Disclosed is a battery cell, which includes a battery case having an accommodation portion in which an electrode assembly is mounted, and a sealing portion formed by sealing an outer periphery thereof; and a gas discharge unit inserted into the sealing portion, wherein the gas discharge unit protrudes from the inside of the battery case toward the outside of the battery case, the gas discharge unit includes a non-adhesive layer and an adhesive layer located on the non-adhesive layer, and the non-adhesive layer and the adhesive layer are bent to be opened toward the inside of the battery case.