Electric vehicle temperature control system

Abstract

This electric vehicle temperature control system uses the same CO2 refrigerant as the cabin air conditioning system, achieving overall system weight reduction and efficiency while providing highly responsive battery temperature control. [Solution] The electric vehicle temperature control system 100 includes compressors 1a and 1b for compressing CO2 refrigerant, a heat exchanger 2 for cooling the refrigerant, a cooling expansion valve V1a for expanding the refrigerant, a refrigerant passage 13b for supplying refrigerant to the air conditioner 5 when the air conditioner 5 is being cooled, a refrigerant passage 12 for supplying refrigerant to the motor when the motor 4 is being cooled, a battery refrigerant expansion valve V4a for expanding the refrigerant and injecting it into the battery case 6a, a refrigerant passage 14 and a refrigerant path switching valve V2 for supplying the refrigerant after it has cooled the motor to the battery refrigerant expansion valve when the motor and the battery 6 are being cooled, and refrigerant passages 14, 15, 17, and 18 for supplying the refrigerant that has passed through the air conditioner, motor, and battery to the compressor.

Description

Technical Field

[0001] The present invention relates to a temperature regulation system for an electric vehicle.

Background Art

[0002] Conventionally, air conditioning systems having a thermal cycle circuit that operates using a refrigerant containing CO2 (hereinafter appropriately referred to as "CO2 refrigerant") are known. In addition, a technology that thermally couples the thermal cycle circuit of an in-cabin air conditioning system of an electric vehicle to a battery to cool or heat the battery (for example, Patent Document 1), and a cooling system that circulates low-temperature CO2 inside the individually sealed vehicle drive motor, inverter and battery in a cooling unit for direct cooling (for example, Patent Document 2) have been studied.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of Invention

Problems to be Solved by the Invention

[0004] In recent years, the adoption of CO2 refrigerant in in-cabin air conditioning systems has also been studied. In this case, it is conceivable that the CO2 refrigerant used in the thermal cycle circuit of the in-cabin air conditioning system is also used for temperature regulation of the motor and the battery.

[0005] However, in general, the pressure of the CO2 refrigerant, which is reduced to a low temperature by the expansion valve in the thermal cycle circuit of an air conditioning system, is very high, around 5 MPa. If such high-pressure CO2 refrigerant is flowed around the battery cells to directly cool them, it becomes necessary to increase the strength of the battery case and cell structure, leading to an increase in battery weight and manufacturing costs. On the other hand, if high-pressure CO2 refrigerant is flowed through a heat exchanger installed on the outside of the battery case to indirectly cool the cells inside the battery via the heat exchanger, the responsiveness of temperature control is lower compared to the direct cooling described above. As a result, the temperature fluctuation range of the battery increases, and battery degradation due to thermal cycling is more likely to occur.

[0006] This invention was made to solve these problems, and aims to provide a temperature control system for electric vehicles that can control the battery temperature with high responsiveness while reducing the overall weight and efficiency of the system by using the same CO2 refrigerant as the air conditioning system used in the vehicle cabin. [Means for solving the problem]

[0007] To solve the above-mentioned problems, the present invention provides a temperature control system for an electric vehicle comprising an air conditioning unit for performing air conditioning, a drive motor, and a battery with cells housed inside a battery case, comprising: a compressor for compressing a refrigerant containing CO2; a heat exchanger for cooling the refrigerant compressed by the compressor; a first expansion valve for expanding the refrigerant cooled by the heat exchanger; an air conditioning cooling path for supplying the refrigerant expanded by the first expansion valve to the air conditioning unit when the air conditioning unit is being cooled; a motor cooling path for supplying the refrigerant expanded by the first expansion valve to the motor when the motor is being cooled; a second expansion valve for expanding the refrigerant and injecting it into the battery case; a battery cooling path for supplying the refrigerant after cooling the motor to the second expansion valve when the motor and battery are being cooled; and a recovery path for supplying the refrigerant that has passed through the air conditioning unit, the refrigerant that has passed through the motor, and the refrigerant that has passed through the battery to the compressor.

[0008] With the present invention configured in this way, the cooling of the air conditioning unit, the motor, and the battery are performed by a common refrigerant containing CO2, making the overall temperature control system more compact. Furthermore, when cooling the motor and the battery, the refrigerant used to cool the motor is supplied to a second expansion valve, where it is further expanded and injected into the battery case. This allows the cells to be directly cooled by the refrigerant while maintaining the same level of strength as conventional systems for the battery cells and case structure. As a result, the battery temperature can be controlled with high responsiveness without increasing the battery weight or manufacturing costs. In addition, there is no need to provide a separate heat exchanger solely for battery cooling, which allows for weight reduction and increased efficiency of the entire temperature control system. Therefore, even when applied to lightweight sports cars, it can provide excellent handling and acceleration, enhancing the joy of driving.

[0009] In the present invention, preferably, the compressor includes a first compressor that compresses the refrigerant that has passed through the battery, and a second compressor that compresses the refrigerant that has passed through the air conditioning unit and the refrigerant that has passed through the motor, wherein the second compressor further compresses the refrigerant that has been compressed by the first compressor when the motor and the battery are being cooled.

[0010] With the present invention configured in this way, the refrigerant compressed by the first compressor after passing through the battery, the refrigerant that has passed through the air conditioning unit, and the refrigerant that has passed through the motor can all be compressed by the second compressor. Therefore, a common second compressor can be used for compressing the refrigerant used to cool the air conditioning unit, motor, and battery, making the overall temperature control system more compact.

[0011] In the present invention, preferably, the temperature control system for an electric vehicle includes a battery heating path that supplies a refrigerant compressed by a first compressor to a second expansion valve when the battery is heated.

[0012] With the present invention configured in this way, the cells can be directly heated by the refrigerant by expanding the high-temperature refrigerant compressed by the first compressor into the inside of the battery case through the second expansion valve. This makes it possible to control the temperature of the battery with high responsiveness without increasing the weight of the battery or raising manufacturing costs.

[0013] In the present invention, preferably, the second expansion valve includes a common rail for storing refrigerant and an injector for injecting the refrigerant stored in the common rail into the inside of the battery case.

[0014] According to the present invention configured in this manner, the necessary amount of refrigerant corresponding to the heat generation and temperature of the battery can be precisely injected from the injector into the battery case at an appropriate pressure. This suppresses temperature fluctuations in the battery cells and reduces battery degradation due to thermal cycling.

[0015] In the present invention, preferably, the temperature control system of an electric vehicle includes an air conditioning heating path that supplies a refrigerant compressed by a compressor to the air conditioning unit when the air conditioning unit is being heated.

[0016] According to the present invention configured in this manner, the air conditioning unit can be heated by supplying a high-temperature, high-pressure refrigerant compressed by a compressor to the air conditioning unit via an air conditioning heating path. [Effects of the Invention]

[0017] According to the electric vehicle temperature control system of the present invention, by using the same CO2 refrigerant as the one used for air conditioning in the passenger compartment, it is possible to lighten and improve the overall efficiency of the system while controlling the battery temperature with high responsiveness. [Brief explanation of the drawing]

[0018] [Figure 1] This is a schematic diagram of a vehicle to which a temperature control system for electric vehicles according to an embodiment of the present invention is applied. [Figure 2]This is a schematic configuration diagram of a temperature regulation system for an electric vehicle according to an embodiment of the present invention. [Figure 3] This is a block diagram showing the electrical configuration of the temperature regulation system for an electric vehicle according to the embodiment of the present invention. [Figure 4] This is a flowchart of the control executed by the temperature regulation system for an electric vehicle according to the embodiment of the present invention. [Figure 5] This is a table showing air conditioning-battery cooperative control patterns corresponding to combinations of an air conditioning request and a battery temperature regulation request for the temperature regulation system for an electric vehicle according to the embodiment of the present invention. [Figure 6] This is an explanatory diagram showing the P-H diagrams and P-T diagrams of the thermal cycles of the motor, air conditioner and battery, and the flow of refrigerant in the air conditioning-battery cooperative control pattern 1-a of the temperature regulation system for an electric vehicle according to the embodiment of the present invention. [Figure 7] This is an explanatory diagram showing the P-H diagrams and P-T diagrams of the thermal cycles of the motor, air conditioner and battery, and the flow of refrigerant in the air conditioning-battery cooperative control pattern 2-a of the temperature regulation system for an electric vehicle according to the embodiment of the present invention. [Figure 8] This is an explanatory diagram showing the P-H diagrams and P-T diagrams of the thermal cycles of the motor, air conditioner and battery, and the flow of refrigerant in the air conditioning-battery cooperative control pattern 2-b of the temperature regulation system for an electric vehicle according to the embodiment of the present invention. [Figure 9] This is an explanatory diagram showing the P-H diagrams and P-T diagrams of the thermal cycles of the motor and battery, and the flow of refrigerant in the air conditioning-battery cooperative control pattern 3-a of the temperature regulation system for an electric vehicle according to the embodiment of the present invention. [Figure 10] This is an explanatory diagram showing the P-H diagrams and P-T diagrams of the thermal cycles of the motor and battery, and the flow of refrigerant in the air conditioning-battery cooperative control pattern 3-b of the temperature regulation system for an electric vehicle according to the embodiment of the present invention. [Figure 11] This is an explanatory diagram showing the P-H diagrams and P-T diagrams of the thermal cycles of the motor, air conditioner and battery, and the flow of refrigerant in the air conditioning-battery cooperative control pattern 4-a of the temperature regulation system for an electric vehicle according to the embodiment of the present invention. [Figure 12]This is an explanatory diagram showing the PH diagram and PT diagram of the thermal cycle of the motor, air conditioner, and battery, and the flow of the refrigerant, in the air conditioning / battery coordinated control pattern 4-b of the temperature control system for an electric vehicle according to an embodiment of the present invention. [Modes for carrying out the invention]

[0019] A temperature control system for an electric vehicle according to an embodiment of the present invention will be described below with reference to the attached drawings.

[0020] [Overall structure] First, with reference to Figure 1, the overall configuration of the electric vehicle temperature control system according to this embodiment will be described. Figure 1 is a schematic diagram of a vehicle to which the electric vehicle temperature control system according to this embodiment is applied.

[0021] As shown in Figure 1, the electric vehicle 200 includes a temperature control system 100 having a thermal cycle circuit that operates with a refrigerant containing CO2, a motor 4 for driving the electric vehicle 200, an air conditioner (air conditioning unit) 5 for air conditioning inside the electric vehicle 200, and a battery 6 for supplying power to the motor 4. The temperature control system 100 also mainly includes a high-pressure compressor 1a and a low-pressure compressor 1b for compressing the refrigerant, and a heat exchanger 2 for cooling the refrigerant compressed by the high-pressure compressor 1a.

[0022] The temperature control system 100 circulates a CO2 refrigerant (hereinafter sometimes simply referred to as "refrigerant") as a natural refrigerant. Typically, the CO2 refrigerant is a refrigerant containing CO2 with refrigerant oil such as PAG or additives. Because such a CO2 refrigerant is used, the high-pressure compressor 1a is configured to compress the refrigerant to a very high pressure (e.g., 11 MPa). The motor 4 uses the refrigerant compressed by the high-pressure compressor 1a and cooled by the heat exchanger 2 to cool the rotor and stator. Furthermore, the motor 4 is configured to lubricate the sliding bearings supporting the rotating shaft with the refrigerant. The refrigerant used to cool the motor 4 may then be used to cool the battery 6. In addition, the refrigerant compressed by the high-pressure compressor 1a or the refrigerant cooled by the heat exchanger 2 after compression is used for air conditioning in the air conditioner 5. In addition, the refrigerant compressed by the low-pressure compressor 1b may be used to raise the temperature of the battery 6.

[0023] [Temperature control system configuration] Next, the temperature control system 100 according to this embodiment will be described in detail with reference to Figure 2. Figure 2 is a schematic diagram of the temperature control system 100 according to this embodiment.

[0024] The temperature control system 100 comprises a thermal cycle circuit that circulates the CO2 refrigerant described above, and in addition to the high-pressure compressor 1a, low-pressure compressor 1b and heat exchanger 2 described above, it includes a reservoir tank 7 for temporarily storing the refrigerant so that the refrigerant can circulate stably within the thermal cycle circuit, refrigerant passages 11 to 18 through which the refrigerant flows, a cooling expansion valve V1a (first expansion valve) for expanding and depressurizing the refrigerant, a temperature rise valve V1b for switching the passage of high-temperature, high-pressure refrigerant, a refrigerant path switching valve V2 for switching the path of the refrigerant used to cool the motor 4, a refrigerant path switching valve V3 for switching the path of the refrigerant that has left the battery 6, and battery refrigerant expansion valves V4a and V4b for expanding and depressurizing the refrigerant and injecting it into the battery 6.

[0025] The high-pressure compressor 1a (second compressor) compresses the refrigerant that has passed through the motor 4 or air conditioner 5 and is stored in the reservoir tank 7, or that has passed through the battery 6 and been compressed by the low-pressure compressor 1b and stored in the reservoir tank 7. The low-pressure compressor 1b (first compressor) compresses the refrigerant that has passed through the battery 6. The high-pressure compressor 1a increases the refrigerant pressure P2 to pressure P1 (pressure P1 > pressure P2), and the low-pressure compressor 1b increases the refrigerant pressure P3 to pressure P2 (pressure P2 > pressure P3). In one example, pressure P1 is approximately 11 MPa, pressure P2 is approximately 5 MPa or 0.3 MPa, and pressure P3 is approximately 0.1 MPa.

[0026] The heat exchanger 2 cools the refrigerant compressed by the high-pressure compressor 1a.

[0027] Motor 4 is cooled by the temperature control system 100. Specifically, the refrigerant is compressed by the high-pressure compressor 1a, cooled through the refrigerant passage 11 and heat exchanger 2, and then expanded by the cooling expansion valve V1a to a low temperature before being supplied to motor 4 from the refrigerant passage 12 (motor cooling path). The refrigerant supplied to motor 4 cools motor 4 by absorbing heat as it passes through the internal structure 4a of motor 4, such as between the rotor and stator, and the bearings supporting the rotating shaft connected to the rotor, and returns to the high-pressure compressor 1a through the refrigerant passage 14, reservoir tank 7, and refrigerant passage 18 (recovery path), where it is compressed again. Also, when cooling battery 6, the refrigerant that has passed through motor 4 is supplied to battery refrigerant expansion valve V4a through the refrigerant passage 14 and refrigerant path switching valve V2 (battery cooling path), and is injected into the inside of battery 6 from battery refrigerant expansion valve V4a.

[0028] The air conditioner 5 is cooled or heated by the temperature control system 100. When the air conditioner 5 is being cooled, the refrigerant is compressed by the high-pressure compressor 1a, cooled through the refrigerant passage 11 and heat exchanger 2, and then expanded by the cooling expansion valve V1a to a temperature lower than the air in the passenger compartment, and supplied to the air conditioner 5 from the refrigerant passage 13b (air conditioning cooling path). The refrigerant supplied to the air conditioner 5 cools the air flowing into the passenger compartment by absorbing heat as it passes through the passenger compartment heat exchanger of the air conditioner 5, and returns to the high-pressure compressor 1a through the refrigerant passage 15, reservoir tank 7 and refrigerant passage 18 (recovery path), where it is compressed again.

[0029] When the air conditioner 5 is heating, the refrigerant is compressed by the high-pressure compressor 1a and expands by the temperature rise valve V1b, but the refrigerant, which is hotter than the air in the passenger compartment, is supplied to the air conditioner 5 from the refrigerant passage 13a (air conditioning heating path). The refrigerant supplied to the air conditioner 5 heats the air flowing into the passenger compartment by releasing heat as it passes through the passenger compartment heat exchanger of the air conditioner 5, and returns to the high-pressure compressor 1a through the refrigerant passage 15, reservoir tank 7 and refrigerant passage 18 (recovery path), where it is compressed again.

[0030] In this embodiment, the battery 6 comprises a battery case 6a and cells 6b housed inside the battery case 6a. The battery case 6a is sealed, and refrigerant is supplied to the inside of the battery case 6a via a battery refrigerant expansion valve V4a or V4b, and the refrigerant is discharged from the battery case 6a via a refrigerant passage 16. The battery refrigerant expansion valves V4a and V4b (second expansion valves) expand the refrigerant and inject it into the inside of the battery case 6a. The battery refrigerant expansion valves V4a and V4b are preferably capable of controlling the pressure and flow rate of the injected refrigerant, for example, a common rail and an injector are used. The common rail stores the refrigerant supplied via a refrigerant path switching valve V2 or V3, and the injector injects the refrigerant stored in the common rail into the inside of the battery case 6a. In this case, the battery refrigerant expansion valves V4a and V4b may be configured to share one common rail and injector.

[0031] During the cooling of the battery 6, the refrigerant remaining after cooling the motor 4 is injected into the battery case 6a by the battery refrigerant expansion valve V4a via the refrigerant passage 14 and the refrigerant path switching valve V2 (battery cooling path). At this time, the refrigerant expands and becomes colder than the cells 6b. The refrigerant injected into the battery case 6a cools the cells 6b by absorbing heat as it flows around them, and then exits the battery case 6a through the refrigerant passage 16. In this way, the cells 6b are directly cooled by the refrigerant. Subsequently, the refrigerant is compressed by the low-pressure compressor 1b and returns to the high-pressure compressor 1a through the refrigerant path switching valve V3, refrigerant passage 17, reservoir tank 7, and refrigerant passage 18 (recovery path), where it is compressed again.

[0032] Furthermore, when the battery 6 is heated, no refrigerant is supplied from the motor 4. In this case, the refrigerant released from the battery case 6a passes through the refrigerant passage 16, is compressed by the low-pressure compressor 1b, and is injected into the battery case 6a by the battery refrigerant expansion valve V4b via the refrigerant path switching valve V3 (battery heating path). At this time, the refrigerant expands but becomes hotter than the cell 6b, and the refrigerant injected into the battery case 6a heats the cell 6b by dissipating heat as it flows around the cell 6b, returns to the low-pressure compressor 1b through the refrigerant passage 16 and is compressed again. In this way, the cell 6b is directly heated by the refrigerant.

[0033] Next, the electrical configuration of the temperature control system 100 according to this embodiment will be described with reference to Figures 2 and 3. Figure 3 is a block diagram showing the electrical configuration of the temperature control system 100 according to this embodiment.

[0034] As shown in Figure 3, the temperature control system 100 has a control device 40 configured to perform various controls in the system. The control device 40 is composed of a computer that includes one or more processors 40a (typically CPUs) and a memory 40b such as ROM or RAM that stores various programs (including basic control programs such as an OS and application programs launched on the OS to realize specific functions) and various data that are interpreted and executed on the processors 40a.

[0035] Furthermore, the temperature control system 100 includes a refrigerant temperature sensor 31 for detecting the temperature of the refrigerant flowing through the refrigerant passages 11 to 18, a refrigerant pressure sensor 32 for detecting the pressure of the refrigerant, a battery temperature sensor 33 for detecting the temperature of the battery 6, a motor temperature sensor 34 for detecting the temperature of the motor 4, an interior / exterior air temperature sensor 35 for detecting the ambient temperature inside and outside the electric vehicle 200, and an air conditioning switch 36 for receiving operation input to the air conditioner 5. Multiple refrigerant temperature sensors 31 and refrigerant pressure sensors 32 can be installed at any point in the refrigerant passages 11 to 18.

[0036] The control device 40 outputs control signals to the high-pressure compressor 1a, low-pressure compressor 1b, cooling expansion valve V1a, heating valve V1b, refrigerant path switching valves V2 and V3, and battery refrigerant expansion valves V4a and V4b based on signals input from the sensors 31 to 35 and the air conditioning switch 36, and controls them accordingly.

[0037] [control] Next, with reference to Figures 4 and 5, the control performed by the control device 40 in this embodiment will be described. Figure 4 is a flowchart of the control performed by the temperature control system 100 of the electric vehicle 200 according to an embodiment of the present invention, and Figure 5 is a table showing the air conditioning / battery coordinated control pattern according to the combination of air conditioning requests and battery temperature control requests of the temperature control system 100 of the electric vehicle 200.

[0038] The control shown in Figure 4 is repeatedly executed at predetermined intervals by the control device 40 during the operation of the temperature control system 100. Specifically, the processor 40a within the control device 40 reads a program stored in the memory 40b and executes the program, thereby realizing the control shown in the flowchart of Figure 4.

[0039] When control is initiated, in step S1, the control device 40 acquires various information such as the detected values ​​detected by the sensors 31 to 35 and the operation values ​​input to the air conditioning switch 36.

[0040] Next, in step S2, the control device 40 obtains a heating or cooling request for the air conditioner 5, i.e., a required value for the cooling or heating capacity of the air conditioner 5 (for example, the flow rate of refrigerant supplied to the air conditioner 5), based on the information obtained in step S1. For example, the required value for the cooling or heating capacity of the air conditioner 5 is obtained according to the difference between the temperature set by the air conditioning switch 36 and the temperature inside the vehicle.

[0041] Next, in step S3, the control device 40 obtains a cooling request for the motor 4, i.e., a required cooling capacity for the motor 4 (for example, the flow rate of the refrigerant supplied to the motor 4), based on the information obtained in step S1. For example, the required cooling capacity for the motor 4 is obtained according to the difference between a preset reference temperature and the temperature of the motor 4 detected by the motor temperature sensor 34.

[0042] Next, in step S4, the control device 40 obtains a temperature control request for the battery 6, i.e., a request for cooling or heating the battery 6, based on the information obtained in step S1. Specifically, in situations where cooling of the battery 6 is necessary, for example, when power is supplied from the battery 6 to drive the motor 4, or when regenerative power is supplied from the motor 4 to the battery 6, and a temperature rise of the battery 6 is predicted, the control device 40 obtains a required cooling capacity for the battery 6 (for example, the amount of refrigerant injected from the battery refrigerant expansion valve V4a) according to the magnitude of the power supplied from the battery 6 or the magnitude of the regenerative power input to the battery 6. Also, in situations where heating of the battery 6 is necessary, for example, when the electric vehicle 200 needs to raise the temperature of the battery 6 to a charging temperature higher than ambient temperature in order to perform charging while stationary, or when the temperature of the battery 6 detected by the battery temperature sensor 33 during the operation of the electric vehicle 200 is lower than a preset reference temperature, the control device 40 obtains a required heating capacity for the battery 6 (for example, the amount of refrigerant injected from the battery refrigerant expansion valve V4b).

[0043] Next, in step S5, the control device 40 determines whether or not there is a temperature control request for the battery 6 in step S4. If a temperature control request for the battery 6 is obtained as a result (step S5: YES), that is, if a required value for the cooling capacity or heating capacity for the battery 6 was obtained in step S4, the process proceeds to step S6, where the control device 40 determines the air conditioning / battery coordinated control pattern. In this embodiment, the air conditioning / battery coordinated control pattern represents the control pattern of the temperature control system 100 according to the combination of the cooling / heating request for the air conditioner 5 and the temperature control request for the battery 6. For example, a table of air conditioning / battery coordinated control patterns, as shown in Figure 5, is pre-stored in memory 40b. The contents of each of the control patterns 1-a, 2-a, 2-b, 3-a, 3-b, 4-a, and 4-b shown in the table in Figure 5 will be described later. The control device 40 obtains the air conditioning / battery coordinated control pattern from memory 40b that corresponds to the cooling / heating request for the air conditioner 5 obtained in step S2 and the temperature control request for the battery 6 obtained in step S4.

[0044] After determining the air conditioning / battery coordinated control pattern in step S6, or if it is determined in step S5 that there is no temperature control request for battery 6 (i.e., neither cooling nor heating of battery 6 is requested) in step S4 (step S5: NO), in step S7, the control device 40 controls the refrigerant flowing through the temperature control system 100 based on the cooling / heating request for air conditioner 5 obtained in step S2, the cooling request for motor 4 obtained in step S3, the temperature control request for battery 6 obtained in step S4, and, if there is a temperature control request for battery 6, the air conditioning / battery coordinated control pattern determined in step S6 (step S7). Specifically, the operation of the high-pressure compressor 1a, low-pressure compressor 1b, cooling expansion valve V1a, heating valve V1b, refrigerant path switching valves V2, V3, and battery refrigerant expansion valves V4a, V4b is controlled to correspond to the required cooling or heating capacity of the air conditioner 5, the required cooling capacity for the motor 4, the required cooling or heating capacity for the battery 6, and the air conditioning / battery coordinated control pattern. After step S7, the control device 40 terminates control.

[0045] Next, referring to Figures 6 to 12, the contents of each of the control patterns 1-a, 2-a, 2-b, 3-a, 3-b, 4-a, and 4-b shown in the table in Figure 5 will be explained. The upper part of Figures 6 to 12 shows the PH diagram and PT diagram of the cooling or heating cycle of the air conditioner 5 and battery 6 in each control pattern, and the lower part shows the thermal cycle circuit of the temperature control system 100 in each control pattern. In the thermal cycle circuits of Figures 6 to 12, solid lines indicate refrigerant passages through which the refrigerant flows, and dashed lines indicate refrigerant passages through which the refrigerant does not flow.

[0046] [Air conditioning / battery coordinated control pattern 1-a] Figure 6 is an explanatory diagram showing the PH diagram, PT diagram, and refrigerant flow of the cooling cycle of motor 4, air conditioner 5, and battery 6 in air conditioning / battery coordinated control pattern 1-a. As shown in Figure 5, air conditioning / battery coordinated control pattern 1-a is an example of a control pattern when there is a cooling request for air conditioner 5 and a cooling request for battery 6.

[0047] In the air conditioning / battery coordinated control pattern 1-a, as shown in Figure 6, the temperature control system 100 includes a thermal cycle circuit for cooling the motor 4, a thermal cycle circuit for cooling by the air conditioner 5, and a thermal cycle circuit for cooling the battery 6 using the refrigerant after cooling the motor 4.

[0048] In the thermal cycle circuit that cools the motor 4, the refrigerant is compressed by the high-pressure compressor 1a to become high temperature and high pressure (approximately 120°C and 11 MPa in the example of Figure 6, point A2 in the PH and PT diagrams), cooled through the heat exchanger 2 via the refrigerant passage 11 (approximately 30°C in the example of Figure 6, point A3 in the PH and PT diagrams), and further expanded isenthalpically by the cooling expansion valve V1a to become low temperature (approximately 15°C and 5 MPa in the example of Figure 6, point A4 in the PH and PT diagrams), and supplied to the motor 4 from the refrigerant passage 12 (motor cooling path). The refrigerant supplied to the motor 4 cools the motor 4 by absorbing heat as it passes through the stator, rotor, bearings, etc. of the motor 4, and returns to the high-pressure compressor 1a via the refrigerant passage 14, reservoir tank 7, and refrigerant passage 18 (recovery path), where it is compressed again.

[0049] Furthermore, in the thermal cycle circuit that provides cooling by the air conditioner 5, the refrigerant is compressed by the high-pressure compressor 1a to become high temperature and high pressure (approximately 120°C and 11 MPa in the example of Figure 6, point A2 in the PH and PT diagrams), cooled through the heat exchanger 2 via the refrigerant passage 11 (approximately 30°C in the example of Figure 6, point A3 in the PH and PT diagrams), and then expands isenthalpically by the cooling expansion valve V1a to become low temperature (approximately 15°C and 5 MPa in the example of Figure 6, point A4 in the PH and PT diagrams), and is supplied to the air conditioner 5 from the refrigerant passage 13b (air conditioning cooling path). The refrigerant supplied to the air conditioner 5 cools the air flowing into the passenger compartment by absorbing heat as it passes through the passenger compartment heat exchanger of the air conditioner 5, and returns to the high-pressure compressor 1a via the refrigerant passage 15, reservoir tank 7 and refrigerant passage 18 (recovery path) (approximately 30°C and 5 MPa in the example of Figure 6, point A1 in the PH and PT diagrams), where it is compressed again.

[0050] Furthermore, in the thermal cycle circuit that cools the battery 6, the refrigerant used to cool the motor 4 (approximately 30°C and 5MPa in the example of Figure 6, point A1 in the PH and PT diagrams) is supplied to the battery refrigerant expansion valve V4a via the refrigerant passage 14 and the refrigerant path switching valve V2 (battery cooling path) (approximately 30°C and 5MPa in the example of Figure 6, point B1 in the PH and PT diagrams), and is injected into the battery case 6a by the battery refrigerant expansion valve V4a. At this time, the refrigerant expands and becomes colder than cell 6b (approximately 0°C and 0.1MPa in the example of Figure 6, point B2 in the PH and PT diagrams), and the refrigerant injected into the battery case 6a cools cell 6b by absorbing heat as it flows around cell 6b, and exits to the outside of the battery case 6a through the refrigerant passage 16 (approximately 20°C and 0.1MPa in the example of Figure 6, point B3 in the PH and PT diagrams). Subsequently, the refrigerant is compressed by the low-pressure compressor 1b (approximately 30°C and 5 MPa in the example in Figure 6, point B1 in the PH and PT diagrams), returns to the high-pressure compressor 1a through the refrigerant path switching valve V3, refrigerant passage 17, reservoir tank 7, and refrigerant passage 18 (recovery path), and is compressed again (approximately 120°C and 11 MPa in the example in Figure 6, point A2 in the PH and PT diagrams).

[0051] [Air conditioning / battery coordinated control pattern 2-a] Figure 7 is an explanatory diagram showing the PH diagram, PT diagram, and refrigerant flow for the cooling cycle of motor 4, the heating cycle of air conditioner 5, and the cooling cycle of battery 6 in the air conditioning / battery coordinated control pattern 2-a. As shown in Figure 5, air conditioning / battery coordinated control pattern 2-a is an example of a control pattern when there is a heating request for air conditioner 5 and a cooling request for battery 6.

[0052] In the air conditioning / battery coordinated control pattern 2-a, as shown in Figure 7, the temperature control system 100 includes a thermal cycle circuit for cooling the motor 4, a thermal cycle circuit for heating by the air conditioner 5, and a thermal cycle circuit for cooling the battery 6 using the refrigerant after cooling the motor 4. Of these, the thermal cycle circuit for cooling the motor 4 and the thermal cycle circuit for cooling the battery 6 are the same as in the air conditioning / battery coordinated control pattern 1-a.

[0053] Furthermore, in the thermal cycle circuit that provides heating by the air conditioner 5, the refrigerant is compressed by the high-pressure compressor 1a to become high temperature and high pressure (approximately 120°C and 11 MPa in the example of Figure 7, point A2 in the PH and PT diagrams), and expands by the temperature rise valve V1b, but the refrigerant, which is hotter than the air in the passenger compartment (approximately 75°C and 7 MPa in the example of Figure 7, point C1 in the PH and PT diagrams), is supplied to the air conditioner 5 from the refrigerant passage 13a (air conditioning heating path). The refrigerant supplied to the air conditioner 5 heats the air flowing into the passenger compartment by releasing heat as it passes through the passenger compartment heat exchanger of the air conditioner 5, and returns to the high-pressure compressor 1a through the refrigerant passage 15, reservoir tank 7 and refrigerant passage 18 (recovery path) (approximately 60°C and 7 MPa in the example of Figure 7, point C2 in the PH and PT diagrams), where it is compressed again.

[0054] [Air conditioning / battery coordinated control pattern 2-b] Figure 8 is an explanatory diagram showing the PH and PT diagrams and refrigerant flow for the cooling cycle of motor 4, and the heating cycles of air conditioner 5 and battery 6 in the air conditioning / battery coordinated control pattern 2-b. As shown in Figure 5, air conditioning / battery coordinated control pattern 2-b is an example of a control pattern when there is a heating request for air conditioner 5 and a heating request for battery 6.

[0055] In the air conditioning / battery coordinated control pattern 2-b, as shown in Figure 8, the temperature control system 100 includes a thermal cycle circuit for cooling the motor 4, a thermal cycle circuit for heating with the air conditioner 5, and a thermal cycle circuit for heating the battery 6 independently of the motor 4. Of these, the thermal cycle circuit for cooling the motor 4 is the same as in the air conditioning / battery coordinated control pattern 1-a, and the thermal cycle circuit for heating with the air conditioner 5 is the same as in the air conditioning / battery coordinated control pattern 2-a.

[0056] Furthermore, in the thermal cycle circuit that heats the battery 6, the refrigerant is compressed by the low-pressure compressor 1b to a high temperature (approximately 100°C and 0.3 MPa in the example of Figure 8, point B2 in the PH and PT diagrams), supplied to the refrigerant path switching valve V3 (battery heating path) and the battery refrigerant expansion valve V4b, and injected into the inside of the battery case 6a by the battery refrigerant expansion valve V4b. At this time, the refrigerant expands to a temperature higher than that of the cells 6b (approximately 80°C and 0.1 MPa in the example of Figure 8, point B3 in the PH and PT diagrams), and the refrigerant injected into the inside of the battery case 6a heats the cells 6b by dissipating heat as it flows around them, returns to the low-pressure compressor 1b through the refrigerant passage 16 (approximately 20°C and 0.1 MPa in the example of Figure 8, point B1 in the PH and PT diagrams), and is compressed again.

[0057] [Air conditioning / battery coordinated control pattern 3a] Figure 9 is an explanatory diagram showing the PH diagram and PT diagram of the cooling cycle of motor 4 and battery 6, and the flow of refrigerant in the air conditioning / battery coordinated control pattern 3-a. As shown in Figure 5, air conditioning / battery coordinated control pattern 3-a is an example of a control pattern when there is no request for heating or cooling from the air conditioner 5 (i.e., the air conditioner 5 is OFF) and there is a cooling request for the battery 6.

[0058] In the air conditioning / battery coordinated control pattern 3-a, as shown in Figure 9, the temperature control system 100 forms a thermal cycle circuit for cooling the motor 4 and a thermal cycle circuit for cooling the battery 6 using the refrigerant after cooling the motor 4. The thermal cycle circuit for cooling the motor 4 and the thermal cycle circuit for cooling the battery 6 are the same as in the air conditioning / battery coordinated control pattern 1-a.

[0059] [Air conditioning and battery coordinated control pattern 3-b] Figure 10 is an explanatory diagram showing the PH diagram and PT diagram and refrigerant flow for the cooling cycle of motor 4 and the heating cycle of battery 6 in the air conditioning / battery coordinated control pattern 3-b. As shown in Figure 5, air conditioning / battery coordinated control pattern 3-b is an example of a control pattern when there is no request for cooling or heating from the air conditioner 5 (i.e., the air conditioner 5 is OFF) and there is a request for heating from the battery 6.

[0060] In the air conditioning / battery coordinated control pattern 3-b, as shown in Figure 10, the temperature control system 100 is configured with a thermal cycle circuit for cooling the motor 4 and a thermal cycle circuit for heating the battery 6 independently of the motor 4. Of these, the thermal cycle circuit for cooling the motor 4 is the same as in the air conditioning / battery coordinated control pattern 1-a, and the thermal cycle circuit for heating the battery 6 is the same as in the air conditioning / battery coordinated control pattern 2-b.

[0061] [Air conditioning / battery coordinated control pattern 4-a] Figure 11 is an explanatory diagram showing the PH diagram, PT diagram, and refrigerant flow for the cooling cycle of the motor 4, the heating / cooling cycle of the air conditioner 5, and the cooling cycle of the battery 6 in the air conditioning / battery coordinated control pattern 4-a. As shown in Figure 5, the air conditioning / battery coordinated control pattern 4-a is an example of a control pattern when there is a dry heating request for the air conditioner 5 and a cooling request for the battery 6. In this embodiment, dry heating refers to operation in which cooling and heating are operated simultaneously in order to heat the air in the vehicle interior while dehumidifying it.

[0062] In the air conditioning / battery coordinated control pattern 4-a, as shown in Figure 11, the temperature control system 100 includes a thermal cycle circuit for cooling the motor 4, a thermal cycle circuit for performing dry heating by the air conditioner 5, and a thermal cycle circuit for cooling the battery 6 using the refrigerant after cooling the motor 4. Of these, the thermal cycle circuit for cooling the motor 4 is the same as in the air conditioning / battery coordinated control pattern 1-a, and the thermal cycle circuit for cooling the battery 6 is the same as in the air conditioning / battery coordinated control pattern 2-a.

[0063] Furthermore, in the thermal cycle circuit that performs dry heating by the air conditioner 5, the refrigerant is compressed by the high-pressure compressor 1a to become high temperature and high pressure (approximately 120°C and 11 MPa in the example in Figure 11, point A2 in the PH and PT diagrams). A portion of the high temperature and high pressure refrigerant is cooled by passing through the heat exchanger 2 via the refrigerant passage 11 (approximately 30°C in the example in Figure 11, point A3 in the PH and PT diagrams), and then expands isenthalpically by the cooling expansion valve V1a to become low temperature (approximately 15°C and 5 MPa in the example in Figure 11, point A4 in the PH and PT diagrams), and is supplied to the air conditioner 5 from the refrigerant passage 13b (air conditioning cooling path). The refrigerant supplied to the air conditioner 5 absorbs heat as it passes through the dehumidifying heat exchanger of the air conditioner 5, thereby dehumidifying the air flowing into the passenger compartment. It then returns to the high-pressure compressor 1a through the refrigerant passage 15, reservoir tank 7, and refrigerant passage 18 (recovery path) (approximately 30°C and 5 MPa in the example in Figure 11, point A1 in the PH and PT diagrams). In addition, any portion of the refrigerant that is not used for dehumidification at high temperature and high pressure is expanded by the heating valve V1b (approximately 75°C and 7 MPa in the example in Figure 11, point C1 in the PH and PT diagrams), and supplied to the air conditioner 5 from the refrigerant passage 13a (air conditioning heating path). The refrigerant supplied to the air conditioner 5 heats the air flowing into the passenger compartment by releasing heat as it passes through the passenger compartment heat exchanger of the air conditioner 5. It then returns to the high-pressure compressor 1a through the refrigerant passage 15, reservoir tank 7, and refrigerant passage 18 (recovery path) (approximately 60°C and 7MPa in the example in Figure 11, point C2 in the PH and PT diagrams), where it is compressed again along with the refrigerant used for dehumidification.

[0064] [Air conditioning / battery coordinated control pattern 4-b] Figure 12 is an explanatory diagram showing the PH and PT diagrams and refrigerant flow for the cooling cycle of motor 4, the heating / cooling cycle of air conditioner 5, and the heating cycle of battery 6 in the air conditioning / battery coordinated control pattern 4-b. As shown in Figure 5, air conditioning / battery coordinated control pattern 4-b is an example of a control pattern when there is a dry heating request for air conditioner 5 and a heating request for battery 6.

[0065] In the air conditioning / battery coordinated control pattern 4-b, as shown in Figure 12, the temperature control system 100 includes a thermal cycle circuit for cooling the motor 4, a thermal cycle circuit for dry heating by the air conditioner 5, and a thermal cycle circuit for heating the battery 6 independently of the motor 4. Of these, the thermal cycle circuit for cooling the motor 4 is the same as in the air conditioning / battery coordinated control pattern 1-a, the thermal cycle circuit for dry heating by the air conditioner 5 is the same as in the air conditioning / battery coordinated control pattern 4-a, and the thermal cycle circuit for heating the battery 6 is the same as in the air conditioning / battery coordinated control pattern 2-b.

[0066] [Mechanism of Action and Effects] Next, the effects and benefits of the electric vehicle temperature control system of this embodiment described above will be explained.

[0067] According to the temperature control system 100 of this embodiment, the cooling of the air conditioner 5, the motor 4, and the battery 6 are performed using a common refrigerant containing CO2, so the overall configuration of the temperature control system 100 can be made compact. Furthermore, when cooling the motor 4 and the battery 6, the refrigerant used to cool the motor 4 is supplied to the battery refrigerant expansion valve V4a, and is further expanded and injected into the battery case 6a from the battery refrigerant expansion valve V4a. This allows the cells 6b of the battery 6 to be directly cooled by the refrigerant while maintaining the same level of strength as conventional systems for the cell 6b and the structure of the battery case 6a. As a result, the temperature of the battery 6 can be controlled with high responsiveness without increasing the weight of the battery 6 or raising manufacturing costs. In addition, there is no need to provide a separate heat exchanger solely for cooling the battery 6, so the overall weight and efficiency of the temperature control system 100 can be reduced, making it a system that can be applied to lightweight sports cars to provide excellent handling and acceleration, enhancing the joy of driving.

[0068] Furthermore, since the refrigerant compressed by the low-pressure compressor 1b after passing through the battery 6, the refrigerant that has passed through the air conditioner 5, and the refrigerant that has passed through the motor 4 can all be compressed by the high-pressure compressor 1a, a common high-pressure compressor 1a can be used to compress the refrigerant used for cooling the air conditioner 5, motor 4, and battery 6, making the overall configuration of the temperature control system 100 more compact.

[0069] Furthermore, by expanding the high-temperature refrigerant compressed by the low-pressure compressor 1b and injecting it into the battery case 6a through the battery refrigerant expansion valve V4b, the cells 6b can be directly heated by the refrigerant. This allows for highly responsive temperature control of the battery 6 without increasing the weight of the battery 6 or raising manufacturing costs.

[0070] Furthermore, since the necessary amount of refrigerant corresponding to the heat generation and temperature of the battery 6 can be precisely injected into the battery case 6a from injectors constituting the battery refrigerant expansion valves V4a and V4b at appropriate pressure, temperature fluctuations of the battery cells 6b can be suppressed, thereby reducing the degradation of the battery 6 due to thermal cycling.

[0071] Furthermore, the air conditioner 5 can be heated by supplying the high-temperature, high-pressure refrigerant compressed by the high-pressure compressor 1a to the air conditioner 5 via the refrigerant passage 13a. [Explanation of Symbols]

[0072] 1a High-pressure compressor 1b Low-pressure compressor 2 Heat exchanger 4 motors 4a Motor internal structure 5. Air conditioner 6 batteries 6a Battery Case 6b cell 7. Reservoir Tank 11-18 Refrigerant passage 31 Refrigerant temperature sensor 32 Refrigerant pressure sensor 33 Battery temperature sensor 34 Motor temperature sensor 35. Indoor / Outdoor Air Temperature Sensor 36. Air conditioning switch 40 Control device 100 Temperature Control System 200 electric vehicles V1a Cooling Expansion Valve V1b Temperature rise valve V2 Cooling Path Switching Valve V3 Cooling Path Switching Valve V4a, V4b Battery Refrigerant Expansion Valve

Claims

1. A temperature control system for an electric vehicle comprising an air conditioning unit for performing air conditioning, a motor for driving, and a battery with cells housed inside a battery case, CO 2 A compressor that compresses a refrigerant containing, A heat exchanger for cooling the refrigerant compressed by the compressor, A first expansion valve for expanding the refrigerant cooled by the heat exchanger, During the cooling of the air conditioning unit, an air conditioning cooling path supplies the refrigerant expanded by the first expansion valve to the air conditioning unit, During the cooling of the motor, a motor cooling path supplies the refrigerant expanded by the first expansion valve to the motor, A second expansion valve that expands the refrigerant and injects it into the inside of the battery case, A battery cooling path supplies the refrigerant used to cool the motor to the second expansion valve when the motor is being cooled and the battery is being cooled, A recovery path that supplies the refrigerant that has passed through the air conditioning unit, the refrigerant that has passed through the motor, and the refrigerant that has passed through the battery to the compressor, A temperature control system for electric vehicles equipped with the following features.

2. The aforementioned compressor is A first compressor compresses the refrigerant that has passed through the battery, It includes a second compressor that compresses the refrigerant that has passed through the air conditioning unit and the refrigerant that has passed through the motor, The electric vehicle temperature control system according to claim 1, wherein the second compressor further compresses the refrigerant compressed by the first compressor when the motor and the battery are being cooled.

3. The electric vehicle temperature control system according to claim 2, further comprising a battery heating path that supplies the refrigerant compressed by the first compressor to the second expansion valve when the battery is heated.

4. The electric vehicle temperature control system according to any one of claims 1 to 3, wherein the second expansion valve comprises a common rail for storing the refrigerant and an injector for injecting the refrigerant stored in the common rail into the inside of the battery case.

5. A temperature control system for an electric vehicle according to any one of claims 1 to 3, comprising an air conditioning heating path that supplies the refrigerant compressed by the compressor to the air conditioning unit when the air conditioning unit is being heated.

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