Disclosed herein is a prismatic battery cell wherein a cap plate is mounted at an open top of a prismatic cell case in a state in which an electrode assembly configured to have a structure in which a separator is disposed between a cathode and an anode is mounted in the prismatic cell case, the cap plate is provided with an anode terminal or a cathode terminal as a protruding terminal, and the prismatic cell case is configured to have a structure in which two or more case members divided in a major axis direction, in a minor axis direction, or in the major axis direction and the minor axis direction based on a horizontal sectional shape of the cap plate with respect to the protruding terminal are coupled to each other.