Pyrotechnic shutdown device for a multi-core power cable of a high-voltage electrical system

Abstract

The invention relates to a disconnect device (6) for an electrical line (2) of a high-voltage electrical system, comprising a pyrotechnically activated disconnect unit (7) for interrupting a load current path formed via the electrical line (2), a disconnect element (10) for cutting the electrical line (2) into two line parts (2a, 2b), and a pyrotechnic ignition element for moving the disconnect element (10) from an initial position (P1) to a disconnect position (P2), in which the disconnect element (10) is arranged between the two line parts (2a, 2b) of the electrical line (2) after cutting, wherein the disconnect device (6) for cutting an electrical line (2) is designed in the form of a power cable (3) having at least two conductors (4a, 4b) and is mountable on the power cable (3) for this purpose, wherein the disconnect element (10) is located at least in a disconnect area (22), which in the disconnect position (P2) is located between the two cable sections (2a,2b) is arranged, having an electrically insulating first side (22a) designed to electrically insulate the conductors (4a, 4b) of one conductor part (2a), and having an electrically conductive second side (22b) designed to short-circuit the conductors (4a, 4b) of the other conductor part (2b).

Description

[0001] The invention relates to a disconnection device for an electrical line of a high-voltage vehicle electrical system. The disconnection device has a pyrotechnically activated disconnection unit for interrupting a load current path formed via the electrical line. The disconnection unit comprises a disconnection element for severing the electrical line into two line sections and a pyrotechnic ignition element for transferring the disconnection element from an initial position to a disconnection position, in which the disconnection element is arranged between the two line sections of the electrical line after being severed. The invention also relates to an assembly and a high-voltage vehicle electrical system.

[0002] In this case, the focus is on high-voltage electrical systems of motor vehicles, for example, electrified vehicles. Such high-voltage electrical systems comprise multiple electrical system components or high-voltage components, which can be configured, for example, as a traction battery and at least one high-voltage consumer in the form of an auxiliary unit. The electrical system components are electrically connected via an electrical line for load current transmission. In the event of a fault, for example, an overcurrent or fault current flowing through the line or in the event of a motor vehicle accident, the electrical system components must be reliably disconnected from one another.

[0003] For this purpose, it is known from the prior art, for example from DE 10 2020 104 935 A1, to provide shutdown devices with disconnecting units that can interrupt the load current path formed between the components via a busbar. The disconnecting units can be activated pyrotechnically, for example. For this purpose, the disconnecting units have a pyrotechnic ignition element and a disconnecting element. The pyrotechnic ignition element is ignited, i.e. activated, in the event of a fault and accelerates the disconnecting element toward the busbar, which then severs the busbar and thus interrupts the load current path. The shutdown device known from the prior art is designed for the specific application of interrupting a busbar.In addition, the disconnecting device has a busbar section that must be severed, so that in order to install the disconnecting device in the load current path, the busbar must be broken open to accommodate the busbar section of the disconnecting device. This is both complex and creates contact resistance in the area of ​​the busbar section.

[0004] It is an object of the present invention to provide a solution as to how a load current path of a high-voltage vehicle electrical system can be safely and reliably interrupted and how the high-voltage vehicle electrical system can also be transferred to a safe state.

[0005] This object is achieved according to the invention by a shutdown device, an assembly, and a high-voltage electrical system having the features according to the respective independent patent claims. Advantageous embodiments of the invention are the subject of the dependent patent claims, the description, and the figures.

[0006] A shutdown device according to the invention for an electrical line of a high-voltage vehicle electrical system has a pyrotechnically activatable disconnecting unit for interrupting a load current path formed via the electrical line. The pyrotechnic disconnecting unit has a disconnecting element for severing the electrical line into two line sections and a pyrotechnic ignition element for transferring the disconnecting element from an initial position to a disconnecting position in which the disconnecting element is arranged between the two line sections of the electrical line. The shutdown device is designed to sever an electrical line in the form of a power cable having at least two wires and can be mounted on the power cable for this purpose.The separating element has, at least in a separating region which is arranged in the separating position between the two line parts, an electrically insulating first side which is designed to electrically insulate the wires of one line part, and an electrically conductive second side which is designed to short-circuit the wires of the other line part.

[0007] The invention also relates to an assembly for a high-voltage on-board electrical system of a motor vehicle. The assembly has a multi-core power cable for electrically connecting at least two components of the high-voltage on-board electrical system and a shutdown device according to the invention which is separate from the power cable and is mechanically connected to the power cable in a non-destructively detachable manner. A high-voltage on-board electrical system according to the invention for a motor vehicle has at least two on-board electrical system components and at least one assembly according to the invention, wherein the two on-board electrical system components are electrically connected to the multi-core power cable. The shutdown device is designed in particular to transfer the high-voltage on-board electrical system to an intrinsically safe state in the event of a fault, for example in the event of an accident involving the motor vehicle. For this purpose, the shutdown device can switch on at least one on-board electrical system component orDisconnect a high-voltage component in the form of a high-voltage auxiliary unit by separating it from an on-board network component in the form of a high-voltage storage device, thereby also enabling the discharge of intermediate circuit capacitances of the high-voltage on-board network. For this purpose, the disconnection device is designed to sever or cut the multi-core power cable connecting the on-board network components, thereby short-circuiting the cores at one end.

[0008] For this purpose, the shutdown device has the pyrotechnically activated separation unit with the pyrotechnic ignition element and the separation element. The separation element can be moved by an ignition process of the pyrotechnic ignition element. The ignition process of the pyrotechnic ignition element can be initiated via an ignition signal. The separation element is thereby accelerated from its initial or rest position towards the power cable and severs it into two power cable parts or sections. In the separation or final position, in which the power cable is severed, a region of the separation element or the separation region is arranged between two power cable sections. The first side of the separation region touches the ends of the wires of one, first power cable part, and the opposite second side of the separation region touches the ends of the wires of the other, second power cable part.The first side is designed to be electrically insulating, so that the ends of the wires of the first power cable part touch the electrically insulating side of the isolating element, and thus the wires of the first power cable section are electrically insulated from one another when the load current path is interrupted. The first power cable section is connected, in particular, to the high-voltage storage device, so that the wires on the high-voltage storage side are electrically insulated after the load current path is interrupted. The second side is designed to be electrically conductive, so that the ends of the wires of the second power cable part touch the electrically conductive side of the isolating element, and the wires of the second power cable section are short-circuited when the load current path is interrupted.The second power cable section is in particular connected to at least one auxiliary unit, so that the unit-side wires are short-circuited after the interruption of the load current path in order to discharge the intermediate circuit capacitances.

[0009] Such a separating element enables a particularly simple and cost-effective solution for transferring the high-voltage electrical system into a safe state.

[0010] For example, the separating element can comprise a separating piston made of an electrically conductive material, such as iron, which is partially coated with an electrically insulating material. The separating piston has, for example, a cutting edge and can be wedge-shaped, for example. The separating piston can be arranged in a guide cylinder, for example, one that runs perpendicular to the length of the line, in which the separating piston is displaced linearly by the ignition process.

[0011] Particularly preferably, the shutdown device has a housing for mounting on the power cable, in which the pyrotechnically activatable separation unit is arranged and which is designed to receive and enclose a section of the power cable to be severed. The shutdown device can thus be mechanically connected to the power cable via the housing in a non-destructively detachable manner and in doing so encloses the power cable in sections. By arranging the housing on the power cable, the separation unit is arranged on the power cable in such a way that the separation element, in the initial position, is arranged at a distance from or only adjacent to an insulating sheath of the section of the power cable arranged in the housing. An upper side of the housing can have an interface, for example in the form of a plug-in connector, which is connected to the pyrotechnic ignition element within the housing and can be connected to an ignition signal generator outside the housing.The shutdown device can therefore be conveniently mounted on the power cable without having to disconnect the power cable. Such a shutdown device is designed to be particularly simple and flexible.

[0012] In particular, the housing is designed in two parts for arrangement on the power cable, wherein housing parts of the housing have mutually corresponding connecting elements via which the housing parts can be mechanically connected after arrangement on the power cable. The housing has a first housing part, for example an upper housing part, and a second housing part, for example a lower housing part, which can be assembled on the power cable and in doing so enclose the power cable. The guide cylinder, in which the separating element and the ignition element are arranged, can be located in one of the housing parts. For example, the housing parts have half-hole-like openings in mutually facing edges on two opposite housing walls, which, when the housing parts are joined together, form cable clamp-like through-openings for passing the power cable through the housing.The half-hole-like openings are arranged on the end walls of the housing parts, which are axially opposite one another along the cable length. When the housing parts are joined together, they are placed like a cable clamp around the section of the power cable to be severed and can, in particular, also be detached from the power cable again. The connecting elements of the housing parts, which can be arranged, for example, transversely to the cable length on opposite housing walls of the housing parts, can form a snap connection and / or be connectable via a screw connection. For example, one of the housing parts can have snap hooks which, with locking lugs or locking openings on the other housing part, form the detachable snap connection. Both housing parts can also have tabs which can be positioned flush with one another and connected by means of a screw.When closed, the housing is designed to be particularly liquid-tight. Sealing elements can be located in the area of ​​the through-holes to prevent liquid from penetrating the housing.

[0013] The housing can also be provided with clamping elements for securing the section of the power cable to be severed within the housing. The clamping elements can, for example, be arranged as jaw-like elements in the area of ​​the through-openings, thereby holding the section of the power cable to be severed in a tensioned state. This allows the severing element to reliably sever the power cable without causing it to shift.

[0014] In a further development of the invention, the disconnection device has a shielding section that can be connected to shielding sections of the power cable to provide continuous shielding, wherein the separating element is arranged at a distance from the shielding section of the disconnection device to prevent severance of the shielding in the disconnected position. The disconnection device of this embodiment is intended for shielded power cables in which the shielding can be maintained despite an interruption of the load current path to prevent an insulation fault. For this purpose, the disconnection device has part of the shielding. The section of the power cable to be severed has no shielding. When the disconnection device is arranged on the power cable, the shielding section of the disconnection device is connected to the interrupted shielding of the power cable, thus restoring the continuous shielding.The shielding section is arranged in particular in the second housing part of the housing and is not severed by the separating element when the wires of the power cable are severed.

[0015] The embodiments presented with reference to the shutdown device according to the invention and their advantages apply accordingly to the assembly according to the invention and to the high-voltage vehicle electrical system according to the invention.

[0016] Further features of the invention emerge from the claims, the figures, and the description of the figures. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures, can be used not only in the respective specified combination, but also in other combinations or on their own.

[0017] The invention will now be explained in more detail using a preferred embodiment and with reference to the drawings. They show: Fig. 1a, Fig. 1b is a schematic sectional view of an assembly with a power cable and a first embodiment of a shutdown device; Fig. 2a, Fig. 2b is a schematic sectional view of an assembly with a power cable and a second embodiment of a shutdown device, and Fig. 3 a top view of the assembly.

[0018] In the figures, identical and functionally identical elements are provided with the same reference numerals.

[0019] Fig. 1a, Fig. 1b and Fig. 2a, Fig. 2b show different designs of an assembly 1 for a high-voltage electrical system of a motor vehicle. Fig. 3 shows a top view of the assembly 1. The assembly 1 has an electrical line 2 in the form of a multi-core power cable 3, which here comprises two wires 4a, 4b and an insulation 5 encasing the wires 4a, 4b and connects two on-board network components B1, B2, for example a high-voltage energy storage device B1 and an auxiliary unit B2, of the high-voltage on-board network. Furthermore, the assembly 1 has a shutdown device 6, which is designed as a pyrotechnic cable cutter. The shutdown device 6 has a pyrotechnic separation unit 7, which is arranged in a housing 8 of the shutdown device 6. The separation unit 7 comprises a pyrotechnic ignition element 9, a so-called squib or ignition capsule. The separation unit 7 also comprises a separation element 10, which here has a metallic separation piston 11 with an electrically insulating coating 12.The separating piston 11 is arranged in a guide cylinder 13 and is driven there by the ignition element 9 from an initial position P1 (see . Fig. 1a, Fig. 2a) into a separation position P2 (see Fig. 1b, Fig. 2b) movable.

[0020] The housing 8 is constructed in two parts and comprises a first housing part 8a and a second housing part 8b. The housing parts 8a, 8b are connected to one another in a liquid-tight and non-destructive manner and enclose a section 14 of the power cable 3. The section 14 is not part of the shutdown device 6, but rather the shutdown device 6 is attached to the power cable 3 via the housing 8. To attach the housing 8 to the power cable 3, the two housing parts 8a, 8b are joined and connected in such a way that the section 14 is arranged between them and thus within the housing 8. The housing parts 8a, 8b have corresponding connecting elements 15a, 15b (see Fig. 3), which form, for example, a snap connection or a screw connection. Furthermore, the housing parts 8a, 8b have half-hole-like openings, which, when the housing parts are assembled, form through-openings 16 in opposing housing walls 17, 18, through which the power cable 3 can be guided through the housing 8. In the area of ​​the through-openings 16, the housing 8 also has clamping elements 19, which are designed to hold the section 14 in a tensioned state and also to prevent the shutdown device 6 from slipping or twisting.

[0021] In the initial position P1, the pyrotechnic ignition element 9 is unignited, and a cutting edge 20 of the separating element 8 is arranged at a distance from or adjacent to the insulation 5 of the power cable 3. The power cable 3 is intact and electrically connects the two on-board power supply components B1, B2. In the event of a fault, for example in the event of a motor vehicle accident, the high-voltage on-board power supply is to be transferred to an intrinsically safe state. For this purpose, the on-board power supply components B1, B2 are to be separated from one another, and intermediate circuit capacitances of a high-voltage intermediate circuit of the high-voltage on-board power supply are to be discharged. For this purpose, the ignition element 9 is ignited by means of an ignition signal, which can be supplied to the ignition element 9 via an interface 21 arranged in the housing 8. The ignition element 9 can be connected to an ignition signal generator outside the housing 8 via the interface 21, which can be a connector, for example.Due to the ignition process, the separating element 11 moves in the direction of the power cable 3 due to the pressure change, cuts through the power cable 3 and is arranged in the end position P2 between two line parts 2a, 2b in the form of two power cable parts 3a, 3b of the power cable 3.

[0022] The separating region 22 of the separating element 11, located between the power cable parts 3a, 3b, has the electrically insulating coating 12 on one side 22a, here on the side facing the power cable part 3a, which is connected to the vehicle electrical system component B1, so that the wires 4a, 4b of this first power cable part 3a are electrically insulated from one another. On the other side 22b, here on the side facing the power cable part 3b, which is connected to the vehicle electrical system component B2, the separating region 22 is electrically conductive, for example, uncoated, so that the wires 4a, 4b of this power cable part 3b are electrically connected and thus short-circuited.

[0023] In the design of the switch-off device 7 according to Fig. 2a, Fig.2b, the disconnection device 7 has a shielding section 23, which is electrically connected to shielding sections 24 of the power cable 3. The shielding sections 23, 24 form a continuous shielding 25 of the power cable 3. When the housing 8 is mounted on the power cable 3, which is unshielded in section 14, the shielding section 23 is electrically connected to the shielding sections 24 of the power cable. In the disconnection position P2, the disconnection element 10 is arranged at a distance from the shielding section 23. Thus, the disconnection element 10 has severed the wires 4a, 4b, but not the shielding 25, so that no insulation fault is caused by the disconnection device 7. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2020 104 935 A1

[0003]

Claims

[1] Switch-off device (6) for an electrical line (2) of a high-voltage vehicle electrical system, comprising a pyrotechnically activatable separating unit (7) for interrupting a load current path formed via the electrical line (2), with a separating element (10) for severing the electrical line (2) into two line parts (2a, 2b) and a pyrotechnic ignition element for transferring the separating element (10) from an initial position (P1) into a separating position (P2), in which the separating element (10) is arranged between the two line parts (2a, 2b) of the electrical line (2) after the severing, characterized byin that the disconnection device (6) for severing an electrical line (2) is designed in the form of a power cable (3) having at least two wires (4a, 4b) and can be mounted on the power cable (3) for this purpose, wherein the separating element (11) has, at least in a separating region (22) which is arranged in the separating position (P2) between the two line parts (2a, 2b), an electrically insulating first side (22a) which is designed to electrically insulate the wires (4a, 4b) of one line part (2a), and an electrically conductive second side (22b) which is designed to short-circuit the wires (4a, 4b) of the other line part (2b). [2] Switch-off device (6) according to claim 1, characterized by that the separating element (10) has a separating piston (11) made of an electrically conductive material, which is partially coated with an electrically insulating material. [3] Switch-off device (6) according to claim 1 or 2, characterized by that the shutdown device (6) has a housing (8) for mounting on the power cable (3), in which the pyrotechnically activatable separation unit (7) is arranged and which is designed to receive and enclose a section (14) of the power cable (3) to be severed. [4] Switch-off device (6) according to claim 3, characterized by that the housing (8) is designed in two parts for arrangement on the power cable (3), wherein housing parts (8a, 8b) of the housing (8) have mutually corresponding connecting elements (15a, 15b) via which the housing parts (8a, 8b) can be mechanically connected after arrangement on the power cable (3). [5] Switch-off device (6) according to claim 4, characterized by that the connecting elements (15a, 15b) form a snap connection and / or can be connected via a screw connection. [6] Switch-off device (6) according to claim 4 or 5, characterized by that the housing parts (8a, 8b) have half-hole-like openings in two opposite housing walls (17, 18) on mutually facing edges, which, in the assembled state of the housing parts (8a, 8b), form cable clamp-like through-openings (16) for passing the power cable (3) through the housing (8). [7] Switch-off device (6) according to one of claims 4 to 6, characterized by that the housing (8) has clamping elements (19) for fixing the section (14) of the power cable (3) to be severed in the housing (8). [8] Switch-off device (6) according to one of the preceding claims, characterized byin that the shutdown device (6) has a shielding section (23) which can be connected to shielding sections (24) of the power cable (3) to provide a continuous shielding (25), wherein the separating element (10) is arranged at a distance from the shielding section (23) of the shutdown device (6) to prevent the shielding (25) from being severed in the separating position (P2). [9] Assembly (1) for a high-voltage electrical system of a motor vehicle, comprising - a multi-core power cable (3) for electrically connecting at least two on-board network components (B1, B2) of the high-voltage on-board network and a shutdown device (6) according to one of the preceding claims, wherein the shutdown device (6) is detachably mechanically connected to the power cable (3). [10] High-voltage electrical system for a motor vehicle comprising at least two electrical system components (B1, B2) and at least one assembly (1) according to claim 9.

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