A Tesla model S car with an electric vehicle charging station is displayed during a media preview day at the Frankfurt Motor Show (IAA) September 10, 2013. [Photo/Agencies]?

Electric carmaker Tesla Motors?and rail operator Deutsche Bahn opened four new charging stations along key autobahn routes on Tuesday in an effort to make electric cars viable for long-distance commuting in Germany.

Tesla's efforts to build out a network of so-called "supercharger" stations, aims to broaden the appeal of electric cars which have failed to gain widespread acceptance in Germany because of concerns about range and a lack of charging stations that allow for a fast battery top-up.

Rival carmakers such as BMW, which recently launched the i3 electric vehicle, and Daimler?which offers an electric version of its Smart car, are marketing these vehicles as "city cars" suitable mainly for short distances.

Tesla says its Model S has a range of 500 kilometres, but a lack of a charging infrastructure has limited its appeal.

On Tuesday Tesla and DB Energie, a unit of Deutsche Bahn which provides electricity for Germany's rail network, said they had built charging stations with 120 kilowatts of direct current power, allowing drivers to replenish half a battery charge in about 20 minutes, making long-distance commuting more viable.

Tesla and DB Energie opened supercharger stations in Wilnsdorf, Bad Rappenau, Aichstetten and Jettingen, enabling Tesla drivers to travel between the cities of Munich, Stuttgart, Frankfurt am Main, and Cologne.

By March 2014 Tesla aims to have a charging network that allows Tesla drivers to reach destinations in half of Germany, a spokeswoman for the company said.

Tesla now has 14 supercharger stations across Europe. These offer Tesla drivers six to eight spaces where clients can get an 80 percent charge of their car's battery in about 30 minutes.

DB Energie is also working together Deutsche Bahn's own car-sharing business Flinkster to establish charging stations for its fleet of 450 electric vehicles.