SECONDARY BATTERY

The present invention provides a secondary battery in which an electrode assembly and an electrolyte are inserted and injected into a pouch, and an edge of the pouch is sealed to form a sealing portion, the secondary battery comprising: a valve fixed to the sealing portion so that one end thereof faces the inside of the pouch, and the other end thereof faces the outside of the pouch, wherein the valve comprises: a body forming a passage having opened one end facing the inside of the pouch and provided with a chamber connected to the passage, wherein a discharge hole communicating with the outside is formed in the chamber; a gate seated on a hook protrusion forming a boundary between the passage and the chamber to open or close the passage; and a spring mounted to apply elastic force in a direction in which the gate is closed, wherein a gas is generated inside the pouch, and a pressure of the gas overcomes the elastic force of the spring, the gate is opened to discharge the gas through the discharge hole.In the present invention having the configuration as described above, when the gas is generated inside the pouch, and the pressure of the gas overcomes the elastic force of the spring, the gate may be opened to discharge to the discharge hole, thereby efficiently preventing the swelling from occurring and preventing moisture and the foreign substances from being introduced from the outside of the valve.