Methodology and Systems to Ensure Reliable Thin-Film PV Modules

The reliability of Uni-Solar triple-junction amorphous silicon thin-film PV modules is very important to their success in an increasingly competitive PV market. Modules must show useful operating lifetimes on the order of 20 to 30 years, and although module efficiency is very important, the total energy a module will produce is largely dependent on its operating lifetime. Thus, it is essential to evaluate module reliability in order to estimate module lifetime and establish customer warranty periods. While real world outdoor exposure testing is necessary and important, it is essential that accelerated environmental test methods are utilized to provide more rapid feedback regarding failure modes, design flaws and degradation mechanisms. The following paper gives an overview of the methodology used to ensure long-term reliability of Uni-Solar flexible thin-film modules. The applied test methods are primarily based upon accepted industry test standards such as IEC-61646, UL-1703, and ASTM. The design, screening, and qualification process to ensure the robustness of new designs is described as well as subsequent module validation testing and manufacturing process control. Test methods important for flexible module laminates are briefly discussed and examples of reliability tests are given. Upon successful design validation and certification, the quality and reliability of manufactured modules is maintained through supplier and product quality assurance programs.