43 % direct sunlight conversion efficiency using 4J cell with achromatic full glass lens
In this work a direct conversion of sunlight with an efficiency of 43.4 % is demonstrated with a CPV mini-module. The mini-module consists of an achromatic full-glass lens and a wafer-bonded four-junction solar cell mounted to a heat sink. The 43.4 % efficiency was determined at IEC 62630-1 concentrator standard test conditions. The electrical characteristic of the full-glass lens mini-module was compared to a mini-module using a Fresnel lens. The Fresnel lens mini-module is affected by chromatic aberration whereas the impact of chromatic aberration on the full-glass lens mini-module is negligible. The measurement data gathered from the mini-modules is compared to a calculation performed with a combined ray tracing and network model. The comparison of model and simulation shows a good agreement. The simulation is used to demonstrate the series resistance losses due to lateral current flows caused by chromatic aberration.