Laser wobble welding of steel to Aluminium busbar joints for Li-ion battery packs
M. Chelladurai Asirvatham, Sam G. Collins, Iain Masters
Abstract
In this work, Laser wobble welding of Steel to Aluminium busbar joints was investigated for Li-ion battery pack applications. The effect of wobble amplitude on the properties of the weld was studied. It is observed that wobble amplitude significantly influenced the weld geometry, microstructure, mechanical strength, and electrical resistance. As wobble amplitude increases the weld depth reduces linearly and the severity of weld cracking was significantly reduced. Welds with an aspect ratio below 1, produce almost a crack-free microstructure. The optimum wobble amplitude was found to be 0.8–1 mm for the selected laser power density. Under optimum parametric conditions, the weld strength reaches 1 KN, equalling that of the thin steel sheet. In addition, the optimum welds showed a low volume of intermetallic phase formation which improved both electrical conductivity and tensile strength. The results of this study facilitate an effective joining solution for a cost-effective aluminium busbar material to steel-cased cylindrical cells.