Secondary Optics Assembly for Micro Concentrating Photovoltaics: A Parallelized and Scalable Approach

Spherical Glass lenses are used as secondary optics in micro-concentrating photovoltaics (micro-CPV) to improve the acceptance angle and increase the concentration factor while at the same time being cost-efficient. They ensure that the incident light cone is focused precisely on the micro solar cell and mitigate the effects of manufacturing and alignment tolerances. In this work, we present a novel method for mounting spherical glass lenses on pre-assembled micro solar cells in a parallelized and industrially scalable process. It is based on the process of flux printing with subsequent solder balling, which is a well-established technique in electronics manufacturing. A laser-cut steel stencil with attached vacuum unit is used to place spherical optical elements in a parallelized manner. Using this technique, we manufactured a prototype micro-CPV array with an aperture area of 205.35 cm2 consisting of 6 x 10 micro solar cells equipped with spherical glass lenses. An average positioning accuracy from cell to lens of ~53 μm is achieved. These results are an important contribution towards cost-effective manufacturing of micro-CPV modules for terrestrial applications.