Degradation of Edge‐Defined Film‐Fed Silicon Glass–Glass Modules on Florida Rooftop After 22 Years

Abstract

Thin silicon () adoption can provide significantly lower cost. Kerfless technologies provide thin wafers while preventing material from being wasted. Understanding how this family of processing influences module reliability is important. A set of four edge‐defined film‐fed growth (EFG) silicon modules from a ten‐module system in Florida is measured after 22 years of exposure. Power loss rates of 0.58–0.78% year−1 are measured for three modules, while a rate of 1.32% is measured for a module with severe delamination and corrosion. Short‐circuit current degrades between 10.7% and 13.1% for all modules. The losses are primarily optical and recombination based; however, series and shunt resistance effects play a non‐negligible role. Pre‐existing recombination losses exist but are exacerbated via degradation. Optical losses in short‐circuit current are due in part to encapsulant yellowing. Electroluminescence (EL) images display the effects of processing on bulk quality by clearly showing lines of alternating brightness along the wafer length. To the authors’ knowledge, this is the first article displaying suns– data, effective lifetime versus excess carrier density data, and module EL images for EFG silicon‐based modules.