Concentrated photovoltaics (CPV) use optical elements to focus solar irradiance onto high-efficiency photovoltaic (PV) cells, thereby reducing the required semiconductor area while increasing overall power conversion efficiency. Researchers at the Fraunhofer Institute for Solar Energy Systems (Fraunhofer ISE) in Freiburg, Germany, have recently developed a novel micro-concentrated photovoltaic (micro-CPV) module that achieves higher efficiency and reduced production costs compared to conventional designs.
Technical challenges in prior micro-CPV architectures
Traditional micro-CPV systems have been limited by multiple degradation pathways, including optical element discoloration and long-term mechanical instability. Many existing implementations also require active thermal management due to elevated junction temperatures under concentrated light, increasing system complexity and cost.
The Fraunhofer ISE prototype consists of a 200 cm2 sub-module arranged in a 10 x 6 cell matrix. Unlike previous CPV designs that demanded precision assembly and custom optical components, the new system emphasises low-cost, scalable manufacturing techniques:
• Substrate and interconnects: Glass substrates are used for the printed circuit boards, providing mechanical stability, thermal compatibility, and efficient heat spreading.
• Assembly method: Standard high-speed pick-and-place machines can mount the photovoltaic chips, enabling compatibility with existing electronics and display industry manufacturing lines.
• Optical concentration: The focusing optics employ planoconvex silicone-on-glass lenses. Silicone provides sufficient refractive properties at low cost, while the glass base ensures matched thermal expansion coefficients. This maintains optical alignment under varying environmental conditions.
The researchers report that the design requires less than 0,1% of the semiconductor material typically consumed by conventional flat-panel PV systems, representing a substantial reduction in critical material demand.
Performance results
The prototype was tested under concentrator standard test conditions and during a year-long outdoor deployment with the following recorded:
• Peak conversion efficiency: 36%.
• Outdoor median efficiency: 31,4–33,6% across varying irradiance, ambient temperature, and windspeed conditions.
• Durability: No significant optical or electrical degradation observed after 12 months of operation.
For comparison, state-of-the-art commercial crystalline silicon panels typically achieve 19–24% efficiency, indicating that the micro-CPV module delivers ~50% higher energy yield per unit area.
Outlook
The demonstrated Fraunhofer ISE micro-CPV design represents a significant advance in high-efficiency, low-material-use photovoltaics. With efficiencies exceeding 30% under real-world conditions and compatibility with high-volume manufacturing processes, the technology has strong potential for utility-scale deployment.
For more information visit https://ise.fraunhofer.de
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