Battery cell, battery module and manufacturing method of battery cell

The invention relates to the technical field of batteries, and discloses a battery cell, a battery module and a manufacturing method of the battery cell. The battery cell comprises an aluminum shell, a core package and a cathode connecting piece, two opposite ends of the aluminum shell are respectively connected with a cathode top cover and an anode top cover, the cathode top cover comprises a cathode top cover body and a cathode terminal, and the anode top cover comprises an anode top cover body and an anode terminal. A positive pole lug and a negative pole lug respectively extend out of two opposite sides of the core package along the width direction, and the positive pole lug is electrically connected with the positive terminal; and the negative connecting piece is connected with the negative tab through rolling welding, and one end of the negative connecting piece is connected with the negative terminal, so that a conductive path is integrally formed, and the battery cell can realize charging and discharg