Probing interconnection defects in solar modules via LBIC phase mapping

The electrical performance and reliability of photovoltaic modules are strongly influenced by the quality of the interconnections between cells. In this study, advanced Light Beam Induced Current (LBIC) phase mapping was utilized to assess local electrical behavior in half-cell samples before and after lamination. The interconnections were made with intentionally varied quality in different regions. After lamination, all regions exhibited increased phase shifts, with poorly connected areas showing significantly higher values, attributed to increased local series resistance. Cross-sectional optical and scanning electron microscopy (SEM) imaging confirmed the presence of gaps at poorly soldered contacts, supporting the electrical observations. This study demonstrates that LBIC phase mapping, supported by microscopic imaging, is a highly sensitive method for detecting interconnection defects and provides valuable feedback for improving solar module manufacturing.