Battery and method for manufacturing same

A method for manufacturing a battery comprising:

• preparing a case comprising a bottom portion, a sidewall portion connected to the bottom portion and having a seating portion at one end thereof, and an upper opening opposite to the bottom portion;
• preparing an electrode assembly;
• inserting the electrode assembly into the case;
• and
• coupling a cap assembly to the seating portion of the case,
• wherein the cap assembly comprises at least one first engagement portion for coupling with the case,
• wherein the case comprises at least one second engagement portion respectively corresponding to the at least one first engagement portion, the seating portion comprising the at least one second engagement portion, and
• wherein the at least one first engagement portion and the at least one second engagement portion are coupled to each other to restrict movement of the cap assembly in an upward direction.