After removal of the nickel strips, there remains (depending on the strongness of the weld and nickel thickness) some nickel chips :
On solderless Gouach batteries, this can lead to bad contact between the solder bead and the cell.
When is it needed to clean cells ?
As can be seen on the photos, the chips can be very close to the center, where the solder bead on the contact plate is situated. This can make for a very ponctual / intermittent contact
WIP
At which step must cells be cleaned ?
We can clean the cells right at the removal from the pack, or alternatively, before testing them
Safety
Protection equipment is mandatory :
Gloves (protecting against shirt circuit sparks and razor-cutting chips)
Protection goggles
Fire-safe cell disposal bin with extinguisher within easy reach
Sand bucket ? SDpack damaged cell box ? TBD
Dedicated machine
Thoughput: about 6s per cell
Results:
Slow motion:
Cutting
Using flush cutters
Caution : short circuit on the + side
Does shortening the cutters reduce the risk ?
Hammering
Flattening the chips seems to be sufficient in our application
“Plasma cleaning is a kind of dry cleaning, which relies on the "activation" of active ions in plasma to achieve the purpose of removing stains on the surface of objects. This method can effectively remove dirt, dust, etc. from the end face of the cell pole, and prepare for battery welding in advance to reduce defective soldering.”
Does not remove nickel strip chips
17/11/22
Potential problem:
Some nickel can get stuck on the positive side
It could them be releasing in the battery
Good conformal coating is mandatory
Cell cleaning with high pressure air?
Vacuum cleaner on + side once in the box?
X-Ray optical inspection?
Cutting machine needs adjustment for each cell welding pattern…
