Chemical and mechanical interfacial degradation in bifacial glass/glass and glass/transparent backsheet photovoltaic modules. (29th June 2022)

• Record Type: Journal Article
• Authors: Spinella, Laura; Uličná, Soňa; Sinha, Archana; Sulas‐Kern, Dana B.; Owen‐Bellini, Michael; Johnston, Steve; Schelhas, Laura T.
• Is Part Of: Progress in photovoltaics. Volume 30:Number 12(2022)
• Page Start: 1423
• Page End: 1432
• Publication Date: 2022-06-29
• Subjects: adhesion -- bifacial -- DuraMAT -- EVA -- glass–glass -- ion migration -- POE; Solar cells -- Periodicals; Photovoltaic cells -- Periodicals; Solar power plants -- Periodicals; 621.31245
• DOI: 10.1002/pip.3602
• Languages: English
• ISSNs: 1062-7995

Abstract

Abstract: Glass/glass (G/G) photovoltaic modules are quickly rising in popularity, but the durability of modern G/G packaging has not yet been established. In this work, we examine the interfacial degradation modes in G/G and glass/transparent backsheet modules under damp heat (DH) with and without system bias voltage, comparing emerging polyolefin elastomer (POE) and industry‐standard poly(ethylene‐co‐vinyl acetate) (EVA) encapsulants. We investigate the transport of ionic species at cell/encapsulant interfaces, demonstrating that POE limits both sodium and silver ion migration compared with EVA. Changes to the chemical structures of the encapsulants at the cell/encapsulant interfaces demonstrate that both POE and EVA are more susceptible to degradation in modules with a transparent backsheet than in the G/G configuration. Adhesion testing reveals that POE and EVA have comparable critical debond energies after the DH exposures regardless of system bias polarity. The results of this study indicate that the interfacial degradation mechanisms of G/G appear to be similar to those of conventional glass/backsheet modules. For emerging materials, our results demonstrate that POE offers advantages over EVA but that transparent backsheets may accelerate encapsulant degradation due to increased moisture ingress when compared with the G/G structure. Abstract : G/G modules with POE were found to be more durable than those with EVA or transparent backsheet. The high resistivity POE inhibits sodium migration through the interfaces under negative and silver migration under positive bias, decreasing risk of PIDs and transmittance loss as compared to EVA. Interfacial adhesion strength reduced for both EVA and POE encapsulants resulting in similar risks of delamination under the damp heat conditions.