NOVELTY - The battery cooling device (1) has a side portion (2) formed by the accumulated bent edges (17) of boards of battery packs (10) stacked over each other. A battery module (11) of battery pack is mounted on the board and a heat pipe (14) is clamped between the pair of boards. The bent edges of the boards are provided in the state of opposing each other. A step portion (20) is provided in each bent edge.    USE - Battery cooling device for electric propulsion vehicle.    ADVANTAGE - The assembling operation is performed simply and easily by stacking battery packs. The number of components is reduced by forming the side of battery cooling device by the bent edges of boards of stacked battery packs. The manufacturing cost is reduced by performing assembling operation easily and reducing the number of components. The mechanical strength is excellent and heat pipe and battery module are protected reliably since heat pipe is clamped by a pair of boards and battery module and board are arranged in turns. The thickness of board is reduced and size and weight reduction are possible by ensuring excellent mechanical strength. The freezing destruction of heat pipe is prevented by protecting the cooling unit of heat-pipe front end by the accumulated board. The application of load to the battery module and heat pipe is prevented even during the stacking of battery packs. The output of battery module is stabilized and a uniform thermal radiation and excellent thermal radiation efficiency are possible. The positioning at the time of stacking battery packs is performed easily and the position shift of the accumulated battery packs is prevented effectively. The weight reduction and improvement of thermal radiation efficiency are possible by mounting battery module in the state of contacting the heat pipe. The number of heat pipes is reduced for reducing the number of components and improving productive efficiency. The temperature control of battery module and the stabilization of the output of electric propulsion vehicle are performed easily.    DESCRIPTION OF DRAWING(S) - The drawing shows a perspective view of the battery cooling device in the state of removing a cover.    Battery cooling device (1)    Side portion (2)    Battery pack (10)    Battery module (11)    Heat pipe (14)    Bent edge (17)    Step portion (20)