A rechargeable battery having a compact size and improved strength comprises a case, a battery cell, a circuit board and a covering member. The case has an internal space and an open end. The battery cell is made of a pliable material and is installed within the case, wherein a surface of the battery cell is electrically connected to the circuit board at the open end of the case. The covering member hermetically seals the open end of the case. Accordingly, the battery has a compact size, improved strength and may be manufactured easily.