Strategies for minimizing induced thermomechanical stress in glass–glass PV modules with half cells identified using finite element modelling

The thermomechanical stress developed through interconnection, lamination and initial thermal cycling of multi-busbar (MBB) interconnected glass-glass solar modules was investigated using finite element modelling. The simulated results showed that highly localized stress was induced in the silicon (Si) cells after interconnection. Due to the compressive effect from the glass, maximum tensile stress in Si decreased after lamination, whilst maximum von Mises stress in Cu ribbons increased. Both stresses in Si and Cu further increased during thermal cycling. Copper ribbons with a lower aspect ratio and smaller cross-sectional area induced lower stress in Si. While higher stress was developed in thinner Si cells, increases in cell length resulted in a higher stress in the Cu ribbons. By aligning the front and rear contact pads on the cells, the Si tensile stress can be effectively reduced throughout the thermal processes.