Influence of metal grid spacing on the conversion efficiency of concentration solar cell at different illumination levels

The design of front metal grid spacing of linear grid pattern for III-V multi-junction concentrated solar cells is a critical issue when high density photocurrent is induced under concentrated sunlight and a poor grid spacing results in resistive losses. In the present work we have performed outdoor experiment and investigated both theoretically and experimentally the effect of ten different metal grid spacing on the electrical performance of high efficiency GaInP/GaInAs/Ge concentrated solar cells under various concentrating level of sunlight. The shadowing ratio of metal grids was adjusted from 3.07% to 6.66%. We have observed that the variation of experimentally obtained variation of power conversion efficiency data with grid spacing is consistent with the variation of theoretical estimation of total power loss with grid spacing. Moreover, the total power loss was dominated by grid shadowing effect at lower concentration levels; while at higher concentration levels the lowest total power loss condition was found when a compromise occurred mainly between grid shadowing effect and resistance of metal lines.