Reliable and Automatable Solution for Shingle Bussing |
Daniel von Kutzleben, Najwa Abdel Latif, Julian Weber, Torsten Rößler, Achim Kraft, Holger Neuhaus Fraunhofer Institute for Solar Energy Systems, Freiburg, --, Germany |
Shingle matrix technology is a way for creating efficient and visually appealing photovoltaic (PV) modules resistant to partial shading. The specific technical challenge ad-dressed in this work is connecting metal bus connectors to shingle strings and shingle matrices, given the unequal coefficients of thermal expansion (CTE) between copper and silicon. To counter this, the proposed solution introduces the use of an electrically conductive tape (ECT). Applied post-cell interconnection, the ECT minimizes thermo-mechanical stress due to the absence of a curing step. Adhering the ECT to a large area of the rear sides of cell rows ensures low ohmic contacts. Experimental results evaluated various ECT products and widths after accelerated temperature cycling (aTC). Notably, there is a correlation be-tween ECT width and degradation post aTC, emphasizing the need to optimize this parameter. The derived module design, enabling an automated bussing, minimizes thermo-mechanical stress during production. Reliability testing of full-format matrix modules demonstrates durability according to industry standard IEC61215, although challenges emerged in the connection between ECT and cross connectors. |