Methods of and apparatus for removing heat generated by cells of a battery pack. The methods and apparatus may employ one or more fan modules disposed between or next to cells of the battery pack, or one or more fans directly mounted to the battery pack or battery pack case housing the cells. Further, a motor controller isolation system operates to electrically isolate the motor controller of the electric vehicle when the battery pack is being charged. The motor controller isolation system may be integrated with the integrated battery pack and thermal and ventilation system. The integrated system, or “integrated battery unit (IBU),” is preferably manufactured in a manner that requires no, modifications to the electric vehicle in which the IBU is installed.