Audi partners with Alta Devices on thin-film solar cells in panoramic glass roofs; first prototype this year
Audi and Alta Devices, a wholly-owned US subsidiary of the Chinese solar-cell specialist Hanergy, have signed a Memorandum of Understanding on Strategic Cooperation in thin film solar cell technology. Through this cooperation, the partners aim to generate solar energy to increase the range of electric vehicles. The first prototype is to be built by the end of 2017.
As the first step in the joint Audi/Hanergy thin film solar cell research and development project, the partners will integrate Alta Devices’ GaAs thin-film solar cells into a panoramic glass roof. The system will extend EV range by feeding solar energy into the internal vehicle electrical system—supporting air conditioning and other electrical appliances.
In the long term, by leveraging the technologies from both sides, the two parties plan to gradually transition to utilize thin film solar technology to feed solar energy into the drivetrain battery to provide additional primary power for vehicles.
The project will not only contribute to Audi’s vision of emission-free mobility, but also advance the application of thin-film solar technology for global primary energy generation. The two sides plan to jointly present an Audi vehicle prototype featuring an integrated prototype solar roof solution by the end of 2017.
The range of electric cars plays a decisive role for our customers. Together with Hanergy, we plan to install innovative solar technology in our electric cars that will extend their range and is also sustainable.—Audi Board of Management Member for Procurement Dr. Bernd Martens
Alta Devices produces the thinnest, lightest, and most flexible solar technology on the market: 110 µm thick, less than 200 mg, and capable of bending around a 40 mm cylinder. This form factor makes for easy integration into curved glass automotive roofs, and provides the most power possible in every type of lighting.
This partnership with Audi is Alta Devices’ first cooperation with a high-end auto brand. By combining Alta’s continuing breakthroughs in solar technology and Audi’s drive toward a sustainable mobility of the future, we will shape the solar car of the future.—Dr. Ding Jian, senior Vice President of Hanergy Thin Film Power Group Limited, CEO of Alta Devices, Inc. and co-leader of the Audi/Hanergy Thin Film Solar Cell Research and Development Project
Alta Devices grows a thin layer of GaAs on top of a single crystal GaAs wafer using a high throughput metalorganic chemical vapor deposition (MOCVD) process. It then removes this thin layer via an epitaxial lift-off (ELO) process which leaves a thin, flexible, and lightweight solar cell. Alta Devices started manufacturing and selling its third generation (Gen3) product in 2015. In 2017, it began rolling out the fourth generation (Gen4) product line.
Alta Devices’ technology holds single and dual junction solar efficiency records at 28.8% and 31.6% respectively. It achieves its record-breaking efficiencies through the observed phenomenon called “Photon Recycling”. In this process photons bounce off the back of the solar cell which allows them to be recaptured by the material and converted to electricity. Thus, more energy is captured where it would have been lost using traditional solar technology.
Gen4 represents a 30% reduction in mass resulting in an areal density of 170 g/m2 unencapsulated.