The photovoltaic (PV) industry relies on international standards to ensure the safety, quality, and quality of solar modules. One of the critical certifications that play a pivotal role in this process is the IEC 61215. This certification was developed by the International Electrotechnical Commission (IEC). The IEC is a leading global organization which develops consensus-based international standards for different electric technologies. These standards are developed based on reviewing the literature on the known failure modes and degradation rates in the last 5 years and are updated every five years.
The IEC61215 standard outlines many required standards that comply with the actual requirements of the PV industry. It aligns the requirements for different crystalline Si technologies for manufacturers and provides a clear structure of general requirements and the test methods and techniques. Moreover, minimum design requirements and qualification conditions –like clearance and creepage distances– are required to guarantee safe operation at high voltages (manufacturer can choose 1000, 1500v applications). Module manufacturers and the test bodies conducting the certification scheme couple the two norms to save costs and for efficiency reasons.
This article explains the IEC 61215, its importance in the PV industry, and the certification process, limitations & challenges.
Critical Note
The IEC61215 is primarily used to indicate that the module will not suffer infancy failure issues in the first 5 – 10 years of its lifetime in temperate/continental climate conditions. It is not an indicator of reliability and/or durability. Due to its five-year update cycles and given the quick uptake of new technologies (cell types, sizes, applications), some failure modes/degradation rates may not be reflected till the new update of the certification scheme. See our blog on IEC62309 for more insights.
Figure 1. Fraunhofer USA IEC61215 to tackle Infant Mortality Coverage
Additionally, parties like RETC see that there is a high frequency of production modules that fail IEC61215 tests when randomly selected from the manufacturing hall and tested. Typical tests that they struggle with are Thermal Cycling, Damp Heat, wet leakage, and variations in the STC measurement.
IEC61215 Certification Scheme
The IEC 61215 standard focuses on the performance of crystalline silicon and thin-film PV modules. Its primary objective is to ensure that modules can withstand prolonged exposure to environmental stress without losing more than 5% degradation in performance. This IEC test has to replicate the first 5 – 10 years of its lifetime to indicate that the module will not suffer a higher failure rate in the first years, typically known as infancy failure events.
The IEC61215 test scheme for testing solar panels indicates the minimum design requirements that assure the safety of the product during normal operation.
Figure 2. IEC61215 Test Diagram
The PV test standard focuses on identifying potential failure mechanisms in PV modules and determining their ability to endure various environmental stresses, such as:
- Temperature variations
- Humidity
- UV exposure
- Mechanical stress (wind, snow loads, and hail impact)
- Thermal cycling
As to replicate conditions in which the commonly known failure modes and degradation rates may occur so as to give assurance that these modules tested & certified do not suffer these infancy mortality issues. As researched by the IEA PVPS team in figure 3, the main challenges in the first 5 years are:
- Delamination
- LID
- LETID
- Glass Breakage
- Interconnect failures
- Junction Box failure (diode failure, overheating, detached)
- Microcracks
- Shunts/Arcing
- PID (note this also has a separate IEC62804 certificate)
- AR coating loss
- Isolation Failures
Figure 3 & 4. IEA PVPS Assessment of PV Modules Failures, 2017
Key PV Tests Under IEC 61215
Each IEC test is designed to simulate real-world conditions and prevent early failure of PV modules:
Thermal Cycling Test (TC): Evaluates the module's resilience to temperature fluctuations between -40°C and +85°C.
Damp Heat Test (DH): Assesses the module’s ability to withstand high humidity and temperatures (85°C and 85% humidity) over an extended period.
UV Preconditioning Test (UV): Simulates long-term exposure to ultraviolet radiation to evaluate material degradation.
Mechanical Load Test (ML): Simulates external mechanical forces such as wind, snow, and handling to ensure structural integrity.
Hail Impact Test: Verifies the module's ability to withstand hailstones of specified sizes at a given speed.
Outdoor Exposure Test: Exposes the module to natural outdoor conditions for a specific period to validate its performance to attain performance at
Performance testing: Measures the power of the module and the effect of temperature thereof in different conditions, this 'solar panel flash test' includes IV curve analysis to ensure optimal efficiency.
These tests are designed to simulate the initial 5 – 10 year lifespan of a module, providing manufacturers, investors, and installers confidence that the module will meet performance expectations and not have major infancy failure issues.
IEC61215 Testing Sequences
These tests are done in different sequences outlined in the standard. After the initial tests performance & safety tests, the modules are separated and subjected to one of the different sequence tests. The sequences are called A, B, C, D, or E, and after that tested again for efficiency and safety. Each single sequence contains stress tests that specifically aim at clarifying one of the identified main degradation causes that are commonly faced in the field.
Sequence A is the control sequence which contains mild conditions that provide basic characterization for the modules under STC (Standard Test Conditions). It also includes performance at low irradiance. Note for .PAN file generation (digital datasheet), the IEC61853 is used which provides a matrix for insight on performance at different irradiances and temperatures.
Sequence B tests the hot spots and outdoor behavior. Hot spots, which can cause accelerated degradation of modules and are caused by near, core, or far shading a both an important safety and performance consideration. Given diodes take up the slack for shading these are thoroughly tested, particularly as solar panel diode failure is a common failure in the first 5 years.
Sequence C combines various stress tests in which the modules are initially preconditioned with UV light and after subjected to 50 thermal cycles and 10 humidity freeze cycles. These conditions are done to replicate UVID issues, delamination, corrosion of interconnects, microcracks, and weathering impacts (dynamic wind loads). Thermomechanical issues are arising due to the large area that solar panels are now taking up.
Sequence D contains the thermal cycling test in which the module is subjected to 200 thermal cycles. These thermal cycles can replicate night to day shifts in temperate climates and see if there are issues with interconnect failures or microcracks.
Sequence E combines the damp-heat test together with the mechanical stability tests. These tests are to replicate hot & humid locations within the temperate/continental climate where modules more frequently have a higher degradation & failure rate. The static mechanical tests snow loads on modules and are static as compared to Sequence C dynamic mechanical testing.
The above sequences ensure the PV modules are tested for all the important parameters which include basic Diagnostic tests, Electrical parameters, Performance Parameters, Thermal, irradiance, Environmental and mechanical parameters.
Pass/Fail Criteria
PV modules may not exceed more than 5% of their initial performance or the test is failed. Re-tests can occur typically twice, which require a root cause analysis by the module manufacturer and re-doing the failed test. Two modules must then under. Another general passing criteria is that after each IEC test the wet leakage current test should be repeated, and no evidence of any visual defect should be seen. A module manufacturer may only fail the IEC61215 test twice. The third time a whole re-test is required from the top of the scheme.
Production Site Audits
Solar module manufacturers that have their solar modules IEC61215 certified must have their sites audited; notably, only that line is then certified to produce those certified solar panels (unless there are clear license agreements and quality control for OEM locations). The audit is conducted according to the CIG023 inspection format under strict quality control standards, which an inspector will follow. Any minor deviations based on the earlier documentation must be addressed within a given time or by the next yearly inspection. Major deviations can cause the certification to be revoked or suspended till they have been addressed. However, due to the large number of different sites and few inspectors, some audits may be delayed or not executed.
IEC62915 Re-test Baseline
Typically, module manufacturers will have a module tested with one specific BOM. However, in the case that the module manufacturer wants to vary between BOM/CDF the certification body will look at the IEC62915. The same body will also do so when notified if the module has had its BOM changed to know which re-tests to execute. All in all, it provides test sequences if encapsulants, solar cells, glass, or back sheets have been changed and when it is or isn't required. It is not uncommon that produced modules may deviate from the certified BOM due to supplier variations and the manufacturing not informing the test body of the change.
Competent Body Test Laboratories (CBTL) & UL61215 & 61730, Metro or JET
Only Competent Body Test Laboratories (CBTL) which are also ISO1725 certified, which are audited and certified to execute solar PV certification and testing can provide IEC61215 certification. They follow the Certified Body (CB) Scheme, which is a more global approach to proving compliance for Product Safety. Instead of an “NRTL” for the United States, an approving laboratory is called a CBTL. These are companies like TUV Rheinland, TUV Nord, TUV Sud, Kiwa, VDE and others. These same test & certification bodies may provide CBTL reports to help when entering different markets that require further testing. Examples here are the United States (UL), Japan (JET), and Brazil (Metro).
The CBTL reports indicate which tests have been done, allowing the local certification body (JET, UL, or METRO) to execute the tests that are different and not do the whole certification scheme again. These bodies also must adhere strictly to the IEC62915 norm and are audited for the reasoning hereof when testing modules with one or various BOMs and which tests must be done.
What are common problems detected during IEC 61215 certification testing?
70% of “standard” modules that undergo certification pass, often failing thermal cycling, UV, dynamic mechanical load, and damp heat testing (thus exceeding the 5% degradation limit). 40 – 60% of innovative technologies fail the certification scheme. Thus, the reason why many parties have in-house labs that include these test setups is to ensure their modules pass, but also the investment into certification is worth its while. The main causes of failure are often:
- Failure of components and connections, like busbar failure or contact defects
- Failure of components in extreme outdoor conditions
- Detection of leakage and moisture effects on the PV modules and their performance
- Short circuit in solar cells
- Cracks in PV modules that cause performance loss
- Delamination
Moreover, randomly selected production modules often fail thermal cycling and damp heat testing when re-tested as according to IEC61215 testing.
Importance of IEC61215
This certification is essential for the global PV industry. They ensure that solar modules not only perform well in the first years but also operate safely under the expected environmental and operational stresses.
- Manufacturers who obtain IEC 61215 can provide evidence that their PV modules will perform well in the first 5 – 10 years.
- Many countries and regions require PV modules to be IEC-certified to ensure they meet local regulatory requirements. This enables manufacturers to sell their products in international markets.
- PV modules that pass IEC certification are more attractive to investors, project developers, and customers, as they provide assurance of safety and performance.
- IEC certification reduces the risk of failure, underperformance, or safety hazards in the field, helping to protect financial investments in solar energy projects.
- Certified PV modules offer end-users confidence that the products they are installing will perform as expected and meet international safety standards.
- Note that the certificate is only valid for the module that is produced with the same Bill of Materials/Construction Design Form as that what was certified. Due to supplier variations, the produced module could be non-compliant. Moreover, note that the validity of this certificate is 5 years on the basis that internal and external audits are conducted.
Conclusion
The IEC 61215 acertification is critical to ensuring the initial performance and safety of PV modules in the solar energy industry. IEC 61215 focuses on performance, ensuring that modules perform well initially in harsh environmental conditions. However, it is important that close attention is paid to the compliance of the production module with the certified module with regards to its BOM, but also that audits have been taking place to ensure quality.
Sinovoltaics provides both factory audits and production monitoring in which, amongst others, the state of the certification, its audits and the BOM of the module are verified to provide zero risk projects.
Recommended Sinovoltaic Services
Factory Audit – to determine that the site is at minimal meeting the IEC61215 requirements and documentation, moreover that they align with the product produced.
Production Monitoring – to ensure that the modules are made to the best practices and there are now batch variations that can cause deviations in degradation rates & failure modes.
Sinovoltaics Lab Service
- Basic:
IV Testing: to verify the STC power range
Wet Leakage Tests: to verify the safety of the module due to production & material variations
EL Testing: Microcracks that result from production variations and poor handling
Gel Content and/or Peel Tests: Verification that the module has been properly laminated and will not delaminate in the first 5 years in the field
- Advanced
Thermal Cycling: To test for interconnection failures and delamination
Damp Heat: To test for degradation in the most strenuous climate where modules often fail.
Contact Sinovoltaics today for optimizing your Quality Assurance to ensure your PV modules meet the IEC 61215 certification standards and guarantee optimal performance and safety for your solar projects!
