Panels with Hotspots
Hot spots are sections within the panel that are overheating. These typically occur due to bad soldering or poor assembly from the manufacturer. A connection that is not soldered correctly causes low resistance by the cell receiving the power. The outcome results in voltage rising and hotspots occurring in cells and soldered points. This would then shorten the lifespan of the panel, reducing performance, and more than likely shorten the circuit at hand.
Micro cracks are tiny tears within the solar cells. This may occur from poor use of the panels. Mishandling panels could occur from installation, packing/shipping, or manufacturing assembly. The issues associated with micro-cracks would not typically happen instantly but over time these cracks can grow. These growths that could occur would typically happen due to continuous misuse of the panels or due to fluctuating temperatures from the different seasons and weather conditions, known as thermal tension. Larger micro-cracks will damage the solar cells, and this will lead to production loss.
Potential Induced Degradation (PID)
This can happen when a voltage difference occurs between the panel and the grounding. For safety precautions, the solar panel is grounded, which can cause a potential harmful difference between the grounding and the voltage generated by the panel. In some cases, this generates a voltage that can be partially discharged in the primary power circuit. The consequences of this effect are poor performance and a quick way to kill the lifespan of a system.
Internal corrosion, or rusting occurs, when moisture gets into the panel. Panels must be air- and water-tight. In order to achieve this, the glass layer, the solar cells and the back sheet, are laminated under vacuum. If the lamination process isn’t done properly or becomes too short, this can lead to a delamination during operation. Delamination is the detachment of the laminated parts. Delamination – but also incorrectly fitted module trim, for example – can cause moisture to penetrate or bubbles to occur. Moisture leads to corrosion, which becomes seen as darker spots on the panel.
This often starts at the edge of the panel and can spread across the rest of the panel. Corrosion on the metal portion of the panel will then lead to reduction in the panel’s production. Frameless/thin-film PV panels and panels manufactured based on glass substrates in particular can also suffer from moisture and corrosion problems.
Over time, bird nests, droppings, and debris can cause quite a bit of damage to solar panels. When birds build nests under solar panels, they attract other pests, such as squirrels and rodents. The nests itself can reduce the performance of some panels. These critters overall, tend to chew through the solar panel's electrical wiring, which would then lead to short circuits and on some rare occasions, rooftop fires. Aside from those worst case scenarios, low performance within the system would come first if a short circuit had not already taken place.