Service of cracked photovoltaic panels

Why do we have the cracking of large bifacial photovoltaic panels on photovoltaic farms in Poland?

Cracking of photovoltaic panels, especially large and bifacial ones, is an increasingly common problem on photovoltaic farms in Poland. This phenomenon has a multifactorial origin, influenced by both technological aspects and environmental conditions. In this article, we will analyze the causes of cracking in the glass used in the panels, focusing on key factors such as the type of glass, mounting structures, weather conditions, ground micro vibrations and manufacturing defects.

Overview of the construction of the photovoltaic panel with its components that affect its strength

The construction of a photovoltaic panel is the result of advanced engineering aimed at ensuring not only maximum energy efficiency, but also adequate durability. Each component of a photovoltaic panel performs a specific function and affects its overall durability. Below are the main components of the panel and their importance to the durability of the structure.

1. front tempered glass. Service of cracked photovoltaic panels.

Feature: The front layer of the photovoltaic panel is tempered glass, which protects the photovoltaic cells from external factors such as hail, wind, and mechanical loads.

Properties:

Mechanical resistance: the tempering process makes the glass more resistant to impact and pressure compared to ordinary glass.
Light Transmittance: tempered glass has a high light transmission rate, allowing solar radiation to reach the cells efficiently.
Brittle damage: Despite its strength, glass is susceptible to fracture when subjected to severe point stresses.

Impact on durability: tempered glass provides protection for the cells, but its durability depends on the thickness and proper support of the structure.

2. photovoltaic cells

Function: cells are the basic component of the panel, where the conversion of solar radiation into electricity takes place.

Properties:

Fragile and thin: Made of silicon, the cells are very fragile and need to be protected by other layers of the panel.
Impact of microcracks: Even minor structural damage in cells can affect their performance and durability.

Impact on durability: Damage to cells can lead to a drop in the performance of the entire panel, making their protection a priority.

3. EVA (ethylene-vinyl-acetate) film. Service of cracked photovoltaic panels.

Feature: EVA film surrounds the photovoltaic cells on both sides, providing stability and protection from moisture and vibration.

Properties:

Flexibility: the material compensates for mechanical and thermal stresses.
Durability: EVA film is resistant to degradation by UV radiation and high temperatures, but its quality may vary from manufacturer to manufacturer.

Impact on durability: A good-quality EVA film provides protection for the cells from microcracks and moisture, which has a significant measure of impact on the life of the panel.

4 Rear glass or sintered glass

Function: The back layer of the panel protects the cells from underneath, and in bifacial models allows absorption of reflected radiation.

Properties:

Moisture and chemical resistance: glass sinter is resistant to the elements, but thinner than tempered glass, making it more susceptible to stress.
Effect of mechanical stress: The back glass or sinter can crack due to stresses generated by the panel structure.

Impact on durability: Glass sinter provides a lightweight panel, but requires sturdy frames and support structure to minimize the risk of damage.

5 Aluminum frame. Service of cracked photovoltaic panels.

Function: the aluminum frame reinforces the entire structure of the panel and allows it to be mounted on a support structure.

Properties:

Lightweight and strong: Aluminum combines light weight with good corrosion and weather resistance.
Thin profiles: Today’s frames are getting thinner, reducing their ability to compensate for stress.

Impact on strength: A frame that is too thin can lead to panel deformation under wind or snow loads, increasing the risk of glass damage.

6. protective layer (backsheet)

Function: In the case of monofacial panels, the back protective layer protects the entire structure from moisture and other external factors.

Properties:

Weather resistance: the backsheet material is UV resistant, but can degrade over time.

Impact on durability: A damaged protective layer can lead to moisture ingress and gradual degradation of the cells and EVA film.

7. connectors and wiring. Service of cracked photovoltaic panels.

Function: electrical connectors link the cells into a homogeneous system, providing current flow to the inverter.

Properties:

Corrosion resistance: Wiring must be properly insulated to prevent damage.
Resistance to changing conditions: The connectors should withstand changes in temperature and humidity.

Impact on durability: Problems with connectors can lead to local overheating (hot spots) and panel damage.

The strength of a photovoltaic panel depends on every component, from the tempered glass and EVA film to the aluminum frame and wiring.

The use of high-quality materials, proper design of the structure and regular photovoltaic service are key to ensuring long and trouble-free operation. Attention to detail at the manufacturing and installation stages helps avoid many problems associated with mechanical and operational damage.

Types of glass used in photovoltaic panels. Service of cracked photovoltaic panels.

Two basic types of glass are used in photovoltaic panels: tempered glass on the front side and glass sinter on the back side. Both materials perform different functions and have different properties.

Tempered glass:
- It is located on the front of the panel, protecting the photovoltaic cells from mechanical damage and weather conditions.
- It is transparent and has a high light transmission rate, which maximizes energy efficiency.
- Hardening increases its impact strength, but it remains brittle under point stresses.
Glass sinter:
- Used on the back side of the panel, especially in bifacial models that absorb radiation from both sides.
- It is characterized by resistance to moisture, chemicals and temperature changes, but is more susceptible to mechanical damage than tempered glass.
- It is thinner and lighter, which reduces the weight of the panel, but also reduces its ability to withstand stress.

Both types of glass, although properly selected for their functions, are subject to complex factors that cause them to break in the case of bifacial panels.

Thinner and thinner aluminum frames. Service of cracked photovoltaic panels.

Today’s photovoltaic panels are designed to optimize cost and performance. One element of this optimization is the use of thinner aluminum frames, which, however, reduce the overall rigidity of the panel structure.

Less rigid frames
- Thinner frames are more easily deformed by mechanical loads such as wind, snow or vibration.
- As a result, mechanical stresses are transferred to the glass, especially to the glass sinter at the back, which can lead to cracking.
Problems with installation
- Frames that are inadequate for the size of the panels and their thermal expansion cause additional stress points. Even minor deformations can cause micro-cracks in the glass.

Working photovoltaic structures

Support structures on photovoltaic farms in Poland, especially in areas exposed to strong winds, are often designed with materials with limited flexibility.

Construction movements
- Structures “work,” that is, they deform under wind and dynamic loads. Such movements can generate stresses that are transferred to the panels.
- With prolonged exposure to such stresses, panel materials, including glass, become more susceptible to cracking.
No shock absorption
- Many support structures are not equipped with vibration-absorbing systems. Micro-vibrations cause gradual weakening of the glass and frame structure.

Weather conditions. Service of cracked photovoltaic panels.

Poland has a variable climate, which has a significant impact on the durability of photovoltaic panels.

Extreme temperature changes
- Photovoltaic panels are exposed to extreme temperature changes on a daily basis, especially during winter mornings or summer heat. The temperature difference between the front and back of the panel leads to thermal stress, especially in the sintered glass.
Hail and snow load
- Hailstorms and snow loads pose a direct threat to the durability of glass. Lingering snow causes long-term stresses, and hailstones can cause microcracks.

Micro ground vibrations

Micro ground vibrations are another often underestimated factor affecting the durability of photovoltaic panels.

Impact on construction and panels
- Vibrations caused by ground movements, heavy agricultural or transportation equipment can weaken the structures of the panels, leading to microcracking and slow degradation of the glass.
Increased intensity in some areas
- In areas with loose soil or near highways, vibrations can be particularly intense, leading to faster wear and tear on materials.

Manufacturing defects. Service of cracked photovoltaic panels.

Also not to be overlooked are manufacturing defects that often go unnoticed during factory inspection.

Micro cracks formed in production
- When glass is cut and laminated, microcracks can form, and they enlarge over time due to mechanical or thermal stresses.
Imperfections in lamination
- Improperly applied lamination film can cause uneven stress distribution on the panel surface.

How to minimize the risk of cracking photovoltaic panels?

Selecting the right components:
- Using thicker and more durable glass and aluminum frames.
- Designing panels to withstand local weather conditions.
Proper installation:
- Attention to the uniformity of support of the structure.
- Consider thermal expansion in the design of frames and support structures.
Regular photovoltaic service:
- Inspection of panels to detect microcracks and potential defects.
- Cleaning the panels and removing accumulated snow to reduce loads.
Quality control during production:
- Introduce rigorous testing at the production and delivery stages.

The role of O&M service in detecting cracks in photovoltaic panels

Photovoltaic service, also known as O&M (Operation & Maintenance), plays a key role in managing and maintaining photovoltaic farms. One of the most important tasks of the service is to detect damage, including cracks in photovoltaic panels, and take appropriate action to minimize energy and financial losses. Expert analysis, negotiations with insurers and panel manufacturers are just some of the areas in which the photovoltaic service plays an indispensable role.

1. crack detection and technical inspection

Cracks in photovoltaic panels can occur due to a number of factors, such as mechanical loads, changing weather conditions, manufacturing defects or improper installation. The O&M service deals with the detection of such damage by:

Regular visual inspections:
- Service technicians regularly inspect the condition of the panels for visible damage, such as cracks, delamination or opacity of the glass.
Use of thermal imaging cameras:
- Cracks in the panels often reduce current flow, resulting in localized overheating (hot spots). Thermal imaging cameras can quickly locate such spots.
Electroluminescent (EL) diagnostics:
- EL is an advanced method for detecting microcracks in cells that cannot be seen with the naked eye. This diagnostic allows precise assessment of the technical condition of the panels.
Performance monitoring:
- The monitoring software allows the service to detect drops in the power generated by the panels, which may indicate mechanical damage or other problems.

2 Expert reports and technical reports. Service of cracked photovoltaic panels.

If cracks are detected, the O&M service is responsible for preparing detailed technical reports, which are the basis for further action.

Analysis of the causes of damage:
- Service technicians determine whether the cracks are due to manufacturing errors, improper installation, or external factors such as hail or wind.
Assessing the extent of damage:
- Expert reports include an assessment of whether damaged panels affect the overall performance of the farm and the cost of replacing them.
Recommendations for repairs:
- Based on the reports, the service proposes specific corrective actions, such as replacing panels, securing damaged areas or implementing additional protective solutions.

3. negotiations with insurers and manufacturers

Cracks in photovoltaic panels often become the basis for claims against the manufacturer or insurer. The O&M service supports farm owners in negotiations by acting as a mediator and technical expert.

Cooperation with manufacturers:
- If factory defects are found, the service contacts the manufacturer to enforce the warranty. Sometimes this requires the presentation of detailed technical documentation and negotiation of terms for the replacement of damaged panels.
Insurance Claims:
- Damage caused by atmospheric agents, such as hailstorms, may be covered by insurance. The service prepares expert reports and reports necessary for filing a claim and supports the client in the process of obtaining compensation.
Cost optimization:
- Thanks to its experience, the service negotiates the terms of panel replacement so as to minimize costs for the investor.

4 Prevention of further damage. Service of cracked photovoltaic panels.

Detecting cracks means not only repairing current problems, but also implementing preventive measures.

Structural monitoring:
- The service can install systems that monitor the stresses of the substructures, allowing it to detect potential problems earlier.
Adjusting the design:
- Based on the analysis, the service recommends reinforcements or changes to the substructure to minimize the risk of future damage.
Maintenance optimization:
- Regular cleaning of the panels and removal of dirt reduces the risk of microcracks caused by dust or other factors.