An efficient circular contact grid for concentrator solar cells

Abstract Efficient circular contact grids are developed for solar cells intended for work at high levels of concentrated sunlight. The cell efficiency is studied as a function of grid design, concentration ratio and cell radius. It was found that there is a trade-off between the maximum cell efficiency and the decay in the efficiency as a function of concentration. For Al x Ga 1− x As-GaAs cells 15 mm in diameter a high efficiency may be achieved even at a concentration of over 300-fold with a shading loss as low as 5%. For a concentration of 800 suns, good results may be obtained at about 10% shading. At 800 suns, doubling the cell diameter from 1 to 2 cm accounts for less than a 2% loss in cell efficiency, and this loss in efficiency is primarily related to the power loss due to increased current flow through the grid towards the outer collector.