The car we originally came to know as the Megacity Vehicle was officially revealed today as the BMW i3 Concept ahead of its 2011 Frankfurt Motor Show debut and less than two years before it goes on sale in 2013.

The new i3 along with the i8 sports coupe concept (we’ll have more on that in a bit) that was also shown today, are the first vehicles of BMW’s new i sub-brand with which the Bavarian company plans to sell a range of environmental-friendly hybrids, pure-electric and range-extended cars.

The upcoming i3 will be BMW’s first ever mass produced all-electric model. The five-door hatchback rides on a new dedicated architecture named “LifeDrive”.

The chassis is made mostly from aluminum while the body structure from CFRP (carbonfibre reinforced plastic). BMW says that CFRP is at least as strong as steel, but roughly 50 per cent lighter, adding that by comparison, aluminum would save “only” 30 per cent in weight over steel.

For its motivation, the i3 relies on an electric motor that resides over the rear axle and drives the rear wheels. It’s an improved version of the electric motor found on the MINI E prototype and it generates an output of 170-horses (125 kW) and 250 Nm (184 lb.ft) allowing the i3 to accelerate from 0 to 60 km/h (37 mph) in under four seconds and from rest to 100 km/h (62 mph) in less than eight seconds.

The single-speed gearbox allows the i3 Concept to reach an electronically governed 150 km/h (93 mph). BMW says that without the speed governor the driving range would be “unnecessarily restricted”.

The power to drive the electric motor is provided by a set of lithium-ion batteries with a liquid-cooling system that are mounted within the central section of the floor. They can be fully recharged in six hours using a standard power socket. If a high-speed charger is used, an 80 per cent charge can be achieved in one hour. The batteries offer a driving range of around 120km to 160km (80-100 miles).

BMW will also offer an optional Range Extender called the REx, which allows the electric driving range to be increased. The REx comprises of a small displacement petrol engine that drives a generator which maintains the battery charge level and therefore extends the range of the electric motor. BMW says that to reduce fuel consumption, REx also features such functions as Automatic Start-Stop and other intelligent operating strategies.

The i3 is the smallest BMW model measuring 3,845mm long, 1,537mm wide and 2,011mm tall while riding on 2,570mm long wheelbase. It comes with four seats, wide-opening opposing “coach” doors, a rear boot capacity of around 200 liters and an additional smaller compartment in the front.

The slightly futuristic design of the exterior that shares many common styling cues with the i8 is expected to remain fairly unchanged on the production model. The interior, on the other hand, is purely conceptual and will most likely be redesigned for the showroom i3.

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