Abstract: The invention relates in particular to a device for reinforcing a rear axle of a vehicle, which comprises an electric motor and a fuel tank having a concavity able to provide passage for an exhaust pipe. The vehicle comprises a vehicle floor. The reinforcing device comprises a cradle (5) having two arms (50, 51) between which the electric motor can be received. The device further comprises an elongate reinforcing element (6) which extends in a direction perpendicular to the two arms (50, 51) from one (50) of the two arms in the center thereof, the elongate reinforcing element (6) being able to extend above the floor of the vehicle and in the concavity of the fuel tank, the elongate reinforcing element having an element length and a receiving housing which extends over the entire element length to provide passage for the exhaust pipe.