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.

What is resistance spot welding?

Resistance spot, ultrasonic or laser beam welding are mostly used for connecting battery cells in the production of large battery assemblies. Each of these welding techniques has its own characteristics depending on the material properties and contact geometry. Cell casing and terminal dimensions may constrain possible contact geometries.

How a cell connection affects the performance of a battery system?

Every single cell connection influences the functionality and efficiency of the whole battery system. Resistance spot, ultrasonic or laser beam welding are mostly used for connecting battery cells in the production of large battery assemblies.

How is a thyristor used in a spot welding machine?

In an AC pulse spot welding machine, the thyristor is controlled by the single-chip microcomputer to intercept the AC pulse voltage for the primary coil of the welding transformer. The transformer then converts the high-voltage pulse into a low-voltage large current and outputs it to the spot welding needle for discharge spot welding.

Does ultrasonic welding cause damage to lithium ion cells?

The highest heat input occurred at ultrasonic welding, but for all welding techniques the heat was very localized and no damaging temperatures occurred at the lithium-ion cells. The results presented in this paper were gathered within the research project EEBatt, funded by the Bavarian Ministry of Economic Affairs and Media, Energy and Technology.