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Title:
 
Field Characterization of Silicon Solar Module Backsheets by Near-Infrared Absorption (NIRA) Spectroscopy
 
Author(s):
 
O. Stroyuk, T. Pickel, T. Winkler, C. Buerhop-Lutz, J. Hauch, I.M. Peters
 
Topic:
 
PV Systems – Modelling, Design, Operation and Performance
Subtopic: Operation, Performance and Maintenance of PV Systems
Event: 38th European Photovoltaic Solar Energy Conference and Exhibition
Session: 5CV.2.42
ISBN: 3-936338-78-7
 
Price:
 
 
0,00 EUR
 
Document(s): poster
 

Abstract/Summary:


Failures of silicon wafers and degradation of backsheets (BSs) are currently recognized as two major factors affecting performance and lifetime of crystalline Si solar modules. While a number of efficient fieldapplicable techniques were proposed to characterize Si solar cells and modules, almost no reports can be found on characterization of polymer BS and encapsulant materials directly in the field. In this paper, we introduce a field-ready spectroscopic tool for fast and non-intrusive identification of the composition and structure of polymer BSs by using near-infrared absorption (NIRA) spectroscopy. The feasibility of NIRA characterization was established during a field measurement campaign on a multi-MWp power station with a variety of module types. During the campaign, we identified the composition of about 500 modules and associated with the module performance as well as with IR/EL images. The NIRA analysis is based on preliminary lab identification of the BS structure by using Raman and FTIR spectroscopies. Scientific innovation and relevance. NIRA spectroscopy was applied for the first time for a large-scale field identification of BS composition of silicon solar modules in combination with other techniques allowing relationships between the module performance, degradation state and modes of failure to be associated with BS compositions and structures. The presented results are relevant for the development of high-throughput monitoring approaches for solar power stations operating in different climatic conditions as well as for failure analysis of new emerging module types and polymer BS/encapsulant materials. Results and Conclusions. The feasibility of large-scale field spectroscopic BS characterization was tested on a multi-MWp solar power station in Germany with a variety of module of various power classes and BS types produced by a single major manufacturer and commissioned in 2012. First, a representative set of BS samples was collected on the solar power station, the polymer BS components identified by Raman /FTIR spectroscopies in the lab, and multi-spectral Raman maps of BS cross-sections built for each particular BS type visualizing the BS structure (composition, number and thickness of layers). NIRA spectra of BSs with different structures are unique and clearly recognizable for each particular BS cross-section, allowing NIRA spectroscopy to be used as a self-standing tool for field measurements. A field measurement campaign was performed with a combination of