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Humidity, Temperature, and Voltage: Task Group 3

Task Group 3 focuses on photovoltaic (PV) module degradation from humidity, temperature, and voltage. It's particularly cognizant of sample construction under test, inclusivity of stress factors of the natural environment, how they are combined or sequenced, and how their levels are chosen to achieve more successful evaluation of both known and yet unrecognized degradation modes.

The task group's original focus was on ingress of moisture and effects of electrical bias, which have been shown to cause corrosion and charge/ion transport degradation in PV modules. The group has studied the related degradation modes and their acceleration factors for development of true accelerated lifetime tests in consideration of specific climatic and module technology factors. This work has enabled the development or publication of several standards for evaluation of potential-induced degradation and moisture ingress.

More recently, the community has come to the understanding that for many degradation modes, multiple stress factors of the natural environment have a role
Task Group 3 held a discussion at the beginning of 2019 to prioritize areas of future work topics as follows:

  • Evaluating component testing versus full-size testing, in coordination with Task Group 5
  • Conducting outdoor accelerated testing and amplification of levels (temperature, relative humidity, system voltage, ultraviolet exposure)
  • Developing sequential and combined-accelerated stress testing, evolving existing tool sets, and modeling cost/benefits
  • Developing combined-accelerated stress testing, mode agnostic, study new modes with factors of UV light, thermal cycling, desiccating environment, module size, and test combinations
  • Developing an International Electrotechnical Commission (IEC) 61215/61730 alternative Building robustness around test protocols with interlaboratory studies
  • Evaluating new module technologies' (bifacial, thin cells, passivated emitter and rear cell) potential problems
  • Evaluating acceleration factors: chamber/field
  • Evaluating extended and high-temperature testing: false positives and negatives.

Progress Update

Task Group 3 continues to compare field failures with the results of stress tests to achieve better accelerated stress testing protocols. Group members are contributing to an IEC technical report titled, “Combined and Sequential Accelerated Stress Testing for Derisking Photovoltaic Modules,” and other related publications.

Standards Activities

IEC TS 62804-1:2015: PV modules – Test methods for the detection of potential-induced degradation – Part 1: Crystalline silicon. Published August 2015.

IEC TS 62804-1-1 ED1: PV modules – Test methods for the detection of potential-induced degradation – Part 1-1: Crystalline silicon – Delamination. In the draft technical specification phase.

IEC TS 62804-2 ED1: PV modules – Test methods for the detection of potential-induced degradation – Part 2: Thin film (and for modules with cells requiring moisture-barrier packaging). Committee reviewing second draft.

IEC 62788-5-1 ED1: Measurement procedures for materials used in photovoltaic modules - Part 5-1: Edge seals - Suggested test methods for use with edge seal materials. In final draft phase.

IEC 62788-5-2 ED1: Measurement procedures for materials used in photovoltaic modules - Part 5-2: Edge seals - Edge-seal durability evaluation guideline. Committee reviewing second draft.

IEC 62788-6-2 ED1: Measurement procedures for materials used in photovoltaic modules - Part 6-2: General tests - Moisture permeation testing with polymeric materials. In final draft phase.

Related Resources

IEC TS 63209 ED1: “Extended-stress testing of photovoltaic modules for risk analysis" is being developed by IEC Technical Committee 82.

Compendium of Photovoltaic Degradation Rates
Authors: Jordan, D. C., Kurtz, S. R., VanSant, K., & Newmiller, J.
Journal: Progress in Photovoltaics: Research and Applications

Crystalline Silicon PV Module Degradation after 20 Years of Field Exposure Studied by Electrical Tests, Electroluminescence, and LBIC
Authors: Pozza, A., & Sample, T.
Journal:  Progress in Photovoltaics: Research and Applications

Equating Damp Heat Testing with Field Failures of PV Modules
Authors: Wohlgemuth, J. H., & Kempe, M. D.
Conference: 2013 IEEE 39th Photovoltaic Specialists Conference (PVSC)

All-India Survey of Photovoltaic Module Degradation: 2013 PDF 
Authors: Dubey, R., Chattopadhyay, S., Kuthanazhi, V., John, J. J., Arora, B. M., Kottantharayil, Narasimhan, K. L., Solanki, C. S., Kuber, V., Vasi, J., Kumar, A., and Sastry, O. S.
Survey: National Centre for Photovoltaic Research and Education, Indian Institute of Technology, Bombay, and Solar Energy Centre, National Institute of Solar Energy, Gurgaon.

Task Leaders

While some materials are posted on the website, please contact your regional leader to more closely follow the activities.

Peter Hacke— National Renewable Energy Laboratory, representing the Americas
Tadanori Tanahashi —National Institute of Advanced Science and Technology, representing Japan
Alan Xu — Canadian Solar, representing China

Other leaders and regional groups are welcome.