Connection/disconnection device between a rechargeable battery and an electrical connection bar, known as a busbar (B1, B2), comprising: - an output terminal (4, 5) of the rechargeable battery, comprising: • an electrically conductive part, • a magnetic lock comprising a permanent magnet, the permanent magnet being provided with an electrically insulating mandrel around which is wound an electrically conductive wire forming a coil that is intended to generate a magnetic field parallel to the magnetic field of the permanent magnet; - a first ferromagnetic part integral with the busbar, forming a closure plate of a magnetic circuit with the magnetic lock, the closed magnetic circuit ensuring a mechanical and electrical connection between the output terminal and the busbar, - an electronic control system designed to charge and monitor the states of the rechargeable battery; the device being configured such that: i/ when the coil is not initially supplied with electrical power, the magnetic attraction force of the permanent magnet on the closure plate, in the configuration of the closed magnetic circuit, maintains the mechanical connection between the output terminal and the busbar with the electrical contact between them; ii/ when the coil is supplied with electrical power through the control of the BMS in a given direction, it produces a magnetic field opposite to that of the permanent magnet to the point of cancelling out the attraction force of the permanent magnet, which brings about mechanical disconnection between the output terminal and the busbar and elimination of the electrical contact between them. - an output terminal (4, 5) of the rechargeable battery, comprising: • an electrically conductive part, • a magnetic lock comprising a permanent magnet, the permanent magnet being provided with an electrically insulating mandrel around which is wound an electrically conductive wire forming a coil that is intended to generate a magnetic field parallel to the magnetic field of the permanent magnet; • an electrically conductive part, • a magnetic lock comprising a permanent magnet, the permanent magnet being provided with an electrically insulating mandrel around which is wound an electrically conductive wire forming a coil that is intended to generate a magnetic field parallel to the magnetic field of the permanent magnet; - a first ferromagnetic part integral with the busbar, forming a closure plate of a magnetic circuit with the magnetic lock, the closed magnetic circuit ensuring a mechanical and electrical connection between the output terminal and the busbar, - an electronic control system designed to charge and monitor the states of the rechargeable battery; i/ when the coil is not initially supplied with electrical power, the magnetic attraction force of the permanent magnet on the closure plate, in the configuration of the closed magnetic circuit, maintains the mechanical connection between the output terminal and the busbar with the electrical contact between them; ii/ when the coil is supplied with electrical power through the control of the BMS in a given direction, it produces a magnetic field opposite to that of the permanent magnet to the point of cancelling out the attraction force of the permanent magnet, which brings about mechanical disconnection between the output terminal and the busbar and elimination of the electrical contact between them.