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Hotspot Effect: Causes, Ways to Mitigate & Panels with Less Impacts

The hotspot effect is a phenomenon that occurs in everyday usage of solar panels. This effect can impact both the panels and the solar generation system as a whole. Hence, it is crucial to understand its origins and ways to mitigate for a smooth and efficient operation of the system.

Keep reading; mastering this subject can get the best value for your equipment and build trust during sales interactions.

What Is the Hotspot Effect on Solar Panels? What Causes It?

The name vividly portrays its definition.

The hotspot effect refers to localized areas of overheating on the surface of individual solar cells within a solar panel. This phenomenon occurs when certain cells in a panel generate less electricity than other cells, leading to an imbalanced circuit of the panel. 

Inside the imbalanced circuit, typically in series connection, the underperforming cells become ‘reverse-biased’, which dissipate part of the energy from adjacent cells as heat instead of converting it into electricity.

Inspecting Hotspots On Solar Panels Using Thermal Imaging Camera

Below are several factors contribute to the formation of hotspots on solar panels:

  • Shading: This is a very common cause. Objects like trees, buildings or other tall structures can cast shadows on parts of a panel. This results in lower generation in shaded cells, then the hotspots.
  • Accumulation of Dirt and Dust: When various residues accumulate on the surface of solar panels and block sunlight from reaching the cells, the cells would function inefficiently, leading to increased temperature and hotspot formation.
  • Material & Manufacturing Defects: If there are deviations in the manufacturing materials of the cells and imperfections during the manufacturing process such as poor soldering, hotspot effect can occur.
  • Poor Cooling Design & Extreme Weather: A solar power system should be integrated with proper ventilation or cooling mechanisms to maintain an appropriate ambient temperature for the efficient operation of the panels. Poor cooling design when accompanied with extreme weather, e.g., ‘hotweaves’, can exacerbate the formation of hotspots.

What Are the Impacts of the Hotspot Effect?

The consequences of the hotspot effect on solar panels are multifaceted.

  • Reduced Efficiency & Output: Following the working principle of series connections, hotspots can straightforwardly significantly lower the efficiency and output of the solar panel, as the performance of the panel is impacted by the affected cells. From a broader perspective, the affected cells and panels will subsequently influence the performance of the system, especially if not equipped with optimizers or microinverters.
  • Physical Damage: It is not only a cause of hotspot effect, but also an impact of the effect itself. Prolonged exposure to high heat can lead to physical damage to the cells and the panel structure, including the melting of solder and cracking of the protective glass. In certain cases, it could induce permanent faults in the panel.
  • Accelerated Aging: The higher temperature caused by hotspots can result in a faster degradation of the materials of the cells and panels. For example, the polymer used in the encapsulation layer or the silicon in the cells can degrade faster.
  • Safety for People and Properties: Similar to the thermal runaway in the batteries of solar street lights outdoors, hotspot effect can uphold localized temperature to more than 100°C and give rise to severe safety hazards such as fires, posing a risk not only to nearby people, but to the assets and properties.
Imaging of Hotspots on Solar Cell
Wang, A., & Xuan, Y. (2021). Close examination of localized hot spots within photovoltaic modules. Energy Conversion and Management, 234, 113959.

What Are the Ways to Mitigate the Hotspot Effect?

In order to mitigate the hotspot effect and minimize losses, several strategies can be employed, explained as follows:

  • Using Panels With Bypass Diodes: Beyond sourcing panels that are crafted with quality materials and consistent manufacturing techniques, make sure the products are designed with bypass diodes, which are electric devices that in conjunction with different groups of cells within a panel. They can help reduce the risk of hotspot effect by allowing the electricity to bypass the shaded or affected cells.
  • Proper Design and Installation: A solar generation system with proper design and installation sees to it that the panels are exposed to maximum amount of sunlight with less shading. Moreover, proper ventilation with adequate airflow can diminish the severity of the hotspot effect if it occurs.
  • Regular Maintenance: Cleaning solar panels with cleaning kits or robots regularly can remove the accumulation of dirt, dust or droppings in time can prevent hotspot formation.
  • Accurate Monitoring: Thermal imaging using drones is an accurate and direct means to spot and locate potential hotspots on solar panels. While effective, this service might not be promptly available in some regions. However, handheld thermal imaging cameras can offer you a basic sense of potential hotspots. They typically cost around $100-300. Another indirect means to troubleshoot potentially affected panels is leveraging the data provided by optimizers or microinverters attached to the panels.

Are There Any Panels That Come with Less Hotspot Effect?

Due to the nature of electric circuits, the hotspot effect is a common issue on solar panels. But there are indeed some kinds of panel products that come with less effect, preserving a more stable efficiency and output.

Shinged Solar Panels

In addition to showcase a more aesthetically appealing look, shingled solar panels are also well-known for their premium design that has cells cut into strips and overlapped like shingles, allowing for a more flexible flow of electricity and reduced impact of hotspot effect on overall performance.

Half-Cut Solar Panel Technology

Somehow similar to the concept of shingled solar panels, by splitting the traditional crystalline solar cell in half, half-cut solar panels decrease latent resistance caused by hotspots within the panel. Consequently, the impact on the panel’s overall performance is minimized.

Solar Panels With Improved Anti-Reflective Coatings

Adopting anti-reflective coatings (ARCs) on solar panels can improve light absorption across the entire surface of the solar panel. This helps distribute the incoming sunlight more evenly and maintain a more consistent cell temperature across the panel than products without ARCs.

Wrapping Up

Comprehending the causes and impacts of the hotspot effect on solar panels builds the foundation for effective operation of your panels and system, as long as a prolonged lifespan of your equipment.

By deeply communicating the knowledge of hotspots to your clients, you can make them perceive the value of premium products more easily.

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