The degree of EVA cross-linking that takes place during lamination can determine PV module lifetime. Fraunhofer CSE undertook a study of non-destructive measurement techniques for EVA cross-linking, ultimately producing and patenting a metrology method suitable for module manufacturing lines.
The CSE team demonstrated that a mechanical measurement of elasticity (indentation) is predictive of the level of cross-linking. This non-destructive technique is now available for in-line quality control in manufacturing. The method replaces a solvent technique, which is destructive and has low throughput.
Indentation testing is a reliable method to determine encapsulant cross-linking levels. Benefits include:
In 2011, Fraunhofer CSE licensed its method to LayTec AG, a manufacturer of in-situ metrology systems for thin-film processes. In May 2012, LayTec announced its X Link in-line metrology system, the first commercial application of Fraunhofer CSE intellectual property.
The X Link was exhibited at SNEC’s 6th International Photovoltaic Power Generation Conference Exhibition in Shanghai, China, and at Intersolar North America 2012.