Electrodes are coated in standard widths up to around 1.5m. Hence, the next step is slitting. This stage runs along the length of the electrodes and cuts them down in width to match one of the final dimensions required for the cell.
It is really important that no burrs are created on the edges of the electrodes during this process as they can cause damage to the separator and a possible short-circuit at a later date.
When Comparing Slitting Methods it is important to consider:
Even with solid-state batteries and LFP, cutting burrs and delamination can lead to performance degradation and cell safety issues over lifetime.
A strict quality comparison based on the actual situation when multiple strips (4 or more) are being cut.
Ability to adapt to extremely difficult situations by eliminating both cutting burrs and delamination.
Challenges
- Avoiding burrs on edges
- Insulation tape may be applied here to mitigate foil to foil shorts from burrs
- Ensuring no loose metallic particles contaminate coatings
Control
Slitter Cutting Control Parameters
There are basically three slitter cutting control parameters for the shear cut method, which uses the same principle as scissors.
Quality
Slitter Burrs, Waviness and Delamination
Burrs and wavy edges on cell electrodes can have serious consequences up to and including an internal short-circuit and thermal runaway. Hence it is important to understand the slitting process and under what conditions burrs and waviness occurs.
See also: Calendering