Identification and characterisation of performance limiting defects and cell mismatch in photovoltaic modules
| Autor: | E. Ernest van Dyk, Jacqui L. Crozier, Frederick J. Vorster |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Materials science
General Computer Science law.invention electroluminescence Positive current law Solar cell Electronic engineering Crystalline silicon lcsh:TJ163.26-163.5 cell mismatch lcsh:Environmental sciences degradation lcsh:GE1-350 business.industry String (computer science) Photovoltaic system Identification (information) photovoltaics General Energy lcsh:Energy conservation current-voltage characterisation Optoelectronics business Degradation (telecommunications) Voltage |
| Zdroj: | Journal of Energy in Southern Africa, Vol 26, Iss 3, Pp 19-26 (2017) Journal of Energy in Southern Africa, Volume: 26, Issue: 3, Pages: 19-26, Published: AUG 2015 |
| ISSN: | 2413-3051 |
| Popis: | The performance and longevity of photovoltaic (PV) modules can be severely limited by cell mismatch occurring when a solar cell in a series-connected string produces a lower current than the other cells in that string. The current output of the entire string is limited by the weakest cell in the string so shading or damage to a single cell in a module can affect the entire module’s current output. Electrolumin-escence (EL) occurs when a positive current and voltage are applied to a solar cell and is used to identify damage and defects in the cell. In this study, the cell mismatch in three single crystalline silicon modules was investigated using EL and current-voltage (I-V) characterisation techniques. Two modules have a white discolouration that affects the majority of the cells in the module and also have signs of mechanical damage, while the third module acts as a reference as it has no discolouration and appears undamaged. The EL signal intensity is related to cell performance and identifies material defects, bad contacts and broken cells. Cell mismatch in a module results in a decrease in the performance parameters obtained from the I-V characteristic curve of the module. The I-V curves indicate the presence of current mismatch in the degraded modules, which is supported by the EL images of these modules. The use of EL images, in conjunction with the I-V curves, allows the degradation in the modules to be characterised. |
| Databáze: | OpenAIRE |
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