10–97% in nine minutes: BYD presents second generation of Blade Battery
electrive.com> charging powers of up to 1,500 kilowatts
> The Flash Chargers use their own energy storage systems to provide the extremely high charging power for short periods
This is common, Tesla and Electrify America use Tesla Megapacks across the US to shave peak demand for cost savings at many charger locations. BYD is simply doing it to juice the charge rate and smooth utility demand.
They really are crushing it on battery tech. Asianometry has a good video on the evolution: https://www.youtube.com/watch?v=iT72tMMBxVg