Title:	LeTID in Real Life: Incoming Cell Qualification for Module Manufacturers
Author(s):	A. Ciesla, M. Kim, A. Teymouri, L. Wang, C. Chan, R. Chan, P. Manshanden, B. Van Aken, J.J. Dijksterhuis, B. Hallam, G. Coletti
Keywords:	Degradation, Light-Soaking, Solar Cell, p-Type, PERC, Silicon, LID, Photovoltaic, Czochralski
Topic:	Photovoltaic Modules and BoS Components
Subtopic:	Materials for PV Modules, Durability, Reliability and Accelerated Testing Methods
Event:	8th World Conference on Photovoltaic Energy Conversion
Session:	3EO.1.1
ISBN:	3-936338-86-8
Price:	0,00 EUR
Document(s):	presentation

Abstract/Summary:

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Light- and elevated Temperature- Induced Degradation (LeTID) can affect all types of silicon wafer and cell, especially the industry dominant PERC cell. It is highly dependent on the field or accelerated test conditions. Module manufacturers often have little understanding of the LeTID susceptibility of the cells that they source. In this work, we investigate the severity of LeTID in eight currently available commercial mono-PERC cells from four different cell manufacturers. Four cell types were found to degrade significantly, reaching 1-2% degradation after 1000 hours under 80 C, 1-sun test conditions and still appear to be slowly degrading. More significant degradation is seen at 60 C, which is more representative of a continental climate. The cell type with the most significant degradation is known to be gallium doped, while two other cell types displayed behaviour consistent with co-existing boron-oxygen (BO) LID and LeTID. One of the latter types and the gallium doped cell type have been selected for an ongoing study involving LID and LeTID treatments prior to module fabrication and installation in the Netherlands to study the impact of such treatments on the long-term stability in a continental climate.