NOVELTY - An assembled battery (100) has unit cells (20) each includes an electrode body (80A-80D) having a positive electrode and a negative electrode, and a cell container (50) that houses the electrode body. One or more gap-filling sheets (10a,10b) that fill in a gap between the electrode body and the two side walls (52,54) are inserted in the unit cell container of at least one of the unit cells. One or more gap-filling sheets are disposed so that a distance between the channel-side side wall and electrode body is shorter than a distance between the non-channel-side side wall and electrode body.    USE - Assembled battery for vehicle (claimed) e.g. motor vehicle equipped with electric motor such as hybrid motor vehicle, electric motor vehicle, or fuel-cell motor vehicle.    ADVANTAGE - Prevents deformation of the external shape of one or more of the unit cells by the load that acts in the arrangement direction at the time of constraint since gap that occurs due to non-uniform shapes of electrode bodies housed within the containers is filled in by one or more gap-filling members, thus obtains uniformity of shapes of the unit cells, particularly the thickness of unit cells in the arrangement direction. Ensures rapid dissipation of heat produced within the container in a direction passing through the channel-side side wall since one or more gap-filling members in each container are disposed so that distance between channel-side side wall and electrode body is shorter than the distance between the non-channel-side side wall and electrode body, thus heat-dissipation characteristic of each of the unit cells can be heightened, and cooling efficiency of the assembled battery can be improved, therefore enables size reduction of the cooling fan so that cost of assembled battery is reduced. Degrees of aging degradation and the like of the unit cells can be made equal since distance between the electrode body and channel-side side wall that most contributes to the heat dissipation from the interior of unit cell container i.e. the side wall that directly faces the channel is constant among the unit cells so that heat-dissipation characteristic can be made uniform among the unit cells, thus increased service life of the assembled battery is obtained. Improves reliability of the vehicle equipped with the assembled battery since heat-dissipation characteristic of each of the unit cells that constitute the assembled battery heightens, cooling efficiency of the assembled battery improves, and the service life of the assembled battery will increase.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic sectional view of the state in the containers of unit cells and peripheral structures around the unit cells in a constrained state.    Gap-filling sheets (10a,10b)    Unit cells (20)    Container (50)    Side walls (52,54)    Electrode body (80A-80D)    Assembled battery (100)