Evaluation of two‐dimensional electrical properties of photovoltaic modules using bias‐dependent electroluminescence

Abstract

ABSTRACT An approach to deriving two‐dimensional maps of cell and module electrical properties from electroluminescence imaging is presented. The technique involves quantitative comparison of the intensity differences in the electroluminescence images at different bias currents, enabling the derivation of junction voltages of individual pixels. These data were then fitted to a distributed electrical model that allows the derivation of a two‐dimensional dark I–V curve for each point across the module. Interpretation of the dark I–V curve enabled the evaluation of series resistance, shunt resistance, ideality factor, and reverse saturation current for each pixel. These parameters were then used to enable the prediction of module performance under illumination. Copyright © 2011 John Wiley & Sons, Ltd.