A rechargeable battery includes an electrode assembly, a case housing the electrode assembly, an electrode terminal electrically connected to the electrode assembly and a cap plate sealing the case, the cap plate having an electrolyte injection opening. The electrolyte injection opening has a first opening having a first diameter and a second opening having a second diameter both defined by an inner wall of the cap plate, the second diameter being smaller than the first diameter, and a first guide portion between the first opening and the second opening. A sealing cap seals the electrolyte injection opening and includes a sealing member engaging the inner wall of the first opening and a fixing member coupled to the sealing member and engaging the inner wall of the second opening, wherein a portion of the fixing member is spaced from the inner wall of the second opening.