DE102023111179A1 - High-voltage terminal for a stator, stator and method for producing a high-voltage terminal - Google Patents

Abstract

The invention relates to a high-voltage terminal (1) for a stator, comprising at least three conductor phases (3, 4, 5) for electrically connecting the high-voltage terminal (1) to power electronics (6) for energizing a winding of the stator, wherein each of the at least three conductor phases (3, 4, 5) is formed from at least two essentially parallel rail strands (7a, 7b, 8a, 8b, 9a, 9b) which are connected in an electrically insulating manner from one another and at a distance from one another via a plurality of spacer elements (10), wherein the spacer elements (10) each have a first plate element (11), a second plate element (12) and at least one third plate element (13), which are arranged at a distance from one another on a shaft (14) of the spacer element (10) and each protrude from the shaft (14) in the radial direction.

Description

The present invention relates to a high-voltage terminal for a stator, comprising at least three conductor phases for electrically connecting the high-voltage terminal to power electronics for supplying current to a winding of the stator, wherein each of the at least three conductor phases is formed from at least two essentially parallel rail strands which are connected in an electrically insulating manner from one another and spaced apart from one another via a plurality of spacer elements. The invention further relates to a stator and a method for producing a high-voltage terminal.

Electric motors are increasingly being used to power motor vehicles in order to create alternatives to combustion engines that require fossil fuels. Considerable efforts have already been made to improve the everyday suitability of electric drives and to also offer users the driving comfort they are used to.

A detailed description of an electric drive can be found in an article by Journal ATZ 63rd year, 05/20 6, pages 360-365 by Erik Schneider, Frank Fickl, Bernd Cebulski and Jens Liebold with the title: Highly integrated and flexible electric drive unit for electric vehicles. This article describes a drive unit for an axle of a vehicle, which includes an electric motor arranged concentrically to a bevel gear differential. Such drive units are also referred to as electric axles.

In addition to purely electrically operated drive trains, hybrid drive trains are also known. Such drive trains in a hybrid vehicle usually comprise a combination of an internal combustion engine and an electric motor, and enable - for example in urban areas - purely electric operation while at the same time providing sufficient range and availability, especially for cross-country journeys. In certain operating situations, it is also possible to drive the vehicle simultaneously using the internal combustion engine and the electric motor.

For the development of electrical machines, in particular electrical machines for the above-mentioned hybrid or fully electric motor vehicles or also for wheel hub drives, basically different winding technologies for a stator of an electrical machine are known.

Permanently excited synchronous machines (PSM) are often used in the application areas listed above. Such a permanent-excited synchronous machine usually has a stator to be energized and a permanently excited rotor. The stator includes a wire winding, a stator carrier, an interconnection ring and a high-voltage terminal for the power electronics.

Electrical machines with distributed winding or wave winding usually have a connection area in which different conductors of the winding are connected to one another. This connection is also called a bridge, which is usually responsible for reversing the direction of the current flow. The connection can also contain a so-called star point. At this point, all conductors and currents of the different phases flow together according to a star connection. The electrical machine also has a high-voltage terminal as a component. This component is responsible for supplying the electrical machine with power via the power electronics.

Electrical machines that have a stator with a hollow cylindrical stator, i.e. are designed as an internal rotor machine, and that are configured for use as a traction drive for a motor vehicle, often have a stator winding with a rectangular cross-section in order to achieve a high power density. In electrical machines that are intended for driving motor vehicles, the stator windings are therefore typically designed as I-pin or hairpin windings. In this case, for example, essentially I- or U-shaped wire segments are introduced into the stator slots from one end of the stator and then formed on an opposite end of the stator and connected, for example, by welding.

Such wire segments, which are also referred to as busbars, are either punched out of copper sheets or partially formed from rectangular wire. In order to be able to electrically connect the busbars of the stator winding with the busbars of the power electronics, which are also referred to as inverters, a high-voltage terminal is usually positioned in the current flow between the power electronics and one of the winding heads of the stator winding.

High-voltage terminals are now known from the state of the art. For example, the DE 10 2019 111 825 A1 a stator for an electrical machine with such a high-voltage terminal.

Due to the current design of an electric motor in an electric drive train of a motor vehicle, e.g. as a hybrid module, as a so-called e-axle or as a wheel hub motor, the high-voltage terminal is usually equipped with several copper rails. In order to save installation space, the copper tracks must be brought as close to each other as possible. However, this can make compliance with the necessary clearance and creepage distances critical. It is therefore generally known to determine the position and distance between the copper rails using a corresponding plastic overmolding, which can generate an extended creepage distance.

Despite this fixing of the busbars by means of a plastic overmold, unwanted voltage flashovers can still occur between the copper busbars of the circuit if the necessary minimum distance or the minimum creepage distances cannot be reliably maintained due to the plastic overmold due to manufacturing reasons. For example, faulty connection of the pre-molded plastic with the final overmolded plastic can lead to voltage flashovers between the electrical copper connections of the high-voltage terminal.

It is therefore the object of the invention to provide a high-voltage terminal for a stator which avoids or at least mitigates the problems known from the prior art and provides a high-voltage terminal for a stator which has a high degree of protection against voltage surges. It is also the object of the invention to realize a correspondingly improved stator and an optimized method for producing a high-voltage terminal.

This object is achieved by a high-voltage terminal for a stator, comprising at least three conductor phases for electrically connecting the high-voltage terminal to power electronics for energizing a winding of the stator, wherein each of the at least three conductor phases is formed from at least two essentially parallel rail strands which are connected via a plurality of spacer elements in an electrically insulating manner from one another and spaced apart from one another, wherein the spacer elements each have a first plate element, a second plate element and at least one third plate element, which are arranged spaced apart from one another on a shaft of the spacer element and each protrude from the shaft in the radial direction.

In a high-voltage terminal, the creepage distance is usually the critical current path in the event of an unwanted voltage flashover, since the current can creep along the geometry of the insulating bodies or spacer elements. The creepage distance between the busbars, which are stacked axially, for example, is automatically ensured by the geometry of the spacer elements with their at least three plate elements, since these plate elements can provide a comparatively long creepage distance in relation to the longitudinal extent of the spacer element. This geometry has proven to be highly effective in preventing a current or voltage flashover between two busbar strands within the high-voltage terminal.

The spacer elements make it possible for the rail tracks to maintain the required clearance and creepage distances and for the high-voltage terminal to be attached to a housing or encapsulated in plastic.

Advantageously, pre-mold coating can be dispensed with, as the spacer elements are used with a wave-shaped outer structure defined by the plate elements, which, for example, ensure that the distance or the necessary creepage distances can be maintained even if there are potential cavities or defects in the surrounding, injection-molded plastic housing, even though the copper rails in the molded plastic are only a short distance apart. This means that the creepage distances are maintained regardless of possible material inhomogeneities in the surrounding plastic. Avoiding the previously common pre-mold coating of the high-voltage terminal can also help to make the high-voltage terminal safer for series production.

The spacer element is preferably designed as an electrical insulator. In this context, a spacer element is preferably made of an electrically non-conductive material, for example a plastic and/or a ceramic. A spacer element can also have an electrically non-conductive coating.

It is further preferred that the first plate element and/or the second plate element and/or the third plate element are formed integrally, in particular monolithically, with the shaft.

A plate element is preferably formed as a circular disk. In principle, it would also be conceivable to provide other shapes for a plate element. A plate element is particularly preferably arranged coaxially to the shaft. This means that the creepage distance in the axial direction is essentially the same over the circumference of the spacer element. The circular disk-shaped plate elements can particularly preferably also have different diameters, which can help to extend the creepage distances in the axial direction.

Advantageous embodiments of the invention are specified in the dependent claims. The features listed individually in the dependent claims can be combined with one another in a technologically meaningful manner and can define further embodiments of the invention. In addition, the features specified in the claims are specified and explained in more detail in the description, with further preferred embodiments of the invention being presented.

According to an advantageous embodiment of the invention, it can be provided that the first plate element and/or the second plate element and/or the third plate element have/have a substantially circular outer contour. The advantage of this embodiment is that a uniform axial creepage distance can be defined over the circular outer contour in the circumferential direction of the shaft, whereby the risk of an undesirable current flashover can be further reduced.

According to a further preferred development of the invention, it can also be provided that at least one of the plate elements has an outer contour that differs from another of the plate elements. In this context, it is particularly preferred that two plate elements differ in terms of their diameter.

Furthermore, according to a likewise advantageous embodiment of the invention, it can be provided that the second plate element is arranged between the first plate element and the third plate element on the shaft of the spacer element, and the second plate element has an outer contour that differs from the other plate elements. In this context, it is also preferred that the second plate element has a larger diameter than the first and third plate elements.

According to another particularly preferred embodiment of the invention, it can be provided that the shaft of the spacer element engages in a corresponding opening of one of the rail tracks at a first distal shaft end and/or the shaft of the spacer element engages in a corresponding opening of one of the rail tracks at a second distal shaft end. This makes it possible in particular to easily mount and pre-assemble the high-voltage terminal. It is particularly preferred that the first shaft end can be manually inserted into the corresponding opening of one of the rail tracks by means of a slight press fit. Similarly, it is also particularly preferred that the second shaft end can be manually inserted into the corresponding opening of one of the rail tracks by means of a slight press fit. This makes it possible to provide a particularly secure mechanical connection between the rail tracks. In particular, the slight press fit can prevent the pre-assembled high-voltage terminal from falling apart during subsequent handling, for example when being inserted into an injection molding tool.

Furthermore, the invention can also be further developed in such a way that one of the rail tracks rests on the first plate element and a rail track axially spaced therefrom rests on the third plate element of the spacer element. The comparatively large support surface thus provided enables a good mechanical connection and a secure axial stop to be formed between a spacer element and a rail track.

In a likewise preferred embodiment variant of the invention, it can also be provided that the spacer elements are designed to be substantially identical, which can then also have a positive influence on the manufacturing costs of the high-voltage terminal due to the high degree of uniformity.

It may also be advantageous to further develop the invention in such a way that the high-voltage terminal is at least partially surrounded by a plastic housing, which in particular also supports a secure positional fixation of the rail tracks to one another, as well as simplifies handling during connection and integration of the high-voltage terminal.

The object of the invention is also achieved by a stator of an electrical machine comprising a high-voltage terminal according to one of claims 1-8.

• • Bereitstellung einer Mehrzahl von Schienensträngen,
• • Bereitstellung einer Mehrzahl von Abstandselementen, die jeweils ein erstes Tellerelement, ein zweites Tellerelement und wenigstens ein drittes Tellerelement aufweisen, welche beabstandet zueinander an einer Welle des Abstandselement angeordnet sind,
• • Anordnung der Schienenstränge in der Art, dass wenigstens drei Leiterphasen aus zumindest zwei im Wesentlichen parallel verlaufenden Schienensträngen gebildet sind,
• • und Positionierung der Abstandselemente zwischen den Schienensträngen, so dass die Schienenstränge über die Abstandselemente gegeneinander elektrisch isolierend sowie zueinander beabstandet verbunden sind,
• • Umspritzung der Bauteilgruppe bestehend aus den Schienensträngen und den Abstandselementen mit einem Kunststoff.

The object of the invention is further achieved by a method for producing a high-voltage terminal for a stator comprising the following steps:

• • Provision of a plurality of rail tracks,
• • Providing a plurality of spacer elements, each having a first plate element, a second plate element and at least one third plate element, which are arranged at a distance from one another on a shaft of the spacer element,
• • Arrangement of the rail tracks in such a way that at least three conductor phases are formed from at least two essentially parallel rail tracks,
• • and positioning the spacer elements between the rail tracks so that the rail tracks are connected via the spacer elements in an electrically insulating manner and spaced apart from each other,
• • Overmolding of the component group consisting of the rail sections and the spacer elements with a plastic.

In particular, the electric machine is dimensioned such that vehicle speeds of more than 50 km/h, preferably more than 80 km/h and in particular more than 100 km/h can be achieved. The electric motor particularly preferably has an output of more than 30 kW, preferably more than 50 kW and in particular more than 70 kW. It is further preferred that the electric machine provides speeds of more than 5,000 rpm, particularly preferably more than 10,000 rpm, very particularly preferably more than 12,500 rpm.

For the purposes of this application, motor vehicles are considered to be land vehicles that are moved by mechanical power without being tied to railway tracks. A motor vehicle can, for example, be selected from the group of passenger cars (PCs), lorries (HGVs), mopeds, light motor vehicles, motorcycles, buses (KOM) or tractors.

The high-voltage terminal can preferably be connected to power electronics and supplied with current from them. The power electronics can be accommodated in an inverter housing. The inverter housing can preferably be formed from a metallic material, particularly preferably from aluminum, gray cast iron or cast steel, in particular by means of a primary forming process such as casting or die casting. The inverter housing particularly preferably has a pot-like spatial shape. In this context, it is particularly preferable that the housing cover can be inserted into the pot-like inverter housing. Alternatively, it would also be conceivable for the housing cover to rest on the pot-like inverter housing and cover its opening. The inverter housing can also be part of the motor housing or vice versa. This means that the inverter housing is completely or partially formed in one piece, in particular monolithically, with the motor housing.

The power electronics accommodated in the inverter housing can be provided in particular for an electric machine of an electrically operated drive train of a motor vehicle. The power electronics are preferably a combination of different components which control or regulate a current to the electric machine of the axle drive train, preferably including the peripheral components required for this, such as cooling elements or power supplies. In particular, the power electronics contain one or more power electronics components which are designed to control or regulate a current. These are particularly preferably one or more power switches, e.g. power transistors. The power electronics particularly preferably have more than two, particularly preferably three separate phases or current paths, each with at least one of its own power electronics component.

The power electronics are preferably designed to control or regulate a power with a peak power, preferably continuous power, of at least 10 W, preferably at least 100 W, particularly preferably at least 1000 W per phase.

The power electronics preferably additionally have control electronics and/or sensor electronics for the electrical machine. The power electronics module preferably has at least one motor current connection and/or one electrical signal connection. The electrical machine can thus be operated by means of the power electronics module in that the power electronics module conducts current into a stator winding of the stator of the electrical machine.

The invention will be explained in more detail below with reference to figures without limiting the general inventive concept.

• 1 eine perspektivische Ansicht auf ein Hochvolt-Terminal ohne ein Kunststoffgehäuse,
• 2 eine Detailansicht auf die Abstandselemente und deren korrespondierenden Schienenstränge in einer Schnittdarstellung,
• 3 ein Abstandselement in einer Aufsicht,
• 4 eine perspektivische Ansicht auf das aus 1 bekannte Hochvolt-Terminal jedoch mit einem Kunststoffgehäuse,

It shows:

• 1 a perspective view of a high-voltage terminal without a plastic housing,
• 2 a detailed view of the spacer elements and their corresponding rail tracks in a sectional view,
• 3 a spacer element in a top view,
• 4 a perspective view of the 1 known high-voltage terminal but with a plastic housing,

The 1 shows a high-voltage terminal 1 for a stator, comprising at least three conductor phases 3, 4, 5 for electrically connecting the high-voltage terminal 1 to a power electronics 6 for supplying current to a winding of the stator. Each of the at least three conductor phases 3, 4, 5 is formed from at least two essentially parallel rail strands 7a, 7b, 8a, 8b, 9a, 9b, which are connected in an electrically insulating manner and spaced apart from one another via a plurality of spacer elements 10. In addition to the three conductor phases 3, 4, 5, the high-voltage terminal 1 also has a star phase 20.

As can be seen from the summary of the 1-3 As can be clearly seen, the spacer elements 10 each have a first plate element 11, a second plate element 12 and a third plate element 13, which are arranged at a distance from one another on a shaft 14 of the spacer element 10 and each protrude from the shaft 14 in the radial direction. The first plate element 11 and the second plate element 12 as well as the third plate element 13 have a substantially circular outer contour 15 and are formed coaxially to the shaft 14 on the latter.

In the embodiment shown, the second plate element 12 is arranged between the first plate element 11 and the third plate element 13 on the shaft 14 of the spacer element 10. The second plate element 11 has an outer contour 15 that differs from the other plate elements 11, 13 in that it has a correspondingly larger diameter.

The shaft 14 of the spacer element 10 engages at a first distal shaft end 16a in a corresponding opening 17 of one of the rail tracks 7a, 7b, 8a, 8b, 9a, 9b. Analogously, the shaft 14 of the spacer element 10 also engages at a second distal shaft end 16b in a corresponding opening 18 of one of the rail tracks 7a, 7b, 8a, 8b, 9a, 9b.

As a result, one of the rail tracks 7a, 7b, 8a, 8b, 9a, 9b rests on the first plate element 11 and a rail track 7a, 7b, 8a, 8b, 9a, 9b axially spaced apart from it rests on the third plate element 13 of the spacer element 10.

In the embodiment shown, the spacer elements 10 are essentially identical.

The 4 shows that from the 1 known high-voltage terminal 1 in a plastic housing 21, which for example is attached to the 1 known high-voltage terminal 1 was injected.

This high-voltage terminal 1 can be 4 For example, it can be produced as follows.

First, a plurality of rail tracks 7a, 7b, 8a, 8b, 9a, 9b are provided, as well as a plurality of spacer elements 10, each of which has a first plate element 11, a second plate element 12 and at least one third plate element 13, which are arranged at a distance from one another on a shaft 14 of the spacer element 10.

Firstly, the arrangement of the rail tracks 7a, 7b, 8a, 8b, 9a, 9b is then carried out in such a way that at least three conductor phases 3, 4, 5 are formed from at least two essentially parallel rail tracks 7a, 7b, 8a, 8b, 9a, 9b, wherein the positioning of the spacer elements 10 between the rail tracks 7a, 7b, 8a, 8b, 9a, 9b is carried out in such a way that the rail tracks 7a, 7b, 8a, 8b, 9a, 9b are connected via the spacer elements 10 in an electrically insulating manner from one another and spaced apart from one another.

Finally, the pre-assembled component group consisting of the rail strands 7a, 7b, 8a, 8b, 9a, 9b and the spacer elements 10 is then encapsulated with a plastic, for example in an injection molding tool.

The invention is not limited to the embodiments shown in the figures. The above description is therefore not to be regarded as restrictive, but as explanatory. The following patent claims are to be understood in such a way that a named feature is present in at least one embodiment of the invention. This does not exclude the presence of further features. If the patent claims and the above description define 'first' and 'second' features, this designation serves to distinguish between two similar features without establishing a ranking.

list of reference symbols

1

high-voltage terminal

3

ladder phase

4

ladder phase

5

ladder phase

6

power electronics

7

rail line

8

rail line

9

rail line

10

spacers

11

plate element

12

plate element

13

plate element

14

Wave

15

outer contour

16

shaft end

17

opening

18

opening

20

star phase

21

plastic housing

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions.

Cited patent literature

• DE 10 2019 111 825 A1 [0010]

Cited non-patent literature

• Journal ATZ 63rd year, 05/20 6, pages 360-365 by Erik Schneider, Frank Fickl, Bernd Cebulski and Jens Liebold [0003]

Claims (10)

High-voltage terminal (1) for a stator, comprising at least three conductor phases (3, 4, 5) for electrically connecting the high-voltage terminal (1) to power electronics (6) for supplying current to a winding of the stator, wherein each of the at least three conductor phases (3, 4, 5) is formed from at least two essentially parallel rail strands (7a, 7b, 8a, 8b, 9a, 9b) which are connected via a plurality of spacer elements (10) in an electrically insulating manner from one another and at a distance from one another, characterized in that the spacer elements (10) each have a first plate element (11), a second plate element (12) and at least one third plate element (13), which are arranged at a distance from one another on a shaft (14) of the spacer element (10) and each protrude from the shaft (14) in the radial direction. High-voltage terminal (1) after claim 1 , characterized in that the first plate element (11) and/or the second plate element (12) and/or the third plate element (13) have/have a substantially circular outer contour (15). High-voltage terminal (1) after claim 1 or 2 , characterized in that at least one of the plate elements (11,12,13) has an outer contour (15) which differs from another of the plate elements (11,12,13). High-voltage terminal (1) according to one of the preceding claims, characterized in that the second plate element (12) is arranged between the first plate element (11) and the third plate element (13) on the shaft (14) of the spacer element (10), and the second plate element (11) has an outer contour (15) that differs from the other plate elements (11, 13). High-voltage terminal (1) according to one of the preceding claims, characterized in that the shaft (14) of the spacer element (10) engages at a first distal shaft end (16) in a corresponding opening (17) of one of the rail tracks (7a, 7b, 8a, 8b, 9a, 9b) and/or the shaft (14) of the spacer element (10) engages at a second distal shaft end (16) in a corresponding opening (18) of one of the rail tracks (7a, 7b, 8a, 8b, 9a, 9b). High-voltage terminal (1) according to one of the preceding claims, characterized in that one of the rail tracks (7a, 7b, 8a, 8b, 9a, 9b) rests on the first plate element (11) and a rail track (7a, 7b, 8a, 8b, 9a, 9b) axially spaced therefrom rests on the third plate element (13) of the spacer element (10). High-voltage terminal (1) according to one of the preceding claims, characterized in that the spacer elements (10) are designed essentially identically. High-voltage terminal (1) according to one of the preceding claims, characterized in that the high-voltage terminal (1) is at least partially surrounded by a plastic housing (21). Stator of an electrical machine (19) comprising a high-voltage terminal (1) according to one of the preceding claims. Method for producing a high-voltage terminal (1) for a stator, comprising the following steps: • Providing a plurality of rail tracks (7a, 7b, 8a, 8b, 9a, 9b), • Providing a plurality of spacer elements (10), each of which has a first plate element (11), a second plate element (12) and at least one third plate element (13), which are arranged at a distance from one another on a shaft (14) of the spacer element (10), • Arranging the rail tracks (7a, 7b, 8a, 8b, 9a, 9b) in such a way that at least three conductor phases (3, 4, 5) are formed from at least two essentially parallel rail tracks (7a, 7b, 8a, 8b, 9a, 9b), • and positioning the spacer elements (10) between the rail tracks (7a, 7b, 8a, 8b, 9a, 9b), so that the rail tracks (7a, 7b, 8a, 8b, 9a, 9b) are connected via the spacer elements (10) in an electrically insulating manner and spaced apart from one another, • Overmolding the component group consisting of the rail tracks (7a, 7b, 8a, 8b, 9a, 9b) and the spacer elements (10) with a plastic.

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