Hotspots are localized temperature increases in solar panels that can seriously impact their performance. They occur when there’s a problem with one of the connections between photovoltaic cells, causing increased resistance and a rise in potential difference. This issue affects the entire string of cells connected in series.
These temperature spikes can lead to a dangerous situation where the solar panel can even catch fire, as the current approaches the short-circuit current. In essence, hotspots are areas of high temperature that harm solar cells, consuming energy instead of generating it. This significantly reduces the efficiency of the entire solar panel during electricity generation.
Why Do Hotspots Occur?
Hotspots typically occur when a solar panel is shaded, preventing the current from flowing properly around weaker cells. Instead, the current becomes concentrated in these cells, causing them to overheat and potentially melt. Solar panels are constructed from semiconductor materials that convert light energy into electricity. When a bad cell limits the current in a series, the excess current generated by the good cells heats up the weak one. If the series of cells is short-circuited, it results in a high reverse polarization in the shaded cell, leading to substantial power dissipation and overheating.
Since solar cells are connected in series, if even one cell or group of cells doesn’t receive enough light, it affects the energy production of all cells in the same string. This issue not only reduces overall energy efficiency but also accelerates material degradation. Hotspots tend to worsen over time and can eventually cause the panel to completely fail in terms of electrical output and insulation.
Also See: What is PID (Potential Induced Degradation)?
How Can I Know if My Plant has Hotspots?
The best way is to use thermography to measure the temperature of each module’s surface. This will give you thermal images showing the temperature of all modules and help you spot any hotspots.
How to Avoid Hotspots
This problem is often not visible unless there’s a clear color difference, like a brownish spot on the solar module.
When hotspots already exist on solar modules, little can be done because the cells will degrade and potentially damage the module. The solution often involves buying a new module, but there are steps to prevent hotspots:
1. Invest in quality: Buy from a certified company known for quality products. Their service is more specialized, and they use high-quality materials for optimal thermal properties. Follow the manufacturer’s instructions for your solar modules to maximize performance.
2. Maintain good airflow: Hotspots result from heat buildup, and poor airflow increases this risk. A good solar panel system ensures proper ventilation to prevent overheating.
3. Use a solar tracking system: These systems move panels to follow the sun, reducing hotspots by always exposing panels to direct sunlight. However, they can be expensive and increase electricity production costs due to added moving parts.
4. Install panels at the right angle: Consider the surroundings and solar exposure to determine the best angle for panel placement. Avoid obstructions like buildings or trees that create shade. Work with specialized installers to find the best setup.
5. Regular panel cleaning and maintenance: Dirt and contaminants on panels block sunlight and generate heat spots. Cleaning your panels regularly prevents this issue, reducing its impact.
Recommended: What is Solar Panel Degradation?
