4. 1 PV Module Design, Manufacture, Performance and Reliability
Back Contact, Module Manufacturing, Qualification and Testing, Ribbons
Summary / Abstract:
Thermomechanical stress induced by interconnection process, which can cause cell bowing, is enhanced for interdigitated back contact ( IBC) solar cells. Efforts are made therefore at laboratory and industrial level to lower cell bowing in cell string, while targeting a reliable interconnection at fast, competitive production flow rates. Two widely available possibilities for interconnection of solar cells are considered in this research work: soldering versus gluing with electrically conductive adhesive (ECA). While soldering with widely used soldering alloys, like Sn60Pb40, is considered as a straight forward, well characterized and understood technique , utilization of conductive glues requires a far more specific and intensive analysis. Results from test setups and sample designs will be used in a detailed simulation tool (FEM) environment to obtain predictions for thermomechanical stress initially at cell string level; this will facilitate the qualification process, through a correlation between thermomechanical stress and cell bowing via simulation. Overall this study aims for defined feasible processes for soldering, respectively for gluing of cells, with focus on full cell format, which will ease the implementation of IBC ZEBRA cell in mass production at present competitive throughput level.