Patent ID: 8343647

Claim:
A battery pack comprising a plurality of unit cells electrically connected with each other, wherein the battery pack is constructed in a structure in which a heat transfer medium flows through gaps defined between the unit cells for controlling the overall temperature of the battery pack to be within a predetermined temperature range for the optimum operation of the battery pack; each unit cell is provided at the outer surface thereof, at which the heat transfer medium is brought into contact with each unit cell, with a phase transformation layer for minimizing individual temperature difference between the unit cells; wherein the battery pack is constructed in a structure in which the unit cells are stacked one on another while the unit cells are spaced a predetermined distance from each other to form a plurality of battery groups, and the battery groups are arranged in lateral direction, and the outer surfaces of the battery groups are surrounded by a pack case; wherein the unit cells are mounted in a cartridge while the unit cells are arranged in the lateral direction, and the cartridges are stacked one on another to construct the battery pack; wherein the cartridge comprises a pair of frame members, which can be coupled with each other, and the unit cells are located in cell partition walls of the frame members while the frame members are separated from each other, and are then securely fixed at the cell partition walls of the frame members after the frame members are coupled with each other; and the unit cell has an electrode tap, which is electrically connected to that of the neighboring unit cell via a bus bar located at the upper part of the cartridge.