A secondary battery and a manufacturing method thereof are disclosed. In one embodiment, the secondary battery includes 1) an electrode assembly comprising an outer surface, 2) an electrolyte, 3) a sealing tape attached to and surrounding at least part of the outer surface of the electrode assembly, wherein the sealing tape comprises i) an adhesive layer contacting the outer surface of the electrode assembly and ii) a base layer formed on the adhesive layer, and wherein the base layer is formed of a material which has directionality and 4) a can accommodating the electrode assembly and sealing tape, wherein the base layer is configured to at least partially lose directionality upon contacting the electrolyte so that at least a portion of the base layer contacts an inner surface of the can.