An application of solvent and thermal treatment to recover materials from photovoltaic module encapsulated with polyolefin elastomer.

Abstract

High-quality recycling of photovoltaic (PV) modules starts with a delamination process. It aims to remove the encapsulation layer between glass and solar cells. Many studies have investigated the delamination of ethylene-vinyl acetate encapsulant, whereas the delamination of polyolefin elastomer (POE) encapsulation in solar modules remains a research gap. This study presents methods of solvent and thermal treatment for the separation of layers in a PV module encapsulated with POE polymer. Various organic compounds were tested for the solvent treatment. The results showed that most of the solvents did not separate the materials. However, with some of them, polymer swelling was achieved. Glycerol was the only solvent capable of separating glass from multi-material laminate. The separated glass does not include contaminants and is therefore suitable for the use as a secondary material. However, the solar cells remained encapsulated in the polymer, thus additional processing is needed to remove it. The time and solvent temperature for glycerol treatment were measured. The thermal treatment was conducted based on the results of thermogravimetric analyses, which determined the degradation of POE under heating conditions. Thermal treatment at 500°C for 1 hour in an air atmosphere was found to be the effective way to detach PV layers. Glass, solar cells and metal ribbons were separated without polymer contamination and are therefore suitable for further use.