Comparison of QCW pulsed laser and single-mode CW laser on the welding of power cell lugs

Aluminum alloy is the main material of pole ear plate and bus bar of power cells for new energy electric vehicles. In this paper, quasi-continuous wave (QCW) pulsed laser and single-mode continuous wave (CW) laser were used to conduct laser lap welding experiments on a 0.5 mm thick 1060 aluminum alloy and 2 mm thick 6061 aluminum alloy. The effects of these two laser sources on weld zone morphology and tensile force were compared. The experimental results show that the QCW pulsed laser welding is more likely to have porosity cracks and other defects, while the overall weld performance of the single-mode CW laser welding is obviously better than the former. In addition, the maximum tensile strength of the weld joint in QCW welding is about 861.02 N, while it can reach 1521.36 N in CW welding. The tensile force with CW laser welding is much higher than that required by the power battery industry standard, i.e., the tensile force of 800 N.