COOLING DEVICE FOR AN ELECTRIC DRIVE TRAIN COMPONENT, ELECTRIC DRIVE TRAIN ASSEMBLY, METHOD FOR OPERATING A COOLING DEVICE, METHOD FOR COOLING AN ELECTRIC DRIVE TRAIN COMPONENT, AND VEHICLE

Abstract

A cooling device for an electric drive train component can comprise a coolant inlet port configured to receive gaseous coolant from the electric drive train component, a coolant outlet port configured to deliver liquid coolant to the electric drive train component, a heat exchanger configured to extract heat from the gaseous coolant such that the gaseous coolant is at least partially transformed into liquid coolant, wherein the heat exchanger is fluidically connected to the coolant inlet port and the coolant outlet port such that the heat exchanger is arranged between the coolant inlet port and the coolant outlet port along a coolant flow direction, and a coolant collection channel fluidically connected to the heat exchanger and the coolant outlet port such that the coolant collection channel is arranged between the heat exchanger and the coolant outlet port along the coolant flow direction.

Claims

1. A cooling device for an electric drive train component, comprising: a coolant inlet port configured to receive gaseous coolant from the electric drive train component; a coolant outlet port configured to deliver liquid coolant to the electric drive train component; a heat exchanger configured to extract heat from the gaseous coolant such that the gaseous coolant is at least partially transformed into liquid coolant, wherein the heat exchanger is fluidically connected to the coolant inlet port and the coolant outlet port such that the heat exchanger is arranged between the coolant inlet port and the coolant outlet port along a coolant flow direction; and a coolant collection channel fluidically connected to the heat exchanger and the coolant outlet port such that the coolant collection channel is arranged between the heat exchanger and the coolant outlet port along the coolant flow direction, wherein an end of the coolant collection channel arranged adjacent to the coolant outlet port is located on a lower vertical level than the heat exchanger in an operational position of the cooling device.

2. The cooling device of claim 1, wherein the coolant collection channel is arranged below the heat exchanger in the operational position of the cooling device.

3. The cooling device of claim 1, wherein a cross section of at least a portion of the coolant collection channel decreases along the coolant flow direction or is substantially constant along the coolant flow direction.

4. The cooling device of claim 3, wherein the cross section decreases continuously.

5. The cooling device of claim 1, wherein the heat exchanger is a gas-to-gas heat exchanger configured to deliver heat to ambient air.

6. The cooling device of claim 1, further comprising: a reservoir comprising a heat absorption liquid, wherein the heat exchanger is a gas-to-liquid heat exchanger being thermally coupled to the reservoir.

7. The cooling device of claim 1, further comprising: a coolant comprising a water-based coolant.

8. An electric drive train assembly comprising: a cooling device for an electric drive train component, wherein the cooling device comprises: a coolant inlet port configured to receive gaseous coolant from the electric drive train component, a coolant outlet port configured to deliver liquid coolant to the electric drive train component, a heat exchanger configured to extract heat from the gaseous coolant such that the gaseous coolant is at least partially transformed into liquid coolant, wherein the heat exchanger is fluidically connected to the coolant inlet port and the coolant outlet port such that the heat exchanger is arranged between the coolant inlet port and the coolant outlet port along a coolant flow direction, and a coolant collection channel fluidically connected to the heat exchanger and the coolant outlet port such that the coolant collection channel is arranged between the heat exchanger and the coolant outlet port along the coolant flow direction, wherein an end of the coolant collection channel arranged adjacent to the coolant outlet port is located on a lower vertical level than the heat exchanger in an operational position of the cooling device; and an electric machine, wherein the electric machine comprises: a coolant circulation channel system fluidically connected to the coolant inlet port and to the coolant outlet port of the cooling device.

9. The electric drive train assembly of claim 8, wherein at least a portion of at least one of the coolant collection channel or the heat exchanger is at least partially integrated into the electric machine.

10. The electric drive train assembly of claim 8, further comprising: a transmission drivingly connected to the electric machine, wherein the transmission comprises the coolant circulation channel system fluidically connected to the coolant inlet port and to the coolant outlet port of the cooling device.

11. The electric drive train assembly of claim 10, further comprising: a further heat exchanger fluidically interposed between the transmission and the electric machine.

12. The electric drive train assembly of claim 8, wherein the electric drive train assembly is comprised in a vehicle.

13. The electric drive train assembly of claim 8, wherein the coolant collection channel is arranged below the heat exchanger in the operational position of the cooling device.

14. The electric drive train assembly of claim 8, wherein a cross section of at least a portion of the coolant collection channel decreases along the coolant flow direction or is substantially constant along the coolant flow direction.

15. The electric drive train assembly of claim 14, wherein the cross section decreases continuously.

16. The electric drive train assembly of claim 8, wherein the heat exchanger is a gas-to-gas heat exchanger configured to deliver heat to ambient air.

17. A method for operating a cooling device for an electric drive train component, comprising: receiving gaseous coolant from the electric drive train component; transforming at least a portion of the gaseous coolant into liquid coolant; and collecting the liquid coolant in a coolant collection channel having an end being arranged adjacent to a coolant outlet port which is located on a lower vertical level than a heat exchanger and providing the liquid coolant to the electric drive train component.

18. The method of claim 17, wherein the coolant is a water-based coolant.

19. A method for cooling an electric drive train component, comprising: transforming at least a portion of liquid coolant into gaseous coolant by absorbing heat from the electric drive train component; providing the gaseous coolant to a cooling device; receiving gaseous coolant from the electric drive train component; transforming at least a portion of the gaseous coolant into liquid coolant; collecting the liquid coolant in a coolant collection channel having an end being arranged adjacent to a coolant outlet port which is located on a lower vertical level than a heat exchanger and providing the liquid coolant to the electric drive train component; and receiving liquid coolant from the cooling device.

20. The method of claim 19, wherein the coolant is a water-based coolant.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0043] FIG. 1 shows a vehicle according to the present disclosure with an electric drive train assembly according to the present disclosure, wherein the electric drive train assembly comprises a cooling device according to the present disclosure and wherein an electric drive train component of the electric drive train assembly can be cooled using a method according to the present disclosure.

[0044] FIG. 2 shows the electric drive train assembly of FIG. 1 in a more detailed view.

[0045] FIG. 3 shows the cooling device of FIGS. 1 and 2 according to a first example, wherein the cooling device and an electric machine are integrated.

[0046] FIG. 4 shows the cooling device of FIGS. 1 and 2 according to a second example, wherein the cooling device and an electric machine are integrated.

[0047] FIG. 5 shows the cooling device of FIGS. 1 and 2 according to a third example, wherein the cooling device and an electric machine are integrated.

[0048] FIG. 6 shows an alternative cooling device and an electric machine, wherein the cooling device and the electric machine are not integrated.

DETAILED DESCRIPTION

[0049] The Figures are merely schematic representations and serve only to illustrate examples of the disclosure. Identical or equivalent elements are in principle provided with the same reference signs.

[0050] FIG. 1 shows an electric vehicle 10 comprising an electric drivetrain assembly 12.

[0051] The electric drivetrain assembly comprises 12 a battery unit 14, an inverter unit 16, an electric machine 18, and a transmission 20. More generally speaking, each of the battery unit 14, the inverter unit 16, the electric machine 18, and the transmission 20 may be called an electric drive train component 21.

[0052] The electric drivetrain assembly 12 is configured to drive the rear wheels 22 of the vehicle 10.

[0053] To this end, the battery unit 14 is electrically connected to the electric machine 18 via the inverter unit 16. The electric machine 18 is drivingly coupled to the rear wheels 22 via the transmission 20.

[0054] The electric drivetrain assembly 12 is represented in more detail in FIG. 2.

[0055] In this representation, also components of a cooling system of the electric drivetrain assembly 12 are visible.

[0056] In this context, the electric drivetrain assembly 12 comprises a cooling device 24 which is integrated with the electric machine 18. The cooling device 24 comprises a heat exchanger 26 which in the present example is a gas-to-gas heat exchanger, i.e., a heat exchanger that is configured to transfer heat between a gaseous coolant of the cooling system and ambient air.

[0057] Moreover, the electric drivetrain assembly 12 comprises a pump 28 and a further heat exchanger 30.

[0058] In the example shown in FIG. 2, the pump 28 and the further heat exchanger 30 form part of the transmission 20. Consequently, in order to better distinguish the heat exchangers 26, 30, the further heat exchanger 30 may also be designated as a transmission heat exchanger.

[0059] The electric machine 18 comprises a coolant circulation channel system C1 along which coolant may circulate through the electric machine 18.

[0060] The coolant circulation channel system C1 is connected to a coolant inlet port 32 and a coolant outlet port 34 of the cooling device 24.

[0061] Also, the transmission 20 comprises a coolant circulation channel system C2 along which coolant may circulate through the transmission 20.

[0062] The coolant circulation channel system C2 of the transmission 20 is also fluidically connected to the coolant inlet port 32 and the coolant outlet port 34 of the cooling device 24. This is done via the electric machine 18, more precisely via the coolant circulation channel system C1 of the electric machine 18.

[0063] Thus, along the flow direction F of the coolant circulating in coolant circulation channel system C1 and coolant circulation channel system C2, the further heat exchanger or transmission heat exchanger 30 is fluidically interposed between the transmission 20 and the electric machine 18.

[0064] FIG. 3 shows a first example of the cooling device 24. The cooling device 24 is represented in its operational position. In this example, the cooling device 24 and the electric machine 18 are integrated. In the present context, this means that the components of the electric machine 18 and the components of the cooling device 24 are arranged in a common housing.

[0065] In FIG. 3, a rotor R and stator windings W of the electric machine 18 are visible.

[0066] Portions of the coolant circulation channel system C1 extend through the stator windings W. Four exemplary portions are shown and designated by C1a, C1b, C1c and C1d respectively.

[0067] Since the cooling device 24 is integrated with the electric machine 18, the coolant inlet port 32 and the coolant outlet port 34 are formed as cross-sections being arranged at the system boundary. As will be explained in more detail further below, the coolant inlet port 32 is configured to receive gaseous coolant. The coolant outlet port 34 is configured to deliver liquid coolant.

[0068] The heat exchanger 26 is, thus, configured to extract heat from the gaseous coolant such that the gaseous coolant is at least partially transformed into liquid coolant. In other words, the heat exchanger 26 is configured to condense coolant.

[0069] As has already been mentioned before, the heat exchanger 26 is a gas-to-gas heat exchanger being configured to deliver heat to ambient air.

[0070] In the example of FIG. 3, the cooling device 24 additionally comprises a recirculation port 36 which is fluidically connected to the circulation channel system C1 of the electric machine 18.

[0071] The coolant inlet port 32 is fluidically connected to the heat exchanger 26 via a channel segment 38.

[0072] In the present example, the first channel segment 38 is oriented vertically, whereas the heat exchanger 26 is arranged at a top end of the first channel segment 38.

[0073] The heat exchanger 26 is also fluidically connected to the coolant outlet port 34 and the recirculation port 36. To this end, a coolant collection channel 40 is fluidically interposed between the heat exchanger 26, the coolant outlet port 34 and the recirculation port 36.

[0074] In the example of FIG. 3, the coolant collection channel 40 is arranged below the heat exchanger 26.

[0075] A cross section of the coolant collection channel is substantially constant along the coolant flow direction F.

[0076] Moreover, the coolant collection channel 40 has an end being arranged adjacent to the coolant outlet port 34, i.e., remote from the heat exchanger 26. This end is arranged at a lower vertical level as the heat exchanger 26.

[0077] In the present example, the coolant collection channel 40 extends in a vertical direction.

[0078] In the example of FIG. 3, a water-based coolant is used and the cooling system relies on a change of the state of aggregation of the coolant.

[0079] Consequently, for cooling the electric machine 18 or, more generally an electric drivetrain component, the following method may be carried out.

[0080] In a first step S1, at least a portion of liquid coolant is transformed into gaseous coolant by absorbing heat from the electric machine 18, more precisely from the stator windings W. This is illustrated by arrow's carrying the reference sign L entering the stator windings W and arrows carrying the reference sign G exiting the stator windings W.

[0081] The portions of the liquid coolant L which are not gasified are indicated by arrows carrying the reference sign L exiting the stator windings W.

[0082] Thus, the coolant performs a change of the state of aggregation.

[0083] At the same time, a temperature of the coolant is increased due to the fact that it absorbs heat from the stator windings W.

[0084] Subsequently, in a second step, the gaseous coolant is provided to the cooling device 24 via the coolant inlet port 32.

[0085] It is noted that the gaseous coolant G is warm or hot and therefore has the tendency to climb up in a vertical direction.

[0086] The liquid coolant L exiting the stator windings W is denser than the gaseous coolant and therefore will not climb towards the coolant inlet port 32.

[0087] In a third step S3, the cooling device 24 is operated.

[0088] This means that the gaseous coolant G is received and transformed into liquid coolant using the heat exchanger 26.

[0089] In this context, the heat exchanger 26 transfers heat from the gaseous coolant G to ambient air.

[0090] At the same time, by transferring heat from the coolant to ambient air, the temperature of the coolant is reduced.

[0091] This is represented by an arrow being equipped with reference sign G entering the heat exchanger 26 and an arrow carrying reference sign L exiting the heat exchanger 26.

[0092] Since the transformation into the liquid state may be incomplete, also an arrow carrying reference signs G is shown in FIG. 3. This arrow represents coolant in gaseous form leaving the heat exchanger 26.

[0093] Both liquid coolant L and gaseous coolant G leaving the heat exchanger 26 are collected in the coolant collection channel 40. Due to the fact that the coolant exiting the heat exchanger 26 is in a liquid state and/or of a relatively cold temperature, the coolant falls vertically down.

[0094] This creates a suction effect driving additional gaseous coolant G into the heat exchanger 26.

[0095] In the present example, the coolant exiting the heat exchanger 26 in gaseous form is fed back to the electric machine 18 via the recirculation port 36. The coolant being in the liquid state leaves the cooling device 24 via the coolant outlet port 34. Thereby, liquid coolant L is provided to the electric machine 18 which can again be used to absorb heat inside the stator windings W.

It is noted that the features of step S3 may also be summarized as a method for operating a cooling device 24.

[0096] FIG. 4 shows a second example of the cooling device 24. The cooling device 24 is represented in its operational position. Also in this example, the cooling device 24 and the electric machine 18 are integrated. In the present context, this means that the components of the electric machine 18 and the components of the cooling device 24 are arranged in a common housing.

[0097] In the following, only the differences with respect to the example of FIG. 3 will be explained. Same or corresponding parts will be designated with the same reference signs.

[0098] The first difference between the examples of FIGS. 3 and 4 is that a cross-section of the coolant collection channel 40 decreases along the coolant flow direction F in the example of FIG. 4. More precisely, the cross section of the coolant collection channel 40 decreases continuously. In other words, the coolant collection channel 40 is funnel-shaped.

[0099] A further difference lies in the fact that no recirculation port is provided in the example of FIG. 4.

[0100] Beyond that, especially as far as the methods are concerned, reference is made to the explanations provided in connection with FIG. 3.

[0101] FIG. 5 shows a third example of the cooling device 24. The cooling device 24 is represented in its operational position. Also in this example, the cooling device 24 and the electric machine 18 are integrated. In the present context, this means that the components of the electric machine 18 and the components of the cooling device 24 are arranged in a common housing.

[0102] Again, only the differences with respect to the examples which have already been explained above, will be mentioned.

[0103] The example of FIG. 5 is a variant of the example of FIG. 3.

[0104] A difference lies in that the cooling device 24 now comprises a reservoir 42 with a heat absorption liquid A arranged therein. The heat exchanger 26 is a gas-to-liquid heat exchanger.

[0105] This means, that heat being extracted from the gaseous coolant G by using the heat exchanger 26 is not transferred to ambient air anymore, but to the heat absorption liquid A being arranged in the reservoir 42. To this end, the heat exchanger 26 is thermally coupled to the reservoir 42.

[0106] Beyond that, reference is made to the above explanations.

[0107] FIG. 6 shows a fourth example of the cooling device 24. The cooling device 24 is again represented in its operational position. As before, only the differences over the examples as explained above will be mentioned.

[0108] In contrast to the above examples, the cooling device 24 is separate, i.e., not integrated, from the electric machine 18.

[0109] In this alternative, the coolant inlet port 32 and the coolant outlet port 34 are formed as connection points for a piping P or hoses which. The electric machine 18 and the cooling device 24 are fluidically connected via the piping P or hoses.

[0110] Other variations to the disclosed examples can be understood and effected by those skilled in the art in practicing the claimed disclosure, from the study of the drawings, the disclosure, and the appended claims. In the claims the word comprising does not exclude other elements or steps and the indefinite article a or an does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope of the claims.

LIST OF REFERENCE SIGNS

[0111] 10 vehicle [0112] 12 electric drivetrain assembly [0113] 14 battery unit [0114] 16 inverter unit [0115] 18 electric machine [0116] 20 transmission [0117] 21 electric drive train component [0118] 22 rear wheels [0119] 24 cooling device [0120] 26 heat exchanger [0121] 28 pump [0122] 30 further heat exchanger [0123] 32 coolant inlet port [0124] 34 coolant outlet port [0125] 36 recirculation port [0126] 38 channel segment [0127] 40 coolant collection channel [0128] A heat absorption liquid [0129] C1 coolant circulation channel system of the electric machine [0130] C2 coolant circulation channel system of the transmission [0131] F coolant flow direction [0132] G gaseous coolant [0133] L liquid coolant [0134] P piping [0135] R rotor of the electric machine [0136] W stator windings of the electric machine