Effect of encapsulant on cell-to-module efficiency loss in PV modules with ion implant and POCl3 cells

This paper presents work assessing the cell-to-module (CTM) efficiency loss of ion implant (IMP) cells in comparison with POCl₃ (POCl) diffusion cells, using both standard EVA and silicone encapsulants. In order to reduce uncertainty in CTM loss analysis, single cell test modules with different encapsulants were fabricated using an established lamination process. 10 test modules were prepared for each cell and encapsulant category to ensure statistical accuracy. The I-V characteristics were measured on bare cells, tabbed cells, and modules using class AAA solar simulators. Specifically, a shading mask was applied to the front of modules during I-V measurement to mitigate the backsheet effect. Moreover, the statistical significance of the measured CTM loss was determined. The analysis showed that the effect of encapsulant (silicone versus EVA) on relative short-circuit current (I_sc) loss was statistically significant, whereas the effect of cell type (IMP versus POCl) was not significant at the 95% confidence level. In addition, the CTM loss in absolute efficiency for modules with IMP cells is about 0.1% higher than those with POCl cells. The experimental results agree well with optical model predictions.