Acceleration factor for damp heat testing of PV modules

Arun Bala Subramaniyan, Archana Sinha, Shantanu Pore, Hamsini Gopalakrishna, Rong Pan, Govindasamy Tamizhmani

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Interconnect Metallization System (IMS) degradation of photovoltaic (PV) modules is one among the major degradation modes in the field caused by higher operating temperatures and daily/seasonal/cloud cyclic temperatures. Usually, the acceleration factor (AF) and activation energy (Ea) of IMS degradation are determined based on power degradation data. Using power degradation data may not be fully representative of a specific mechanism since the power drop could be caused by multiple degradation mechanisms. In this paper, we have used the series resistance (Rs) increase, instead of power degradation, to obtain the AF and Ea for IMS degradation mechanism in the damp heat test (85°C/85% RH). The degradation data were sourced from our qualification damp heat test database with 94 crystalline silicon modules, and two field databases of Arizona and New York climates with 615 and 236 crystalline silicon modules, respectively. A 3-step approach was implemented to determine the AF for the damp heat testing. First, the AF for the field-to-field degradation was determined based on Rs degradation rates of the modules in Arizona and New York. Second, the Ea was determined based on the AF, and hourly differences in field-to-field module temperature and relative humidity. Third, the AF was determined based on Rs increase in the damp heat test and the Ea determined using the field data in the second step. A model based on modified Peck's equation was used to determine a generic AF for the Rs increase in qualification damp heat testing. This approach is useful to predict the service lifetime and reliability of PV modules for specific climatic regions.

Original languageEnglish (US)
Title of host publicationNew Concepts in Solar and Thermal Radiation Conversion and Reliability
EditorsJeremy N. Munday, Michael D. Kempe, Peter Bermel
ISBN (Electronic)9781510620896
StatePublished - 2018
EventNew Concepts in Solar and Thermal Radiation Conversion and Reliability 2018 - San Diego, United States
Duration: Aug 19 2018Aug 21 2018

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


OtherNew Concepts in Solar and Thermal Radiation Conversion and Reliability 2018
Country/TerritoryUnited States
CitySan Diego


  • Acceleration factor
  • Activation energy
  • Damp heat testing
  • Interconnect metallization system
  • PV module
  • Reliability

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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