Can I use a battery bank to make a spot welder?
Fixing batteries with a spotwelder is frequently done with large capacitor banks. The capacitorbank solves two problems at the same time.


During spotwelding (for fixing a battery cell) a large to very large current is available.
In case something goes wrong (when fixing a battery cell) the large current is reduced to low when the capacitors are discharged.


With a large battery made of Li-Ion cells you would be able to reach target 1.

However when something goes wrong this battery would keep on supplying large currents. That would form a large risk in terms of fire hazard.
For me is therefore a DONT.