Holistic Analysis for Mismatch Losses in Photovoltaic Modules: Assessing the Impact of Inhomogeneity from Operational Conditions and Degradation Mechanisms on Power and Yield

This study investigates mismatch losses in PV modules, analyzing the impact of operational conditions and degradation mechanisms on power generation across different module designs: full-cell, half-cell, string-shingled, and matrix-shingled. A bottom-up multi-physics model assesses inhomogeneities like partial shading, temperature inhomogeneity, soiling, encapsulation aging, and bypass diode failure. Module design related analysis reveals that parallel connections within modules minimize current mismatch losses, enhancing power under partial shading. Furthermore, modules exhibit a temperature profile with maximum temperatures at the center and minimum at the corners, impacting power differently based on the module's internal geometry, cell size, and electrical layout. Degradation analysis reveals significant power reduction due to soiling width and orientation, with encapsulation aging causing a 2% power loss after 3000 h. Findings indicate that partial shading and bypass diode failure can reduce full-cell module power to zero under vertical shading; half-cell and shingled modules retain varying power under horizontal and diagonal shading. Matrix-shingled modules perform best under partial shading due to additional lateral current paths. Yield analysis shows a 1.7-kWh annual yield increase for the matrix-shingled module, attributed to changes in cell-specific irradiance and temperature from its unique design, compared to a 0.5-kWh increase for the full-cell module. It was observed that shingled modules have a 1.6% higher specific yield under accumulating soiling along the long edge, which drops to 0.4% when considering module cleaning. For soiling along the short edge, results show that full-cell modules exhibit the highest specific yield. Furthermore, findings indicate that portrait mounting reduces annual yield by about 5% for shingled modules, compared to 3% for full-cell and half-cell modules, with landscape mounting having a lower negative impact on yield. Overall, this research identifies the strengths and weaknesses of various PV module designs under different degradation and inhomogeneity scenarios, advancing the development of more efficient modules and enhancing accurate energy yield predictions, thus significantly contributing to the sustainability of solar energy.