A group of US researchers has developed a way to make solar panels easier to recycle. The innovation enables glass-to-glass welds that eliminate the need for plastic polymer sheets.
The US Department of Energy’s National Renewable Energy Laboratory (NREL) is pioneering a laser method to produce more sustainable solar panels. It uses an extremely short pulse (femtosecond) of infrared light that melts the glass together to form a strong, hermetic seal.
The welding technique can be used on any solar technology: silicon, perovskite or cadmium telluride because the heat of the weld is confined to a few millimetres of the laser focus.
‘As long as the glass doesn’t break, the weld is not going to break,’ reports NREL scientist David Young. At end-of-life stage, modules with this type of laser welding can be shattered to enable disassembly. ‘The glass and metal wires running through the solar cells can be easily recycled, and the silicon can be reused.’
Young says most recyclers confirm that polymers are ‘the main issue’ when recycling solar panels. That’s because semiconductors are typically sandwiched between two sheets of glass laminated together with polymer sheets.
‘Our paper showed that with proper mounting and a modification to the embossed features of the rolled glass, a welded module can be made stiff enough to pass static load testing,’ Young notes.
NREL’s research is the first to use a femtosecond laser in a module. The method also offers improved thermal properties and superior strength at a compelling cost.
Young asserts that the research is ‘definitely high risk, high reward.’ He suggests extending the life of solar modules to at least 50 years for the most sustainable outcome.
The NREL work was supported by researchers at Trumpf and the Durable Module Materials Consortium.
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