ULTRASONIC WELDING DEVICE AND METHOD FOR MANUFACTURING SECONDARY BATTERY USING ULTRASONIC WELDING DEVICE

An ultrasonic welding device according to an embodiment of the present disclosure comprises: an anvil that supports a welding target from below; and a welding horn disposed on the welding target and having a body, at least one pair of heads provided on one end of the body, and a plurality of welding knurls provided on one-side surfaces of the heads, wherein the positions of the heads in primary welding of the welding target and the positions of the heads in secondary welding are different from each other. According to the embodiment of the present disclosure, since a welding area between substrate tabs and a welding area between a substrate tab and a lead tab do not overlap, damage such as breakage or perforation of a welding portion can be prevented. Accordingly, the adhesion between the substrate tabs, and the cutting uniformity of substrate tabs can be improved. In addition, strip terminals can be welded on the uniform surfaces of the substrate tabs, thereby improving welding quality.