C rating still applies, charging at 1C is usually "fast" charging for most cells and that takes an hour, charging in 5 minutes is is 12C which is normally "bad", would need lots of active cooling.

50kw would take 2 hours on a 100kwh pack so it would only be 0.5C. To do it in 5 minutes would require 1.2 megawatts of charge rate.

Good thing lots of EVs have active cooling systems for their battery packs. It doesn't just extend range, it increases charging rates as well.