SiCycle - Recycling of end-of-life photovoltaic modules

Motivation

Since the year 2000 an increased number of photovoltaic modules have been installed in Germany and worldwide to generate renewable energies. Their typical lifetime ranges from 20 to 25 years, thus the amount of solar panels that reach their end of life will increase substantially within the next years. Until now, only limited recycling methods are available that often focus only on the recovery of the incorporated precious metals, e.g. silver. The additional recycling of the high-purity silicon would avoid the energy-intensive production of the semiconductor and therefore, pose a more economic and sustainable solution.

Brief project description

The project SiCycle utilises electrochemical methods to recycle end-of-life solar panels. For this purpose, the metals used as coatings and electrical contacts of the silicon wafer are dissolved by strongly oxidising peracids that are electrochemically generated at boron doped diamond electrodes. The high reactivity of the peracids enables the dissolution of precious metals. Simultaneously the diluted metal ions can be plated on the cathode and the acid is also regenerated. By this means, not only metals and acid can be recovered but also the undamaged silicon wafer can be recycled for the production of new photovoltaic modules. Hence, the purity of the obtained wafers as well as their photophysical properties are an important aspect of the project SiCycle and are going to be investigated.

Das IGF-Vorhaben Nr. IGF 20966 BG der Forschungsvereinigung DECHEMA e.V., Theodor-Heuss-Allee 25, 60486 Frankfurt am Main wurde über die AiF im Rahmen des Programms zur Förderung der industriellen Gemeinschaftsforschung (IGF) vom Bundesministerium für Wirtschaft und Klimaschutz aufgrund eines Beschlusses des Deutschen Bundestages gefördert.