The YouTuber BigClive observed through dismantling many so-called disposable vape pens that they tend to have new, high quality, high amp cells, paired with decent or good charge controllers. He posited that this is to prevent them from going bang in people’s faces, which would be quite bad.
Around my area, I still find discarded vape pens in bike lanes or road shoulders, so I’m continuing to collect them. Although I never imagined stringing them together into a battery pack for an ebike haha
I can only hope that right-to-repair legislation in some US States and the EU will aid the situation, but it might still be a while.