Joint Research Activity 1 : Quicker lifetime prediction, through accelerated ageing tests and improved failure analysis

CdTe failure analysis using the VIM method
Electroluminescence test on CIGS module

The well-known IEC qualification test standards are considered as a good method for filtering out early failure issues and to guarantee a substantial part of useful life of PV modules in the field. In order to predict the lifetime of PV modules, accelerated ageing tests needs to be modified and extended much beyond the current qualification requirements. None of the available IEC standards provides help in differentiating module types with lesser or better endurance.

The development of accelerated test procedures has several objectives :
1. To make the innovation process easier and to shorten the design cycle: manufacturers will be more confident in applying and using new technologies if they can test the expected characteristics according to a quicker lifetime assessment procedure which has been developed and validated among the main European research laboratories.
2. To help in providing the end-user with more detailed information on the PV module, whatever the climatic and installation conditions. A greater accuracy on the lifetime prediction ends up with a better estimation of the cost of ownership of PV systems.
3. To develop a rating system and gradually improve the IEC standards to take into account all types of PV technologies.

In relation with the service activities provided by the research infrastructures, this activity will result in :
• Improved and harmonised procedures for accelerated ageing tests, if possible related to lifetime prediction of PV modules
• Recommendations for new testing equipment to perform these accelerated aging tests
New methods for failure analysis, in order to more precise with recommendations on the module design

This work will address most of the PV technologies available on the market :
- glass/glass, glass/tedlar, and flexible metallic or polymer substrates
- crystalline silicon, thin-films, organic PV, etc.
- ground mounted or building-added (which were the conventional ways of installations), or building-integrated which gives new constraints (higher temperatures for instance)

Three substasks are planned :

JRA 1.1:  Test facility and failure analysis inventory
This work is required to create a portfolio of testing infrastructures. This ensures optimal use of the testing facilities available within the consortium. Matching of demand and availability will be required.

JRA 1.2: Accelerated ageing tests
This work will be strongly depending on indoor testing. It will include the following actions :

  • Performing round-robin intercomparison degradation tests (UV, moisture ingress, hi-potential testing, mechanical loading, etc.)
  • Developing accelerated ageing procedures to be able to predict the long-term degradation process in a few months. New test methodologies need to be defined and validated in an extended and coordinated way with field testing in extreme outdoor conditions. A concerted international work programme is crucial to handle the associated workload.
  • Validating ageing models by comparison with outdoor exposed modules.

JRA 1.3: Improved failure analysis methodologies
New characterisation methods, destructive or non-destructive, will be developed of improved to support the understanding of PV module degradation processes.

 

The next event related to this topic is the <media 193>Workshop on PV Module Reliability </media>in Lugano, Switzerland, on May 3rd & 4th 2012.