The anodes are connected to the negative terminal and the cathodes to the positive terminal. The process and robustness of this joint are important to understand as welding the cell to busbars can damage the internal welds.
Challenges
- Trimming of tabs and avoiding any burrs or particles being left behind
- Gathering all of the foils and presenting them to the welder
- Aligning gathered electrode foils with tab
- Weld position alignment, whether that is Laser Alignment, spot weld or ultrasonic horn and anvil alignment
- Wear of electrodes / horn / anvil
- Consistent energy burst, energy oscillation, changes in materials or even surfaces
- Ensuring no sputter contaminates cell (see Cleaning Battery Terminals before Welding)
- Ensuring good consistent electrical connections
See also: Cylindrical Cell Joining Methods for a comparison of spot, laser and ultrasonic joining techniques used at pack level.