The invention is suitable for the field of batteries, and discloses a method for manufacturing a lithium-ion secondary battery. An opening is formed in a cylindrical shell which is integrally formed, and one end of the cylindrical shell is closed and the other end of the cylindrical shell is open. The opening is formed in the closed end of the shell. A positive tab or a negative tab led out by a roll core is led out through the opening of the closed end of the shell to be welded with a metal cover plate, therefore the problems of low percent of pass and high cost of the battery with a cylindrical aluminum shell with two open ends in the prior art are solved, meanwhile the steel or aluminum shell with two open ends in the prior art can also be thinner, and therefore materials can be saved and the energy density is increased. Further, the problems of poor welding reliability and low production efficiency caused by the blind welding between the closed end of the shell in the prior art and the tab are also solved.