A novel method for layer separation of photovoltaic modules by using green reagent EGDA

Abstract

With the number of lifespan-limited photovoltaic (PV) modules rising significantly, the recycling of scrapped PV modules containing valuable and hazardous components has become a critical issue. The most valuable resources are concentrated on solar cells bonded to other layers by EVA. To adequately recover available resources and harmful components for resource reuse and environmental protection, the separation of different layers in PV modules should be achieved effectively. Among several methods for layer separation, the chemical method is a promising way due primarily to its low energy consumption. However, most separation reagents used in the chemical method are toxic, such as toluene, 1,2-dichlorobenzene, and trichloroethylene. In this study, a new method using green reagent EGDA (ethylene glycol diacetate, C6H8O4) to accomplish the layer separation was proposed. Ingredients of different layers were characterized by XRD, XRF, FTIR, Raman, and SEM/EDS to explore the resource distribution. Meanwhile, three methods separating different layers were compared—the use of 1,2-dichlorobenzene, the use of EGDA, and the direct pyrolysis. Moreover, the effects of temperature, ultrasonic field, and solid/liquid ratio on the glass peeling rate were investigated. Furthermore, compared with water, EGDA has better wettability on glass, meaning that EGDA can penetrate the glass-EVA gap more easily. Finally, the mechanism of layer separation by EGDA was explored by SEM, FTIR, and GC–MS. This process is resource-sustainable, which can be expected to be applied on a large scale.