US 12,148,918 B2
Positive electrode active material powder, positive electrode, lithium ion battery, and method of producing positive electrode
Keiichi Takahashi, Nishinomiya (JP); and Ryo Hanazaki, Kobe (JP)
Assigned to PRIME PLANET ENERGY & SOLUTIONS, INC., Tokyo (JP)
Filed by Prime Planet Energy & Solutions, Inc., Tokyo (JP)
Filed on Oct. 4, 2021, as Appl. No. 17/492,680.
Claims priority of application No. 2020-168291 (JP), filed on Oct. 5, 2020.
Prior Publication US 2022/0109141 A1, Apr. 7, 2022
Int. Cl. H01M 4/36 (2006.01); H01M 4/02 (2006.01); H01M 4/04 (2006.01); H01M 4/131 (2010.01); H01M 4/1391 (2010.01); H01M 4/505 (2010.01); H01M 4/525 (2010.01); H01M 4/66 (2006.01); H01M 10/0525 (2010.01)
CPC H01M 4/364 (2013.01) [H01M 4/0404 (2013.01); H01M 4/0435 (2013.01); H01M 4/131 (2013.01); H01M 4/1391 (2013.01); H01M 4/505 (2013.01); H01M 4/525 (2013.01); H01M 4/662 (2013.01); H01M 10/0525 (2013.01); H01M 2004/021 (2013.01); H01M 2004/028 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A positive electrode active material powder for a lithium ion battery, the positive electrode active material powder comprising:
a first particle group; and
a second particle group, wherein
the first particle group consists of a plurality of first particles,
each of the plurality of first particles includes 1 to 10 single-particles,
each of the single-particles has a first maximum diameter of more than or equal to 0.5 μm,
the first maximum diameter represents a distance between two most distant points on a contour line of the single-particle,
the second particle group consists of a plurality of second particles,
each of the plurality of second particles includes an aggregated particle,
the aggregated particle is formed by aggregation of 50 or more primary particles,
each of the primary particles has a second maximum diameter of less than 0.5 μm,
the second maximum diameter represents a distance between two most distant points on a contour line of the primary particle,
the positive electrode active material powder has a flow function coefficient of more than or equal to 2.9 and less than or equal to 5.1,
the flow function coefficient is a ratio of a maximum principal stress to a uniaxial collapse stress,
the uniaxial collapse stress and the maximum principal stress are measured by a direct shear test for powders,
the positive electrode active material powder has a water content of less than or equal to 970 ppm, and
a mass fraction of the first particle group with respect to a total of the first particle group and the second particle group is 20% to 75%.