Finite-element structural modelling of laser welds. Application to aluminium connections in Li-ion prismatic batteries

This paper investigates the influence of process parameters on the mechanical properties of laser-welded aluminium joints through experimental and numerical studies. The experimental analysis included hardness measurements, microstructural imaging, and cross-weld tensile tests at temperatures up to 200 °C. Results indicated that size variations in the heat-affected zone (HAZ) significantly influenced mechanical properties, with increased HAZ extension leading to lower ultimate tensile strength (UTS) and higher engineering strain to failure. Thermal sensitivity was consistent across base material and welds. A suitable cohesive zone model (CZM) was proposed to represent the mechanical behaviour of the connections in large-scale finite element models. Furthermore, the performance of the CZM and of a shell element approach (SEA) were validated against the experiments and compared in a numerical study. The simulations showed that the CZM has the potential to replace the SEA in simple load cases while still providing reasonable results for complex scenarios. • Investigated mechanical effects of HAZ size in laser-welded aluminium joints. • Conducted tensile tests up to 200 °C and microstructural/hardness analyses. • Developed a cohesive zone model (CZM) capturing plasticity and fracture. • Validated CZM against experiments and compared with shell element approach (SEA). • CZM offers comparable accuracy to SEA in simple load cases with significantly reduced computational cost.