Laminated oxidation protected separator

Abstract

A battery separator for a lead acid battery addresses the issues of acid stratification and separator oxidation arising from contaminants. The separator includes a microporous membrane and a diffusive mat affixed thereto. The diffusive mat has a three hour wick of: at least about 2.5 cm. The diffusive mat may be made of synthetic fibers, glass fibers, natural fibers, and combinations thereof. The diffusive mat may include silica. The separator may include a rubber.

1 - 17 . (canceled) 
     
     
         18 . A battery separator for a flooded lead acid battery comprising:
 a microporous membrane made from a sheet of one or more selected from polyolefin, polyvinyl chloride, and phenol-formaldehyde resin, and   a diffusive mat affixed to the microporous membrane, said diffusive mat having an electrolyte wicking defined by a three hour wick of at least 2.5 cm, and   wherein the diffusive mat improves the flooded lead acid battery performance when compared to an equivalent flooded lead acid battery with a glass mat by inhibiting battery electrodes from drying out through wicking of free liquid electrolyte in the flooded lead acid battery and protecting against acid stratification by improved diffusion properties obtained from the electrolyte wicking.   
     
     
         19 . The separator flooded lead acid battery of  claim 18 , wherein said diffusive mat has a basis weight greater than about 35 gsm. 
     
     
         20 . The separator flooded lead acid battery of  claim 18 , wherein said diffusive mat is made of synthetic fibers, glass fibers, or a combination of both. 
     
     
         21 . The separator flooded lead acid battery of  claim 18  wherein said diffusive mat has an MD stiffness of greater than about 90 mN, and a CMD stiffness of greater than about 45 mN. 
     
     
         22 . The separator flooded lead acid battery of  claim 18 , wherein said diffusive mat comprises particulate silica. 
     
     
         23 . The separator flooded lead acid battery of  claim 18  wherein the microporous membrane is impregnated with uncured rubber. 
     
     
         24 . The separator of  claim 23 , wherein said uncured rubber comprises no more than 12% by weight of the separator. 
     
     
         25 . The separator flooded lead acid battery of  claim 24 , wherein said uncured rubber comprises 2.5-3.5% by weight of the separator. 
     
     
         26 . The separator of  claim 23 , wherein said uncured rubber is a natural latex. 
     
     
         27 . The separator of  claim 23 , wherein said uncured rubber is a synthetic latex. 
     
     
         28 . The separator of  claim 23 , wherein said uncured rubber is a natural rubber. 
     
     
         29 . The separator of  claim 18 , wherein said microporous membrane is made from a microporous sheet of polyolefin. 
     
     
         30 . The separator of  claim 18  wherein said diffusive mat comprises fine glass fibers. 
     
     
         31 . The separator of  claim 18  wherein said diffusive mat comprises a natural fiber. 
     
     
         15 . The separator of  claim 18 , wherein the diffusive mat has a thickness greater than 0.2 mm. 
     
     
         32 . The separator of  claim 18 , wherein the diffusive mat has a thickness from 0.2 mm to 0.5 mm. 
     
     
         33 . A flooded lead acid battery comprising the separator of  claim 18 . 
     
     
         34 . The flooded lead acid battery of  claim 33 , the battery being selected from inverter batteries, enhanced flood batteries (EFB), ISS batteries, stationary batteries, or golf cart batteries.