Patent ID: 11955662
Assignee: ASAHI KASEL KABUSHIKI KAISHA
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  B  Y | IPC B  H

Claim 0:
1. A separator for an electric storage device, comprising a microporous membrane comprising a polypropylene resin (A) and a thermoplastic elastomer (B), wherein the microporous membrane has the following regions:
(i) a polymeric matrix comprising the polypropylene resin (A) and the thermoplastic elastomer (B);
(ii) fibrils comprising the polypropylene resin (A) and extending in a Machine Direction (MD) of the microporous membrane from the polymeric matrix; and
(iii) pores between the fibrils; and
wherein a weight ratio of the polypropylene resin (A) to the thermoplastic elastomer (B) is 99.9:0.1 to 80:20,
wherein the region of the thermoplastic elastomer (B) is oriented along the MD of the microporous membrane, and
wherein a Melt Flow Rate (MFR) of the microporous membrane is 1.5 g/10 minutes or less, or wherein a Melt Flow Rate (MFR) of the polypropylene resin (A) is 1.0 g/10 minutes or less, or wherein the thermoplastic elastomer (B) forms a region in which a ratio (MD/TD) of a length in the MD to a length in a Transverse Direction (TD) is 1.5 or more and 10.0 or less;, and wherein the separator has a thickness from 11 to 16 μm, and
wherein a porosity of the microporous membrane is 37% or more and 51% or less.