Cooling system for drive device of hybrid or electric vehicle, and drive device having such cooling system

Abstract

The invention relates to a cooling system for a drive of a hybrid or electric vehicle and to a drive having such a cooling system. The cooling system comprises a storage device (120) which is designed to receive and provide a fluid of a first coolant circuit which is transported from the bottom shell (130) by means of a pump (125) into an interior space (135) of a housing (140) of the storage device (120), at least one coolant line (180) of a second coolant circuit being arranged on and / or in the housing (140), the at least one coolant line (180) is designed to conduct coolant from the power electronics (175) to the heat exchanger (185).

Description

Technical Field

[0001] The present invention relates to a cooling system for a drive device of a hybrid vehicle or an electric vehicle, and a drive device having such a cooling system. Background Art

[0002] A hybrid vehicle or electric vehicle driven via an electric axle usually has an electric motor, power electronics and optionally a transmission, which are all cooled via a heat exchanger. The cooling system for the electric axle can have at least one first coolant circuit, which is generally configured to cool the transmission of the hybrid vehicle or electric vehicle and the rotor of the electric motor. A second coolant circuit can also be provided, which is configured to cool the power electronics of the hybrid vehicle or electric vehicle and the stator of the electric motor. The cooling of the power electronics is usually carried out actively via a plate cooler. A plate cooler is a special structural form of a heat exchanger, which is usually composed of corrugated, shaped plates, which are combined so that the medium to be heated and then releases heat flows in consecutive gaps.

[0003] DE 10 2018 213 394 A1 discloses a cooling device for an electric axle, the cooling device having: a first coolant circuit, the first coolant circuit being configured to cool a transmission mechanism of a hybrid vehicle or an electric vehicle and a rotor of an electric motor; and a second coolant circuit, the second coolant circuit being configured to cool an inverter of an electric axle of a hybrid vehicle or an electric vehicle and a stator of an electric motor. At least one temperature sensor is provided, the temperature sensor being configured to measure the temperature of the transmission mechanism, the temperature of the rotor of the electric motor of a hybrid vehicle or an electric vehicle, the temperature of the inverter of the electric axle or the temperature of the stator of the electric motor of a hybrid vehicle or an electric vehicle. In addition, a pumping assembly driven by an electric motor is provided, the pumping assembly having a first pump and a second pump connected by a common shaft. The first pump is configured to generate a coolant volume flow of the first coolant circuit, and the second pump is configured to generate a coolant volume flow of the second coolant circuit. The electric motor can be controlled by using a temperature detected according to at least one temperature sensor. Summary of the invention

[0004] The object of the present invention is to provide a cooling system for a drive device with improved cooling performance. The invention achieves this object by means of the subject matter of the independent claims. The dependent claims reflect preferred embodiments.

[0005] The cooling system for a drive device of a hybrid vehicle or electric vehicle according to the invention comprises a reservoir device, which is designed to receive and provide a fluid of a first coolant circuit, the fluid of the first coolant circuit being conveyed from a sump by means of a pump into an interior space of a housing of the reservoir device, wherein at least one coolant line of a second coolant circuit is arranged on and / or in the housing, the at least one coolant line being designed to conduct coolant from a power electronic device to a heat exchanger. The interior space is at least partially spatially delimited by the housing of the reservoir device, wherein the interior space is designed such that a sufficient amount of fluid can be received in the reservoir device and can be stored, for example, for supply to heat consumers or other components.

[0006] The pump is part of the hydraulic system, is preferably designed as a vane pump and can be driven at least indirectly by an electric motor in order to draw the fluid of the first coolant circuit from the sump and convey it to a storage device. The storage device is in particular a dry sump storage container, which is also referred to as a tank or storage tank. If the fluid of the first coolant circuit is oil, the storage device is also understood to be an oil tank.

[0007] From the reservoir, fluid can be delivered to at least one further pump of the hydraulic system for cooling or lubricating heat consumers or other components of the motor vehicle. In other words, the heat consumers or other components are fed from the reservoir. The further pump can be implemented in a co-driven manner together with the pump that delivers the fluid from the sump to the reservoir by the mentioned electric motor. Thus, at least two pumps can be operatively connected to a common drive shaft. Alternatively, the further pump can be driven by a separate electric motor. After the heat consumers or components have been supplied with fluid from the first coolant circuit, the fluid is returned to the sump via suitable means and in a manner known in principle, from where the fluid can then be delivered to the reservoir again.

[0008] The storage device is formed by a housing which can be made in one piece or in multiple pieces. The material of the storage device or the material of the housing can be adapted to the requirements of the cooling system. It is conceivable that the housing is made of light metal in order to reduce the overall weight of the vehicle. Preferably, the storage device is made by casting.

[0009] By conveying the fluid from the bottom shell into the reservoir, a required fluid level is always maintained in the reservoir or in the interior of the housing in order to ensure that the heat consumers are adequately supplied at all times.

[0010] In one embodiment, at least one coolant line of the second coolant circuit extends at least in sections through the interior of the housing, more precisely in such a way that at least a portion of the outer circumferential side of the at least one coolant line is always in contact with the fluid in the interior of the housing. In this sense, in one embodiment, at least one coolant line is designed to be essentially tubular and is guided at least in sections through the interior of the housing, wherein the at least one coolant line is at least partially surrounded by the fluid of the first coolant circuit located in the interior of the housing. The coolant guided in the coolant line can thus absorb heat from the fluid present in the supply device and / or flowing into the supply device.

[0011] The first coolant circuit is configured to cool the transmission and the rotor of the electric machine of the hybrid vehicle or electric vehicle. In particular, when transmission parts such as gears, shafts or bearing elements are lubricated by the first coolant circuit, the first coolant circuit is also a lubricant circuit.

[0012] The second coolant circuit is configured to cool the power electronics of a hybrid vehicle or electric vehicle and the stator of the electric machine. The power electronics are part of a power module of the electric machine of a hybrid vehicle or electric vehicle and are configured to operate, control and regulate the electric machine. The power electronics may include an inverter or similar device that is cooled by the second coolant circuit.

[0013] At least one coolant line can be designed in the form of a channel in the form of a hose, a tube or the like. Preferably, at least one coolant line consists of a material, such as copper or aluminum, which allows the best possible heat transfer between the coolant of the second coolant circuit and the fluid of the first coolant circuit located in the supply device. For example, water or other known coolants are suitable as coolants. Therefore, when water is used as coolant, water cooling of the fluid of the first coolant circuit is carried out.

[0014] At least one coolant line is configured to be connected upstream to a plate cooler of the power electronics. After cooling the power electronics, the coolant is guided via the at least one coolant line to a heat exchanger, in which the fluid heated by the operation of the drive is cooled.

[0015] The heat exchanger or its structural size depends on the required cooling performance. By passing the coolant through the storage device, the fluid can release heat or be cooled in the interior of the housing, thereby making the heat exchanger correspondingly smaller than the known solutions.

[0016] It is conceivable to guide the at least one coolant line on the shortest route from one side wall of the housing through the interior of the housing to the opposite side wall. However, it is also possible that the at least one coolant line is designed in a spiral manner in order to increase the extent of the at least one coolant line through the interior of the housing. The extent of the coolant line can be selected, in particular, depending on the arrangement of the power electronics, the storage device and / or the heat exchanger on the vehicle.

[0017] One or more coolant lines can be guided at least in sections through the interior of the housing. Therefore, all descriptions about the at least one coolant line and about the further coolant lines which are also arranged at least in sections in the storage device are to be understood analogously and can be applied accordingly. Due to the coolant flowing through the storage device, the fluid of the first coolant circuit can release a portion of its heat in the storage device.

[0018] Preferably, an input line of the first coolant circuit is arranged on the storage device, and the input line is set up to connect the interior space of the housing with the pump. Via the input line, the fluid of the first coolant circuit is guided into the interior space of the housing by the pump. Therefore, the input line is understood as an inlet of the storage device. The input line can be a simple opening or opening on the housing of the storage device, which opens into the interior space of the housing at the upper side or lower side or side wall of the housing. Alternatively, the input line can be a pipe or a hose, which at least partially extends through the interior space of the housing and guides the fluid to the desired position in a desired manner.

[0019] In one embodiment, the input line is positioned and oriented relative to the at least one coolant line in such a way that the volume flow of the first coolant circuit is directed toward the at least one coolant line. In other words, the fluid of the first coolant circuit is directed and conveyed directly to the at least one coolant line via the input line, so that the volume flow impinges substantially directly on the at least one coolant line and thus forms turbulence on and around the at least one coolant line. Thus, a better heat transfer is achieved. Thus, by precisely positioning and orienting the input line on the housing and in the interior of the housing, a turbulent environment is generated around the at least one coolant line.

[0020] In an alternative embodiment, the input line is set up to accommodate at least one longitudinal section of at least one coolant line, wherein the inner diameter of the input line, at least in the region accommodating at least one coolant line, is greater than the outer diameter of at least one coolant line. Thus, a double-walled pipe section is realized on at least a portion of the longitudinal extension of at least one coolant line, in which at least one coolant line is surrounded by the fluid of the first coolant circuit in the input line, and in the double-walled pipe section, the fluid of the first coolant circuit guided through the input line is first guided along at least one coolant line and then enters the interior space of the housing of the storage device. Therefore, the fluid has been cooled inside the input line. The input line has an input end or an inlet and an output end or a discharge, wherein the input end faces the pump and the output end faces the interior space of the housing.

[0021] The inlet and outlet of the supply line are preferably arranged relative to the flow direction of the coolant through at least one coolant line in such a way that the fluid flows in the opposite direction to the coolant, thereby achieving a countercurrent flow, which further improves the heat transfer.

[0022] In a further development of the invention, the supply line is arranged coaxially with the at least one coolant line at least in the region accommodating the at least one coolant line. If both the supply line and the at least one coolant line have a circular cross section, the section of the at least one coolant line that is guided through the supply line will be surrounded uniformly by the fluid of the first coolant circuit over the entire surface, thereby achieving a uniform heat transfer between the fluid and the coolant.

[0023] The present invention includes the following technical teachings: at least one coolant circuit has a ridge, a depression, a projection and / or a recess on the side facing the fluid of the first coolant circuit, thereby increasing the contact area with the fluid of the first coolant circuit in the inner space of the housing. By increasing the contact area of ​​at least one coolant circuit, the heat transfer between the fluid of the first coolant circuit and the coolant of the second coolant circuit is improved, thereby allowing the heat exchanger and / or the plate cooler to be designed to be thinner or smaller. In one embodiment, at least one coolant circuit has cooling ribs, cooling plates and / or cooling fins on its surface in contact with the fluid of the first coolant circuit, which serves to increase the surface area of ​​at least one coolant circuit, thereby improving the cooling effect.

[0024] The elevations, depressions, projections and / or cutouts can be part of at least one coolant circuit or can be designed as a component separate from at least one coolant circuit, wherein the component is in any case connected to at least one coolant circuit in a heat-transferring manner. The elevations can be designed, for example, as cooling bodies in the form of so-called "pin-fin" bodies, which are arranged on the side of at least one coolant circuit facing the fluid of the first coolant circuit.

[0025] In a further embodiment variant, at least one coolant circuit is designed as a through opening, hole and / or recess in the housing of the storage device. The at least one coolant circuit can thus be implemented, for example, in the form of a hole in the housing of the storage device. In this case, the fluid of the first coolant circuit can also release heat to the coolant via a coolant guide on the housing. If the housing is made by casting, such an embodiment of the at least one coolant circuit can be realized in a simple manner.

[0026] The drive device for a hybrid vehicle or an electric vehicle according to the invention comprises a cooling system as described herein. In particular, the drive device may comprise an electric drive axle of a hybrid vehicle or an electric vehicle or an electric drive system for an axle. The drive device may comprise an electric motor and an optional transmission mechanism in order to provide a torque to drive at least one drive wheel of the hybrid vehicle or the electric vehicle. In addition to the electric motor, an electric control device may also be included, which in one embodiment may also be cooled by means of a coolant of a second coolant circuit. In addition, the drive device may also comprise an energy storage device, which supplies electrical energy to the electric motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will now be described in detail with reference to the accompanying drawings, in which:

[0028] Figure 1 A drive device according to the invention is shown in a motor vehicle, the drive device having a cooling system according to the invention according to a first embodiment;

[0029] Figure 2a Show according to Figure 1 A longitudinal section of a storage device of a cooling system according to the present invention;

[0030] Figure 2b Show according to Figure 1 and Figure 2a A cross-sectional view of a storage device of a cooling system according to the present invention;

[0031] Figure 3a A longitudinal section showing a storage device of a cooling system according to the invention according to a second embodiment;

[0032] Figure 3b Show according to Figure 3a A cross-sectional view of a storage device of a cooling system according to the present invention; and

[0033] Figure 4 A cross-section through a storage device of a cooling system according to the invention is shown according to a third embodiment. DETAILED DESCRIPTION

[0034] Figure 1 The drive device 100 according to the invention is shown in a vehicle according to the invention, which can be constructed as an electric vehicle or a hybrid vehicle 105. Depending on the design of the vehicle, the vehicle can be driven either purely electrically or partially electrically and partially by an internal combustion engine. The drive device 100 is configured to drive at least one drive wheel 110 of the electric vehicle 105. For this purpose, an electric motor (not shown here) can be provided, which is supplied with electric energy from an electric energy storage device. In order to implement the mechanical energy on the drive wheel 110, a transmission mechanism (also not shown here) can also be provided. Optionally, the transmission mechanism is configured to be driven by another drive machine (for example a reciprocating piston engine) not shown, so that the vehicle is constructed as a hybrid vehicle. In addition, a differential (not shown here) can be provided to transmit the driving power to the Figure 1 On the two drive wheels 110 of the axle shown in FIG.

[0035] The electric or hybrid vehicle 105 further comprises a cooling system 115 according to the invention, which is described below in Figures 2a to 4 The cooling system 115 may be part of a hydraulic system for cooling and lubricating heat consumers (not shown) of the electric vehicle 105 , but these are not discussed in detail here.

[0036] The cooling system 115 comprises a reservoir 120, which is configured to accommodate and provide a fluid of a first coolant circuit. The fluid can be transported from a sump 130 (here an oil sump) to an interior space 135 of a housing 140 of the reservoir 120 by means of a pump 125 of a hydraulic system, which is configured as a vane pump, so that a sufficient amount of fluid for cooling or lubricating components is available at any time during operation. The reservoir 120 can also be part of a hydraulic system, and the fluid it provides can be conveyed to at least one further pump 145 in order to provide the components with fluid, i.e., coolant and / or lubricant. In the sense of the invention, oil is preferred as the fluid.

[0037] The pump 125 and the further pump 145 are operatively connected via a common shaft 150 to an electric motor 155 which drives both pumps 125 , 145 .

[0038] The housing 140 is shown here with a bottom element 160 and side walls 165, 170, wherein the housing 140 is depicted as being open upwards. Of course, it is also conceivable that a cover element (not shown) is provided so that the housing 140 can spatially delimit the interior space 135 on all sides. The housing 140 is here a cast component produced by casting.

[0039] The cooling system 115 comprises a second coolant circuit which is designed at least for cooling power electronics 175 of the drive device 100, in particular a plate cooler of the power electronics. The power electronics 175 are fluidically connected to a heat exchanger 185 via a tubular coolant line 180 of the second coolant circuit. Figures 1 to 3b In the example of FIG. 1 , only a single coolant line 180 is shown by way of example, wherein it is of course also conceivable that further coolant lines (not shown here) are arranged and constructed in a similar manner, see Figure 4 Everything said here and below regarding the coolant line 180 can be applied analogously to the other coolant lines accordingly.

[0040] In accordance with Figure 1 to Figure 2b In a first embodiment of the present invention, the coolant line 180 extends substantially horizontally between two opposite side walls 165, 170 of the housing 140, wherein the coolant is arranged in a manner similar to that of the embodiment of the present invention. Figure 1 and Figure 2a In the illustration of , the coolant line 180 flows from right to left according to the arrows shown and extends through the housing 140 below the fluid level 200 in the interior 135 of the housing 140. The coolant line 180 is therefore arranged in the housing 140, wherein the fluid level 200 within the housing 140 is always selected such that the coolant line 180 is surrounded by the fluid 205 all around in the interior 135 of the housing 140.

[0041] exist Figure 2bIn the cross-sectional view of the storage device 120 shown in FIG, an inlet line 210 is shown, which guides the fluid delivered by the pump 125 to the storage device 120. The inlet line 210 of the first coolant circuit is designed to connect the interior 135 of the housing 140 to the pump 125 fluid. The inlet line 210 is positioned and oriented relative to the tubular coolant line 180 in such a way that the volume flow of the first coolant circuit delivered by the pump 125 is directed to the coolant line 180 and thus generates turbulence at and around the coolant line 180 during delivery into the storage device 120, thereby improving the heat transfer between the fluid 205 of the first coolant circuit and the coolant of the second coolant circuit. Therefore, the cooling effect is improved by the system proposed here, whereby the heat exchanger 180 and / or the plate cooler of the power electronics 175 can be reduced in size compared to known cooling concepts. As a result, an already existing filling material of the reservoir can be utilized or optimized in a simple manner in order to create a turbulent environment around the coolant line.

[0042] Figure 3a and Figure 3b A second embodiment of the cooling system 115 is shown, wherein only the embodiment according to Figure 1 to Figure 2b The difference from the first embodiment.

[0043] The inlet line 210 is configured in this case so that the longitudinal section of the coolant line 180 arranged between the side walls 165 and 170 is accommodated in the inlet line and arranged coaxially with the inlet line. Here, the outer diameter of the tubular coolant line 180 is selected to be smaller than the inner diameter of the inlet line 210, so that an annular gap is formed between the coolant line 180 and the inlet line 210, and before the fluid 205 enters the interior space 135 of the housing 140, the fluid of the first coolant circuit flows along the arrow from Figure 3a and Figure 3b The input end 300 shown in FIG. 1 is guided through the annular gap until Figure 3a 305 is shown in the output end 306 of the heat exchanger 185. The arrow pointing essentially to the right in the input line 210 and the arrow pointing oppositely to the left in the coolant line 180 are intended to illustrate that the coolant of the second coolant circuit and the fluid of the first coolant circuit are guided in countercurrent to one another, thereby reducing the required cooling performance at the heat exchanger 185. Thus, a double-walled coolant guidance is achieved by this example.

[0044] According to Figure 4The third embodiment is intended to illustrate that the coolant line 180 does not necessarily need to be a pipe to guide the fluid 205 through the interior space of the housing 140, but when the coolant line 180 is configured as a through opening, hole and / or recess in the housing 140 of the storage device 120, an improvement in cooling performance can also be achieved. In addition, based on the overlapping circles or holes 400 in the right side wall 170 of the housing 140, it is explained that more than one coolant line 180 can also be provided. The guiding method of the input line 210 is similar to Figure 2b The same applies, wherein reference is made to the corresponding textual content.

[0045] For all embodiments, the coolant line 180 may have ridges, depressions, projections and / or recesses on the side facing the fluid of the first coolant circuit (i.e., on the outer circumference), thereby increasing the surface of the outer skin of the coolant line 180 in contact with the fluid 205 of the first coolant circuit. In particular, the outer circumferential side of the coolant line 180 may be increased by pin fins.

[0046] The invention is not limited to the disclosed embodiments. Other embodiments or variants may be apparent to a person skilled in the art when using the invention and when analyzing the drawings, the description and the claims in detail. In particular, the disclosed embodiments may be combined with one another in order to optimize the cooling performance of the system as well as possible and thus to design the cooling elements of the heat exchanger 185 and / or the power electronics 175 as thin as possible, save construction space and thus be more cost-effective.

[0047] Reference numerals list

[0048] 100 drive unit

[0049] 105 Electric vehicles

[0050] 110 driving wheel

[0051] 115 Cooling System

[0052] 120 reserve device

[0053] 125 Pumps

[0054] 130 bottom shell

[0055] 135 Interior Space

[0056] 140 Shell

[0057] 145 Pumps

[0058] 150 shaft

[0059] 155 Electric Motor

[0060] 160 bottom element

[0061] 165 side wall

[0062] 170 side wall

[0063] 175 Power Electronics

[0064] 180 Coolant Line

[0065] 185 heat exchanger

[0066] 200 Fluid Level

[0067] 205 Fluid

[0068] 210 Input Line

[0069] 300 Input

[0070] 305 output terminal

[0071] 400 holes

Claims

1. A cooling system (115) for a drive device (100) of a hybrid vehicle or an electric vehicle (105), the cooling system comprising a storage device (120) which is configured to receive and provide a fluid of a first coolant circuit, the fluid of the first coolant circuit being conveyed from a bottom shell (130) into an interior space (135) of a housing (140) of the storage device (120) by means of a pump (125), wherein: At least one coolant line (180) of a second coolant circuit is arranged on and / or in the housing (140), the at least one coolant line being designed to conduct coolant from the power electronics (175) to the heat exchanger (185).

2. The cooling system (115) according to claim 1, wherein: An inlet line (210) of a first coolant circuit is arranged on the storage device (120), which inlet line is designed to fluidically connect an interior (135) of the housing (140) to the pump (125).

3. The cooling system (115) according to claim 1 or claim 2, wherein: The at least one coolant line (180) is substantially tubular and passes through an interior space (135) of the housing (140) at least in sections, wherein the at least one coolant line (180) is at least partially surrounded by a fluid of a first coolant circuit located in the interior space (135) of the housing (140).

4. The cooling system (115) according to claim 2 in combination with claim 3, wherein: The feed line (210) is positioned and oriented relative to the at least one coolant line (180) in such a way that a volume flow of the first coolant circuit is directed toward the at least one coolant line (180).

5. The cooling system (115) according to claim 2, wherein: The input line (210) is configured to accommodate at least one longitudinal section of the at least one coolant line (180), wherein an inner diameter of the input line (210), at least in a region accommodating the at least one coolant line (180), is greater than an outer diameter of the at least one coolant line (180).

6. The cooling system (115) according to claim 5, wherein: The feed line (210) is arranged coaxially with the at least one coolant line (180), at least in a region accommodating the at least one coolant line (180).

7. The cooling system (115) according to any one of the preceding claims, wherein: The at least one coolant line (180) has a ridge, a depression, a projection and / or a recess on a side facing the fluid of the first coolant circuit, thereby increasing a contact area with the fluid of the first coolant circuit in an interior space (135) of the housing (140).

8. The cooling system (115) according to claim 1 or claim 2, wherein: The at least one coolant line (180) is designed as a through-opening, a hole (400) and / or a recess in a housing (140) of the storage device (120).

9. The cooling system (115) according to any one of the preceding claims, wherein: The housing (140) is made by casting.

10. A drive device (100) for a hybrid vehicle or an electric vehicle (105), comprising a cooling system (115) according to any one of the preceding claims.

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