An expansion device for a bulk goods container includes a frame, a plurality of wall panels that are connected to the frame in an articulated manner to pivot outwardly such that a pivoted-out position delimit an interior space of the expansion device, connecting elements that are connected in an articulated manner to the wall panels at two edges of the connecting elements and first expansion elements that are connected in an articulated manner to an upper edge of the wall panels and are configured to pivot between a position resting against the wall panels and a position that extends the wall panels. The position extending the wall panels, flexible membrane elements are tensioned between the first expansion elements.
