Solvent-free ultrasonic approach for delamination of end-of-life crystalline-silicon PV modules

Abstract

Ultrasonic cavitation is widely used for cleaning and surface modifications. However, solvent-free ultrasonic applications to delaminate EVA from photovoltaic (PV) stacks and its environmental perspective remain limited in the literature. Ultrasonic delamination enabled the complete delamination of glass and front EVA and partially the release of c-Si fragments from the back EVA layer. The process achieved a delamination success rate of 82.2% by mass, suggesting that the separation mechanism of front encapsulant layer (EVA) under the applied conditions is mechanical interfacial weakening rather than bulk chemical degradation. Mechanical analysis supports that EVA exhibited the highest deformation (1.6 mm), while glass (0.57 μm) and c-Si (0.0267 μm) remained relatively unaffected due to its lower elastic modulus. These results align with previous studies on cavitation-induced surface modifications in various materials at ultrasonic frequencies. The study further highlights the life cycle assessment (LCA) of ultrasonic cavitation delamination with net CO₂ emission savings of −5.75E+00 kg CO₂ eq., the environmental impact of the lab-scale processes. The findings establish the potential of ultrasonic cavitation as a solvent-free approach for PV recycling and critical mineral sustainability.