Disconnecting devices, high-voltage onboard power supplies and vehicles

Abstract

The invention relates to a disconnection device (1) for a high-voltage onboard power system of a motor vehicle, comprising: an electrical conductor (2) for forming a load current path; a pyrotechnically activatable disconnection unit (3) for interrupting the load current path in the event of a fault, the disconnection unit having a disconnection element (5) for disconnecting the electrical conductor (2) and a pyrotechnical element (4) for accelerating the disconnection element (6) in the direction of the electrical conductor (2); and an arc extinguishing unit (13) for extinguishing an arc, the disconnection unit having a disconnection element (5) for disconnecting the electrical conductor (2) and a pyrotechnical element (4) for accelerating the disconnection element (6) in the direction of the electrical conductor (2). The invention relates to a fusible conductor (14) in a load current path and an extinguishing agent (15) for extinguishing the fusible conductor (14); the separating element (7) is designed to bend the conductor section (11) in the direction of the fusible conductor (14) in order to transfer the arc to the fusible conductor (14) when the conductor (2) is cut, and thereby to connect the fusible conductor (14) into the load current path in the event of a fault causing an arc, the bent conductor section (11) and the fusible conductor (14) being arranged at least temporarily without contact with each other during the arc transfer.

Description

Technical Field

[0001] The invention relates to a disconnect device for a high-voltage onboard power supply system of a motor vehicle, comprising an electrical conductor for forming a load current path between components of the high-voltage onboard power supply system and a pyrotechnically activatable disconnection unit for interrupting the load current path in the event of a fault, the disconnection unit comprising a disconnection element and a pyrotechnical element, wherein the pyrotechnical element is designed to accelerate the disconnection element in the direction of the electrical conductor in the event of a fault, and the disconnection element is designed to disconnect the electrical conductor in order to interrupt the load current path. The invention further relates to a high-voltage onboard power supply system and a motor vehicle. Background Art

[0002] The present invention is concerned with high-voltage onboard power systems of motor vehicles, for example electrically driven motor vehicles. Such high-voltage onboard power systems have a plurality of components, which can be designed, for example, as a traction battery and as at least one high-voltage consumer, in particular an electric drive machine. The components are electrically connected via electrical conductors, for example busbars, for the purpose of load current transmission. In the event of a fault, for example, when an overcurrent or fault current flows through the electrical conductors, the components must be reliably separated from one another.

[0003] For this purpose, it is known from the prior art to provide a disconnecting unit which can interrupt the load current path between the components. The disconnecting unit can be activated, for example, by pyrotechnics. For this purpose, the disconnecting unit has a pyrotechnic unit and a disconnecting element. In the event of an overcurrent, the pyrotechnic unit is ignited, i.e. activated, and accelerates the disconnecting element in the direction of the electrical conductor, which then cuts off the electrical conductor and thus interrupts the load current path. When the electrical conductor is cut off, the electrical conductor is divided into two electrical conductor areas, wherein an undesirable arc can occur between the electrical conductor areas. In the worst case, this undesirable arc can cause the motor vehicle to catch fire. Summary of the invention

[0004] The object of the present invention is to provide a simple solution for how load current paths between components of a high-voltage onboard electrical system can be interrupted safely and reliably.

[0005] This object is achieved according to the invention by a disconnect device, a high-voltage onboard power supply system and a motor vehicle.

[0006] The disconnection device for a high-voltage onboard power system of a motor vehicle according to the present invention has a conductor for forming a load current path between components of the high-voltage onboard power system and a pyrotechnically activatable separation unit for interrupting the load current path in the event of a fault. The separation unit has a separation element and a pyrotechnical element, wherein the pyrotechnical element is designed to accelerate the separation element in the direction of the conductor in the event of a fault, and the separation element is designed to cut off the conductor in order to interrupt the load current path. In addition, the disconnection device has an arc extinguishing unit for extinguishing the arc generated when the load current path is interrupted. The arc extinguishing unit has a fusible conductor that is not normally connected to the load current path and an extinguishing agent for extinguishing the fusible conductor. The separation element is designed to bend a conductor section in the direction of the fusible conductor in order to transfer the generated arc to the fusible conductor when cutting the conductor and thereby connect the fusible conductor to the load current path in the event of a fault that causes an arc, wherein the bent conductor section and the fusible conductor are arranged at least temporarily without contact with each other during the arc transfer.

[0007] The invention further relates to a high-voltage onboard power supply system for a motor vehicle, which has at least two components and at least one disconnection device according to the invention, which is designed to electrically connect the components in normal conditions and to electrically disconnect the components in the event of a fault. The components may be, for example, a traction energy store designed as a high-voltage energy store and an electric drive.

[0008] The disconnection device has an electrical conductor, which is in particular configured as a busbar. The electrical conductor electrically connects the at least two components. Under normal circumstances, that is, when there is no overcurrent flowing through the electrical conductor and / or when a motor vehicle accident occurs, the electrical conductor can conduct a load current in the form of an operating current. In addition, the disconnection device has a separation unit, which is designed to mechanically interrupt the electrical conductor in the event of a fault, that is, when there is an overcurrent flowing through the electrical conductor and / or in the event of an accident, and thereby electrically separate the components from each other. The separation unit can be activated by pyrotechnics and has a separation element and a pyrotechnic element. The separation element can be, for example, a separation piston. The separation piston can, for example, have an inclined guillotine-shaped separation surface, which can cut off the electrical conductor. The pyrotechnic element can, for example, be an igniter. The pyrotechnic element can be connected to a control device of the motor vehicle, such as a battery management system, which is designed to activate the pyrotechnic element. The control device, for example, contains a current monitoring device. The control device can also have a crash interface, which is, for example, connected to an airbag controller for detecting a motor vehicle accident.

[0009] As soon as a fault is detected by the control device, the control device provides an activation signal to the pyrotechnic element. As a result, the pyrotechnic element is ignited and accelerates the separation element in the direction of the electrical conductor. The separation element cuts the electrical conductor and thereby divides the electrical conductor into at least two electrical conductor regions. Here, the electrical conductor is deformed during the cutting so that the separation element bends or bends the electrical conductor section of the first electrical conductor region away from the second electrical conductor region. That is, the bent electrical conductor section forms a switching lever of the switch, which is opened by the separation element and thus interrupts the electrical connection between the two electrical conductor regions and thus the electrical connection between the two components.

[0010] Now, in order to prevent the formation of an undesirable arc, i.e., an interfering arc, between two conductor regions when the conductor is cut off, an arc extinguishing unit is provided. The arc extinguishing unit has a fusible conductor, which is configured to limit the current in such a way that the fusible conductor melts when there is an overcurrent flowing through the fusible conductor. The molten fusible conductor is extinguished by a fire extinguishing agent, such as extinguishing sand. For this purpose, the fusible conductor is, for example, embedded in the extinguishing agent or surrounded by the extinguishing agent. Here, the fusible conductor is not normally incorporated into the load current path. For example, the first end or the first connection of the fusible conductor can be connected to the second conductor region, while the second end or the second connection of the fusible conductor is not connected. In the case of a load current in the form of an overcurrent flowing through the conductor, the fusible conductor is then incorporated into the load current path in such a way that the conductor section of the first conductor region does not transfer the arc to the second conductor region, but transfers the arc to the fusible conductor, so that the overcurrent flows through the fusible conductor for a short time.

[0011] To this end, the conductor segment is bent in the direction of the second connection of the fusible conductor, but at least temporarily does not contact it. That is, the fusible conductor and the bent conductor segment are at least temporarily spaced apart from each other or arranged without contact with each other. That is, the fusible conductor and the bent conductor segment are at least temporarily electrically separated, wherein the arc can bridge or overcome the distance between the fusible conductor and the bent conductor segment and thus integrate the fusible conductor into the load current path. The fusible conductor melts and is extinguished by the extinguishing agent. The fusible conductor is preferably positioned so that the bent conductor segment is permanently spaced apart from the fusible conductor, so that the arc can be transferred from the bent conductor segment to the fusible conductor without contact.

[0012] Since the fusible conductor and the deformed busbar have no permanent contact with each other and the fusible conductor is not integrated into the load current path under normal circumstances, it is possible to interrupt the load current path even in the event of a fault which does not provide sufficient energy for melting the fusible conductor. Such a situation can be, for example, a vehicle accident in which the load current path is disconnected without load.

[0013] In this case, the fusible conductor is positioned in particular such that the distance between the bent-back conductor section and the fusible conductor is smaller than the distance between the bent-back conductor section and the remainder of the conductor. That is, the conductor section is positioned in the bent state closer to the second connection of the fusible conductor than to the second conductor region. This ensures that the generated arc is reliably transferred to the fusible conductor and thus away from the remainder of the conductor and thus away from components of the high-voltage onboard electrical system.

[0014] In one embodiment of the invention, the separating element is designed as a separating piston and the separating unit has a guide cylinder, in which the separating piston is arranged and can be guided in the direction of the electrical conductor during acceleration. In the unactivated state, the pyrotechnic element holds the separating piston in an initial position of the guide cylinder, spaced apart from the electrical conductor. By activating the pyrotechnic element, the separating piston is no longer held, but moves in the guide cylinder in the direction of the electrical conductor into a final position. In this case, the separating piston cuts off the electrical conductor. For example, a piston seal can be provided between the separating piston and the guide cylinder.

[0015] In a further embodiment of the invention, the disconnecting unit has a brake block which is designed to brake the disconnecting element after the current conductor has been cut and thereby to predetermine the distance of the bent current conductor section relative to the fusible conductor. For example, the guide cylinder with the disconnecting piston can be arranged on one side of the current conductor and the brake block can be arranged on the other side of the current conductor relative to the guide cylinder with the disconnecting piston. The brake block is positioned in this case so that it brakes the disconnecting piston which bends the current conductor section in such a way that the bent current conductor section is positioned closer to the fusible conductor in the final position of the disconnecting piston than to the rest of the current conductor.

[0016] It can also be provided that the brake piston is elastically mounted so that after braking the separating piston, a brief contact can be established between the bent conductor section and the fusible conductor in order to improve the arc transfer. That is, the brake shoe is fastened by a spring, which is tensioned when the separating piston is braked and thus enables a brief contact between the fusible conductor and the conductor section. After a short time, the spring relaxes again and the brake shoe returns to a position in which the conductor section is spaced from the fusible conductor. The advantage of this embodiment is that the fusible conductor can be activated by the brief contact even when no arc is generated or when a sufficiently strong arc is not generated, and the arc can be transferred to the fusible conductor over a certain distance.

[0017] In a further embodiment of the invention, the electrical conductor has a desired breaking point for the separating element. The desired breaking point can be, for example, a tapering in the electrical conductor. That is, in the region of the desired breaking point, the electrical conductor has a reduced conductor cross section. In this way, the electrical conductor can be cut off more easily by the separating element in the event of a fault.

[0018] The invention further relates to a motor vehicle having a high-voltage onboard electrical system according to the invention. The motor vehicle is designed in particular as an electrically drivable motor vehicle.

[0019] The embodiments described with reference to the disconnect device according to the invention and their advantages apply correspondingly to the high-voltage onboard electrical system according to the invention and to the motor vehicle according to the invention.

[0020] Further features of the invention are apparent from the claims, the drawings and the description of the drawings. The features and feature combinations mentioned above in the description and the features and feature combinations mentioned subsequently in the description of the drawings and / or shown individually in the drawings can be used not only in the respectively indicated combination but also in other combinations or individually. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will now be further explained with the aid of preferred embodiments and with reference to the accompanying drawings. In the drawings:

[0022] Figure 1 A schematic diagram showing a first embodiment of a disconnect device for a high-voltage onboard power supply system in a normal situation;

[0023] Figure 2 Shown in accordance with Figure 1 Shutdown equipment in case of faults;

[0024] Figure 3 A schematic diagram showing a second embodiment of a disconnect device for a high-voltage onboard power supply system in a normal situation; and

[0025] Figure 4 Shown in accordance with Figure 3 Shutdown device in case of fault. DETAILED DESCRIPTION

[0026] In the figures, identical elements or elements having the same function are provided with the same reference symbols.

[0027] Figure 1 and Figure 2 Shown in normal conditions ( Figure 1 ) and in the event of a fault ( Figure 2) is a first embodiment of a disconnection device 1 for a high-voltage onboard power system of a motor vehicle under the present invention. By means of the disconnection device 1, components of the high-voltage onboard power system (not shown here) are electrically connected in a separable manner. The components may be, for example, a traction battery and an electric drive unit of a motor vehicle. The disconnection device 1 has an electrical conductor 2 in the form of a busbar, which in normal circumstances can conduct a load current in the form of an operating current between the components and thus constitute a load current path. The normal situation is characterized in particular in that the load current is not an overcurrent, that is, the load current is below a predetermined overcurrent threshold, and there is no accident of the motor vehicle, after which the components of the high-voltage onboard power system must be disconnected. In the event of a fault, that is, when an overcurrent flows through the electrical conductor 2 or when there is an accident or collision of the motor vehicle, the load current path should be interrupted.

[0028] For this purpose, the shut-off device 1 has a disconnecting unit 3, which has a pyrotechnic element 4 and a disconnecting element 5. The pyrotechnic element 4 is here an igniter 6, which can be ignited, for example, by a battery management system of the high-voltage onboard power supply. The disconnecting element 5 is here a disconnecting piston 7, which is arranged in a guide cylinder 8. A piston seal 9 is arranged between the disconnecting piston 7 and the guide cylinder 8. Figure 1 8 shows the separating piston 7 in an initial position in the guide cylinder 8, in which the separating piston 7 is held by the unlit or deactivated igniter 6. Figure 2 , the separating piston 7 is shown in the final position, in which the separating piston 7 is accelerated by the ignited or activated igniter 6. The separating unit 3 also has a brake shoe 10, which brakes the accelerated separating piston 7 once the separating piston has reached the final position. When transitioning from the initial position to the final position, the separating piston 7 cuts off the electrical conductor 2 and divides the electrical conductor into a first electrical conductor area 2a and a second electrical conductor area 2b. Here, the separating piston bends the electrical conductor section 11 of the first electrical conductor area 2a in the direction of the brake shoe 10. By cutting off the electrical conductor 2, the load current path is interrupted. For example, the electrical conductor 2 may also have a desired breaking point 12, which makes it easier for the separating piston 7 to cut off the electrical conductor 2.

[0029] In addition, the shutoff device 1 has an arc extinguishing unit 13, which is designed to receive and extinguish arcs generated when the shutdown load is high. For this purpose, the arc extinguishing unit 13 has a fusible conductor 14, which is embedded in an extinguishing agent 15 of the arc extinguishing unit 13. The fusible conductor 14 can be, for example, a perforated, conductive plate that melts for energy reduction during overcurrent. The extinguishing agent 15 extinguishes the melted fusible conductor 14. The fusible conductor 14 is not incorporated into the load current path under normal circumstances, that is, as long as the separation piston 7 is in the initial position. Here, the fusible conductor 14 is connected to the second conductor area 2b on one side and faces the brake pad 10 on the other side. In the final position of the separation piston 7 and therefore in the final position of the conductor section 11, the fusible conductor 14 can be incorporated into the load current path through the generated arc. For this purpose, the separating piston 7 places the electrical conductor section 11 in the vicinity of the fusible conductor 14, but the electrical conductor section 11 does not touch the fusible conductor 14. In other words, the fusible conductor 14 and the electrical conductor section 11 do not touch each other.

[0030] Here, the separating piston 7 and the brake shoe 10 are positioned relative to the fusible conductor 14 in such a way that the distance between the bent conductor section 11 and the fusible conductor 14 is smaller than the distance between the conductor section 11 and the second conductor region 2b. This ensures that the generated arc is transferred from the conductor section 11 to the fusible conductor 14, but not to the second conductor region 2b. The advantage of the disconnecting device 1 is that, due to the distance between the fusible conductor 14 and the bent conductor section 11, an interruption can also be achieved at a load current that is insufficient to provide energy for melting the fusible conductor 14. In this case, the interruption already occurs over the distance that occurs. Therefore, the solution provides a high disconnection capacity, which can also be used, for example, for no-load disconnection in vehicle accidents.

[0031] exist Figure 3 and Figure 4 In the normal case ( Figure 3 ) and in the event of a fault ( Figure 4 ) A second embodiment of the shut-off device 1 is shown. This second embodiment of the shut-off device 1 differs from the first embodiment of the shut-off device 1 in that the brake shoe 10 is secured by a spring 16. When the separation piston 7 is braked, the brake shoe 10 is moved downward by the spring 16, so that a brief electrical contact can be produced between the bent conductor section 11 and the fusible conductor 14. This makes it possible to reliably transfer the arc to the fusible conductor 14. After a short time, a defined distance is again established between the fusible conductor 14 and the bent conductor section 11, and the components are electrically separated.

Claims

1. A disconnect device (1) for a high-voltage onboard power system of a motor vehicle, the disconnect device comprising: - an electrical conductor (2) for forming a load current path between components of the high-voltage onboard electrical system, - a pyrotechnically activatable disconnecting unit (3) for interrupting a load current path in the event of a fault, the disconnecting unit having a disconnecting element (5) and a pyrotechnical element (4), wherein: The pyrotechnic element (4) is designed to accelerate the disconnecting element (5) in the direction of the electrical conductor (2) in the event of a fault, and the disconnecting element (5) is designed to disconnect the electrical conductor (2) in order to interrupt the load current path. It is characterized in that an arc extinguishing unit (13) for extinguishing an arc generated when interrupting a load current path, the arc extinguishing unit having a fusible conductor (14) which is not normally integrated into the load current path and having an extinguishing agent (15) for extinguishing the fusible conductor (14), The separating element (5) is designed to bend the conductor section (11) in the direction of the fusible conductor (14) in order to transfer the generated arc to the fusible conductor (14) when the conductor (2) is cut, and thereby to connect the fusible conductor (14) into the load current path in the event of an arc-causing fault, wherein the bent conductor section (11) and the fusible conductor (14) are arranged at least temporarily without contact with each other during the arc transfer.

2. The shut-off device (1) according to claim 1, characterized in that The fuse conductor (14) is positioned such that the distance between the bent conductor section (11) and the fuse conductor (14) is smaller than the distance between the bent conductor section (11) and the remaining part of the conductor (2).

3. The shut-off device (1) according to claim 1 or 2, characterized in that The fusible conductor (14) is positioned such that the bent-back conductor section (11) is permanently spaced apart from the fusible conductor (14), so that an arc can be transferred from the bent-back conductor section (11) to the fusible conductor (14) without contact.

4. The shut-off device (1) according to claim 1 or 2, characterized in that The separating element (5) is designed as a separating piston (7) and the separating unit (3) has a guide cylinder (8) in which the separating piston (7) is arranged and can be guided in the direction of the electrical conductor (2) during acceleration.

5. The shut-off device (1) according to claim 1 or 2, characterized in that The separating unit (3) has a braking shoe (10) which is designed to brake the separating element (5) after the electrical conductor (2) has been cut and thereby to limit the distance of the bent electrical conductor section (11) relative to the fusible conductor (14).

6. The shut-off device (1) according to claim 5, characterized in that The brake block (10) is elastically mounted so that after the conductor segment (11) is bent, a short-term contact can be established between the bent conductor segment (11) and the fuse conductor (14) for improving arc transfer.

7. The shut-off device (1) according to claim 1 or 2, characterized in that The fire extinguishing agent (15) is configured as extinguishing sand.

8. The shut-off device (1) according to claim 1 or 2, characterized in that The electrical conductor (2) has a desired breaking point (12) for separating the element (5). 9 . A high-voltage onboard electrical system for a motor vehicle, comprising at least two components and at least one disconnect device ( 1 ) for electrically connecting the components. 10 . A motor vehicle having a high-voltage onboard electrical system as claimed in claim 9 .

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