Current Measurement System for Solder Joint Quality Analysis in Photovoltaic Modules

This paper deals with a novel approach of using a multi frequency eddy current measurement system for analyzing the quality of solder joints in a photovoltaic (PV) module. Due to environmental conditions, thermal cycles and variable load situations the solder joints of the cell connectors inside a photovoltaic module suffer and properly lead to degradation or even worse to completely fail, which in turn can be accountable for burn marks, hotspots, arcing discharges and of course, substantial power losses. With the presented approach, the conductivity of each solder joint can be individually analyzed, enabling the possibility of early failure detection in-line or even in the field. The measurement results show that the evaluated states correlate to conductivity decrease of solder joints, which can be confirmed by electroluminescence (EL) images of a solar cell.