Reliability of Aluminum-Copper Contact in PV Modules

For the cross connectors of photovoltaic cells interconnected with an aluminium foil, contacts of aluminium and copper are required to contact the copper-based junction boxes in the module. In this study, three concepts for the realization of such a module are presented and mini modules are assembled in which the relevant contacts are investigated with different joining techniques and materials. The mini modules are evaluated regarding their reliability after ageing with damp heat and thermal cycling tests in the climate chamber. Both the contact between aluminium foil and aluminium bussing as well as the contact between aluminium foil and copper bussing can be realized without significant power loss due to the contact. Furthermore, no significant degradation can be observed after the reliability testing of 3000 hours in damp heat test condition and 600 cycles of thermal cycling test condition.