Is it CPV? Yes, but it is a partial CPV

• Main Authors: Araki, Kenji, Ota, Yasuyuki, Lee, Kan-Hua, Nishioka, Kensuke, Yamaguchi, Masafumi
• Format: Conference Proceeding
• Language: English
• Subjects: Concentrators; Photovoltaic cells; Solar cells; Sunlight
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/1.5001439

III-V on Si cell is one of the most promising candidates of the low-cost and high-efficiency solar cell beyond the limit of Si cells. However, it is likely that the cost of III-V cell will keep greater than that of Si cells. The partial concentrator technology was invented to concentrate the sunlight onto smaller III-V cells on the Si cell with the increased acceptance angle for static concentrator operation. The partial concentrator allows on-axis optical loss but expands the apparent acceptance angle often beyond the thermodynamic limit. The spilled light will be saved and collected by the bottom Si cell. It is not just placing the Si cell around the concentrated III-V cell, but its design philosophy is “partially” collecting the sunlight to the III-V cell to expand the acceptance. Depending on the values of cost parameters, the cost of the partial CPV module becomes minimum at 4 x – 10 x of concentration onto the top III-V cell, meaning that the area of expensive III-V cell can be saved to 1/4 – 1/10. In the partial concentrator. There may be a better optics than the ideal concentrator. The partial concentrator can be applied not only to III-V on Si cells but also III-V “by” Si cells. This lateral configuration does not have as excellent efficiency as the III-V on Si cell, but the usage of III-V cell is only several percents of the Si cell and has good similarity on the conventional Si flat-plate module technology.