Fraunhofer Institute for Solar Energy Systems ISE
Fraunhofer Institute for Solar Energy Systems ISE

Testing and Measurement Procedures

Tests for the Certification of PV Modules

In our TestLab PV Modules, we offer over 50 different test methods. These include all module tests from the IEC 61215 and IEC 61730 standards, as well as reliability tests that address specific aging mechanisms, such as the PID test (Potential Induced Degradation) or the LeTID test (Light and Elevated Temperature Induced Degradation). Below, we briefly present key tests and our laboratory equipment. If you do not see a specific test method listed, please feel free to inquire.

The tests required for the certification of PV modules can be categorized into tests for aging resistance, performance, and safety:

Aging Resistance Tests

  • Temperature cycling test, -40–85 °C, 200 cycles
  • Humidity-Freeze Test, -40°C to 85°C / 85% r.h., 10 cycles
  • Humidity-heat test, 85 °C / 85% relative humidity, 1,000 h
  • Cyclic mechanical load, 1,000 cycles, ±1,000 Pa
  • Static mechanical load, 3 cycles, e.g., ±5,400 Pa (depending on design)
  • Hail test, particle sizes 25 mm, 35 mm, 45 mm
  • Material creep test, 105°C, 200 h
  • UV test (dry), 60 kWh/m² at Tmod: 60 °C
  • Potential-Induced Degradation, 85 °C / 85% r.h.
  • Light and Elevated Temperature-Induced Degradation (Test Cycle)

Our Equipment

UV Irradiation

We have a total of 5 UV irradiation units for testing PV modules. The image shows an example of the configuration of a dual unit. Typical UV doses in stress tests are 15 or 60 kWh/m².

Features:

  • UV fluorescence technology (peak 340 nm)
  • UV-B content: approx. 4%
  • Optional option for significantly increased UV-B levels
  • Intensity: approx. 150 W/m²
  • Irradiated area: 280 x 170 cm²

Climate Chambers

We have 7 large climate chambers. For humidity-freeze tests, we exclusively use chambers with vertical airflow to ensure uniform temperature and humidity distribution.

Specifications:

  • Tmax: 180 °C
  • Tmin: -50 °C
  • r.h. max: 95%
  • Max. cooling rate: 5 K/min
  • Max. sample size: 280 x 170 x 120 cm³

Solar Climate Chambers

We have two solar climate chambers, which are used, among other things, for hot-spot testing.

Features:

  • Light quality (BBA and AAA)
  • Intensity up to 1250 W/m²
  • Max. module size: 220 x 130 cm²

© Fraunhofer ISE

Mechanical Loading (Basic)

Our pneumatically operated load test stand enables reproducible testing, for example, in accordance with IEC 61215 (MQT 16 and MQT 20) as well as according to customer-specific requirements. Our basic system is characterized by a large test area and high load variability.

Features:

  • Test area: 220 × 260 cm²
  • Maximum load (compression): 10,000 Pa
  • Maximum load (tension): 5,000 Pa
  • Maximum load cycling frequency: 0.1 Hz
  • Tests in accordance with IEC 61215 (MQT 16 and MQT 20) or according to customer-specific test programs

© Fraunhofer ISE

Mechanical Loading (Advanced)

We have specialized testing facilities for highly realistic simulations of load scenarios, such as inhomogeneous load distributions, as well as mechanical testing under freezing and other challenging conditions.

Specifications:

  • Test area: 150 × 280 cm² (non-uniform loads and rapid load cycling frequency up to 0.5 Hz) or 300 × 300 cm² (with temperature range from -40 to 80°C)
  • Maximum load (compression): 10,000 Pa
  • Maximum load (tensile): 5,000 Pa
  • Maximum load cycling frequency: 0.5 Hz
  • Number of load zones: 28 adjustable load cells with non-uniform load distribution
  • Temperature range: -40 to +80°C

© Fraunhofer ISE

Hail Test Rig

Hail impact loads are simulated using a pneumatically operated hail test stand. The weight and diameter are selectable. The velocity is precisely measured and can be adjusted to meet specifications.

Specifications:

  • Test area: 290 × 200 cm²
  • Hailstone diameter: 25, 35, and 45 mm
  • Continuously adjustable impact velocity and impact energies
  • Tests in accordance with IEC 61215 (MQT 17) or customer-specific test programs

Performance Measurement Tests

  • Power under standard test conditions (STC)
  • Bifaciality
  • Power output at nominal irradiance for bifacial modules
  • Low-light performance and irradiance dependence from 100 W/m² to 1200 W/m²
  • Temperature dependence from 15°C to 75°C
  • Spectral sensitivity
  • Power Rating Matrix according to IEC 61853-1
  • Angle dependence
  • Measurement of the nominal operating temperature (NMOT)

Our Equipment

© Fraunhofer ISE

Flasher

We have three flasher systems that are subject to quality control by the CalLab PV Modules.

Specifications:

  • Max. measurement area (STC): 300 x 300 cm²
  • Max. measurement area (TK, RAT): 270 x 160 cm²
  • Temperature range: 15°C – 75°C      
  • SR measurement (modules): 350 nm – 1100 nm
  • 29 bandpass filters

© Fraunhofer ISE

Solar Simulator

Novel PV technologies require spectral adaptability and continuous light for characterization. We were among the very first institutions to acquire a high-end LED-based solar simulator.

Specifications:

  • Measurement area: 2.30 m × 1.30 m (to be expanded to 2.50 m × 1.50 m)
  • Color channels: 29 LED channels in the 340 nm–1,600 nm range
  • Temperature range: 25–75°C

Angle Dependence

The dependence of module performance on the angle of incidence of light can be reproducibly determined using one of our flashers.

Characteristics:

  • Incident angle from 0 to 80°
  • Max. module size: 215 x 105 cm²

© Fraunhofer ISE

Preconditioning

To stabilize the samples prior to power measurement, we use, among other things, special constant-light simulators that allow us to maintain the module temperature within a specified range.

Specifications:

  • Total area: approx. 220 x 400 cm²
  • Irradiance: 1000 W/m²
  • IV monitoring and MPP tracking possible
  • Module temperature range: 50 ± 10 K

Nominal Module Operating Temperature

The nominal module operating temperature (NMOT) is measured on a special outdoor test stand. We also offer optional relative indoor comparisons (using solar climate chambers).

Features:

  • Number of test stations: 6 standard modules
  • Wind speed/direction
  • Irradiance
  • Tmod, Tamb

Safety Tests

  • Dry insulation test: 4 × Vsys + 2 kV
  • Leakage current test (insulation under moisture conditions) Vsys × 800
  • Surge voltage test up to 20 kV
  • Module breakage test
  • Hot-spot test
  • Grounding test
  • Vulnerability to cutting
  • Temperature test under irradiation (IEC 61730 MST 21)

Our Equipment

© Fraunhofer ISE

Insulation and Leakage Current Testing

To ensure electrical safety, the insulation resistance between the cells and the module surface is measured before and after each test. For the so-called wet leakage test (wet condition), the module is submerged in a water bath.

Specifications:

  • Max. test voltage up to 12 kV
  • Max. module sizes for WL: 300 x 150 cm²

Surge Voltage Test

To ensure electrical operational safety, a surge voltage test is also performed using a pulse generator. For this test, the module is fully or partially wrapped in a conductive film.

Specifications:

  • Max. voltage pulses: 20 kV

Module Breakage

The module breakage test ensures that no dangerous glass shards are produced in the event of glass breakage.

Specifications:

  • Drop weight: 45.4 kg
  • Drop height: 30 to 110 cm

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