Patent ID: 7981549

Claim:
A battery separator for a nickel-zinc battery comprising: a microporous membrane comprising a microporous hydrophobic, polyolefinic polymer film having a thickness of less than 1.5 mils and having an effective average pore size of less than 0.045 micron; and a coating of cellulose acetate and a surfactant combination on at least one surface of said membrane and having a surface density in the range of 0.30 to 0.43 mg/cm 2 , said coating comprising a mixture of 25-40 weight % of the cellulose acetate and 60-75 weight % of the surfactant combination comprising a first surfactant having an active ingredient selected from the group consisting of organic ethers and a second surfactant being an oxirane polymer with 2-ethylhexyl dihydrogen phosphate, said cellulose acetate having about 2.5 acetyl groups per glucose, and the separator having an electrical resistance of ≦21.6 mΩ-in 2 and being wetted within 3 seconds or less.