Electric device, method for producing same, and vehicle

Abstract

The invention relates to an electric device (1) which has a housing (2) with at least one dome (4) that protrudes into the housing (2); a heat-conducting element (10) which is arranged on the upper surface (6) of the dome (4); and a busbar (12) which is arranged on the heat-conducting element (10). Additionally, an electric insulating element (14) is arranged over the entire circumference of the dome (4), at least in an upper section of a lateral surface (8) of the dome (4), and so as to contact the heat-conducting element (10). The invention additionally relates to a method for producing the electric device and to a vehicle which has the electric device.

Description

[0001] Electrical device, method for producing the same and vehicle

[0002] Description

[0003] The present invention relates to an electrical device in which a busbar is arranged on a dome connected to a housing of the electrical device, and to a method for manufacturing the electrical device. The invention further relates to a vehicle having the electrical device.

[0004] In an electrical device, such as a converter, inverter, or rectifier, the installed components must be secured to one another to withstand environmental influences (shock, vibration, etc.). Thermal connection to dissipate generated heat and / or electrical insulation from the surrounding components must also be ensured. The use of a heat-conducting element, e.g., so-called thermal interface materials, for heat dissipation and electrical insulation is known. There are numerous suppliers of these heat-conducting elements, which differ in shape, material, and material properties.

[0005] Preferably, busbars are arranged on domes or columns in a housing of an electrical device. The heat-conducting element is arranged between an upper surface of a dome and a lower surface of the busbar to dissipate heat generated by the current flow in the busbar and to electrically insulate the dome from the busbar.

[0006] It is also conceivable for a dome to be designed with a large surface area so that several busbars can be arranged on it. The heat-conducting element then usually spreads out over the entire upper surface of the dome, while the busbars are arranged at a distance from each other to maintain creepage distances. This approach results in excessive material consumption for the heat-conducting element and a corresponding increase in costs. In high-voltage applications, requirements regarding clearance and creepage distances are not limited to a flat surface, but must also be met across a three-dimensional geometry. To counteract this problem, the domes are also equipped with heat-conducting elements on their side surfaces. This also requires a large amount of material and is expensive, and it also increases the weight of the electrical device.

[0007] It is therefore an object of the present invention to eliminate or at least mitigate the disadvantages of the prior art. In particular, it is an object of the present invention to provide an electrical device and a method for producing the same that enable reliable electrical insulation of a busbar from a housing of the electrical device while simultaneously meeting the requirements with regard to clearance and creepage distances. The requirements with regard to clearance and creepage distances are to be met for three-dimensional geometries and for a high-voltage application of the electrical device.

[0008] This object is achieved by the electrical device having the features according to claim 1, the vehicle having the features according to claim 7, and the method for producing the electrical device according to claim 8. Advantageous embodiments are the subject of the dependent claims.

[0009] An electrical device according to the invention has a housing with at least one dome or column. The dome projects from the housing, in particular into the housing, i.e. towards an inner side of the housing. The dome can be formed integrally with the housing. Alternatively, the dome can also be formed separately and connected to the housing via a permanent or detachable connection. In addition, the dome can have different shapes, e.g. cylindrical and cuboidal. The electrical device is preferably a converter which can convert electrical energy from one form, e.g. direct current, into another form, e.g. alternating current or three-phase current, preferably bidirectionally. The electrical device is particularly preferably usable in a vehicle, such as a hybrid vehicle or an electric vehicle. A heat-conducting element is arranged on an upper surface of the dome.The heat conducting element allows heat to be dissipated while ensuring electrical insulation.

[0010] A busbar or busbar is arranged on the heat-conducting element. Current can flow between two electrical components of the electrical device via the busbar. It is also conceivable for the busbar to have sections through which a current path does not pass. These sections can also be arranged on the heat-conducting element or on the dome. Particularly preferably, a busbar is assigned to a dome. The domes can then be arranged at a distance from one another according to the air gap requirements.

[0011] Furthermore, an electrical insulating element is arranged over an entire circumference of the dome at least in an upper portion of a side surface of the dome. In addition, the electrical insulating element is arranged over the entire circumference of the dome in contact with the heat-conducting element. The electrical insulating element also provides electrical insulation from the dome, i.e., the housing. However, compared to the heat-conducting element, the electrical insulating element can have a lower heat transfer coefficient. Consequently, a creepage distance extends from the heat-conducting element over the electrical insulating element and is thus longer compared to using the heat-conducting element alone.

[0012] The above-described structure of the electrical device ensures the requirements regarding air and creepage distances even for a three-dimensional geometry and for application in the high-voltage range

[0013] Preferably, the electrical insulating element can extend into an edge region of the upper surface. Consequently, the electrical insulating element is held by the extension onto the upper surface, and slipping down of the electrical insulating element, which is simply designed as a sleeve, for example, is prevented. Even more preferably, the heat-conducting element can be arranged at least partially above the electrical insulating element in the edge region. Of course, the heat-conducting element can extend into a region of the side surface of the dome and be arranged above the electrical insulating element. Consequently, the electrical insulating element is attached to the dome even better. Furthermore, a gap between the heat-conducting element and the electrical insulating element, through which electrical contact with the dome can be established, is reliably avoided.

[0014] The electrical insulation element can advantageously be formed by a heat-shrink tube. It should be noted that the heat-shrink tube has been previously heated on the mandrel. An initial shape of the heat-shrink tube is adapted to a shape of the mandrel so that the heat-shrink tube can be slipped over the mandrel. Compared to using a sleeve as an electrical insulation element, close contact with the mandrel can be achieved without the mandrel or the side surface of the mandrel having to be mechanically processed beforehand to meet precise geometric specifications. Consequently, good electrical insulation of the side surface of the mandrel can be achieved. In addition, heat-shrink tubing represents a low cost investment.

[0015] The heat-conducting element can advantageously be formed by thermal paste. The thermal paste can be a gap filler. This allows the busbar to be arranged floatingly on the dome, allowing externally applied mechanical stress and structural tolerances to be easily compensated.

[0016] The electrical device can be designed in particular for a high-voltage application. The electrical device is preferably operated at a nominal voltage of 800 V, with the clearance and creepage distances being designed according to this voltage. The use of the electrical device is made possible by the interaction of the heat-conducting element and the electrical insulating element. Different designs are of course possible for correspondingly higher or lower voltages. The height of the electrical insulating element for high-voltage applications is preferably designed to at least the value according to DIN EN IEC 60664-1. Depending on the industry and project, increased requirements for the creepage distance are also common, for example doubling the height. The dome must then also be set to a height that corresponds at least to the height of the insulating element.

[0017] A vehicle according to the invention comprises the electrical device according to the invention. Accordingly, the vehicle can be used for high-voltage applications.

[0018] A method according to the invention for producing an electrical device initially comprises a step of providing a housing with at least one dome. The dome protrudes from the housing, in particular into the housing, i.e. towards an inner side of the housing. The dome can be formed integrally with the housing. Alternatively, the dome can also be formed separately and connected to the housing via a permanent or detachable connection. In addition, the dome can have different shapes, e.g. cylindrical and cuboidal. The electrical device is preferably a converter which can convert electrical energy from one form, e.g. direct current, into another form, e.g. alternating current or three-phase current, preferably bidirectionally. The electrical device is particularly preferably usable in a vehicle, such as a hybrid vehicle or an electric vehicle.

[0019] This is followed by a step of arranging an electrical insulating element over the entire circumference of the dome, at least in an upper portion of a side surface of the dome. The electrical insulating element provides electrical insulation with respect to the dome, i.e., the housing.

[0020] Next, a step is performed to apply a heat-conducting element to an upper surface of the dome such that the heat-conducting element and the electrical insulation element are in contact over the entire circumference of the dome. The heat-conducting element enables heat dissipation while simultaneously ensuring electrical insulation. However, compared to the electrical insulation element, the heat-conducting element can have a higher heat transfer coefficient. Consequently, heat can be dissipated more effectively via the heat-conducting element than via the electrical insulation element.

[0021] The final step involves arranging a busbar on the heat-conducting element. The busbar allows current to flow between two electrical components of the electrical device. Particularly preferably, a busbar is assigned to each dome. The domes can then be arranged with sufficient spacing from each other, depending on the air gap requirements.

[0022] Accordingly, in the electrical device obtained by the method, a creepage distance extends from the heat-conducting element across the electrical insulating element and is thus longer than when the heat-conducting element is used alone. The above-described structure of the electrical device obtained by the method ensures that the requirements regarding air and creepage distances are met even for a three-dimensional geometry and for application of the electrical device in the high-voltage range.

[0023] Advantageously, the step of arranging the electrical insulating element comprises a step of placing a heat-shrink tube over the mandrel and a step of heating the heat-shrink tube. Consequently, the electrical insulating layer is easily formed by the heat-shrink tube. An initial shape of the heat-shrink tube is adapted to a shape of the mandrel so that the heat-shrink tube can be slipped over the mandrel. Compared to using a sleeve as an electrical insulating element, close contact with the mandrel can be achieved without the mandrel or the side surface of the mandrel having to be mechanically processed beforehand to meet precise geometric specifications. Consequently, good electrical insulation of the side surface of the mandrel can be achieved. Furthermore, heat-shrink tubing represents a low cost investment.

[0024] Particularly preferably, the heat-shrink tubing can extend up to 1 mm beyond the mandrel. This allows the protruding portion of the heat-shrink tubing to rest on an edge area of ​​the mandrel's upper surface. Consequently, good contact is achieved between the heat-conducting element and the electrical insulation element.

[0025] Furthermore, the step of applying the thermally conductive element can include a step of applying thermally conductive paste. The thermally conductive paste can, in particular, be a gap filler. In this way, the busbar can be connected to the dome in a floating or elastic manner, allowing externally applied mechanical stress and structural tolerances to be easily compensated.

[0026] Short description of the characters

[0027] An embodiment of the present invention will be described below with reference to the figures. In the figures, the same reference numerals are assigned to the same elements. They show:

[0028] Fig. 1 is a sectional view of an electrical device according to an embodiment of the present invention; and

[0029] Fig. 2 sectional views of the electrical device in the individual steps of a method for manufacturing the electrical device according to an embodiment of the present invention.

[0030] Fig. 1 shows a sectional view of an electrical device 1 according to an embodiment of the present invention. The electrical device 1 has a housing 2, from which at least one dome 4 or column protrudes. The dome 4 can be cylindrical or cuboid-shaped. The dome 4 has an upper surface 6 and a side surface 8. In the example shown, the housing 2 has two domes 4. However, the invention is not limited to this number of domes, and one dome, three domes, or more than three domes can also be provided. In the example shown, the domes 4 are formed integrally with the housing 2. The housing 2 is, for example, an aluminum die-cast housing. However, the domes 4 can also be formed separately and be detachably or permanently connected to the housing 2. Arranged on the upper surface 6 of the dome 4 is a heat-conducting element 10, which in the present embodiment is designed as a gap filler, which is a type of thermal paste.A busbar 12 or busbar for conducting current in the electrical device 1 from one electrical component to another is arranged on the heat-conducting element 10. Due to the pasty consistency of the heat-conducting element 10, the busbar 12 is mounted in a floating manner. Consequently, external mechanical loads and structural deviations, e.g., between the components connected to the busbar 12, can be compensated.

[0031] Furthermore, an electrical insulating element 14, which in the present embodiment is designed as a shrink tube, is arranged on the side surface 8 of the dome 4. Particularly preferably, the electrical insulating element 14, as shown in Fig. 1, extends into an edge region 16 of the upper surface 6 of the dome 4. The heat-conducting element 10 can then be arranged at least partially over the electrical insulating element 14 in the edge region 16. Consequently, reliable electrical insulation is achieved at a transition between the heat-conducting element 10 and the electrical insulating element 14. Furthermore, a creepage distance K from the busbar 12 to the housing 2 is extended by the arrangement of the electrical insulating element 14.

[0032] As already mentioned, several domes 4 can also protrude from the housing 2 of the electrical device 1. Each dome 4 is then assigned its own busbar 12. To comply with the air gap L requirements, the domes are arranged at a correspondingly large distance from each other.

[0033] Accordingly, the electrical device 1 according to the present embodiment can meet the requirements regarding clearance and creepage distances L, K in a simple and cost-effective manner. For example, the height of the electrical insulating element can be set to at least 4.9 mm, so that the electrical device 1 is suitable for a high-voltage application at a rated voltage of 800 V. In particular, the electrical device 1 can be used in a vehicle, such as a hybrid vehicle or an electric vehicle. The electrical device 1 can, for example, be an inverter for an electric motor of the electric vehicle.

[0034] A method for manufacturing the electrical device 1 will be described below with reference to Fig. 2.

[0035] In the first step a), the housing 2, from which a dome 4 protrudes in the example shown, is first prepared. The dome 4 has an upper surface 6 and a side surface 8.

[0036] In step b), a shrink tube is placed over the dome 4 as the electrical insulating element 14. As indicated by the dashed line, the shrink tube protrudes between 0.5 and 1 mm beyond the dome 4.

[0037] In the subsequent step c), the heat-shrink tubing serving as the electrical insulating element 14 is heated, e.g., by supplying warm air. This causes the heat-shrink tubing to conform to the dome 4. Because the heat-shrink tubing extends beyond the dome 4, it also extends into an edge region 6 of the upper surface 6 of the dome 4.

[0038] In step d), gap filler is applied in a metered manner to the upper surface 6 of the dome 4 as the heat-conducting element 10. The gap filler is applied in the edge region 16 at least partially over the electrical insulating element 14.

[0039] In the final step e), the busbar 12 is then arranged on the heat-conducting element 10. Consequently, the busbar 12 is connected to the dome 4 in a floating or elastic manner.

[0040] It should be noted that the gap filler can also be applied in the edge region 16 above the electrical insulating element 14 by pressing the busbar 12 onto the gap filler and is not limited to the application in step d). Furthermore, the gap filler, i.e., the heat-conducting element 10, can also extend into a region of the side surface 8 of the dome 4. The electrical device 1 and the method for producing the electrical device 1 thus make it possible to meet the requirements regarding clearance and creepage distances K, L in a simple and cost-effective manner.

[0041] List of reference symbols

[0042] 1 electrical device

[0043] 2 housings

[0044] 4 Cathedral

[0045] 6 upper surface

[0046] 8 side surface

[0047] 10 Heat conducting element

[0048] 12 Busbar

[0049] 14 electrical insulating element

[0050] 16 Marginal area

[0051] L Air gap

[0052] K Creepage distance

Claims

Claims 1. Electrical device (1) comprising: a housing (2) with at least one dome (4) protruding from the housing (2); a heat-conducting element (10) arranged on an upper surface (6) of the dome (4); and a busbar (12) arranged on the heat-conducting element (10), characterized by an electrical insulating element (14) arranged over an entire circumference of the dome (4), at least in an upper portion of a side surface (8) of the dome (4) and in contact with the heat-conducting element (10).

2. Electrical device (1) according to claim 1, wherein the electrical insulating element (14) extends into an edge region (16) of the upper surface (6).

3. Electrical device (1) according to claim 2, wherein the heat conducting element (10) is arranged in the edge region (16) at least partially above the electrical insulating element (14).

4. Electrical device (1) according to one of claims 1 to 3, wherein the electrical insulating element (14) is formed by a shrink tube.

5. Electrical device (1) according to one of claims 1 to 4, wherein the heat-conducting element (10) is formed by heat-conducting paste, in particular by gap filler.

6. Electrical device (1) according to one of claims 1 to 5, wherein the electrical device (1) is designed for a high-voltage application, in particular for a voltage of 800 V.

7. Vehicle comprising an electrical device (1) according to one of the preceding claims 1 to 6.

8. A method for manufacturing an electrical device (1 ), comprising the following steps: Providing a housing (2) with at least one dome (4) projecting into the housing (1); Arranging an electrical insulating element (14) which is arranged over an entire circumference of the dome (4) at least in an upper section of a side surface (8) of the dome (8); Applying a heat-conducting element (10) to an upper surface (6) of the dome (4) such that the heat-conducting element (10) and the electrical insulating element (14) are in contact over the entire circumference of the dome (4); Arranging a busbar (12) on the heat conducting element (10).

9. The method according to claim 8, wherein the step of arranging the electrical insulating element (14) comprises: Placing a shrink tube, which in particular protrudes up to 1 mm over the dome, over the dome (4), and Heating the shrink tubing.

10. The method according to claim 8 or 9, wherein the step of applying the heat conducting element (10) comprises: Applying thermal paste, especially gap filler.

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