Lithium Ion Heat Strips inside to keep battery at 32 degree F in cold weather and cut off at this temperater

Design a board with Thermostat which have thin 2 mm heat strips about 6 inch long , , This has its own small bottom batteries , but is tied to the batteries USB port to keep charged . One it hits 32 degree it cuts off . The batteries are E Bike Batteries 48v or 52v or 72v .