Effectively and completely separating the waste crystalline silicon photovoltaic modules via green solvothermal strategy

Abstract

Crystalline silicon photovoltaic (PV) modules currently dominate the market due to their cost-effective and established technology. However, many of these modules are expected to be decommissioned soon. The solar cells within these modules, particularly the silver grid lines, possess considerable recycling value. Nevertheless, the precise layer-by-layer separation of laminated components has proven to be a challenging issue, with the separation and disposal of fluorinated backsheet emerging as a critical challenge in the industry. Here, we propose a solvothermal strategy to effectively separate both sides of adhesive ethylene vinyl acetate (EVA) films, and fluorinated backsheet as well as retrieve the silver grid lines. We demonstrate that immersing the laminates containing the backsheet in anhydrous ethanol at 200 °C for 15 min simultaneously separates the aluminum back electrode and the back EVA film without causing swelling. Further immersing the separated laminates in a 0.3 mol/L aqueous sodium carbonate solution at 200 °C for 120 min enables the effective separation of the silver grid lines and the front EVA film. This method proves to be highly effective and environmentally safe without using harmful organic chemicals. It offers significant advantages over traditional pyrolysis methods in reducing carbon emissions and contributes to the recovery of EVA films, which shows considerable potential to facilitate the development of waste silicon-based PV module recycling.