US 11,757,085 B2
Nonaqueous electrolyte secondary battery
Yuji Yamamoto, Toyota (JP); Momoko Procter, Seto (JP); Yoshinari Makimura, Nisshin (JP); Tetsutaro Hayashi, Niihama (JP); and Willy Shun Kai Bong, Niihama (JP)
Assigned to TOYOTA JIDOSHA KABUSHIKI KAISHA, Toyota (JP); and SUMITOMO METAL MINING CO., LTD., Tokyo (JP)
Filed by TOYOTA JIDOSHA KABUSHIKI KAISHA, Toyota (JP); and SUMITOMO METAL MINING CO., LTD., Tokyo (JP)
Filed on Jul. 15, 2020, as Appl. No. 16/929,166.
Claims priority of application No. 2019-133130 (JP), filed on Jul. 18, 2019.
Prior Publication US 2021/0020901 A1, Jan. 21, 2021
Int. Cl. H01M 4/131 (2010.01); H01M 4/36 (2006.01); H01M 10/0525 (2010.01); H01M 4/525 (2010.01); H01M 4/485 (2010.01); H01M 4/505 (2010.01); H01M 4/1391 (2010.01); H01M 4/02 (2006.01)
CPC H01M 4/131 (2013.01) [H01M 4/1391 (2013.01); H01M 4/366 (2013.01); H01M 4/485 (2013.01); H01M 4/505 (2013.01); H01M 4/525 (2013.01); H01M 10/0525 (2013.01); H01M 2004/021 (2013.01); H01M 2004/027 (2013.01); H01M 2004/028 (2013.01)] 2 Claims
OG exemplary drawing
 
1. A nonaqueous electrolyte secondary battery, comprising:
a positive electrode;
a negative electrode; and
a nonaqueous electrolyte, wherein
the positive electrode includes a positive electrode active material layer,
the positive electrode active material layer contains a lithium nickel cobalt manganese composite oxide having a layered structure as a positive electrode active material,
the lithium composite oxide is in a form of porous particles,
each of the porous particles has at least two voids each of which has a percentage of a void area with respect to an area occupied by each of the particles in a cross-sectional view thereof of at least 1%, and
each of the porous particles is provided with a coating of lithium tungstate on a surface thereof,
wherein the porous particles have an average void ratio of at least 10% and not more than 50%, and a percentage of particles having a void ratio of at least 10% and not more than 50% in the porous particles is at least 80%,
wherein 4≤T/C≤6 is satisfied where T is a value of the compositional ratio of the lithium atom to a total of the nickel, cobalt, and manganese atoms contained in the lithium composite oxide and C is a value of a mass percentage of tungsten contained in the coating with respect to the lithium composite oxide, and
the lithium nickel cobalt manganese composite oxide is represented by the following formula (1):
LiaNixMnyCozO2  (1),
wherein, in formula (1), 1≤a≤1.4, x, y, and z satisfy x+y+z=1, 0.34≤x≤0.60, 0<y≤0.40, and 0<z≤0.40.