Presentation Details
| Insights into the material properties of EPE encapsulants for PV application (yes) Nikolina Pervan1, 2, Gabriele C.Eder3, Yuliya Voronko3, Gernot Oreski1, 2. 1Polymer Competence Center Leoben GmbH, Leoben, Austria.2Chair of Materials Science and Testing of Polymers, Montanuniversität Leoben, Leoben, Austria.3Österreichisches Forschungsinstitut für Chemie und Technik (OFI), Vienna, Austria |
Abstract
Coextruded ethylene vinyl acetate - polyolefin - ethylene vinyl acetate (EPE) encapsulant films were developed to support the technological transition in photovoltaic modules (PV) towards higher-efficiency solar cells that are more sensitive to moisture than previous generations. EPE was designed to combine cost-effectiveness and processability of ethylene vinyl acetate (EVA) with the superior electrical insulation and moisture barrier properties of polyolefin (POE). This study systematically investigates the chemical, optical, thermal, and thermo-mechanical properties of four commercially available EPE encapsulants. While the outer EVA layers were comparable across all samples, differences arose in the inner polyolefin layer. EPE-1 contains an ethylene acrylate copolymer, whereas EPE-2, -3, and -4 feature ethylene α-olefin copolymer cores with varying side groups and comonomer content. All EPE films showed significantly lower water vapor transmission rates (WVTR) compared to EVA. Thermal analysis revealed differences in crosslinking behavior, EPE-1 was the only sample with a non-crosslinking inner polyolefin layer, whose high crystallinity reduced visible-light transmission but also enhanced barrier to water vapor. The co-extrusion process appeared to improve the dimensional stability of EPE-2; -3; -4, compared to standard EVA. The observed reduction in WVTR highlights the potential of EPE, but further studies are needed to determine their behavior over long-term environmental exposure.
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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.