Characterization of dissimilar aluminum-copper material joining by controlled dual laser beam

Abstract

Laser technology has many advantages in welding for the manufacture of EV battery packs. Aluminum (Al) and copper (Cu) are welded using a dual laser beam, suggesting the optimum power distribution for the core and ring beams. Due to the very high re ectance of Cu and Al exposed to near-infrared lasers, the material absorbs a very small amount of energy. Compared to single beam laser welding, dual beam welding has signi cantly improved surface quality by controlling surface solidi cation. The study focused on the quality of weld surface beads, weld properties and tensile strength by varying the output ratio of the core beam to the ring beam. Optimal conditions of Al6061 were a 700 W core beam, a 500 W ring beam and 200 mm/s of weld speed. For the C1020P, the optimum conditions were a center beam of 2500 W, a ring beam of 3000 W and a welding speed of 200 mm/s. In laser lap welding of Al-Al and Al-Cu, the bead width and the interfacial bead width of the joint increased as the output increased. The penetration depth did not change signi cantly, but small pores were formed at the interface of the junction. Tensile tests were performed to demonstrate the reliability of the weld zone, and computer simulations provided analysis of the heat distribution for optimal heat input conditions.

In-depth evaluation of micro-resistance spot welding for connecting tab to 18,650 Li-ion cells for electric vehicle battery application

“…1 shows a configuration of cylindrical cells to build the module from individual cells and several modules to build the pack. These tab-to-terminal connections demand efficient and cost-effective joining processes of which laser [6][7][8][9], micro-TIG [10] or resistance spot welding (RSW) [11,12] process can be used to weld a tab to the cell terminal. In general, the RSW is emerging as an attractive joining solution due to its low maintenance and investment cost as well as meets the market demands for low to medium volume applications, such as e-bikes, two-wheelers, or e-rickshaws [13].…”

Analysis of Laser Beam Modulation Effect on Aluminum and Copper Welding

“…In efforts to solve the problem, lasers have been operated in the double-beam or transverse mode [17][18][19][20]. Many studies have improved productivity and welding quality via real-time pre-heating, welding, or post-heating using these methods [6,10]. It is possible to increase the (low) absorption rates of di cultto-weld materials such as copper and aluminum, and to reduce pore formation and spattering [10,19].…”

“…Many studies have improved productivity and welding quality via real-time pre-heating, welding, or post-heating using these methods [6,10]. It is possible to increase the (low) absorption rates of di cultto-weld materials such as copper and aluminum, and to reduce pore formation and spattering [10,19]. However, it is di cult to study the (complex) uid behavior in the welding pool, since welding is rapid and the energy density is high.…”

“…It is di cult to obtain high-quality welds via general arc or electric-resistance welding. [1,[4][5][6][7][8][9][10].…”

“…Many studies have sought to counter this via preheating of the base material or heat treatment after welding. However, this adds cost, decreases productivity, and undesirable effects may develop in areas remote from the welds [10,16].…”