NOVELTY - The traction battery (1) has a battery box (2) in which all components of the high-performance battery are arranged. The wall surface (3) of the battery box is made of heavy material and is provided with larger wall thickness, such that the additional weight of the traction battery is same as the total weight of lead-acid traction battery with the same external dimensions.    USE - Traction battery such as lithium ion battery for traction battery for battery-electric driven mobile work machine such as counterweight forklift truck used in counterweight forklift truck system (claimed). Can also be used in lithium-polymer battery, lithium-cobalt dioxide battery, lithium-air battery, lithium titanate battery, lithium-iron-phosphate battery, lithium-manganese battery, and tin-sulfur lithium ion battery.    ADVANTAGE - The additional weight of the traction battery is same as the total weight of lead-acid traction battery with the same external dimensions, so that the weight of the battery can be reduced. The energy density of the battery can be improved. Thus, large amount of electrical energy can be stored reliably and the service life of the forklift truck can be improved. The manufacturing cost of the traction battery can be reduced. Uniform weight and load distribution of the battery can be improved. The battery can be lifted easily by using the lifting lugs, and the leakage of liquids from the battery cells can be prevented. The battery box can be protected against mechanical damage. The weight distribution and stability of the industrial truck can be improved. Thus, the battery can provide best performance in terms of energy density over the volume as well as the weight. The exchange operation of the traction battery can be performed easily by switching freely between the high-performance battery and conventional lead-acid traction battery.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the traction battery.    Traction battery (1)    Battery box (2)    Wall surface (3)    Flange (4)    Cover (5)