Abstract: This disclosure relates to battery separators for use in lead acid batteries. In particular, the disclosure relates to nonporous polymer sheets in which the porosity manifests itself after cavitation and/or biaxial stretching to form a microporous membrane. The disclosure also relates to nonporous polymer sheets in which the porosity manifests itself after dissolution of an acid soluble filler to form a microporous membrane. In addition to meeting all battery performance requirements, these microporous membranes eliminate environmental and health concerns because they do not require the use of an organic solvent during their production.

Abstract: A polymer fiber sheet exhibits high porosity and good tensile properties in both “wet” and “dry” states. A fiber modifying agent is incorporated into a polymer extrusion and fiber formation process to produce a highly porous polymer fiber sheet that is instantaneously wettable by an aqueous medium. The fiber modifying agent functions as either one or both (1) a plasticizer that reduces the polymer extrudate melt viscosity and allows the formation of fine fibers during processing and (2) a surface modifying agent that promotes the instantaneous and sustainable wettability of individual polymer fibers and a porous fiber sheet formed from them. The polymer fiber sheet maintains its wettability even after repeated washing and drying cycles. The resultant fiber sheet can be densified and embossed to provide a desired thickness and porosity, while at the same time longitudinal ribs with desired pattern can also be formed on the fiber sheet.

Abstract: A multi-row melt-blown fiber spinneret (8) enables stacking rows (121, 122, 123) of polymer outlet orifices (36) more closely together than is achievable with conventional melt-blown fiber spinnerets. The fiber spinneret configuration also enables dense side-by-side packing of the polymer outlet orifices. The fiber spinneret is configured so that air knife channels (141c, 142c, 143c, 144c) and individual intricate small air knife passage feeds, together with their associated melt flow channels (501, 502, 503), are formed in the same body member. The rows of polymer outlet orifices are supplied with a polymer melt by a single polymer inlet (20), which delivers the polymer melt to the individual polymer melt flow channels. The air knife channels are directed through the body member, in which the polymer melt flow channels are formed by islands and air flow passage feeds. The body member is constructed by operation of a 3D printer for direct metal printing.

Abstract: A lead-acid battery separator with ultralow resistivity results from high porosity, controlled pore (10) size distribution, and an ionic surfactant (14) with a long alkyl side chain (18) that is anchored to the polymer matrix (12) of a silica-filled polyethylene separator. The surfactant cannot be easily removed or washed away and thereby imparts sustained wettability to the separator. Controlling the number of, and volume occupied by, the pores (i.e., porosity) and pore size distribution of the separator contributes to a reduction in electrical (ionic) resistivity.

Abstract: A polymer fiber sheet exhibits high porosity and good tensile properties in both “wet” and “dry” states. A fiber modifying agent is incorporated into a polymer extrusion and fiber formation process to produce a highly porous polymer fiber sheet that is instantaneously wettable by an aqueous medium. The fiber modifying agent functions as either one or both (1) a plasticizer that reduces the polymer extrudate melt viscosity and allows the formation of fine fibers during processing and (2) a surface modifying agent that promotes the instantaneous and sustainable wettability of individual polymer fibers and a porous fiber sheet formed from them. The polymer fiber sheet maintains its wettability even after repeated washing and drying cycles. The resultant fiber sheet can be densified and embossed to provide a desired thickness and porosity, while at the same time longitudinal ribs with desired pattern can also be formed on the fiber sheet.

Abstract: A lead-acid battery separator with ultralow resistivity results from high porosity, controlled pore (10) size distribution, and an ionic surfactant (14) with a long alkyl side chain (18) that is anchored to the polymer matrix (12) of a silica-filled polyethylene separator. The surfactant cannot be easily removed or washed away and thereby imparts sustained wettability to the separator. Controlling the number of, and volume occupied by, the pores (i.e., porosity) and pore size distribution of the separator contributes to a reduction in electrical (ionic) resistivity.

Abstract: A microporous silica-filled polyolefin separator (80) has a material composition that includes a fraction of cured rubber powder exhibiting low or no porosity. The cured rubber powder is a material derived from one or both of passenger and truck tires. The cured rubber powders exhibit the properties of increasing hydrogen evolution overpotential on the negative lead electrode and of decreasing the effect of antimony deposited on the negative electrode of the lead-acid battery. Incorporation of these cured rubber powders into the formulation of a microporous silica-filled polyethylene separator results in improved electrochemical properties in deep-cycle lead-acid batteries.

Abstract: A method of making a rubber-containing polyolefin separator entails preparing a pre-mixture (18) that includes polyolefin material (1), silica (2), and processing oil (5) and delivering the pre-mixture to a multi-zone extruder (12) having a sheet die (34). The pre-mixture becomes partly gelled as it advances in the extruder. Rubber powder (6) added at a medial zone (Z4) of the extruder combines with the pre-mixture advancing in the extruder to form a gelled rubber-containing extrudate as it exits the sheet die. The extrudate is processed by extracting a portion of the processing oil to form a separator sheet with dispersed rubber powder in the form of domains of larger average size. The larger rubber domains exhibit a smaller average ratio of surface area to volume and thereby results in slower release by diffusion of the beneficial substance from the rubber domains to the battery electrolyte.

Abstract: A microporous polyethylene battery separator material (212), for use in a flooded-cell type lead-acid battery, benefits from increased porosity, enhanced wettability, and exceptionally low electrical resistance when an electrolyte-soluble pore former is employed in the manufacturing process. The pore former (210) is soluble in electrolytic fluid and therefore dissolves in-situ in sulfuric acid during battery assembly. The dissolution of the pore former leaves behind additional, larger voids (220) in the separator material and thereby enhances ionic diffusion and improves battery performance.

Abstract: A microporous silica-filled polyolefin separator (80) has a material composition that includes a fraction of cured rubber powder exhibiting low or no porosity. The cured rubber powder is a material derived from one or both of passenger and truck tires. The cured rubber powders exhibit the properties of increasing hydrogen evolution overpotential on the negative lead electrode and of decreasing the effect of antimony deposited on the negative electrode of the lead-acid battery. Incorporation of these cured rubber powders into the formulation of a microporous silica-filled polyethylene separator results in improved electrochemical properties in deep-cycle lead-acid batteries.

Abstract: A microporous polyethylene battery separator material (212), for use in a flooded-cell type lead-acid battery, benefits from increased porosity, enhanced wettability, and exceptionally low electrical resistance when an electrolyte-soluble pore former is employed in the manufacturing process. The pore former (210) is soluble in electrolytic fluid and therefore dissolves in-situ in sulfuric acid during battery assembly. The dissolution of the pore former leaves behind additional, larger voids (220) in the separator material and thereby enhances ionic diffusion and improves battery performance.