Optimized Light Management: New Test to Reduce Optical Losses in Solar Modules

© Fraunhofer CSP

Detail of a Solar Module.

The Fraunhofer Center for Silicon Photovoltaics CSP and the companies f solar GmbH, KURARAY Europe GmbH and SCHLENK AG work together to achieve an efficiency enhancement of solar modules: The three companies combine their respective products in test modules and search for best possible combination. To this end, the Fraunhofer CSP developed a novel characterization method to examine and evaluate all single components. The exact adjustment of each single component added to an efficiency enhancement of more than five percent in the created new joint system.

The Fraunhofer Center for Silicon Photovoltaics CSP and the companies f solar GmbH, KURARAY Europe GmbH und SCHLENK AG work together to achieve an efficiency enhancement of solar modules: The three companies combine their respective products in test modules and search for best possible combination. To this end, the Fraunhofer CSP developed a novel characterization method which examines and evaluates all single components. The exact adjustment of each single component adds to an efficiency enhancement of more than five percent in the created new joint system.

The objective pursued by the three companies was to reduce the optical losses of solar modules and thus maximize the total yield. For this reason, 2mm-thin solar glass with an antireflective coating (ARC) from f solar was combined with a special UV-permeable polyvinyl butyral plastic foil (PVB) from Kuraray and light harvesting strings (LHS) from Schenk, a surface-improving cell connector endowed with longitudinal grooves, in one solar module. The independent research institute Fraunhofer CSP examined which improvements resulted from each of combinations. An electrical and optical characterization method was used which analyzed, defined and verified the actions and interactions of each single component in the »overall module system«.

The solar modules were manufactured at the Fraunhofer CSP and their electrical and optical characteristics analyzed. A great number of 1-cell mini modules of various material combinations were made, subsequently optimized 54-cell modules, and compared with standard modules: »We were able to demonstrate that the optical losses in the combined (glass-glass) modules with 2mm- glasses with antireflective coating, special UV-permeable PVB and LHS connectors could be reduced by almost 40 percent as compared with the standard module,« explained Dr. Jens Schneider, Director of the Module Technology Center of the Fraunhofer CSP. The resulting power gain from all approaches to reduce optical losses were measured in 54-cell modules. In comparison with a conventional module, electricity and efficiency increased relatively by more than five percent.