Large-capacity lithium ion battery

The invention discloses a large-capacity lithium ion battery, which uses a more stable and mature connection process for a pole group and a shell cover, and simultaneously, uses an integrated shell cover to realize stable batch production and manufacturing of the large-capacity batteries. The large-capacity lithium ion battery disclosed by the invention comprises a battery shell, wherein a pole group is arranged in the battery shell; a battery cover is assembled at the upper part of the battery shell; the battery cover comprises a cover board, a separated shim, and a positive terminal and a negative terminal arranged on the cover board; the positive and negative terminals penetrate through an insulating washer and are fixed in a riveting mode together with a terminal press plate above theinsulating washer to the cover board and a positioning shim below the cover board; the separated shim is positioned on the cover board through a boss part below the terminals; a bursting disk and a protecting cover welded on