• Miettunen, Kati
• Garg, Neha
• Santasalo-Aarnio, Annukka
• Jech, Simon

Abstract

Closed loop material recycling is essential for achieving sustainable photovoltaics. Enabling recovery of the solar panel materials and components, especially high purity silicon and solar grade glass, will reduce the need of primary materials. However, the encapsulation of silicon solar panels proved to be a great obstacle in successful high value recycling. Until now a variety of experimental separation methods has been proposed with various outcomes. The methods include thermal, chemical, or mechanical separation of the cells, glass and the encapsulant. In this study incineration, pyrolysis, and ultrasound assisted dissolution (UDT) of the encapsulant are investigated in laboratory scale experiments to compare the different methods. Electron Microscopy (SEM) coupled with Energy Dispersive X-ray Spectroscopy (EDS) is utilized for the analysis of possible contaminants on cell surfaces. We show that each method enables recovery of glass and solar cells, UDT further allows recovery of the back sheet. However, we still found carbon residues on cells after each of the method. The amount of the residues varies and so does treatment time, system complexity and possible emissions generated. We propose that a holistic view of the recycling process is needed when choosing the separation method.

Topics

• pyrolysis
• impedance spectroscopy
• surface
• Carbon
• scanning electron microscopy
• experiment
• glass
• glass
• Silicon
• Energy-dispersive X-ray spectroscopy