SECONDARY BATTERY

The present invention provides a secondary battery provided with a pouch, in which a sealing potion formed on an edge thereof is sealed when an electrode assembly and an electrolyte are enclosed, the secondary battery comprising: a valve which is mounted on a sealing portion so that one end thereof is disposed inside the pouch, and the other end thereof is disposed outside the pouch and discharges a gas generated inside the pouch to the outside, wherein the valve comprises an inner tube filled with an adhesive and made of a material that is deformed when swelling occurs, and when the swelling occurs to increase in pressure inside the pouch, a gap is generated in a portion that is filled with the adhesive, and the gas within the pouch is discharged to the outside though the gap.In the present invention having the above configuration, the adhesive may be filled in the inner tube to prevent the electrolyte from leaking and prevent external moisture from being permeated, but only when the pressure inside the pouch increases, the gap may be generated to discharge the gas, thereby efficiently preventing the swelling from occurring.