Suppression of the shunting-type potential induced degradation (PID-s) through ion exchange on soda lime silicate glasses

Abstract

This study investigates the potential of chemically strengthened soda-lime-silicate (SLS) glass to mitigate Potential Induced Degradation (PID-s) caused by the shunting mechanism in photovoltaic (PV) modules, a key factor in efficiency losses in these systems. PID-s primarily results from the migration of sodium ions (Na⁺) from the SLS glass into the cell junctions, leading to reduced performance. In this study, we modified commercial SLS glass through an ion exchange process, substituting Na⁺ ions with potassium (K⁺) ions, which have a larger ionic radius, to improve resistance to PID-s. The modified glass was tested in a PIDcon Bifacial Device under accelerated test conditions, and the results were compared with untreated SLS glass. The findings showed that chemically strengthened SLS glass with K⁺ content significantly reduced Na⁺ migration compared to standard SLS glass. Given that cover glasses are the primary structural elements in PV modules, we also examined the mechanical properties and demonstrated that the ion exchange process improved the strength of the SLS glass by introducing a surface compressive stress state. Our results suggest that SLS glass, commonly used in the PV module industry, is a cost-effective solution for reducing PID-s degradation, and integrating this feature into modules does not necessitate the use of more expensive glass compositions, such as aluminosilicates, which are typically used for ion exchange treatments.