A secondary battery module includes a unit battery pack having a plurality of unit batteries arranged at predetermined intervals, and a housing having the unit battery pack disposed in the housing. A heat transfer medium for controlling temperature of the plurality of unit batteries circulates in the housing. A first dispersion plate is fixedly disposed in the housing so as to be adjacent to the unit battery pack, and distributes the heat transfer medium between the plurality of unit batteries. A second dispersion plate is slidably disposed on the first dispersion plate, and distributes the heat transfer medium between the plurality of unit batteries.