Device and method for inspecting welded state for cylindrical secondary battery

A method for inspecting a welded state for a cylindrical secondary battery, the method comprising:

• preparing an electrode assembly comprising a plurality of welded portions coupling a non-coating portion of an electrode to an electrode tab;
• measuring a resistance value of each of the plurality of welded portions by using a resistance measurer having a plurality of resistance measurement probes;
• and
• comparing the resistance values of the plurality of welded portions, which are measured through the resistance measurer, with a critical resistance value,
• wherein, when the resistance value of at least one welded portion among the plurality of welded portions exceeds the critical resistance value, the at least one welded portion is determined to have a weak welding,
• wherein, in the measuring the resistance value of each of the plurality of welded portions, the plurality of resistance measurement probes are in contact with a non-welding surface disposed between the plurality of welded portions, and non-welding surfaces outside outermost welded portions of the plurality of welded portions to measure the resistance values of the plurality of welded portions, respectively, and
• wherein the resistance measurer comprises:
• a seating member configured to support a welding area provided with the plurality of welded portions at which the non-coating portion of the electrode and the electrode tab are coupled to each other;
• a fixing member disposed at one side of a top surface of the seating member, the fixing member having a vertical surface and a fixing piece extending from an upper end of the vertical surface;
• a coupling member disposed on the vertical surface of the fixing member, the coupling member being coupled to the plurality of resistance measurement probes, the coupling member being configured to arrange the plurality of resistance measurement probes to be in simultaneous contact with the non-welding surface disposed between the plurality of welded portions and the non-welding surfaces outside the outermost welded portions;
• and
• an elevation member fixed to the fixing piece, the elevation member being configured to cause the coupling member to descend in a direction of the plurality of welded portions so that the plurality of resistance measurement probes are in simultaneous contact with the non-welding surfaces.