Thinking of how the MNT Reform designed their battery solution[0], I wonder if it's possible to build a "battery enclosure" where you can just drop in a bunch of LiFePo4 cells, so you can just purchase commodity batteries. It seems super wasteful to buy a complete new battery every time because it's just the cells inside that lose energy capacity...

[0] https://mntre.com/reform2/handbook/parts.html#battery-packs