Concentrating and spectrum splitting optical device in high efficiency CPV module with five bandgaps

Abstract

There is a need for a high efficiency low cost solar energy conversion system. Currently, most concentrating photovoltaic (CPV) systems concentrate the solar spectrum onto triple junction cells to strive for high conversion efficiencies and low cost. Other approaches to high efficiency use spectrum splitting. Triple junction systems are limited in efficiency and spectrum splitting systems are usually too costly for mass production. The objective is to design a spectrum splitting solar concentrator, using reverse ray tracing methods, to overcome the efficiency and cost limitations of current systems by using a single low cost optical device to concentrate and split the solar spectrum onto a large number of target photovoltaic (PV) cells. Dispersive properties of standard optical materials, such as glass or plastic, are utilized to achieve the desired spectral separation. Reverse ray tracing is used to simultaneously optimize the shape of the top and bottom interfaces of the solar concentrator to achieve the desired split spectrum at the target PV cells. Additional strategies to increase system efficiency and minimize optical losses, including draft surface shading and corner rounding losses, are explored. A CPV module, including the spectrum splitting solar concentrator and five PV cells of different bandgaps, is proposed. This spectrum splitting CPV system has a calculated aggregate cell conversion efficiency that exceeds 45%, has the potential to be mass produced, and meets the need for a high efficiency low cost solar energy conversion system.

Adaptation of the Solar Spectrum to Improve the use of Sunlight: A Critical Review on Techniques, Applications, and Current Trends

“…However, this study was only theoretical. Likewise, Taudien and Kern [ 36 ] suggested using a concentration beam splitting with five different PV cells, each with different bandgaps, by a reverse ray‐tracing method. This system had a total conversion efficiency of 45% and an optical efficiency of 93%.…”

A Review on Recent Development of Cooling Technologies for Concentrated Photovoltaics (CPV) Systems

“…Currently, the majority of Concentrator photovoltaics systems use triple junction cells to achieve higher photoelectric conversion efficiency and lower cost. But the triple junction cell has a limited efficiency, and though the spectral beam splitting system can realise high theoretical conversion efficiency it is too costly for mass production [38].…”

“…A novel spectrum splitting CPV system has been invented by Jaker et al in 2013 [38]. In this system, single and low-cost optical materials with dispersive properties, such glass and plastic, are selected to produce the desired spectral separation.…”