Thermal management system of electric automobile

Abstract

The invention relates to a thermal management system of an electric vehicle, and provides a system capable of preheating a battery even if a driving motor of the electric vehicle is not started. According to one embodiment, a heat management system (1) for an electric vehicle is provided with: a travel motor (12); an electric pump (30) that pressurizes and conveys the heat medium; a battery (2) that supplies power to the travel motor (12) and the electric pump (30); a first circulation circuit (20B) for the heat medium, the first circulation circuit (20B) passing through the travel motor (12) and the battery (2); and a control device (3). The control device (3) is configured to drive the electric pump (30) to pressurize and feed the heat medium to the first circulation circuit, heat the heat medium by the electric pump (30), and heat the battery (2) by the heat medium when a predetermined low-temperature condition is satisfied before the travel motor (12) is started.

Description

TECHNICAL FIELD

[0001] The technology disclosed in the present application relates to a thermal management system of an electric vehicle. BACKGROUND

[0002] Generally, a battery and a motor mounted on an electric vehicle have an appropriate temperature range for normal operation. In the past, a technology has been developed to bring the battery and the motor to a temperature in the appropriate range by thermal management. For example, in Japanese Patent Application Publication No. 2020-062964, a system is disclosed in which oil for lubricating a transfer drive is used for cooling and preheating (warm-up) of a battery. The system supplies the oil heated by heat generated by the transfer drive to the battery using an electric oil pump, thereby performing preheating of the battery.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT DOCUMENTS

[0005] Patent Document 1: Japanese Patent Application Publication No. 2020-062964 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] In the system disclosed in the above publication, since heat is discharged by the transfer drive, the transfer drive needs to be operated in order to preheat the battery, and the battery cannot be preheated before the electric vehicle is started. It is desirable to provide a system that can preheat a battery even when a travel motor is not started.

[0008] SOLUTION TO THE PROBLEM

[0009] One technical solution of the present technology is a thermal management system of an electric vehicle, wherein the thermal management system of the electric vehicle comprises: a travel motor; an electric pump that pressurizes and delivers a heat medium; a battery that supplies power to the travel motor and the electric pump; a first circulation circuit for the heat medium that passes through the travel motor and the battery; and a control device configured to, in a case where a predetermined low-temperature condition is satisfied before the travel motor is started, drive the electric pump to pressurize and deliver the heat medium to the first circulation circuit, heat the heat medium using the electric pump, and heat the battery using the heat medium. Thereby, preheating of the battery can be performed before the travel motor is started, and the battery performance can be improved even in a low-temperature environment.

[0010] According to the technical solution, the electric pump has an induction motor. Thereby, heat generated by both the stator and the rotor inside the induction motor can be used as a heat source for the heat medium.

[0011] According to the technical solution, the thermal management system of the electric automobile has: a cooler that cools the heat medium; a second circulation circuit for the heat medium that bypasses the battery via the travel motor and the cooler; and at least one switching valve that switches between the first circulation circuit that bypasses the cooler and the second circulation circuit, the travel motor has a neodymium magnet, and the control device is further configured to, in the case where a prescribed high-temperature condition is satisfied before the travel motor is started, switch to the second circulation circuit by means of the at least one switching valve, drive the electric pump to pressurizedly deliver the heat medium to the second circulation circuit, cool the heat medium with the cooler, and cool the travel motor with the heat medium. Thus, the neodymium magnet of the travel motor can be cooled before the travel motor is started, and the reduction in the performance of the travel motor in a high-temperature environment can be suppressed.

[0012] According to the technical solution, the control device is further configured to predict the start timing of the travel motor on the basis of information acquired from a device possessed by a user of the electric automobile. Thus, the execution of preheating and cooling before the electric automobile is started can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is a diagram that shows a thermal management system in a state in which oil flows in a circulation circuit that passes through an electric drive axle, a battery, and an oil cooler, as one embodiment.

[0014] Figure 2 is a diagram that shows a thermal management system in a state in which oil flows in a circulation circuit that bypasses an oil cooler via an electric drive axle and a battery.

[0015] Figure 3 is a diagram that shows a thermal management system in a state in which oil flows in a circulation circuit that bypasses a battery via an electric drive axle and an oil cooler.

[0016] BRIEF DESCRIPTION OF REFERENCE NUMERALS

[0017] 1, thermal management system; 2, battery; 3, control device; 10, electric drive axle; 11, transmission; 12, travel motor; 13, inverter; 20A, 20B, 20C, circulation circuit; 21, common passage; 22, passage through battery; 23, passage bypassing battery; 24, passage connecting battery and oil cooler; 25, passage through oil cooler; 26, passage bypassing oil cooler; 27, 28, switching valve; 30, electric oil pump; 31, pump motor; 32, pump portion; 33, housing; 34, control circuit substrate; 35, stator; 36, rotor and outer gear; 37, inner gear; 40, oil cooler; 50, smart device; 51, network. DETAILED DESCRIPTION

[0018] [Heat management system]

[0019] Figure 1 A heat management system 1 for a battery 2 and an electric drive axle 10 of an electric vehicle (a battery electric vehicle, which is a narrow sense of an electric vehicle without an engine) is shown as one embodiment.

[0020] The electric vehicle is provided with the battery 2 and the electric drive axle 10. The battery 2 is generally constituted by a plurality of secondary battery cells which are chargeable. The electric drive axle 10 is generally provided with an inverter 13, a travel motor 12, and a transmission 11. The inverter 13 controls rotation of the travel motor 12 using electric power of the battery 2. Rotational power of the travel motor 12 is decelerated and shifted by the transmission 11, and is transmitted to a wheel via a drive shaft. The travel motor 12 can be provided, for example, as a motor using a neodymium magnet.

[0021] The heat management system 1 is provided with at least one circulation circuit for circulating a heat medium such as oil inside a housing of the electric drive axle 10. The heat management system 1 is provided with an electric oil pump 30 which pressurizes and delivers oil to the circulation circuit using electric power of the battery 2. The oil at least performs cooling of the travel motor 12, and can also perform lubrication of the transmission 11. The electric oil pump 30 can be provided inside the same housing as the electric drive axle 10, or can be provided independently from the electric drive axle 10.

[0022] In the heat management system 1, an oil cooler 40 which cools oil by heat exchange with cooling water or air can be provided, for example. The heat management system 1 is provided with a circulation circuit 20A of oil via the electric drive axle 10, the battery 2, and the oil cooler 40. This circulation circuit 20A can be constituted by a common passage 21 through the electric drive axle 10, a passage 22 through the battery 2, a passage 25 via the oil cooler 40, and a passage 24 which connects between them. Although not shown, in the case of using cooling water, for example, the cooling water can be made to circulate via the oil cooler 40 and a radiator provided in the vehicle, and the cooling water which has been heated in the oil cooler 40 can be radiated in the radiator.

[0023] When the electric vehicle is traveling, both the electric drive axle 10 and the battery 2 have a tendency to become high temperature due to heat generation. In this case, by pressurizing and delivering oil to the circulation circuit 20A via the electric drive axle 10, the battery 2, and the oil cooler 40, the battery 2 and the travel motor 12 are cooled by the oil. At the same time, the electric oil pump 30 is also cooled, and the transmission 11 is lubricated. The oil is cooled in the oil cooler 40 by heat exchange with cooling water or air.

[0024] As Figure 2As shown, the thermal management system 1 is provided with a circulation circuit 20B of oil that bypasses the oil cooler 40 via the electric drive axle 10 and the battery 2. This circulation circuit 20B can be constituted, for example, by a common passage 21 through the electric drive axle 10, a passage 22 through the battery 2, and a passage 26 that bypasses the oil cooler 40. On the upstream side of the oil cooler 40, an electrically driven switching valve 28 is provided that switches between the passage through the oil cooler 40 and the passage that bypasses the oil cooler 40.

[0025] The thermal management system 1 is provided with a circulation circuit 20C of oil that bypasses the battery 2 via the electric drive axle 10 and the oil cooler 40. This circulation circuit 20C can be constituted, for example, by the common passage 21 through the electric drive axle 10, a passage 23 that bypasses the battery 2, and a passage 25 via the oil cooler 40. On the upstream side of the battery 2, another electrically driven switching valve 27 is provided that switches between the passage through the battery 2 and the passage that bypasses the battery 2.

[0026] [Electric oil pump]

[0027] As Figure 1 As shown schematically, the electric oil pump 30 is provided with a pump motor 31, a control circuit substrate 34, and a pump portion 32. The pump motor 31 is controlled by the control circuit substrate 34 and drives the pump portion 32. As one embodiment, the pump portion 32 can be, for example, an internal gear pump. The internal gear pump has an outer (internal tooth) gear and an inner (external tooth) gear that mesh with each other, and by driving either gear, oil is pressurized and delivered through between the outer gear 36 and the inner gear 37.

[0028] The pump motor 31 has a stator 35 and a rotor 36. The electric oil pump 30 can be configured so that oil can be pressurized and delivered even if it does not pass through a narrow air gap between the stator 35 and the rotor 36. For example, the suction port and the discharge port formed in the housing 33 of the electric oil pump 30 can be disposed on the same side of the outer gear 36 and the inner gear 37. By being configured in this way, the pressure loss of the oil can be reduced. The pump motor 31 can be configured, for example, as an axial gap motor.

[0029] As one embodiment, the pump motor 31 can be configured as an induction motor. By this, not only the coil of the stator 35 is heated, but also the electrically conductive body of the rotor 36 that flows with induced current is heated, so the oil is efficiently heated at low temperatures. In addition, the induction motor does not need to use a high-priced magnet for the rotor 36, so the cost can be reduced.

[0030] When using an induction motor, for example, by arranging a conductor of an appropriate shape on the outer gear 36 of the pump section 32, it is possible to also function as the rotor 36 of the pump motor 31. The outer gear 36 is driven by the induction motor, and the inner gear 37 rotates together with the outer gear 36 to pressurize and deliver oil. With such a structure, the shaft and bearings connecting the rotor 36 and the outer gear 36 can be eliminated, simplifying the construction. Furthermore, even with the above-described structure that allows the electric oil pump 30 to pass through the narrow air gap between the stator 35 and the rotor 36, the oil can be heated by the induced current generated in the rotor 36 causing the outer gear 36 to heat up itself.

[0031] [Control Device]

[0032] The thermal management system 1 includes a control device 3. The control device 3 includes at least one storage device (memory or recording medium) and at least one processing device (processor). By executing a program stored in the storage device (memory) through the processing device (processor), various functions, including the thermal management disclosed in this application, are implemented. The control device 3 is connected to actuators such as sensors, motors, and switching valves via communication components such as communication lines or wireless connections. Specifically, the control device 3 can be configured as a central computer with a vehicle operating system (OS) or at least one electronic control unit (ECU), domain control unit (DCU), or zone control unit (ZCU).

[0033] [Cold start situation]

[0034] like Figure 2 As shown, when the system is in a low-temperature state before starting the driving motor 12, such as in winter or at night, the control device 3 performs a heating (preheating) operation using the heat from the electric oil pump 30 to heat the oil and battery 2. Specifically, when the specified low-temperature conditions are met before starting the driving motor 12, the circulation loop 20B bypasses the oil cooler 40 via the battery 2. Then, the electric oil pump 30 is activated to circulate the oil. The oil temperature rises due to the heat generated by the pump motor 31 (coil current, induced current) of the electric oil pump 30, and the kinematic viscosity decreases. As a result, the starting load of the driving motor 12 is reduced, and power consumption can be suppressed. On the other hand, the battery 2 is preheated, thereby suppressing the voltage drop of the battery cells and improving the performance of the battery 2 when the driving motor 12 starts. The specified low-temperature conditions can be, for example, set to a situation where any one of the outside air temperature, the battery 2 temperature, or the driving motor 12 temperature is lower than a specified temperature. Although not shown, the control device 3 can obtain these temperatures from temperature sensors installed in locations exposed to outside air, inside the battery 2 housing, and inside the driving motor 12 housing, respectively.

[0035] [High-temperature start-up situation]

[0036] like Figure 3 As shown, when the system is at a high temperature before the driving motor 12 is started, such as in summer or during the day, the control device 3 performs an operation to cool the oil and the driving motor 12 using the oil cooler 40. For example, if the specified high temperature conditions are met before the driving motor 12 is started, the circulation loop 20C bypasses the battery 2 via the oil cooler 40. Then, the driving motor 12 is cooled by circulating the oil by operating the electric oil pump 30. When the driving motor 12 is started, the magnet is subjected to a large external magnetic field due to the large current. When the magnet is subjected to a magnetic field exceeding its coercivity, irreversible demagnetization can occur. In particular, for neodymium magnets, the higher the temperature, the lower the coercivity. When neodymium magnets are used in the driving motor 12, pre-cooling the neodymium magnets with oil via the oil cooler 40 as described above can suppress the occurrence of demagnetization. In addition, it can also reduce the amount of expensive dysprosium that is usually added to increase coercivity, thereby reducing costs. The specified high temperature condition can be set to a situation where any one of the following conditions is higher than the specified temperature: the outside air temperature, the battery 2 temperature, or the driving motor 12 temperature.

[0037] [Control of the electric oil pump]

[0038] The control device 3 can determine the operating parameters of the electric oil pump 30, such as the flow rate, operating time, and termination time, so that one or both of the drive motor 12 and the battery 2 are at their optimal temperature before the drive motor 12 is started. For example, the control device 3 can monitor the temperature of the battery 2 and the temperature of the drive motor 12, and determine and correct the operating parameters of the electric oil pump 30 so that the battery 2 and the drive motor 12 are at their optimal temperature range at or before startup.

[0039] The determination of whether the specified low-temperature and high-temperature conditions are met needs to be performed before the drive motor 12 is started. Therefore, the control device 3 can, for example, predict the next start time of the drive motor 12 based on the vehicle start time (i.e., the start time of the drive motor 12) recorded by the control device 3 each time. Furthermore, for example, the above determination can be performed well before the predicted start time. Additionally, the start time of the drive motor 12 can be predicted or corrected based on the timing of specific user actions related to the vehicle, such as remote operation of the vehicle key, the approach of the vehicle key (carrying the vehicle key) to the vehicle, the opening and closing of the doors, and sitting in the driver's seat.

[0040] like Figures 1-3As shown, the control device 3 can also utilize information acquired from a computer device possessed by the vehicle user to make the prediction of the start timing of the travel motor 12 or to correct the predicted timing. The computer device is, for example, a smart device 50, specifically, a smartphone, a tablet, a wearable device (e.g., a smart watch), or the like possessed or carried by the vehicle user. The control device 3 has a communication interface configured to be able to acquire information related to the action of the vehicle user from a prescribed application installed in the smart device 50 via a network 51 such as the Internet. The information related to the action of the vehicle user includes, for example, the start of the smart device 50, a specific operation to the smart device 50 such as a screen display, the position of the smart device 50 (carried by the vehicle user) (e.g., position information acquired by the smart device 50 via a GPS satellite, a communication base station, or the like), and the like. The control device 3 can make the prediction of the start timing of the travel motor 12 or correct the predicted timing based on these pieces of information. The control device 3 can also be configured to be able to acquire an active standby instruction input by the vehicle user using the smart device 50 via the network 51. In this case, the control device 3 can, for example, immediately perform the judgment of whether the prescribed low-temperature condition or high-temperature condition is satisfied based on the standby instruction.

[0041] [Low-temperature rapid charging]

[0042] In the case where the rapid charging with the battery 2 is performed before the start, the control device 3 can also perform the operation of heating the oil using the heat of the battery 2 in the case where the prescribed low-temperature condition is established. Specifically, the circulation circuit 20B is switched to bypass the oil cooler 40 via the battery 2 before the start Figure 2 . Then, the oil is circulated using the electric oil pump 30. Thereby, the oil is temperature-increased due to the heat from the battery 2 in the rapid charging, and the kinematic viscosity is decreased. Thereby, it is possible to reduce the start load of the travel motor 12.

[0043] The above describes various embodiments, but the present technology is not limited to these embodiments, and various substitutions, modifications, and changes can be made without departing from the gist of the present technology, if they are made by those skilled in the art.

Claims

1. A thermal management system for an electric vehicle, wherein, The electric vehicle's thermal management system includes: Motor for driving; Electric pumps are used to pressurize and transport hot media. A battery that supplies power to the driving motor and the electric pump; A first circulation loop for supplying the heat medium, which passes through the driving motor and the battery; as well as Control device, The control device is configured to, under the condition that a specified low temperature is met before the driving motor is started, drive the electric pump to pressurize and deliver the heat medium to the first circulation loop, use the electric pump to heat the heat medium, and use the heat medium to heat the battery.

2. The thermal management system for electric vehicles according to claim 1, wherein, The electric pump has an induction motor.

3. The thermal management system for electric vehicles according to claim 1 or 2, wherein, The electric vehicle's thermal management system includes: A cooler that cools the heat medium; A second circulation loop for the heat transfer medium bypasses the battery via the driving motor and the cooler; and At least one switching valve that switches between the first circulation loop and the second circulation loop. The first circulation loop bypasses the cooler. The driving motor has neodymium magnets. The control device is further configured to, when a specified high temperature condition is met before the driving motor is started, switch to the second circulation loop by means of the at least one switching valve, drive the electric pump to pressurize and deliver the heat medium to the second circulation loop, cool the heat medium using the cooler, and cool the driving motor using the heat medium.

4. The thermal management system for electric vehicles according to claim 1 or 2, wherein, The control device is further configured to predict the start-up time of the driving motor based on information obtained from the device owned by the user of the electric vehicle.

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