LayTec has introduced a new in-line metrology system X Link that is designed to provide fast and accurate evaluation of the level of ethylene vinyl acetate (EVA) cross-linking directly after the module lamination process. It can be integrated in any c-Si or thin-film based solar module production line and is claimed to offer 100% coverage for process and quality control.
The lamination process is critical to the long-term reliability of a module, which requires reproducible processes. Therefore high temperature uniformity with +/- 1 degree Fahrenheit coupled to high heating rates being required. In high-volume applications gaining accurate insight into heating zone and exposure time of the laminated EVA back sheet could further improve module reliability, quality control and process optimization. Gel fraction and creep test are the two main methods used for the detection of the correct cross-linking EVA. However, both are time consuming and destructive, preventing the use in high volume production.
LayTec has developed an in-line device for monitoring the degree of cross-linking in EVA laminates in close cooperation with Fraunhofer USA. This method utilizes a rheological approach. It analyses the response of the laminated EVA back sheet combination. The measured stiffness is directly correlated with the level of cross-linking. The data can also be given as ‘percentage gel content’ equivalent. Placed directly after the laminator, the tool gives direct feedback to the lamination process for the adjustment of heating zones and exposure times. LayTec X Link is said to improve lamination yield by real-time control and provide a detailed proof of the long-term stability of PV modules thereby increasing bankability. This system replaces the common and coarse gel content test.
EVA back sheet lamination post inspection and can be integrated in any c-Si or thin-film based solar module production line.
The in-line version is based on highly robust industrial grade embedded system protocols and can be directly connected to production systems and SPC databases by a large variety of protocols along with clear user visualization for quick on-line inspection.
May 2012 onwards.