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] Cooling device for fluid cooling of a passive residual current device

[0002] Description

[0003] The invention relates to a cooling device for fluid cooling of a passive residual current device, preferably a high-voltage fuse. The invention further comprises a device for protecting a high-voltage circuit of a vehicle, comprising such a cooling device and a passive residual current device.

[0004] The advancement of e-mobility, particularly in the commercial vehicle sector, requires ever-increasing charging power for the rapid charging of high-voltage vehicle batteries. Passive residual current devices, usually in the form of high-voltage fuses, are used to protect the charging circuit. Passive residual current devices such as high-voltage fuses are used in the vehicle's charging path in combination with high-voltage contactors to electrically protect the charging path between the charging station and the electric vehicle. The high-voltage fuses must be able to safely carry high charging currents while still ensuring rapid disconnection of the fault current in the event of a short circuit. These requirements (high current-carrying capacity on the one hand and rapid disconnection of the fault current on the other) are physically in competition with each other and can only be implemented at the expense of the other.For example, the two charging standards ISO17409 and ISO5474-3 specify limits for the maximum permissible fault current for the charging circuit.

[0005] Practical approaches are known in which the passive residual current device is cooled passively, primarily via the copper bars connected for electrical contact. The disadvantage of this is that the possible continuous charging currents are limited, as thermal overload of the fuse can occur during normal charging. Furthermore, it is not possible to conduct charging currents greater than 1,000 A through the high-voltage fuse. Simply increasing the size of the high-voltage fuse would violate the specified limit values ​​of the ISO standards.

[0006] Special actively fluid-cooled circuit arrangements with a fuse are also known from the prior art. For example, the published patent application WO 2018 / 069141 A1 describes a circuit arrangement with a fuse in which the fuse is designed in the form of a layer arrangement on a heat sink. The layer arrangement is guided over a bridge element formed by two material recesses in the heat sink. To provide the melting range of the layer arrangement, a heat buildup is deliberately provoked in the area of ​​the bridge element. The melting point, i.e. the current strength 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 layer arrangement.The disadvantage of this arrangement is that for each application for which a residual current device is required, a new, complex dimensioning of the bridge element and the layer arrangement must be carried out, so that only special versions of fuses can be used.

[0007] It is therefore an object of the invention to provide a technology that avoids the disadvantages of existing solutions, or at least mitigates these disadvantages. This object is achieved by the cooling device having 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 is provided. The passive residual current device comprises a fuse body with a connecting conductor arranged therein. The fuse body has a connection contact at each end, which is connected to the connecting conductor. In a preferred embodiment, the passive residual current device is designed as a high-voltage fuse. In this case, the connecting conductor is a fusible element.

[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 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 flat, section-by-section accommodation of the fuse body. The cooling channel runs along at least one side wall of the recess. A recess for the flat, section-by-section accommodation of the fuse body means that the fuse body is and / or can be placed and / or inserted into the recess and rests there flatly with at least a section of the fuse body, i.e., forms a flat contact within the receptacle with the wall of the heat sink. For this purpose, the recess is preferably trough-shaped (trough-like).

[0011] The cooling device described enables advantageous active fluid cooling of a passive residual current device. This makes it possible to use a smaller high-voltage fuse with fast tripping characteristics that complies with the limits of ISO standards and, thanks to the active fluid cooling, is not thermally overloaded or incorrectly tripped at high DC charging currents greater than 1,000 A. The cooling device allows the cooling fluid to be advantageously guided past the passive residual current device through the cooling channel, while at the same time, effective thermal coupling is achieved via the surface contact of the heat sink with the passive residual current device. This enables particularly effective fluid cooling of the passive residual current device.Furthermore, this cooling device makes it possible to cool standardized, commercially available high-voltage fuses, thus achieving cost-effective and economical use.

[0012] The fluid connections allow the heat sink to be connected to a coolant circuit, allowing coolant to flow into the cooling channel through one of the fluid connections on the inlet side and exit through the other on the outlet side. Cooling the fuse body in this way can increase the maximum current flow through the charging circuit. For example, cooling increases the continuous current that the fuse must 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; in particular, good cooling of the side wall of the recess can be achieved. Alternatively or additionally, it is possible for the fluid connections to be arranged at the same end of the heat sink with respect to the recess. This enables the longest possible cooling path and also simple connection of the cooling device to a coolant circuit, whereby the length of the required connecting coolant lines can be kept as short as possible. Preferably, the connection areas of the cooling device can each have a flat support surface and / or a hole, preferably an elongated hole, for the force-fitting fastening and electrical contacting of the connection contacts.This is particularly advantageous for accommodating connection contacts in the form of busbars. The flat contact surfaces of the connection contacts serve as a support surface for the busbars. A screw can be inserted through the hole, allowing the busbar to be securely fastened to the heat sink with a force fit. By selecting suitable, electrically conductive materials, the electrical contact is established simultaneously. The use of an elongated hole instead of a circular hole allows for greater flexibility during installation.

[0014] The heat sink is preferably 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 even 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 a further aspect of 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 as the "device." The device comprises a passive residual current device, preferably a high-voltage fuse, and a cooling device for fluid cooling the passive residual current device, as described above. This means that the passive residual current device has a fuse body with a connecting conductor arranged therein, wherein the fuse body has a connection contact at each end, which is connected to the connecting conductor.

[0016] In a preferred embodiment, the portion of the fuse body accommodated in the recess is at least partially in surface contact with a wall of the recess. The surface contact of the fuse body with the wall of the recess enables effective and uniform cooling of the fuse body, as already explained above.

[0017] Preferably, the surface shape and dimensions of the recess are designed to correspond to the surface shape and dimensions of the portion of the fuse body accommodated in the recess. Accordingly, the largest possible surface contact between the heat sink and the fuse body can be achieved.

[0018] It was stated above that the recess can be designed in a trough-like manner. An advantageous embodiment of this provides that the trough-like recess is shaped such that a fuse body can be inserted at least in section. The contour of the recess can be shaped such that it follows the outer contour of the fuse body or is adapted to it, so that the largest possible contact area exists between the outer surface of the fuse body and the side wall of the recess. The fuse body does not have to be completely recessed into the heat sink. It is also possible for the lower part of the fuse body to be inserted into the heat sink and the other part of the fuse body to protrude above the heat sink. In this case, the contour of the side wall of the recess follows the part of the fuse body 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 roundings or flattenings, as well as additional recesses for routing contacts, can be provided in the area of ​​the heat sink recess.

[0019] A high-voltage fuse known from practical use can be used as the high-voltage fuse. Commercially available versions include versions with a cylindrical fuse body (high-voltage round body fuses) and versions with a cuboid fuse body (high-voltage square body fuses).

[0020] Accordingly, with regard to these common designs of high-voltage fuses, the fuse body can be designed cylindrically – purely as an example. The support surface of the recess for the fuse body is then designed in the shape of a cylindrical shell segment. A cylindrical shell segment means a circular segment that has been extruded linearly along the normal vector of the circular segment surface. Alternatively, the fuse body and a recess for the fuse body can each be cuboid-shaped. The edges of the cuboids can be rounded. The edge lengths of the cuboid-shaped fuse body and the cuboid-shaped recess do not have to be identical. The advantage of these designs is the possibility of using commercially available passive residual current devices that have cylindrical or cuboid-shaped fuse bodies.The corresponding cylinder jacket segment-shaped support of the recess or the cuboid-shaped recess enable efficient and uniform cooling of these commercially available fuse bodies.

[0021] However, it is emphasized that the design of the recess or its support surface is not limited to these two variants and can accordingly have a different shape, in particular in the case that a high-voltage fuse is to be cooled which has a fuse body shape 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. The two cooling devices, in particular their heat sinks, are stacked on top of one another, rotated 180° to each other, so that the two recesses of the two cooling devices surround the fuse body in a shell-like manner. In this way, the fuse body can be cooled evenly from all sides, so that heat build-up does not occur at any point within the fuse body. Cooling can be further improved accordingly. Furthermore, a modular approach is implemented, since the device is constructed in a modular manner from two, preferably structurally identical, cooling devices.

[0023] The two fluid connections of the stacked cooling devices can each be arranged such that the two cooling devices are and / or can be connected to an external cooling circuit via the fluid connections, either in parallel or in series. If the cooling devices are to be connected to an external cooling circuit in parallel, then each cooling device has two separate fluid connections to the external cooling circuit. If, however, the two cooling devices are to be connected to an external cooling circuit in series, then the two stacked cooling channels are fluidly connected via two of the fluid connections, while one of the remaining two fluid connections serves as the input connection and the other as the output connection with respect to the external cooling circuit.

[0024] The option of connecting the cooling channels in series or in parallel allows for the design of the external cooling circuit to be taken into account. Factors such as the type of lines, the available space, or the temperature of the coolant can all play a role. For example, if there is very little space for routing lines, it may be advisable to choose a fluidic series connection with a total of two fluid connections on the outer sides, thus requiring only two external fluid lines. However, if the temperature stability of the fuse body is particularly critical, a fluidic parallel connection of the two heat sinks could be chosen.

[0025] Furthermore, in a further 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 side wall of the recess does not perfectly match the outer surface of the fuse body, for example, due to manufacturing or different surface structures, the thermal paste or thermal pad can optionally compensate for the unevenness, ensuring the greatest possible thermal contact between the heat sink and the fuse body.

[0026] According to a further aspect of the invention, a motor vehicle is provided, comprising a cooling device according to one of the previously described embodiments. The motor vehicle is preferably a commercial vehicle. In other words, the vehicle can be a vehicle which, due to its design and equipment, is designed for transporting people, for transporting goods, or for towing trailers. Preferably, the vehicle is a tractor unit, i.e., a vehicle for towing a semitrailer or trailer. Particularly preferably, the vehicle is a tractor unit without a coupled semitrailer.

[0027] The previously described preferred embodiments and features of the invention can be combined with one another as desired. Further details and advantages of the invention are described below with reference to the accompanying drawings.

[0028] It shows

[0029] Figure 1 is a schematic perspective view of a device for protecting a high-voltage circuit of a vehicle according to one embodiment;

[0030] Figure 2 is a schematic representation of a high-voltage fuse; and

[0031] Figure 3 is a schematic representation of an embodiment in which two heat sinks are stacked on top of each other, rotated 180° to each other. Figure 1 is a schematic perspective representation of a device 13 for protecting a high-voltage circuit of a vehicle, in particular a motor vehicle.

[0032] The device 13 comprises a cooling device 1 for fluid cooling of a passive residual current device, preferably a high-voltage fuse.

[0033] 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 for a cooling fluid which fluidically connects the two fluid connections 8 and runs inside the heat sink 2.

[0034] The cooling channel 9 has a U-shaped course 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-wise, flat reception of the high-voltage fuse, in particular for the flat reception of the fuse body 4 of the high-voltage fuse, which will be explained below.

[0035] Figure 1 only partially shows the fuse body 4 of the high-voltage fuse. The high-voltage fuse 3 is shown schematically in Figure 2. As shown in Figure 2, the high-voltage fuse 3 comprises a fuse body 4 with a connecting conductor 5 extending therein, also referred to as a fusible element, which connects the two ends of the fuse body 4 to each other. The fuse body 4 has a connection contact 6 at each end, which is electrically connected to the connecting conductor 5.

[0036] Should the current flow in the circuit become too great, e.g. 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 is made of an electrically insulating material so that the arc created when the circuit is interrupted is absorbed by the fuse body, thus protecting the rest of the circuit from further damage. The fuse bodies are often additionally filled with a granular material such as quartz sand in order to extinguish the arc as quickly and reliably as possible. Such high-voltage fuses 3 are known per se from the prior art and are often designed with cylindrical (as shown in Figure 2) or cuboid-shaped fuse bodies 4.

[0037] Referring again to Figure 1, the 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 provided 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 through one of the fluid connections 8 into the cooling channel 9, cools the material of the heat sink 2 there, and then flows back through the other fluid connection 8 into the external cooling circuit. 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 evenly cooled by the coolant, so that the fuse body 4, which is in thermal contact with the recess 10, is also evenly cooled.

[0038] In order to ensure the greatest possible cooling of the fuse body 4, a side of the fuse body 4 of the high-voltage fuse facing the recess 10 is in surface contact with the trough-like recess 10. In order to ensure such a surface reception of the fuse body in the trough-like recess 10, the contour of the recess 10 corresponds as closely as possible to the outer surface of the fuse body 4. In other words, a surface shape and dimension of the recess 10 is designed to correspond to a surface shape and dimension 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 support surface of the recess 10 for the fuse body 4 is designed in the shape of a corresponding cylindrical shell segment, with a curvature that corresponds to the curvature of the fuse body to enable the best possible surface contact. However, deviations between the two shapes are possible, for example, for the installation of electrical contacts. This allows for particularly effective cooling of the high-voltage fuse.

[0039] For electrically connecting the passive residual current device 3 to an external circuit (not shown), the two connection areas 7 are provided to accommodate the connection contacts 6 of the fuse body 4. In the case shown here, the connection areas 7 consist of small plates made of an electrically conductive material with a flat surface 12, into each of which a hole 11, in this case an elongated hole, has been recessed. The connection contacts 6 of the fuse body 4 are brought into contact with the connection areas 7. An external power line, 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 line to the vehicle's charging circuit and as a support structure for the cooling device 1. Several of the devices shown can be interconnected within a modular design to address different safety aspects of a charging circuit as flexibly as possible. Both the electrical and fluidic power or cooling circuits can be implemented as parallel or series circuits.

[0040] The section through the cooling device indicated by the dashed line A corresponds to the section plane of Figure 3 explained below.

[0041] Figure 3 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, whose recesses 10 face each other.

[0042] While the recess 10 in a single cooling device 1 has a trough-like shape that is 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 walls 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 evenly as possible. To improve the thermal contact between the fuse body 4 and the two heat sinks 2, a heat conducting agent 14 is located between the fuse body and the two heat sinks. In the embodiment shown here, the fluid connections 8 are all located on the right-hand side of the cooling device, but are not shown due to the selected sectional plane and the omission of hidden edges.By stacking the two heat sinks 2, two contact areas 7 for electrical contact are located on each side of the fuse body 4. It is possible to force-connect only one of the two contact areas 7 to an external busbar. The electrical contacting of the connection contacts 6 can also be made exclusively at this contact area.

[0043] Heat sink 2, which is not connected to the busbar, is in this case not part of the vehicle's electrical charging circuit, but serves exclusively to improve the cooling of the fuse body.

[0044] Although the invention has been described with reference to specific embodiments, it will be apparent to one skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention. Consequently, the invention is not intended to be limited to the disclosed embodiments, but is intended to include all embodiments falling within the scope of the appended claims. In particular, the invention also claims protection for the subject matter and features of the dependent claims, independent of the referenced claims.

[0045] List of reference symbols

[0046] 1 cooling device

[0047] 2 heat sinks

[0048] 3 Passive residual current device, e.g. high-voltage fuse 4 Fuse body

[0049] 5 connecting conductors

[0050] 6 connection contact

[0051] 7 connection areas for the connection contacts

[0052] 8 Fluid connections 9 Cooling channel

[0053] 10 Recess for receiving the fuse body

[0054] 11 Hole for force-locking fastening and electrical contact

[0055] 12 Flat support surface

[0056] 13 Device for protecting a high-voltage circuit 14 Thermal conductive material, e.g. thermal paste or thermal pad

Claims

Patent claims 1. Cooling device (1) for fluid cooling of a passive residual current device (3), preferably a high-voltage fuse, wherein the passive residual current device (3) has a fuse body (4) with a connecting conductor (5) arranged therein, wherein the fuse body (4) has a connection contact (6) at each end which is connected to the connecting conductor (5), wherein the cooling device (1) comprises: a) a heat sink (2), b) two connection areas (7) arranged on opposite sides of the heat sink (2) for receiving the connection contacts (6), c) two fluid connections (8), d) a cooling channel (9) extending inside the heat sink (2) and fluidically connecting the two fluid connections (8), for a cooling fluid, e) wherein the heat sink (2) has a recess (10), preferably a trough-like recess, between the connection areas (7) for section-wise,has a flat receiving area for the locking element (4) and the cooling channel (9) runs along at least one side wall of the recess (10).

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

3. Cooling device (1) according to claim 1 or 2, wherein the connection areas (7) each have a flat contact surface (12) and a hole (11), preferably an elongated hole, for force-fit fastening and electrical contacting of the connection contacts (7).

4. Cooling device (1) according to one of the preceding claims, wherein the heat sink (2) is made of a thermally conductive, electrically insulating material, preferably plastic or a ceramic material. Device (13) for protecting a high-voltage circuit of a vehicle, in particular a motor vehicle, comprising a) a passive residual current device (3), preferably a high-voltage fuse, comprising a fuse body (4) with a connecting conductor (5) arranged therein, wherein the fuse body (4) has a connection contact (6) at each end which is in contact with the connecting conductor (5); and b) a cooling device (1) for fluid cooling of the passive residual current device (3) according to any one of claims 1 to 4.Device according to claim 5, wherein a) the section of the locking element (4) received in the recess (10) is at least partially in planar contact with a wall of the recess (10); and / or b) a surface shape and dimension of the recess (10) is designed to correspond to a surface shape and dimension of the section of the locking element (4) received in the recess (10). Device according to claim 5 or 6, wherein a) the locking element (4) is cylindrical and a bearing surface of the recess (10) for the locking element (4) is cylindrical segment-shaped, or b) the locking element (4) and a recess (10) for the locking element (4) are cuboid-shaped.Device (13) according to any one of claims 5 to 7, comprising two cooling devices (1) for fluid cooling of the passive residual current device (3) according to any one of claims 1 to 4, wherein the two cooling devices (1) are stacked on top of each other rotated by 180° relative to each other, so that the two recesses (10) of the two cooling devices (1) surround the fuse body (4) in a shell-like manner. Device (13) according to claim 8, wherein the two fluid connections (8) are each arranged such that the two cooling devices (1) are fluidically connected and / or connectable via the fluid connections (8) in parallel or in series to an external cooling circuit. Device (13) according to any one of claims 5 to 9, wherein a thermal paste (14) or a thermal pad (14) is provided between the fuse body (4) and the wall of the recess (10) to improve thermal contact. Device (13) according to any one of claims 5 to 10, wherein the passive residual current protective device (3) is a high-voltage fuse, wherein the connecting conductor (5) is a fusible link. Motor vehicle, preferably commercial vehicle, comprising a cooling device (1) according to any one of claims 1 to 4 or a device (13) according to any one of claims 5 to 11.

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