Fusion welding, specifically using electron beams or lasers, is the best method for welding battery components. Both electron beam and laser welding offer high power densities, pinpoint accuracy, and are well-suited for automated welding processes and small, miniature weld applications.
Depending on the project parameters, both laser welding and electron beam welding can be cost effective for battery arrays. However, battery array configurations are becoming more compact, and designs are continually evolving.
Brass (CuZn37) test samples are used for the quantitative comparison of the welding techniques, as this metal can be processed by all three welding techniques. At the end of the presented work, the suitability of resistance spot, ultrasonic and laser beam welding for connecting battery cells is evaluated.
Different welding processes are used depending on the design and requirements of each battery pack or module. Joints are also made to join the internal anode and cathode foils of battery cells, with ultrasonic welding (UW) being the preferred method for pouch cells.
“We see a lot of laser welding and ultrasonic wedge bonding for the larger packs,” says Boyle at Amada Weld Tech. “If the packs or the overall volume are smaller, then resistance welding is often used. Micro-TIG comes up for specialised battery packs with low-volume production.
“In these situations, cooperative development and reliable relationships are of high value.” While there many kinds of welding, in EV battery applications the most common are resistance welding and laser welding, along with ultrasonic welding and wire bonding, and benefit from standardisation for mass production.