New module design with 4-junction solar cells for high efficiencies

CPV systems using 3-junction solar cells have proven good performance and reliability. As the performance of 3-junction cells is saturating [1], the logical next step is the introduction of 4-junction (4-J) solar cells into CPV modules. The current world record for cell efficiency under concentrated light of 46.0% was achieved using a wafer bonded Soitec 4-J cell (SmartCell™) [1-4]. This paper discusses a new module design, optimized for harvesting the full potential provided by this high cell efficiency. Prototype modules have been built in order to explore the design space. A module efficiency of 38.9% under concentrator standard test conditions has been achieved.