US 12,266,784 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. 22, 2020, as Appl. No. 17/130,840.
Claims priority of application No. 2019-236890 (JP), filed on Dec. 26, 2019.
Prior Publication US 2021/0202933 A1, Jul. 1, 2021
Int. Cl. H01M 4/36 (2006.01); H01M 4/02 (2006.01); H01M 4/133 (2010.01); H01M 4/134 (2010.01); H01M 4/583 (2010.01)
CPC H01M 4/364 (2013.01) [H01M 4/133 (2013.01); H01M 4/134 (2013.01); H01M 4/583 (2013.01); H01M 2004/027 (2013.01); H01M 2004/028 (2013.01)] 5 Claims
OG exemplary drawing
 
1. A negative electrode for a nonaqueous electrolyte secondary battery, comprising:
a negative electrode core body; and
a negative electrode mixture layer provided on a surface of the negative electrode core body,
wherein the negative electrode mixture layer includes graphite and fibrous carbon including single wall fibrous carbon and multiwalled fibrous carbon, and
wherein 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 body 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 body 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,
the first region includes the single wall fibrous carbon and the multiwalled fibrous carbon, and includes the single wall fibrous carbon in greater quantity than the multiwalled fibrous carbon in terms of mass and the second region includes the single wall fibrous carbon and the multiwalled fibrous carbon, and includes the multiwalled fibrous carbon in greater quantity than the single wall fibrous carbon in terms of mass, and
the negative electrode mixture layer includes an Si based active material containing Si, and the Si based active material is included in greater quantity in the second region than in the first region.