Small electric cars are currently making a big splash within the VW Group. Now Audi is jumping on the bandwagon too and expanding its range downwards – with a model range that has already caused quite a stir. Audi AG/dpaAudi has launched what it bills as the 'most efficient model in its history' with the A2 e-tron.The new electric model revives the iconic A2 nameplate, first used in the innovative city car launched in 2000. Like its predecessor, the new e-tron places a heavy focus on efficiency and cutting-edge technology. It's why the A2 e-tron has a low drag coefficient of just 0.24, the lowest of any car in Audi's line-up.Available with three battery sizes – 52, 61 and 84kWh – the new A2 e-tron gets a claimed range of up to 646 km, while a charging speed of up to 183kW will allow for a 10 to 80% charge in under 30 minutes.AdvertisementAdvertisementAll versions use a single rear-mounted electric motor, though there will be power outputs ranging from 168 bhp to 322 bhp.Inside, the A2 e-tron has a 12.8-inch curved infotainment system, sitting alongside an 11.9-inch virtual cockpit display ahead of the driver. Audi says that a large panoramic sunroof can be added as an optional extra, too.The A2 e-tron will also get bidirectional charging as standard, which allows the car to both receive energy from the plug and send it back to the grid in certain cases. Vehicle-to-load also allows the car's on-board energy supply to be used to power external devices.The A2 e-tron is also the first car to get Fidlock's magnetic fastening system which allows owners to 'click' accessories such as cupholders or charging bags to various anchor points.AdvertisementAdvertisementAll versions will get a broad range of assistance systems, including emergency brake assist which can help in the event of an imminent collision, while a dedicated emergency assist feature can initiate an emergency stop if it detects that the driver is unresponsive. Set to go on sale next month, the new A2 e-tron is priced from €38,200 in its home market of Europe. This is a good 20% less than the Q4 e-tron, which until now has been the entry-level model in Audi's electric range.