Round‐robin weathering test of various polymeric back‐sheets for PV modules with different ultraviolet irradiation and sample temperatures

Michael Koehl,Allen Zielnik,Peter Hacke,Hung‐Sen Wu

doi:10.1002/pip.3275

Abstract

AbstractDurability assessment of materials exposed to natural weathering with expected service lifetimes of more than 20 years requires accelerated testing of the UV stability, especially for polymeric materials. Fraunhofer ISE organized an interlaboratory comparison for testing different back‐sheets in various test laboratories using different UV sources. The five participating test laboratories used three different types of UV sources. The interaction of the UV radiation with the polymers used in PV modules is main subject of this round‐robin. Laminates were produced by using solar glass and a suitable EVA encapsulant combined with 10 different back‐sheets. The simultaneous usage of different optical filters allowed to investigate roughly the spectral sensitivity and the intensity impact.The degradation was followed by spectral reflectance and transmittance measurements and calculation of the yellowness index as degradation indicator. Clear differences in the degradation behavior of the different products were found.

Highlights

Photovoltaic modules are used for the conversion of solar energy to electricity
Fraunhofer ISE organized an interlaboratory comparison for testing different back-sheets in various test laboratories using different UV sources
In case of increasing the intensity of the light source for accelerating the UV test, the overheating of the samples would have to be prevented more strictly, and the temperature of the samples have to be measured in order to avoid misinterpretation of the test results

Summary

Introduction

Photovoltaic modules are used for the conversion of solar energy to electricity. Durability testing of materials exposed to natural weathering requires testing of the UV stability, especially for polymeric materials.

Results

Conclusion