Oxidation protected separator
A battery separator for a lead/acid battery is resistant to oxidation arising from the use of water or acid containing contaminants, for example chromium (Cr), manganese (Mn), titanium (Ti), copper (Cu), and the like. The separator is a microporous membrane including a rubber. The rubber is no more than about 12% by weight of the separator. The rubber may be rubber latex, tire crumb, and combinations thereof. The rubber may be impregnated into the microporous membrane. The microporous membrane may be a microporous sheet of polyolefin, polyvinyl chloride, phenol-formaldehyde resins, cross-linked rubber, or nonwoven fibers. A method for preventing the oxidation and/or extending battery life of the separator is also included.
1. A separator suitable for use in a lead acid battery comprising a microporous membrane comprising a microporous sheet of polyolefin and about 6% rubber by weight of the separator, wherein the rubber is uniformly blended within the polyolefin and distributed throughout the microporous membrane; and wherein the separator exhibits at least 100% elongation without break after 700 hours of exposure to 4.5 to 4.7 ppm Cr in an elongation at break test procedure.
2. The separator of claim 1 , wherein the rubber is an uncross-linked or uncured rubber.
3. The separator of claim 2 , wherein the uncross-linked or uncured rubber is selected from the group consisting of rubber latex, tire crumb, and combinations thereof.
4. The separator of claim 2 , wherein the uncross-linked or uncured rubber is impregnated into the separator.
5. The separator of claim 2 , wherein the polyolefin is one or more of the group consisting of polyethylene, polypropylene, high molecular weight polyethylene (“HMWPE”), ultra-high molecular weight polyethylene (“UHMWPE”), and combinations thereof.
6. The separator of claim 5 , further comprising silica.
7. The separator of claim 1 , comprising a first set of ribs on a first surface, and a second set of ribs on a second surface.
8. The separator of claim 7 , wherein said first set of ribs are in a machine direction.
9. The separator of claim 8 , wherein said second set of ribs are in a cross-machine direction.
10. The separator of claim 1 , wherein said rubber is impregnated into the separator.
11. The separator of claim 1 , wherein the polyolefin is one or more of the group consisting of polyethylene, polypropylene, high molecular weight polyethylene (“HMWPE”), ultra-high molecular weight polyethylene (“UHMWPE”), and combinations thereof.
12. The separator of claim 11 , further comprising silica.
13. In a dry charge flooded lead acid battery, the improvement comprising the separator of claim 1 , wherein an electrolyte of the battery comprises one or more contaminants, said one or more contaminants being one or more selected from the group consisting of chromium, manganese, titanium, copper, and combinations thereof.
14. In a flooded lead acid battery, the improvement comprising the separator of claim 1 , wherein an electrolyte of the battery comprises one or more contaminants, said one or more contaminants being one or more selected from the group consisting of chromium, manganese, titanium, copper, and combinations thereof.