As a complete non-technical person, I have read the battery discussions with great interest. I drive a
Peugeot iOn and sit on top of the 16-kilowatt-hour (58 MJ) lithium-ion battery pack, which consists of 88 cells placed under the base floor. (Scroll down that link a bit for the section on "Battery").
I'm
very conscious of the assorted cooling fans and shutters that operate when charging, and when first driving off.
The battery has a forced air cooling system to prevent overheating during high charge and discharge rates and consequent damage. There is an integral fan in the battery pack. For rapid charging, the battery pack is additionally cooled with refrigerated air from the cars air conditioning system.