公开(公告)号：US20210210823A1

公开(公告)日：2021-07-08

申请号：US17059459

申请日：2019-05-17

Applicant: BYD COMPANY LIMITED

Inventor： Wansong YUAN ,  Yi PAN ,  Guihai LIANG ,  Fulan TANG

IPC: H01M50/536 ,  H01M10/0525 ,  H01M50/586 ,  H01M50/59

Abstract: An electrode assembly for a lithium-ion secondary battery and a preparation method thereof, and a lithium-ion secondary battery are disclosed. The electrode assembly comprises an electrode and an electrode post, where an electrode tab is extended from the electrode; a welding connection portion is formed by welding between the electrode tab and the electrode post; the welding connection portion has a bulge welding defect; the surface of the welding connection portion is covered with a polymer protective layer, and the thickness of the polymer protective layer is greater than or equal to the thickness of the bulge welding defect; and the bulge welding defect is embedded in the polymer protective layer.