Patent ID: 8304113
Filing Date: 2012-11-06
Classification: H01M,Y02E,Y02T

Abstract:
1. A method for manufacturing a separator for a lithium-ion battery with resistance to thermal runaway and without shutdown, the method comprising the steps of: (a) mixing a dry-blend comprising 40% by weight of a ultra high molecular weight polyethylene having an average molecular weight of 1×10 (b) feeding the dry-blend mixture into an extruder; (c) melt-kneading the dry blend mixture in the extruder while feeding 60% by weight of liquid paraffin into the dry blend mixture, creating a solution thereby; (d) extruding the solution into the form of a sheet; (e) cooling the sheet, thereby producing a gel sheet including the liquid paraffin; (f) extracting the liquid paraffin from the gel sheet and drying the gel sheet to form a dried gel sheet and retaining the calcined kaolin therein; (g) stretching the dried gel sheet in both directions to form a stretched gel sheet; and (h) heat setting the stretched gel sheet to form the separator having a melt integrity of at least 190° C., a puncture resistance of more than 550 grams, a tensile strength at 1000 psi of less than 2% offset and no shutdown temperature.