US 12,407,067 B2
Separator and nonaqueous electrolyte secondary battery
Ichiro Arise, Osaka (JP); and Saki Morizane, Niihama (JP)
Assigned to SUMITOMO CHEMICAL COMPANY, LIMITED, Tokyo (JP)
Filed by Sumitomo Chemical Company, Limited, Tokyo (JP)
Filed on Mar. 18, 2022, as Appl. No. 17/698,021.
Claims priority of application No. 2021-046209 (JP), filed on Mar. 19, 2021; and application No. 2022-027138 (JP), filed on Feb. 24, 2022.
Prior Publication US 2022/0302552 A1, Sep. 22, 2022
Int. Cl. H01M 50/417 (2021.01); H01M 50/489 (2021.01)
CPC H01M 50/417 (2021.01) 8 Claims
 
1. A nonaqueous electrolyte secondary battery separator, wherein
the separator is a laminated separator comprising a porous layer and a polyolefin porous film,
when unevenness data of at least one surface of the porous layer of the separator is analyzed,
kurtosis of a data group of heights from a reference level is not less than 5, the kurtosis of the data group indicating a distribution curve sharper than a normal distribution curve when the kurtosis is not less than 0, and the kurtosis that is larger indicating a sharper distribution curve, and
standard deviation of the data group of the heights from the reference level is not more than 12.