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 members agreed that the following items are important areas of future work:

Evaluating component testing versus full-size testing, in coordination with Task Group 5
Conducting outdoor accelerated testing with increased 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 tests, study new modes with factors of UV light, thermal cycling, desiccating environment, module size, and test combinations
Building robustness around test protocols with interlaboratory studies
Evaluating problems associated with new module technologies that have little to no fielded history
Evaluating acceleration factors: chamber/field
Evaluating extended and high-temperature testing: false positives and negatives.

Progress Update

Task group 3 was instrumental in developing test methods for potential induced degradation (PID). These test methods were published in IEC TS 62804-1:2015, "Photovoltaic (PV) modules - Test methods for the detection of potential-induced degradation - Part 1: Crystalline silicon ", and IEC TS 62804-1-1:2020 "Photovoltaic (PV) modules - Test methods for the detection of potential-induced degradation - Part 1-1: Crystalline silicon – Delamination. " Test methods from IEC TS 62804-1 were integrated into module design qualification requirements in IEC 61215-2: 2021. A new draft of IEC TS 62804-1 is underway, introducing new test methods for PID-polarization. IEC TS 62804-2, which can determine an acceleration factor for PID in thin film modules, was published in 2022.

Task group 3 members contributed to IEC TR 63279:2020, "Derisking photovoltaic modules - Sequential and combined accelerated stress testing. "

A new work item related to coupled-stress acceleration test sequence for photovoltaic modules and materials (IEC TS 63556 ED1) was introduced in IEC working group 2 in 2024.

Standards Activities

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

IEC TS 62804-1-1:2020: PV modules – Test methods for the detection of potential-induced degradation – Part 1-1: Crystalline silicon – Delamination.

IEC 62788-5-1:2020 ED1: Measurement procedures for materials used in photovoltaic modules - Part 5-1: Edge seals - Suggested test methods for use with edge seal materials. Published March 2020

IEC 62788-6-2:2020: Measurement procedures for materials used in photovoltaic modules - Part 6-2: General tests - Moisture permeation testing with polymeric materials. Published March 2020

IEC TR 63279:2020, "Derisking photovoltaic modules - Sequential and combined accelerated stress testing."

IEC TS 62804-2 ED1:2022: PV modules – Test methods for the detection of potential-induced degradation – Part 2: Thin film

Related Resources

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)

Development of Combined and Sequential Accelerated Stress Testing for Derisking Photovoltaic Modules: 2019
Presenter: Hacke, P.L.

Polarization Type Potential Induced Degradation under Positive Bias in a Commercial PERC Module: 2023
Authors: Mahmood, F.i.; Li, F.; Hacke, P.L.; Molto, C; Siegneur, H.; TamizhMani, G.

Field-representative evaluation of PID-polarization in TOPCon PV modules by accelerated stress testing: 2024
Authors: Hacke, P.L.; Spataru, S.; Habersberger, B.; Chen, Y.

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.