Abstract: A method for manufacturing battery separators for use in a lithium-ion battery containing non-aqueous electrolytes, producing batteries being resistant to thermal runaway and explosion, includes the steps of preparing a dryblend comprising two UHMW Polyethylenes and Calcined Kaolin, feeding said dry-blend into an extruder, melt-kneading said dry blend in the extruder while feeding mineral oil, making a solution from a die into the form of a sheet, using casting rolls, thereby cooling the solution down, producing a thick gel sheet, stretching the gel sheet in both machine and transverse directions, producing a 20 micron thick gel sheet containing oil thereby, extracting the oil by use of a solvent and drying the film, heat-setting the film and producing a microporous membrane.

Abstract: A ceramic microporous polyolefin battery separator membrane, high in air permeability, low in shrinkage and improved temperature resistance addresses the safety requirements of lithium ion batteries. The separators made by the current invention consists of one or more polyolefin polymers and kaolin fillers comprised of aluminum oxide and silicon oxide. The membranes of current invention have a thickness of 5-200 microns, air permeability of 1-200 sec/10 cc (Gurley seconds), and average pore diameter of less than 1 micron.

Abstract: A method for manufacturing battery separators for use in a lithium-ion battery containing non-aqueous electrolytes, producing batteries being resistant to thermal runaway and explosion, includes the steps of preparing a dryblend comprising two UHMW Polyethylenes and Calcined Kaolin, feeding said dry-blend into an extruder, melt-kneading said dry blend in the extruder while feeding mineral oil, making a solution from a T-die into the form of a sheet, using casting rolls, thereby cooling the solution down, producing a thick gel sheet, stretching the gel sheet in both machine and transverse directions, producing a 20 micron thick gel sheet containing oil thereby, extracting the oil by use of a solvent and drying the film, heat-setting the film producing a microporous membrane.

Abstract: A ceramic microporous polyolefin battery separator membrane, high in air permeability, low in shrinkage and improved temperature resistance addresses the safety requirements of lithium ion batteries. The separators made by the current invention consists of one or more polyolefin polymers and kaolin fillers comprised of aluminum oxide and silicon oxide. The membranes of current invention have a thickness of 5-200 microns, air permeability of 1-200 sec/10 cc (Gurley seconds), and average pore diameter of less than 1 micron.

Abstract: A microporous polyolefin battery separator membrane is extremely high in porosity, high in puncture strength, very low in shrinkage and with shutdown temperature of 130-140 degrees C. and melt integrity greater than 165 degrees C. It consists of 20-30% by weight of a UHMW polyethylene having Mw of 1×106 or higher, 60-70% by weight of a HDPE having average Mw of between 200,000-500,000 and 5-15% by weight of TiO2 with an average particle size of less than 0.2 microns.

Abstract: A battery separator having sodium sulfate incorporated therein in order to reduce and/or eliminate hydration short problems in batteries. The preferred method of adding sodium sulfate directly to the separator is via the use of sodium sulfate-containing silica as a separator filler added during the process of manufacturing the separator. The present invention is also directed to a battery separator containing a relatively high level of sodium sulfate, and to batteries which incorporate such separators.