US 12,444,747 B2
Method of producing non-aqueous electrolyte secondary battery, and negative electrode active material
Yuta Matsuo, Kobe (JP); Kaori Ishikawa, Nishinomiya (JP); Kunihiko Hayashi, Miki (JP); and Masumi Terauchi, Koriyama (JP)
Assigned to PRIME PLANET ENERGY & SOLUTIONS, INC., Tokyo (JP)
Filed by PRIME PLANET ENERGY & SOLUTIONS, INC., Tokyo (JP)
Filed on Feb. 24, 2022, as Appl. No. 17/679,607.
Claims priority of application No. 2021-038258 (JP), filed on Mar. 10, 2021.
Prior Publication US 2022/0293943 A1, Sep. 15, 2022
Int. Cl. H01M 4/587 (2010.01); H01M 4/02 (2006.01)
CPC H01M 4/587 (2013.01) [H01M 2004/021 (2013.01); H01M 2004/027 (2013.01)] 9 Claims
OG exemplary drawing
 
1. A method of producing a non-aqueous electrolyte secondary battery, comprising:
preparing a negative electrode active material by mixing a first graphite particle and a second graphite particle;
producing a negative electrode including the negative electrode active material; and
producing a non-aqueous electrolyte secondary battery including the negative electrode, a positive electrode, and an electrolyte solution, wherein
a blending ratio, M2/M1, of the second graphite particle to the first graphite particle is from 0.025 to 0.125, where M1 is a mass of the first graphite particle included in the negative electrode active material and where M2 is a mass of the second graphite particle included in the negative electrode active material,
the first graphite particle has a first number-based particle size distribution,
the second graphite particle has a second number-based particle size distribution, and
a relationship of an expression (I):
D250/D150≤0.50  (I)
is satisfied, where
D150 is a D50 in the first number-based particle size distribution, and
D250 is a D50 in the second number-based particle size distribution, and
relationships of expressions (II), (III) and (IV):
R2≤R1  (II)
0.94≤R1  (III)
0.90≤R2≤R1  (IV)
are satisfied, where
R1 is an arithmetic mean of circularity of the first graphite particle, and
R2 is an arithmetic mean of circularity of the second graphite particle.