FRANKFURT MOTOR SHOW: Audi e-tron quattro concept

It's official: Audi has confirmed it will release its first mass-production all-electric car in 2018 – a large SUV with a driving range of more than 500km, as it first indicated in March.

To prove it, the German car-maker has released the five official sketches of the car that will preview it at next month's Frankfurt motor show -- the Audi e-tron quattro concept – confirming that the leaked images of the ground-breaking model seen late last month were in fact the real deal.

Audi says the four-seat e-tron quattro concept is "designed from the ground up as an electric car", but the production version is expected to be badged as the Q6 e-tron (indeed Audi has now confirmed "its length is between that of the Audi Q5 and the Q7).

Based on the recently launched Q7’s MLB Evo platform, the zero-emissions SUV will be joined a number of other engine variants to compete with the large German coupe-crossovers like the BMW X6 and Mercedes-Benz GLE Coupe.

Along with next year's pint-size Q1 and the Q8 flagship due by 2019, the Q6 will help double the size of Audi's existing SUV range (Q3, Q5 and Q7) within four years and grow Audi’s model line-up from today’s 52 vehicles to 60 by 2020, during which time it will invest €24 billion on R&D.

Audi last week revealed the e-SUV will employ next-gen battery technology from South Korea's LG Chem and Sumsung SDI, in the form of a large lithium-ion battery positioned between the axles and below the passenger compartment, delivering a low centre of gravity and balanced axle load distribution.

The Q6 e-tron will lift its powertrain from the R8 e-tron supercar, but instead of two rear-mounted motors the Q6 will benefit from an additional (third) motor encased within its gearbox generating, increasing its performance outputs to a combined total of as much as 375kW/700Nm.

With expected widespread use of lightweight composites like carbon-fibre, the direct rival for Tesla's upcoming Model X SUV is expected to hit 100km/h in less than four seconds and a top speed limited to 250km/h.

Tonight Audi said the concept will set a new aerodynamic record for SUVs at 0.25Cd, thanks in part to the low-slung coupe-like roofline, "movable aerodynamic elements at the front, on the sides and at the rear" and a completely enclosed underbody.

As well as a state-of-the-art powertrain the next-generation Q6 e-tron is expected to have a fully autonomous driving feature allowing occupants to enjoy the big Audi’s next-generation infotainment system.

These latest design sketches reveal the concept will feature OLED-based operating and display systems on the inside, and headlights with e-tron light signatures up front.