SECONDARY BATTERY MODULE

There is provided a secondary battery module in which heat can be uniformly radiated with high efficiency and the temperature of a cell can be uniformly maintained. An NaS battery module includes a container, a plurality of cells for an NaS battery, sand, and a mica plate. The container includes a main body provided with side walls and a lower wall, and a cover provided with an upper wall. The side walls partition the inside and outside of the container in a direction in which the arrangement plane of the cells extends. The upper wall and the lower wall partition the inside and outside of the container in a direction perpendicular to the direction in which the arrangement plane of the cells extends. The lower wall and the side walls are high heat insulating walls whereas the upper wall is a solid low heat insulating wall having a heat insulating property lower than that of the high heat insulating wall. The cells, the sand, and the mica plate are housed inside of the container. A variable louver is disposed outside of the upper wall so as to cover the outer surface of the upper wall.