A battery pack and a method of assembling a battery pack. The battery pack may include an outer housing; a cell module supportable by the outer housing, the cell module including a module housing, a plurality of battery cells supported by the module housing, the battery cells having an energy of at least about 60 Watt-hours, a controller operable to control an operation of the battery pack, a conductive strap electrically connected to at least one of the battery cells, a weld strap connected between the controller and the conductive strap, and a terminal electrically connected to the battery cells and operable to connect the battery cells to an electrical device for power transfer; and a vapor-deposited, hydrophobic nano coating applied to at least a portion of the cell module.