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Significant reduction in arc frequency biased solar cells: Observations, diagnostics, and mitigation technique(s)A variety of experiments were performed which identify key factors contributing to the arcing of negatively biased high voltage solar cells. These efforts have led to reduction of greater than a factor of 100 in the arc frequency of a single cell following proper remediation procedures. Experiments naturally lead to and focussed on the adhesive/encapsulant that is used to bond the protective cover slip to the solar cell. An image-intensified charge coupled device (CCD) camera system recorded UV emission from arc events which occurred exclusively along the interfacial edge between the cover slip and the solar cell. Microscopic inspection of this interfacial region showed a bead of encapsulant along this entire edge. Elimination of this encapsulant bead reduced the arc frequency by two orders of magnitude. Water contamination was also identified as a key contributor which enhances arcing of the encapsulant bead along the solar cell edge. Spectrally resolved measurements of the observable UV light shows a feature assignable to OH(A-X) electronic emission, which is common for water contaminated discharges. Experiments in which the solar cell temperature was raised to 85 C showed a reduced arcing frequency, suggesting desorption of H2O. Exposing the solar cell to water vapor was shown to increase the arcing frequency. Clean dry gases such as O2, N2, and Ar show no enhancement of the arcing rate. Elimination of the exposed encapsulant eliminates any measurable sensitivity to H2O vapor.
Document ID
19910020921
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Upschulte, B. L. (Physical Sciences, Inc., Andover MA., United States)
Weyl, G. M. (Physical Sciences, Inc., Andover MA., United States)
Marinelli, W. J. (Physical Sciences, Inc., Andover MA., United States)
Aifer, E. (Boston Univ. MA., United States)
Hastings, D. (Massachusetts Inst. of Tech. Cambridge., United States)
Snyder, D. (NASA Lewis Research Center Cleveland, OH, United States)
Date Acquired
September 6, 2013
Publication Date
August 1, 1991
Publication Information
Publication: Space Photovoltaic Research and Technology Conference
Subject Category
Spacecraft Propulsion And Power
Accession Number
91N30235
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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