Mercedes-AMG takes wraps off SLS E-Cell

TRUE to its word, Mercedes-Benz has unveiled a near-production version of its all-electric SLS AMG supercar as the German manufacturer works towards a 2013 market introduction.

Now dubbed the E-Cell, the eco version of the latest-generation gullwing is being developed under the ‘AMG Performance 2015’ strategy and has arrived in built-up form after the chassis was unveiled at the Frankfurt motor show last September.

In April, Mercedes-AMG chairman and managing director Volker Mornhinweg – who has since moved on to become the head of Mercedes’ vans unit – told GoAuto that it was preparing to show the all-electric supercar in near-production form as engineering and development work continued full-steam ahead, with a full production version expected on sale in 2013.

Now, the German performance division has obliged, revealing the SLS AMG E-Cell in working prototype form – and finished in unique fluorescent ‘AMG lumilectric magno’ paintwork.

“The gullwing offers the prospect of a possible small series production run and at the same time reflects the innovative strength and development competence of the AMG performance brand,” the company said in a statement.

Mr Mornhinweg’s replacement, Ola Kaellenius, who officially took the reins this month, added: “It is our goal to continually reduce the fuel consumption and emissions of new models in the coming years, while at the same time enhancing the core brand value of performance.” This SLS-based model rollout will begin in Australia next month as first deliveries of the $464,000, conventional-engine SLS arrive here, satisfying an order bank that is now at 52 units from a total 2010 allocation of 70 cars.

Mercedes-Benz Australia/Pacific has advised that a similar allocation is expected for 2011.

The first model designed completely in-house by Mercedes-AMG, the SLS is also still expected to spawn a convertible, while a smaller derivative dubbed the ‘baby SLS’ is widely anticipated to enter production around 2013, sans gullwing doors and drawing its power from the new direct-injection V8 engine family which includes twin-turbocharged 4.7-litre M278 and 5.5-litre M157 versions.

As GoAuto has reported, the SLS is powered by a 420kW/650Nm dry-sump version of AMG’s exclusive 6.2-litre V8, which drives the rear wheels through a seven-speed dual-clutch automated manual transaxle. It propels the super-coupe from 0-100km/h in a claimed 3.8 seconds, on its way to a top speed of 317km/h.

Fuel economy is rated at 13.2L/100km, while its official CO2 emissions output is 308g/km.

The zero-emissions E-Cell, on the other hand, uses four electric motors positioned near the wheels, with one transmission per axle transmitting the power. The combined peak power output is, as outlined at Frankfurt last year, 392kW, while maximum torque is 880Nm “available virtually from a standstill”.

Acceleration from 0-100km/h has now been confirmed at 4.0 seconds – just shy of the regular model – and Mercedes promises no interruption of tractive power with the spontaneous torque build-up and “confident power delivery”.

Driving dynamics are also “guaranteed” to be “at the highest level” with the all-wheel drive arrangement.

The liquid-cooled lithium-ion battery is described as a modular unit with an energy content of 48kWh and capacity of 40Ah. In order to optimise weight distribution and keep the centre of gravity low, battery modules are located in various locations, including in front of the firewall, in the centre tunnel and behind the seats.

The battery unit comprises 324 lithium-ion polymer cells, which have a maximum electric load capacity of 480kW – said to be the “absolute best value in the automotive sector”.

The other feature Mercedes highlights is the “intelligent” parallel circuit of the individual battery modules, which is said to maximise the safety, reliability and service life of the 400-volt battery.

While the electric drive components required no changes to the SLS’s aluminium spaceframe, the addition of front-wheel drive has seen the front axle redesigned.

Rather than stick with the double-wishbone front axle, Mercedes-AMG engineers have installed a multi-link suspension with pushrod damper struts. The damper struts are also now horizontally arranged, rather than vertically, to make way for the additional drive shafts.

Other mechanical variations include the employment of electro-hydraulic power assistance – rather than just hydraulic – for the rack-and-pinion steering gear, while electronic systems such as ABS and ESC have been recalibrated to match the full-time 4WD characteristics.

Like the regular SLS, braking hardware on the E-Cell includes AMG ceramic composite brakes, with the rotors measuring 402x39mm up front and 360x32mm at the rear.

The AMG light-alloy wheels feature a new smooth-surfaced design, although the spec remains at 9.5x19 inch (front) and 11.0x20-inch (rear), with 265/35 R19 and 295/30 R20 tyres at the front and rear respectively.

The exterior on the E-Cell prototype carries a number of modifications, such as redesigned full-LED headlights (with integrated daytime running lights) which require less power than the regular bi-Xenon system used on the standard SLS.

The grille has transverse slats instead of a diamond pattern, and the air outlets on the bonnet and vehicle sides have been modified for enhanced aerodynamics.

The front apron has also been brought forward to improve air resistance while reducing downforce. Complementing this is an extendable front splitter, which in parallel with the automatic rear spoiler, extends downwards by 7cm at speeds above 120km/h.

With no exhaust system, the rear diffuser is more steeply angled to provide extra downforce at the rear axle.

All trim and detachable parts are finished in matt black compared with the chrome or silver shadow on the regular SLS.

Inside, the instrument cluster and centre console have been reworked to accommodate additional information required with an EV, such as battery charge status. The dash stack houses a 25cm touch-screen, which can be used to obtain information on the flow of power from the four electric motors, along with audio, climate and navigation functions.

The E-Cell also features a unique black-and-white nappa leather colour combination, used throughout the cabin.