link to homepage

Institute of Energy and Climate Research

Navigation and service


PATOS is carried out with financial support of:



The aim of the PATOS project is a development of high efficiency (over 22%) solar cells with focus on low production costs for vehicle integration, where visual appearance is as important as the high power output.

Due to the increase in electrification modern vehicles get equipped with high capacity batteries. At the same time options to power the on-board equipment like air conditioning or warming without loss of range are examined.

Integration of solar cells directly in a roof of a car facilitates charging of the battery during parking and supports vehicle's electrical system during driving. For these applications solar modules of highest possible efficiency of above 20% are required due to limitations of available area. Furthermore visual appearance and geometrical design of these modules are of highest priority for successful marketing.

Among the available solar cell concepts the silicon heterojunction (SHJ) solar cells have very high efficiency and potential for low cost mass production. In addition the SHJ cells provide enough freedom for custom module design.

In the project the traditional technique for thin film silicon deposition – Plasma Enhanced Chemical Vapor Deposition - will be replaced by the potentially less expensive Hot Wire CVD technique.

Further cost reduction will be achieved via replacement of indium oxide with Al-doped zinc oxide for transparent contacts, use of copper instead of silver for metal contacts and increase of manufacturing flexibility as for the cell shape with aid of laser processing and electroplating.

At the next stage the optimized cells will be assembled into modules and the modules will be in turn tested for suitability for car roof integration.

Project partners:

Audi AG, VON ARDENNE GmbH, a2-solar, RENA Technologies GmbH, Forschungszentrum Jülich GmbH, Fraunhofer-Institut für Schicht- und Oberflächentechnik, Institut für Halbleitertechnik RWTH Aachen