Square battery cell, assembly method of square battery cell and battery module

The invention provides a square battery cell, an assembly method of the square battery cell and a battery module, and belongs to the technical field of new energy batteries. The square battery cell comprises a shell, a roll core package, an integrated pole and two side top cover assemblies, the shell comprises a top plate, a first rectangular side plate, a bottom plate and a second rectangular side plate. A mounting groove is formed in the plate surface of at least one end of the top plate, a through hole is formed in the mounting groove, and the roll core package is mounted in the shell. The integrated pole comprises a mounting block, a pole and a connecting piece, the connecting piece comprises a first connecting section and a second connecting section, the first connecting section is connected with the pole, and the second connecting section extends into the shell and is connected with the tab. Each side top cover assembly comprises a side cover and a plastic sealing piece, and the side covers of the two s