The search was then performed using Uppsala University’s Library database and Google scholar which cover a wide range of articles and sources. Three methods for welding batteries were given in the template, being laser beam-, ultrasonic-, and resistance spot welding.
The compared techniques are resistance spot welding, laser beam welding and ultrasonic welding. The performance was evaluated in terms of numerous factors such as production cost, degree of automation and weld quality. All three methods are tried and proven to function in the production of battery applications.
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.
The findings are applicable to all kinds of battery cell casings. Additionally, the three welding techniques are compared quantitatively in terms of ultimate tensile strength, heat input into a battery cell caused by the welding process, and electrical contact resistance.
The bonding interface eliminates metallurgical defects that commonly exist in most fusion welds such as porosity, hot-cracking, and bulk inter-metallic compounds. Therefore, it is often considered the best welding process for li-ion battery applications.
Moreover, the high-volume production requirements, meaning the high number of joints per module/BP, increase the absolute number of defects. The first part of this study focuses on associating the challenges of welding application in battery assembly with the key performance indicators of the joints.