That's why you don't touch Lithium Ion packs unless you know what you are doing. I've repaired many Bosch packs before I tried building my own and seeing the guts of professionally designed and robotically assembled packs after they're a few years old is a very sobering exercise in what to do and what definitely not to do.
There are a bunch of youtubers that go out of their way to give massively dangerous advice to people and I always wonder what their liability situation is.