At some point, the 3.6 V of a single lithium ion battery just won’t do, and you’ll absolutely want to stack LiIon cells in series ... with packs like ebike batteries. What does 52 V represent?

For LiIon packs where multiple cells are connected in series, you’ll want a protection ... This is a lot more of a concern for LiPo pouch batteries than LiIon cells. Not that bending a LiIon ...