An Investigation of Impacts of Shading on PV Module Temperature and Performance

The performance and efficiency of photovoltaic (PV) solar panels are increasingly important in enabling a rapid energy transition away from fossil fuels as the effects of climate change continue to worsen. Shading on PV panels is known to cause reduced power output because of the decreased energy hitting the cells for conversion to electricity. Additionally, power losses can occur from the reduced current through the entire panel, inducing cell mismatch and possible hotspots among the shaded cells. Experiments were conducted to explore these effects; shading of one cell was induced on one of two identical 50 W solar panels set under the same conditions while the power output and temperature distribution of the panels were recorded. The shaded panel had a significantly lower power output than the unshaded panel and a higher overall temperature. Additional experiments were conducted on an experimental module where nine 1V solar cells were wired in series, and the current and temperature of the cells were measured under varying shading conditions. As anticipated, the higher intensity shading resulted in lower current over the entire module and a voltage drop across the shaded cell, indicating that cell mismatch occurred and power was being dissipated into the cell. Lastly, the performance of the PV module and individual shaded cells were measured to see if lasting degradation occurred after the sustained shading experiments.