IV-Measurements of Bifacial Solar Cells in an Inline Solar Simulator with Double-Sided Illumination
Bifacial solar cells allow higher output power densities due to double-sided power generation compared to monofacial cells. An important step is the accurate measurement of the current-voltage (IV) characteristics of the cells under realistic conditions. The most accurate option to measure a bifacial solar cell is to illuminate the cells simultaneously from both sides. A new method for irradiance and short-circuit current correction for bifacial solar cells suitable for inline measurements in mass production is presented, where the crosstalk during a single-sided measurement and deviations of the ratio of the nominal to the measured irradiance at double-sided illumination measurements will be corrected by taking the bifaciality coefficient into account. This reduces typical measurement errors for the short-circuit current Isc below 0.1%. The simple approach, adding the front and the rear side irradiance directly to calculate the bifacial irradiance, shows Isc errors of more than 0.5% in typical measuring conditions and should not be used when the solar cell is double-sided illuminated.