Electroluminescence-Testing Induced Crack Closure in PV modules
Hubert Seigneur1, Andrew Gabor2, Jason Lincoln1, Eric Schneller1
1University of Central Florida, Orlando, FL, United States
/2BrightSpot Automation, Westford, MA, United States

Electroluminescence (EL) measurements of PV modules with cracked cells have showed some opened cracks to close arbitrarily from one day to another even though these modules are stored in a controlled, stressor free laboratory environment – constant temperature and no mechanical load. We have found that variations in current and temperature generated from joule heating during EL measurements strongly influence crack closure whereas a comparable increase in the ambient temperature alone does not seem to cause cracks to close. Because cracks closure inevitably lead to some gain in maximum power, we consider the ramifications for IEC standards, namely that performing EL measurements before I-V measurements may lead to inflated results.