Femtosecond Laser Welding Revolutionizes Solar Cell Recycling

Researchers in the United States have made a groundbreaking discovery in the field of solar panel technology by utilizing a femtosecond laser to create glass-to-glass welds. This innovative approach aims to simplify the recycling process of solar panels, addressing a key challenge in the industry.

The proof-of-concept study conducted at the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) has demonstrated that using a femtosecond laser for welding could eliminate the need for plastic polymer sheets that are currently integrated into solar modules. These polymer sheets have been a major obstacle in the recycling process, making it more complex and less efficient.

At the end of their lifespan, solar modules produced with the laser welds can be easily dismantled, allowing for the glass and metal wires within the solar cells to be recycled with ease. Moreover, the silicon components can be repurposed, contributing to a more sustainable approach to solar panel disposal.

David Young, a senior scientist at NREL, highlighted the significance of this advancement, stating, “Most recyclers will confirm that the polymers are the main issue in terms of inhibiting the process of recycling.” By eliminating the polymers through femtosecond laser welding, the recycling of solar panels can be streamlined and made more environmentally friendly.

The femtosecond laser technology, specifically the one used by Trumpf, operates by emitting a short pulse of infrared light that fuses the glass components together, creating a durable and airtight seal. This welding technique is versatile and can be applied to various types of solar technologies, including silicon, perovskites, and cadmium telluride.

Solar modules are traditionally constructed with semiconductors sandwiched between glass layers and polymer sheets. With the new glass-to-glass welding method, the need for polymers is eliminated, resulting in modules that are more rigid and durable. Through proper mounting and modifications to the glass features, welded modules can pass stringent static load testing requirements.

NREL’s research marks a significant milestone in the solar energy industry, as it is the first to successfully implement femtosecond laser welding for glass/glass modules. Previous attempts using nanosecond lasers and glass frit fillers were deemed too brittle for outdoor module applications, making the femtosecond laser welds a game-changer in terms of strength and cost-effectiveness.

The research paper titled “Towards Polymer-Free, Femtosecond Laser-Welded Glass/Glass Solar Modules” has been published in the IEEE Journal of Photovoltaics, shedding light on the potential of this innovative technology to revolutionize solar panel manufacturing and recycling processes.

For more information, visit www.nrel.gov.