[mrexroad]

They do already :) Fwiw, Tesla already utilizes active (liquid) cooling as passive (air) cooling is insufficient even without insulation; further, air+liquid cooling is still not enough so refrigeration and heat exchanger is also used to remove thermal energy. Removing passive cooling and adding insulation would require refrigerated cooling to be used for a far greater percentage of time (more weight, more energy). It’s simply easier to heat the batts in cold than it is to cool them. Not to mention there’s worst case failure modes—too cold = dead batt, too hot = combustion.