The absorption device includes a hydrophilic powder and a casing which is permeable to a liquid, the casing being composed of an upper layer which is superimposed on a lower layer, the lower and upper layers being connected to each other by strong connections which delimit a confinement zone for the hydrophilic powder in the casing. Advantageously, the lower and upper layers are connected to each other by first weak connections. The first weak connections delimit a plurality of adjacent cells in the confinement zone, each cell enclosing a quantity of hydrophilic powder sufficient to bring about the breakage of the first weak connections which delimit the cell when the hydrophilic powder absorbs a liquid.