Microporous polyolefin membrane and battery including same
AssigneeToray Industries, Inc.
InventorsAtsumichi Kawashima, Go Sato, Chunyao Li, Haruka Shimokawatoko
Life of this patent
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Abstract
To achieve an enhanced safety of a lithium ion battery while increasing the energy density and output of the battery, it is important to allow a separator to have a smaller maximum pore size, a higher pin puncture strength and a lower melt-heat shrinkage in the transverse direction. A polyolefin microporous membrane has a pin puncture strength per 20 μm of membrane thickness of 4.5 N or more, and contains a polyolefin, wherein the polyolefin has such a molecular weight distribution that the ratio of the polyolefin having a molecular weight of 5.0×106 or more is 0.6 to 1.5%.
Claims20
-9. (canceled)
A polyolefin microporous membrane having a pin puncture strength per 20 μm of membrane thickness of 4.5 N or more, and containing a polyolefin,
- wherein said polyolefin has such a molecular weight distribution that a ratio of the polyolefin having a molecular weight of 5.0×106 or more is 0.6 to 1.5%.
Dependencies are inferred from the claim text.