Electrochemical Degradation Modes in Bifacial Silicon Photovoltaic Modules: Special Issue: EU PVSEC

Dana Sulas-Kern, Michael Owen-Bellini, Paul Ndione, Laura Spinella, Archana Sinha, Sona Ulicna, Steven Johnston, Laura Schelhas

Research output: Contribution to journalArticlepeer-review

12 Scopus Citations

Abstract

Motivated by the rapidly rising deployment of bifacial monocrystalline-silicon photovoltaics (PV), we investigate the durability of various PV module packaging configurations with transparent coverings on both the front and rear sides of the module. We use a series of bifacial passivated emitter and rear cell (p-PERC) mini-modules with systematically varying outer cover materials (glass/glass, G/G, or glass/transparent backsheet, G/TB) and encapsulant chemistries (poly [ethylene-co-vinyl acetate], EVA; or polyolefin, POE). We study degradation modes over 1,000 hours of combined damp heat (DH) exposure and high system voltages that can cause potential-induced degradation (PID) under positive, zero, or negative 1,000 V cell-to-frame bias. We analyze the degradation modes using a combination of current–voltage measurements, impedance spectroscopy, external quantum efficiency, and spatially resolved luminescence and thermal imaging. Our results highlight various types of degradation including shunting, enhanced recombination, and series resistance increases, and we use spatially resolved characterization to separately identify the localized effects. We show that multiple PID and moisture-ingress degradation modes severely affect EVA-containing modules, with previously reported PID processes under negative-bias DH and a unique observation of rear-side surface recombination in G/EVA/G modules under positive-bias DH. We observe significantly less degradation in POE-containing modules, where the G/POE/G configuration exhibits minimal degradation under all stress conditions that we employ.

Original languageAmerican English
Pages (from-to)948-958
Number of pages11
JournalProgress in Photovoltaics: Research and Applications
Volume30
Issue number8
DOIs
StatePublished - 2022

Bibliographical note

Publisher Copyright:
© 2021 John Wiley & Sons, Ltd.

NREL Publication Number

  • NREL/JA-5K00-80413

Keywords

  • bifacial
  • DuraMAT
  • PERC
  • reliability
  • silicon

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