Micro Cracks in Solar Panels: Causes, Impacts, and Prevention

Micro Cracks in Solar Panels: Causes, Impacts, and Prevention

Micro Cracks in PV (solar) panels are tiny, often imperceptible fractures that can significantly impact the performance and durability of  the panels. These cracks are a concern in the solar industry due to their ability to propagate and degrade PV panels over the time, potentially reducing power generation and increasing maintenance costs. Understanding their causes and effects is essential for manufacturers, installers, and solar energy users.

What Are Micro Cracks?

Micro cracks are small fractures in the silicon cells of solar panels. They typically measure in micrometers, making them invisible to the naked eye, yet they can affect the structural and electrical integrity of solar panels. These cracks can form during manufacturing, transportation, installation, or operational use.

Causes of Micro Cracks

  1. Manufacturing Defects:
    • Flaws during wafer production or module assembly can introduce weak points. Poor quality control may fail to detect such defects.
  1. Mechanical Stress:
    • Improper handling during transportation or installation can lead to stress on the panels, causing cracks. Dropping or bending the panel increases the risk cracks can arise in a panel.
  1. Environmental Stress:
    • Extreme weather conditions like hailstorms, strong winds (bending big panels), or temperature fluctuations introduce thermal expansion and contraction, which is leading to cracking.
  1. Operational Wear:
    • Continuous exposure to environmental elements, combined with electrical load cycling, can cause micro cracks to propagate over time.

Impacts of Micro Cracks

  1. Reduced Efficiency:
    • Micro cracks interrupt the flow of electricity in silicon cells, lowering the panel’s efficiency. Broken cell connections (to busbar’s, which collect the generated power in the PV panel) lead to increased resistance and reduced power output.
  1. Hot Spots Formation:
    • Cracked areas may cease to generate electricity but continue to heat up under sunlight, creating hot spots. That can damage the panel further.
  1. Accelerated Degradation:
    • Cracks allow moisture ingress and increase susceptibility to environmental stress, accelerating the aging process of the panel.
  1. Shortened Lifespan:
    • Over time, the accumulation and expansion of micro cracks can render a solar panel inoperable, well before its expected life span of 20–25 years.

Detection of Micro Cracks

Advanced diagnostic tools are required to identify micro cracks in solar panels. Common methods include:

  1. Electroluminescence (EL) Imaging:
    • This technique reveals internal defects by capturing an image of the panel while it is electrically stimulated.
  1. Infrared (IR) Thermography:
    • Identifies hot spots caused by micro cracks during operation.
  1. Visual Inspection with Magnification Tools:
    • Helps in detecting surface-level defects that might indicate deeper cracks.

Preventing Micro Cracks

  1. Improved Manufacturing Standards:
    • Investing in quality materials and advanced manufacturing techniques can reduce the initial formation of cracks.
  1. Careful Handling and Installation:
    • Transport panels in protective packaging, and avoid rough handling or bending during installation.
  1. Design Enhancements:
    • For stand alone panels use flexible materials and reinforced glass to absorb mechanical and thermal stress better. For small embedded panels use a backplane and ETFE encapsulation to deal with thermal stress and mechanical impact.
  1. Regular Maintenance:
    • Conduct routine inspections for stand alone panels using diagnostic tools to detect and address micro cracks early.
  1. Environmental Considerations:
    • Install stand alone panels at optimal tilt angles and secure them against high wind speeds to minimize environmental stress.

What did Ydoc do to prevent Micro Cracks on their PV panels?

  1. Improved Manufacturing Standards:
    • We invested in quality materials and selected a manufacturer that uses advanced techniques and tests to reduce the initial formation of Micro Cracks.
  2. Careful Handling:
    • Panels are shipped in protective packaging to the Netherlands.
  3. Carefull Assembly:
    • Assembly is done in our workshop in Ede, under optimal conditions. Preventing rough handling or bending of panels.
  1. Design Enhancements:
    • Together with our PV panel Manufacturer, we designed a new panel lay-out. The size and placing of the cell’s and busbars reduces power-loss when a individual cell is suffering from micro Cracks or completely failing. With less busbars, the panel is more efficient, but less durable.

In the Ydoc workshop (located in Ede), stand alone solar powered covers are carefully assembled with PV panels.

Currently deliverance of PV panels

Over the past years, Ydoc has delivered five types of solar panels in the PV powered covers.

Only the 5th generation of stand alone PV panels is currently delivered to our customers.

From left to right: 3rd to 5th generation Solar panel for Ydoc data logger.

Quality testing

After assembling, all mounted PV panels are tested on power deliverance with a calibrated light source.

Conclusion

Micro Cracks are a significant challenge in maintaining the efficiency and reliability of PV panels. While they are often unavoidable, understanding their causes and implementing robust prevention and detection measures can mitigate their effects. As the solar industry advances, innovative materials and diagnostic technologies promise to enhance the durability and performance of PV systems, making solar energy even more sustainable and cost-effective.