How Is a Mechanical Load Test Performed on PV Modules?

Solar panels Photovoltaic PV modules static dynamic mechanical load tester

Photovoltaic (PV) modules are exposed to various mechanical stresses during outdoor operation. Wind pressure, snow accumulation, and other environmental factors can place significant loads on solar panels.

A PV module mechanical load test is an important reliability test used to evaluate whether a solar panel can withstand specified mechanical loads without unacceptable damage.

So, how is a mechanical load test performed on a photovoltaic module?

The basic process involves installing the PV module on a test frame, applying specified mechanical loads to the module surface, maintaining the required load for a specified period, and inspecting the module after testing.

1. Install the PV Module

Before starting the mechanical load test, the photovoltaic module is securely installed on the test frame.

The mounting method should follow the applicable testing standard and the installation configuration specified by the module manufacturer.

The mounting configuration is important because the position of the supports and clamps can affect how mechanical stress is distributed across the module.

For different solar panel sizes, a PV Module Mechanical Load Tester may be equipped with an adjustable mounting structure to accommodate different module dimensions.

2. Set the Mechanical Load

After installing the module, the required mechanical load is set according to the applicable testing standard and the module's design requirements.

For photovoltaic module testing under IEC 61215, the static mechanical load test is identified as MQT 16.

Mechanical loading may include:

• Positive load
• Negative load

Common configurations may use 5400 Pa positive load and 2400 Pa negative load. However, the actual test load depends on the applicable standard, module design load, mounting configuration, and manufacturer's requirements.

Therefore, the required test parameters should always be confirmed before testing.

3. Apply the Mechanical Load

After the test parameters are set, the solar panel mechanical load tester applies the specified load to the PV module.

Depending on the equipment design, the loading system may use pneumatic cylinders, loading plates, suction cups, or other mechanisms to apply force to the module.

The control system regulates the loading process and monitors the applied pressure or force to help ensure stable and repeatable testing conditions.

4. Maintain the Required Load

Once the specified load has been reached, the load is maintained for the required period according to the test procedure.

A typical loading process can be described as:

Loading → Reaching the Required Load → Holding → Unloading

The procedure is then repeated according to the required test cycles.

The mechanical load test is not only concerned with the maximum pressure. Factors such as load level, loading time, loading direction, loading cycles, and module mounting configuration can all affect the test results.

5. Perform Positive and Negative Loading

Photovoltaic modules may experience mechanical forces from different directions during outdoor operation.

Positive loading can be used to simulate pressure acting on the front surface of the module, such as loads associated with snow.

Negative loading can simulate suction forces acting on the module, such as those caused by wind.

The PV module mechanical load tester therefore needs to provide controlled loading in the required directions according to the applicable test procedure.

6. Inspect the PV Module After Testing

After completing the specified mechanical load test, the PV module should be inspected for potential damage.

Typical inspection items include:

• Glass breakage
• Module deformation
• Frame damage
• Cell cracks
• Damage to soldered connections
• Delamination or other visible damage
• Changes in electrical performance

For more detailed inspection, mechanical load testing can also be combined with EL testing (Electroluminescence testing) to identify cell cracks and other defects that may not be visible during a normal visual inspection.

This combination can provide a more comprehensive evaluation of the mechanical reliability of photovoltaic modules.

Why Is Mechanical Load Testing Important for PV Modules?

Photovoltaic modules are generally designed for long-term outdoor operation. During their service life, they can experience repeated mechanical stresses caused by wind, snow, mounting structures, and other environmental conditions.

Insufficient mechanical strength may result in:

Mechanical load → Module deformation → Cell stress → Cell cracks or damage → Potential electrical performance degradation

In more serious cases, excessive mechanical stress may lead to glass breakage, frame deformation, or other structural failures.

For this reason, PV module mechanical load testing is an important part of photovoltaic module reliability evaluation and product qualification.

Applications of PV Module Mechanical Load Testers

A PV Module Mechanical Load Tester can be used by:

• PV module manufacturers
• Solar panel manufacturers
• PV research and development laboratories
• Third-party testing laboratories
• Certification laboratories
• Universities and research institutes
• PV quality control departments
• Solar panel reliability testing facilities

The equipment can be configured according to the required module dimensions, test loads, mounting methods, and applicable testing standards.

Conclusion

The basic procedure for a photovoltaic module mechanical load test can be summarized as:

Install the module → Set the test parameters → Apply the mechanical load → Hold the required load → Unload → Complete the required test procedure → Inspect the module

The main purpose of the test is to evaluate whether a photovoltaic module can maintain its structural integrity and reliability when subjected to specified mechanical loads.

For manufacturers and testing laboratories performing IEC 61215 mechanical load testing or MQT 16 testing, selecting an appropriate PV Module Mechanical Load Tester and correctly configuring the test load, mounting method, and test parameters are essential for reliable and repeatable test results.