A lead tap that includes an insulation cover including a boss unit, which protrudes from a surface of the insulation cover and includes an electrical insulating material; and a thermal cut-off device assembly including: a thermal cut-off device; a first lead and a second lead that are coupled to the thermal cut-off device; and a hole through which a portion of the boss unit of the insulation cover protrudes. Here, the boss unit of the insulation cover includes an edge unit that is larger than an opening of the hole of the thermal cut-off device assembly to secure the insulation cover to the thermal cut-off device assembly.