Disclosed herein are a secondary battery, which is formed in the shape of a plate and has an
electrode assembly mounted in a battery case made of a laminated sheet including a
metal layer and a resin layer, wherein the secondary battery is constructed in a structure in which independent
coupling type frame members are mounted to the outside part of a sheathing member serving as the battery case, and a medium- or large-sized battery module including the same as a unit
cell. Consequently, the secondary battery has a high
mechanical strength and a large sealing force. Furthermore, the
electrical connection is accomplished without bending the
electrode leads. Also, the battery module, which is constructed with the secondary battery as a unit
cell, can be manufactured with a compact structure and a relatively light weight. Furthermore, the
assembly process of the battery module is greatly simplified. The
structural stability of the battery module according to the present invention is very high, and therefore, the battery module can be preferably used as a power source for electric vehicles,
hybrid electric vehicles,
electric motor cycles, and electric bicycles.