© Fraunhofer IKTS

New photovoltaic cells developed in Germany based on textiles for integration in the transport and construction sectors.

A new photovoltaic system to cover building facades, windows and even truck trailers. This is the path that Dr Lars Rebenklau of the Fraunhofer IKTS wants to follow in order to create the new generation of photovoltaic energy. The scientist, together with his team, colleagues from Fraunhofer ENAS and various industrial partners, are working on a new line of textile solar panels, a technological solution in which traditional glass or plastic substrate is replaced by textile.

This is not a real novelty, as Rebenklau himself explains:

Today there are many methods for incorporating solar cells into coatings applied to fabrics. However, the technical difficulty of having such a product remains enormous. It may sound easy, but machines in the textile industry are designed to handle large rolls of fabric: five or six meters wide and up to 1000 meters long. And during the coating process, the fabrics must withstand temperatures of around 200 ° C. Not only that: for use in the photovoltaic field, the fabric must also meet precise fire standards, have resistance with high tensile strength and be inexpensive to produce. For the large group of researchers, a fiberglass fabric was the solution to all of these specifications.

However, to make their textile solar panels, scientists first had to find a way to accurately apply all of the thin layers that make up the cell – the bottom electrode, the photovoltaic material, and the top electrode – to the surface. uneven fiber. .of glass.

The solution, the researchers explain, was to first create a layer that would level the peaks and channels of the fabric through transfer printing, the same one used to make gummed fabrics.

All other processes have been adapted to easily integrate into standard production methods of the textile industry. For example, the two electrodes, made of electrically conductive polyester, and the photovoltaic layer are applied by the standard roll-to-roll method. The solar cells are also laminated with an extra layer of protection to make them more robust.

The team has already produced a first prototype.

This demonstrates the functionality of our textile-based solar cells. Right now they have a yield of between 0.1 and 0.3%, but the goal is to reach over 5%, which would allow the devices to be commercially viable. If all goes according to plan, according to the team, the first textile solar panels could be ready to market in about five years.