Surface Stress Characterization and Trends in Thermally Strengthened Photovoltaic Module Glass

作者：Elizabeth C. Palmiotti, Timothy J. Silverman, Michael G. Deceglie, Ingrid Repins, E. Ashley Gaulding · 发表于：IEEE Journal of Photovoltaics · 年份：2026 · DOI：10.1109/jphotov.2026.3668779 · 被引用次数：1 · 研究领域：Structural Analysis of Composite Materials、Chemical and Physical Properties of Materials、Advanced Materials and Semiconductor Technologies

Simultaneous changes in photovoltaic (PV) module architecture—such as increased area, replacing the polymeric backsheet with a glass backsheet, and reducing glass thickness from 3.2 to 2.0 mm—have resulted in a novel failure called spontaneous glass breakage. Spontaneous glass breakage results in front and/or rear glass failure without any obvious cause. The resulting low-energy fracture patterns have raised concerns about the thermal strengthening in 2.0-mm glass. We present validation of a nonde structive method for measuring the glass surface stress in PV modules. We use a scattered light polariscope to examine the glass properties of 11 modules from 6 solar fields, with and without spontaneous glass breakage. Based on a Mann–Whitney testp-value of 1.4 × 10−6, we conclude that there is a correlation between lower surface stress and susceptibility to spontaneous breakage. A Kendall's Tau testp-value of 2.0 × 10−4indicates a correlation between increased module area and lower surface stress. We find that 2.0-mm glass can be, and often is, fully tempered (surface stress ≥69 MPa), but inspecting the fracture pattern is not a reliable way to assess the amount of thermal strengthening. A combination of factors, not just surface stress, influences glass breakage.