A simple solution would be to warm the battery to a reasonable temperature but I don't know if that's feasible for such a large battery. It's not as easy as keeping a phone in an inside pocket vs an outside one. The car should be built with heaters around the battery. The power must come from the charger at charge time (but maybe the battery self warms itself while charging,) then from the battery. What's more: power for the heaters or power to move the car? Probably the latter.