No idea. Surely there’s heat sinks & fans as needed. (That battery pack is HEAVY. My cute spunky little Leaf weighed nearly 2 tons.)
I kinda wondered about the heat problem when I was recently at my local Walmart. They have two EV charging stations and I happened to look at the meter and was amazed to see the attached Nissan Leaf taking on 391 Volts! I didn’t ask the guy who was sitting in the car if we could open the battery compartment and feel the battery! I figure if there is excessive heat during a charge with that much voltage, the battery life might be shortened.
I’ve heard that the Leaf battery weighs 900 pounds.