Mechanische Eigenschaften und Ermüdungsverhalten von Solarzellenverbindern

Flat, solder coated copper wire is used for the electrical cell interconnection in crystalline photovoltaic modules. The mechanical properties, especially the yield strength and resistance against low cycle fatigue, are important product properties for the photovoltaic industry. Suitable mechanical properties are required for the processing of the fragile photovoltaic cells. On the other hand, copper interconnect ribbon is subject to cyclic bending in the module. This cyclic deformation can lead to fatigue breakage of the interconnect ribbon. Possible results of such failures are electrical losses and even safety risks. The aim of the diploma thesis was to evaluate the range of mechanical properties which can be achieved with the chosen manufacturing process. Furthermore, the purpose of this study was to investigate how the achieved mechanical properties influence the low cycle fatigue properties of the ribbon. Differently heat treated flat wires were investigated in terms of microstructure, mechanical properties and low cycle fatigue performance. A test device and procedure for cyclic bending tests was developed.