Several components of lithium-ion batteries - electrode metal foils (current collectors), tabs and output terminals - are welded together using technologies such as laser or ultrasonic welding. If these welds are inadequate, the electrical resistance between components will increase.
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.
Particular relevant features of battery cells are welds for the internal electrical contact. Failures of these welds are often the cause for battery defects in the field and scrap during production. Consequently, there is a strong need to evaluate all welds during manufacturing.
In weld quality testing, resistance values between components are measured to ensure weld quality. Weld quality testing is carried out in every process that involves welding, including welding of electrode sheet tabs as well as welding between collectors and output terminals.
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.
Hence, the weld would not cause any significant resistance heating of the battery during charge or discharge . 4.3.2 Effect on the battery cell High currents must flow through the welds between battery cells in order to deliver the electricity needed to power a battery electric vehicle. These welds are the bottleneck of the electric circuit.