Effect of Thermal Cycling Aging Photovoltaic Ribbon on the Electrical Performance of Photovoltaic Modules

The objective of this study was to reveal the impact of aging photovoltaic ribbon welding layer materials on the performance of photovoltaic modules. We conducted thermal cycling aging on photovoltaic ribbon, solar cells, and solar cells welded with photovoltaic ribbons. Using scanning electron microscopy, we observed the welded interface morphology of photovoltaic ribbon. The results show that the solder exhibited coarsening, the voids increased, and the intermetallic compound layer thickened at the welding layer. These changes can lead to a decrease of the peeling force in the welding layer, as well as a degradation in the performance of photovoltaic modules. After 200 cycles of thermal cycling aging, the peeling forces of the welded photovoltaic ribbons on the front and back of the solar cell decreased by 0.588 and 3.236 N, respectively. To verify the impact of the aging of the welding layer on the performance of photovoltaic modules, we designed experimental plans for the independent aging of photovoltaic ribbons, solar cells, and solar cells welded with photovoltaic ribbons, combined aging materials, and fabricated four types of photovoltaic modules. After 200 cycles of thermal cycling aging, the power degradation rates of the four photovoltaic modules were 5.9% (aged photovoltaic ribbons + unaged solar cells), 7.5% (unaged photovoltaic ribbons + aged solar cells), 12.5% (aged photovoltaic ribbons + aged solar cells), and 14.3% (aged solar cells welded with photovoltaic ribbons). These results reveal the relationship between the aging of photovoltaic ribbons and the power degradation of photovoltaic modules.