuit of the air-conditioning system. The electrical drive system and two on-board chargers are cooled with a high-temperature cooling circuit. This circuit keeps the units working at optimum operating temperatures, with maximum power delivery from the drive system. The car's power electronics supply the 12-volt vehicle electrical system via a DC/DC converter with electric current from the high-voltage system. The electronics system also controls other functions such as the heating and air-conditioning systems in order to minimize the load placed on the battery for this purpose.
The batteries can be either replenished at public charging points or plugged into an ordinary household power socket. A range of charging options are available, including single-phase 230-volt sockets, three-phase sockets in a household wall-box, and public recharging points.
Using a single-phase 230-volt network, it takes around eight hours' charging time to accumulate the energy required for a range of 62 miles (NEDC). This time is reduced to just three hours in the case of charging from a wall-box or at a roadside recharging point.
Daimler and a number of other European automakers and energy utilities have agreed on standardized charging plugs and sockets, with an ultimate aim of worldwide standardization. This makes the technology more customer-friendly, and is seen as a key prerequisite for the rapid spread of electric mobility.
Like the smart fortwo electric drive in its category, the A-Class E-CELL is the world's first vehicle in its class to be fitted with an intelligent charging management system based on "SmartCharge Communication". Via the vehicle electronics system, all relevant information - such as the electricity supply contract identification data - is exchanged with the charging point. Benefits include a convenient, simple and totally reliable billing system. Other intelligent features of the car include pre-start climate control. While the A-Class E-CELL batteries are being charged at home or at a roadside charging point, the interior can be pre-heated or cooled to a temperature set by the driver. Another function enables the driver to monitor charging progress and therefore the present range available, via the internet or a smartphone, for example.
The A-Class E-CELL electronics also provide for proactive control of the charging operation. So if the electric car is parked for a long period, recharging can be set to take place at times when electricity is cheaper, for example during the night. The intelligent interface in the A-Class E-CELL provides a range of billing, control and monitoring functions, making electric mobility convenient and safe, and therefore very customer-friendly. The vehicle is automatically immobilized on connection of the charging cable to the socket, preventing any possibility of driving off by mistake while charging is in progress. This makes the recharging operation even safer and more convenient for the user.
In line with the strategy used for hybrid development, Mercedes engineers have also developed a modular system for electric vehicles with battery and fuel-cell. The benefits include the efficient use of shared parts in all the brand's electric vehicles. All the key components of electric cars are appropriate for a modular approach - for example, the electric drive of the A-Class E-CELL is also used in the B-Class F-CELL. Both energy storage units in the electric A-Class are the same as the battery in the smart fortwo electric drive.