At the 14th International CPV Conference in Puertollano, Spain, Juan Francisco Martínez Sánchez, doctoral student at Fraunhofer ISE, was distinguished with the Student Award for his talk "4-Terminal CPV Module Capable of Converting Global Normal Irradiance into Electricity." Decisive is that his module not only uses the direct sunlight that is concentrated by lenses onto the miniature concentrator solar cells no bigger than several millimeters in size, but also the scattered light and diffuse radiation. This allows the module to achieve conversion efficiencies (with respect to global normal irradiance) that are unparalleled worldwide. Up to 36.8% module efficiency has already been measured on the roof of Fraunhofer ISE, and the development continues.
"We are honored to receive this award," says Dr. Frank Dimroth, Department Head of III-V Photovoltaics and Concentrator Technology. "The EyeCon PV module provides the opportunity to implement our high efficiency concentrator technology also in countries where the sun is not always shining directly. This expands the market for these types of PV systems, which provide the highest yield per unit area today."
For over 20 years, Fraunhofer ISE has been developing concentrator photovoltaic (CPV) technology. Concentrating the direct sunlight by a factor of 200-1000, lenses or mirrors are used to redirect the light on particularly efficient III-V semiconductor solar cells that cover only a small area of the module. The modules are mounted onto tracking systems which ensure the solar cell is always in the optical focus. Up to now, CPV systems were economically attractive only in countries with a high percentage of direct solar radiation, for example, in Chile or South Africa. This new module technology widens the application to regions, for example, in Europe where diffuse light makes up 20 to 30% of the incident radiation. This light is converted into electricity using a silicon solar cell that simultaneously functions as a cooling element for the III-V concentrator solar cell. The combination of Si and III-V technology enables the very high conversion efficiencies to be reached on the module level. Before the module becomes commercially available, however, many technological challenges must be overcome and the costs must be further reduced. It is necessary that these systems track the sun with high precision. Therefore, these modules are not suitable for house roofs, but rather are primarily intended for open spaces.