Low-cost, flexible battery packaging materials

The authors' approach to laminate construction consisted of using an aluminum foil and sealant film, and adding a second foil layer to limit moisture permeation and a tough polymer exterior barrier, typically oriented polyester. Although nylon is sometimes used in the packaging industry as the protective exterior layer, its high water-absorption rate could adversely affect the calendar life of lithium-based cells. So although nylon was tested, it was not included in the authors' final design.