Stress evolution and degradation in zero-busbar silicon photovoltaic modules under thermal cycling: A finite element study

Zero-busbar silicon-based photovoltaic modules are emerging as innovative designs in renewable energy systems, yet their thermo-mechanical reliability under operational stresses remains a critical concern. This study employs transient-state finite element analysis (FEA) to investigate stress evolution in silicon cells, solder joints, and glue joints during thermal cycling. Numerical simulations reveal that structural symmetry significantly influences stress concentrations, particularly at cell-to-cell interconnections. The analysis further demonstrates that glue pad properties exhibit minimal impact on overall stress distribution, while multi-cycle thermal loading highlights progressive hysteresis behaviour in solder joints, driven by accumulated plastic deformation. These findings highlight the importance of geometric optimisation and solder joint durability in enhancing the long-term reliability of zero-busbar photovoltaic modules. This work provides actionable insights for designing robust, high-efficiency systems capable of withstanding real-world thermal stresses. • Transient FEA reveals stress evolution in 0BB PV modules under thermal cycling. • Cyclic hardening and hysteresis stabilisation observed in solder joints after initial thermal cycles. • Enlarged outermost solder pads mitigate peak stress concentrations at critical locations. • Glue pad effects on solder joint stress are minimal due to low stiffness and slow relaxation. • Solder degradation correlates logarithmically with PV power loss over time.