AT524472A1 - Stator for an electric machine - Google Patents

Abstract

The invention relates to a stator (1) for an electrical machine, with a plurality of slots (4), in each of which at least one electrical conductor (5) is arranged, the electrical conductors (5) having conductor ends (6) which the slots ( 4) protrude in an axial direction (2), and which form a first end winding (7) and a second end winding (8), and with a coolant channel (9) which has a coolant inlet (10) and a coolant outlet (11), wherein the coolant channel (9) is arranged to run around at least one of the first or the second winding overhang (7, 8), and wherein a closing element (24) is arranged adjacent to the grooves (4) in the axial direction (2), through which the conductor ends (5) protrude, the grooves (4) each being sealed with at least one sealing element (20), and the closing elements (24) being connected via the sealing elements (20) to the component forming the grooves (4).

Description

through which the conductor ends protrude. The invention further relates to an electrical machine comprising a stator.

The invention also relates to a method for cooling a stator for an electrical machine, in which a plurality of slots are formed, in each of which at least one electrical conductor is arranged, the electrical conductors being formed with conductor ends which are arranged projecting beyond the slots in an axial direction , and with which a first winding overhang and a second winding overhang is formed, and wherein a coolant channel with a coolant inlet and a coolant outlet is formed in the stator, and wherein in the axial direction of the slots then in each case a closing element on

is arranged, through which the conductor ends are arranged projecting.

It is known that in a stator of an electrical machine during operation, heat is generated on the one hand in the laminated core and on the other hand in the windings. For this reason, stators are cooled, with different

most designs of cooling have been described.

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seen coolant line communicates.

Other examples of slot cooling are described in US 2011/0133580 A1 and WO 2019/183657 A1.

The winding head cooling is also already known from the prior art. For example, DE 102018 131 962 A1 describes a cooling duct for a winding overhang of an electrical machine, the cooling duct being designed in the form of a ring for guiding a cooling fluid with at least one inflow and at least one outflow and for arrangement around the winding overhang, and having an axially movable pressing part, which is arranged such that a cooling fluid on the pressing part

flowable and a contact pressure can be generated on the cooling channel.

The invention is based on the object of cooling an electrical machine

seem easy to design.

In the case of the stator mentioned at the outset, the object is achieved in that the grooves are each sealed with at least one sealing element, and that the closing elements are connected via the sealing elements to the structural element forming the grooves.

are partly connected.

The task is also solved with the electrical machine that has the inventive

having the appropriate stator.

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forming component are connected.

The advantage here is that with the at least one coolant channel around one of the two end windings, the cooling system can be configured more simply. This in turn allows the sealing levels in the system to be reduced, which means that a further system simplification can be achieved. In addition, this reduction can also reduce the risk of leakage. In comparison to exclusive slot cooling, a better degree of efficiency can also be achieved with direct cooling of the end windings, since there are no thick casting compounds between the coolant and the component to be cooled, which would impede the heat transfer into the coolant. The sealing of the grooves can be formed more easily with the sealing element, in particular also in production lines. In addition, with the groove seal, greater security against the ingress of coolant into the grooves can be achieved. As a result, the closing element arranged on the face side, which is sealed against the grooves, can consist of one material

hen, with which the machine manufacturability of the stator can be simplified.

According to one embodiment variant of the invention, it can be provided that the coolant channel is arranged around the first end winding and a further coolant channel is arranged around the second end winding. The cooling of the winding on both sides that can be achieved in this way can further improve the efficiency of the cooling system, which means that the unwanted temperature rise in the stator when the electric machine consumes or outputs power can be better controlled

can.

According to another embodiment variant of the invention, it can be provided that the coolant channel and the further coolant channel each have at least one coolant inlet and at least one coolant outlet. Due to the separation into two coolant circuits, different heat development can

genes in the two end windings can be mastered more easily.

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can.

For the same reason it can be provided according to further embodiment variants of the invention that the coolant channel and the further coolant channel have a common coolant inlet and a common coolant outlet and/or that the coolant inlet and the coolant outlet

let are arranged in a common connection element.

According to one embodiment variant, it can be provided that the closing elements are formed from a composite material, so that the sealing element can also better take over tasks relating to the mechanical stability of the coolant channel or coolant channels, with which the structure

the cooling of the stator can be further simplified.

It is also possible to improve the sealing of the grooves if, according to a further embodiment of the invention, the composite material of the closing elements consists of a combination of a hard material and a comparatively softer material, such as an elastomer, is combined to form the composite material. The softer material can optionally

form the sealing elements.

According to a further embodiment variant of the invention, it can be provided that the grooves are provided with an additional groove seal in the axial course

are in order to further improve the fluid tightness of the cooling system.

A simple "sealing" of the slots in the stator can be achieved if they are provided with an impregnating agent that prevents or reduces wetting of the slots with the coolant. However, the grooves can also be sealed by sealing elements, such as groove wedges or paper soaked with a coolant-repellent agent, which may also

tion of the electrical conductors in the grooves at least partially take over.

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central channel is formed.

According to another embodiment variant of the invention, it can be provided that a pressure difference of the conveying pressure of the coolant between the input side and the output side of the coolant channel or coolant channels is between 0.2 bar and 2 bar. With the invention, a low-pressure cooling system can thus be implemented which is structurally correspondingly simpler and liquid-tight

can be produced, and also has a lower energy requirement.

According to a further embodiment of the invention, it can be provided that a coolant is used for cooling that has a dynamic viscosity at 20° C. of at least 0.01 kg/m.s, in particular between 0.01 kg/m.s and 0.07 kg/m. m.s. It can thus be further simplified the sealing of the grooves, especially when due to the low-pressure cooling, the more viscous

coolant does not penetrate into the narrow grooves.

For a better understanding of the invention, this is based on the following

Figures explained in more detail.

They each show in a greatly simplified, schematic representation:

1 shows a longitudinal section through an electrical machine with a stator;

2 shows a section of a stator in longitudinal section;

3 shows a detail from a stator in the area of the end faces of the laminated core.

As an introduction, it should be noted that in the differently described embodiments, the same parts are provided with the same reference numbers or the same component designations, it being possible for the disclosures contained throughout the description to be applied to the same parts with the same reference numbers or the same component designations. Also are in the

Description selected location information, such as top, bottom, side, etc. on the

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information to be transferred to the new position in the event of a change in position.

In Fig. 1, a stator 1 for an electrical machine is shown in an end view. The electrical machine comprising this stator 1 is in particular a motor

or a generator.

In principle, such electrical machines and the stators used for them are known from the prior art, so that reference is made to this relevant prior art for further details. For the sake of completeness, it should only be mentioned at this point that the electrical machine preferably also includes a rotor which is arranged in the electrical machine, forming an air gap with respect to the stator 1 . The rotor can be arranged, for example, on a shaft so as to be non-rotatable. During operation of the electric machine designed as an electric motor, the rotor is set in rotary motion due to the generated magnetic fields. The stator 1 is basically

Can also be used without a rotor to generate a rotating field. The rotor itself can be designed according to the state of the art.

The stator 1 comprises a number of sheet metal elements (in particular electrical sheets) which are arranged one behind the other in an axial direction 2 and which are connected to one another to form a laminated core 22, as is known per se. In these sheet metal elements, grooves 4 that are open inwards are formed in a radial direction 3 . The exact number of grooves 4 depends on the desired size or

power of the electric machine.

The grooves 4 can have a wide variety of cross-sectional shapes (viewed in the direction of the axial direction 2). For example, the grooves 4 can have a round, oval, rectangular, square, trapezoidal, etc. cross-sectional shape. However, it should be pointed out that the slots 4 of a stator 1 preferably all have the same cross-sectional shape, although mixed variants with at least two different cross-sectional shapes are also possible.

men are possible.

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3 considered).

The grooves 4 are used to accommodate at least one electrical conductor 5 each

Slot 4. The electrical conductors 5 form the stator windings.

The electrical conductors 5 can be made from a wire. The wire can be round wire or flat wire, for example. Likewise, the stator windings can preferably be designed as so-called hairpins or I-pins.

be leading

One or more electrical conductors 5 can be provided per slot 4 . The number of electrical conductors 5 shown specifically in FIG. 1 is therefore not to be understood as limiting. Furthermore, the position and orientation of the electrical conductors 5 within the grooves 4 specifically shown in the figures is not restricted.

to understand.

The electrical conductors 5 have conductor ends 6 with which they protrude beyond the grooves 4 in the axial direction 2 on both sides. With these conductor ends 6, they form a first winding head 7 and a second winding head 8. In the winding heads 7, 8, electrical conductors 5 of the same phase are brought together and connected to one another. However, it is also possible for electrical conductors 5 of one phase to be bent over so far that they can be inserted into a further slot 4 and guided to the other end winding 7 or 8 in each case. Since such configurations of end windings 7, 8 are known per se, further explanations are unnecessary

to.

The stator also has at least one first coolant channel 9 . The coolant channel 9 is used to hold a cooling fluid, in particular a cooling liquid,

which flows through the coolant channel 9 to cool the stator 1 .

The coolant channel 9 has at least one coolant inlet 10 and at least

a coolant outlet 11 . Depending on the version, the scope of the

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11 be arranged.

The at least one coolant channel 9 is formed or arranged in a, in particular cylindrical, housing 12 of the stator 1 . The at least one coolant inlet 10 and the at least one coolant outlet 11 are also in or on

Housing 12 of the stator 1 arranged.

It is now provided that the at least one coolant channel 9 is arranged around one of the winding heads 7 or 8 so that the respective winding head 7 or 8 is arranged entirely in the coolant channel 9 . The coolant channel 9 is thus arranged at an axial end of the laminated core 22 . In particular, the at least one coolant channel 9 is designed as an annular channel. The coolant channel 9 is arranged in particular in such a way that it does not impede the rotor of the electrical machine. It can therefore be arranged or designed in such a way that it does not protrude beyond the laminated core 22 in the radial direction 3, although at least it does

on a radial outer side 13 of the laminated core 22 is possible.

The conductor ends 6 protrude directly into the at least one coolant channel 9 . This means that the coolant flows directly (immediately) around them. Directly means that there are no other partitions, etc., which could

terenden 6 separate from the coolant.

The housing 12 can be made in one or more parts in the area of the coolant channel 9

be guided.

For example, the housing 12 can be provided in this area with an annular groove for forming the coolant channel 9, as shown in the right-hand part of FIG. However, the coolant channel 9 can also be arranged in a cover 14, as is shown in the left-hand part of FIG. The cover 14 is connected to the rest of the housing 12 in particular in a liquid-tight manner. It

It is also possible for the housing 12 to have such a cover 14 on both sides

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which serve as a bearing for a rotor shaft 15 of the rotor. The housing 12 can also have a different division.

In the embodiment variant of the stator 1 shown in FIG. 1 , the first end winding 7 is arranged in the first coolant channel 9 and the second end winding 8 is arranged in a further coolant channel 16 . However, it should be pointed out once again that the electric machine or the stator 1 can also have only one coolant channel 9 for cooling only one of the two end windings 7.8, although the embodiment according to FIG. 1 with the coolant channel 9 and

the further coolant channel 16 is the preferred one.

The further coolant channel 16 can be designed in accordance with the coolant channel 9 . Accordingly, the statements on the coolant channel 9

also be transferred to the other coolant channel 16.

It should also be noted that the housing 12 has been described as part of the stator 1 in the above description. From another point of view, the housing 12 can also be associated with the electric machine, in which the stator 1 and the rotor are arranged. However, this consideration does not change the functional composition of the components. If the housing 12 is considered part of the stator 1, the electrical machine does not have to

teres housing have more, although this is possible.

In the embodiment variant shown in FIG. 1, the coolant channel 9 and the additional coolant channel 16 are independent of one another. Thus, the coolant channel 9 and the additional coolant channel 16 each have at least one coolant inlet 10 and at least one coolant outlet 11 . The speeds through which the coolant flows through the coolant channel 9 and the additional coolant channel 16 can therefore be different or the same. It is also possible that the coolant channel 9 and the additional coolant channel 16 of

different coolants are flown through.

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According to another embodiment variant, however, there is also the possibility that the coolant channel 9 and the further coolant channel 16 are flow-connected to one another. To make this clearer, a flow connection 17 is shown in dashed lines in FIG. The at least one flow connection 17 between the coolant channel 9 and the additional coolant channel 16

can be formed or arranged in or on a housing jacket 18 .

In principle, it is also possible in this embodiment variant that the coolant channel 9 and the further coolant channel 16 each have at least one coolant inlet 10 and at least one coolant outlet 11 of their own despite the at least one flow connection 17 . In this embodiment variant, however, according to a further embodiment variant it can also be provided that the coolant channel 9 and the further coolant channel 16 have a common coolant inlet

let 10 and have a common coolant outlet 11 .

This common coolant inlet 10 and coolant outlet 11 can be formed or arranged in separate areas in or on the housing 12 . For example, the coolant inlet 10 can be assigned to the coolant channel 9 and the coolant outlet 11 to the additional coolant channel 16 . It is also possible for both the coolant inlet 10 and the coolant outlet 11 to be assigned to the coolant channel 9 or to the additional coolant channel 16 . In this case, they can be positioned along the housing jacket 18 at different

chen points of the jacket circumference can be arranged.

According to a variant of this, however, provision can also be made for the coolant inlet 10 and the coolant outlet 11 to be arranged in a common connection element 19, as illustrated by the detail from the stator 1 in FIG. For separation purposes, the connecting element 12, like the coolant channel 9 and the additional coolant channel 16, can be provided with a partition 23, which has one or more openings in predeterminable areas to allow the coolant to pass between the “inlet channel” and the

To allow "exhaust channel".

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Such an embodiment of the common connection element 19 is also possible in the embodiment variant of the stator 1 in which the coolant channel 9 and the additional coolant channel 16 are separated from one another and each have a separate

Genetic coolant inlet 10 and its own coolant outlet 11 have.

The connecting element 19 can be formed in the housing 12 or on the body

housing 12 can be arranged.

For the sake of completeness, it should be noted that fluid lines are formed or arranged in or on the housing 12 which connect the coolant channel 9 and the additional coolant channel 16 that may be present to the respective coolant inlet 10 and coolant outlet 11 . The fluid lines can be designed as recesses in or openings through the housing 12 . But they can also be designed as pipes or hoses. the latter

can also apply to the at least one flow connection 17.

The cooling of the stator 1 can only take place at the conductor ends 6 of the electrical conductors 5 in the first and/or second end winding 7, 8 via the coolant channel.

nal 9 and / or the other coolant channel 16 take place.

According to another embodiment variant, the stator 1 can be additionally cooled via the slots 4 . For this purpose, at least one additional coolant channel can be formed in the grooves 4 instead of an electrical conductor 5 or in addition to the existing electrical conductors 5 . For example, instead of the second electrical conductor 5 in the radial direction 3 from the inside to the outside in FIG. The coolant

telkanal 9 and the other coolant channel 16 also flow-connected.

The at least one additional coolant channel in the grooves 4 can also be

Be arranged in another area within the grooves 4.

The procedure is that the grooves 4 in the axial direction 2 then respectively

at least one closing element 24 plate-shaped, in particular ring-shaped,

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preferably plate-shaped closing element 24 is arranged. The closing element 24 can be arranged directly adjacent to the laminated core 22 . The final element 24 has openings through which the conductor ends 6 of

electrical conductors 5 are guided.

Several terminating elements can be placed directly one above the other in the axial direction 2

elements 24 can be arranged.

The terminating elements 24 are connected to the laminated core 22 via a sealing element 20, as can be better seen in FIG. 3, which shows a section of the stator 1 in the region of the terminating elements 24. In particular, the closing elements 24 are glued to the end faces of the laminated core 22 via the sealing elements 20, so that the sealing elements 20 can therefore consist of an adhesive. The sealing elements 20 can also be formed by or consist of the synthetic resin with which the grooves 4 are filled,

after the electrical conductors 4 have been placed therein.

The connection between the terminating elements 24 and the component forming the grooves 4, in particular the laminated core 22, can alternatively or additionally be designed differently, for example positively, e.g. via optionally undercut grooves in the terminating elements 24, into which the

Sealing elements 20 protrude.

The closing elements 24 comprise a material that is not conductive to electrical current, in particular made of a plastic or consist of it. For example, the end elements 24 consist of a polyamide. In general, however, they can also have or consist of another non-conductive thermoplastic or duroplastic polymeric plastic. The closing elements preferably comprise or consist of a thermoplastic or duroplastic polymeric plastic which has a temperature resistance of at least 80.degree. C., preferably at least 100.degree. What is meant by this is that at these minimum temperatures the plastic does not soften to the extent

that the closing elements 24 lose their shape.

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According to one embodiment variant, it is also possible for the closing elements 24 to be formed from a composite material which has a carrier made from a first material on which a comparatively softer material is arranged. For example, the softer material may be an elastomer disposed on and bonded to the backing. The elastomer can, for example, be a natural rubber, a styrene-butadiene rubber, an optionally car

boxylated nitrile rubber or a thermoplastic elastomer, etc.

This softer material of the composite material can be arranged immediately after the harder material and immediately after the laminated core 22 in the radial direction 3 . As an alternative or in addition to this, the softer material can also be arranged in the axial direction 2 between the laminated core 22 and the harder material of the closing element 24, as shown in broken lines in FIG. In all of these configurations, it is possible for the softer material to be arranged at least partially in a recess in the harder material of the closing element 24 . Furthermore, the softer material can form its own molded body, which is connected to the comparatively harder material, for example glued. For example, the softer material can be an elastomeric ring. But it is also possible that the softer

material is sprayed directly onto the hard material, etc.

The closing elements 24 can only consist of the carrier, which can be a fiber-reinforced plastic, for example a glass-fiber-reinforced polyphenylene sulfide. Other fiber materials and/or other polymeric plastics (corresponding to the above statements on the plastics) can also be used. The materials mentioned can also be used with the

be combined with a softer material at the same time.

It is provided that the sealing elements 20 are adhesively connected to the laminated core 22 of the stator 1, in particular glued, with the sealing elements 20 being

optionally can form the adhesive itself.

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In addition to the described front-side sealing of the grooves 4, a groove seal can also be provided to seal the grooves 4 in their axial course. This can be provided at least in the area adjoining the coolant channel 9 and the additional coolant channel 16 , preferably along the entire course in the axial direction 2 . For example, impregnation (with an impregnating agent) can be used for this purpose. The impregnation means that the grooves 4 are no longer wetted by the coolant. Accordingly, the impregnation agent depends on the coolant used. Water or an oil, for example, can be used as a coolant. The impregnating agent can be, for example, a one-component resin, such as epoxy resins, (unsaturated) polyesterimides, silicones, alkyd resins. A resin or a casting compound can also be used as impregnation, with which the free volume between the electrical conductors 5 and/or in the area of the radial

len groove opening is filled.

The slot seal can also be formed by so-called slot wedges. These are elements which, viewed in cross-section, can be designed, for example, in the shape of a trapezoid, and which are inserted into the grooves 4 or attached thereto.

to be sorted.

It is also possible to form the additional groove seal with a further sealing element. The further sealing element can, for example, be a paper that is impregnated with an impregnating agent. The impregnation prevents

the wetting of the paper with the coolant.

The additional slot seal allows the air gap between the stator 1 and the rotor of the electrical machine arranged therein to be sealed.

the.

If the stator 1 or the electrical machine provided with it is cooled exclusively in the end windings 7 and/or 8, the coolant channel 9 and the further coolant channel 16 must be sealed mainly only at the

th 4 done because the coolant channel 9 and the other coolant channel 16 as

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(Annular) grooves in the housing 12 and the cover 14 can be performed. However, this groove-shaped design of the coolant channel 9 and the further coolant channel 16 in the housing 12 also has an effect in the version with the additional

chen groove cooling the advantage of reducing the sealing surfaces.

The stator 1 described can only be cooled in the area of the first and second end windings 7 , 8 . A direct groove cooling can be provided if necessary. However, it is possible that the electrical machine itself has a further cooling, but not the direct cooling

electrical conductor 5 is used.

The casting of the grooves 5 is preferably carried out using the full casting method, but this can also be done in a different way. In the case of the full encapsulation method, the laminated core provided with the electrical conductors 5 is placed in an encapsulation tool. The casting compound, i.e. in particular a synthetic resin, is filled into the middle of the stator, among other things, and then pushed into the slots 4 by inserting a core rod into the middle of the stator. In order to fill the grooves 4 without pores, a low-viscosity, degassed casting compound is preferably used. In addition or as an alternative to this, the method for further reducing air inclusions can also be carried out under vacuum, for which purpose the casting tool is placed in a corresponding

Device for evacuation can be given.

In order to be able to produce the additional coolant channels for the slot cooling at the same time as the slots 4 are filled with the casting compound, shaped rods or shaped tubes or correspondingly shaped cores (generally also referred to as placeholders) can be inserted into the slots 4, which after the slots have been filled 4 can be removed again with the casting compound 4 as soon as the casting compound 4 has the necessary strength to do so. The shaped rods 4 or shaped tubes or cores can consist, for example, of polytetrafluoroethylene or

have such a coating.

However, the additional coolant channels can also be formed by tubes which are arranged in the grooves 4 and which after the casting of the grooves 4 in

the grooves 4 remain.

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According to one embodiment variant of the cooling, it can be provided that a coolant is used for the cooling that has a dynamic viscosity at 20° C. of at least 0.01 kg/m.s. In particular, the coolant can have a dynamic viscosity at 20° C. between 0.01 kg/m.s and 0.07 kg/m.s. This coolant can be, for example, a gear oil such as Shell L12108, Pentosin FFL, or a heat transfer fluid such as Syltherm 800, Galden HAT 230, Shell HeatTransfer S2.

According to a further embodiment variant, it can be provided that a pressure difference of the conveying pressure of the coolant between the input side and the output side of the coolant channel or coolant channels is between 0.2

bar and 2 bar, in particular between 0.4 bar and 1.5 bar.

The exemplary embodiments show or describe possible variants, with combinations of the individual variants among one another.

that are possible.

Finally, for the sake of order, it should be pointed out that, for a better understanding of the structure, the stator 1 or the electrical machine does not necessarily

are shown to scale by gender.

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17

Reference List

Stator axial direction radial direction slot

director

End of conductor Winding head Winding head Coolant duct Coolant inlet Coolant outlet Housing outside Cover Rotor shaft Coolant duct Flow connection Housing jacket Connection element Sealing element Circumferential direction of laminated core partition

final element

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Claims (16)

patent claims 1. Stator (1) for an electrical machine, with a plurality of slots (4), in each of which at least one electrical conductor (5) is arranged, the electrical conductors (5) having conductor ends (6) which the slots (4) protrude in an axial direction (2), and which form a first end winding (7) and a second end winding (8), and with a coolant channel (9) which has a coolant inlet (10) and a coolant outlet (11), the coolant channel (9) is arranged to run around at least one of the first or the second winding overhang (7, 8), and wherein in the axial direction (2) a terminating element (24) is arranged adjoining the grooves (4) through which the conductor ends (5) project through, characterized in that the grooves (4) are each sealed with at least one sealing element (20), and that the closing elements (24) are connected via the sealing elements (20) to the component forming the grooves (4). are bound. 2. Stator (1) according to claim 1, characterized in that the coolant channel (9) is arranged around the first end winding (7) and a further cooling central channel (16) is arranged around the second end winding (8). 3. Stator (1) according to claim 2, characterized in that the coolant channel (9) and the further coolant channel (16) each have at least one coolant have teleinlet (10) and at least one coolant outlet (11). 4. Stator (1) according to claim 2, characterized in that the coolant channel (9) and the further coolant channel (16) flow-connected to each other are. 5. Stator (1) according to claim 4, characterized in that the coolant channel (9) and the further coolant channel (16) have a common coolant inlet (10) and a common coolant outlet (11). N2020/32300-AT-00 6. Stator (1) according to any one of claims 3 to 5, characterized in that the coolant inlet (10) and the coolant outlet (11) in a common men connecting element (19) are arranged. 7. Stator (1) according to any one of claims 1 to 6, characterized in that that the closing elements (24) are formed from a composite material. 8. Stator (1) according to claim 7, characterized in that the composite material of the closing elements (24) is formed from a combination of a hard material and a comparatively softer material, which optionally forms the sealing elements (20). 9. Stator (1) according to any one of claims 1 to 8, characterized in that the grooves (4) ver- in the axial course with an additional groove seal see are. 10. Stator (1) according to claim 9, characterized in that as the additional groove seal as an impregnation or as an optionally wedge-shaped Sealing elements is formed. 11. Stator (1) according to claim 10, characterized in that the sealing telemente are designed as impregnated papers. 12. Stator (1) according to any one of claims 1 to 11, characterized in that in the grooves (4) at least one additional coolant channel is formed is. 13. Electrical machine comprising a stator (1), characterized characterized in that the stator (1) is designed according to one of claims 1 to 12. N2020/32300-AT-00 14. A method for cooling a stator (1) for an electrical machine, in which a plurality of slots (4) are formed, in each of which at least one electrical conductor (5) is arranged, the electrical conductors (5) having conductor ends (6) are formed, which are arranged projecting beyond the slots (4) in an axial direction (2), and with which a first end winding (7) and a second end winding (8) are formed, and wherein in the stator (1) a coolant channel (9 ) is formed with a coolant inlet (10) and a coolant outlet (11) which is formed to extend around at least one of the first or the second end winding (7, 8), and wherein in the axial direction (2) to the grooves (4) then in each case a closing element (24) is arranged, through which the conductor ends (5) are arranged projecting, characterized in that the grooves (4) are each sealed with a sealing element, and that the closing elements (24) via the sealing elements te (20) with which the grooves (4) forming component are connected. 15. The method according to claim 14, characterized in that a coolant is used for the cooling, which has a dynamic viscosity at 20 ° C of at least 0.01 kg/m.s. 16. The method according to claim 14 or 15, characterized in that a pressure difference of the delivery pressure of the coolant between the input side and the output side of the coolant channel or coolant channels between between 0.2 bar and 2 bar. N2020/32300-AT-00