Audi developing solar-cell sunroofs

Audi is working on a panoramic sunroof that will use the sun to extend the range of its future electric cars.

Developed with Alta Devices, a subsidiary of Chinese solar power specialist Hanergy, the thin-film solar-cell technology will be integrated with a panoramic glass sunroof.

Audi says the first prototype will begin testing by the end of this year and that, in future, almost the entire roof surface of its vehicles will be covered with power-generating solar cells.

However, it is yet to reveal exactly how much power they can make and says the electricity they generate will flow into the car’s electrical system to supply auxiliary systems such as air-conditioning or seat heaters, representing “a gain in efficiency that has a direct positive impact on the range of an electric vehicle”.

Audi claims the thin and flexible cells, which are made in California and could eventually feed solar power directly into an EV’s traction battery, have an efficiency of more than 25 per cent and perform very well low light and high temperatures.

“The range of electric cars plays a decisive role for our customers,” said Audi Board of Management Member for Procurement Dr. Bernd Martens.

“Together with Hanergy, we plan to install innovative solar technology in our electric cars that will extend their range and is also sustainable.

“That would be a milestone along the way to achieving sustainable, emission-free mobility.”

Toyota already has similar technology in production, offering a solar panelled roof option  for the plug-in version of the Prius hatch sold in Australia, which in some markets is known as the Prius Prime.

Charging the car when parked, Toyota claims the system boosts the car’s electric-only range by at least 10 per cent in normal conditions, potentially to around 55km at speeds of up to 135km/h.