Researchers in Spain investigated effective separation from PV glass inputs with a focus on smeling behavior and resistance to the hot MES method of delamination. The results indicated that thermoplastic polyolefine -linksulating agents could be removed the easiest from the PV glass.
Spanish researchers from the Public University of Navarra (UPNA) and the National Renewable Energy Center (Cener) have investigated the melting points of three conventional encapsulating materials in a research project for recycling the PV panel at the end of life. They also determined the convenience to remove them using a hot-knife Delamination method.
A better understanding of incoming melting behavior under recycling conditions is “essential” to optimize delamination processes to improve the efficiency of recycling strategies, according to the researchers in a study that focused on a hot-MES method. The goal was to determine at which point often used encapsulant -materials “malleable and easier to separate” from PV module glass.
“The primary obstacle in recycling photovoltaic modules at the end of life is the Inkapsulant, which is strongly attached to and protects the solar cells,” said the corresponding author of the Asier Murillo study PV -Magazine. “We have therefore considered it essential to investigate the behavior of different polymere encapsulants during the delamination process under different temperature conditions.”
By doing this, the researchers were able to identify which encapsulating types are easier to destamine and determine the temperature ranges in which their attachment strength starts to fall.
“These findings offer valuable insights into optimizing delamination strategies, improving process efficiency and ultimately facilitating more effective PV module recycling,” Murillo explained.
In the study, differential scanningcalorimetry (DSC) was used to determine the melting temperatures of Inkapsulantia made of ethylene-vinylacetate (EVA), polyolefine-elastomer (POE) and thermoplastic polyolefin (TPO), with the suction method.
“In particular, we used a offense approach that is comparable to the hot-MES technology developed by the Japanese company NPC Incorporated,” said Murillo.
The team manufactured small PV modules with one cells to evaluate and compare the Delamination power of the different Encapsulants under selected temperatures. The Delamination tests were performed at different temperatures using a knife to separate the glass from the remaining layers. The sample modules were based on Passivated Emitter Rear contact (PERC) Monocrystalline silicon cells with an active surface of 26.96 cm. The samples had polyvinyl fluoride (PVF) Tedlar back shoes
The results showed that TPO showed the lowest delamination strength, followed by Eva and Poe, where the last two needed comparable forces as soon as their melting ranges were exceeded.
“Moreover, the results indicate that excessive heating does not significantly improve the delamination process,” the scientists said.
They also made thermally characterized pellets made of the three encapsulating materials at temperatures ranging from a maximum of 200 ° C to determine the smeling behavior.
The research has been documented in “Impact of melting range on delamination process and recycling potential of photovoltaic encapsulants“Published in Solar energy materials and solar cells.
Assessment of the quality of the hot knife separation process, the researchers noted that the encapsulated solar cell with its electrical contacts and the rear shoes were “effectively restored” and the glass “remained structurally intact with small incoming residues.”
They concluded that the results indicate the efficiency of the hot-MES technology when “making the complete recovery and recycling” of photovoltaic glass. In comparison with alternative methods such as pyrolysis or chemical treatments, which also offer high quality results, this method requires lower energy input and not dangerous chemicals. They concluded that the “Hot-MES process presents a more practical, energy-efficient and ecological sustainable solution for PV module management.”
The research team continues its recycling-related delamination research, this time this time works with PV-mini modules that are subject to various stress conditions, such as exposure to moisture and UV, according to Murillo.
It also contributes to the development of a PV recyclability index in collaboration with the European Commission and other partners. Moreover, it is planning to present the latest results of his research into nanog-structured glass and solar cells that do not require incoming in encapsulants, on EU PVSEC 2025 in Bilbao.
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