Switch-off device, high-voltage onboard electrical system, and motor vehicle

1. A switch-off device for a high-voltage onboard system of a motor vehicle, the switch-off device comprising:

a current conductor for providing a load current path between components of the high-voltage onboard system,

a pyrotechnically activatable separating unit for interrupting the load current path in an event of a fault, the pyrotechnically activatable separating unit having a separating element and a pyrotechnic element, wherein the pyrotechnic element is configured, in the event of the fault, to accelerate the separating element in a direction of the current conductor, and wherein the separating element is configured to separate the current conductor, for interruption of the load current path, and

an arc quenching unit for quenching an arc which is generated upon interruption of the load current path, the arc quenching unit having a melting conductor which, under normal circumstances, is not incorporated in the load current path, and having a quenching device for quenching the melting conductor,

wherein the separating element is configured, upon separation of the current conductor, to bend a current conductor piece for transfer of an arc generated on the melting conductor in a direction of the melting conductor, and thereby to incorporate the melting conductor in the load current path in the event of the fault which generates the arc, and

wherein the bent current conductor piece and the melting conductor are arranged in an at least temporarily contact-free manner relative to each other during the transfer of the arc.

2. The switch-off device according to claim 1 , wherein:

the melting conductor is positioned such that a clearance between the bent current conductor piece and the melting conductor is smaller than a clearance between the bent current conductor piece and a remainder of the current conductor.

3. The switch-off device according to claim 1 , wherein:

the melting conductor is positioned such that the bent current conductor piece is arranged with a permanent clearance from the melting conductor, such that the arc is transferrable in a contact-free manner from the bent current conductor piece to the melting conductor.

4. The switch-off device according to claim 1 , wherein:

the separating element is constituted as a separating piston, and

the separating unit comprises a guide cylinder in which the separating piston is arranged and in the event of acceleration is guidable in the direction of the current conductor.

5. The switch-off device according to claim 1 , wherein:

the separating unit comprises a brake block which is configured to arrest the separating element further to the separation of the current conductor, and thus to define a clearance between the bent current conductor piece and the melting conductor.

6. The switch-off device according to claim 5 , wherein:

the braking piston is sprung such that, further to bending of the current conductor piece, a temporary contact can be established between the bent current conductor piece and the melting conductor, for improved arc transfer.

7. The switch-off device according to claim 1 , wherein:

the quenching device is constituted as a quenching sand.

8. The switch-off device according to claim 1 , wherein:

the current conductor incorporates a predetermined break point for the separating element.

9. A high-voltage onboard system for a motor vehicle, the high-voltage onboard system comprising:

at least two components, and

at least one switch-off device for the electrical connection of the components according to claim 1 .

10. A motor vehicle comprising the high-voltage onboard system according to claim 9 .