How Do Microcracks in Solar Panels Affect Performance?
Apr 16, 2025| 
As the world pays more and more attention to renewable energy, solar panels are being widely used in residential, industrial, agricultural and public facilities as a clean and efficient energy conversion tool. However, during the long-term operation or transportation and installation of solar panels, a structural defect that is difficult to detect with the naked eye but poses a potential threat to performance may occur - microcracks. Although microcracks are not as obvious as macro cracks and do not directly cause equipment failure, they have an important impact on the power generation efficiency and service life of solar panels.
Microcracks refer to fine cracks that appear on the surface or inside of solar cell materials, and their size is usually in the millimeter level or even smaller. Since the main photovoltaic conversion unit of the solar panel is composed of polycrystalline silicon or monocrystalline silicon cells, these materials have good photovoltaic properties but are relatively fragile and prone to microcracks under stress.
Unlike macro cracks that are visible to the naked eye, microcracks are usually difficult to detect through ordinary visual inspection and need to be identified with the help of professional testing equipment. Microcracks are common in the middle, edge, welding point and interface between laminated materials of the cell, especially in the area of welding connection.
Although it may not cause obvious performance loss of solar panel in the early stage, these microcracks may gradually expand over time, affecting the current transmission path of the cell and even causing local thermal damage.
How do microcracks occur?
Stress problems in the manufacturing process: In the processes of slicing, welding and lamination, the thermal and mechanical stresses applied by different processes may cause local cracks in the silicon wafer. For example, due to the different thermal expansion coefficients of the welding head and the cell during welding, tensile stress is easily generated during the cooling stage.
Mechanical shock during transportation and installation: If the solar panel is impacted, vibrated or unevenly applied during transportation or handling, it is easy to cause microcracks inside the cell, especially thinner and lighter panels are more sensitive.
Fatigue stress caused by extreme climate: During long-term operation, solar panels need to face environmental challenges such as hot and cold cycles, hail impact, strong winds or snow. These climatic conditions may cause repeated cycles of thermal expansion and contraction of materials, resulting in fatigue stress and eventually microcracks.
Initial impact: Current path is blocked, local short circuit
Microcracks may cut off or block the flow path of electrons in the cell, resulting in uneven current or current detour, resulting in increased local resistance.
Medium-term impact: Increased risk of hot spot effect
In some microcrack areas, the concentrated flow of current will form a "hot spot", the local temperature will rise, and in severe cases, it may even burn the cell or welding point, affecting the overall safety of the solar panel.
Long-term impact: Continuous power decline, affecting the overall system efficiency
As microcracks expand, the number of damaged cells increases, which will lead to a decrease in output power. Studies have shown that a small microcrack may cause a 5% to 20% decrease in the efficiency of a single cell, thereby affecting the power generation performance of the entire solar panel or even the entire photovoltaic system.
How to detect microcracks in solar panels?
EL (electroluminescence) detection: EL detection is to identify the area where current transmission is blocked by shooting the electroluminescent image emitted by the cell after power is turned on in a dark environment. Microcracks usually appear as dark lines or black lines with clear distribution.
Infrared thermal imaging: By monitoring the temperature distribution on the surface of the solar panel, local temperature rise areas caused by microcracks, namely "hot spots", can be found, which is suitable for rapid on-site inspection.
Ultraviolet imaging technology: This technology indirectly reflects the structural integrity of the cell by observing the fluorescence distribution of the cell under ultraviolet light, but its ability to identify smaller microcrack areas is slightly inferior to EL detection.
Limitations of detection and advantages of laboratory detection: On-site detection is easily affected by light, temperature and environment, and there is a certain possibility of misjudgment; while laboratory detection has high accuracy and low interference, and can be used for confirmation and in-depth analysis.
Although microcracks are not conspicuous in solar panels, their impact on performance is far-reaching and cumulative. By improving material quality, standardizing manufacturing processes, optimizing transportation and installation details, and establishing an effective detection and maintenance system, the impact of microcracks on the efficiency of solar systems can be greatly reduced.