French scientists examined the effectiveness of various encapsulant supplies, used to laminate photo voltaic cells into modules, in defending the cells and different parts from harm brought on by ultraviolet ( UV) mild. Their findings present that encapsulants with components particularly designed to soak up UV mild are inclined to yellow over time, contributing to a wide range of efficiency issues.
The lamination and encapsulant supplies play a key function in defending the within of the PV modules from warmth, chilly, mud, moisture and, considerably mockingly, from the sunshine they’re constructed to soak up. Ultraviolet mild is a explanation for many sorts of degradation and lack of efficiency noticed within the subject, and is prone to be an issue within the newest cell applied sciences.
For the encapsulant materials itself, yellowing throughout lengthy intervals of publicity to mild is a typical drawback that may trigger a lack of efficiency in itself, and likewise scale back the extent of safety in opposition to different degradation. And that is the main target of a bunch of scientists led by France’s Nationwide Photo voltaic Vitality Institute (INES), a division of the French Various Energies and Atomic Vitality Fee (CEA), which is conducting speedy assessments of the modules constructed with completely different encapsulation supplies. .
The group produced single-cell modules, utilizing heterojunction photo voltaic cells laminated at 160 levels with 5 completely different commercially out there PV encapsulant supplies – two based mostly on ethylene vinyl acetate (EVA) and three based mostly on polyolefins ( POE). These modules have been illuminated for 4,200 hours, and the samples have been additionally examined for as much as 1,300 hours beneath ultraviolet radiation and excessive temperatures, to check the results of UV mild alone.
The experiments are described in full within the paper “Photo voltaic cell UV-induced degradation or module discolouration: Between the satan and the deep yellow,” revealed in Advances in Photovoltaics. After the check, the modules are inspected visually and measured for fluorescence and present/voltage efficiency.
The outcomes confirmed that the EVA encapsulant was essentially the most affected, and two of the POE samples additionally confirmed slight yellowing. Notably, the three samples with yellowing have been these with components designed to soak up UV mild. After 4,200 hours of testing, the EVA module was proven to have misplaced 4.2% of its preliminary efficiency.
The examine concluded that UV-absorbing components are inclined to degrade, affecting PV module efficiency over time. Nonetheless, the researchers notice that the safety they supply in opposition to different degradation mechanisms is prone to nonetheless justify their use – so long as the photo voltaic cells they shield stay weak to UV degradation. “The destruction of UV absorbers is a matter that impacts the integrity of the whole PV module and may result in speedy delamination, and different vital sorts of harm,” the researchers defined. “There’s a problem to search out new methods to strengthen the photoprotection of the machine, particularly for the harshest environments, similar to these in deserts.”
Relating to options to this problem, they counsel attempting mineral-based as an alternative of natural UV absorber supplies, and likewise notice that quantum dots will ultimately turn out to be an alternate resolution, though they’re nonetheless out there. within the early phases of analysis. Lastly, they counsel investigating UV-absorbing glass, changing the necessity for encapsulant components.
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