Researchers on the University of New South Wales declare to have recognized three TOPCon panel failure varieties that aren’t current in PERC merchandise. They clarify that these failures can happen if the modules are uncovered to excessive humidity and contaminants earlier than encapsulation.
Scientists from the University of New South Wales (UNSW) in Australia declare to have recognized three new varieties of TOPCon photo voltaic module failures which have by no means been seen in PERC panels.
“The outcomes actually shocked us,” the lead writer of the analysis, Bram Hoex, mentioned pv journal. “We anticipate polyolefin elastomer (POE) to usually carry out nicely, however we acknowledge that some POEs carry out poorly. This might be as a result of numerous components utilized in POE reacting with the soldering flux and the metallization leading to contact breakdown.
The scientists mentioned their work was initially supposed to look at the impression of payments of supplies (BOM) on the reliability of each commercially out there PERC and TOPCon photo voltaic cells. They decided that each one modules had been encapsulated in a pilot line inside an unspecified industrial facility.
“These processes embody soldering to attach the ribbon and tabbing wires to the busbars and laminating to hitch the BOM forming modules,” they defined, noting that each one the panels underwent a humid warmth (DH) check at 85 C and 85% humidity for as much as 1,000 h. They mentioned that each one BOM elements, akin to glass, polymer backsheet, ethylene vinyl acetate (EVA), and POE, are bought from numerous producers world wide and thought of for top quantity manufacturing. The names of the suppliers weren’t disclosed, resulting from “confidentiality considerations.”
The workforce carried out current-voltage (IV) measurements utilizing the Eternalsun Spire module flash tester and obtained Line-scan open circuit photoluminescence (PL).LS) and electroluminescence (ELLS) pictures by the BTi-M1 luminescence line-scan system earlier than and after the DH check. “ELLS Image ratios are obtained by dividing by ELLS pictures taken earlier than and after 1000 hours of DH testing utilizing Lumitools, a sophisticated picture processing software program,” it highlighted.
The collection of checks confirmed that the strategies used to encapsulate the panels with top quality (POE) and low high quality (EVA) have a “negligible” impact on the efficiency and reliability of PERC cells, with the noticed adjustments outlined as “minimal in nature.”
In distinction, the examined TOPCon cells present a better most energy loss in comparison with their PERC counterparts, with most energy values diminished from round 30% to 25 worth for modules embedded in several types of POE and from roughly 29% to 26% for panels wrapped in EVA. These losses are primarily resulting from elevated collection resistance.
“Our findings present that PERC modules present stability, with a 1-2% discount in peak energy after 1000 h of DH testing, whatever the BOM used, ” mentioned the analysis workforce. “In distinction, the TOPCon modules skilled vital degradation, with a most power discount of 4-65% relative after the identical period of the DH check.”
Through testing, scientists have recognized, particularly, three varieties of failures: A degree-local failure; a failure mode that happens on the interconnection level between the ribbon wires and busbars of the cells; and an entire failure of all the space of cells and modules.
They attributed the reason for the primary failure to the electrochemical response between moisture, cell metallization, and contaminants that will have been current within the cells earlier than encapsulation. For the second kind, they mentioned it was noticed in modules with TOPCon cells containing EVA or POE, ranging from the interconnection level after which spreading to the encompassing space of the cell after an prolonged DH check.
As for the Type-3 kind of failure, it was discovered to happen in modules with TOPCon modules encapsulated in POE, most likely resulting from an electrochemical response between cell metallization, moisture, soldering flux , and demanding parts launched.
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Academics say these outcomes present the vulnerability of TOPCon photo voltaic cells when uncovered to excessive humidity and contaminants earlier than encapsulation. “Careful consideration is required within the dealing with and number of encapsulants for TOPCon modules,” they warn.
Their findings are introduced within the research “Buyer conscious: Three new failure modes in TOPCon modules absent from PERC know-how,” lately printed in Solar Energy Materials and Solar Cells.
The identical analysis group recognized final 12 months 4 failure modes resulting from moist warmth in heterojunction photo voltaic panels with glass cores. These failures can lead to energy losses starting from 5% to 50%.
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