Secondary Battery and Method for Manufacturing the Same

To solve the above-described objects, a method for manufacturing a secondary battery according to an embodiment of the present invention comprises: manufacturing an electrode assembly in which electrodes and a separator are alternately stacked; inserting the electrode assembly into a battery case through an opening; covering the opening of the battery case; injecting an electrolyte into the battery case through an injection hole formed in the battery case; closing the injection hole; performing a pre-formation process; and applying external force to a switch of a gas discharge device formed on one surface of the battery case, thereby linearly moving a gasket of the gas discharge device and opening a gas discharge hole, such that a first gas generated in the battery case is discharged to an outside of the battery case during the performing of the pre-formation process.