Microporous membrane separators for lithium ion rechargeable batteries and related methods
AssigneeCelgard, LLC
InventorsXiaomin Zhang, Kang Karen Xiao, Robert A. Nark, Ron E. Smith
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Abstract
In at least selected embodiments to novel or improved microporous battery separators for lithium rechargeable batteries and/or related methods of making and/or using such separators are disclosed. A particular inventive dry process battery separator or membrane separator exhibits a thickness that is less than about 14 μm and has increased strength performance as defined by reduced splittiness. The mode of splitting failure has been investigated, and the improvement in splittiness quantified by a novel test method known as the Composite Splittiness Index (CSI).
Claims10
A separator comprising:
- at least one microporous membrane being produced according to a dry stretch process in which a polyolefin resin mix containing polyolefin resin or blend containing the polyolefin resin is extruded to form said at least one microporous membrane, said polyolefin resin having a melt flow index (MFI) of less than or equal to 0.8 grams/10 minutes;
- and
- said separator having a total thickness of 7 μm, a puncture strength first load peak of 131 to 198 gf, and an electrical resistance (ER) value of less than or equal to 1.5 ohm-cm2.
A microporous polyolefin membrane comprising:
- at least one microporous membrane being produced according to a dry stretch process in which a polyolefin resin mix containing polyolefin resin or blend containing the polyolefin resin is extruded to form said at least one microporous membrane, said polyolefin resin having a melt flow index (MFI) of less than or equal to 0.8 grams/10 minutes;
- and
- said microporous membrane having a total thickness of 7 μm, a puncture strength first load peak of 131 to 198 gf, and an electrical resistance (ER) value of less than or equal to 1.5 ohm-cm2.
Dependencies are inferred from the claim text.