Abstract: An ultrasonic welding apparatus includes: a pressing force measuring anvil including a pressing force measuring sensor; a horn which is installed to vertically move above the pressing force measuring anvil and presses the pressing force measuring anvil when moving downward; a horn down stroke adjustment part that adjusts a down stroke of the horn so that a pressing force of the horn is within a preset pressing force range; and a welding anvil on which welding target members to be welded by the horn are and supportable by the welding anvil and of which a position is changed to a position of the pressing force measuring anvil so that the welding anvil is positioned under the horn after the down stroke of the horn is adjusted to be within the preset pressing force range.

Abstract: An ultrasonic welding device for a secondary battery is provided. The ultrasonic welding device is configured to weld an overlapping surface of an electrode tab and an electrode lead in an electrode assembly. The ultrasonic welding device includes an anvil on which the overlapping surface of the electrode tab and the electrode lead are disposed. A horn is configured to apply ultrasonic waves to the overlapping surface of the electrode tab and the electrode lead while pressing the overlapping surface. The overlapping surface is disposed on the anvil. An electrode tab measuring part is configured to measure a thickness of the electrode tab disposed on the overlapping surface. A pressure adjusting device is configured to adjust a pressure applied to the overlapping surface by the anvil and the horn according to the thickness value of the electrode tab. The thickness value is measured by the electrode tab measuring part.

Abstract: An ultrasonic welding device includes an anvil provided so that an overlapping surface of an electrode tab and an electrode lead, which are provided in an electrode assembly, are configured to be disposed thereon; a horn configured to weld the overlapping surface disposed on the anvil; and an inspection member configured to inspect a horizontal level of an opposing member with respect to the overlapping surface, based on an overlapping surface horizontal value that is a horizontal value of the overlapping surface with respect to a predetermined reference surface and an opposing horizontal value that is a horizontal value of the opposing member, which is one of a welding part of the horn configured to face the overlapping surface and a disposing part of the anvil, on which the overlapping surface is configured to be disposed, with respect to the predetermined reference surface.

Abstract: The present technology relates to a method of inspecting a welding defect. The method includes: manufacturing an electrode assembly sample by welding an electrode lead on an electrode tab formed on an electrode assembly; measuring a tensile strength, a torsional strength and a peeling strength of a welded portion between the electrode tab and the electrode lead for the electrode assembly sample; deriving correlation between whether there is a welding defect and each of the tensile strength, the torsional strength, and the peeling strength; and deriving a reference value for determining whether there is a welding defect for the tensile strength, the torsional strength, and the peeling strength, respectively.

Abstract: The present invention relates to a method for inspecting a welding quality of an electrode tab-electrode lead welded portion of a pouch-type lithium secondary battery, and the method includes: recognizing welding traces of the welded portion by a vision inspection device; measuring a size of each of the recognized welding traces; and determining whether the welded portion has been weakly welded, excessively welded or normally welded by comparing the measured size with a reference value.