TY - JOUR
T1 - Electroluminescence and Dark Lock-In Thermography for the Quality Assessment of Metal-Wrap-Through Solar Devices
AU - Ruggeri, Edoardo
AU - van Aken, Bas
AU - Isabella, Olindo
AU - Zeman, Miro
PY - 2018
Y1 - 2018
N2 - Imaging techniques, like electroluminescence and dark lock-in thermography, are valuable quality control tools as they yield quantitative and spatially resolved information about the device. In this paper, we isolated some of the conductive foil–cell interconnections of back-contact solar cells to study the appearance of these intentional failures in electroluminescence, dark lock-in thermography, and series resistance images. It has been found that isolated emitter-to-foil contacts are clearly visible in the three imaging techniques, as they show characteristic features that deviate from the features typical of functioning emitter-to-foil dots. Isolated base-to-foil contacts are instead invisible in the images obtained by electroluminescence and only hardly visible in the images obtained by the other two techniques. Only after a large amount of contacts are isolated, a local current redistribution or drastic series resistance increase is noticeable. Two graphical methods for the automatic identification of isolated emitter-to-foil contacts in electroluminescence, dark lock-in thermography, and series resistance images were also designed, showing a success rate of 97% in the investigated cells. Such techniques could represent useful tools for implementation in inline quality control processes. Moreover, the techniques and conclusions drawn in this paper can be extended to a large number of other conventional and emerging photovoltaic technologies.
AB - Imaging techniques, like electroluminescence and dark lock-in thermography, are valuable quality control tools as they yield quantitative and spatially resolved information about the device. In this paper, we isolated some of the conductive foil–cell interconnections of back-contact solar cells to study the appearance of these intentional failures in electroluminescence, dark lock-in thermography, and series resistance images. It has been found that isolated emitter-to-foil contacts are clearly visible in the three imaging techniques, as they show characteristic features that deviate from the features typical of functioning emitter-to-foil dots. Isolated base-to-foil contacts are instead invisible in the images obtained by electroluminescence and only hardly visible in the images obtained by the other two techniques. Only after a large amount of contacts are isolated, a local current redistribution or drastic series resistance increase is noticeable. Two graphical methods for the automatic identification of isolated emitter-to-foil contacts in electroluminescence, dark lock-in thermography, and series resistance images were also designed, showing a success rate of 97% in the investigated cells. Such techniques could represent useful tools for implementation in inline quality control processes. Moreover, the techniques and conclusions drawn in this paper can be extended to a large number of other conventional and emerging photovoltaic technologies.
KW - Electrical resistance measurement
KW - electroluminescence
KW - failure analysis
KW - infrared imaging
KW - radiation imaging
KW - solar energy
UR - http://www.scopus.com/inward/record.url?scp=85050387715&partnerID=8YFLogxK
UR - http://resolver.tudelft.nl/uuid:b9ca8466-ce5f-45fa-8f6a-b081b215272c
U2 - 10.1109/JPHOTOV.2018.2850530
DO - 10.1109/JPHOTOV.2018.2850530
M3 - Article
AN - SCOPUS:85050387715
SN - 2156-3381
VL - 8
SP - 1174
EP - 1182
JO - IEEE Journal of Photovoltaics
JF - IEEE Journal of Photovoltaics
IS - 5
ER -