Flexible solar cells from the roll

A Fraunhofer research team is working on an innovative manufacturing process for solar modules.

Large-area conducting path patterns for photovoltaics

In the LEO project (platform technology for the resource-saving production of conductor paths on large surfaces equipped with electronics), Fraunhofer ISE and Fraunhofer EMFT are bundling their expertise in fine line metallization and roll-to-roll processing as well as thin-chip integration in foils. 

 Im Projekt LEO entstehen kostengünstige Kupferleiterbahnstrukturen für die Anwendung in großflächigen elektronischen Bauteilen wie z.B. Solarmodule. ©Fraunhofer ISE
© Fraunhofer ISE
In the LEO project, cost-effective copper conducting path structures are created for use in large-area electronic components such as solar modules.

In order to demonstrate that the novel process is a sustainable and cost-effective alternative to proven manufacturing processes in the PCB industry, the research team focuses on the transfer of the individual processes substrate manufacturing, patterning, electroplating and etching to a roll-to-roll format. With the production of the first conductor path samples on the roll-to-roll pilot line at the Fraunhofer EMFT, the compatibility of the Leo technology with continuous production processes could be shown. 



The technology can be used, for example, to produce flexible and transparent organic solar cells in a roll-to-roll process which can be integrated into all possible designs. During the project activities, the team has already been able to produce 20 µm wide, galvanically reinforced conductor paths on film substrates for flexible organic solar cells. 

Roll-to-roll: An old principle in a new interpretation

The roll-to-roll process for the production of printed electronics has a long-established role model: newspaper printing. In this process, unprinted carrier material is winded up on a roll, with an empty roll on the opposite side. The individual printing processes run one after the other in between, with the carrier material being spooled onto the empty roll on the other side of the press. In the laboratories of Fraunhofer EMFT, researchers use this method to produce ultra-thin electronic components on film. These electronic foils are used, for example, in medical technology as sensors close to the body, in robotics and also in solar cells. The so-called "roll-to-roll" process is particularly efficient for such large-area components. 

© Fraunofer EMFT / Bernd Müller
Kontinuierliche Rolle-zu-Rolle-Verarbeitung elektronischer Folien. Continuous roll-to-roll-processing of electronic foils.