NOVELTY - The battery compartment comprises an outer casing defining a chamber for receiving the battery and including a support (4) and a cover (5) positioned one above the other and having coupling areas, an inner partition defining a compartment in the chamber in which a battery block is arranged with an insulating housing for receiving an electrical battery unit, a unit for attaching the coupling areas to one another, and a stiffening unit, which connect the holder and the cover together. The stiffening unit comprises local deformations arranged in some of the coupling zones.    USE - The battery compartment is useful for a motor vehicle with electric or hybrid propulsion.    ADVANTAGE - The battery compartment exhibits high stiffness and strength and simple and compact design thus allowing its easy interchangeability in the vehicles, and provides safe operation of the vehicles at the electrical point of view without causing any damage.    DETAILED DESCRIPTION - The battery compartment comprises an outer casing defining a chamber for receiving the battery and including a support (4) and a cover (5) positioned one above the other and having coupling areas, an inner partition defining a compartment in the chamber in which a battery block is arranged with an insulating housing for receiving an electrical battery unit, a unit for attaching the coupling areas to one another, and a stiffening unit, which connect the holder and the cover together. The stiffening unit comprises local deformations arranged in some of the coupling zones and engaged respectively to each other. The local deformations comprise embossments engaged respectively into each other. A unit is arranged for further fixing the local deformations. The stiffening unit comprises a beam extending into the receiving chamber, where the beam and the support and the beam and cover are fixed and coupled between each other. A sealing unit is positioned between the coupling zones. The attachment unit comprises a set of sleeves, and screws arranged in the sleeve set. The inner partition and the battery block are arranged inside the outer casing so as to define an internal space transmitting from one compartment to another. The partition comprises a unit for plating the housings of battery block in the compartments. A secondary compartment is disposed in an electrical and/or electronic device connected to the battery, and comprises an external electrical connection. The support comprises a tank with a bottom (6) and a side wall equipped with a peripheral edge folded towards inner side of the compartment and forming a peripheral pairing zone above the tank bottom. The partition extends between the support and the cover. The external envelope is equipped with an outer layer for protection and insulation against fire in part of its surface. A hollow outer housing is arranged for receiving a removable member of a cutoff power switch connected to the battery.    DESCRIPTION OF DRAWING(S) - The diagram shows an exploded perspective view of the battery compartment.    Support (4)    Movable cover (5)    Rectangular flat bottom (6)    Outer side framework (7)    Opposite longitudinal walls (8, 9)    Opposite transverse walls. (10, 11)