At first glance, the Formula One Silver Arrow and the Mercedes-Benz SLS AMG E-Cell with its gleaming yellow paintwork seem to have little in common. The Silver Arrow has aerodynamic wings at both front and rear while the SLS AMG E-Cell has two gullwing doors and a roof. Yet beneath the yellow bodywork slumbers a piece of sophisticated F1 technology – some of the expertise that went into the construction of the SLS AMG E-Cell also made the crossover into Michael’s and Nico’s Formula One cars.
This zero-emission super sports car is powered by four synchronous electric motors generating a maximum output of 392 kW and maximum torque of 880 Newton metres. The four compact electric motors have a maximum (rotational) speed of 12.000 revs per minute. Each axle has its own transmission.
The SLS AMG E-CELL accelerates from nought to 62mph in just 4.0 seconds. This puts it almost on a par with the 42kW (571bhp) SLS AMG whose 6.3-litre V8 engine takes it to 62mph from a standing start in 3.8 seconds. Unlike the combustion engine, torque build-up with an electric motor is instantaneous – maximum torque is available virtually from a standstill. Just like in Formula One, the transmission is absolutely smooth, delivering power without any interruption to traction.
Technology transfer in both directions
The electric transmission of the SLS AMG E-Cell has been a joint development project since 2010 between AMG and Mercedes AMG High Performance Power Trains in Brixworth. This has allowed the F1 engine experts to draw on their experience with and knowledge of the KERS hybrid system which made its debut in the top flight of motor racing in the 2009 Formula One season. In the 2009 Hungarian Grand Prix, Lewis Hamilton made history by winning the first ever race in a Formula One car with KERS – in this case, the Mercedes-Benz KER system
The SLS AMG E-CELL drive incorporates a liquid-cooled high-voltage lithium-ion battery featuring a modular design with an energy content of 48 kWh and a nominal voltage of 400V. The maximum electrical output of this high-performance battery is around 480 kilowatts – a rating that is unmatched in the automotive sector. As in Formula One, The 400-volt battery is charged by means of targeted recuperation during braking whilst the car is being driven.
The additional front-wheel drive called for a newly designed front axle with pushrod damper struts. The horizontal damper struts are operated via separate push rods and transfer levers.
Lightweight thanks to experience with carbon
The electric powertrain is not the only area in which there has been a transfer of technology between racetrack and road. For example, lightweight composite materials which have their origins in Formula One are used in the construction of the SLS AMG E-Cell.
Its key element is a transmission tunnel made out of lightweight carbon-fibre composite material (CFRP), which is structurally integrated into the aluminium body shell and firmly bonded with it. The high-strength and stiff CFRP component helps to reduce weight, while also serving as a monocoque housing for the battery modules.
CFRP components are up to 50 percent lighter than comparable steel ones, yet retain the same level of stability. Compared with aluminium, the weight saving is still around 30 percent
Through their experience with the SLR, the vehicles in the AMG Black Series and in motor racing (including Formula One and the DTM), Mercedes-Benz and AMG have accumulated more than 10 years of expertise in working with carbon-fibre materials – this stands the gullwing in just as good stead as for other Mercedes models that go no further than the local supermarket.