The Fraunhofer Institute for Solar Energy Systems ISE employed their newest CPV module technology, known as Flatcon, which uses Frensnel lenses to focus sunlight onto small solar cells. The researchers of Freiburg, Germany, announced a world record module efficiency of 36.7 %. The team adapting the concentrating lens to a new solar cell structure to achieve the record efficiency under Concentrator Standard Testing Conditions, or CSTC. The researchers claim that the achievement is the highest efficiency ever (under that level of light concentration) for a photovoltaic module.
The team used Soitec’s newly developed four-junction solar cell based on Soitec’s wafer bonding technology that the company developed in cooperation with Fraunhofer ISE. Recently this four-junction solar cell was implemented into the Institute’s FLATCON® module concept. The module aperture area exposed to light, is 832 cm². The sunlight was concentrated by a factor of 230 suns onto fifty-two 7 mm² miniature solar cells with the help of fifty-two 16 cm² Fresnel lenses.
“Naturally we are incredibly excited about this high module efficiency,” said Dr. Andreas Bett, who has led the CPV research at Fraunhofer ISE over many years. “This success shows that the high efficiencies of Soitec’s novel four-junction solar cells can be transferred to the module level.”
Several months ago, Fraunhofer ISE along with Soitec, the French research center CEA-Leti, and the Helmholtz Center in Berlin announced a new solar cell world record of 44.7 % under concentrated light. This record cell consisted of four sub-cells made up of the compound semiconductors GaInP, GaAs, GaInAs and InP respectively. Industry partner ORAFOL manufactured the Fresnel lenses. The successful transfer of this high module efficiency to commercially manufactured modules is expected within one to two years.