Which welding techniques can be used for connecting battery cells?

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.

Can a battery cell casing be welded?

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.

How does welding energy affect electrical contact resistance and tensile force?

Further increasing the welding energy leads to electrode sticking and significant expulsion of bulk material , , , . Fig. 6. Electrical contact resistance and ultimate tensile force as function of welding energy.

Do voids inside the weld Nuggets reduce the strength of a joint?

The voids inside the weld nuggets for spot-welded CuZn37 test samples reduce the strength of the joint. But for spot-welded Hilumin test samples the base material failed and not the weld spots themselves (see Fig. 6). This was only observed with resistance spot welding.

Is there a quality assurance approach for laser welding?

Of course, if someone looks beyond the battery welding applications many in-process quality assurance approaches are available for welding . In the case of laser welding, the in- process monitoring is mainly based on imaging, acoustic emission, and E/M signal techniques in general .

Can laser beam welding reduce electrical contact resistance?

The optimal weld seam can be realized by laser beam welding resulting in relatively low electrical contact resistances. For the investigations shown in Fig. 14 the laser weld seam was modified from four independent weld seams each 2 mm long to two weld seams each 13.5 mm long.