Presentation Details
| The Operation and Durability of UV-Downshifting Encapsulants for Contemporary PV Modules David Miller, Xavier Hanna, Dennice Roberts, Rachael Arnold, Jimmy Newkirk, Kent Terwilliger, Steve Johnston, Rebecca Wai, Peter Hacke, Dana Kern. National Laboratory of the Rockies, Golden, CO, USA |
Abstract
UV-downshifting (UV-DS) packaging materials transfer higher energy optical flux to lower energy wavelengths that may be used to improve module efficiency and/or to protect module components from UV degradation. This study examines the operation, performance, and durability of two UV-DS encapsulants, composed of polyolefin encapsulant (POE) and poly(ethylene-co-vinyl acetate) (EVA). The POE and the coextruded EVA/POE/EVA (EPE) encapsulant sheet were laminated into glass/encapsulant/glass coupons. Characterizations include: UV-Vis fluorescence spectrometry, UV-Vis spectrophotometry, UV-fluorescence (UVF) imaging, and photoelasticity (PE) imaging. UV weathering was performed according to IEC TS 62788-7-2 at three chamber temperature conditions (65, 75, and 85 °C) and 20% RH, with a Xenon lamp at the intensity of 0.8 W×m-2 at 340 nm. While similar in operation and performance, the durability of the two encapsulants was readily distinguished. The more immediate degradation of the POE at lower temperature was attributed to the depletion of the additive(s) facilitating fluorescent excitation. The local degradation occurring at the periphery of the EPE coupons at higher temperature suggests a sensitivity to water and/or oxygen, occurring in addition to increased residual strain from densification at the center of the UV-DS encapsulant coupons.
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No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the author.
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