A Study on Mechanical/Metallurgical Characteristic of Welded Joints According to Heat Input and Gap in Al/Cu Laser Welding

Abstract

The electrical connectivity and tensile strength between battery components are crucial factors for enhancing battery performance in electric vehicles. In this study, the welding characteristics of aluminum-copper welded joints manufactured using the multi-core laser welding process were studied according to the output power of core/ring laser. Moreover, the tensile strength change behavior according to various welding processes, such as single/two-line welding, and welding gap distance were measured. The results revealed that increasing the output power of the ring beam led to an increase in the tensile strength. However, excessive laser power would increase convection between aluminum and copper during welding and cause defects owing to the difference in the solidification temperature between the two materials. In addition, the mechanical properties were improved by increasing the distance between the two lines of straight laser welding. As the spacing increased, the fraction of the equiaxed microstructure increased, and grain growth was suppressed to improve mechanical properties.