Waste can now be reborn! German scientists have developed a renewable PERC solar cell made with 100% discarded modules, and the result is a conversion efficiency of 19.7%.
Solar installed capacity is increasing each year as carbon reduction and green energy become global doctrines, and the global installed capacity had surpassed 700GW in 2020, though solar panels have a fixed lifespan, and are prone to damages from natural disasters and other incidents during service that would require replacement of modules. Hence, it is crucial to start thinking about the disposal of solar panels, or else they will become a burden at the end.
In Germany, roughly 10K tons of discarded solar panels are thrown into recycle plants each year, and the figure will surge to hundreds of thousands by 2029. As a result, the Center for Silicon Photovoltaics of Fraunhofer, Fraunhofer ISE, and German solar recycling company Reiling GmbH & Co. KG have joined hands in the hopes of developing a technology that recycles and reuses any solar panels, providing a second chance for discarded modules.
（Source：Fraunhofer ISE）
Fraunhofer pointed out that the team first separated 0.1-1mm of battery fragments from glass and plastic through various sorting processes, before removing backside contact, silver contact, anti-reflection coating, and emitter using wet etching.
The German research team also managed to generate a conversion efficiency of 19.7% for the PERC cell made with recycled silicon, which although is lower than the efficiency of 22.2% from existing PERC solar cells, generates a much higher level of power compared to discarded solar cells.
Wet etching is primarily applied on the processing of mono and mono-like ingots before they are turned into wafers. German scientists commented that the new cell is completely made with recycled silicon, with no commercial pure silicon added throughout the production process. However, the secret behind the technology cannot be revealed, and Peter Dold, Project Manager of Fraunhofer CSP, commented that the technical details are to be kept as a secret.
(Cover photo source: shutterstock)