Effects of encapsulation on the performance of silicon solar cells

An optical model which can predict the performance of an encapsulated cell, in a flat-plate module, from the cell data measured in air is described. This model is applicable to planar as well as rough or textured cells and includes the effects of light trapping between the cell and the glass-air surface due to optical scattering by the cell, metallization, and intercell gap. Application of this theory to standard module configuration shows that changes in the cell performance due to encapsulation depend strongly on the characteristics of the antireflection (AR) coating of the cell. The cell performance can increase upon encapsulation if the thickness of the AR coating deviates significantly from an optimum value. Experimental results from comparing the performance of polycrystalline silicon cells before and after encapsulation are in excellent agreement with the theory. The theory can be applied to design AR coatings for optimized module performance