US 12,087,903 B2
Separator for electricity storage devices, and electricity storage device
Masato Murakami, Tokyo (JP); Shintaro Inaba, Tokyo (JP); Shinya Hisamitsu, Tokyo (JP); Daisuke Inagaki, Tokyo (JP); and Hiroshi Hatayama, Tokyo (JP)
Assigned to Asahi Kasei Kabushiki Kaisha, Tokyo (JP)
Filed by Asahi Kasei Kabushiki Kaisha, Tokyo (JP)
Filed on Dec. 30, 2021, as Appl. No. 17/565,607.
Application 17/565,607 is a division of application No. 16/489,072, granted, now 11,784,343, previously published as PCT/JP2018/041748, filed on Nov. 9, 2018.
Claims priority of application No. 2017-217832 (JP), filed on Nov. 10, 2017.
Prior Publication US 2022/0123432 A1, Apr. 21, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. H01M 10/0525 (2010.01); H01M 50/417 (2021.01); H01M 50/489 (2021.01); H01M 50/491 (2021.01)
CPC H01M 10/0525 (2013.01) [H01M 50/417 (2021.01); H01M 50/491 (2021.01); H01M 50/489 (2021.01)] 13 Claims
 
1. A separator configured for a lithium-ion secondary battery, which has a porous layer comprising a mixture of a polyolefin resin and an ionic compound, wherein a content of the ionic compound in the porous layer is 5% by weight or more and less than 50% by weight in the porous layer and a degree of whiteness of the separator is greater than 98.0, and the degree of whiteness is measured using a colorimeter under a condition that does not include a specular reflection light in a 2° viewing angle, and
wherein a viscosity-average molecular weight of the polyolefin resin comprised in the separator configured for a lithium-ion secondary battery is 300,000 or more and 5,000,000 or less.