That 100Wh is per-battery. Qantas here in Australia allows 20 batteries of up to 100Wh in carrion luggage.
"carrion luggage" lol
Did you get auto-incorrected?
No, that's just Australia. They have separate luggage limits for game animals.
Because this can involve portable refrigeration, people realized you could use this just for batteries.
Indeed, but here since you disassemble it, it's no longer a "battery", just cells, which are not regulated the same since when they are disconnected they are mostly passive