Embodiments provide a battery cell, a battery, an electric apparatus, and a manufacturing method and system of battery cell. In some embodiments, the battery cell includes a housing, an electrode assembly, and an end cover assembly. The housing provides an opening. The electrode assembly is disposed in the housing. The electrode assembly includes a body portion, a tab, and an isolation portion. The tab extends from an end of the body portion to the opening. The isolation portion is disposed on a periphery of the tab. The end cover assembly is configured to cover the opening. The end cover assembly includes an end cover and a first insulator. The end cover is configured to cover the opening and is connected to the housing. The first insulator is disposed on a side of the end cover proximate to an inside of the housing. The first insulator has a concave portion.