I misspoke, what I intended to say is that lithium ion batteries are never going to be user swappable. Yes, you can get sketchy stuff off of Amazon that support

I misspoke, what I intended to say is that lithium ion batteries are never going to be user swappable. Yes, you can get sketchy stuff off of Amazon that supports it, but the regulatory bodies will, correctly, continue to strongly resist end users touching bare lithium ion cells. Ever drop an AA battery? Nothing happens. Drop an 18650, you can easily have a little 1000 degree rocket shooting fire and toxic chemicals out one end. Nominal cell voltage is fairly standard and is dictated by cell chemistry. Standardized connector is welded zinc tab, for various good safety reasons.