Versatility assessment of supercritical CO2 delamination for photovoltaic modules with ethylene-vinyl acetate, polyolefin or ethylene methacrylic acid ionomer as encapsulating polymer

The volume of end-of-life photovoltaic panels to be managed will increase considerably over the next decade. In the context of an environmentally friendly circular economy, it is becoming more than necessary to develop efficient recycling processes. In this context, a delamination process using supercritical CO2 was studied for the recycling of end-of-life photovoltaic modules. The process studied in this work consists of a CO2 absorption phase within the encapsulating polymer at a pressure level followed by a rapid depressurization leading to the foaming of the polymer. This foaming phenomenon leads to a loss of adhesion at the interfaces of the foamed polymer. Using a systematic experimental protocol, the minimum effective CO2 temperature and pressure are determined for three various encapsulating polymers: an ethylene-vinyl acetate, a polyolefin and an ethylene methacrylic acid ionomer. Based on this parametric optimization, the levels of separation induced by SC-CO2 foaming at the interfaces of these encapsulating polymers in photovoltaic modules are compared. SC-CO2 treatment therefore seems promising for the delamination of first generation photovoltaic modules and future generations of high efficiency perovskite-based photovoltaic modules containing ionomers. However, the results for the polyolefin indicate that SC-CO2 treatment is less effective when the encapsulating polymers do not containing CO2-philic groups.