Large-scale, low-cost, and low-pollution separation of end-of-life silicon photovoltaic modules via a combined mechanical peeling and pyrolysis strategy

Developing an eco-friendly route for resource recovery from end-of-life (EOL) crystalline silicon photovoltaic (PV) modules is in high demand. Herein, an automated pilot-scale disassembly line was constructed to mechanically separate backsheets, glass, and ethylene-vinyl acetate (EVA) encapsulant with embedded silicon cells and solder ribbons from EOL PV modules. This prevents backsheets and glass from entering subsequent pyrolysis, inhibits fluorinated gas generation, and reduces energy consumption. The thermal behavior of EVA was analyzed by TG-DSC in air. Subsequently, approximately 2 kg of peeled EVA encapsulant was pyrolyzed in a pilot-scale furnace under different airflow rates to achieve complete removal of the encapsulant, yielding clean and bright crushed silicon cells and solder ribbons. Scanning electron microscope and energy-dispersive X-ray spectroscopy analyses show that airflow rate significantly impacts residual carbon content on silicon cell surfaces; surface carbon content drops from 18.59 wt% to 4.92 wt% when airflow rate increases from 10 to 40 L/min. The results verify that the integrated mechanical peeling-pyrolysis process is promising for large-scale green recycling of EOL PV modules.