US 12,334,590 B2
Nonaqueous electrolyte secondary battery separator, nonaqueous electrolyte secondary battery member, and nonaqueous electrolyte secondary battery
Akinori Bando, Ichihara (JP); Daisuke Yamaguchi, Ichihara (JP); Atsuhiro Takata, Osaka (JP); and Yuki Yoneguchi, Niihama (JP)
Assigned to SUMITOMO CHEMICAL COMPANY, LIMITED, Tokyo (JP)
Filed by Sumitomo Chemical Company, Limited, Tokyo (JP)
Filed on Mar. 29, 2022, as Appl. No. 17/706,701.
Claims priority of application No. 2021-058381 (JP), filed on Mar. 30, 2021.
Prior Publication US 2022/0328935 A1, Oct. 13, 2022
Int. Cl. H01M 50/494 (2021.01); H01M 50/417 (2021.01); H01M 50/423 (2021.01); H01M 50/449 (2021.01); H01M 50/491 (2021.01)
CPC H01M 50/494 (2021.01) [H01M 50/417 (2021.01); H01M 50/423 (2021.01); H01M 50/449 (2021.01); H01M 50/491 (2021.01)] 7 Claims
OG exemplary drawing
 
1. A nonaqueous electrolyte secondary battery separator comprising:
a polyolefin porous film,
the polyolefin porous film satisfying any one or more of the following conditions (1) and (2):
(1) a full width W at half maximum of a peak of an MD component is not less than 30 degrees, the full width W at half maximum of the peak being calculated from an azimuthal profile of a scattering peak on a (110) plane obtained by wide-angle X-ray scattering measurement that is carried out by irradiating a surface of the polyolefin porous film with an X-ray from a direction vertical to the surface of the polyolefin porous film, wherein, assuming that, in the azimuthal profile, a peak height is a difference between a maximum scattering intensity of a peak observed in a TD and a minimum scattering intensity of a valley which is adjacent to the peak and has a lowest intensity, the full width W at half maximum of the peak is a width of the peak at a scattering intensity at which the peak height is halved; and
(2) a maximum-to-minimum intensity ratio r is not more than 3.6 in a Fourier transformed azimuthal profile obtained by observing the surface of the polyolefin porous film by a scanning electron microscope, wherein the maximum-to-minimum intensity ratio r is calculated, with use of a maximum value Imax1 and a minimum value Imin1 in a range of 45 degrees to 135 degrees and a maximum value Imax2 and a minimum value Imin2 in a range of 135 degrees to 225 degrees in the Fourier transformed azimuthal profile, by the following formula (A):
r=(Imax1/Imin1+Imax2/Imin2)/2  (A).