Prevention of potential-induced degradation using a moisture barrier in crystalline silicon photovoltaic modules

Abstract

As photovoltaic (PV) modules are exposed to high temperatures and humidity over time, they generate leakage current, which leads to potential-induced degradation (PID) and lower power output. In silicon, Cu(In,Ga)(Se,S)₂ (CIGS) thin film and perovskite solar cells, PID has been shown to be driven by the presence of Na in the module glass. PID stability is crucial for the commercialization of such solar modules. This study aims to confirm the leaching phenomenon of Na in soda–lime module glass and study the use of polytetrafluoroethylene (PTFE) as a moisture barrier to prevent PID. By water immersion and exposure to different temperature and humidity conditions, we exhibited Na leaching in soda–lime glass. Moreover, we demonstrate the use of an anti-PID moisture barrier made of PTFE, which was deposited using kinetic spraying between the cover glass and encapsulant in the solar module. The thickness of the moisture barrier was controlled by adjusting the deposition rate, and the PID characteristics were evaluated by manufacturing solar modules for different barrier thicknesses. Light current–voltage (LIV), dark current–voltage (DIV), and electroluminescence (EL) measurements confirmed that the PTFE moisture barrier effectively inhibits the degradation of solar cells. This study provides further insights into the Na leaching phenomenon and PID mechanism in PV modules and contributes to the design and development of more stable solar cells.