Aspects of the present disclosure involve various battery packs. In general, the battery pack includes a plurality of layers and an enclosure enclosing the plurality of layers. A cathode terminal and an anode terminal extend from a first face of the enclosure. The cathode terminal and the anode terminal are connected to the plurality of layers. A Parylene coating may cover an entire surface of the enclosure except for at least a portion of a surface of the first face.