Electrical switching unit with safety device

Abstract

Electrical switching unit (1) for a high-voltage drive system of a hybrid or electric vehicle, comprising a contact device with at least one fixed first connection element (2) and at least one movable second connection element (4), wherein the movable second connection element (4) can be actuated via a first actuator (6) into a closed position in which the first connection element (2) and the second connection element (4) are electrically connected, and into an open position in which the first connection element (2) and the second connection element (4) are not electrically connected, and comprising a safety device with at least one electrically insulating separating element (7) and at least one second actuator (8), wherein the separating element (7) is designed to be displaceable via the second actuator (8) in such a way that, when required, it can be moved independently of the position of the movable contact bridge (5),can be moved into the area between the first connecting element (2) and the second connecting element (3).,

Description

Field of the invention

[0001] The present invention relates to an electrical switching unit for a high-voltage drive system of a hybrid or electric vehicle, comprising a contact device with at least one fixed first connection element and at least one movable second connection element, wherein the movable second connection element can be actuated via a first actuator into a closed position in which the first connection element and the second connection element are electrically connected, and into an open position in which the first connection element and the second connection element are not electrically connected, and comprising a securing device. State of the art

[0002] High-voltage architectures of hybrid and electric vehicle energy storage systems often use fuses and / or pyrotechnic fuses to protect against electrical short circuits and / or overloads. In both cases, separate components must be integrated into the high-voltage path.

[0003] The use of fuses not only requires additional space and additional interfaces, but also leads to undesirable aging. Even normal loads can damage fuses and thus lead to undesirable triggering behavior over their lifetime.

[0004] Compared to thermal fuses, pyrotechnic fuses do not exhibit any aging effects. Nevertheless, similar to a melting fuse, their use requires additional space and interfaces. Furthermore, the force of the pyrotechnic fuse must be sufficiently high to be able to break a copper or aluminum busbar designed for currents of up to 600 amperes.

[0005] Document DE 10 2017 205 833 A1, for example, describes an electrical switching unit, namely a contactor device, comprising a contact device and a safety device. The contact device has stationary first connection elements, namely two second contact elements, a movable second connection element, namely a first contact element coupled to an armature, and a first actuator, namely a drive device for moving the armature. The movable first contact element can be actuated by the first actuator into a closed position, in which the first contact element mechanically contacts the two second contact elements and the second contact elements are thus electrically connected via the first contact element, and into an open position, in which there is no electrical connection between the first contact element and the second contact elements.The safety device comprises an electrically insulating separating element, namely at least one movable insulating element, and a second actuator for moving the insulating element. The safety device is designed to break an electrical contact existing between the first contact element and the second contact elements in at least one predetermined fault situation.

[0006] For example, document US 2015 / 0 213 983 A1 describes an electrical contactor with a double-leaf switch, with iron plates attached to the leaves to increase the current carrying capacity and reduce the resistance of the switch. The contacts of the switches are arranged in pairs, with at least one contact pair arranged to close before another contact pair.

[0007] The document DE 10 2018 131 327 A1 describes, for example, a safety device, in particular for a vehicle, for connecting or disconnecting sections of an electrical conductor with an electromagnetic switching element, wherein the sections of the electrical conductor are electrically conductively connected to one another in a rest state of the safety device and can be separated from one another in an activated state when a separation signal is applied in order to interrupt a current flow through the conductor, and wherein the safety device further comprises a pyrotechnic actuator which is designed to assist in separating the sections of the electrical conductor when the separation signal is applied. Summary of the invention

[0008] It is an object of the invention to provide an improved electrical switching unit for a high-voltage drive system of a hybrid or electric vehicle, which is characterized in particular by a reduced installation space requirement.

[0009] This need can be met by the subject matter of the present invention according to independent claim 1. Advantageous embodiments of the present invention are described in the dependent claims.

[0010] An electrical switching unit according to the invention for a high-voltage drive system of a hybrid or electric vehicle comprises a contact device and a safety device.

[0011] According to the invention, the contact device has at least one fixed first connection element and at least one movable second connection element.

[0012] According to the present invention, the movable second connection element can be actuated via a first actuator into a closed position in which the first connection element and the second connection element are electrically connected, and into an open position in which the first connection element and the second connection element are not electrically connected.

[0013] According to the invention, the safety device has at least one electrically insulating separating element and at least one second actuator, wherein the separating element is designed to be displaceable via the second actuator in such a way that it can be moved into the area between the first connecting element and the second connecting element if necessary, usually in the event of an electrical fault when the movable second connecting element is in the closed position.

[0014] In a particularly preferred embodiment of the present invention, the separating element is wedge-shaped, tapering toward a connecting element. However, the separating element can also be designed in any other desired shape.

[0015] The second actuator can be designed as a pyromechanical actuator, via which the isolating element can be moved from a basic position into a isolating position, namely a position between the first connection element and the second connection element, by means of an explosive movement. In contrast to conventional pyrotechnic fuses, an isolating element is not used to break a busbar, but rather to prevent contact between the movable second connection element and the stationary, i.e. fixed, first connection element. The force required for this is less than the force required to sever a solid busbar. By using a pyromechanical actuator, the necessary shutdown speeds can be achieved, for example in the event of a low-resistance short circuit.However, any other actuator that can provide the necessary triggering times is also conceivable.

[0016] A pyromechanical actuator is usually an irreversibly triggered actuation mechanism - once the propellant charge is used up, it must be replaced.

[0017] However, the separating element can also be designed to be reversibly actuated. The resulting solution can be used, for example, to guide an arc generated during a closing and / or opening sequence, as well as for automatic or manual locking during servicing. Such a reversible separating function can also be used in the event of a possible return spring break (of the movable connecting element) to implement safe emergency operation. Brief description of the drawings

[0018] The invention is described below by way of example with reference to the drawings. Fig. 1 shows a side view of an electrical switching unit with a movable second connection element in the closed position and a separating element in the basic position. Fig. 2 shows a side view of an electrical switching unit with a movable second connection element in the open position and a separating element in the separating position Fig. 3 shows a cross section through an electrical switching unit according to Fig. 1. Detailed description of the invention

[0019] An embodiment of an electrical switching unit 1 according to the invention for a high-voltage drive system of a hybrid or electric vehicle is described below with reference to the Fig. 1, the Fig. 2 and the Fig. 3 described in more detail.

[0020] The electrical switching unit 1 comprises a housing 10, a contact device, and a safety device. The contact device and the safety device are essentially arranged in the housing 10.

[0021] The contact device has two fixed first connection elements 2 and two movable second connection elements 4.

[0022] The two second connection elements 4 are arranged on a movable contact bridge 5. In the present embodiment, the two first connection elements 2 are each designed as a fixed busbar.

[0023] The movable contact bridge 5 and thus the two second connection elements 4 are moved into a closed position ( Fig. 1, Fig. 3), in which the first connection element 2 and the second connection element 4 are electrically connected, and in an open position ( Fig. 2), in which the first connection element 2 and the second connection element 4 are not electrically connected, can be actuated. The movable contact bridge 5 can be guided via guide pins 11 fixed in the housing 10.

[0024] The safety device comprises an electrically insulating isolating element 7 and a second actuator 8. The isolating element 7 can be displaced via the second actuator 8, starting from a basic position into a disengaged position, and when using a reversibly triggerable second actuator 8, also vice versa, into an area between the first connection element and the second connection element, regardless of the position of the movable contact bridge 5. Such a displacement of the isolating element 7 is triggered in particular in the event of an electrical fault, such as an electrical short circuit or an electrical overload, and causes an interruption of the current flow via the first connection element 2 and the second connection element 4 ( Fig. 2).

[0025] The separating element 7 is wedge-shaped—its two side surfaces converge at an acute angle. This acute angle forms in the direction of the connecting elements 2, 4.

[0026] In the present embodiment, the second actuator 8 is designed as a pyromechanical actuator, via which the separating element 7 can be transferred by an explosive movement starting from a basic position into a separating position, namely a position between the first connecting element and the second connecting element.

[0027] A stop plate 12 is provided to stop the explosive movement of the separating element 7. This is arranged on the movable contact bridge 5 and prevents further (unintentional) displacement of the separating element 7. List of reference symbols 1 Electrical switching unit 2 First connecting element 4 Second connection element 5 Movable contact bridge 6 First actuator 7 Separating element 8 Second actuator 9 Elastic element 10 housings 11 Guide pin 12 stop plate

Claims

[1] Electrical switching unit (1) for a high-voltage drive system of a hybrid or electric vehicle, comprising a contact device with at least one fixed first connection element (2) and at least one movable second connection element (4), wherein the movable second connection element (4) is arranged on a movable contact bridge (5) and wherein the movable contact bridge (5) and thus the movable second connection element (4) can be actuated via a first actuator (6) into a closed position in which the first connection element (2) and the second connection element (4) are electrically connected, and into an open position in which the first connection element (2) and the second connection element (4) are not electrically connected, and comprising a safety device with at least one electrically insulating separating element (7) and at least one second actuator (8), characterized bythat the separating element (7) is designed to be displaceable via the second actuator (8) in such a way that, if necessary, it can be moved into the area between the first connecting element (2) and the second connecting element (4), regardless of the position of the movable contact bridge (5). [2] Electrical switching unit (1) according to claim 1, characterized by that the separating element (7) is wedge-shaped, tapering in the direction of a pair of connecting elements (2, 4). [3] Electrical switching unit (1) according to claim 1 or 2, characterized by that the second actuator (8) is designed as a pyromechanical actuator via which the separating element (7) can be transferred from a basic position into a separating position by an explosive movement. [4] Electrical switching unit (1) according to claim 1 or 2, characterized by that the separating element (7) is designed to be reversibly actuated.

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