An Efficient Separation Method for a Photovoltaic Modules Backsheet Based on Swelling and Gas Expansion at Low Temperature

Scientific and technological advancement demands substantial energy input, driving the rapid expansion of clean energy sources like photovoltaics due to their environmental advantages over polluting fossil fuels. Consequently, the growing installed capacity of photovoltaic (PV) modules raises concerns regarding the environmental impact of end-of-life modules. PV modules contain valuable components, and improper disposal represents significant resource waste and environmental risk. Projections estimate that PV module waste will reach 8 million tonnes by 2030 and 78 million tonnes by 2050. Although various recycling and disposal methods exist, inefficiencies and inadequate environmental protection persist. This study presents a low-temperature solvent separation system utilizing a cooling bath, enabling rapid module separation through the synergistic effects of low temperature, solvent swelling, and gas expansion. The system achieves backsheet stripping within 30 s at temperatures between −50 and −30 °C, significantly enhancing the separation efficiency. Meanwhile, cryogenic and thermal treatment (80 °C oven for 2 h) can be used together to reduce the cryogenic soak time required for complete separation, further improving the separation efficiency. On this basis, in combination with the PV module production process, the layers in the PV module, especially the separation layer and the backsheet composition, were determined. This method offers an environmentally sustainable and highly efficient approach with considerable potential for widespread application in PV module recycling.