Disclosed herein is a prismatic battery cell including an electrode assembly including a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode, the electrode assembly having a positive electrode terminal and a negative electrode terminal protruding from at least one side of the positive electrode and the negative electrode, two or more case members coupled to each other so as to have a shape corresponding to the external shape of the electrode assembly such that the case members surround the electrode assembly, the case members having a predetermined opening, through which one surface of the electrode assembly, at least, corresponding to protruding portions of the positive electrode terminal and the negative electrode terminal is exposed, and a cap plate coupled to the opening of the case members in a sealed state.