ECN publication
Ultrasonic welding; a connection technology for flexible thin film modules
Published by: Publication date:
ECN Solar Energy 1-6-2004
ECN report number: Document type:
ECN-RX--04-058 Conference Paper
Number of pages: Full text:
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Presented at: 19th European Photovoltaic Solar Energy Conference and Exhibition, Paris, France, 7-11 juni 2004.


Commercial ultrasonic welding equipment has been modified in such a way that it is applicable to flexible foils. Individual welding parameters, such as force, time and amplitude are optimised for the electrical connection of CISCuT (CuInS2 on Cu-Tapes) solar cells. By fine-tuning the ultrasonic welding force, we succeeded in making stable and reproducible connection between aluminium tape and the front contact respectively the copper back contact. As busbar material aluminium and copper metals have been tested. Outside the welding area no material changes were observed. Ultrasonic welding and encapsulation of the foils have not influenced the solar cell performance. The measured contact resistance is very low (<4 m. on 1.5 mm2 contact area). It is possible to weld several tapes on short distances. Thermal cycling between -40°C and 80°C or 85%/85°C damp/heat exposure do not influence the electrical contact at the weld.

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