NOVELTY - The power supply device has a bind bar (11) that is formed as a side surface of a battery laminated segment (50). A latching bending piece (14) is bent in an upper end so that an upper surface of a battery laminated segment and a lower surface of the bind bar are latched. A fixing unit (30) bends on the opposite side to a bending direction of the latching bending piece, when protruding from the side-surface side of the battery laminated segment. A fixed piece (31) that fixes a bottom face on a mounting plate (6) is provided.    USE - Power supply device used in vehicle (claimed) such as plug-in type hybrid electric vehicle, hybrid type electric vehicle and electric vehicle.    ADVANTAGE - The whole battery laminated segment is fixable to a mounting plate. The separator is latched in the intermediate portion of a battery laminated segment by the latching bending piece, so as to prevent that the separator floats up touch with a mounting plate by a vibration or external force, and can maintain stably. The connection to a mounting plate can be performed with a reliable thing even when fixation of the battery laminated segment in a middle portion becomes firm and the full length of a battery laminated segment becomes long by arranging a several fixed piece in multiple along the length direction of bind bar. The fixed pieces can open the screw hole for fixing to the mounting plate, so that each fixed piece is reliably and easily fixable with a mounting plate by screwing. Thus it becomes possible to prevent that a battery laminated segment floats up touch with a mounting plate by a vibration or external force, and can maintain stably. Since the segment which protrudes from the side surface of a battery laminated segment becomes unnecessary especially according to this structure, it can fix and slim the external shape of a battery laminated segment, and the advantage which can contribute to size reduction of an apparatus is also acquired. The separator can also provide the insertion protrusion portion which covers the upper surface of this square battery cell while pinchingly supporting the square battery cell from both surfaces with a pair of separator, so that a separator prevents floating of a square battery cell. Since a separator is pressed by the latching bending piece of bind bar at the mounting plate side, it can fix a square battery cell stably on a mounting plate as a result. Since battery laminated segment up-and-down both surfaces can be maintained with a separator, a square battery cell is maintained reliably and it can respond to a vibration. The connection structure of a battery laminated segment, a separator, and bind bar is made with a still firmer structure. A battery laminated segment can be cooled from the bottom face side, and the heat bonding state with a cooling plate can be stably maintained especially in the intermediate portion of a battery laminated segment, so that the advantage which can cool a battery laminated body efficiently uniformly not only in an end surface but in the whole is acquired.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for vehicle.    DESCRIPTION OF DRAWING(S) - The drawing shows the perspective view illustrating the state where battery laminated segment is mounted on a mounting plate.    Mounting plate (6)    Bind bar (11)    Latching bending piece (14)    Fixing unit (30)    Fixing piece (31)    Battery laminated segment (50)