PV defects identification through a synergistic set of non-destructive testing (NDT) techniques

Kaplanis, Socrates, Kaplani, Eleni ORCID: https://orcid.org/0000-0002-4987-4388 and Borza, Paul Nicolae (2023) PV defects identification through a synergistic set of non-destructive testing (NDT) techniques. Sensors, 23 (6). ISSN 1424-8220

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A synergistic set of NDT techniques, including I–V analysis, UVF imaging, IR thermography, and EL imaging, supports a diagnostics methodology developed in this work to qualitatively and quantitatively identify a wide range of PV defects. The methodology is based on (a) the deviation of the module electrical parameters at STC from their nominal values, for which a set of mathematical expressions was developed that provide an insight into potential defects and their quantitative impact on the module electrical parameters, and (b) the variation analysis of EL images captured at a sequence of bias voltages for a qualitative investigation on the spatial distribution and strength of the defects. The synergy of these two pillars, supported by UVF imaging, IR thermography, and I–V analysis cross-correlating their findings, makes the diagnostics methodology effective and reliable. It was applied on c-Si and pc-Si modules operating from 0–24 years, exhibiting a diversity of defects of varying severity, either pre-existing or formed by natural ageing or externally induced degradation. Defects such as EVA degradation, browning, corrosion in the busbar/interconnect ribbons, EVA/cell-interface delamination, pn-junction damage, e−+hole recombination regions, breaks, microcracks, finger interruptions, and passivation issues are detected. Degradation factors triggering a cascade of internal degradation processes through cause and effect are analysed and additional models are proposed for the temperature pattern under current mismatch and corrosion along the busbar, further empowering the cross-correlation of NDT results. Power degradation was determined from 1.2% in 2 years of operation to more than 50% in modules with film deposition.

Item Type: Article
Additional Information: Data Availability Statement: The data presented in this study are available on request from the corresponding author.
Uncontrolled Keywords: pv defects and diagnostics,ndt techniques,electroluminescence,uv fluorescence imaging,ir thermography
Faculty \ School: Faculty of Science > School of Engineering
Depositing User: LivePure Connector
Date Deposited: 10 Mar 2023 13:30
Last Modified: 10 Mar 2023 13:30
URI: https://ueaeprints.uea.ac.uk/id/eprint/91457
DOI: 10.3390/s23063016

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