[markstos]

It does if the vape makers have an underpriced lithium source and don’t care about the pending lithium shortage.

[Scoundreller]

they're just buying off-the-shelf cylindrical or flat-pack li-ion cells

[folmar]

A popular theory is that they use "QC reject" grade, as the batteries often have arount 800 mAh capacity, two times less than most basic commercial grade.