FROM SMALL-AREA CELL TO LARGE-AREA MODULE PERFORMANCE-ROLE OF INHOMOGENEITIES IN THIN FILM PHOTOVOLTAICS

摘要

Simulations using a two-dimensional model in PSpice have been used to examine the loss mechanisms from small-area microcells to monolithically integrated solar cells and whole thin-film modules. The study is based on CIGS cells and modules, starting with loss analysis in the homogeneous cell made of the baseline microcells. The conversion efficiency strongly depends on the sheet resistance of front transparent conductive oxide and monolithic contact area losses. Performance of cells with a single deteriorated microcell depends primarily on the type of defect and its strength. A shunted microcell almost linearly decreases the subcell's efficiency with the increase of shunt's conductivity, while a weak-diode/low-V_(oc) microcell does not affect the performance until a voltage-decrease treshhold of 200 mV is exceeded. For lower-voltage weak-diodes, efficiency decreases significantly. Distribution of weak-diode microcells only slightly affects the cell's efficiency, while the distribution of shunts affects it more strongly.