19 IEC 61215 Tests to Identify Quality Solar Modules

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If you plan to install solar panels on your roof and enjoy the abundant energy generated from the sun, you need to be aware of the quality standards that ensure the solar modules can operate consistently and reliably for 25 years.

While consumer electronics are only expected to last for 2-5 years, the 25-year expectancy of solar panels cannot be achieved without a set of stringent quality and performance tests.

The most popular standard for the solar market is IEC 61215, and it is the compulsory qualification to pass to participate in key solar markets such as Europe and Australia.

It covers all the bases in making sure solar modules can function for 25 years on your roof.

IEC 61215 is the industry standard that defines the design and qualification of silicon PV modules for long-term operation in open air, terrestrial applications.

With a long history dating back to 1993, the IEC 61215 standard has undergone multiple iterations, with the latest 2016 edition containing 19 tests designed to confirm the engineering quality of the solar modules.

1. Visual Inspection to Screen Out Cosmetic Failures

Before getting to the fancy equipment and testing procedures, the first step of the IEC 61215 standard is to look for cosmetic oddities that indicate greater performance and reliability problems.

Visual failures may include:

  • Broken or bent materials, glass, frame, junction box that can impact function.
  • Bubbles or delamination in the modules may lead to a short circuit.
  • Burnt marks on components may cause failures.
  • Solar cell cracks and corrosion can reduce energy production.
  • Poorly soldered joints can lead to open circuits.
  • Any exposed conductors can lead to leakage currents.
solar mdoule visual inspection
Visual inspection of solar panels in the production line.

Visual inspection is a major part of WINAICO’s quality control, where every panel has to pass our visual quality inspection to meet our production standards.

2. Performance Measurements at STC to Define the Module Specifications

Power output and module efficiency are probably the two most discussed specifications when choosing solar modules.

Solar modules are measured at STC, Standard Test Conditions, to benchmark the standard performance specifications:

  • Light irradiance of 1,000 W/m2.
  • Solar cell temperature of 25°C.

Maximum power measurement at STC divided by the surface area of the module tells us the module efficiency.

The higher the module efficiency means you can pack more energy production on your roof.

The STC maximum power output is measured before and after each sequential test, where a power degradation <5% qualifies as a sound solar module.

3. Insulation Test Confirms the Solar Module Is Safe to Operate at System Voltage

A solar installation can have system voltage as high as 1500 V flowing in the solar module conductors such as cables, solar cells, and busbars.

The insulation test can confirm the dielectric strength of glass, EVA, and backsheet under the influence of high voltage.

The insulation test feeds 1000 V plus 2 times the highest system voltage to the junction box output and the frame (after grinding off the surface insulation first), to test for the presence of a dielectric breakdown.

solar module insulation test
Use high voltage across the bare frame and junction box output to test for insulation.

Good insulation on a full-size module is greater than 40 MΩ/m2 in insulation resistance.

This way, the module frame would be safe to touch in a live PV system.

4. Measure Temperature Coefficients to Understand Module Performance in Different Weather

WST-410MGX IV at different temperatures
Solar module IV curves at different temperatures.

Solar modules’ electrical properties change at different temperatures, so it’s important to understand how temperature changes affect energy production.

The test lab would measure the IV curves of the solar module at different temperatures to provide us with the impact of temperature on the power output.

The resulting temperature coefficients are outlined in the datasheet and used to simulate a PV system performance.

5 and 6. Determine NMOT and Maximum Performance at NMOT to Simulate Real-World Operating Conditions

The sun causes solar modules to heat up, leading to small changes in module efficiency.

NMOT, or Nominal Module Operating Temperature, test takes into account the temperature rise to simulate the solar module performance in a real-world operating environment:

  • Light irradiance of 800 W/m2.
  • Ambient temperature of 20°C.
  • Wind speed of 1 m/s.

The power, current and voltage measurements found by NMOT with elevated cell temperature provide a better indication of how the modules can perform in a PV system.

7. Performance at Low Irradiance Determines a Module’s Energy Output in Low Light and Poor Weather

solar cell low light performance
WINAICO’s panels have better performance even at low irradiance.

Solar modules’ electrical properties change at different temperatures, so it’s important to understand how temperature changes affect energy production.

The test lab would measure the IV curves of the solar module at different temperatures to provide us with the impact of temperature on the power output.

The resulting temperature coefficients are outlined in the datasheet and used to simulate a PV system performance.

WINAICO panels’ better low-light response means the panels can begin producing energy earlier in the morning, and turn off later at dawn, to give you the most energy production on the roof every day.

8. Outdoor Exposure Tests Can Detect Early Defects

Sunlight is a trigger of early degradation in solar modules due to Light Induced Degradation (LID) and heating.

The outdoor exposure test leaves a module in the sun until it accumulates 60 kWh/m2 of energy, equivalent to 20 days in Europe (or 2 weeks in Australia) to look for early signs of power degradation due to LID and other component failures.

9. Hot Spot Endurance Test Outlines the Temperature Increase When Individual Cells Are Shaded

Solar modules can be partially shaded during operation from fallen leaves, soiling and shadows of nearby trees and street lamps.

The partially shaded solar cells become reverse-biased to create hot spots on the panel.

The hot spot test can show the impact of temperature increase on individual cells during operation.

10. UV Preconditioning to Breakdown Poor Quality Lamination Materials

UV light can weaken the structure of lamination materials such as EVA and backsheet, and the waterproofing of the junction box.

The UV preconditioning test is performed before Thermal Cycling (TC) and Humidity Freeze (HF) tests to simulate how sunlight can speed up the panel degradation in changing weather conditions.

The UV preconditioning test parameters are:

  • Accumulative UV irradiation (280 nm – 400 nm wavelength) of 15 kWh/m2.
  • Module temperature at 60°C.

11. Thermal Cycling Simulates the Outdoor Temperature Changes

temperature cycling
Temperature changes designed to simulate the cycling of day and night.

A typical PV system experiences dramatic temperature changes day and night outdoors.

The Thermal Cycling (TC) test uses 200 cycles of extreme temperatures (-40°C and 85°C) to speed up the deterioration caused by temperature changes.

The material expansion and contraction from temperature changes can cause lesser quality modules to weaken and lead to loss of power.

12. Humidity Freeze Simulates the Impact of Frost

humidity freeze
Combine temperature changes with humidity to simulate the impact of frost.

We all know that water expands in volume when frozen into ice.

If water seeps into the module on wet days and freezes into ice during cold days, the ice can weaken the lamination and mechanical strength of the solar panels.

The Humidity Freeze (HF) test combines humidity and heat with freezing cold (85°C at 85% relative humidity and -40°C) for 10 cycles to look for leaky materials that can be damaged by frost.

13. Damp Heat Test Can Detect Leaky Lamination

The HF test only has short periods (around 20 hours per cycle) of high temperature and high humidity to create water vapour, while the Damp Heat (DH) test exposes a module to 1000 hours of continuous high temperature and humidity.

The constant +85°C and 85% relative humidity can simulate the effects of heat and condensation on a solar panel in a tropical climate.

The strength of lamination and insulation are severely tested to make sure droplets do not form near the solar cells to cause power degradation.

14. Robustness of Terminations Test Evaluates the Integrity of Cables

Solar cables need to last more than 25 years like the panel itself.

Pulling forces of 40 N are applied to the junction box cables both horizontally and perpendicularly for 10 seconds to ensure the cables are secure and safe for long term use.

15. Wet Leakage Current Test Confirms the Safety of the Module in Wet Conditions

Solar modules need to operate reliably and safely when soaked in water.

Whether it’s in the rain, fog, dew or melted snow, the solar module should provide good insulation to make sure the system operators are safe around the PV system.

The wet leakage current test submerges the module in a water tank, and measures the insulation resistance under maximum system voltage for 2 minutes.

A full-size module should have greater than 40 MΩ/m2 in insulation resistance to pass this test.

16. Static Mechanical Load Tests the Structural Strength of the Module

Wind, snow or even a person are some of the most common mechanical stresses that a solar module can face.

The standard Mechanical Load (ML) test applies 2,400 Pa for an hour to the front and back sides of the solar module in an alternate fashion.

WINAICO’s modules are designed to endure a 5,400 Pa test load on the front side to make sure they can survive the toughest installation environment.

17. Hail Impact Test Strikes the Module Glass With High-Speed Ice Balls

Hailstones can cause profound damage to properties on rare occasions they happen.

Since solar panels need to survive for more than 25 winters on your roof, the hail impact test becomes quite necessary, especially for colder regions.

The standard IEC tests strike modules, at 11 locations, with 25 mm diameter ice balls travelling at 23 m/s, while WINAICO asks for the advanced test of 35 mm diameter at 27.2 m/s (4 times the impact energy of the standard test).

hailstone impact test
35 mm diameter ice balls are propelled towards the modules at 27.2 m/s.

18. Bypass Diodes Are Tested Beyond the Maximum Short Circuit Current for Safety

Bypass diodes inside the junction box are the key safety component to protect defective solar cells from overheating.

When a solar cell is not working, either due to defects or shading, the bypass diodes would bypass the cell string to prevent further cell heating.

The bypass diode test simulates hot and high current situations:

  • Module temperature at 75°C.
  • Conduct 1.25 times short circuit (ISC) through the diodes for 1 hour.

A good quality bypass diode should work normally under such test conditions.

19. Stabilization Test Exposes Module to Light Until Output Power Is Consistent

Use light exposure to stabilize the solar module power.

The output of solar cells can fluctuate when exposed to light, so a stabilization test can help us precondition the solar module until we get a stable output ready for tests.

The test sample is subjected to 2 iterations of 10 kWh/m2 light exposure, where the difference between the maximum and minimum Pmax should be less than 1% of the average Pmax.

Once a WINAICO solar module passes a combination of the 19 tests outlined in IEC 61215, you can be sure that a WINAICO module can produce top performance reliably on your rooftop for a long time.

To learn more about how WINAICO solar technologies can help with your rooftop energy production, please get in touch with us.

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