US 12,334,538 B2
Non-aqueous electrolyte secondary battery
Nobuhiro Sakitani, Tokushima (JP); and Takaharu Morikawa, Osaka (JP)
Assigned to PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD., Osaka (JP)
Appl. No. 17/267,969
Filed by Panasonic Intellectual Property Management Co., Ltd., Osaka (JP)
PCT Filed Aug. 1, 2019, PCT No. PCT/JP2019/030196
§ 371(c)(1), (2) Date Feb. 11, 2021,
PCT Pub. No. WO2020/044930, PCT Pub. Date Mar. 5, 2020.
Claims priority of application No. 2018-159821 (JP), filed on Aug. 29, 2018.
Prior Publication US 2021/0218014 A1, Jul. 15, 2021
Int. Cl. H01M 4/133 (2010.01); H01M 4/131 (2010.01); H01M 4/485 (2010.01); H01M 10/0525 (2010.01); H01M 10/0587 (2010.01)
CPC H01M 4/133 (2013.01) [H01M 4/131 (2013.01); H01M 4/485 (2013.01); H01M 10/0525 (2013.01); H01M 10/0587 (2013.01); H01M 2300/0017 (2013.01)] 3 Claims
OG exemplary drawing
 
1. A nonaqueous electrolyte secondary battery comprising: an electrode body in which a positive electrode plate and a negative electrode plate are wound with a separator interposed therebetween; and an exterior package which receives the electrode body,
wherein the negative electrode plate includes a negative electrode collector, a first negative electrode mixture layer formed on a winding inside first surface of the negative electrode collector, and a second negative electrode mixture layer formed on a winding outside second surface of the negative electrode collector,
the first negative electrode mixture layer contains first graphite particles as a primary component,
the second negative electrode mixture layer contains second graphite particles as a primary component, and
the first graphite particles has an internal void rate lower than an internal void rate of the second graphite particles,
wherein the internal void rate represents an average ratio of internal voids to a graphite particle,
the internal voids being enclosed within, and apart from a perimeter of, the graphite particle, wherein the internal void rate is calculated based on the following equation: (internal void rate of graphite particle)=(areas of internal voids of cross-section of graphite particle)/(cross-sectional area of graphite particle)×100(%), wherein the internal void rate of the first graphite particles is 5% or less, and the internal void rate of the second graphite particles is 8% to 20%.