A novel parallel interconnection approach to reduce shading losses on submillimeter concentrated photovoltaic technologies

Concentrated photovoltaics (CPV) provides the highest efficiency among photovoltaic technologies but remains too expensive to be deployed on a large scale. The miniaturization of this technology (micro-CPV) appears to be one of the most promising paths toward CPV competitiveness, but the reduction in cell size poses important packaging challenges. With a greater number of cells to be interconnected, the sequential nature of traditional wire bonding becomes untenable, favoring a parallel interconnection method. Furthermore, the large contact pads (busbars) required for wire bonding (~100µm) represent a significant proportion of inactive region (shading) in these submillimeter cells, resulting in significant material losses. In this paper, a new method of interconnection for micro-CPV cells is proposed. The process allows for the parallel interconnection of hundreds of solar cells while reducing the required size of the busbars on the cells and, consequently, shading losses. A solar cell of 0.25mm 2 achieving 30% efficiency after this interconnection process is presented and its increase in performance due to reduced shading is demonstrated. Finally, calculations are provided to support a savings of 8 % in material usage compared to traditional wire bonding for a solar cell of 0.25 mm 2 , owing to the smaller busbars, with projections to further increase savings to 13 %.