Acceleration Factors for Combined-Accelerated Stress Testing of Photovoltaic Modules

Peter Hacke, Michael Owen-Bellini, Michael Kempe, Dana Sulas-Kern, David Miller, Marko Jankovec, Stefan Mitterhofer, Marko Topic, Sergiu Spataru, William Gambogi, Tadanori Tanahashi

Research output: Contribution to journalArticlepeer-review

2 Scopus Citations


Combined-accelerated stress testing (C-AST) is developed to establish the durability of photovoltaic (PV) products, including for degradation modes that are not a priori known or examined in standardized tests. C-AST aims to comprehensively represent the sample, stress factors, and their combinations using levels at the statistical tails of the natural environment. Acceleration factors for relevant climate sequences within the C-AST cycle with respect to the Florida USA climate are estimated for selected degradation mechanisms. It is found that for degradation of the outer backsheet polymer layer, the acceleration factor of the tropical climate sequence (the longest of the climate sequences) is f (T, G) = 17.3 with ultraviolet photodegradation; for polyethylene terephthalate hydrolysis (backsheets), f (T, RH) = 426; for electrochemical corrosion (PV cell), f (I) = 14.1; and for PbSn solder fatigue f (ΔT, r (T)) = 17.3. Here, T is the module temperature, G is the broadband spectrum irradiance on the plane of array of the module, RH is the relative humidity on the module surface, I is the leakage current through the module packaging, and r(T), the number of temperature reversals. The methods discussed herein are generally applicable for evaluating acceleration factors in other accelerated test methods.

Original languageAmerican English
Article number2300068
Number of pages8
JournalSolar RRL
Issue number12
StatePublished - 2023

Bibliographical note

Publisher Copyright:
© 2023 The Authors. Solar RRL published by Wiley-VCH GmbH.

NREL Publication Number

  • NREL/JA-5K00-85971


  • accelerated testing
  • durability
  • photovoltaic modules
  • reliability


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