Research Progress on Recycling Technologies for Retired Photovoltaic Modules
The rapid expansion of photovoltaic (PV) installations and the impending retirement of early-stage modules have made the recycling of end-of-life PV modules an urgent issue. This review systematically examines the types and structures of retired PV modules, with a focus on crystalline silicon (c-Si) and thin-film technologies. It critically evaluates the principles, processes, and pros and cons of physical, chemical, pyrolysis, biological, combined, and emerging methods for recovering c-Si modules. The current status of silicon, metal, and valuable component recovery processes is summarized. For thin-film modules, the core technologies for recovering valuable components via pyrometallurgical, hydrometallurgical, biological, and novel approaches are analyzed in depth. Results indicate that conventional methods (physical, chemical, pyrolysis) remain dominant but suffer from high energy consumption, pollution, and chemical usage. Emerging technologies such as biological and green leaching are identified as key research directions, though they face challenges of low technical maturity and high costs. Finally, policy orientations and existing challenges are discussed, and future development directions are proposed, providing significant guidance for the sustainable and large-scale green development of the PV industry.