JP2023551936A - Integrated drivetrain assembly for electric vehicles and electric vehicles - Google Patents

Abstract

The present disclosure relates to driveline assemblies for electric vehicles. The driveline system includes an electric motor, a power inverter, a speed reducer, and one cooling circuit with a single inlet and a single outlet. The cooling circuit is configured to distribute oil flowing throughout the integrated drivetrain assembly to lubricate and cool all components therein, and the cooling circuit is configured to distribute oil flowing throughout the integrated drivetrain assembly to lubricate and cool all components therein, and the cooling circuit is configured to distribute oil flowing throughout the integrated drivetrain assembly to lubricate and cool all components therein; an oil distribution passageway disposed within the cooling plate configured to cool the switching device, and at least one baffle provided within the distribution passageway and corresponding to the cooling plate for guiding oil flowing through the distribution passageway; A cover is provided surrounding the oil distribution passageway and in sealing contact with the at least one baffle. The present disclosure also relates to an electric vehicle comprising an integrated drivetrain assembly according to the above-mentioned comprising.

Description

Embodiments of the present disclosure generally relate to integrated driveline assemblies for electric vehicles and electric vehicles comprising integrated driveline assemblies.

The trend to design and build fuel-efficient, low-emission vehicles is increasing dramatically, driven by environmental concerns as well as concerns about increasing fuel costs. At the forefront of this trend are BEVs ('battery electric vehicles'), HEVs ('hybrid electric vehicles'), PHEVs ('plug-in hybrid electric vehicles'), extended range EVs, and FCEVs ('fuel cell electric vehicles'). This was the development of an electric vehicle that combines a relatively efficient combustion engine with an electric drive motor. Electric vehicles can include components that generate heat, particularly drivetrain systems. Excessive heat generation can cause performance degradation or component damage. In particular, cooling solutions for high-power electric vehicles, e.g. BEVs with a power greater than 200 kW, require at least two cooling circuits in the drivetrain system, e.g. one oil cooling circuit for the motor/gear gearbox and one for the inverter. Contains a water cooling circuit, which requires at least two hydraulic circuits with at least two pumps, but the arrangement of each cooling circuit with different coolants to cool different components within the driveline system is more complex. , and the cost will be high. However, this oil-cooled motor and speed reducer guarantees higher performance and efficiency.

At low powers, below 100 kW, the high cost justifies the use of both oil and water cooling in one system, even though the advantages are clear by the possibility of further downsizing the motor. things become difficult. Therefore, using only oil cooling for the entire system can be an attractive solution if the inverter can be efficiently cooled by oil, which constitutes a major problem with traditional designs of inverter cooling. do.

Therefore, it would be desirable if any improvement in oil cooling design for driveline systems for electric vehicles could be provided with at least a simple configuration, high efficiency, and low cost.

Aspects and advantages of the invention are set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.

According to one aspect disclosed herein, an integrated driveline assembly for an electric vehicle is provided. The driveline assembly includes an electric motor comprising a rotor and a stator, a power inverter electrically connected to the electric motor and configured to provide electrical energy to the stator, coupled to the electric motor and provided by the rotor. and a reduction gear configured to receive the torque. The driveline assembly further includes one cooling circuit having a single inlet and a single outlet. The cooling circuit is configured to distribute oil flowing throughout the integrated drivetrain assembly to lubricate and cool all components therein, and the cooling circuit is configured to distribute oil flowing throughout the integrated drivetrain assembly to lubricate and cool all components therein, and the cooling circuit is configured to distribute oil flowing throughout the integrated drivetrain assembly to lubricate and cool all components therein; an oil distribution passageway disposed within the cooling plate configured to cool the switching device, and at least one baffle provided within the distribution passageway and corresponding to the cooling plate for guiding oil flowing through the distribution passageway; A cover is provided surrounding the oil distribution passageway and in sealing contact with the at least one baffle.

In one embodiment, a sealing material is provided between the inner surface of the cover and one end of each of the at least one baffle.

In one embodiment, a sealing material is disposed on the inner surface of the cover.

In one embodiment, a plurality of cooling spikes are provided within the oil distribution passage, and the cooling spikes are arranged throughout the oil distribution passage in a high density.

In one embodiment, cooling spikes are provided on the cooling plate and cover.

In one embodiment, at least one power switching device is arranged between two cooling plates so that the power switching device can be cooled from both sides.

In one embodiment, the oil dispensed by the cooling circuit is an ultra-low viscosity oil.

In one embodiment, the driveline assembly further comprises an oil pump configured to communicate with the inlet to control oil flow through the cooling circuit.

In one embodiment, the oil pump is provided on the electric vehicle side and connected to the inlet when the integrated driveline assembly is installed on the electric vehicle or when the oil pump is integrated with the driveline assembly.

In one embodiment, the oil pump is a positive displacement pump.

In one embodiment, the driveline assembly is configured to communicate between the outlet and the oil pump for cooling oil discharged from the driveline assembly and transferring the cooled oil to the driveline assembly. The device further includes a heat sink.

In one embodiment, the heat sink is integrated with the drivetrain assembly or provided on the electric vehicle side.

According to another aspect disclosed herein, an electric vehicle is provided that includes the integrated driveline assembly described above.

These and other features, aspects, and advantages of the present disclosure will be better understood with reference to the following detailed description. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

A complete and enabling disclosure of the invention, including the best mode thereof, that is directed to those skilled in the art, is described herein with reference to the accompanying drawings.

1 is a schematic diagram of an integrated driveline assembly for an electric vehicle in accordance with an example aspect of the present disclosure. FIG. 2 is an exemplary diagram of a cooling plate and an oil distribution schematic diagram disposed within the cooling plate; FIG. 1 is a schematic diagram of a portion of a power inverter in accordance with an example aspect of the present disclosure, showing one example cooling plate and its cover; FIG. 1 is a schematic diagram of one exemplary arrangement of power switching devices and cooling plates of a power inverter; FIG. 1 is a schematic diagram of one exemplary arrangement of power switching devices and cooling plates of a power inverter; FIG.

Reference will now be made in detail to embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and letter symbols to refer to features of the drawings. Like or similar numbers in the drawings and description are used to refer to like or similar parts of the invention. As used herein, the terms "a," "an," and "the" refer to one of the elements, unless the context clearly dictates otherwise. or is intended to mean that there is more than one. The terms "comprising," "including," and "having" are intended to be inclusive, even if there are additional elements other than those listed. It means good. The terms "first" and "second" may be used interchangeably to distinguish one component from another and are intended to indicate the position or importance of the individual component. Unintentional.

Referring now to the drawings, where like numbers refer to like elements throughout the drawings, FIG. 1 illustrates a drivetrain assembly 1 according to one embodiment of the present disclosure. Driveline assembly 1 is generally integrated with a power inverter (not shown), an electric motor 12, and a speed reducer 13. The illustrated driveline assembly 1 is therefore a single unit.

Electric motor 12 can be a synchronous motor or an asynchronous motor. If it is a synchronous motor, it can include a wound rotor or a permanent magnet rotor. The peak power supplied by the electric motor can be between 10 KW and 80 KW, for example around 40 KW, with a nominal supply voltage of 48 V to 400 V, or up to 800 V for higher powers. In the case of an electric motor adapted to a high voltage supply, the nominal power supplied by this electric motor may be 25 KW. In the illustrated embodiment, electric motor 12 is a synchronous motor with permanent magnets and provides a peak power of 10 KW to 80 KW. Electric motor 12 may include a stator with three-phase windings, or a combination of two three-phase or five-phase windings.

Speed reducer 13 is coupled to electric motor 12 . The speed reducer 13 can convert the high speed and low torque of the electric motor into low speed and high torque. The speed reducer 13 may comprise two or more gears, one of which is driven by the electric motor 12, for example for torque increase due to speed reduction. The speed reducer consists of a drive gear driven by one transmission shaft (not shown) of an electric motor and another gear of larger diameter coupled to a driven mechanical load (not shown, for example a wheel shaft of a vehicle). It is possible to further include a transmission shaft, ie, an intermediate shaft, connecting the two.

In the illustrated embodiment, the electric motor 12 and the speed reducer 13 are designed with a high heat capacity. The power inverter is attached to the electric motor 12 by electrical wires and mechanically attached to the wall of the electric motor 12 or to the wall of the reducer 13 or to the walls of both the electric motor 12 and the reducer 13. Power inverter 11 converts direct current (“DC”) provided by an electrical energy storage unit (not shown) providing electrical energy at a nominal voltage into alternating current (“AC”) used by electric motor 2 . The power inverter includes at least one power switching device 17 (FIGS. 4A and 4B), such as a field effect transistor (“FET”), a metal oxide semiconductor field effect transistor (“MOSFET”), or an insulated gate bipolar transistor (“IGBT”). ) can be provided. For a nominal supply voltage of 48V, the power switching device can be a MOSFET transistor. For supply voltages corresponding to high voltages, the power switching device 17 can be an IGBT.

Referring to FIG. 1, electric motor 12 is housed in one housing (not shown) and reducer 13 is housed in another housing (not shown). The two housings may be integrated. The two housings can be rigidly fixed to each other, for example by screws. Here, a sealing wall is provided between the two housings.

In some embodiments, cooling fins (not shown) may be provided for heat dissipation to the outside of the driveline assembly 1. The cooling fins may be carried by the outer surface of the housing. These cooling fins are, for example, made integrally with the housing. These cooling fins can increase the outer surface of the housing, thus facilitating heat dissipation through the housing to the outside of the driveline assembly. The entire outer surface of the housing may carry cooling fins. The cooling fins may be arranged in rows and a constant or non-constant pitch may exist between two adjacent rows. These columns may or may not all have the same orientation. If appropriate, the same fin may extend firstly into one housing and secondly into the other housing.

In the illustrated embodiment, a cooling circuit 3 through which coolant flows is provided for distributing the coolant throughout the drivetrain assembly 1 . The coolant flowing through the cooling circuit 3 may be a very low viscosity oil. The kinematic viscosity value of this type of ultra-low viscosity oil at 40°C is less than 40, and the kinematic viscosity value at 100°C is less than 10. By using this type of ultra-low viscosity oil flowing throughout the driveline assembly via the cooling circuit 3, all components included in the driveline assembly are more efficiently lubricated and cooled with lower pressure drop. I can do it.

The cooling circuit 3 comprises a single inlet 31 and a single outlet 32 provided on the drivetrain assembly 1 . The inlet 31 can be connected to the oil pump 4 to control the flow of ultra-low viscosity oil supplied to the cooling circuit 3 to the required flow rate, and the outlet 32 can be connected to the heated oil discharged from the cooling circuit 3. It can be connected to a radiator 5 for cooling. Meanwhile, the radiator 5 can be connected to the oil pump 4 to transfer cooled oil into the drive train assembly 1 via the oil pump 4. In the illustrated embodiment, the oil pump 4 and the radiator 5 are located on the electric vehicle side 2. When the driveline assembly 1 is installed on an electric vehicle, the inlet 31 and the outlet 32 are in fluid communication with the oil pump 4 and the radiator 5, respectively, via several hoses 6 on the electric vehicle side 2, thereby The low viscosity oil can flow autonomously throughout the driveline assembly 1 for cooling and lubrication during operation.

In one embodiment, the radiator 5 may be integrated with the driveline assembly 1 to receive heated oil from the driveline assembly 1 and return cooled oil to the driveline assembly.

In one embodiment, the oil pump 4 may be an electric pump or a mechanical pump and may be integrated with the drivetrain assembly 1 , in particular mechanically integrated with the speed reducer 13 . The oil pump 4 can be a positive displacement pump to provide the required flow rate, in particular an accelerated flow rate. To be able to apply high oil pressure for cooling, positive displacement pumps are used instead of centrifugal pumps, and positive displacement pumps increase the heat dissipation capacity through heat sinks that draw heat from the switching devices.

In one embodiment, the cooling circuit 3 may comprise an oil reservoir (not shown) provided within the speed reducer 13, which oil reservoir is used to hold the required ultra-low viscosity oil therein. As a result, a minimum flow rate of cooling and lubricating oil within the drive train assembly 1 can be ensured.

Referring now to FIGS. 4A and 4B, a power switching device 17, such as an IGBT, may be cooled on one side by oil flowing in an oil distribution passage located inside one cooling plate 18 of the power inverter. The power switching device 17 may be double-sided cooled by oil flowing in two cooling plates 18, ie the power switching device and the cooling plate are formed as a sandwich structure.

In one embodiment, in a directly cooled power switching device 17, i.e., an IGBT module, the power switching device 17 is cooled directly with oil so that the thermal grease and the additional aluminum heat sink are removed so that the thermal resistance can be improved. Contact. Employing direct contact cooling has a limited increase in cost, which can be easily compensated for, for example, by the use of miniaturized oil-cooled motors that utilize oil cooling associated with the inverter.

In one embodiment, the power switching device 17 is controlled in full wave or DVPWM mode starting from a given RPM so that power dissipation from the IGBT can be reduced and allows the use of oil cooling.

With such a configuration, the electric motor 12 is cooled by oil, which greatly improves efficiency at high torques. Oil-cooled motors can be 5% more efficient in hot conditions than water-cooled motors. By limiting the heat dissipated by the cooling plate and oil, the current flowing through the IGBT can be significantly reduced.

Referring now to FIG. 2, an oil distribution passageway is located within the power inverter. Specifically, the oil distribution passageway is located within a cooling plate 18 disposed within the power inverter and is formed around the periphery and along the inner surface 181 of the cooling plate 18 . The periphery of the cooling plate 18 provides a groove 21 for a sealing connection with the cover 19, as shown in FIG. A supplemental heat transfer element is provided within the oil distribution passage to provide additional heat dissipation. As shown in the embodiment, the auxiliary heat transfer elements may be several metal spikes 16 provided by the cooling plate 18, in particular by the inner surface 181 of the cooling plate 18, the spikes 16 being oil-filled inward from the inner surface. It extends towards a cover 19 (as shown in Figure 3) used to enclose the distribution passage. The auxiliary heat transfer element is made of a heat dissipating material, for example aluminum. In one embodiment, metal spikes 16 may be filled with a high density of oil distribution passages. High density spikes are a significant burden on traditional centrifugal water pump circuits due to higher pressure drops, whereas positive displacement oil pumps hardly detect higher pressure drops. The metal spikes 16 can have circular and/or square cross-sections (not shown) or other shapes that help improve the oil flow F velocity. With the provision of an oil pump, oil flows through the distribution passages from one side of the cooling plate 18 to the other. The oil pump provides an accelerated flow rate to increase the speed of the oil flow F to increase heat dissipation.

Still referring to FIG. 2, at least one baffle 15 is provided within the oil distribution passageway to guide the flow of oil F through the oil distribution passageway. In the illustrated embodiment, two baffles 15 extend from two opposite edges of the cooling plate 18 so that the channels for the oil flow F can be formed as an "S" shape. However, it should be understood that the baffle 15 and spike 16 configurations described herein are merely examples. In other exemplary embodiments, the baffles 15 may be arranged in other configurations or orientations depending on different shapes of the cooling plate 18 to better improve the oil flow F.

Referring now to FIG. 3, an exemplary configuration of cooling plate 18 and corresponding cover 19 is shown. In conventional designs for covers, the spikes 16 are provided on the cooling plate 18 while the cover 19 may be a flat plate. In this design for the cover, both the cover 19 and the cooling plate 18 can be provided with spikes 16, the spikes provided by the cover 19 extending axially towards the cooling plate 18, while the spikes provided by the cooling plate The spikes extending axially towards the cover 19 such that the spikes from the cooling plate 18 and the cover 19 are spaced apart such that the flow path gap between the spikes 16 can be narrowed, thereby 16 to further enhance the cooling performance of the cooling plate 18. Even though the original water cooling circuit had a large number of spikes, this distribution of spikes on both sides allows oil to be used to reach a similar level of cooling as water.

Still referring to FIG. 3, when the cover 19 corresponds to the cooling plate 18, the baffle 15 is in sealing contact with the cover 19 surrounding the oil distribution passage, and in particular the sealing material 20 is in contact with the cover 19 in a sealing manner surrounding the oil distribution passage. 19 and one free end 151 of each baffle 15 . A sealing material 20 is also applied to the groove 21 provided by the periphery of the cooling plate 18 . Placing the sealing material on the cover connects the cover and the cooling plate in such a way as to avoid flow rate losses in the channels caused by gaps that allow the oil flow F to cross between the cover and the cooling plate. The gap between the two can be definitely eliminated. By having a sealing material on the cover, the number of spikes on the cooling plate can be increased, which is an essential factor for dissipating heat efficiently, but like the surrounding of classical method cooling In addition, if the encapsulant material has to be placed directly on the heat sink, the grooves take on a larger cross section and the number of spikes is reduced.

With the above configuration, a single fluid circuit for both cooling and lubrication of the driveline assembly is achieved. Moreover, compared to water cooling with a high spike density, only about 10% higher thermal resistance can be reached.

This specification is intended to disclose embodiments of the disclosure, including the best mode, and also includes implementation of embodiments of the disclosure, including the making and use of any devices or systems and implementation of any incorporated methods. Examples are used to enable those skilled in the art. The patentable scope of the embodiments described herein is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples include claims if they have structural elements that do not differ from the language of the claims, or if they include equivalent structural elements that do not materially differ from the language of the claims. is intended to be within the range of

Claims (11)

An integrated drivetrain assembly (1) for an electric vehicle, comprising:
an electric motor (12) comprising a rotor and a stator;
a power inverter (11) electrically connected to the electric motor (12) and configured to supply electrical energy to the stator;
a speed reducer (13) coupled to the electric motor (12) and configured to receive torque provided by the rotor;
one cooling circuit (3) with a single inlet (31) and a single outlet (32), said cooling circuit (3) for lubricating and cooling all components therein; The cooling circuit (3) is configured to distribute oil flowing throughout the integrated driveline assembly (1), the cooling circuit (3) cooling at least one power switching device (17) provided by the power inverter (11). an oil distribution passage disposed within a cooling plate (18) configured to a cooling circuit (3) provided, wherein a cover (19) corresponding to said cooling plate (18) is provided surrounding said oil distribution passage and in sealing contact with said at least one baffle (15); A drivetrain assembly comprising: Drivetrain assembly according to claim 1, wherein a sealing material (20) is provided between an inner surface (191) of said cover (19) and one end (151) of each of at least one of said baffles (15). . Drivetrain assembly according to claim 2, wherein a sealing material (20) is arranged on the inner surface (191) of the cover (19). The drivetrain assembly of claim 1, wherein a plurality of cooling spikes (16) are provided within the oil distribution passage, the cooling spikes (16) being arranged throughout the oil distribution passage in a high density. Drivetrain assembly according to claim 4, wherein the cooling spike (16) is provided on the cooling plate (18) and the cover (19). Drivetrain assembly according to claim 1, wherein the at least one power switching device (17) is arranged between two cooling plates (18) so that the power switching device can be cooled from both sides. Drivetrain assembly according to claim 1, wherein the oil distributed by the cooling circuit (3) is an ultra-low viscosity oil. further comprising an oil pump (4) configured to communicate with the inlet (31) for controlling the flow of oil through the cooling circuit (3);
The oil pump (4) is provided on the electric vehicle side (2) and when the integrated drivetrain assembly is installed in the electric vehicle, or the oil pump (4) is provided on the drivetrain assembly (1). connected to the inlet (31) when integrated with the
Drivetrain assembly according to claim 1, wherein the oil pump (4) is a positive displacement pump. the outlet (32) and the oil pump (4) for cooling the oil discharged from the driveline assembly (1) and transferring the cooled oil into the driveline assembly (1); The drivetrain assembly according to claim 8, further comprising a heat sink (5) configured to communicate between. Drivetrain assembly according to claim 9, wherein the radiator (5) is integrated with the drivetrain assembly (1) or provided on the electric vehicle side (2). An electric vehicle comprising the integrated drivetrain assembly (1) according to any one of claims 1 to 10.

Images