Vehicle thermal management device

Abstract

To provide a vehicle thermal management device capable of appropriately cooling a battery to suppress progress of degradation and avoiding occurrence of condensation, while suppressing an increase in cost.SOLUTION: A vehicle thermal management device 1 includes: a refrigerant circuit 3; a first heat medium circuit 6 in which a heat medium that is cooled by a refrigerant flowing through the refrigerant circuit 3 and exchanges heat with a temperature control target other than a battery 4 is circulated; and a second heat medium circuit 7 in which a heat medium that is cooled by the heat medium flowing through the first heat medium circuit 6 and exchanges heat with the battery 4 is circulated. The heat medium is circulated through the second heat medium circuit 7 so that a temperature difference within the battery 4 does not become equal to or greater than a predetermined value, or a temperature of the battery 4 does not become equal to or greater than a predetermined threshold.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a thermal management device for a vehicle that uses a refrigerant circuit and a heat medium circuit to cool a battery, etc. [Background technology]

[0002] Conventionally, batteries mounted on electric vehicles (electric cars, hybrid cars, etc.) generate heat. For this reason, a system has been developed in which a heat medium such as water is cooled by a refrigerant in a refrigerant circuit for air conditioning the vehicle interior, and this heat medium also cools the battery (see, for example, Patent Document 1). However, batteries cannot operate efficiently at either low or high temperatures, and the optimum temperature range is approximately +10°C to +30°C.

[0003] In addition, a system has been developed in which a heat medium is cooled by a refrigerant in a refrigerant circuit, and this heat medium is used to air condition the vehicle interior and cool the battery.In such systems, the heat medium is cooled in a refrigerant-heat medium heat exchanger that exchanges heat with a heat absorber in the refrigerant circuit, and then circulated to an indoor heat exchanger for air conditioning and the battery.However, since the heat medium is cooled according to a target temperature of the indoor heat exchanger, the temperature of the heat medium may become lower than the dew point temperature of the outside air.If this heat medium is subjected to heat exchange with the battery to cool the battery, condensation may occur inside the battery pack, which may cause problems such as a short circuit.

[0004] Therefore, systems have been developed that provide separate heat absorbers in the refrigerant circuit for cabin air conditioning and battery cooling, as well as systems that provide separate refrigerant circuits and heat medium circuits for cabin air conditioning and battery cooling (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 7388385 [Patent Document 2] Japanese Patent Application Publication No. 2023-168209 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in such conventional systems, the number of components such as expansion valves and the like increases in addition to the heat exchangers, and the volume of the refrigerant circuit and heat medium circuit also increases, which causes a problem of rising costs, especially when a heat medium with high insulation properties (such as a fluorine-based inert liquid) is used in consideration of battery safety.

[0007] The present invention has been made to solve the above-mentioned conventional technical problems, and provides a thermal management device for a vehicle that can appropriately cool the battery, suppress the progression of deterioration, and avoid the occurrence of condensation while suppressing cost increases. [Means for solving the problem]

[0008] In order to solve the above problems, the vehicle thermal management device of the present invention comprises a refrigerant circuit, a first heat medium circuit in which a heat medium that is cooled by the refrigerant flowing through the refrigerant circuit and exchanges heat with a temperature control target other than a battery is circulated, and a second heat medium circuit in which a heat medium that is cooled by the heat medium flowing through the first heat medium circuit and exchanges heat with the battery is circulated, characterized in that the heat medium is circulated in the second heat medium circuit so that the temperature difference within the battery does not exceed a predetermined value or the temperature of the battery does not exceed a predetermined threshold.

[0009] The vehicle thermal management device of the invention of claim 2 is characterized in that in the above invention, the refrigerant circuit has a compressor that compresses refrigerant, a radiator that radiates heat from the high-temperature refrigerant discharged from the compressor, a pressure reduction device that depressurizes the refrigerant that has radiated heat in the radiator, and a heat absorber that absorbs heat from the refrigerant that has been depressurized in the pressure reduction device, the first heat medium circuit has a refrigerant-heat medium heat exchanger that exchanges heat with the heat absorber, a heat exchanger for a temperature control target, and a heat medium-heat medium heat exchanger, and the second heat medium circuit has a heat radiating section that exchanges heat with the heat medium-heat medium heat exchanger.

[0010] The vehicle thermal management device of the invention of claim 3 is characterized in that in the above invention, the heat exchanger for the temperature control object provided in the first heat medium circuit is an interior heat exchanger for air conditioning the vehicle interior, and the vehicle interior is air-conditioned using a heat medium cooled by a refrigerant in the refrigerant-heat medium heat exchanger.

[0011] The vehicle thermal management device of the invention of claim 4 is the invention of claim 2 or claim 3, characterized in that the first heat medium circuit has a first pump that circulates the heat medium within the first heat medium circuit and a valve device that distributes the heat medium that has passed through the refrigerant-heat medium heat exchanger to a heat exchanger for a temperature control target and a heat medium-heat medium heat exchanger, and the second heat medium circuit has a second pump that circulates the heat medium within the second heat medium circuit, and is equipped with a control device that controls the circulation of the heat medium in each heat medium circuit by each pump and valve device.

[0012] The vehicle thermal management device of the invention of claim 5 is characterized in that it comprises a control device for controlling the circulation of the heat medium in each heat medium circuit in the invention of claim 1, and this control device has a start-up control unit that increases the amount of heat medium circulating in the second heat medium circuit when cooling of the battery starts compared to steady state.

[0013] The vehicle thermal management device of the invention of claim 6 is characterized in that in the above invention, the control device has a battery cooling control unit that controls the circulation of the heat medium in each heat medium circuit based on a predetermined target battery temperature, and a target battery temperature correction unit that corrects the target battery temperature so that it is higher than the dew point temperature of the outside air when the target battery temperature is lower than the dew point temperature of the outside air. [Effects of the Invention]

[0014] According to the present invention, a refrigerant circuit, a first heat medium circuit in which a heat medium that is cooled by the refrigerant flowing through the refrigerant circuit and exchanges heat with a temperature control target other than the battery is circulated, and a second heat medium circuit in which a heat medium that is cooled by the heat medium flowing through the first heat medium circuit and exchanges heat with the battery is circulated, making it possible to reduce the number of heat exchangers such as heat absorbers in the refrigerant circuit and the volume of the circuit, and simplify the configuration as in the invention of claim 2. Furthermore, because the second heat medium circuit for cooling the battery and the first heat medium circuit for cooling a temperature control target other than the battery are independent, for example, even when a heat medium with high insulation is used in the second heat medium circuit, the amount of heat medium can be reduced, making it possible to suppress an increase in costs overall.

[0015] Furthermore, since the first heat medium circuit and the second heat medium circuit are independent, it is easier to manage the temperature of the battery, and it is also possible to avoid the inconvenience of the battery being cooled excessively and condensation occurring due to the need to cool temperature control targets other than the battery.

[0016] In particular, the heat medium is circulated in the second heat medium circuit so that the temperature difference within the battery does not exceed a predetermined value or the temperature of the battery does not exceed a predetermined threshold, thereby making it possible to effectively suppress the deviation in the degree of deterioration caused by the temperature difference within the battery and the progression of deterioration of the entire battery.

[0017] Specifically, as in the invention of claim 2, the refrigerant circuit has a compressor that compresses the refrigerant, a radiator that radiates heat from the high-temperature refrigerant discharged from the compressor, a pressure reducing device that depressurizes the refrigerant that has radiated heat in the radiator, and a heat absorber that absorbs heat from the refrigerant that has been depressurized in the pressure reducing device, and the first heat medium circuit has a refrigerant-heat medium heat exchanger that exchanges heat with the heat absorber, a heat exchanger for the temperature control target, and a heat medium-heat medium heat exchanger, and the second heat medium circuit has a heat radiating part that exchanges heat with the heat medium-heat medium heat exchanger.

[0018] As in the invention of claim 3, the first heat medium circuit has an interior heat exchanger for vehicle interior air conditioning as the heat exchanger for the temperature control target, and the vehicle interior is air-conditioned using the heat medium cooled by the refrigerant in the refrigerant-heat medium heat exchanger. This makes it possible to appropriately perform both vehicle interior air conditioning and battery cooling while simplifying the structure and reducing costs.

[0019] Furthermore, as in the invention of claim 4, the first heat medium circuit is provided with a first pump that circulates the heat medium within the first heat medium circuit, and a valve device that distributes the heat medium that has passed through the refrigerant-heat medium heat exchanger to the heat exchanger for the temperature control object and the heat medium-heat medium heat exchanger, and the second heat medium circuit is provided with a second pump that circulates the heat medium within the second heat medium circuit, and a control device is used to control the circulation of the heat medium in each heat medium circuit by each pump and valve device, thereby making it possible to more appropriately cool the battery and the temperature control object other than the battery.

[0020] However, since the heat medium in the second heat medium circuit is cooled by the heat absorber of the refrigerant circuit via the heat medium in the first heat medium circuit, there is a concern that the responsiveness of the battery cooling may deteriorate. Therefore, as in claim 5, by providing a start-up control unit in the control device that controls the circulation of the heat medium in each heat medium circuit, the start-up performance of the battery cooling can be ensured by increasing the amount of heat medium circulating in the second heat medium circuit at the start of battery cooling compared to steady state.

[0021] Furthermore, as in the invention of claim 6, the control device is provided with a battery cooling control unit that controls the circulation of the heat medium in each heat medium circuit based on a predetermined target battery temperature, and a target battery temperature correction unit that corrects the target battery temperature to be higher than the dew point temperature of the outside air when the target battery temperature is below the dew point temperature, thereby making it possible to effectively prevent condensation from forming on the battery and improve the stability and safety of the device. [Brief explanation of the drawings]

[0022] [Figure 1]1 is a diagram showing a heat medium circuit and a refrigerant circuit of an embodiment of a vehicle thermal management device of the present invention; [Figure 2] 2 is a block diagram illustrating the configuration of an embodiment of the vehicle thermal management device of FIG. 1. FIG. [Figure 3] 3 is a functional block diagram relating to battery cooling control of the control device of FIG. 2. FIG. [Figure 4] 4 is another diagram of a heat medium circuit and a refrigerant circuit of the vehicle thermal management device of FIG. 1 (cooling mode). FIG. [Figure 5] 1. FIG. 4 is yet another diagram of a heat medium circuit and a refrigerant circuit of the vehicle thermal management device of FIG. 1 (battery cooling mode). [Figure 6] 1. FIG. 4 is yet another diagram of a heat medium circuit and a refrigerant circuit of the vehicle thermal management device of FIG. 1 (air conditioning+battery cooling mode). [Figure 7] FIG. 10 is a diagram illustrating temperature transitions of various parts in an air-conditioning+battery cooling mode. [Figure 8] 4 is a flowchart illustrating battery cooling control by the control device of FIG. 3. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. (1) Configuration of the Vehicle Thermal Management Device 1 Fig. 1 shows the configuration of a heat medium circuit 2 and a refrigerant circuit 3 of a vehicle thermal management device 1 according to one embodiment of the present invention, and Fig. 2 and Fig. 3 show examples of functional blocks of the vehicle thermal management device 1 shown in Fig. 1. The vehicle thermal management device 1 according to the embodiment conditions the interior of an electric vehicle (EV) such as an electric vehicle or a hybrid vehicle, and also regulates the temperature of a battery 4 mounted on the electric vehicle (EV), and is configured to include a first heat medium circuit 6 and a second heat medium circuit 7 that are independent components of the heat medium circuit 2, a refrigerant circuit 3, and a control device 9.

[0024] Therefore, in this embodiment, the battery 4 and the interior of the electric vehicle EV are temperature controlled, and of these, the interior of the electric vehicle EV is an embodiment in which the temperature is controlled other than the battery 4. Note that, in addition to the interior of the vehicle, other temperature controlled objects besides the battery 4 may also include the traction motor (Motor) 8 of the electric vehicle EV, an inverter (not shown) that drives the traction motor, and a power control unit 10 (PCU in FIG. 2) of the electric vehicle EV. The battery 4 is composed of multiple battery cells. Furthermore, in this application, the concept of battery 4 also includes a fuel cell.

[0025] (1-1) Configuration of Heat Transfer Medium Circuit 2 First, the heat medium circuit 2 of the vehicle thermal management device 1 of the embodiment will be described with reference to Fig. 1. In the case of the present invention, the heat medium circuit 2 is composed of an independent first heat medium circuit 6 and a second heat medium circuit 7.

[0026] (1-1-1) Configuration of the first heat medium circuit 6 Of these, the first heat medium circuit 6 is composed of pumps 11 and 12 (both of which are first pumps in the present invention), a heating section 16 (heat exchanger), a cooling section 17 as a refrigerant-heat medium heat exchanger in the present invention, an indoor heat exchanger 18 as a heat exchanger for a temperature control target in the present invention, another indoor heat exchanger 19, an outdoor heat exchanger (radiator) 22, an integrated valve 23, a three-way valve 24 and a four-way valve 26 as valve devices in the present invention, a heat medium-heat medium heat exchanger 27, etc., and these are connected to the driving motor 8 and an electric heater (ECH) 33 as an auxiliary heating device by heat medium piping 34 as shown in FIG. 1.

[0027] In this case, a jacket structure is configured around the traction motor 8, and a heat medium (water in this embodiment) flows through this jacket, so that the traction motor 8 exchanges heat with the heat medium. In addition, the exterior heat exchanger 22 is disposed outside the passenger compartment of the electric vehicle EV, and an exterior blower 36 ventilates the outside air.

[0028] Furthermore, the interior heat exchangers 18 and 19 are disposed in an air flow passage 39 of an HVAC unit 38 that supplies air for air conditioning to the interior of the electric vehicle EV. Inside air and outside air are ventilated through this air flow passage 39 by an interior blower 41, and the inside air and outside air are switched between by an intake switching damper 42. Furthermore, reference numeral 43 denotes an air mix damper that adjusts the ventilation ratio to the interior heat exchanger 19, which is disposed on the downwind side of the interior heat exchanger 18 in the air flow passage 39.

[0029] The four-way valve 26 has four ports A, B, C, and D, and an internal valve element is driven by a motor or a solenoid to switch between switching mode 1 and switching mode 2. In this case, in switching mode 1, the heat medium flowing in from port A flows to port C, and the heat medium flowing in from port B flows to port D. In switching mode 2, the heat medium flowing in from port A flows to port D, and the heat medium flowing in from port B flows to port C.

[0030] The integrated valve 23 has eight ports, B, C, D, E, F, I, J, and L, and an internal valve element is rotated by a motor (servo motor). Depending on the rotational position of the valve element, the integrated valve 23 can be switched to one of several switching modes, of which switching mode 1 is used in this embodiment. In this case, in switching mode 1, port C communicates with port B, port L communicates with port E, port J communicates with port F, and port D communicates with port I (FIG. 1).

[0031] Furthermore, the three-way valve 24 has one inlet port and two outlet ports, and distributes the heat medium flowing in from the inlet port to one outlet port and the other outlet port. The distribution amount can be adjusted within the range of 0 to 100% to one outlet port and 100% to 0 to the other outlet port.

[0032] The outlet of the cooling section 17 is connected to the inlet port of the three-way valve 24, one outlet port of the three-way valve 24 is connected to the inlet of the indoor heat exchanger 18, the outlet of the indoor heat exchanger 18 is connected to the suction side of the pump 11, and the discharge side of the pump 11 is connected to the inlet of the cooling section 17, all of which are connected by heat medium piping 34.

[0033] The other outlet port of the three-way valve 24 is connected to port F of the integrated valve 23, port J of the integrated valve 23 to the inlet of the electric heater 33, the outlet of the electric heater 33 to the inlet of the heat medium-heat medium heat exchanger 27, the outlet of the heat medium-heat medium heat exchanger 27 to port C of the integrated valve 23, and port B of the integrated valve 23 to the suction side of the pump 11, all of which are connected by heat medium piping 34.

[0034] The outlet of heating section 16 is connected to the inlet of indoor heat exchanger 19, the outlet of indoor heat exchanger 19 is connected to port A of four-way valve 26, port C of four-way valve 26 is connected to the inlet of outdoor heat exchanger 22, the outlet of outdoor heat exchanger 22 is connected to port I of integrated valve 23, port D of integrated valve 23 is connected to the inlet of travel motor 8, the outlet of travel motor 8 is connected to port J of integrated valve 23, port E of integrated valve 23 is connected to port B of four-way valve 26, and port D of four-way valve 26 is connected to the suction side of pump 12, all of which are connected by heat medium piping 34.

[0035] (1-1-2) Configuration of the second heat medium circuit 7 On the other hand, the second heat medium circuit 7 is independent of the first heat medium circuit 6 and is composed of a pump 13 (second pump in the present invention) and a heat dissipation unit 25 (heat exchanger), and these are connected to the battery 4 by heat medium piping 35 as shown in FIG. 1.

[0036] In this case, a jacket structure is also formed around the battery 4, and the heat medium flows through this jacket, so that the battery 4 exchanges heat with the heat medium. In this embodiment, a heat medium with high insulation properties (for example, a fluorine-based inert liquid) is used as the heat medium circulating in the second heat medium circuit 7.

[0037] The discharge side of the pump 13 is connected to the inlet of the heat radiating section 25, the outlet of the heat radiating section 25 to the inlet of the battery 4, and the outlet of the battery 4 to the suction side of the pump 13, all of which are connected by heat medium piping 35. The heat radiating section 25 of the second heat medium circuit 7 is disposed in a heat exchange relationship with the heat medium-heat medium heat exchanger 27 of the first heat medium circuit 6, and heat is exchanged between the heat medium (heat medium such as water) flowing through the first heat medium circuit 6 and the heat medium (heat medium with high insulation properties) flowing through the second heat medium circuit 7.

[0038] (1-2) Configuration of refrigerant circuit 3 1 is a heat pump circuit in which a compressor 44 that compresses a refrigerant (a flammable refrigerant such as R290 in this embodiment), a radiator 46 that radiates heat from the refrigerant (high-temperature refrigerant) discharged from the compressor 44, an expansion valve 47 as a pressure reducing device that reduces the pressure of the refrigerant that has radiated heat in the radiator 46, a heat absorber 48 that evaporates and absorbs heat from the refrigerant that has been decompressed by the expansion valve 47, and an accumulator 49 are sequentially connected in a ring shape by refrigerant piping 52. The radiator 46 of the refrigerant circuit 3 and the heating section 16 of the first heat medium circuit 6 are arranged in a heat exchange relationship, and the heat absorber 48 and the cooling section 17 are arranged in a heat exchange relationship.

[0039] (1-3) Configuration of the control device 9 Next, the configuration of the control device 9 will be described with reference to Figures 2 and 3. The control device 9 is configured with a microcomputer equipped with a processor, memory, and input / output interface, and as shown in Figure 2, has as its functions an operation mode determination unit 51, a control target value calculation unit 52, an operation mode switching control unit 53, and a control target value control unit 54.

[0040] As shown in FIG. 1, the control device 9 of the embodiment receives detection data from an indoor heat exchanger inlet temperature sensor 62 that detects the temperature of the heat medium flowing into the indoor heat exchanger 18, a battery inlet temperature sensor 65 that detects the temperature of the heat medium flowing into the battery 4, and other sensors (representatively shown by reference numeral 56 in FIG. 2) that detect the outside air temperature and humidity, the temperature of the air inside the passenger compartment of the electric vehicle EV and the temperature of the air blown into the passenger compartment, the temperature and pressure of each part of the refrigerant circuit 3, the amount of solar radiation into the passenger compartment, etc.

[0041] In addition, the control device 9 is connected to the aforementioned integrated valve 234, three-way valve 24, four-way valve 26, and pumps 11 to 13 (representatively shown by reference numeral 57 in FIG. 2), as well as the aforementioned compressor 44, expansion valve 47, outdoor blower 36, indoor blower 39, suction switching damper 42, air mix damper 43, and electric heater (ECH) 33 (representatively shown by reference numeral 58 in FIG. 2), and these are controlled by the control device 9.

[0042] Furthermore, the control device 9 is configured to transmit and receive data (driving information such as temperature data) to and from a battery management system (BMS) 61 that controls the charging and discharging of the battery 4, and the above-mentioned power control unit (PCU) 10, via a CAN 59 of the electric vehicle EV. The temperature of each battery cell of the battery 4 is transmitted from the battery management system 61 to the control device 9. The control device 9 obtains necessary data (driving information such as vehicle speed) from a vehicle control unit (VCU) 60 of the electric vehicle EV via the CAN 59.

[0043] An operation mode determination unit 51 of the control device 9 determines the air conditioning of the vehicle cabin, such as cooling or heating, and each operation mode (described later) of the heat medium circuit 2 and the refrigerant circuit 3, based on the detection data of the above-mentioned sensor 56, etc. A control target value calculation unit 52 calculates a control target value for the operation mode determined by the operation mode determination unit 51. An operation mode switching control unit 53 controls the integrated valve 23, three-way valve 24, four-way valve 26, and pumps 11 to 13 of the heat medium circuit 2, based on the operation mode determined by the operation mode determination unit 51. A control target value control unit 54 controls the compressor 44, expansion valve 47, each of the fans 36 and 41, the electric heater (ECH) 33, and each of the dampers 42 and 43 of the refrigerant circuit 3, based on the control target value calculated by the control target value calculation unit 52.

[0044] 3 shows functional blocks related to the battery cooling control of the control device 9 of the embodiment. In FIG. 3, 63 is a battery cooling control unit, 64 is a start-up control unit, and 66 is a target battery temperature correction unit. Battery cooling control by these units will be described in detail later.

[0045] (2) Operation mode of the control device 9 Next, the operation modes of the control device 9 of the embodiment will be described with reference to Figures 4 to 6. The control device 9 has a plurality of operation modes such as a cooling mode, a battery cooling mode, a cooling + battery cooling mode, a heating mode, a dehumidifying heating mode, a waste heat utilization mode, etc., but here, the cooling mode, the battery cooling mode, and the cooling + battery cooling mode that are relevant to the present invention will be described.

[0046] (2-1) Cooling mode First, Figure 4 shows the cooling mode controlled by the control device 9. In this cooling mode, the compressor 44, outdoor blower 36, indoor blower 41, and pumps 11 to 13 are operated, the four-way valve 26 is set to switching mode 1, and the integrating valve 23 is also set to switching mode 1. In addition, the three-way valve 24 is set to a state in which the inlet port communicates with only one of the outlet ports. Furthermore, the air mix damper 43 is set to a state in which ventilation is not provided to the indoor heat exchanger 19.

[0047] As a result, the high-temperature refrigerant discharged from the compressor 44 of the refrigerant circuit 3 radiates heat in the radiator 46 to the heat medium flowing in the heating section 16, and in the heat absorber 48, the refrigerant decompressed in the expansion valve 47 evaporates and absorbs heat from the heat medium flowing in the cooling section 17. The refrigerant that has left the heat absorber 48 is separated into gas and liquid in the accumulator 49, and then is sucked into the compressor 44.

[0048] The heat medium discharged from the pump 12 of the first heat medium circuit 6 reaches the heating section 16, where it is heated by the refrigerant (the refrigerant releases heat). The heat medium heated in the heating section 16 flows into the indoor heat exchanger 19. The heat medium leaving this indoor heat exchanger 19 flows into port A of the four-way valve 26, flows out from port C, and flows into the outdoor heat exchanger 22.

[0049] The heat medium that leaves the outdoor heat exchanger 22 flows into port I of the integrated valve 23, flows out from port D, and flows into the travel motor 8. The heat medium that leaves the travel motor 8 flows into port L of the integrated valve 23, flows out from port E, and flows into port B of the four-way valve 26. The heat medium that flows into port B of the four-way valve 26 leaves from port D and repeats the cycle of returning to the pump 12 (as indicated by the arrows next to the heat medium piping 34 in FIG. 4).

[0050] The heat medium discharged from the pump 11 of the first heat medium circuit 6 reaches the cooling unit 17, where it is cooled by the refrigerant (the refrigerant absorbs heat). The heat medium cooled in the cooling unit 17 flows into the inlet port of the three-way valve 24, exits from one of the outlet ports, and flows into the indoor heat exchanger 18. The heat medium leaving the indoor heat exchanger 18 then repeats its circulation returning to the pump 11 (as indicated by the arrows next to the heat medium piping 34 in FIG. 4).

[0051] As a result, in the cooling mode, the heat medium absorbs heat in the indoor heat exchanger 18. Since the air blown into the vehicle compartment flows through the indoor heat exchanger 18, the air cooled by the indoor heat exchanger 18 is blown into the vehicle compartment, thereby cooling the vehicle compartment (the temperature control target).

[0052] On the other hand, the heat medium discharged from the pump 13 of the second heat medium circuit 7 flows into the heat dissipation section 65, and when the heat medium is circulated in the heat medium-heat medium heat exchanger 27, the heat medium in the second heat medium circuit 7 is cooled there by the heat medium in the first heat medium circuit 6. The heat medium discharged from the heat dissipation section 65 reaches the battery 4, exchanges heat with the battery 4, and then repeats the circulation of leaving the battery 4 and returning to the pump 13 (as indicated by the arrows next to the heat medium piping 35 in FIG. 4).

[0053] In this embodiment, the pump 13 of the second heat medium circuit 7 is always operated in any operation mode, and the heat medium is always circulated through the battery 4.

[0054] (2-2) Battery cooling mode First, Figure 5 shows the battery cooling mode operated by the control device 9. In this battery cooling mode, the compressor 44, the outdoor blower 36, the indoor blower 41, and the pumps 11 to 13 are also operated, the four-way valve 26 is set to switching mode 1, and the integrated valve 23 is also set to switching mode 1. In addition, the three-way valve 24 is set to a state in which only the inlet port communicates with the other outlet port. Furthermore, the air mix damper 43 is set to a state in which no air is circulated to the indoor heat exchanger 19.

[0055] As a result, the high-temperature refrigerant discharged from the compressor 44 of the refrigerant circuit 3 radiates heat in the radiator 46 to the heat medium flowing in the heating section 16, and in the heat absorber 48, the refrigerant decompressed in the expansion valve 47 evaporates and absorbs heat from the heat medium flowing in the cooling section 17. The refrigerant that has left the heat absorber 48 is separated into gas and liquid in the accumulator 49, and then is sucked into the compressor 44.

[0056] The heat medium discharged from the pump 12 of the first heat medium circuit 6 reaches the heating section 16, where it is heated by the refrigerant (the refrigerant releases heat). The heat medium heated in the heating section 16 flows into the indoor heat exchanger 19. The heat medium leaving this indoor heat exchanger 19 flows into port A of the four-way valve 26, flows out from port C, and flows into the outdoor heat exchanger 22.

[0057] The heat medium that leaves the outdoor heat exchanger 22 flows into port I of the integrated valve 23, flows out from port D, and flows into the travel motor 8. The heat medium that leaves the travel motor 8 flows into port L of the integrated valve 23, flows out from port E, and flows into port B of the four-way valve 26. The heat medium that flows into port B of the four-way valve 26 leaves from port D and repeats the cycle of returning to the pump 12 (as indicated by the arrows next to the heat medium piping 34 in FIG. 5).

[0058] The heat medium discharged from the pump 11 of the first heat medium circuit 6 reaches the cooling unit 17, where the heat medium is cooled by the refrigerant (the refrigerant absorbs heat). The heat medium cooled in the cooling unit 17 flows into the inlet port of the three-way valve 24, exits from the other outlet port, flows into port F of the integrating valve 23, exits from port J, passes through the electric heater 33 (not generating heat), and then flows into the heat medium-heat medium heat exchanger 27. The heat medium exiting the heat medium-heat medium heat exchanger 27 then flows into port C of the integrating valve 23, exits from port B, and repeats the cycle of returning to the pump 11 (as indicated by the arrows next to the heat medium piping 34 in FIG. 5).

[0059] On the other hand, the heat medium discharged from the pump 13 of the second heat medium circuit 7 flows into the heat radiator 65, where it is cooled by the heat medium of the first heat medium circuit 6 flowing through the heat medium-heat medium heat exchanger 27. The heat medium coming out of the radiator 65 reaches the battery 4, exchanges heat with the battery 4, and then leaves the battery 4 and returns to the pump 13, repeating this cycle (as indicated by the arrows next to the heat medium piping 35 in FIG. 5 ).

[0060] As a result, the battery 4 exchanges heat with the heat medium of the second heat medium circuit 7, which has been cooled by the heat medium of the first heat medium circuit 6, at the heat dissipation section 65, and is cooled by absorbing heat. In this battery cooling mode, the control device 9 determines the temperature Tb of the heat medium of the second heat medium circuit 7 flowing into the battery 4, detected by the battery inlet temperature sensor 65, as the temperature of the battery 4, and controls the rotation speed of the compressor 44 so that the temperature Tb does not exceed, for example, +25°C within the optimum temperature range of the battery 4 (+10°C to +30°C). In this way, the control device 9 prevents the temperature of the battery 4 from exceeding a predetermined threshold (the target battery temperature Tbset: +25°C). In the present invention, preventing the temperature of the battery 4 from exceeding the predetermined threshold (target battery temperature Tbset: +25°C) means that the temperature of the battery 4 is kept lower than the predetermined threshold (target battery temperature Tbset: +25°C). However, the control device 9 controls the compressor 44 so that the temperature Tb does not fall below the lower limit (+10°C) of the optimum temperature range.

[0061] In this case, the battery cooling control unit 63 of the control device 9 sets the target battery temperature Tbset (any value within the optimum temperature range of +10°C to +30°C; in the above case, +25°C) transmitted from the battery management system (BMS) 61 as the threshold value, and controls the compressor 44 so that the temperature Tb of the heat medium flowing into the battery 4 does not exceed the threshold value; this will be described in more detail later.

[0062] (2-3) Air conditioning + battery cooling mode First, Figure 6 shows the cooling + battery cooling mode operated by the control device 9. In this cooling + battery cooling mode, the compressor 44, outdoor blower 36, indoor blower 41, and pumps 11 to 13 are also operating, the four-way valve 26 is set to switching mode 1, and the integrated valve 23 is also set to switching mode 1. The three-way valve 24 connects the inlet port to both outlet ports, distributes the heat medium to one outlet port and the other outlet port, and adjusts the amount distributed to each outlet port. Furthermore, the air mix damper 43 is set to a state in which no air is circulated to the indoor heat exchanger 19.

[0063] As a result, the high-temperature refrigerant discharged from the compressor 44 of the refrigerant circuit 3 radiates heat in the radiator 46 to the heat medium flowing in the heating section 16, and in the heat absorber 48, the refrigerant decompressed in the expansion valve 47 evaporates and absorbs heat from the heat medium flowing in the cooling section 17. The refrigerant that has left the heat absorber 48 is separated into gas and liquid in the accumulator 49, and then is sucked into the compressor 44.

[0064] The heat medium discharged from the pump 12 of the first heat medium circuit 6 reaches the heating section 16, where it is heated by the refrigerant (the refrigerant releases heat). The heat medium heated in the heating section 16 flows into the indoor heat exchanger 19. The heat medium leaving this indoor heat exchanger 19 flows into port A of the four-way valve 26, flows out from port C, and flows into the outdoor heat exchanger 22.

[0065] The heat medium that leaves the outdoor heat exchanger 22 flows into port I of the integrated valve 23, flows out from port D, and flows into the travel motor 8. The heat medium that leaves the travel motor 8 flows into port L of the integrated valve 23, flows out from port E, and flows into port B of the four-way valve 26. The heat medium that flows into port B of the four-way valve 26 leaves from port D and repeats the cycle of returning to the pump 12 (indicated by the solid arrows next to the heat medium piping 34 in FIG. 6).

[0066] The heat medium discharged from the pump 11 of the first heat medium circuit 6 reaches the cooling unit 17, where it is cooled by the refrigerant (the refrigerant absorbs heat). The heat medium cooled in the cooling unit 17 flows into the inlet port of the three-way valve 24 and flows out from both outlet ports. Of these, the heat medium that flows out from one of the outlet ports flows into the indoor heat exchanger 18. The heat medium that flows out from the indoor heat exchanger 18 then repeats its circulation, returning to the pump 11 (as indicated by the solid arrows next to the heat medium piping 34 in FIG. 6).

[0067] The heat medium coming out of the other outlet port of the three-way valve 24 flows into port F of the integrating valve 23, exits from port J, passes through the electric heater 33 (not generating heat), and then flows into the heat medium-heat medium heat exchanger 27. The heat medium coming out of the heat medium-heat medium heat exchanger 27 then flows into port C of the integrating valve 23, exits from port B, and returns to the pump 11, repeating this cycle (indicated by the dashed arrows next to the heat medium piping 34 in FIG. 6).

[0068] On the other hand, the heat medium discharged from the pump 13 of the second heat medium circuit 7 flows into the heat radiator 65, where it is cooled by the heat medium of the first heat medium circuit 6 flowing through the heat medium-heat medium heat exchanger 27. The heat medium coming out of the radiator 65 reaches the battery 4, exchanges heat with the battery 4, and then leaves the battery 4 and returns to the pump 13, repeating this cycle (indicated by the solid arrows next to the heat medium piping 35 in FIG. 6).

[0069] As a result, in the air conditioning + battery cooling mode, the heat medium absorbs heat in the indoor heat exchanger 18. Since the air blown into the vehicle compartment flows through the indoor heat exchanger 18, the air cooled by the indoor heat exchanger 18 is blown into the vehicle compartment, thereby cooling the vehicle compartment (the temperature control target). Also, the battery 4 exchanges heat with the heat medium of the second heat medium circuit 7, which has been cooled by the heat medium of the first heat medium circuit 6, in the heat dissipation section 65, and is cooled by absorbing heat.

[0070] In this cooling + battery cooling mode, the control device 9 controls the rotation speed of the compressor 44 so that the temperature Tc of the heat medium in the first heat medium circuit 6 flowing into the indoor heat exchanger 18, detected by the indoor heat exchanger inlet temperature sensor 62, becomes the target temperature of the indoor heat exchanger 18, for example, +5°C. Furthermore, the temperature Tb of the heat medium in the second heat medium circuit 7 flowing into the battery 4, detected by the battery inlet temperature sensor 65, is set to the temperature of the battery 4, and the three-way valve 24 is controlled so that the temperature Tb does not exceed, for example, +25°C within the aforementioned optimum temperature range (+10°C to +30°C). That is, the control device 9 prevents the temperature of the battery 4 from exceeding a predetermined threshold (+25°C). However, the control device 9 controls the three-way valve 24 so that the temperature Tb does not fall below the lower limit (+10°C) of the optimum temperature range.

[0071] In this case, the battery cooling control unit 63 of the control device 9 uses the target battery temperature Tbset transmitted from the battery management system (BMS) 61 as the threshold value and controls the three-way valve 24 so that the temperature Tb of the heat medium flowing into the battery 4 does not exceed the threshold value, which will be described in more detail later.

[0072] (2-4) Switching operation modes The operation mode determination unit 51 of the control device 9 switches between the above-mentioned operation modes based on the outside air temperature detected by the sensor 56, the target value (target heater temperature) TCO of the air temperature on the downwind side of the indoor heat exchanger 19, a battery cooling request sent from the battery management system (BMS) 61, etc.

[0073] As described above, the vehicle thermal management device 1 of the present invention includes the refrigerant circuit 3, the first heat medium circuit 6 in which a heat medium that is cooled by the refrigerant flowing through the refrigerant circuit 3 and exchanges heat with the indoor heat exchanger 18 is circulated, and the second heat medium circuit 7 in which a heat medium that is cooled by the heat medium flowing through the first heat medium circuit 6 and exchanges heat with the battery 4 is circulated. This makes it possible to reduce the number of heat exchangers such as the heat absorber 48 of the refrigerant circuit 3 and the volume of the circuit, thereby simplifying the configuration.

[0074] Furthermore, since the second heat medium circuit 7 for cooling the battery 4 and the first heat medium circuit 6 for air conditioning the vehicle interior are independent, even when an expensive heat medium with high insulating properties is used in the second heat medium circuit 7 as in the embodiment, the amount of the heat medium can be reduced, thereby suppressing an increase in costs.

[0075] Furthermore, since the first heat medium circuit 6 and the second heat medium circuit 7 are independent, it is easy to manage the temperature of the battery 4, and it is also possible to avoid the inconvenience of the battery 4 being excessively cooled due to the air conditioning in the vehicle interior, which will be described later, resulting in condensation. In particular, since the heat medium is circulated through the second heat medium circuit 7 so that the temperature of the battery 4 does not exceed a predetermined threshold, it is possible to effectively suppress the progression of deterioration of the entire battery 4.

[0076] Figure 7 shows the temperature transitions of various parts in the air conditioning + battery cooling mode. In Figure 7, L1 is the temperature inside the vehicle cabin, L2 is the temperature of the air blown into the vehicle cabin from the HVAC unit 38, L3 is the temperature of the heat medium in the first heat medium circuit 6 flowing into the interior heat exchanger 18, and L4 is the temperature of the heat medium in the first heat medium circuit 7 flowing into the battery 4. As is clear from this figure, the temperature (Tb)L4 of the heat medium flowing into the battery 4 is well controlled at around +25°C, and the temperature L1 inside the vehicle cabin is also well regulated.

[0077] In addition, in the embodiment, the first heat medium circuit 6 has an interior heat exchanger 18 for air conditioning the interior of the vehicle, and air-conditions the interior of the vehicle using a heat medium cooled by a refrigerant in a cooling unit 17 (refrigerant-heat medium heat exchanger). Therefore, it is possible to appropriately perform both the air-conditioning of the interior of the vehicle and the cooling of the battery 4 while simplifying the structure and reducing costs.

[0078] Furthermore, in the embodiment, the first heat medium circuit 6 is provided with pumps 11 and 12 for circulating the heat medium within the first heat medium circuit 6, and a three-way valve 24 for distributing the heat medium that has passed through the cooling unit 17 to the indoor heat exchanger 18 and the heat medium-heat medium heat exchanger 27, and the second heat medium circuit 7 is provided with a pump 13 for circulating the heat medium within the second heat medium circuit 7. The circulation of the heat medium in each of the heat medium circuits 6 and 7 is controlled by the pumps 11 to 13 and the three-way valve 24 using the control device 9, so that it is possible to more appropriately cool the battery 4 and air-condition the vehicle interior.

[0079] (3) Start-up control of battery cooling and target battery temperature correction control by the control device 9 As mentioned above, in the battery cooling mode and the air conditioning + battery cooling mode, the control device 9 controls the temperature of the battery 4 so that it does not exceed a threshold value. Next, we will explain the start-up control of battery cooling by the control device 9 and the correction control of the target battery temperature Tbset.

[0080] (3-1) Start-up control of battery cooling As described above, the heat medium of the second heat medium circuit 7 for cooling the battery 4 is cooled by the heat absorber 48 of the refrigerant circuit 3 via the heat medium of the first heat medium circuit 6. Therefore, for example, when switching from the cooling mode to the cooling+battery cooling mode or to the battery cooling mode, there is a concern that the cooling response of the battery 4 may be deteriorated.

[0081] Therefore, when starting to cool the battery 4 in the battery cooling mode or the air conditioning + battery cooling mode, the start-up control unit 64 of the control device 9 increases the rotation speed of the pump 13 more than in the normal state, and increases the amount of heat medium circulating in the second heat medium circuit 7 more than in the normal state. This makes it possible to ensure the start-up performance of the cooling of the battery 4.

[0082] (3-2) Correction control of target battery temperature Tbset Next, a description will be given of correction control of the target battery temperature Tbset by the control device 9. In the air conditioning + battery cooling mode described above, the battery cooling control unit 63 of the control device 9 controls the three-way valve 24 so that the temperature Tb of the heat medium flowing into the battery 4 does not become equal to or higher than the target battery temperature Tbset (threshold value) transmitted from the battery management system (BMS) 61. However, since the heat medium in the first heat medium circuit 6 is cooled according to the target temperature (for example, +5°C) of the indoor heat exchanger 18, when the temperature of the heat medium in the first heat medium circuit 6 becomes lower than the dew-point temperature Td of the outside air, the temperature of the heat medium in the second heat medium circuit 7 cooled by the heat medium in the first heat medium circuit 6 may also become equal to or lower than the dew-point temperature Td of the outside air.

[0083] If such a heat medium is subjected to heat exchange with the battery 4, condensation may occur inside the battery pack, which may cause problems such as a short circuit. Therefore, when the target battery temperature Tbset transmitted from the battery management system (BMS) 61 is equal to or lower than the outside air dew-point temperature Tb, the target battery temperature correction unit 66 of the control device 9 corrects the target battery temperature Tbset so that it is higher than the outside air dew-point temperature Tb.

[0084] Next, an example of correction control of the target battery temperature Tbset by the control device 9 will be described with reference to Fig. 8. Fig. 8 is a flowchart illustrating an example of correction control of the target battery temperature Tbset by the control device 9 in the air conditioning + battery cooling mode. When the control device 9 starts operation in step S1 in Fig. 8, the control device 9 acquires operation information in step S2.

[0085] Next, in step S3, it is determined whether or not there is a battery (BATT) cooling request from the battery management system (BMS) 61. If there is no battery (BATT) cooling request, the current operating mode, for example, cooling mode, is continued in step S4. If the battery 4 temperature rises in the cooling mode, for example, and a battery cooling request is sent from the battery management system (BMS) 61, the control device 9 proceeds from step S3 to step S5, and the target battery temperature correction unit 66 calculates the outside air dew point temperature Td from the outside air temperature and outside air humidity detected by the sensor 56.

[0086] Next, proceed to step S6, compare the target battery (BATT) temperature Tbset sent from the battery management system (BMS) 61 along with the battery cooling request with the calculated dew point temperature Td, and determine whether the target battery temperature Tbset is lower than the outside air dew point temperature Td.

[0087] If the target battery temperature Tbset is higher than the dew-point temperature Td, the target battery temperature correction unit 66 does not correct the target battery temperature Tbset transmitted from the battery management system (BMS) 61, and the control device 9 adopts it as is. Then, the process proceeds to step S7, where the operation mode switching control unit 53 switches the operation mode to the air conditioning + battery cooling mode, and the battery cooling control unit 63 starts cooling control of the battery 4.

[0088] On the other hand, if the target battery temperature Tbset transmitted from the battery management system (BMS) 61 is equal to or lower than the dew-point temperature Td, the target battery temperature correction unit 66 proceeds to step S8 and corrects the target battery temperature Tbset so that it is higher than the dew-point temperature Td. In this case, the correction value is set to be at least equal to or lower than the upper limit (+30°C) of the aforementioned optimum temperature range and equal to or higher than the lower limit (+10°C). Then, the process proceeds to step S7, where the operation mode switching control unit 53 switches the operation mode to the air conditioning + battery cooling mode, and the battery cooling control unit 63 starts cooling control of the battery 4. As a result, the temperature of the heat medium in the second heat exchanger circuit 7 flowing into the battery 4 is controlled to be higher than the dew-point temperature Td, thereby preventing condensation on the battery 4.

[0089] In this way, in this embodiment, the control device 9 is provided with a battery cooling control unit 63 that controls the circulation of the heat medium in each heat medium circuit 6, 7 based on the target battery temperature Tbset, and a target battery temperature correction unit 66 that corrects the target battery temperature Tbset so that it is higher than the outside air dew point temperature Td when the target battery temperature Tbset is equal to or lower than the outside air dew point temperature Td. This makes it possible to effectively prevent condensation from forming on the battery 4 and improve the stability and safety of the device.

[0090] In the embodiment, the control device 9 prevents the temperature of the battery 4 from exceeding a predetermined threshold, but the present invention is not limited to this. The amount of heat medium circulating in the first heat medium circuit 6 and the second heat medium circuit 7, the capacity of each heat exchanger, the heat exchange capacity, etc. may be preset to structurally prevent the temperature of the battery 4 from exceeding the threshold. In this case, the threshold is also set to the optimum temperature range of +10°C to +30°C as described above.

[0091] Furthermore, in the embodiment, the temperature of the battery 4 is controlled so as not to exceed a threshold value. However, in addition to this, or instead of this, control may be performed based on the difference in temperature between the battery cells transmitted from the battery management system (BMS) 61. In this case, the temperature difference between the battery cells is set so as not to exceed a predetermined value. This makes it possible to effectively suppress the deviation in the degree of deterioration caused by the temperature difference within the battery 4.

[0092] In addition, in the embodiment, the temperature Tb of the heat medium flowing into the battery 4 is set as the temperature of the battery 4, and the cooling control of the battery 4 is performed based on this temperature Tb and the target battery temperature Tbset. However, instead of being limited to the temperature Tb, it is also possible to detect the temperature of the battery 4 itself transmitted from the battery management system (BMS) 61, or the temperatures of both the heat medium flowing into and out of the battery 4, and control them as the temperature of the battery 4. [Explanation of symbols]

[0093] EV Electric Vehicle 1. Vehicle thermal management device 2 Heat medium circuit 3 Refrigerant circuit 4 Battery 6 First heat exchanger circuit 7 Second heat exchanger circuit 8. Travel motor (temperature control target) 9 Control Device 10 Power control unit (temperature control target) 11, 12 Pump (first pump) 13 Pump (second pump) 16 Heating section 17 Cooling section (refrigerant-thermal medium heat exchanger) 24 Three-way valve (valve device) 34, 35 Heat medium piping 44 Compressor 46 Heatsink 47 Expansion valve (pressure reducing device) 48 Heat absorber 61 Battery Management System 62 Indoor heat exchanger inlet temperature sensor 63 Battery cooling control unit 65 Battery inlet temperature sensor 64 Start-up control section 66 Target battery temperature correction unit

Claims

1. a first heat medium circuit through which a heat medium that is cooled by a refrigerant flowing through the refrigerant circuit and that exchanges heat with a temperature control target other than a battery is circulated; and a second heat medium circuit through which a heat medium that is cooled by a heat medium flowing through the first heat medium circuit and that exchanges heat with the battery is circulated, a heat medium circulating through the second heat medium circuit so that the temperature difference within the battery does not exceed a predetermined value, or so that the temperature of the battery does not exceed a predetermined threshold value.

2. The refrigerant circuit includes a compressor that compresses the refrigerant, a radiator that radiates heat from the high-temperature refrigerant discharged from the compressor, a pressure reducing device that reduces the pressure of the refrigerant that has radiated heat in the radiator, and a heat absorber that absorbs heat from the refrigerant that has been decompressed in the pressure reducing device. the first heat medium circuit has a refrigerant-heat medium heat exchanger that exchanges heat with the heat absorber, a heat exchanger for the temperature control target, and a heat medium-heat medium heat exchanger; 2. The vehicle thermal management device according to claim 1, wherein the second heat medium circuit has a heat radiating portion that exchanges heat with the heat medium-heat medium heat exchanger.

3. The heat exchanger for the temperature control object provided in the first heat medium circuit is an interior heat exchanger for air conditioning the interior of the vehicle, and the interior of the vehicle is air-conditioned using a heat medium cooled by a refrigerant in the refrigerant-heat medium heat exchanger.

4. The first heat medium circuit includes a first pump that circulates a heat medium within the first heat medium circuit, and a valve device that distributes the heat medium that has passed through the refrigerant-heat medium heat exchanger to the heat exchanger for the temperature control target and the heat medium-heat medium heat exchanger; the second heat medium circuit has a second pump that circulates the heat medium within the second heat medium circuit, 4. The vehicle thermal management device according to claim 2, further comprising a control device that controls the circulation of the heat medium in each of the heat medium circuits by each of the pumps and the valve devices.

5. a control device that controls the circulation of the heat medium in each of the heat medium circuits, The control device 2. The vehicle thermal management device according to claim 1, further comprising a start-up control section that increases the amount of heat medium circulating through the second heat medium circuit when cooling of the battery starts, compared to a steady state.

6. The control device a battery cooling control unit that controls the circulation of the heat medium in each of the heat medium circuits based on a predetermined target battery temperature; a target battery temperature correction unit that corrects the target battery temperature to be higher than the dew-point temperature of outside air when the target battery temperature is equal to or lower than the dew-point temperature of outside air; 6. The vehicle thermal management system of claim 5, further comprising:

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