US 11,728,472 B2
Negative electrode for nonaqueous electrolyte secondary battery, and nonaqueous electrolyte secondary battery
Masanori Sugimori, Osaka (JP); Yusuke Fukumoto, Osaka (JP); Yuji Yokoyama, Hyogo (JP); Nobuhiro Hirano, Osaka (JP); and Yo Kato, Nagoya (JP)
Assigned to PANASONIC HOLDINGS CORPORATION, Osaka (JP); and TOYOTA JIDOSHA KABUSHIKI KAISHA, Toyota (JP)
Filed by Panasonic Corporation, Kadoma (JP); and TOYOTA JIDOSHA KABUSHIKI KAISHA, Toyota (JP)
Filed on Dec. 16, 2020, as Appl. No. 17/123,963.
Claims priority of application No. JP2019-231706 (JP), filed on Dec. 23, 2019.
Prior Publication US 2021/0193992 A1, Jun. 24, 2021
Int. Cl. H01M 4/62 (2006.01); H01M 4/133 (2010.01); H01M 4/583 (2010.01); H01M 4/36 (2006.01); H01M 10/0525 (2010.01); H01M 4/134 (2010.01); H01M 4/02 (2006.01)
CPC H01M 4/364 (2013.01) [H01M 4/133 (2013.01); H01M 4/134 (2013.01); H01M 4/366 (2013.01); H01M 10/0525 (2013.01); H01M 2004/021 (2013.01); H01M 2004/027 (2013.01)] 5 Claims
OG exemplary drawing
 
1. A negative electrode for a nonaqueous electrolyte secondary battery, comprising:
a negative electrode core sheet; and
a negative electrode mixture layer provided on a surface of the negative electrode core sheet,
wherein the negative electrode mixture layer includes graphite and fibrous carbon, and
wherein, when a range of 40% of a thickness of the mixture layer from a surface of the negative electrode mixture layer on a side opposite to the negative electrode core sheet is defined as a first region and a range of 40% of a thickness of the mixture layer from an interface between the negative electrode mixture layer and the negative electrode core sheet is defined as a second region,
a BET specific surface area of the graphite included in the first region is smaller than a BET specific surface area of the graphite included in the second region, and
an average length of the fibrous carbon included in the first region is longer than an average length of the fibrous carbon included in the second region, wherein the average length of the fibrous carbon included in the first region is 5 μm or more and less than 50 μm, and the average length of the fibrous carbon included in the second region is 0.05 μm or more and 4.5 μm or less.