NOVELTY - The electrical power supply and/or storage device comprises electrical power supply housings (50) arranged in series, a rack provided with sites for receiving housings in a detachable manner, a site (55) comprising electrical contacts (56, 57) for electrically connecting a housing to terminals of the electrical power supply and/or storage device by a power bus (65), a detection device, a locking/unlocking device provided in the site, and a voltage limiting device for avoiding excessive rise in voltage at a rack switch (60). The site is associated with the rack switch.    USE - The electrical power supply and/or storage device such as a battery comprising detachable housings including cells (claimed) is useful for a motor vehicle.    ADVANTAGE - The electrical power supply and/or storage device exhibits high efficiency, improved performance and lifespan, and excellent charge-discharge characteristics.    DETAILED DESCRIPTION - The electrical power supply and/or storage device comprises electrical power supply housings (50) arranged in series, a rack provided with sites for receiving housings in a detachable manner, a site (55) comprising electrical contacts (56, 57) for electrically connecting a housing to terminals of the electrical power supply and/or storage device by a power bus (65), a detection device, a locking/unlocking device provided in the site, and a voltage limiting device for avoiding excessive rise in voltage at a rack switch (60). The site is associated with the rack switch so that an electrical power supply is maintained, in the absence of a certain housing in a certain site, by the housing arranged in another site of the rack. A housing of the detection device is associated with a mechanical or electronic actuator of the rack switch arranged on the power bus for its automatic closing during the removal of the housing and for its automatic opening during the insertion of the housing. The detection device is associated with the locking/unlocking device. The rack switch is a mechanical switch, a relay or an electronic switch such as a transistor. The actuator actuates the rack switch in a duration of less than or equal to 10 ms. The rack comprises a communication bus, and a connector for connecting the housing, which is disposed in the site, with the communication bus. The housing comprises an internal switch adapted to configure with an output zero voltage line. The detection device automatically generates an operation command of the internal switch for configuring the housing with the output zero voltage line during its removal from the site and for reconfiguring the housing in the output zero voltage line after its insertion in the site. The sites are configured for electrically connecting the housings in parallel. An INDEPENDENT CLAIM is included for a process for controlling an electrical power supply and/or storage device.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic view of an electrical power supply and/or storage device.    Electrical power supply housings (50)    Site (55)    Electrical contacts (56, 57)    Rack switch (60)    Power bus. (65)