A heat exchanger integrated into an electric vehicle's battery pack enclosure is provided, where the heat exchanger conduits are mechanically and thermally coupled to the inside surface of the enclosure base plate and where the battery pack enclosure is mounted such that ambient air flows over the outside surface of the enclosure base plate during vehicle motion. A thermal management system is coupled to, and controls operation of, the integrated battery pack heat exchanger such that in a first operational mode the heat exchanger is thermally coupled to the batteries within the battery pack, and in a second operational mode the heat exchanger is thermally decoupled from the batteries within the battery pack.