Device comprising a passive fault-current protection device and cooling device for a fluid cooling of a passive fault-current protection device

Abstract

The invention relates to a cooling device for a fluid cooling of a passive fault-current protection device, preferably a high-voltage fuse. The invention additionally relates to a device for protecting a high-voltage current circuit of a vehicle, comprising such a cooling device and a passive fault-current protection device. The passive fault-current protection device (3) comprises a fuse body (4) with a connection conductor (5) arranged therein, wherein the fuse body (4) has a respective connection contact (6) at both ends, said connection contact being connected to the connection conductor (5). The cooling device (1) comprises a heat sink (2), two connection regions (7) which are arranged on opposite sides of the heat sink (2) for receiving the connection contacts (6), two fluid connections (4), and a cooling channel (9) which fluidically connects the two fluid connections (8) and runs in the interior of the heat sink (2). The heat sink (2) has a recess (10), preferably a trough-like recess, between the connection regions (7) for at least partly receiving the fuse body (4) in a laminar manner. The cooling channel (9) runs along at least one lateral wall of the recess (10). By virtue of the aforementioned cooling device, an effective active fluid cooling can be provided for the passive fault-current protection device such that the maximum current flow running through a charging circuit, in particular a high-voltage charging circuit, can be advantageously increased.

Description

[0001] The invention relates to a device for protecting a high-voltage circuit of a vehicle, comprising a passive residual current device and a cooling device for fluid cooling of the passive residual current device.

[0002] The advancement of e-mobility, particularly in the commercial vehicle sector, demands ever-increasing charging capacities for the rapid charging of high-voltage vehicle batteries. Passive residual current devices (RCDs), usually in the form of high-voltage fuses, are used to protect the charging circuit. These RCDs, in combination with high-voltage contactors, are used in the vehicle's charging path to provide electrical protection for the charging circuit between the charging station and the electric vehicle. The high-voltage fuses must be able to safely carry high charging currents while simultaneously ensuring rapid disconnection of the residual current circuit in the event of a short circuit. These requirements (high current-carrying capacity on the one hand and rapid disconnection of the residual current on the other) are inherently conflicting and can only be met at the expense of one or the other.The two charging standards ISO17409 and ISO5474-3, for example, specify limit values ​​for the maximum permissible fault current for the charging circuit.

[0003] Practical approaches exist where the cooling of the passive residual current device (RCD) is passive, primarily via the copper busbars connected for electrical contact. A disadvantage of this approach is that the possible continuous charging currents are limited, as thermal overload of the fuse can occur during normal charging operation. Furthermore, it is not possible to conduct charging currents exceeding 1,000 A through the high-voltage fuse using this method. Simply increasing the size of the high-voltage fuse would result in violations of the specified limit values ​​of the ISO standards.

[0004] Special actively fluid-cooled circuit arrangements with a fuse are also known from the prior art. For example, patent application WO 2018 / 069141 A1 describes a circuit arrangement with a fuse in which the fuse is formed as a layered arrangement on a heat sink. The layered arrangement is guided over a bridge element formed by two material recesses in the heat sink. To provide the melting point of the layered arrangement, a heat build-up is deliberately induced in the area of ​​the bridge element. The melting point, i.e., the current at which the conductor layer melts, can be determined by adjusting the width and shape of the bridge element, as well as by the layer thicknesses and the selected conductor material of the layered arrangement.A disadvantage of this arrangement is that for each application requiring a residual current device, a new, complex dimensioning of the bridge element and the layer arrangement is necessary, meaning that only special designs of fuses can be used.

[0005] US 3,453,579 A discloses a fuse with an insulating body. The insulating body is provided with an axial channel for the flow of a cooling fluid such as air or demineralized water, the fuse's fusible elements being arranged in channels parallel to and surrounding this cooling channel. The fuse's electrical terminals are annular in the case of air cooling; in the case of cooling fluid, they cover the terminals.

[0006] FR 1 337 709 A discloses an electrical switching device with safety elements housed in plastic enclosures. The plastic enclosures have openings for the flow of coolant. In a switching device with horizontally arranged safety elements, coolant channels may be provided that open into a nearly vertical shaft. This ensures a continuous flow of air or gas cooling along the surface of the safety elements.

[0007] It is therefore an object of the invention to provide a technology that avoids the disadvantages of existing solutions or at least reduces these disadvantages. This object is achieved by the device for protecting a high-voltage circuit of a vehicle with the features of independent claim 1. Advantageous further developments are specified in the dependent claims and the description.

[0008] According to a general aspect of the invention, a cooling device for fluid cooling of a passive residual current device (RCD) is provided. The passive RCD comprises a fuse body with a connecting conductor arranged therein. The fuse body has a terminal contact at each end, which is connected to the connecting conductor. In a preferred embodiment, the passive RCD is designed as a high-voltage fuse. In this case, the connecting conductor is a fusible link.

[0009] The cooling device according to the invention comprises a heat sink, two connection areas arranged on opposite sides of the heat sink for receiving the connection contacts of the passive residual current protection device, two fluid connections, preferably for connection to a coolant circuit of a motor vehicle, and a cooling channel for a cooling fluid running inside the heat sink, fluidically connecting the two fluid connections.

[0010] The heat sink has a recess, for example a depression, between the connection areas for the section-by-section, surface-mounted reception of the fuse element. The cooling channel runs along at least one side wall of the recess. A recess for the section-by-section, surface-mounted reception of the fuse element is understood to mean that the fuse element is placed and / or can be inserted into the recess and rests there with at least one section of the fuse element in a surface-mounted contact, i.e., forms a surface contact within the recess with the wall of the heat sink. For this purpose, the recess is preferably designed in a trough-like (trough-like) shape.

[0011] The described cooling device enables advantageous active fluid cooling of a passive residual current device (RCD). This allows the use of a smaller high-voltage fuse with a fast tripping characteristic, which complies with the limits of the ISO standards and, thanks to the active fluid cooling, is not thermally overloaded or prone to tripping at high DC charging currents exceeding 1,000 A. The cooling device allows the cooling fluid to be advantageously guided laterally past the passive RCD through the cooling channel, while simultaneously achieving effective thermal coupling via the surface contact between the cooling element and the passive RCD. This enables particularly effective fluid cooling of the passive RCD.Furthermore, this cooling device makes it possible to cool standardized, commercially available high-voltage fuses, thus achieving cost-effective and economical use.

[0012] The cooling element can be connected to a coolant circuit via the fluid ports, allowing coolant to flow into the cooling channel through one port and out through the other. This cooling of the fuse body increases the maximum current flow through the charging circuit. For example, the cooling increases the continuous current that the fuse can carry.

[0013] In a preferred embodiment of the cooling device, the cooling channel is routed around the recess and / or has a U-shaped profile. This improves the active cooling effect of the heat sink, particularly enabling effective cooling of the recess's side wall. Alternatively or additionally, the fluid connections can be arranged at the same end of the heat sink relative to the recess. This allows for the longest possible cooling path and also facilitates easy connection of the cooling device to a coolant circuit, keeping the required coolant lines as short as possible. Preferably, the connection areas of the cooling device can each have a flat contact surface and / or a hole, preferably an elongated hole, for the positive locking and electrical contacting of the connection contacts.This is particularly advantageous for accommodating busbar-style terminals. The flat contact surfaces of the terminals serve as a support surface for the busbars. A screw can be inserted through the hole, allowing the busbar to be securely and firmly attached to the heat sink. The use of suitable, electrically conductive materials simultaneously ensures electrical contact. The use of an elongated hole instead of a circular one allows for greater installation flexibility.

[0014] Preferably, the heat sink is made of a thermally conductive, electrically insulating material. This material can be, for example, plastic or ceramic. A thermally conductive material enables particularly good and uniform cooling of the fuse body, while the choice of an electrically insulating material contributes to protection against short circuits in the entire charging circuit.

[0015] According to the invention, a device for protecting a high-voltage circuit of a vehicle, in particular a motor vehicle, is provided. This device for protecting a high-voltage circuit is hereinafter referred to simply as the device. The device comprises a passive residual current device, preferably a high-voltage fuse, and a cooling device for fluid cooling of the passive residual current device, as described above. That is, the passive residual current device has a fuse body with a connecting conductor arranged therein, the fuse body having a terminal contact at each end that is connected to the connecting conductor.

[0016] In a preferred embodiment, the section of the locking element received in the recess is at least partially in planar contact with a wall of the recess. This planar contact of the locking element with the wall of the recess enables effective and uniform cooling of the locking element, as explained above.

[0017] According to the invention, the surface shape and dimensions of the recess correspond to the surface shape and dimensions of the section of the locking element received in the recess. This allows for the largest possible surface contact between the heat sink and the locking element.

[0018] It was established above that the recess can be designed in a trough-like shape. An advantageous embodiment of this design provides that the trough-like recess is shaped so that a locking element can be inserted, at least partially. The contour of the recess can be shaped to follow or be adapted to the outer contour of the locking element, ensuring the largest possible contact area between the outer surface of the locking element and the side wall of the recess. The locking element does not need to be completely recessed into the heat sink. It is also possible for the lower part of the locking element to be inserted into the heat sink, with the other part protruding above it. In this case, the contour of the side wall of the recess follows the portion of the locking element that is to be recessed into the recess.To ensure that the contour of the side wall of the recess follows the outer contour of the fuse body, the contours do not necessarily have to be identical. For example, manufacturing-related rounding or flattening, as well as additional recesses for routing contacts in the area of ​​the heat sink recess, may be provided.

[0019] A standard high-voltage fuse, commonly used in practice, can be employed. Commercially available versions include those with a cylindrical fuse body (high voltage round body fuses) and those with a rectangular fuse body (high voltage square body fuses).

[0020] The fuse body can be cylindrical, as is typical for high-voltage fuses – this is merely an example. The contact surface of the recess for the fuse body is then cylindrical segment-shaped. A cylindrical segment is a circular segment that has been linearly extruded along the normal vector of the circular segment's area. Alternatively, the fuse body and the recess for the fuse body can each be cuboid-shaped. The edges of the cuboids can be rounded. The edge lengths of the cuboid fuse body and the cuboid recess do not have to be identical. The advantage of these designs is the ability to use commercially available passive residual current devices (RCDs) that have cylindrical or cuboid fuse bodies.The corresponding cylindrical segment-shaped support of the recess or the cuboid-shaped recess enable efficient and uniform cooling of these commercially available locking elements.

[0021] However, it is emphasized that the design of the recess or its contact surface is not limited to these two variants and may accordingly have a different shape, especially in the case that a high-voltage fuse is to be cooled which has a fuse body design that deviates from the cuboid or cylindrical shape.

[0022] In a further preferred embodiment, the device comprises two cooling devices for fluid cooling of the passive residual current device, wherein the two cooling devices, in particular their heat sinks, are stacked on top of each other rotated 180° relative to each other, so that the two recesses of the two cooling devices surround the fuse body like a shell. In this way, the fuse body can be cooled uniformly from all sides, so that no heat build-up occurs within the fuse body. Accordingly, the cooling can be further improved. Furthermore, a modular approach is realized, since the device is modularly constructed from two, preferably identical, cooling devices.

[0023] The two fluid connections of the stacked cooling devices can each be arranged such that the two cooling devices are fluidically connected and / or connectable to an external cooling circuit via these fluid connections, either in parallel or in series. If the cooling devices are to be fluidically connected in parallel to an external cooling circuit, then each cooling device has two dedicated fluid connections to the external cooling circuit. If, on the other hand, the two cooling devices are to be fluidically connected in series to an external cooling circuit, then the two stacked cooling channels are fluidically connected via two of the fluid connections, while one of the remaining two fluid connections serves as the inlet connection and the other as the outlet connection with respect to the external cooling circuit.

[0024] The option of connecting the cooling channels in series or parallel allows for consideration of the external cooling circuit's design. Factors such as the type of tubing, available space, and coolant temperature can play a role. For example, if space for routing tubing is very limited, a fluidic series connection with a total of two fluid connections on the outer sides may be advantageous, requiring only two external fluid lines. Conversely, if the temperature stability of the fuse body is particularly critical, a fluidic parallel connection of the two cooling elements could be chosen.

[0025] Furthermore, in another embodiment of the device, a thermal paste or thermal pad can be provided between the fuse body and the wall of the recess to improve thermal contact. If the shape of the recess's side wall does not perfectly match the surface of the fuse body, for example due to manufacturing defects or different surface textures, the thermal paste or thermal pad can optionally compensate for the irregularities, ensuring maximum thermal contact between the heat sink and the fuse body.

[0026] According to another aspect of the invention, a motor vehicle is provided, comprising a cooling device according to one of the previously described embodiments. Preferably, the motor vehicle is a commercial vehicle. In other words, the vehicle can be a vehicle whose design and equipment are intended for transporting persons, goods, or towing trailers. Preferably, the vehicle is a tractor unit, i.e., a vehicle for pulling a semi-trailer. Particularly preferably, the vehicle is a tractor unit without an attached semi-trailer.

[0027] The preferred embodiments and features of the invention described above can be combined in any way desired. Further details and advantages of the invention are described below with reference to the accompanying drawings.

[0028] They show Figure 1 is a schematic perspective view of a device for protecting a high-voltage circuit of a vehicle according to one embodiment; Figure 2 is a schematic view of a high-voltage fuse; and Figure 3 is a schematic view of an embodiment in which two heat sinks are stacked on top of each other rotated by 180° relative to each other.

[0029] Figure 1 Figure 1 shows a schematic perspective representation of a device 13 for securing a high-voltage circuit of a vehicle, in particular a motor vehicle.

[0030] The device 13 comprises a cooling device 1 for fluid cooling of a passive residual current protection device, preferably a high-voltage fuse.

[0031] The cooling device 1 comprises a heat sink 2, two connection areas 7 arranged on opposite sides of the heat sink 2 for receiving the connection contacts of a conventional high-voltage fuse, two fluid connections 8, and a cooling channel 9 running inside the heat sink 2 which fluidically connects the two fluid connections 8 and provides cooling fluid.

[0032] The cooling channel 9 has a U-shaped profile and extends along the side walls of the recess 10. The heat sink 2 is characterized by a trough-like recess 10 arranged between the connection areas 7, which serves for the section-by-section, planar reception of the high-voltage fuse, in particular for the planar reception of the fuse body 4 of the high-voltage fuse, which will be explained below.

[0033] In Figure 1Only the fuse body 4 of the high-voltage fuse is partially shown. The high-voltage fuse 3 is in Figure 2 schematically represented. As in Figure 2 As shown, the high-voltage fuse 3 comprises a fuse body 4 with a connecting conductor 5, also referred to as a fusible link, running within it, which connects the two ends of the fuse body 4. The fuse body 4 has a terminal contact 6 at each end, which is electrically connected to the connecting conductor 5.

[0034] Should the current flow in the circuit become too high, for example due to a short circuit, the temperature of the connecting conductor 5 rises above its melting point, causing the connecting conductor 5 to melt and thus interrupting the circuit. The casing of the fuse body 4 consists of an electrically insulating material, so that the arc that occurs when the circuit is interrupted is absorbed by the fuse body, thus protecting the rest of the circuit from further damage. Often, the fuse bodies are additionally filled with a granular material such as quartz sand to extinguish the arc as quickly and reliably as possible. Such high-voltage fuses 3 are known from the prior art and are frequently used with cylindrical (as in Figure 2 shown) or cuboid-shaped safety bodies 4.

[0035] Referring again to Figure 1The fuse body 4 of a cylindrical high-voltage fuse is schematically indicated by the two circles. The heat sink 2 of the cooling device 1 consists of a thermally conductive, electrically insulating material, for example, plastic or a ceramic material. The coolant for the cooling channel 9 is supplied by an external cooling circuit (not shown). The external cooling circuit is connected to the cooling channel 9 via the two fluid connections 8. The coolant flows into the cooling channel 9 through one of the fluid connections 8, cools the material of the heat sink 2 there, and then flows back into the external cooling circuit through the other fluid connection 8. The cooling channel 9 runs around the wall of the recess 10.Because the heat sink is made of thermally conductive material, the wall of the recess 10 is cooled uniformly by the coolant, so that the locking element 4, which is in thermal contact with the recess 10, is also cooled uniformly.

[0036] To ensure maximum cooling of the fuse body 4, one side of the fuse body 4 of the high-voltage fuse facing the recess 10 is in full contact with the trough-shaped recess 10. To ensure such a full-surface fit of the fuse body in the trough-shaped recess 10, the contour of the recess 10 corresponds as closely as possible to the surface of the fuse body 4. In other words, the surface shape and dimensions of the recess 10 correspond to the surface shape and dimensions of the section of the fuse body 4 received in the recess 10.If the fuse body 4 is cylindrical, as in the present example, the contact surface of the recess 10 for the fuse body 4 is correspondingly cylindrical segment-shaped, with a curvature that matches the curvature of the fuse body to ensure the best possible surface contact. Deviations from these two shapes are possible, however, for example, to accommodate electrical contacts. This allows for particularly effective cooling of the high-voltage fuse.

[0037] For electrically connecting the passive residual current device 3 to an external circuit (not shown), the two connection areas 7 are provided to receive the connection contacts 6 of the fuse body 4. In the case shown here, the connection areas 7 consist of plates made of an electrically conductive material with a flat surface 12, into which a hole 11, in this case an elongated hole, has been milled. The connection contacts 6 of the fuse body 4 are brought into contact with the connection areas 7. An external power conductor, for example a copper busbar, is then placed on the surface 12 of the connection areas 7. A screw is then inserted through the elongated hole 11 and positively connects the connection contact 6, the connection area 7, and the external busbar.The busbar can optionally function simultaneously as a power supply to the vehicle's charging circuit and as a support structure for the cooling device 1. Several of the devices shown can be interconnected in a modular design to address different safety aspects of a charging circuit as flexibly as possible. Both the electrical and fluidic circuits, as well as the cooling circuits, can be configured as parallel or series connections.

[0038] The section through the cooling device indicated by the dashed line A corresponds to the section plane of the section explained below. Figure 3 agree.

[0039] Figure 3Figure 1 shows a cross-section equivalent to the section along line A through an embodiment of the invention, in which two cooling devices 1 for fluid cooling of the passive residual current device 3 are stacked on top of each other rotated 180° relative to each other. The device consists of two heat sinks 2, the recesses 10 of which face each other.

[0040] While the recess 10 of a single cooling device 1 has a trough-like shape open on one side, the stacking of the two cooling devices 1 creates an enclosed cavity for accommodating the passive residual current device 3. The two cooling channels 9 each run in a U-shape around the side wall of the recesses 10, so that the side walls, and thus the fuse body 4 that can be inserted into the recess 10, are cooled as uniformly as possible. To improve the thermal contact between the fuse body 4 and the two cooling elements 2, a thermal interface material 14 is located between the fuse body and the two cooling elements. In the embodiment shown here, the fluid connections 8 are all located on the right side of the cooling device, but are not shown due to the chosen section plane and the omission of hidden edges.

[0041] Due to the stacking of the two heat sinks 2, there are two contact areas 7 on each side of the fuse body 4 for electrical contact. It is possible to connect only one of the two contact areas 7 to an external busbar by means of a force-fit connection. The electrical contact of the connection contacts 6 can also only be made at this contact area. The heat sink 2 that is not connected to the busbar is, in this case, not part of the vehicle's electrical charging circuit, but serves solely to improve the cooling of the fuse body.

[0042] Although the invention has been described with reference to specific embodiments, it is apparent to a person skilled in the art that various modifications can be made and equivalents can be used as replacements without departing from the scope of the invention. Consequently, the invention is not intended to be limited to the disclosed embodiments, but rather to encompass all embodiments falling within the scope of the appended claims. Reference symbol list

[0043] 1 Cooling device 2 Heat sink 3 Passive residual current device, e.g., high-voltage fuse 4 Fuse body 5 Connecting conductor 6 Connection contact 7 Connection areas for receiving the connection contacts 8 Fluid connections 9 Cooling channel 10 Recess for receiving the fuse body 11 Hole for positive locking and electrical contact 12 Flat contact surface 13 Device for protecting a high-voltage circuit 14 Thermal conductor, e.g., thermal paste or thermal pad

Claims

1. Device (13), comprising: i) a passive fault-current protection device (3), preferably a high-voltage fuse, having a fuse body (4) with a connecting conductor (5) arranged therein, wherein the fuse body (4) has at each of its two ends a connection contact (6) which is connected to the connecting conductor (5); and ii) a cooling device (1) for fluid cooling of the passive fault-current protection device (3), wherein the cooling device (1) comprises: a) a cooling body (2), b) two connection regions (7) arranged on opposite sides of the cooling body (2) for receiving the connection contacts (6), c) two fluid connections (8), d) a cooling channel (9), which fluidically connects the two fluid connections (8) and runs in the interior of the cooling body (2), for a cooling fluid, e) wherein the cooling body (2) has, between the connection regions (7), a recess (10) for the sectional, areal accommodation of the fuse body (4), and the cooling channel (9) runs along at least one side wall of the recess (10), characterized in that the device is provided for the protection of a high-voltage circuit of a vehicle, preferably of a motor vehicle; and in that a surface shape and dimension of the recess (10) is configured to correspond in shape to a surface shape and dimension of the section of the fuse body (4) accommodated in the recess (10).

2. Device (13) according to claim 1, wherein a) the cooling channel (9) is led around the recess (10) and / or has a U-shaped course; and / or b) the fluid connections (8) are arranged at a same end region of the cooling body (2) with respect to the recess (10).

3. Device (13) according to claim 1 or 2, wherein the connection regions (7) each have a planar bearing surface (12) and a hole (11), preferably an elongated hole, for the force-fitting fastening and electrical contacting of the connection contacts (7).

4. Device (13) according to any of the preceding claims, wherein the cooling body (2) is made of a thermally conductive, electrically insulating material, preferably of plastic or a ceramic material.

5. Device (13) according to any of the preceding claims, wherein the section of the fuse body (4) accommodated in the recess (10) is at least partially in areal contact with a wall of the recess (10).

6. Device (13) according to any of the preceding claims, wherein a) the fuse body (4) is of cylindrical configuration and a bearing surface of the recess (10) for the fuse body (4) is configured in the form of a cylinder-jacket segment, or b) the fuse body (4) and a recess (10) for the fuse body (4) are of cuboid configuration.

7. Device (13) according to any of the preceding claims, which has two cooling devices (1) for fluid cooling of the passive fault-current protection device (3) according to any of the preceding claims, wherein the two cooling devices (1) are stacked one on top of the other, rotated by 180° relative to one another, such that the two recesses (10) of the two cooling devices (1) surround the fuse body (4) in the manner of a shell.

8. Device (13) according to claim 7, wherein the two fluid connections (8) are each arranged such that the two cooling devices (1) are connected and / or connectable fluidically in parallel or in series to an external cooling circuit via the fluid connections (8).

9. Device (13) according to any of the preceding claims, wherein, for improving the thermal contacting, a thermal paste (14) or a thermal pad (14) is provided between the fuse body (4) and the wall of the recess (10).

10. Device (13) according to any of the preceding claims, wherein the recess (10) for the sectional, areal accommodation of the fuse body (4) is a trough-like recess.

11. Device (13) according to any of the preceding claims, wherein the passive fault-current protection device (3) is a high-voltage fuse, wherein the connecting conductor (5) is a fusible conductor.

12. Motor vehicle, preferably utility vehicle, comprising a device (13) according to any of claims 1 to 11.

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