Use finite element modelling to characterise the stress evolution in Multi Busbar interconnected half-cell tiled modules after soldering and lamination

In this work, finite element modelling was used to investigate the stress evolution in solar photovoltaic modules after soldering and lamination. The impact of cell overlapping in modules and the selection of solders on maximum stress and stress distribution of Multi Busbar modules was investigated. Simulation results predict that the maximum 1st principal stress of up to ∼230 MPa in Si cells occurred at the edge of outer Ag pads. In addition, highly localised stress area occurred at the overlapped area when tiled which was verified by Raman spectroscopy. The application of SnBi solder can effectively reduce the maximum 1st principal stress in the tiled module from more than 220 MPa to ∼160 MPa, though its material properties tend to result in higher stress in the interconnection with a cell gap than SnPb solder.