US 12,095,118 B2
Secondary battery, battery pack, electric vehicle, electric power storage system, electric power tool, and electronic apparatus
Takaaki Matsui, Tokyo (JP); Kazuki Honda, Tokyo (JP); Rikako Imoto, Tokyo (JP); Hideki Nakai, Kyoto (JP); and Takashi Sato, Tokyo (JP)
Assigned to Murata Manufacturing Co., Ltd., Kyoto (JP)
Filed by MURATA MANUFACTURING CO., LTD., Kyoto (JP)
Filed on Feb. 9, 2021, as Appl. No. 17/171,509.
Application 17/171,509 is a continuation of application No. PCT/JP2019/016146, filed on Apr. 15, 2019.
Claims priority of application No. 2018-150509 (JP), filed on Aug. 9, 2018.
Prior Publication US 2021/0167470 A1, Jun. 3, 2021
Int. Cl. H01M 50/538 (2021.01); H01M 4/02 (2006.01); H01M 4/133 (2010.01); H01M 4/134 (2010.01); H01M 4/38 (2006.01); H01M 4/66 (2006.01); H01M 10/0525 (2010.01)
CPC H01M 50/538 (2021.01) [H01M 4/133 (2013.01); H01M 4/134 (2013.01); H01M 4/386 (2013.01); H01M 4/661 (2013.01); H01M 10/0525 (2013.01); H01M 2004/027 (2013.01); H01M 2004/028 (2013.01); H01M 2220/20 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A secondary battery comprising
a wound electrode body including a positive electrode, a negative electrode, and a separator, the positive electrode and the negative electrode being stacked on each other with the separator interposed therebetween and being wound with respect to a winding axis, wherein
the wound electrode body has a section perpendicular to the winding axis, the section having an elongated shape that includes a flat part and a pair of curved parts, the curved parts opposing each other with the flat part interposed therebetween,
the negative electrode includes a negative electrode current collector and a negative electrode active material layer provided on the negative electrode current collector, and
a width of the wound electrode body, a wound-layer number of the wound electrode body, and a ratio of a second distance to a first distance satisfy a Condition A,
wherein the first distance is a distance from one to another of two mutually adjacent parts of the negative electrode current collector in the flat part, and the second distance is a distance from one to another of two mutually adjacent parts of the negative electrode current collector in the curved parts,
wherein the Condition A includes:
the width of the wound electrode body is from 30 millimeters to 160 millimeters;
the wound-layer number of the wound electrode body is from 8 to 19; and
the ratio of the second distance to the first distance is from 0.930 to 0.989.