Rechargeable battery including a rotation restricting portion

A rechargeable battery, comprising:

• an electrode assembly in which a separator is arranged between a positive electrode and a negative electrode;
• an electrolyte disposed in the electrode assembly;
• a can accommodating the electrode assembly and the electrolyte;
• an upper insulation plate disposed on an upper portion of the electrode assembly, the upper insulation plate being in contact with the upper portion of the electrode assembly;
• a cap assembly physically coupled to an upper portion of the can;
• a gasket formed separately from the upper insulation plate and the gasket comprising a first portion and a second portion protruding from the first portion towards the upper insulation plate, the first portion of the gasket arranged between the cap assembly and the upper portion of the can to form a seal between the cap assembly and the upper portion of the can, a lower surface of the second portion of the gasket being in physical contact with an upper surface of the upper insulation plate;
• and
• a rotation restricting portion disposed to restrict rotation of the upper insulation plate relative to the gasket and formed at least at the lower surface of the second portion of the gasket, the rotation restricting portion comprising a plurality of uneven portions which face the upper insulation plate.