NATURAL RECOVERY FROM LID: REGENERATION UNDER FIELD CONDITIONS?

摘要

Photovoltaic modules made from silicon PERC solar cells were installed outdoors for a study of their light-induced degradation (LID). The modules left in open circuit showed rapid LID in the first two weeks, but then recovered to above 98% of their initial output power in the following five weeks. In contrast, the modules that were maximum-power-point (MPP)-tracked did not show any sign of recovery within the test period, resulting in LID of 4-6%. The field results are in agreement with the cell regeneration experiments that showed the excess carrier density to be a crucial factor in determining the regeneration rate. The modules made from regenerated PERC cells were also MPP-tracked in the field, and they showed LID of about 2%. The LID resistance of PERC modules could be further improved by integrating the regeneration process into the lamination step. As the lamination is the last high-temperature step in the module production, any subsequent destabilization of the deactivated BO defects can be avoided with the Regenerating Lamination. The PERC modules made with Regenerating Lamination showed LID below 1%.