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.
Laser welding is widely used in lithium-ion batteries and manufacturing companies due to its high energy density and capability to join different materials. Welding quality plays a vital role in the durability and effectiveness of welding structures. Therefore, it is essential to monitor welding defects to ensure welds quality.
The counterpart has to be fixed but may have any thickness. It was reported that ultrasonic weld vibrations can damage the inside of a pouch cell, especially when the conductors inside the battery cell are also ultrasonically welded. In order to prevent the propagation of the vibrations into the cell, the terminal tabs need to be clamped .
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.
4.1.2 Effect on the battery cell Small-scale resistance welding is often the preferred method for joining Li–ion batteries into battery packs. This process ensures strong joints with an almost complete elimination of the heat impact on the joined workpieces during a short time.
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.