An overview of the manufacturing processes and performance requirements of nonwoven separators used in primary and secondary alkaline battery systems is presented. The systems described are alkaline manganese (Alk-Mn), nickel-cadmium (NiCd), nickel-metal-hydride (NiMH), nickel-zinc (NiZn), and zinc-air batteries. The separators used in these systems consist totally or partially of nonwoven materials. Accordingly, the paper starts with an overview of the typical methods of nonwoven production (web formation, bonding, and post-treatment) and how the products behave within the different battery systems. The paper then discusses the advantages and disadvantages of the different nonwoven products as battery separators in the various electrochemical systems. (c) 2007 The Electrochemical Society.