Process optimization for Potential Induced Degradation improvement on cell level

Abstract

The Potential Induced Degradation (PID) has been known one of the important quality indexes of photovoltaic cells and modules in last few years. There have been several PID stability test methods and researches to explain the root cause of PID to achieve one common goal, a robust PV cell/module/system for longer lifetime. In this study, we have demonstrated process optimization techniques to improve cell-level PID performance. The Anti-Reflection Coating (ARC) layer has been optimized for better film quality. Further optimization of dual ARC layer design is applied to improve PID resistant capability. By using above techniques, within 5% degradation and no EL darkened area after PID test was obtained. Furthermore, it is known that PID performance and cell efficiency are trade-off, better PID performance will cause efficiency degradation. In this study, we successfully demonstrated cell efficiency gain by 0.3%abs with our PID-free process. Detailed process and PID measurement results will be discussed based on optimized process techniques.