BATTERY SYSTEM WITH THERMAL CONTROL LOOP

A battery cell system includes a plurality of battery cells having an annular shape abutting one another to form a battery cell stack with an annular shape to facilitate cooling. The battery cell system includes a stack interface having an annular housing operatively connected to the plurality of battery cells. A cooling loop is defined about the battery cell stack and the stack interface and through central through holes of the battery cell stack and the stack interface.