A review on dissociation and resource utilization of decommissioned crystalline silicon photovoltaic modules

In recent years, the global photovoltaic industry has been booming, and the installed capacity of photovoltaic has climbed rapidly. The carbon emission of photovoltaic power generation is only 10% compared with that of traditional fossil fuel power generation. However, the service life of solar photovoltaic panels is only 20 to 25 years, and as the first batch of photovoltaic modules reach their life limit, the world will successively usher in the "retirement tide" of photovoltaic modules. To realize the harmless and green disposal of retired photovoltaic modules and recycle the secondary energy in photovoltaic modules is the key link of the sustainable development of photovoltaic industry. At present, the mainstream crystalline silicon photovoltaic modules are composed of photovoltaic glass, EVA (ethylene-vinyl acetate copolymer) film, crystalline silicon cell sheet and fluorine backplane. The complete photovoltaic glass and crystalline silicon cell have high economic value, so how to selectively remove EVA film and fluoride backplate is an important step in the recycling of retired photovoltaic modules. Based on this, this paper first introduces the structure and application of each part of crystalline silicon photovoltaic module. Then according to the physicochemical characteristics of each part, the advantages and disadvantages of various processes including thermal disposal, physical separation and chemical dissociation are analyzed in detail from the perspective of the integrity of photovoltaic module recovery. Existing studies have shown that the difficulties in the recovery of retired crystalline silicon photovoltaic modules are mainly in the following three aspects: the removal of EVA film with high efficiency, low pollution and low energy consumption, the harmless disposal of fluorine-containing substances in the backplane, and the removal of pyrolysis carbon residues on crystalline silicon cells. In view of the above difficulties, this paper outlooks the future development trend of recycling technology for decommissioned photovoltaic module, and puts forward some reasonable suggestions on the research and design of recycling technology for decommissioned photovoltaic module in China. This paper will provide an important technical guidance for the efficient green recycling of decommissioned photovoltaic modules.