Indoor and outdoor testing of low weight flexible CIGS modules

Some of the critical advantages of the thin films are being light and flexible. These attributes of the thin films can be advantageously realized when thin film CIGS material is formed on flexible substrates such as stainless steel foils. However due to moisture sensitivity of the CIGS solar cells, commercial flexible CIGS modules that can meet the markets requirements and obtain formal certifications have been elusive. In this presentation, work will be presented that will describe the significant progress made in the field of flexible low weight CIGS modules. A significant milestone was reached when the formal certifications to UL 1703, IEC 61646, and IEC 61730 standards were obtained for the first time for flexible CIGS modules. These modules have excellent power levels reaching a 12.1 aperture efficiency as measured at NREL. Many accelerated tests including the damp humidity test (85C and 85% humidity) were performed in excess of 5000 hours. The results show that there is very little change in the Pmax of the modules and that the total power loss after 5000 hours of testing is less than 10%. Further accelerated indoor tests including temperature cycling and humidity freeze will be discussed and the results will be compared against the rigid CIGS modules. After obtaining the formal certifications, the modules were deployed outdoors and grid connected. The flexible CIGS modules perform very well with performance ratios exceeding 0.85. Additional indoor and outdoor test results will be presented.