Electric drive system for motor vehicle and motor vehicle

Abstract

The invention relates to an electric drive system for a motor vehicle and to a motor vehicle having such an electric drive system. The invention relates to an electric drive system for a motor vehicle, comprising an electric drive assembly (1), which comprises a drive motor, which has a stator and a rotor, which can be operated with alternating current, and which comprises a transmission, which is connected to the rotor, therefore, the driving torque of the driving motor is transmitted to a driving wheel (9) of the motor vehicle. The electric driving system further comprises a power battery system (20), the power battery system comprises a battery shell (3), a power battery contained in the battery shell and an inverter assembly arranged in the battery shell, and the inverter assembly comprises an inverter and an inverter controller. The inverter assembly is configured to be used for converting direct current of the power battery into alternating current used for driving the motor.

Description

Technical Field

[0001] The present invention relates to an electric drive system for a motor vehicle. The present invention also relates to a motor vehicle, in particular a hybrid vehicle or a pure electric vehicle, having such an electric drive system. Background Art

[0002] At present, more and more attention is paid to electric vehicles, such as pure electric vehicles or hybrid vehicles. For this purpose, the motor vehicle may have an electric drive system. In some known electric drive systems, the drive motor and the transmission device and the inverter component are integrated in a common electric drive assembly. For example, patent document WO2019238343A1 discloses such an electric drive assembly.

[0003] The inventors of the present application have found in the research and development of the product that the inverter assembly is more prone to failure than the drive motor and the transmission. When the drive motor, the transmission and the inverter assembly are integrated in a common electric drive assembly, once a component of the electric drive assembly fails, maintenance is costly. Alternatively, the entire electric drive assembly may need to be disassembled and replaced as a whole if necessary, which is costly. Summary of the invention

[0004] The object of the present invention is to provide an electric drive system for a motor vehicle which operates reliably, is easy to maintain and has more favorable maintenance costs than in the prior art.

[0005] A first aspect of the present invention relates to an electric drive system for a motor vehicle. The electric drive system includes an electric drive assembly, the electric drive assembly includes a drive motor, the drive motor has a stator and a rotor, the drive motor can be operated with alternating current, and the electric drive assembly includes a transmission device, the transmission device is connected to the rotor to transmit the drive torque of the drive motor to the drive wheels of the motor vehicle. The electric drive system also includes a power battery system, the power battery system includes a battery housing, a power battery contained in the battery housing, and an inverter assembly arranged in the battery housing, the inverter assembly includes an inverter and an inverter controller, and the inverter assembly is configured to convert the direct current of the power battery into alternating current for the drive motor.

[0006] In the electric drive system according to the present invention, by integrating the inverter assembly into the power battery system, the electric drive assembly can be constructed with lower maintenance, and the inverter assembly can be maintained more easily and at a lower cost. In addition, the electric drive assembly can be constructed more compactly without the inverter assembly, wherein the structural space in the housing of the electric drive assembly for accommodating the inverter assembly and the cooling circuit for cooling the inverter assembly can be eliminated. Further, this can facilitate the overall arrangement of the electric drive assembly in the motor vehicle. Typically, the structural space available for arranging the electric drive assembly in a motor vehicle is very tight.

[0007] In the electric drive system according to the present invention, the power battery system can directly output AC power to the outside, and in particular can directly output not only AC power but also DC power to the outside; the electric drive assembly can directly work with the input AC power.

[0008] In some embodiments, the inverter assembly may be disposed on a housing lower part of the battery housing.

[0009] In some embodiments, the housing lower part may have an inspection opening for the inverter assembly, and the inspection opening may be closed by a detachable cover. When the inverter assembly needs to be maintained or replaced, the cover may be removed from the inspection opening to release the inspection opening, and the inverter assembly may be reached through the open inspection opening.

[0010] In some embodiments, the power battery system may be provided with a monitoring circuit for monitoring the inspection port, the monitoring circuit comprising a first circuit portion disposed in the lower part of the housing, a second circuit portion disposed in the cover plate, and a signaling element, wherein when the inspection port is closed by the cover plate, the first circuit portion and the second circuit portion are electrically connected, and when the cover plate is removed from the inspection port, the first circuit portion and the second circuit portion are electrically separated, and the signaling element can send a signal about the opening and / or closing of the inspection port to the battery management unit of the power battery system. This can ensure safety when maintaining and / or replacing the inverter assembly.

[0011] In some embodiments, the housing lower part may be provided with a surrounding first seal in the wall region surrounding and defining the inspection opening, and / or the cover plate may have a surrounding second seal for sealing the inspection opening. Preferably, when the inspection opening is closed by the cover plate, the first seal and the second seal act together to seal the inspection opening.

[0012] In some embodiments, the lower shell part can be provided with a plurality of first receiving holes in the wall area surrounding and defining the inspection opening, and the cover plate can have a plurality of second receiving holes. When the inspection opening is closed by the cover plate, each first receiving hole is aligned with one of the corresponding second receiving holes and receives a fastening device, such as a threaded fastener, especially a screw, for fixing the cover plate to the lower shell part.

[0013] In some embodiments, the drive motor may be configured as a three-phase motor, and the inverter assembly may be configured to convert direct current from a power battery into three-phase alternating current for the drive motor.

[0014] In some embodiments, the drive motor can be configured as a six-phase motor having two three-phase phase systems, and the inverter assembly is configured to convert direct current from a power battery into six-phase alternating current for the drive motor, wherein the inverter has a first switching unit and a second switching unit, the first switching unit being assigned to a first phase system of the three-phase drive motor, and the second switching unit being assigned to a second phase system of the three-phase drive motor.

[0015] In order to supply power to each phase of the drive motor, the inverter controller switches each switch of the switching unit of the inverter according to a predetermined switching pattern. These switches can be power semiconductors, such as IGBTs or power MOSFETs.

[0016] In some embodiments, the transmission may be a continuously variable transmission or a stepped transmission.

[0017] In some embodiments, the transmission device may be a single-stage reduction device.

[0018] In some embodiments, the transmission may include a spur gear set and / or a planetary gear set and / or a bevel gear set and / or a crown gear set.

[0019] A second aspect of the present invention relates to a motor vehicle, for example a hybrid vehicle or a purely electric motor vehicle, which can have an electric drive system according to any specific embodiment of the present invention.

[0020] Further features of the invention can be derived from the drawings and the description thereof. The features and feature combinations mentioned above in the specification, the features and features mentioned below in the description in conjunction with the drawings, and the features and feature combinations shown individually in the drawings can be used not only in the respectively indicated combination, but also in other combinations or individually.

[0021] All features mentioned in this article can be combined arbitrarily as long as they are not contradictory. All feasible feature combinations are technical contents recorded in this article. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The invention will now be explained in more detail using exemplary embodiments and with reference to the accompanying drawings.

[0023] The attached pictures are as follows:

[0024] Figure 1 is a schematic bottom view of an exemplary embodiment of an electric drive system according to the present invention.

[0025] Figure 2 yes Figure 1 Schematic diagram of the electric drive assembly of the electric drive system.

[0026] Figure 3 and Figure 4 yes Figure 1 Schematic top view and bottom view of the power battery system of the electric drive system.

[0027] Figure 5A and 5B are schematic diagrams of two implementations of inverter components.

[0028] Figure 6 is a schematic diagram of the access opening for the inverter assembly.

[0029] Figure 7 and Figure 8 Schematic top view and cross-sectional view of a cover for an inspection opening. DETAILED DESCRIPTION

[0030] Figure 1 1 is a schematic bottom view of an exemplary embodiment of an electric drive system according to the present invention. The electric drive system is used to drive a motor vehicle, more specifically, to drive the drive wheels 9 of the motor vehicle. The motor vehicle can be a pure electric vehicle or a hybrid vehicle, especially a sedan.

[0031] The electric drive system may include an electric drive assembly 1 and a power battery system 20. The electric drive assembly 1 may be assigned to any axle of the motor vehicle, for example, to the front axle or the rear axle. Alternatively, in an embodiment not shown, the electric drive assembly 1 may be assigned not only to the front axle of the motor vehicle but also to the rear axle of the motor vehicle, so that the motor vehicle is configured as an all-wheel drive vehicle. The power battery system 20 may output alternating current via its electrical interface 25. The electric drive assembly 1 may input alternating current via its electrical interface 26. The power battery system 20 and the electric drive assembly 1 may be electrically connected to each other via their electrical interfaces 25, 26.

[0032] Figure 2 yes Figure 1Schematic diagram of an electric drive assembly 1 of an electric drive system of a motor vehicle. The electric drive assembly 1 has an electric motor 2 and a transmission 4. The electric motor 2 has a stator 5 and a rotor 6 rotatably supported relative to the stator 5. The rotor 6 is coupled to the transmission 4 via a rotor shaft 7. The transmission 4 transmits the torque of the rotor 6 to the drive wheels 9 of the motor vehicle via different transmission stages 8. The transmission 4 may include a plurality of spur gear sets. Additionally or alternatively, the transmission 4 may include at least one planetary gear set.

[0033] In one embodiment, the motor 2 can be configured as a three-phase AC motor having a phase system consisting of phases U, V, and W. In another embodiment, the motor 2 can be configured as a six-phase rotating field motor having a first phase system consisting of phases U, V, and W and a second phase system consisting of phases U', V', and W'. It can be understood that the electrical interface 25 of the power battery system 20 and the electrical interface 26 of the electric drive assembly 1 can be designed to adapt to the specific design of the motor 2.

[0034] The electric drive assembly 1 has a coolant circuit 12, schematically depicted by dashed lines, for cooling the stator 5 of the electric machine 2. To this end, a coolant circulating in the coolant circuit 12 flows through the stator 5. The coolant may be a cooling liquid, for example water.

[0035] Furthermore, the electric drive assembly 1 has a lubricant circuit 14 schematically depicted by a solid line, in which a lubricant for lubricating the transmission 4 circulates. The lubricant 15 can be, for example, oil and is conveyed from a reservoir 16, for example an oil sump, via a filter 17 to the transmission 4 for lubrication and conveyed back to the reservoir 16 via a first return path 18. In this case, the lubricant 15 can be guided through the rotor shaft 7, which is designed as a hollow body, to cool the rotor 6 of the drive motor 2 and can be guided back to the reservoir 16 via a second return path 19.

[0036] The lubricant circuit 14 and the coolant circuit 12 can be thermally coupled via a lubricant-coolant heat exchanger. In normal operation of the drive motor 2, the heat exchanger transfers the heat of the lubricant 15 to the coolant in the coolant circuit 12 in order to cool the lubricant 15. This can prevent the lubricant 15 from exceeding a predetermined upper temperature limit. This upper temperature limit can be 100° C., for example.

[0037] When the motor vehicle is started, when the lubricant 15 has the ambient temperature, the lubricant 15 has a high viscosity. This high viscosity is undesirable because it causes losses in the transmission 4. Therefore, if the temperature of the lubricant 15 is lower than a predetermined lower temperature limit (for example, the lower temperature limit may be 60° C.), the lubricant 15 may be heated. The temperature of the lubricant may be detected, for example, by a temperature sensor in the lubricant circuit 14, not shown, and provided to the control device of the electric drive assembly 1. If necessary, the lubricant may be heated directly or indirectly by an electric heating device, not shown.

[0038] Figure 3 and Figure 4 yes Figure 1 Schematic top view and bottom view of the power battery system 20 of the electric drive system. Figure 3 The upper shell part of the battery shell 3 is omitted, and only the lower part 31 of the battery shell 3 is described, so that the principle structure of the power battery system 20 can be described more clearly. The power battery system 20 includes a power battery accommodated in the battery shell 3, and the power battery may include a plurality of battery modules 21. Each battery module 21 may be composed of a plurality of battery cells. These battery modules 21 may be connected in series and / or in parallel. It is possible that these battery modules 21 may have different connection modes in different operating states. For example, four battery modules 21 may be connected in series with each other when outputting electrical energy, and may be switched to be connected in parallel with each other when charging. The power battery may be equipped with a cell management circuit 22. The cell management circuit 22 may be designed to ensure the electrical balance state of each battery cell of each battery module 21. The power battery may be equipped with a battery management unit 23. The battery management unit 23 may be designed to monitor and manage the power battery. For example, by collecting and analyzing parameters such as the voltage, current, temperature, and SoC of the power battery and / or battery module, and thereby controlling the discharge and charging processes of the power battery, the power battery can be protected and its comprehensive performance can be improved.

[0039] As in Figure 2 and Figure 4 As can be seen in the figure, the power battery system 20 can be provided with a DC charging interface 10 and a DC output interface 11 in the housing lower part 31 of the battery housing 3. The DC charging interface 10 can be connected to the DC charging interface in the body of the motor vehicle via a cable, thereby enabling the power battery to be charged using a charging gun at a charging station. The DC output interface 11 can supply DC power to the DC high-voltage assembly of the motor vehicle, such as the vehicle air conditioner.

[0040] The power battery system 20 includes an integrated inverter assembly 24. The inverter assembly 24 may be disposed on the housing lower part 31 of the battery housing 3. The inverter assembly 24 is electrically connected to the battery management unit 23 via a cable so as to obtain direct current from the power battery under the management of the battery management unit 23. The inverter assembly 24 may include an inverter and an inverter controller 36 (see Figure 5A and 5B ), wherein the inverter can convert the DC power into the required AC power under the control of the inverter controller 36, and the AC power can be output through the electrical interface 25. During the braking energy recovery, the inverter can convert the AC power from the electric drive assembly 1 into the required DC power under the control of the inverter controller 36, and the DC power energy is stored in the power battery.

[0041] In order to operate the drive motor 2 of the electric drive assembly 1, the power battery system 20 can supply power to the phases U, V, W of the stator 5 of the three-phase motor or the phases U, V, W and U', V', W' of the stator of the six-phase motor via the inverter assembly 24. The inverter of the inverter assembly 24 has branches or half-bridges with controllable switches, and the number of the branches or half-bridges corresponds to the number of the phases U, V, W of the stator 5 or the number of the phases U, V, W and U', V', W' of the stator 5.

[0042] In the first option, if Figure 5A As shown, the inverter of the inverter assembly 24 may have a single switch unit 34 electrically connected to phases U, V, and W. The switch unit 34 may have three half-bridges with controllable switches. Here, in order to supply power to phases U, V, and W, the switches of the switch unit 34 are controlled by the inverter controller 36 according to a predetermined switching sequence, so that the power battery system 20 can output three-phase alternating current to the electrical interface 26 of the electric drive assembly 1 via the inverter assembly 24 and the electrical interface 25, and the drive motor 2 can be operated with the three-phase alternating current to generate a rotating magnetic field in the drive motor 2 for driving the rotor 6.

[0043] In the second solution, the phases U, V, and W of the stator 5 of the drive motor 2 may constitute a three-phase first phase system, and the phases U', V', and W' of the stator 5 of the drive motor 2 may constitute a three-phase second phase system. Figure 5BAs shown, the inverter of the inverter assembly 24 may have a first switch unit 34 electrically connected to the first phase system of the drive motor 2 and a second switch unit 35 electrically connected to the second phase system of the drive motor 2 in parallel with the first switch unit 34. Each switch unit 34, 35 may have three half-bridges with controllable switches. Here, in order to supply power to phases U, V, W and U', V', W', the switches of each switch unit 34, 35 are controlled by the inverter controller 36 according to a predetermined switching sequence, so that the power battery system 20 can output six-phase alternating current to the electrical interface 26 of the electric drive assembly 1 via the inverter assembly 24 and the electrical interface 25, and the drive motor 2 can be operated with the six-phase alternating current to generate a rotating magnetic field in the drive motor 2 for driving the rotor 6.

[0044] It is understandable that the power battery system 20 may have not only an electrical interface for outputting three-phase alternating current, but also an electrical interface for outputting six-phase alternating current, thereby expanding the application range of the power battery system for motor vehicles.

[0045] like Figures 6 to 8 As shown, in order to maintain and / or replace the inverter assembly 24, an inspection opening 27 can be provided in the housing lower part 31 of the battery housing 3, and the inspection opening can be sealed by a cover plate 32. When the inverter assembly 24 needs to be maintained or replaced, the motor vehicle can be raised in the workshop so that the bottom of the motor vehicle and thus the bottom of the housing lower part 31 of the battery housing 3 can be easily accessed, wherein the cover plate 32 can be removed from the housing lower part 31, so that the inspection opening 27 is released, and the inverter assembly 24 can be reached through the open inspection opening 27.

[0046] The power battery system 20 may be provided with a monitoring circuit 30 for monitoring the inspection port 27, and the monitoring circuit 30 may include a first circuit portion 30a disposed in the lower housing part 31, a second circuit portion 30b disposed in the cover plate 32, and a signaling element 28. When the inspection port 27 is closed by the cover plate 32, the first circuit portion 30a and the second circuit portion 30b are electrically connected, and when the cover plate 32 is removed from the inspection port 27, the first circuit portion 30a and the second circuit portion 30b are electrically separated, so that the signaling element 28 can send a signal about the opening of the inspection port 27 to the battery management unit 23 of the power battery system 20. Then, the battery management unit 23 puts the inverter assembly 24—and other electrical components of the power battery system 20, if necessary—into an open circuit state to ensure safety when the inverter assembly 24 is maintained and / or replaced. When the removed cover plate 32 is reinstalled on the inspection opening 27, the first circuit portion 30a is electrically connected to the second circuit portion 30b again, so that the signaling element 28 can send a signal about the re-closure of the inspection opening 27 to the battery management unit 23 of the power battery system 20. Then the battery management unit 23 restores the inverter assembly 24 - and other electrical components of the power battery system 20 if necessary - from the open circuit state to the normal working state.

[0047] In order to install the cover plate 32 on the inspection opening 27, the lower shell part 31 can be provided with a plurality of first receiving holes in the wall area surrounding and defining the inspection opening 27, and the cover plate 32 can have a plurality of second receiving holes. When the inspection opening 27 is closed by the cover plate 32, each first receiving hole is aligned with one of the corresponding second receiving holes and receives a fastening device, such as a threaded fastener, for fixing the cover plate 32 to the lower shell part 31.

[0048] In order to seal the inspection opening 27 by the cover plate 32, the housing lower part 31 can be provided with a surrounding first seal 29 in the wall region surrounding and defining the inspection opening 27, and the cover plate 32 can have a surrounding second seal 33. When the inspection opening 27 is closed by the cover plate 32, the first seal 29 and the second seal 32 act together so that the inspection opening 27 is sealed in a fluid-tight manner.

[0049] It should be noted that the terms used herein are for the purpose of illustrating specific aspects only and are not intended to limit the disclosure. As used herein, the singular forms "a" and "the one" shall include the plural forms unless the context clearly states otherwise. It is understood that the terms "include" and "comprises" and other similar terms, when used in the application documents, specify the existence of the stated operations, elements and / or parts, without excluding the existence or addition of one or more other operations, elements, parts and / or combinations thereof. As used herein, the term "and / or" includes all arbitrary combinations of one or more related enumerated items. In the description of the drawings, similar reference numerals always represent similar elements.

[0050] The thickness of the elements in the accompanying drawings can be exaggerated for the sake of clarity. It is also understood that if an element is referred to as being on another element, coupled to another element or connected to another element, then the element can be directly formed on the other element, coupled to it or connected to it, or one or more intervening elements can be arranged between them. On the contrary, if the expressions "directly on...", "directly coupled to..." and "directly connected to..." are used herein, then there is no intervening element. Other words used to illustrate the relationship between elements should be similarly interpreted, such as "between..." and "directly between...", "attachment" and "direct attachment", "adjacent" and "directly adjacent", etc.

[0051] Terms such as "top," "bottom," "above," "below," "above," "below," etc. are used herein to describe the relationship of one element, layer or region to another element, layer or region as illustrated in the drawings. It will be understood that these terms are intended to encompass other orientations of the device in addition to the orientation depicted in the drawings.

[0052] It is to be understood that although the terms "first", "second", etc. may be used herein to describe different elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. Therefore, the first element may be referred to as the second element without departing from the teachings of the present invention.

[0053] It is also conceivable that all exemplary embodiments disclosed herein can be combined with one another in any desired manner.

[0054] Finally, it should be pointed out that the above embodiments are only used to understand the present invention, and do not limit the protection scope of the present invention. For those skilled in the art, modifications can be made based on the above embodiments, and these modifications do not depart from the protection scope of the present invention.

Claims

1. An electric drive system for a motor vehicle, characterized in that: The electric drive system comprises an electric drive assembly (1), the electric drive assembly comprising a drive motor (2), the drive motor having a stator (5) and a rotor (6), the drive motor being operable with alternating current, and the electric drive assembly comprising a transmission device (4), the transmission device being connected to the rotor to transmit the drive torque of the drive motor to the drive wheels (9) of the motor vehicle; and The electric drive system comprises a power battery system (20), the power battery system comprising a battery housing (3), a power battery contained in the battery housing (3), and an inverter assembly (24) arranged in the battery housing, the inverter assembly comprising an inverter and an inverter controller (36), and the inverter assembly is configured to convert direct current of the power battery into alternating current for driving a motor (2).

2. The electric drive system for a motor vehicle according to claim 1, characterized in that: The inverter assembly (24) is arranged on a housing lower part (31) of the battery housing (3).

3. The electric drive system for a motor vehicle according to claim 2, characterized in that: The housing lower part (31) has an inspection opening (27) for the inverter assembly (24), which can be closed by a removable cover (32).

4. The electric drive system for a motor vehicle according to claim 3, characterized in that: The power battery system (20) is provided with a monitoring circuit (30) for monitoring the inspection port, the monitoring circuit comprising a first circuit portion (30a) arranged in a lower part (31) of a housing, a second circuit portion (30b) arranged in a cover plate (32), and a signaling element (28), wherein when the inspection port (27) is closed by the cover plate (32), the first circuit portion (30a) and the second circuit portion (30b) are electrically connected, and when the cover plate (32) is removed from the inspection port (27), the first circuit portion (30a) and the second circuit portion (30b) are electrically separated, and the signaling element (28) can send a signal regarding the opening and / or closing of the inspection port to a battery management unit (23) of the power battery system (20).

5. The electric drive system for a motor vehicle according to claim 3 or 4, characterized in that: The housing lower part (31) is provided with a circumferential first seal (29) in a wall region surrounding and defining the inspection opening (27), and the cover plate (32) has a circumferential second seal (33). When the inspection opening (27) is closed by the cover plate (32), the first seal (29) and the second seal (33) act together to seal the inspection opening (27).

6. The electric drive system for a motor vehicle according to any one of claims 3 to 5, characterized in that: The housing lower part (31) is provided with a plurality of first receiving holes in a wall area surrounding and defining the inspection opening (27), and the cover plate (32) has a plurality of second receiving holes. When the inspection opening (27) is closed by the cover plate (32), each first receiving hole is aligned with one of the corresponding second receiving holes and receives a fastening device for fixing the cover plate to the housing lower part.

7. The electric drive system for a motor vehicle according to any one of claims 1 to 6, characterized in that: The drive motor (2) is configured as a three-phase motor, and the inverter assembly (24) is configured to convert direct current of the power battery into three-phase alternating current for the drive motor (2); or The drive motor (2) is configured as a six-phase motor having two three-phase phase systems, and the inverter assembly is configured to convert direct current from a power battery into six-phase alternating current for the drive motor (2), wherein the inverter has a first switching unit (34) and a second switching unit (35), wherein the first switching unit (34) is assigned to a first phase system of the three phases of the drive motor (2), and the second switching unit (35) is assigned to a second phase system of the three phases of the drive motor (2). 8 . A motor vehicle, for example a purely electric motor vehicle or a hybrid vehicle, comprising an electric drive system according to claim 1 .

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