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US 2002/0165291 A1Published application
Battery separator
AssigneeKVG Technologies, Inc.
InventorWai Ming Choi
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AssigneeKVG Technologies, Inc.
InventorWai Ming Choi
Estimating the term…
A method for producing a battery separator is disclosed. The method comprises applying a coating of an ethylenically unsaturated monomer to the fibers of a non-woven sheet and polymerizing the monomer in situ on the fiber surfaces. The non-woven sheet is from 50 to 3000 microns thick, and is composed of polyolefin fibers having an average fiber diameter from 0.5 to 5 microns and a surface area from 0.2 to 30 square meters per gram. The ethylenically unsaturated monomer is polymerizable to a thermoplastic polymer which is hydrophilic as a consequence of containing COOH, OH, sulfonyl, sulfonic acid or carbonyl groups, or a monomer which has one of the following formulas: 1 In the foregoing formulas, R is an aliphatic or aromatic hydrocarbon group having from 2 to 8 carbon atoms, R4 is hydrogen or methyl, n is an integer from 2 to 15, and X+ is a cation selected from the group consisting of hydrogen, alkali metal cations, alkaline earth cations, cations of the transition metals Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn, and ammonium cations of the following formula: R5R6R7R8N+, each of R5R6, R7 and R8 is hydrogen, alkyl, alkenyl, cycloalkyl or cycloaklkenylene, and not more than one is a bivalent group bonded to N+ and by removing two hydrogens from an alkane, an alkene, a cycloalkane or a cycloalkene; the total number of carbons in R5 R6, R7 and R8does not exceed 21.
A method for producing a battery separator which comprises forming grafting sites on a non-woven sheet of polyolefin fibers by subjecting the sheet to glow discharge plasma, or to electron beam irradiation, contacting the resulting sheet with monomeric acrylic acid or another vinyl monomer capable of reacting with an acid or a base to form a salt directly or indirectly, and causing the acrylic acid or other vinyl monomer to react with the polyolefin fibers at the grafting sites by (1) irradiating the grafting sites on the polyolefin fibers with gamma or electron beam radiation while the monomeric acrylic acid or other vinyl monomer is in contact with the fiber surfaces, (2) irradiating the grafting sites on the polyolefin fibers with ultra violet light while the monomeric acrylic acid or other vinyl monomer is in contact with the fiber surfaces and the non-woven sheet is in an inert gas atmosphere, or (3) heating the polyolefin fibers while the monomeric acrylic acid or other vinyl monomer is in contact with the fiber surfaces.
A battery separator comprising at least one first layer of a fabric containing polyolefin fibers, from 20 percent to 80 percent by weight of which are dividable fibers composed of polypropylene segments and polyethylene segments, and from 10 percent by weight to 50 percent by weight of which are sheathcore fibers having a polypropylene core and a polyethylene sheath, with the proviso that the surfaces of the polyolefin fibers are hydrophilic as a consequence of exposure to plasma discharge in the presence of at least one of oxygen, nitrogen and argon, and at least one second layer which is a wetlaid or drylaid glass fiber sheet, a porous polymer film, a meltblown web of polymer fibers, a drylaid web composed of glass fibers and polymer fibers, a woven glass fiber web or a woven polymer fiber web, with the proviso that the layers of said separator are bonded together.
A method for producing a battery separator which comprises applying to the fibers of a non-woven sheet from 50 to 3000 microns thick of polyolefin fibers having an average fiber diameter from 0.2 to 30 microns and a surface area greater than 0.2 square meter per gram, a coating of an ethylenically unsaturated monomer which is polymerizable by addition polymerization to a thermoplastic polymer which is hydrophilic as a consequence of containing COOH, OH, sulfonyl, sulfonic acid or carbonyl groups, or a monomer which has one of the following formulas:
A lead acid battery comprising at least one positive plate, at least one negative plate, an anode, a cathode, electrical conductors operably connecting said plates, said anode and said cathode, and a battery separator produced by subjecting the fibers of a non-woven sheet from 50 to 3000 microns thick of polyolefin fibers having an average fiber diameter from 0.2 to 30 microns and a surface area from 01 to 20 square meters per gram to glow discharge to make the surfaces of the fibers hydrophilic.
A method for producing a battery separator which comprises forming grafting sites on a non-woven sheet of polyolefin fibers having an average fiber diameter in the range of 0.2 to 30 microns and a surface area of approximately 0.1 to 20 square meters per gram by treating the sheet with an electron beam, total dose 3 to 10 M rads, applying a monomeric solution of acrylic acid or of another vinyl monomer capable of reacting with an acid or a base to form a salt directly or indirectly, and causing the acrylic acid or other vinyl monomer to react with the polyolefin fibers at the grafting sites by (1) irradiating the grafting sites on the polyolefin fibers with gamma or electron beam radiation while the monomeric acrylic acid or other vinyl monomer is on the fiber surfaces or (2) irradiating the grafting sites on the polyolefin fibers with ultra violet light while the monomeric acrylic acid or other vinyl monomer is on the fiber surfaces and the non-woven sheet is in an inert gas atmosphere.
Dependencies are inferred from the claim text.