Using Lasers To Extend Solar Panel Life To 50 Years

Recently, the National Renewable Energy Laboratory (NREL), part of the U.S. Department of Energy, made a revolutionary breakthrough when they developed a proof-of-concept methodology designed to completely remove polymers from the manufacture of solar panels for more efficient and environmentally friendly recycling.
Solar panels have long been lauded for their recyclability. However, the thin plastic layers used in the manufacturing process present challenges that hinder the efficient recycling of valuable materials such as silicon and silver.
To address this challenge, NREL's research team has taken a different approach and come up with an innovative solution to implement glass-to-glass welding directly in solar cells.
The core of this solution lies in the utilization of infrared femtosecond laser technology. By precisely controlling the laser pulse, the energy is focused on a specific area of the solar panel in a very short period of time, creating a robust glass-to-glass weld. It is worth mentioning that femtosecond laser technology has already been widely used in the field of medical eye surgery, such as cataract surgery, and its safety and reliability have been fully verified.
With laser welding, the need for plastic laminates in solar panels is completely eliminated, thus greatly simplifying the recycling process. At the end of the panel's service life, these modules made by laser welding can be easily broken down, the glass and metal wires in them can be recycled without any problems, and the silicon material can be reused.
David Young, a senior scientist in the Efficient Crystalline Photovoltaics Group in NREL's Department of Chemistry and Nanoscience, said, "There is a general consensus among most recyclers that polymers are the main issue that hinders the recycling process. The advent of our technology certainly opens up a whole new set of possibilities for solar panel recycling."
The research has been published in the IEEE Journal of Photovoltaics. The research team points out that the laser welding technology has a wide range of applicability, not only for silicon materials, but also with a variety of materials such as chalcogenide and cadmium telluride. Due to the highly focused nature of the laser, the heat generated is limited to a very small range and does not cause damage to the battery material. At the same time, the strength of the welds inside the glass is comparable to that of the glass itself, ensuring the long-term stability and durability of the module.
Young further explains, "As long as the glass itself doesn't break, the welds will be fine. Moreover, the hardness of the welded module is significantly improved due to the absence of polymer between the glass pieces. Our research shows that with proper installation and modification of the embossed features of the rolled glass, the welded module can become hard enough to meet the requirements of static load testing."
In the past, researchers have attempted edge sealing using nanosecond lasers and glass frit fillers, but the results have not been favorable. The brittle nature of the welds made them unsuitable for outdoor module designs. In contrast, the femtosecond laser welding technology developed by NREL achieves superior sealing strength at a fraction of the cost, providing a strong technology for solar panel recycling.
This research is supported by the Durable Module Materials Alliance, which is dedicated to extending the life of solar panels to 50 years and beyond. With NREL's innovative laser technology, we can expect to realize more efficient and environmentally friendly solar panel recycling in the future, contributing to the sustainable development of renewable energy.