Search

Abstract The research project INFINITY focuses on design improvements for PV system components operating in different climatic regions. This topic gained pertinence in recent years due to increased installation rates worldwide with the highest growth rates in non-moderate climates. As PV components are not optimized to the respective climate zone, the target of the project is to gather failure data from PV installations in various climate zones. A standardized data input was achieved by using an extended format of the IEA PVPS Task 13 failure survey, allowing to enter PV system and failure information in rich detail. The components' and failure structure were elaborated by combining input from reliability workshop proceedings, PVPS Task 13 and project partners' experience in PV reliability testing. These structures were mapped into a database to collect and prepare the input for further statistical analysis. Collected data was filtered, offering a tidy data set of 1048 samples from 340 sub-systems from 45 countries worldwide. After data filtering, a power loss evaluation, a cluster analysis and a trend analysis were performed. This paper presents results of comparing PV module failures in different climate zones starting with a range of PV systems installed in the 1970s, to recently installed systems. Highlights • Comparison of PV module failures in different climate zones. • 1048 failures from 340 sub-systems in 45 countries all over the world. • Prevailing failures in the main climate zones (A-D) were identified. • A cluster analysis shows typical combinations of failures in various climate zones. • A trend analysis indicates different time to failure in individual climate zones. [ABSTRACT FROM AUTHOR]

In photovoltaics, the quality of the polymeric solar cell embedding material is of key importance for the long-term durability and performance of the PV modules. For the most common encapsulant, elastomeric ethylene vinyl acetate (EVA), the degree of crosslinking is a key issue in this respect. Raman spectroscopy was researched as a fully contact-free, truly non-destructive optical method to measure the degree of EVA crosslinking of bare EVA film samples as well as in-situ inside assembled PV modules. The method relies on evaluating subtle but characteristic spectral differences in the CH-stretching vibration region (3.000–2.800 cm −1 ) that correlate directly, unambiguously and reliably to the crosslinking state of the EVA encapsulant. With measurement times below one second per analysis point, the method is suitable for real-time, in-line quality control. Using a self-referencing data evaluation approach, the method could be designed to be widely immune to real-world effects, including different sample reflectivity and instrument drifts. Involving the reaction kinetics of the curing reaction, the Raman data can be converted into crosslinking readings that equal the traditional, Soxhlet-derived gel content values. The method has been successfully validated for bare foils, glass–backsheet and glass–glass modules with three different EVA types and deployed in-line in a commercial PV module manufacturing line. Using Raman spectroscopy, it is thus possible to determine the degree of crosslinking of the EVA encapsulant inside assembled modules in-line and with high accuracy, even on moving modules. [ABSTRACT FROM AUTHOR]

Since the beginning of PV module production, Soxhlet extraction has been the standard method for the determination of the gel content and the resulting calculation of the degree of crosslinking of the most common PV encapsulant ethylene vinyl acetate (EVA). While the method is deemed well established and several pertinent ASTM and ISO standards exist, in practise the actual procedures used in – and trusted by – both industry and R&D institutions vary substantially. To evaluate the reliability of the methods and the comparability of the results, a round-robin test involving seven independent European laboratories – one industrial PV module manufacturer and six R&D facilities – was conducted. The measurements were performed using homogenous, anonymized sample sets, each comprising five differently crosslinked EVA foils. The analysis showed that results obtained for the same samples may deviate significantly, but also that very different analytical procedures can yield comparable values. In a systematic study, the impact of various key parameters of the analytical process (extraction time and solvent, drying conditions, sample size and weight etc.) was investigated. Based on these findings, deviations observed in the round-robin study could be linked to their origins and the main pitfalls were identified. In conclusion, a suggestion for an optimised standard procedure was derived to ensure comparable results at all laboratories. [ABSTRACT FROM AUTHOR]

Abstract Over the last years, the development of innovative, fast and non-destructive characterisation techniques for the detection of PV-module failures and advanced analysis of yield losses in photovoltaic power plants has become a key challenge in scientific research. Besides standard on-site thermographic screening, several novel and easily applied methods were developed and successfully tested. They differ mainly in their possible field of application, their applicability in the detection of different failure types and their cost of setup and operation. In order to evaluate the boundary conditions of application for the various methods, different defective PV-modules were comparatively investigated with commercially available and innovative outdoor analysis methods. The results were evaluated with regard to error detection rate and economics. Based on this comparison, efficient operation and maintenance (O&M) measures for early and general failure detection within large power plants can be deducted. Highlights • A systematic comparison with help of most known inspection devices was done on faulty PV modules on site. • A comprehensive analysis of standard PV module failures resulted in a decision matrix. • With only one inspection method, not all faulty PV modules can be found. • The usage of multiple inspection devices is a requirement to classify a failure correctly. [ABSTRACT FROM AUTHOR]