US 12,308,423 B2
Secondary cell
Shigeki Moriya, Osaka (JP); and Nobuhiro Sakitani, Tokushima (JP)
Assigned to PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD., Osaka (JP)
Appl. No. 17/438,253
Filed by Panasonic Intellectual Property Management Co., Ltd., Osaka (JP)
PCT Filed Mar. 6, 2020, PCT No. PCT/JP2020/009589
§ 371(c)(1), (2) Date Sep. 10, 2021,
PCT Pub. No. WO2020/189324, PCT Pub. Date Sep. 24, 2020.
Claims priority of application No. 2019-050158 (JP), filed on Mar. 18, 2019.
Prior Publication US 2022/0190323 A1, Jun. 16, 2022
Int. Cl. H01M 4/36 (2006.01); H01M 4/02 (2006.01); H01M 10/0587 (2010.01)
CPC H01M 4/366 (2013.01) [H01M 10/0587 (2013.01); H01M 2004/021 (2013.01); H01M 2004/028 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A secondary battery comprising a winding-type electrode assembly in which a positive electrode and a negative electrode are wound with a separator interposed therebetween, wherein
the positive electrode has a current collector, a first mixture layer formed on a first surface of the current collector facing the inside of the electrode assembly, and a second mixture layer formed on a second surface of the current collector facing the outside of the electrode assembly, and wherein
in the positive electrode, the first mixture layer includes a first active material, the second mixture layer includes a second active material, and an average surface roughness of the first active material is larger than an average surface roughness of the second active material,
wherein the average surface roughness of the first active material is 2.3% or more and 20% or less, and the average surface roughness of the second active material is 1% or more and 4.6% or less.