From what I understand, the cooling system in question may have done what it was designed to do - cool the battery's internal electronics - but it failed at protecting the battery from heat-related degradation. Hyundai supposedly used cold air blown into the pack, and that didn't work especially well either at keeping the cells cool.
Scarlet Ember 2018 Leaf SL W/ Pro Pilot
2009 Vectrix VX-1 W/18 Leaf modules, & 3 EZIP E-bicycles.
BAFX OBDII Dongle
PLEASE don't PM me with Leaf questions. Just post in the topic that seems most appropriate.