Stator with cooling for an electrical contact element

Abstract

A stator for an electric machine is described, wherein the stator comprises a stator body with stator windings. The stator further comprises at least one electrically conductive contact element arranged on an end face of the stator body, which is configured to be electrically connected to a power supply for providing a phase current for the stator windings, and at least one coolant channel configured to carry coolant for cooling the contact element.

Description

[0001] The invention relates to an electrical machine, such as a synchronous machine. In particular, the invention relates to the cooling of the electrical connections, i.e., the contact elements, of the stator of an electrical machine.

[0002] A vehicle powered at least partially by electricity comprises an electric machine for propelling the vehicle. The electric machine includes a stator that encloses a rotor. Furthermore, the electric machine typically has a coolant circuit to cool the machine, particularly the stator windings. The coolant (especially a liquid coolant, such as machine oil) can be guided through hollow coolant channels within the stator body. The stator body can be designed as a laminated core (especially a laminated core with baked enamel technology). The coolant can also be sprayed onto the winding head at an end face of the stator body via nozzles.

[0003] The electrical windings of the stator are connected to an electrical power supply, in particular an inverter, via electrically conductive contact elements.

[0004] DE 10 2022 121 880 A1 describes a stator with axial fluid channels that have openings to direct cooling fluid to the base body of a contacting element. US 2021 / 0 013 764 A1 describes an electric machine with a cover that has cooling channels. DE 11 2021 001 349 T5 describes a cooling system for electric motor components. JP 2011-234 590 A describes an electric machine with a cooled electrical contact part.

[0005] This document addresses the technical challenge of enabling particularly efficient and reliable cooling of the contact elements of the stator of an electric machine.

[0006] The problem is solved by the individual independent claims. Advantageous embodiments are described, inter alia, in the dependent claims. It should be noted that additional features of a claim dependent on an independent claim, without the features of the independent claim itself or only in combination with a subset of the features of the independent claim, can constitute a separate invention independent of the combination of all features of the independent claim, which can be made the subject of an independent claim, a divisional application, or a subsequent application. This applies equally to technical teachings described in the description, which can constitute an invention independent of the features of the independent claims.

[0007] According to one aspect, a stator for an electric machine, in particular for a synchronous machine, is described. The stator comprises a stator body with stator windings. One or more, in particular N (with N ≥ 3), phase currents can be conducted through the stator windings, e.g., to generate a rotating electromagnetic field for driving the rotor of the electric machine. A winding head can be formed by the stator windings on one or both end faces of the stator body.

[0008] The stator comprises at least one electrically conductive contact element arranged on an end face of the stator body, configured to be electrically connected to a power supply to provide a phase current for the stator windings. The stator typically comprises N electrically conductive contact elements. Each electrically conductive contact element can be made of electrically conductive material (e.g., a metal such as aluminum or copper). Furthermore, an electrically conductive contact element can be electrically connected (e.g., via a screw, plug, and / or weld connection) to a complementary contact element of the power supply (e.g., an inverter).

[0009] The stator can be designed such that the winding head is arranged on an end face of the stator body between the end face of the stator body and the one or more, in particular the N, contact elements.

[0010] The stator comprises at least one coolant channel configured to supply coolant (in particular a cooling fluid, such as oil) for cooling the contact element. The stator can, in particular, have at least one coolant channel for each of the N contact elements, configured to supply coolant for cooling the respective contact element.

[0011] This describes a stator with one or more actively cooled contact elements (especially high-voltage terminals). This allows for the efficient and reliable provision of an electric machine for powering a motor vehicle.

[0012] The following describes the characteristics of a contact element. It should be noted that these characteristics are applicable to all N contact elements of the stator.

[0013] The contact element has an internal coolant channel designed to guide coolant (in particular a cooling fluid) through the electrically conductive material of the contact element. The internal coolant channel is formed as a recess within the electrically conductive material of the contact element. Furthermore, the internal coolant channel can run in a meandering and / or serpentine pattern through the contact element, particularly through the electrically conductive material of the contact element (in order to increase the surface area wetted by the coolant and thus the cooling efficiency).

[0014] The contact element, in particular the electrically conductive material of the contact element, can have a certain total length in the axial direction of the stator. The inner coolant channel of the contact element can extend in the axial direction over 40% or more, in particular over 50% or more, of the total length.

[0015] The internal coolant channel runs from an inlet (for coolant) to an outlet (for coolant). The inlet can be located on a first, in particular upper, side of the contact element, and the outlet can be located on an opposite second, in particular lower, side of the contact element.

[0016] By providing an internal coolant channel within the (electrically conductive material of the) contact element, particularly reliable cooling of the contact element can be achieved.

[0017] The stator may have a coolant supply channel designed to direct coolant from the end face of the stator body to the contact element, in particular to the inlet of the inner coolant channel of the contact element. The coolant supply channel may extend from the end face of the stator body, past the winding head, to the contact element.

[0018] The stator body can have one or more axial coolant channels extending through at least a portion of the stator body, each configured to convey coolant. The supplying coolant channel can be configured to convey coolant from at least one of the axial coolant channels to the contact element, in particular to the inlet of the inner coolant channel of the contact element.

[0019] By providing a coolant channel to the contact element, particularly efficient cooling of the contact element can be achieved (with coolant from one or more axial coolant channels of the stator body).

[0020] The stator can include a draining coolant channel configured to direct coolant away from the contact element, particularly from the outlet of the contact element's inner coolant channel. The draining coolant channel can be configured to direct the coolant directed from the contact element, particularly from the outlet of the contact element's inner coolant channel, to the winding head. The draining coolant channel can, in particular, be configured to direct the coolant to one or more nozzles (e.g., each arranged at one end of the draining coolant channel), each configured to spray coolant from the draining coolant channel onto the winding head.

[0021] By providing a cooling channel for cooling, particularly efficient and reliable cooling of the stator, especially of the stator winding head, can be achieved.

[0022] The stator can have a coolant circuit configured to pump coolant into the at least one coolant channel for cooling the contact element. The coolant circuit can further be configured to temper the coolant used to cool the contact element before it is pumped back into the at least one coolant channel.

[0023] The coolant circuit can be configured to cool the stator windings with coolant in a main circuit. Furthermore, the coolant circuit can be configured to branch off coolant from the main circuit to cool the contact element.

[0024] By diverting coolant to cool one or more contact elements, particularly efficient cooling of the contact elements can be achieved.

[0025] According to another aspect, an electrical machine, in particular a synchronous machine, is described as having a rotor and a stator, the stator being designed as described in this document.

[0026] The electric machine can be configured to direct coolant from an outer surface of the stator body into one or more axial coolant channels of the stator body, particularly at a location centrally located in the axial direction between two stator body sections. The electric machine can further be configured to direct coolant from the one or more axial coolant channels into at least one coolant channel for cooling the contact element at at least one end face of the stator body. The coolant can then be collected. This coolant can be returned to the one or more axial coolant channels (after temperature control, in particular cooling).

[0027] This allows a coolant circuit to be provided for efficient and reliable cooling of the stator windings and / or the winding heads and / or the contact elements of the stator.

[0028] According to another aspect, a (road) motor vehicle (in particular a passenger car or a truck or a bus or a motorcycle) is described that includes the electric machine described in this document.

[0029] It should be noted that the devices and systems described in this document can be used both alone and in combination with other devices and systems described in this document. Furthermore, any aspect of the devices and systems described in this document can be combined with one another in a variety of ways. In particular, the features of the claims can be combined with one another in a variety of ways. Features listed in parentheses are to be understood as optional features.

[0030] The invention will now be described in more detail using exemplary embodiments. Fig. 1a an exemplary electric machine; Fig. 1b an exemplary winding head on an end face of a stator; Fig. 2a an isometric view of an exemplary multi-part stator body; Fig. 2b an example stator lamination; Fig. 3a an exemplary isometric view of the electrical contact elements on an end face of the stator; Fig. 3b and Fig. 3c shows a sectional view of exemplary coolant channels for cooling the contact elements; Fig. 3D shows an exemplary contact element with an internal coolant channel; and Fig. 3e an exemplary draining coolant channel.

[0031] As stated at the outset, this document deals with increasing the reliability of the cooling of the contact elements of a stator in an electric machine. In this context, it shows Fig. Figure 1a shows an exemplary electric machine 100 in a view perpendicular to the shaft 101 of the electric machine 100. The shaft 101 of the electric machine 100 can correspond to the longitudinal axis of the stator 110 and / or the rotational axis of the rotor 120 of the electric machine 100. The shaft 101 runs along the z-axis of the Cartesian coordinate system shown.

[0032] The electric machine 100 comprises a stator 110 with several stator windings 111 arranged at different angular positions around the rotational axis of the rotor 120 and configured to generate a rotating electromagnetic field. The stator 110 is enclosed by a housing 135 of the electric machine 100. The individual stator windings 111 can each be arranged in a stator slot between two directly adjacent stator teeth 113 of the stator 110. An air gap 102 is arranged between the stator 110 and the rotor 120.

[0033] Furthermore, the electric machine 100 comprises the rotor 120, which is driven by the rotating magnetic field generated by the stator 110. The rotor 120 is rigidly connected to the shaft 101 driven by the electric machine 100 (which is connected to or corresponds to the rotor axis of the rotor 120). The rotor 120 comprises a rotor body 122.

[0034] The rotor 120 of an electric machine 100 can have a rotor body 122 consisting of a laminated iron core (e.g., composed of mutually insulated sheets). Similarly, the stator body of the stator 110 can also be composed of individual (mutually electrically insulated) stator laminations (e.g., iron sheets).

[0035] The stator 110 extends along the rotational axis of the rotor 120, or along the longitudinal axis of the stator 110, from a first end face to an opposite second end face. The stator 110 has different magnetic stator teeth 113, which are arranged at various angular positions (uniformly distributed) around the rotational axis of the rotor 120. Windings 111 can be arranged around each of the individual stator teeth 113, generating a magnetic field. The individual stator teeth 113 can thus form magnetic poles of the stator 110. The windings 111 form a winding head at each of the end faces of the stator 110.

[0036] A stator slot is formed between two directly adjacent stator teeth 113 of the stator 110, in which the windings 111 are arranged. A stator slot extends along the longitudinal axis (i.e., along the z-axis) from the first end face to the opposite second end face of the stator 110. The windings 111 arranged in a stator slot can be electrically insulated from the (electrically conductive) stator body by means of slot insulation.

[0037] Fig. Figure 1b illustrates the winding head 115 formed by the stator windings 111 on an end face 117 of the stator 110. The winding head 115 is typically cooled with a (liquid) coolant 130 (e.g., oil). The coolant 130 can be sprayed onto the winding head 115, for example, by one or more nozzles (not shown). In the stator 110 described in this document, the coolant 130 for cooling the winding head 115 can be efficiently supplied from coolant channels in the stator body 118 of the stator 110.

[0038] Fig. Figure 2a shows an exemplary multi-part stator body 118 of a stator 110. The stator body 118 comprises a first sub-body 201 and a second sub-body 202, which are arranged one behind the other along the longitudinal axis of the stator body 118 (i.e., along the axis of rotation of the rotor 120). The sub-bodies 201 and 202 can each be composed of a plurality of stator laminations, e.g., 50 or more, or 100 or more stator laminations. The individual stator laminations can be at least partially identical. If necessary, the stator laminations can be at least partially different in order to effect a targeted steering and / or guidance of the coolant through the stator body 118. Furthermore, the two sub-bodies 201, 202 can be identical in construction, so that each of the two sub-bodies 201, 202 forms one half of the base body 201, 202 of the stator body 118.

[0039] The stator body 118 can have one or more hollow coolant channels 205 in the stator yoke and / or in the individual stator teeth 113, each extending in the axial direction, i.e., longitudinally. Coolant 130 can be passed through each of the individual axial coolant channels 205 to cool the stator windings 111.

[0040] A central stator component 203, in particular a central stator lamination or lamination stack, can be arranged between the two sub-bodies 201, 202, bearing against the central end faces 216 of the two sub-bodies 201, 202. The central stator component 203 can have a stator yoke and stator teeth 113. Furthermore, the central stator component 203 can be configured to direct coolant 130 from outside the stator body 118 into the axial coolant channels 205 of the two sub-bodies 201, 202.

[0041] The in Fig. The stator body 118 shown in Figure 2a has an end-face stator lamination 210 on each of the outer end faces 116 of the sub-bodies 201 and 202. In particular, a first end-face stator lamination 210 is arranged on the outer end face 116 of the first sub-body 201, and a second end-face stator lamination 210 is arranged on the outer end face 116 of the second sub-body 202. The individual end-face (or nozzle) stator laminations 210 can each have nozzles 212, which are supplied with coolant 130 from the individual axial coolant channels 205. The nozzles 212 can be arranged evenly distributed around the central longitudinal axis of the stator 110. Each nozzle 212 can direct a coolant jet onto the winding head 115 of the stator 110.

[0042] On one of the two end faces 117 of the stator 110, as exemplified in Fig. Figure 3a shows that electrical contact elements 300 are arranged through which the stator windings 111 of the stator 110 are supplied with electric current. The stator 110 can have N different phases (e.g., N=3) to generate a rotating field for driving the rotor 120. Furthermore, the stator 110 can have N contact elements 300 for the corresponding N phases. In the figure shown in Fig. In the example shown in Figure 3a, the individual contact elements 300 are each designed as circular cylindrical, electrically conductive bolts. Each individual contact element 300 can be electrically connected to a complementary contact element of a power supply, in particular an inverter.

[0043] The electrical contact elements 300 can be attached to a support element 310, the support element 310 being in turn attached to the end face 117 of the stator 110, e.g., to a star disk on the end face 117 of the stator 110. In the Fig. In the example shown in 3a, the support element 310 is designed as a support plate that extends from the end face 117 of the stator 110, over the winding head 115, to the contact elements 300. The support element 310 can be made at least partially or completely of plastic.

[0044] The individual contact elements 300 are, as exemplified in the Fig. 3b and Fig. Figure 3c shows each contact element 300 connected via a supply coolant channel 315 to one or more of the axial coolant channels 205 of the stator body 118 in a fluid-conducting manner (and sealing against the stator-rotor space, in particular against the gap 102 between the stator 110 and the rotor 120). In particular, the stator 110 can have a supply coolant channel 315 for each individual contact element 300, configured to supply coolant 130 from at least one axial coolant channel 205 to the respective contact element 300 (without coolant 130 entering the space between the stator 110 and the rotor 120). The individual supply coolant channels 315 can each run within the support element 310.

[0045] Fig. Figure 3d shows an exemplary contact element 300, which has an internal coolant channel 325 that runs, for example, in a meandering pattern, within the contact element 300, in particular within the electrically conductive material of the contact element 300. The internal coolant channel 325 can be supplied with coolant 130 via an inlet 316 located on a first side of the contact element 300. The coolant 130 can then flow through the internal coolant channel 325 and exit the internal coolant channel 325 via an outlet 326 located on an opposite second side of the contact element 300. As shown in Figure 3d, the coolant 130 can flow through the internal coolant channel 325 and exit it via an outlet 326 located on a second, opposite side of the contact element 300. Fig. As can be seen in Figure 3c, the inlet 316 of the inner coolant channel 325 is fluid-conducting and connected to the supplying coolant channel 315. Furthermore, the outlet 326 can be fluid-conducting and connected to a discharging coolant channel 335, the discharging coolant channel 335 being configured to return the coolant 130 to the coolant circuit of the stator 110. The discharging coolant channel 335 can, for example, be configured to direct the coolant 130 to an opening 336, in particular to a nozzle, which is designed to direct the coolant 130 from the discharging coolant channel 335 onto the winding head 115, in particular to spray it (see Figure 3c). Fig. 3b and Fig. 3e).

[0046] The contact elements 300 and the support element 310 can be part of a connection assembly of the stator 110 (whereby the connection assembly is attached to the stator 110, in particular to an end face 117 of the stator 110).

[0047] The measures described in this document enable efficient cooling of the contact elements 300 (i.e., the high-voltage terminals) and, if applicable, the winding head 115 (located between the contact elements 300 and the end face 117 of the stator 110). This can be achieved by supplying each of the individual contact elements 300, which each serve to conduct the current from the inverter to the stator windings 111, with a coolant 130 (e.g., motor oil). For this purpose, the terminal assembly of the stator 110 can be integrated into the coolant circuit of the stator 110.

[0048] A portion of the coolant 130 from the winding head cooling can be diverted (e.g., directly from one or more axial coolant channels 205). The diverted coolant 130 is guided through an internal coolant channel 325 of the respective contact element 300. The internal coolant channel 325 can be serpentine in shape to achieve the largest possible surface wetting.

[0049] The coolant 130 can then be transferred from the respective contact element 300 to a draining coolant channel 335 (which is, for example, part of the connection assembly, which may be made of plastic). The draining coolant channel 335 can extend radially and / or circumferentially. The coolant 130 can be directed via the draining coolant channel 335 and one or more nozzles 336 to the winding head 115 and, if necessary, sprayed onto the winding head 115.

[0050] The measures described in this document ensure particularly efficient and reliable heat dissipation from the contact elements 300 of the stator 110 of an electric machine 100.

[0051] The present invention is not limited to the embodiments shown. In particular, it should be noted that the description and the figures are intended only to illustrate the principle of the proposed devices and systems by way of example.

Claims

[1] Stator (110) for an electric machine (100); wherein the stator (110) comprises, - a stator body (118) with stator windings (111); - at least one electrically conductive contact element (300) arranged on an end face (117) of the stator body (118), which is designed to be electrically connected to a power supply for providing a phase current for the stator windings (111); - at least one coolant channel (315, 325, 335) configured to carry coolant (130) for cooling the contact element (300); wherein - the contact element (300) has an internal coolant channel (325) configured to guide coolant (130) through electrically conductive material of the contact element (300); and - the inner coolant channel (325) is formed as a recess within the electrically conductive material of the contact element (300); - a supply coolant channel (315) configured to direct coolant (130) from the end face (117) of the stator body (118) to an inlet (316) of the inner coolant channel (325) of the contact element (300); and - a winding head (115) of the stator windings (111) arranged on the end face (117) of the stator body (118); wherein - the winding head (115) is arranged between the end face (117) of the stator body (118) and the at least one contact element (300); and - the supplying coolant channel (315) runs from the end face (117) of the stator body (118), past the winding head (115), to the inflow (316) of the inner coolant channel (325) of the contact element (300). [2] Stator (110) according to claim 1, wherein the inner coolant channel (325) runs meanderingly and / or serpentine-like through the contact element (300), in particular through the electrically conductive material of the contact element (300). [3] Stator (110) according to any one of the preceding claims, wherein - the inner coolant channel (325) runs from the inlet (316) to an outlet (326); and - the inflow (316) is arranged on a first, in particular upper, side of the contact element (300) and the outflow (316) is arranged on an opposite second, in particular lower, side of the contact element (300). [4] Stator (110) according to any one of the preceding claims, wherein - the contact element (300), in particular the electrically conductive material, has a total length in the axial direction of the stator (110); and - the inner coolant channel (325) extends in the axial direction over 40% or more, in particular over 50% or more, of the total length. [5] Stator (110) according to any one of the preceding claims, wherein - the stator body (118) has one or more axial coolant channels (205) extending in an axial direction through at least a part of the stator body (118), each configured to conduct coolant (130); and - the supplying coolant channel (315) is designed to supply coolant (130) from at least one of the axial coolant channels (205) to the contact element (300), in particular to the inflow (316) of the inner coolant channel (325) of the contact element (300). [6] Stator (110) according to one of the preceding claims, wherein the stator (110) comprises a draining coolant channel (335) which is configured to drain coolant (130) away from the contact element (300), in particular from a drain (326) of an inner coolant channel (325) of the contact element (300). [7] Stator (110) according to claim 6, wherein - the stator (110) has a winding head (115) of the stator windings (111) arranged on the end face (117) of the stator body (118); - the winding head (115) is arranged in particular between the end face (117) of the stator body (118) and the at least one contact element (300); and - the draining coolant channel (335) is designed to direct the coolant (130) directed away from the contact element (300), in particular from the drain (326) of the inner coolant channel (325) of the contact element (300), to the winding head (115). [8] Stator (110) according to claim 7, wherein the draining coolant channel (335) is configured to direct the coolant (130) to one or more nozzles (336), each of which is configured to spray coolant (130) from the draining coolant channel (335) onto the winding head (115). [9] Stator (110) according to one of the preceding claims, wherein the stator (110) has a coolant circuit which is configured to - to pump coolant (130) into at least one coolant channel (315, 325, 335) for cooling the contact element (300); and - To temper the coolant (130) used to cool the contact element (300) before the coolant (130) is again pumped into the at least one coolant channel (315, 325, 335). [10] Stator (110) according to claim 9, wherein - the coolant circuit is designed to cool the stator windings (111) with coolant (130) in a main circuit; and - To divert coolant (130) from the main circuit to cool the contact element (300). [11] Stator (110) according to any one of the preceding claims, wherein - the stator (110) has N electrically conductive contact elements (300), with N≥3; and - the stator (110) has at least one coolant channel (315, 325, 335) for each of the N contact elements (300), which is designed to carry coolant (130) for cooling the respective contact element (300). [12] Stator (110) for an electric machine (100); wherein the stator (110) comprises, - a stator body (118) with stator windings (111); - at least one electrically conductive contact element (300) arranged on an end face (117) of the stator body (118), which is configured to be electrically connected to a power supply for providing a phase current for the stator windings (111); and - at least one coolant channel (315, 325, 335) configured to carry coolant (130) for cooling the contact element (300); wherein - the contact element (300) has an internal coolant channel (325) which is designed to guide coolant (130) through electrically conductive material of the contact element (300); - the inner coolant channel (325) is formed as a recess within the electrically conductive material of the contact element (300); - the inner coolant channel (325) runs from an inlet (316) to an outlet (326); - the inflow (316) is arranged on a first, upper, side of the contact element (300) and the outflow (316) is arranged on an opposite second, lower, side of the contact element (300); and - the inner coolant channel (325) runs in a meandering and / or serpentine pattern through the electrically conductive material of the contact element (300). [13] Electric machine (100) comprising a rotor (120) and a stator (110) configured according to any one of the preceding claims; wherein the electric machine (100) is configured, - to direct coolant (130) from an outer surface of the stator body (118) of the stator (110) into one or more axial coolant channels (205) of the stator body (118) of the stator (110), in particular at a location arranged centrally in the axial direction between two sub-bodies (201, 202) of the stator body (118); and - to direct coolant (130) from the one or more axial coolant channels (205) into the at least one coolant channel (315, 325, 335) for cooling the contact element (300) at at least one end face (117) of the stator body (118) of the stator (110).

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