Rubber separators for tomorrow: performance characteristics and selection guide

A brief description is given of the basic differences in manufacturing processes and composition of the three types of rubber separator, namely: (i) sulfur-cured, hard rubber, ACE-SIL® separator; (ii) electron-beam crosslinked, FLEX-SIL® rubber separator; (iii) coated glass-mat MICROPOR-SIL® separator containing rubber. The physical, chemical, electrical and electrochemical properties of the three types of rubber separator are considered and the primary differences are explained. The beneficial performance characteristics found with rubber separators are presented, such as on-charge voltage characteristics, electrochemical compatibility for float-charging systems, retardation of antimony transfer, prevention of dendrite growth, and good wettability. Based on analysis of separator properties and battery requirements, a selection guide for rubber separators applicable to various types of lead/acid battery is compiled.