Button cell

A button cell comprising:

• an electrode assembly comprising a first electrode, a second electrode, and a separator between the first electrode and the second electrode;
• a case comprising an inner space accommodating the electrode assembly, and an opening;
• a cap plate coupled to the case at the opening and comprising a terminal hole exposing the inner space;
• an electrode terminal electrically connected to the electrode assembly through the terminal hole and overlapping the cap plate;
• electrode tabs respectively connected to the first electrode and the second electrode;
• and
• an electrolyte solution in the inner space,
• wherein at least one electrode tab of the electrode tabs comprises an inclined portion that is inclined at a first angle with respect to a surface of the electrode assembly facing the at least one electrode tab,
• wherein the electrode terminal comprises:
• a flange portion covering the terminal hole and overlapping the cap plate;
• and
• a protrusion protruding from the flange portion toward the terminal hole, and
• wherein an outer surface of the protrusion has a curved surface and an inclined surface, and a distance from the curved surface to an end portion of the cap plate exposed by the terminal hole is shorter than a distance from the inclined surface to the end portion of the cap plate exposed by the terminal hole, and
• the distance from the inclined surface to the end portion of the cap plate exposed by the terminal hole becomes longer moving closer to an end portion of the inclined portion.