Heat management system and vehicle

Abstract

To provide a heat management system that can flow a heat medium into a passage separated from a reserve tank as necessary, while reducing amounts of air bubbles in the heat medium, and a vehicle.SOLUTION: A heat management system comprises: a first passage not provided with a reserve tank; a second passage provided with a reserve tank; a switching device that is configured to switch between connection and disconnection between the first passage and the second passage; and a control device that controls the switching device. The control device is configured to flow the heat medium into the first passage and the second passage connected by the switching device, when a predetermined connection condition is satisfied. Further, the control device is configured to determine whether air bubbles more than acceptable amounts exist in the heat media or not. When the control device determines that the air bubbles more than the acceptable amounts exist in the heat media, the unsatisfied connection condition becomes satisfied.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present disclosure relates to thermal management systems and vehicles. [Background technology]

[0002] JP 2023-063735 A (Patent Document 1) discloses a temperature control system including a coolant circuit. This coolant circuit includes first to fifth paths through which the coolant flows, a five-way valve, and a reserve tank. One end of each of the first to fifth paths is connected to the five-way valve, and the other end is connected to the reserve tank. The five-way valve switches the connection of the cooling paths so that the coolant input from at least one of the third path and the fifth path is output to at least one of the first path, the second path, and the fourth path. A radiator is connected to the first path, and the second path bypasses the radiator. A PCU (Power Control Unit) and a water pump are connected to the third path, a battery is connected to the fourth path, and a chiller and a water pump are connected to the fifth path. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-063735 Summary of the Invention [Problem to be solved by the invention]

[0004] In the system described in Patent Document 1, the first to fifth paths through which a heat transfer medium, such as a coolant, flows are all connected to a reserve tank. However, depending on the vehicle structure, it may be difficult to connect all of the paths (flow paths) that can be connected by a switching device (e.g., a five-way valve) to the reserve tank. In such a vehicle thermal management system, the multiple flow paths that can be connected by the switching device may include a flow path that is separated from the reserve tank. However, in a flow path that is separated from the reserve tank, air bubbles are likely to be generated and / or remain in the heat transfer medium flowing through that flow path. If the amount of air bubbles in the heat transfer medium increases, deterioration and / or overspeed of the pump that circulates the heat transfer medium will be accelerated.

[0005] The present disclosure has been made to solve the above-mentioned problems, and its purpose is to provide a thermal management system and a vehicle that can reduce the amount of bubbles in the heat transfer medium while allowing the heat transfer medium to flow through a flow path separated from the reserve tank as needed. [Means for solving the problem]

[0006] According to an embodiment of a first aspect of the present disclosure, there is provided a thermal management system as follows. (Item 1) The thermal management system includes a first flow path without a reserve tank, a second flow path with a reserve tank, a switching device configured to switch between connection and disconnection of the first flow path and the second flow path, and a control device that controls the switching device. The control device is configured to circulate a heat medium through the first flow path and the second flow path connected by the switching device when a predetermined connection condition is met. The control device is also configured to determine whether or not there are more bubbles in the heat medium than the allowable amount. When the control device determines that there are more bubbles in the heat medium than the allowable amount, the connection condition is switched from not met to met.

[0007] The thermal management system described above includes a switching device that switches between connection and disconnection of the first and second flow paths, making it easy to perform appropriate thermal management depending on the situation. However, when the first flow path is disconnected from the reserve tank, bubbles may occur in the heat transfer medium in the first flow path. Therefore, the control device circulates the heat transfer medium through the connected first and second flow paths when a predetermined connection condition is met. By connecting the first flow path to the second flow path provided with the reserve tank, air is purged from the heat transfer medium in the first flow path. The control device also determines whether the heat transfer medium contains more air bubbles than the allowable amount. When the control device determines that the heat transfer medium contains more air bubbles than the allowable amount, the connection condition is switched from not being met to being met. This facilitates air purging of the heat transfer medium at an appropriate frequency. In this way, the thermal management system described above makes it possible to reduce the amount of air bubbles in the heat transfer medium while purging the heat transfer medium through the flow path disconnected from the reserve tank as needed.

[0008] The thermal management system described in the above paragraph 1 may have the configuration described in any one of paragraphs 2 to 9 below.

[0009] (Item 2) In the thermal management system described in item 1, when the connection condition is met, the switching device is prohibited from disconnecting the first flow path from the second flow path, and when the connection condition is not met, the switching device is permitted to disconnect the first flow path from the second flow path.

[0010] According to the above configuration, when the connection condition is met, the first flow path and the second flow path are maintained in a connected state. This makes it easier to properly bleed air from the heat medium. Furthermore, when the connection condition is not met, the first flow path and the second flow path can be disconnected. This makes it easier to properly manage the heat of the vehicle. When the connection condition is not met, the control device may switch between connecting and disconnecting the first flow path and the second flow path depending on, for example, the state of the vehicle.

[0011] (Item 3) The thermal management system according to item 1 or 2 further includes a pump that circulates the heat medium through the first flow path. The control device is configured to detect overspeed of the pump based on a state of the pump. The control device is configured to determine that an unacceptable amount of air bubbles is present in the heat medium when overspeed of the pump is detected.

[0012] According to the above configuration, the control device can accurately and easily determine whether or not the heat medium contains more air bubbles than the allowable amount.

[0013] (4) The thermal management system according to any one of paragraphs 1 to 3 further includes a temperature sensor for detecting the temperature of the heat medium. The control device is configured to determine whether or not an amount of bubbles exceeding an allowable amount is present in the heat medium based on whether or not a trajectory length of the value detected by the temperature sensor is equal to or greater than a predetermined value.

[0014] According to the above configuration, the control device can accurately and easily determine whether or not the heat medium contains more air bubbles than the allowable amount.

[0015] (Item 5) In the thermal management system described in any one of Items 1 to 4, the control device determines whether or not the deaeration of the heat medium is completed during the period in which the connection condition is satisfied. Then, when it is determined that the deaeration of the heat medium is completed, the connection condition is switched from satisfied to not satisfied.

[0016] According to the above configuration, when the control device determines that the heat medium contains more air bubbles than the allowable amount, air bleeding (connection of the first flow path and the second flow path) is performed. Then, when air bleeding of the heat medium is completed, it is possible to disconnect the first flow path and the second flow path. This makes it easier to appropriately manage the heat of the vehicle while reducing the amount of air bubbles in the heat medium.

[0017] (Item 6) In the thermal management system described in item 5, the control device determines that the air removal from the heat medium is completed when a predetermined time has elapsed since the connection condition was met.

[0018] According to the above configuration, it is possible to easily and appropriately determine whether or not the air bleeding from the heat medium has been completed.

[0019] (Item 7) In the thermal management system described in item 5, the control device determines that deaeration of the heat medium is complete when it is determined that there are no more air bubbles in the heat medium than the allowable amount.

[0020] According to the above configuration, it is possible to easily and appropriately determine whether or not the air bleeding from the heat medium has been completed.

[0021] (Item 8) In the thermal management system described in any one of Items 1 to 4, when a predetermined time has elapsed since the connection condition was met, the connection condition is switched from met to not met. The predetermined time is shorter as the temperature of the heating element provided in the second flow path is higher.

[0022] According to the above configuration, it becomes easier to achieve both cooling of the heat generating element and air removal from the heat medium. (Item 9) In the thermal management system described in any one of items 1 to 8, the switching device includes at least one of a four-way valve, a five-way valve, a six-way valve, a seven-way valve, an eight-way valve, a nine-way valve, and a ten-way valve.

[0023] According to the above switching device, it becomes easier to appropriately switch between connection and disconnection of the first flow path and the second flow path.

[0024] According to an embodiment of the second aspect of the present disclosure, there is provided a vehicle as follows. (10) The vehicle includes the thermal management system according to any one of the first to ninth paragraphs.

[0025] The vehicle described above can reduce the amount of bubbles in the heat medium by using the thermal management system described above, and can cause the heat medium to flow through a flow path separated from the reserve tank as needed.

[0026] (Item 11) In the vehicle described in item 10, the first flow path is configured to be able to cool a first heating element mounted on the vehicle with a heat medium. The second flow path includes a cooling path that can cool a second heating element mounted on the vehicle with a heat medium and a bypass path that bypasses the second heating element. The switching device is configured to be able to switch between the cooling path and the bypass path.

[0027] According to the above configuration, it becomes easier to appropriately manage the heat of each of the first heating element and the second heating element mounted on the vehicle.

[0028] (Item 12) In the vehicle described in item 11, the second heating element includes a power storage device. The first heating element includes a component that receives a supply of electric power from the power storage device. The control device is configured to connect the first flow path and the cooling path of the second flow path using the switching device when the connection condition is met and the temperature of the heat medium in the first flow path is lower than a predetermined temperature, and to circulate the heat medium through the first flow path and the cooling path. The control device is also configured to connect the first flow path and the bypass path of the second flow path using the switching device when the connection condition is met and the temperature of the heat medium in the first flow path exceeds a predetermined temperature, and to circulate the heat medium through the first flow path and the bypass path.

[0029] Onboard components receiving power from the power storage device tend to generate heat, which can raise the temperature of the heat medium in the first flow path. If the temperature of the heat medium in the first flow path rises excessively, it becomes difficult for the heat medium to cool the power storage device when the first flow path and the second flow path are connected. Conversely, the heat medium may raise the temperature of the power storage device. Therefore, in the above configuration, the cooling path and the bypass path are switched depending on the temperature of the heat medium in the first flow path. This makes it easier to properly manage the heat of the power storage device. [Effects of the Invention]

[0030] According to the present disclosure, it is possible to provide a thermal management system and a vehicle that can reduce the amount of bubbles in the heat medium while allowing the heat medium to flow through a flow path separated from the reserve tank as needed. [Brief explanation of the drawings]

[0031] [Figure 1] 1 is a diagram illustrating a configuration of a thermal management system according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 is a diagram illustrating an example of the configuration of a thermal management circuit according to the first embodiment. [Figure 3] 1 is a diagram showing a vehicle to which a thermal management system according to a first embodiment is applied. [Figure 4] FIG. 2 is a diagram illustrating a disconnected mode of the thermal management system according to the first embodiment. [Figure 5] FIG. 2 is a diagram illustrating a first connection mode of the thermal management system according to the first embodiment. [Figure 6] FIG. 4 is a diagram illustrating a second connection mode of the thermal management system according to the first embodiment. [Figure 7] 4 is a flowchart showing air bleeding control in the first embodiment. [Figure 8] FIG. 10 is a diagram for explaining a first air bubble determination method. [Figure 9] FIG. 10 is a diagram for explaining a second air bubble determination method. [Figure 10] 8 is a flowchart showing a modified example of the control shown in FIG. 7. [Figure 11] 10A and 10B are diagrams for explaining a modified example of a method for setting a threshold value used to determine the completion of air bleeding. [Figure 12] FIG. 10 is a diagram illustrating a configuration of a thermal management system according to a second embodiment of the present disclosure. [Figure 13] FIG. 10 is a diagram illustrating a disconnected mode of the thermal management system according to the second embodiment. [Figure 14] FIG. 10 is a diagram illustrating a coupled mode of the thermal management system according to the second embodiment. [Figure 15] 10 is a flowchart showing air bleeding control in the second embodiment. [Figure 16] 16 is a flowchart showing a modified example of the control shown in FIG. 15. [Figure 17] 1. FIG. 4 is a diagram showing a first modified example of the configuration of the thermal management system shown in FIG. [Figure 18] 18 illustrates the thermal management system shown in FIG. 17 in a decoupled mode. [Figure 19] 18 illustrates a first coupling mode of the thermal management system illustrated in FIG. 17. [Figure 20] 18 illustrates a second coupling mode of the thermal management system illustrated in FIG. 17. [Figure 21] FIG. 18 illustrates a third coupling mode of the thermal management system illustrated in FIG. [Figure 22] 1. FIG. 4 is a diagram illustrating a second variation of the thermal management system configuration shown in FIG. 1 in a disconnected mode. [Figure 23] 23 illustrates a first coupling mode of the thermal management system illustrated in FIG. 22. [Figure 24] 23 illustrates a second coupling mode of the thermal management system illustrated in FIG. 22. [Figure 25] 23 illustrates a third coupling mode of the thermal management system illustrated in FIG. 22. DETAILED DESCRIPTION OF THE INVENTION

[0032] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present disclosure will be described in detail with reference to the accompanying drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals and the description thereof will not be repeated.

[0033] [First embodiment] Fig. 1 is a diagram showing the overall configuration of a thermal management system according to the first embodiment. Fig. 2 is a diagram showing the configuration of a thermal management circuit according to the first embodiment. As shown in Fig. 1, the thermal management system 1 includes a thermal management circuit 100, an ECU (Electronic Control Unit) 500, and an HMI (Human Machine Interface) 600.

[0034] Referring to FIG. 2 in conjunction with FIG. 1, the thermal management circuit 100 includes a high-temperature flow path 110, a radiator 120, a low-temperature flow path 130, a condenser 140, a refrigeration cycle flow path 150, a chiller 160, a battery flow path 170, and a five-way valve 180.

[0035] The high-temperature flow path 110 and the refrigeration cycle flow path 150 are separate from each other and do not communicate with each other. The high-temperature flow path 110 and the low-temperature flow path 130 are also separate from each other and do not communicate with each other. However, the high-temperature flow path 110 and the refrigeration cycle flow path 150 are connected to each other via a condenser 140 so that they can exchange heat with each other. The condenser 140 is connected to both the high-temperature flow path 110 and the refrigeration cycle flow path 150. The high-temperature flow path 110 and the low-temperature flow path 130 are also connected to each other via a radiator 120 so that they can exchange heat with each other. The radiator 120 is connected to both the high-temperature flow path 110 and the low-temperature flow path 130. As shown in FIG. 2, the radiator 120 includes a high-temperature (HT) radiator 121 and a low-temperature (LT) radiator 122.

[0036] The refrigeration cycle path 150 and the battery path 170 are separate from each other and do not communicate with each other. However, the refrigeration cycle path 150 and the battery path 170 are connected to each other via a chiller 160 so that they can exchange heat with each other. The chiller 160 is connected to both the refrigeration cycle path 150 and the battery path 170.

[0037] The five-way valve 180 has five ports P1 to P5. The five-way valve 180 is configured to be able to switch between connection (communication) and disconnection (non-communication) of the low-temperature flow path 130 and the battery flow path 170. The low-temperature flow path 130 is not provided with a reserve tank (R / T). The battery flow path 170 is provided with a reserve tank 162. The five-way valve 180 is controlled by the ECU 500. The five-way valve 180, the low-temperature flow path 130, the battery flow path 170, and the ECU 500 are examples of the "switching device," "first flow path," "second flow path," and "control device" according to the present disclosure, respectively.

[0038] The high-temperature flow path 110 includes flow paths 110a, 110b, and 110c. A three-way valve 113 and a reserve tank 115 are provided in the high-temperature flow path 110. One end of each of the flow paths 110a, 110b, and 110c is connected to the three-way valve 113, and the other end is connected to the reserve tank 115. A high-temperature radiator 121 is provided in the flow path 110a. A heater core 114 is provided in the flow path 110b. A pump 111, an electric heater 112, and a condenser 140 are provided in the flow path 110c.

[0039] One end of the low-temperature flow path 130 is connected to a port P3 of the five-way valve 180, and the other end of the low-temperature flow path 130 is connected to a port P5 of the five-way valve 180. The low-temperature flow path 130 is provided with a pump 131, an SPU (Smart Power Unit) 132, a PCU (Power Control Unit) 133, an oil cooler (O / C) 134, and a step-up / step-down converter 135.

[0040] Various devices that adjust the temperature by a refrigeration cycle (i.e., a cycle of an evaporation stroke, a compression stroke, a condensation stroke, and an expansion stroke) are provided in the refrigeration cycle flow path 150. More specifically, the refrigeration cycle flow path 150 is provided with a compressor 151, an expansion valve 152, an evaporator 153, an EPR (Evaporative Pressure Regulator) 154, and an expansion valve 155.

[0041] The battery flow path 170 includes flow paths 170a, 170b, and 170c. One end of each of the flow paths 170a, 170b, and 170c is connected to the five-way valve 180, and the other end is connected to the reserve tank 162. Specifically, one end of the flow paths 170a, 170b, and 170c is connected to ports P2, P4, and P1 of the five-way valve 180, respectively. A battery 171 and an electric heater 172 are provided in the flow path 170a. The electric heater 172 heats at least one of the heat medium in the flow path 170a and the battery 171. A pump 161 is provided in the flow path 170c. The flow path 170b is provided so as to bypass the flow path 170a. The five-way valve 180 is configured to be able to switch between the flow paths 170a and 170b. When the five-way valve 180 connects the flow path 170b to the low-temperature flow path 130, the heat medium flowing from the low-temperature flow path 130 into the five-way valve 180 flows into the reserve tank 162, avoiding the flow path 170a (including the battery 171) (see FIG. 6, which will be described later). In this embodiment, the flow path 170a functions as a cooling path that can cool the battery 171 with the heat medium. In addition, the flow path 170b functions as a bypass path that bypasses the battery 171.

[0042] A first heat medium flows through the high-temperature flow path 110. A second heat medium flows through the refrigeration cycle flow path 150. A third heat medium flows through each of the low-temperature flow path 130 and the battery flow path 170. In this embodiment, a heat medium (third heat medium) of the same type as the heat medium flowing through the low-temperature flow path 130 flows through the battery flow path 170. A known heat medium can be used as each of the first to third heat mediums. Examples of the second heat medium include hydrofluorocarbon refrigerants such as R-134a, hydrofluoroolefin refrigerants such as R-1234yf, carbon dioxide (CO2) such as R744, and propane gas. In this embodiment, a liquid heat medium (e.g., water or a coolant other than water) is used as each of the first and third heat mediums. Examples of coolants other than water include insulating oil and antifreeze such as LLC (Long Life Coolant). In this embodiment, each of the pumps 111, 131, and 161 is a water pump (W / P). The ECU 500 executes PWM (Pulse Width Modulation) control of each pump using a pump drive signal. The pump drive signal indicates a duty ratio (the ratio of a high-level period to a cycle) of a drive instruction (a high-level / low-level drive signal) for the pump.

[0043] As shown in FIG. 2, the pumps 111, 131, and 161 are provided with pump sensors PS1, PS2, and PS3, respectively. Each of the pump sensors PS1 to PS3 is configured to detect the state (e.g., rotation speed, current, and temperature) of the corresponding pump. The high-temperature flow path 110, the low-temperature flow path 130, the refrigeration cycle flow path 150, and the battery flow path 170 are provided with flow path sensors T1, T2, T3, and T4, respectively. Each of the flow path sensors T1 to T4 includes a temperature sensor that detects the temperature of the heat medium in the corresponding flow path, and a flow rate sensor that measures the flow rate of the heat medium flowing through the corresponding flow path. The battery 171 is provided with a BMS (Battery Management System) 173 that monitors the state of the battery 171. The BMS 173 includes various sensors that detect the state (e.g., voltage, current, and temperature) of the battery 171, and outputs the detection results to the ECU 500. In addition to the above-described sensor function, the BMS 173 may further have at least one of a SOC (State Of Charge) estimation function and a SOH (State of Health) estimation function.

[0044] The ECU 500 acquires detection results (sensor values) from various sensors included in the thermal management circuit 100 and controls various devices included in the thermal management circuit 100. The ECU 500 includes a processor 501, a random access memory (RAM) 502, and a storage device 503. An example of the processor 501 is a central processing unit (CPU). The ECU 500 may include one processor or two or more processors. The storage device 503 is configured to be able to save stored information. The storage device 503 may include at least one of a hard disk drive (HDD), a solid state drive (SSD), and a non-volatile memory. The ECU 500 also has a timekeeping function (timer). This timekeeping function may be implemented by hardware (a timer circuit) or software.

[0045] The storage device 503 of the ECU 500 stores programs as well as various types of information used by the programs. In this embodiment, various controls are performed by the processor 501 executing the programs stored in the storage device 503. However, these processes may be performed only by hardware (for example, a logic circuit such as wired logic) without using software.

[0046] The HMI (Human Machine Interface) 600 functions as an interface between the user and the ECU 500. The HMI 600 includes an input device and a notification device. The input device accepts user operations. The notification device notifies the user by display or sound (including voice). The HMI 600 may be an in-vehicle HMI or a mobile terminal that can be carried by the user.

[0047] FIG. 3 is a diagram showing an example of the configuration of a vehicle equipped with the thermal management system according to the first embodiment. Referring to FIGS. 1 to 3, the vehicle 10 is an electric vehicle (xEV) equipped with the thermal management circuit 100 and ECU 500 described above. The vehicle 10 is configured to be able to run using power output from a battery 171 (driving battery). The battery 171 may include a secondary battery such as a lithium-ion battery, a nickel-metal hydride battery, or a sodium-ion battery. The type of the secondary battery may be a liquid secondary battery or an all-solid-state secondary battery. A plurality of secondary batteries may form a battery pack. Another power storage device (e.g., an electric double layer capacitor) may be used instead of the secondary battery. The vehicle 10 is, for example, an electric vehicle (BEV) without an internal combustion engine. However, the vehicle 10 is not limited thereto, and may be a PHEV (plug-in hybrid vehicle) equipped with an internal combustion engine, or another electric vehicle (xEV).

[0048] The vehicle 10 further includes an SMR (System Main Relay) 11, an inlet 12, a charging relay 13, a communication device 14, an MG (Motor Generator) 21, a gearbox 22, an EOP (Electric Oil Pump) 23, an oil circuit 24, wheel speed sensors 25, an auxiliary battery 30, and an air conditioner 40. The voltage of the battery 171 is higher than the voltage of the auxiliary battery 30. The battery 171 applies a voltage to a high-voltage power supply line PL1. The auxiliary battery 30 is a low-voltage power supply for the auxiliary devices and applies a voltage to a low-voltage power supply line PL2. The air conditioner 40 is connected to the high-voltage power supply line PL1 and receives a supply of power from the battery 171. In the vehicle 10, the heating circuit of the air conditioner 40 constitutes a high-temperature flow path 110 (FIG. 2), and the cooling circuit of the air conditioner 40 constitutes a refrigeration cycle flow path 150 (FIG. 2). The SMR 11 , the charging relay 13 , the EOP 23 , the air conditioner 40 , the PCU 133 , the step-up / step-down converter 135 , and the electric heater 172 are controlled by the ECU 500 .

[0049] The SMR 11 is a relay located between the battery 171 and the PCU 133. The MG 21 functions as a drive motor and rotates the drive wheels of the vehicle 10. The PCU 133 is connected to the high-voltage power supply line PL1 and drives the MG 21 using power supplied from the battery 171. The PCU 133 includes, for example, an inverter. The gearbox 22 includes, for example, a reducer and a differential gear device. The MG 21 converts power into torque. This torque is transmitted to the drive wheels of the vehicle 10 via the gearbox 22. The MG 21 also generates regenerative power, for example, when the vehicle 10 is decelerating, to charge the battery 171.

[0050] The wheel speed sensor 25 is provided on a wheel of the vehicle 10 or on an axle that rotates in conjunction with the wheel, and detects the rotation speed of the wheel. A wheel speed sensor 25 may be provided for each wheel. The wheel speed sensor 25 outputs the detection result to the ECU 500. The ECU 500 calculates the traveling speed (vehicle speed) of the vehicle 10 based on the detection signal of the wheel speed sensor 25.

[0051] The EOP 23 circulates the lubricating oil through the oil circuit 24. The oil cooler 134 is connected to both the low-temperature flow path 130 and the oil circuit 24 and functions as a heat exchanger. The oil cooler 134 cools the lubricating oil in the oil circuit 24 using a heat medium flowing through the low-temperature flow path 130. The oil circuit 24 supplies the lubricating oil to the MG 21 and the gear box 22, and the MG 21 and the gear box 22 are cooled by the lubricating oil. However, this is not a limitation, and the cooling method around the motor can be changed as appropriate. For example, one of the MG 21 and the gear box 22 may be oil-cooled by the oil circuit 24, and the other may be water-cooled by the low-temperature flow path 130.

[0052] The step-up / step-down converter 135 is connected to the high-voltage power supply line PL1 and transforms DC power between the battery 171 and the auxiliary battery 30. The step-up / step-down converter 135 includes a DC / DC converter. The step-up / step-down converter 135 steps down the DC power from the battery 171 and outputs it to the auxiliary battery 30. The auxiliary battery 30 supplies power to on-board devices (such as a pump, a compressor, a heater, a valve, and an ECU) connected to the low-voltage power supply line PL2.

[0053] The vehicle 10 is configured to be able to perform external charging (charging the battery 171 with power from outside the vehicle). The SPU 132 is provided on the charging line CHL and functions as an on-board charger (charging circuit). The SPU 132 may also function as an ESU (Electric Supply Unit). The charging relay 13 switches between connection and disconnection of the charging line CHL. The ECU 500 connects the charging relay 13 before starting external charging and controls the SPU 132 while external charging is being performed. When the tip (connector) of a charging cable connected to an EVSE (Electric Vehicle Supply Equipment) 800 is connected (plugged in) to an inlet 12 of the parked vehicle 10, the vehicle 10 is electrically connected to the EVSE 800. The vehicle 10 can charge the battery 171 using power input from the EVSE 800 to the inlet 12. In the example shown in FIG. 3 , one end of the charging line CHL is connected between the SMR 11 and the PCU 133, and the other end is connected to the inlet 12. However, the present invention is not limited to this, and one end of the charging line CHL may be connected between the battery 171 and the SMR 11.

[0054] The multiple on-board devices shown in FIG. 3 may be integrated as an electric axle (eAxle) with an "Xin1" structure. Examples of the "Xin1" structure include a "3-in-1" structure in which a drive motor, inverter, and gearbox are integrated, a "6-in-1" structure in which a DC / DC converter, on-board charger, and BMS are integrated, and an "8-in-1" structure in which a power distribution unit (PDU) and ECU are integrated. An electric axle may be provided at each of the front and rear of the vehicle 10. The low-temperature flow path 130 may be configured to be able to cool these electric axles.

[0055] In the vehicle 10, the PCU 133 is cooled by the heat medium flowing through the low-temperature flow path 130. Furthermore, the lubricating oil in the oil circuit 24 is cooled by the heat medium flowing through the low-temperature flow path 130, and the MG 21 is cooled by the lubricating oil. In this way, the low-temperature flow path 130 is configured to be able to cool the MG 21 and the PCU 133 by the heat medium. Furthermore, the cooling path (flow path 170a) of the battery flow path 170 is configured to be able to cool the battery 171 by the heat medium. The battery 171 is an electricity storage device that stores electric power for propelling the vehicle 10, and is an example of a "second heating element" according to the present disclosure. The MG 21 and the PCU 133 are each an on-vehicle component that receives a supply of electric power from the battery 171, and are an example of a "first heating element" according to the present disclosure.

[0056] The HMI 600A is an HMI (in-vehicle HMI) mounted on the vehicle 10 and can function as the HMI 600 shown in FIG. 1. The HMI 600A may include at least one of an instrument panel, a navigation system, a center display, and a head-up display. The HMI 600A may further include a smart speaker that accepts voice input, or a display device that provides an augmented reality (AR) display.

[0057] The mobile terminal 600B is a terminal carried by the user of the vehicle 10 and can function as the HMI 600 shown in FIG. 1. The ECU 500 performs wireless communication with the mobile terminal 600B via the communication device 14. The mobile terminal 600B is, for example, a smartphone equipped with a touch panel display. However, the mobile terminal 600B is not limited to this, and a laptop, a portable game console, a wearable device (for example, a smart watch, smart glasses, or smart clothing), an electronic key, or the like can also be adopted as the mobile terminal 600B.

[0058] In this embodiment, the thermal management system 1 is configured to use a heat medium to perform thermal management of the vehicle 10. Specifically, the thermal management system 1 can operate in a number of modes, including a decoupled mode, a first coupled mode, and a second coupled mode, which will be described below.

[0059] FIG. 4 is a diagram illustrating the disconnection mode of the thermal management system 1. Referring to FIG. 4, in the disconnection mode, in the five-way valve 180, port P1 is connected to port P2, and port P3 is connected to port P5. Port P4 is not connected to any other port. This forms circuits C11 and C12 that are separated from each other. Circuit C11 is a fluid circuit in which port P5, the low-temperature flow path 130, and port P3 are continuously connected. In the disconnection mode, the pump 131 is driven to circulate the heat medium through the circuit C11. As a result, the heat medium that flows from the low-temperature flow path 130 to port P3 is output from port P5 to the low-temperature flow path 130. Circuit C12 is a fluid circuit in which port P2, the flow path 170a, the reserve tank 162, the flow path 170c, and port P1 are continuously connected. In the disconnection mode, the pump 161 is also driven to circulate the heat medium through the circuit C12. As a result, the heat medium that has flowed from the flow path 170c to the port P1 is output from the port P2 to the flow path 170a. In the disconnection mode, the circuit C11 (including the low-temperature flow path 130) is disconnected from the reserve tank. Therefore, the heat medium (third heat medium) in the low-temperature flow path 130 is not bled.

[0060] FIG. 5 is a diagram illustrating the first connection mode of the thermal management system 1. Referring to FIG. 5, in the first connection mode, in the five-way valve 180, port P1 is connected to port P5, and port P2 is connected to port P3. Port P4 is not connected to any other port. This forms a circuit C21. The circuit C21 is a fluid circuit that continuously connects port P5, the low-temperature flow path 130, port P3, port P2, the flow path 170a, the reserve tank 162, the flow path 170c, and port P1. In the first connection mode, the pumps 131 and 161 are driven, causing the heat medium to circulate through the circuit C21. As a result, the heat medium that flows from the low-temperature flow path 130 into port P3 is output from port P2 to flow path 170a, passes through flow path 170a, the reserve tank 162, and flow path 170c, and flows into port P1. Furthermore, the heat medium that has flowed into port P1 is output from port P5 to the low-temperature flow path 130. In the first connection mode, the five-way valve 180 connects the cooling path (flow path 170a) of the battery flow path 170 to the low-temperature flow path 130. By connecting the low-temperature flow path 130 to the battery flow path 170 in which the reserve tank 162 is provided, air is bled from the heat medium (third heat medium) in the low-temperature flow path 130. Note that the ECU 500 may stop the pump 161 in the first connection mode.

[0061] FIG. 6 is a diagram illustrating a second connection mode of the thermal management system 1. Referring to FIG. 6, in the second connection mode, in the five-way valve 180, port P1 is connected to port P5, and port P3 is connected to port P4. Port P2 is not connected to any other port. This forms a circuit C22. Circuit C22 is a fluid circuit that continuously connects port P5, the low-temperature flow path 130, port P3, port P4, flow path 170b, reserve tank 162, flow path 170c, and port P1. In the second connection mode, the pumps 131 and 161 are driven, causing the heat medium to circulate through circuit C22. As a result, the heat medium that flows from the low-temperature flow path 130 to port P3 is output from port P4 to flow path 170b, passes through flow path 170b, reserve tank 162, and flow path 170c, and flows into port P1. Furthermore, the heat medium that has flowed into port P1 is output from port P5 to the low-temperature flow path 130. In the second connection mode, the five-way valve 180 connects the bypass path (flow path 170b) of the battery flow path 170 to the low-temperature flow path 130. By connecting the low-temperature flow path 130 to the battery flow path 170 in which the reserve tank 162 is provided, air is bled from the heat medium (third heat medium) in the low-temperature flow path 130. Note that the ECU 500 may stop the pump 161 in the second connection mode.

[0062] The ECU 500 switches between a disconnection mode, a first connection mode, and a second connection mode by controlling the five-way valve 180. When the low-temperature flow path 130 and the battery flow path 170 are disconnected by the five-way valve 180 (disconnection mode), the ECU 500 causes the pump 131 provided in the low-temperature flow path 130 to circulate the heat medium through the low-temperature flow path 130, and causes the pump 161 provided in the battery flow path 170 to circulate the heat medium through the battery flow path 170 (see FIG. 4). When the low-temperature flow path 130 and the battery flow path 170 are connected by the five-way valve 180 (first or second connection mode), the ECU 500 causes the pumps 131, 161 to circulate the heat medium through the low-temperature flow path 130 and the battery flow path 170 (see FIGS. 5 and 6). This configuration makes it easier to appropriately circulate the heat medium through each of the low-temperature flow path 130 and the battery flow path 170 in any of the disconnection mode, the first connection mode, and the second connection mode. Note that instead of the five-way valve 180, another multi-way valve (for example, a six-way valve, a seven-way valve, an eight-way valve, a nine-way valve, or a ten-way valve) may be used as the switching device. The switching device may also be configured by a plurality of multi-way valves.

[0063] In the vehicle 10, the heat medium (third heat medium) flowing through the low-temperature flow path 130 and the battery flow path 170 is replaced as needed. For example, the third heat medium may be replaced when a predetermined period of time (e.g., 15 to 20 years) has elapsed since the initial state (new vehicle). Furthermore, when an on-board component (e.g., SPU 132) provided in the low-temperature flow path 130 is replaced, the third heat medium may also be replaced at the same time. For example, at a dealer or a factory, an operator drains the old third heat medium from the vehicle 10 and injects the new third heat medium into the vehicle 10. This replaces the old third heat medium with the new third heat medium. The injected new third heat medium (replaced third heat medium) contains fine air particles that tend to gather and form clumps while the vehicle 10 is running. Air pockets in the heat medium can cause a decrease in the cooling performance of the heat medium. Furthermore, large air pockets in the heat medium can cause the pump that circulates the heat medium to deteriorate and / or overspeed.

[0064] Therefore, in the vehicle 10, the ECU 500 is configured to circulate the heat medium (third heat medium) through the low-temperature flow path 130 and the battery flow path 170, which are connected by the five-way valve 180, when a predetermined connection condition is met. Specifically, when the connection condition is met, the ECU 500 operates the thermal management system 1 in a first connection mode (FIG. 5) or a second connection mode (FIG. 6). As will be described in detail later, the ECU 500 determines whether or not an amount of air bubbles exceeding the allowable amount is present in the heat medium (third heat medium). When the ECU 500 determines that an amount of air bubbles exceeding the allowable amount is present in the heat medium, the connection condition is switched from not being met to being met. This makes it easier to bleed air from the heat medium at an appropriate frequency. More specifically, when the ECU 500 has not detected the presence of air bubbles in the heat medium (i.e., the presence of an amount of air bubbles exceeding the allowable amount in the heat medium), the connection condition is not met, and the thermal management system 1 can disconnect the low-temperature flow path 130 and the battery flow path 170 using the five-way valve 180. The ECU 500 may operate the thermal management system 1 in a disconnection mode (FIG. 4). This allows the thermal management of the vehicle 10 to be performed separately for the low-temperature flow path 130 and the battery flow path 170. On the other hand, when the above-mentioned connection condition is met, the low-temperature flow path 130 is connected to the battery flow path 170 provided with a reserve tank. This allows the heat medium in the low-temperature flow path 130 to be bled (air bleed by the reserve tank). Such a thermal management system 1 makes it possible to reduce the amount of air bubbles in the heat medium and, as necessary, to flow the heat medium into a flow path (for example, circuit C11) separated from the reserve tank.

[0065] FIG. 7 is a flowchart showing the air bleeding control and the thermal management control in the first embodiment. "S" in the flowchart denotes a step. In this embodiment, the input device of the HMI 600A accepts a system start instruction and a system stop instruction from a user. When the input device receives a system start instruction while the vehicle system (including the ECU 500) is in a stopped state, the ECU 500 starts up and starts the process flow F1 shown in FIG. 7. Then, the process flow F1 is repeatedly executed while the ECU 500 is in an operating state. The calculation cycle may be about 50 ms. Thereafter, when the input device receives a system stop instruction, the ECU 500 executes a predetermined shutdown process and then enters a stopped state. This ends the process flow F1.

[0066] In the processing flow F1, an air bleeding execution flag and a time count value are used. The air bleeding execution flag is a parameter indicating whether or not the connection condition is met. When the air bleeding execution flag is ON, it means that the connection condition is met. While the connection condition is met, the thermal management system 1 operates in the air bleeding mode. In the air bleeding mode, the ECU 500 executes air bleeding control to maintain the thermal management system 1 in the connection mode (first or second connection mode). The time count value is a parameter indicating the elapsed time since the air bleeding control was started. These parameters are stored in the storage device 503.

[0067] When the ECU 500 is started, the above parameters are set to their initial values, and the connection condition is not met. The initial value of the air bleeding execution flag is "OFF," and the initial value of the time count value is "0." In this embodiment, when the ECU 500 determines that the heat medium contains more air bubbles than the allowable amount, the connection condition is switched from not met to met. Then, when the time count value exceeds a predetermined value, the connection condition is switched from met to not met. Hereinafter, determining whether the heat medium contains more air bubbles than the allowable amount is referred to as "air bubble determination."

[0068] 7, in S11, the ECU 500 acquires information (hereinafter referred to as "determination information") for determining whether or not there are bubbles in the heat medium (third heat medium) in the low-temperature flow path 130. In the following S12, the ECU 500 uses the acquired determination information to determine whether or not there are bubbles in the heat medium in the low-temperature flow path 130 in an amount exceeding the allowable amount. Hereinafter, the presence of bubbles in the heat medium in an amount exceeding the allowable amount will be referred to as "air bubbles present," and the amount of bubbles in the heat medium not exceeding the allowable amount will be referred to as "air bubbles not present."

[0069] In this embodiment, the judgment information includes at least one of the state (e.g., rotation speed) of the pump 131 shown in FIG. 8 and the trajectory length of the temperature detection value by the flow path sensor T2 (FIG. 2) shown in FIG. 9 (hereinafter referred to as the "sensor temperature trajectory length").

[0070] Fig. 8 is a diagram for explaining the first air bubble determination method. In Fig. 8, the horizontal axis represents the duty ratio (command duty) of the pump drive signal received by the pump 131 from the ECU 500, and the vertical axis represents the rotation speed of the pump 131. The pump 131 is driven to circulate the heat medium (third heat medium) through the low-temperature flow path 130 in any of the disconnected mode, the first connected mode, and the second connected mode. The pump 131 is driven by the pump drive signal from the ECU 500. The rotation speed of the pump 131 is detected by the pump sensor PS2 (Fig. 2).

[0071] Line L11 indicates the boundary value (first boundary value) between the high rotation abnormality region and the normal region with respect to the rotation speed (rpm) of the pump 131. The first boundary value tends to become higher as the command duty (%) becomes larger. Line L12 indicates the boundary value (second boundary value) between the normal region and the low rotation abnormality region with respect to the rotation speed (rpm) of the pump 131. The second boundary value tends to become higher as the command duty (%) becomes larger. The region where the rotation speed of the pump 131 is equal to or greater than the second boundary value (line L12) and equal to or less than the first boundary value (line L11) corresponds to the normal region. The region where the rotation speed of the pump 131 is higher than the first boundary value corresponds to the high rotation abnormality region. The region where the rotation speed of the pump 131 is lower than the second boundary value corresponds to the low rotation abnormality region. The map shown in FIG. 8 (including line L11 and line L12) is stored in the storage device 503.

[0072] In the first air bubble determination method, the ECU 500 acquires the command duty and rotation speed of the pump 131 in S11 of FIG. 7 . Subsequently, in S12, the ECU 500 determines whether the state of the pump 131 belongs to the high-speed abnormal region based on the information acquired in S11 and the line L11 in FIG. 8 . The ECU 500 determines that "air bubbles are present" if the state of the pump 131 belongs to the high-speed abnormal region, and determines that "air bubbles are not present" if the state of the pump 131 belongs to the normal region or the low-speed abnormal region. The fact that the state of the pump 131 belongs to the high-speed abnormal region means that the pump 131 is overspeeding. When air pockets in the heat medium (e.g., water) hit the blades of the pump 131, the resistance of the heat medium disappears, making the pump 131 prone to overspeeding. If the state of the pump 131 belongs to the high-speed abnormal region, it is considered that the pump 131 temporarily overspeeds due to an amount of air bubbles that exceeds the allowable amount and that have entered the heat medium.

[0073] The ECU 500 may determine whether the state of the pump 131 belongs to the low rotation abnormality region based on the line L12. If the state of the pump 131 belongs to the low rotation abnormality region, the ECU 500 may light or sound an alarm related to the pump 131. However, the determination of the low rotation abnormality of the pump 131 and the line L12 are not essential.

[0074] 9 is a diagram for explaining the second air bubble determination method. In Fig. 9, line L20 shows the transition of the temperature detection value (the detection value of the temperature of the heat medium in the low-temperature flow path 130) by the flow path sensor T2. In addition, lines D11 and D12 also show the transition of the temperature detection value by the flow path sensor T2. The flow path sensor T2 (Fig. 2) includes a temperature sensor (for example, a water temperature sensor) that detects the temperature of the heat medium in the low-temperature flow path 130.

[0075] Lines D11 and D21 respectively show the detected temperature value and the sensor temperature trajectory length when there are no more bubbles than the allowable amount in the heat medium in the low-temperature flow path 130. Lines D12 and D22 show the detected temperature value and the sensor temperature trajectory length when there are more bubbles than the allowable amount in the heat medium in the low-temperature flow path 130.

[0076] The ECU 500 accumulates the trajectory (amount of change in value) of the temperature detection value by the flow path sensor T2 for each unit period of length dT (for example, period t1 to t2, period t2 to t3, ...) to obtain the sensor temperature trajectory length. The greater the amount of change in the temperature detection value of the heat medium per unit period, the longer the sensor temperature trajectory length. The ECU 500 resets the sensor temperature trajectory length every time a unit period elapses and starts accumulating the sensor temperature trajectory length again from the initial value (0).

[0077] In the second air bubble determination method, the ECU 500 acquires (updates) the sensor temperature trajectory length in S11 of FIG. 7, and subsequently determines in S12 whether the sensor temperature trajectory length acquired in S11 is equal to or greater than a predetermined value (hereinafter referred to as "Th10"). The ECU 500 determines that "air bubbles are present" when the sensor temperature trajectory length is equal to or greater than Th10 (see line D22), and determines that "air bubbles are not present" when the sensor temperature trajectory length is less than Th10 (see line D21). When air bubbles (e.g., many small air bubbles) are present in the heat medium, the temperature sensor (flow path sensor T2) temporarily detects the gas temperature, making the temperature detection value more susceptible to the temperature of surrounding components. The presence of air bubbles makes it difficult for the heat medium to be transferred to the temperature sensor. When a large number of air bubbles exist in the heat medium in the low-temperature flow path 130, the temperature detection value by the flow path sensor T2 fluctuates drastically. This increases the sensor temperature trajectory length. When the sensor temperature trajectory length is Th10 or more, it is considered that the temperature sensor (flow path sensor T2) temporarily detected the temperature of the surrounding member due to an amount of air bubbles exceeding the allowable amount mixed into the heat medium.

[0078] The ECU 500 may combine the first air bubble determination method and the second air bubble determination method. For example, the ECU 500 may determine that "air bubbles are present" when either of the following phenomena is detected: the state of the pump 131 is in the high rotation abnormality region (first phenomenon) or the sensor temperature trajectory length is equal to or greater than Th10 (second phenomenon); and may determine that "air bubbles are not present" when neither of these phenomena is detected. The ECU 500 may also perform air bubble determination using other methods. The ECU 500 may use a trained model generated by machine learning using AI (artificial intelligence). For example, the air bubble determination may be performed using a trained model that is trained to output a result of air bubble determination when at least one of first input data indicating the state of the pump 131 (e.g., at least one of the rotation speed, current, and temperature detected by the pump sensor PS2) and second input data indicating the state of the heat medium in the low-temperature flow path 130 (e.g., at least one of the temperature and flow rate of the heat medium detected by the flow path sensor T2) is input.

[0079] If it is determined in S12 that "air bubbles are not mixed in" when the connection condition is not met (NO in S12), the connection condition remains unmet and the process proceeds to S15. In S15, ECU 500 determines whether the time count value is greater than a predetermined time (hereinafter referred to as "Th1"). Th1 may be, for example, a time between 30 seconds and 1 minute. If the time count value remains at its initial value (0), NO is determined in S15 and the process proceeds to S17. In S17, ECU 500 determines whether the air bleeding execution flag is "ON". If the air bleeding execution flag remains at its initial value (OFF), NO is determined in S17 and the process proceeds to S50.

[0080] In S50, the ECU 500 executes predetermined thermal management control (hereinafter referred to as "normal thermal management control") in the vehicle 10. In the normal thermal management control, the five-way valve 180 (switching device) is permitted to disconnect the low-temperature flow path 130 and the battery flow path 170. Therefore, the ECU 500 can perform thermal management of the vehicle 10 in any mode (including the modes shown in FIGS. 4 to 6). The ECU 500 switches between connection and disconnection of the low-temperature flow path 130 and the battery flow path 170 depending on, for example, the state of the vehicle 10. The ECU 500 may switch between the disconnection mode, the first connection mode, and the second connection mode based on the output of each sensor mounted on the vehicle 10. The ECU 500 may select the mode so that each device (subject to thermal management) mounted on the vehicle 10 does not become excessively hot or cold.

[0081] After the process of S50 is executed, the process returns to the first step (S11). As long as the air bleeding execution flag and the time count value are maintained at their initial values ​​and it is determined in S12 that "no air bubbles have been mixed in," the normal heat management control (S50) is continuously executed.

[0082] When the connection condition is not satisfied and it is determined in S12 that "air bubbles are present" (YES in S12), the process proceeds to S13. In S13, the ECU 500 determines whether the air bleeding execution flag is "ON." If the air bleeding execution flag remains at its initial value (OFF), the result is NO in S13, and then in S14, the ECU 500 sets the air bleeding execution flag to "ON," after which the process proceeds to S15. By changing the air bleeding execution flag from "OFF" to "ON," the connection condition is switched from not being satisfied to being satisfied. At this time, the air bleeding control is not being executed, the time count value is "0," and the air bleeding execution flag is "ON." Therefore, the result is NO in S15 and YES in S17, and the process proceeds to S21.

[0083] In S21, the ECU 500 determines whether the temperature of the heat medium (third heat medium) in the low-temperature flow path 130 is lower than a predetermined temperature (hereinafter referred to as "Th2"). The ECU 500 may acquire the temperature of the heat medium in the low-temperature flow path 130 based on the output of the flow path sensor T2 (FIG. 2). If the temperature of the heat medium in the low-temperature flow path 130 is lower than Th2 (YES in S21), the ECU 500 connects the low-temperature flow path 130 and the cooling path (flow path 170a) of the battery flow path 170 using the five-way valve 180 in the subsequent S51, and causes the third heat medium to flow through the low-temperature flow path 130 and the flow path 170a. More specifically, the ECU 500 controls the five-way valve 180 so that the thermal management system 1 operates in the first connection mode shown in FIG. 5. As a result, the cooling of the battery 171 is promoted and air is bled from the third heat medium. On the other hand, if the temperature of the heat medium in the low-temperature flow path 130 is equal to or higher than Th2 (NO in S21), the ECU 500 subsequently connects the low-temperature flow path 130 and the bypass path (flow path 170b) of the battery flow path 170 using the five-way valve 180 in S52, and causes the third heat medium to flow through the low-temperature flow path 130 and flow path 170b. More specifically, the ECU 500 controls the five-way valve 180 so that the thermal management system 1 operates in the second connection mode shown in FIG. 6. As a result, air is bled from the third heat medium while suppressing a temperature rise in the battery 171. The processes of S21, S51, and S52 above correspond to air bleed control.

[0084] As described above, in both S51 and S52, the five-way valve 180 connects the low-temperature flow path 130 and the battery flow path 170. In this way, when the connection condition is met, the five-way valve 180 (switching device) is prohibited from disconnecting the low-temperature flow path 130 and the battery flow path 170. When either of the processes of S51 and S52 is executed, the process proceeds to S22. In S22, the ECU 500 updates the time count value by counting time (for example, incrementing the time count value according to the elapsed time). The obtained time count value indicates the elapsed time since the connection condition was met, and corresponds to the execution time (integrated value) of the air bleeding control. When the time count value is updated (S22), the process returns to the first step (S11).

[0085] While the connection condition is satisfied, NO is determined in S15 and YES is determined in S17. Therefore, the air bleeding control (S21, S51, S52) is continuously executed. While the connection condition is satisfied, the ECU 500 determines in S15 whether or not air bleeding from the third heat medium has been completed. Then, when Th1 has elapsed since the connection condition was satisfied, the time count value reaches Th1. As a result, it is determined that air bleeding from the third heat medium has been completed (YES in S15), and the process proceeds to S16.

[0086] In S16, the ECU 500 resets the air bleeding execution flag and the time count value to their initial values. As a result, the air bleeding execution flag is changed from "ON" to "OFF," and the connection condition is changed from established to not established. Thereafter, the process proceeds to S17, where a NO determination is made in S17, and the process proceeds to S50. As a result, the air bleeding control (S21, S51, S52) is no longer executed. The thermal management system 1 may be maintained in the disconnection mode by the normal thermal management control (S50) until a predetermined period has elapsed since the air bleeding of the third heat medium was completed.

[0087] As described above, the ECU 500 (control device) is configured to be able to execute thermal management control of the vehicle 10 using a connection mode in which the first flow path and the second flow path are connected and a disconnection mode in which the first flow path and the second flow path are disconnected. While the connection condition is not satisfied, the ECU 500 executes thermal management control using the connection mode and the disconnection mode. Then, when the ECU 500 detects that an amount of air bubbles exceeding a permissible amount is present in the heat medium (third heat medium), the connection condition is switched from not being satisfied to being satisfied, and air bleeding control is executed to maintain the thermal management system 1 in the connection mode. While the connection condition is satisfied, the ECU 500 executes air bleeding control. Then, when a predetermined time (Th1) has elapsed since the connection condition was satisfied, the connection condition is switched from being satisfied to not being satisfied, and the ECU 500 switches from air bleeding control to thermal management control. This thermal management system 1 makes it possible to reduce the amount of air bubbles in the heat medium while allowing the heat medium to flow through a flow path disconnected from the reserve tank as necessary.

[0088] In the above embodiment, when a predetermined time has elapsed since the connection condition was satisfied, it is determined that the air bleeding from the heat medium has been completed, and the connection condition is switched from satisfied to not satisfied. Continuing to execute the air bleeding control for the predetermined time (Th1) makes it easier to perform sufficient air bleeding. However, any method can be used to determine whether the air bleeding from the heat medium has been completed. For example, the ECU 500 may execute a process flow F1A shown in FIG. 10 instead of the process flow F1 shown in FIG. 7.

[0089] FIG. 10 is a flowchart showing a modification of the process flow F1 shown in FIG. 7. The process flow F1A shown in FIG. 10 is the same as the process flow F1 (FIG. 7) except for the addition of S18. Referring to FIG. 10, in this modification, if it is determined in S12 that "air bubbles are not mixed in," the process proceeds to S18. In S18, the ECU 500 resets the air bleeding execution flag and the time count value to their initial values. During the period in which the connection condition is satisfied, the determination in S12 corresponds to determining whether or not air bleeding from the third heat medium is completed. More specifically, during the period in which the connection condition is satisfied, the ECU 500 determines whether or not air bleeding from the third heat medium is completed based on whether or not the amount of air bubbles in the heat medium is equal to or less than the allowable amount in S12. Then, when it is determined in S12 that "air bubbles are not mixed in" (NO in S12), it is determined that air bleeding from the third heat medium is completed, and the process proceeds to S18. Then, by the process of S18, the air bleeding execution flag is changed from "ON" to "OFF", and the connection condition is changed from satisfied to not satisfied, thereby switching from the air bleeding control (S21, S51, S52) to the heat management control (S50).

[0090] In the above-described embodiment, Th1 is set according to the time required to complete the air bleeding. However, the present invention is not limited to this, and Th1 may change according to the temperature of the battery 171 (a heating element provided in the second flow path). FIG. 11 is a diagram for explaining a modified example of the method for setting Th1 (the threshold value used in determining the completion of air bleeding). Referring to FIG. 11, the ECU 500 may set Th1 using, for example, a map indicated by line L30, so that Th1 decreases as the temperature of the battery 171 increases. In line L30, the rate of change indicated by the slope of the graph (the rate of change in Th1 relative to the change in the temperature of the battery 171) is constant. However, the present invention is not limited to this, and the rate of change may decrease or increase as the temperature of the battery 171 increases, as indicated by line L31 or line L32. Alternatively, Th1 may change in a stepwise manner according to the temperature of the battery 171, as indicated by line L33. In the process flow F1 (FIG. 7) or process flow F1A (FIG. 10) employing the thus set Th1, when a predetermined time (Th1) has elapsed since the connection condition was satisfied, the connection condition is switched from satisfied to not satisfied (S15 and S16). According to the map (lines L30 to L33), the higher the temperature of the battery 171, the shorter the predetermined time (Th1). This control makes it easier to simultaneously cool the heating element (battery 171) provided in the second flow path and bleed air from the heat medium in the first flow path (low-temperature flow path 130). Note that a flow rate may be employed instead of time. The ECU 500 may integrate the flow rate of the third heat medium (for example, the flow rate detected by the flow path sensor T2) instead of time in S22, and compare the integrated value of the flow rate with the predetermined value (Th1) in S15.

[0091] It is not essential that the ECU 500 always executes the process flow F1 or F1A while it is operating. The ECU 500 may execute the process flow F1 or F1A only in a predetermined situation (for example, when the temperature of the battery 171 is equal to or lower than a predetermined temperature). Furthermore, the ECU 500 may execute the process flow F1 or F1A while the vehicle 10 is traveling, and may execute air bleeding control using a process flow (different algorithm) not shown while the vehicle 10 is stopped or externally charged.

[0092] [Second embodiment] The second embodiment will be described below, focusing on the differences from the first embodiment.

[0093] FIG. 12 is a diagram illustrating a configuration of a thermal management system according to a second embodiment. Referring to FIG. 12, the thermal management system 1A includes a thermal management circuit 100A and an ECU 500A instead of the thermal management circuit 100 and the ECU 500 (FIG. 1). The thermal management circuit 100A includes a battery path 170X instead of the battery path 170 (FIG. 1). The battery path 170X basically has the same configuration as the battery path 170 (FIG. 1), but does not include a bypass path (path 170b). The thermal management circuit 100A also includes a switching valve 180A instead of the five-way valve 180 (FIG. 1). The five-way valve shown in FIG. 1 can be used as the switching valve 180A. However, in the switching valve 180A, the bypass path (path 170b) is not connected to port P4. Therefore, the switching valve 180A essentially functions as a four-way valve.

[0094] The thermal management system 1A can operate in a decoupled mode and a coupled mode, which are described below. FIG. 13 is a diagram illustrating the disconnection mode of the thermal management system 1A. Referring to FIG. 13, in this disconnection mode, in the switching valve 180A, the port P1 and the port P2 are connected, and the port P3 and the port P5 are connected. This forms circuits C31 and C32 that are separated from each other. These circuits C31 and C32 are formed in the same manner as the circuits C11 and C12 shown in FIG. 4, respectively. In the disconnection mode, the pumps 131 and 161 are driven, and the pump 131 circulates the heat medium through the circuit C31, and the pump 161 circulates the heat medium through the circuit C32. In the disconnection mode, the circuit C31 (including the low-temperature flow path 130) is disconnected from the reserve tank.

[0095] FIG. 14 is a diagram for explaining the connection mode of the thermal management system 1A. Referring to FIG. 14, in this connection mode, in the switching valve 180A, the port P1 and the port P5 are connected, and the port P2 and the port P3 are connected. As a result, a circuit C40 is formed similarly to the circuit C21 shown in FIG. 5. In the connection mode, the pumps 131 and 161 are activated and circulate the heat medium through the circuit C40. However, this is not limited thereto, and the ECU 500A may stop the pump 161 in the connection mode. In the connection mode, the low-temperature flow path 130 is connected to the battery flow path 170 in which the reserve tank 162 is provided, thereby bleeding the heat medium (third heat medium) in the low-temperature flow path 130.

[0096] The switching valve 180A is not limited to a five-way valve, but may be any other multi-way valve (for example, a four-way valve, a six-way valve, a seven-way valve, an eight-way valve, a nine-way valve, or a ten-way valve).

[0097] Fig. 15 is a flowchart showing air bleeding execution control in the second embodiment. ECU 500A has basically the same configuration as ECU 500 (Fig. 1), but executes process flow F2 shown in Fig. 15 instead of process flow F1 (Fig. 7). Process flow F2 shown in Fig. 15 is the same as process flow F1, except that S53 and S50A are adopted instead of S21 and S50 to S52 (Fig. 7).

[0098] In process flow F2, if the connection condition is met, a YES determination is made in S17, and air bleeding control is executed in S53. In S53, the ECU 500A connects the low-temperature flow path 130 and the flow path 170a using the switching valve 180A, and causes the third heat medium to flow through the low-temperature flow path 130 and the flow path 170a. More specifically, the ECU 500A controls the switching valve 180A so that the thermal management system 1A operates in the connection mode shown in FIG. 14. This executes air bleeding from the third heat medium. Thereafter, the process proceeds to S22.

[0099] On the other hand, if the connection condition is not met, a NO determination is made in S17, and thermal management control is executed in S50A. The thermal management control in S50A is basically the same as the normal thermal management control in S50 of FIG. 7. However, in S50A, the modes shown in FIGS. 13 and 14 are adopted instead of the modes shown in FIGS. 4 to 6. In S50A, the switching valve 180A (switching device) is permitted to separate the low-temperature flow path 130 and the battery flow path 170. The ECU 500A may switch between a disconnection mode (FIG. 13) and a connection mode (FIG. 14) depending on the state of the vehicle in which the thermal management system 1A is installed.

[0100] The thermal management system 1A according to the second embodiment described above also makes it possible to reduce the amount of bubbles in the heat medium and to cause the heat medium to flow in a flow path separated from the reserve tank as needed.

[0101] ECU 500A may be configured to execute a process flow F2A shown in FIG. 16 instead of the process flow F2 (FIG. 15). FIG. 16 is a flowchart showing a modification of the process flow shown in FIG. 15. The process flow F2A shown in FIG. 16 is the same as the process flow F2 (FIG. 15) except that S18 is added. S18 of the process flow F2A is the same as S18 of the process flow F1A (FIG. 10) described above.

[0102] In each of process flows F2 and F2A, Th1 may be a fixed value or may be variable. ECU 500A may set Th1 using, for example, the map shown in Fig. 11 (one of lines L30 to L33) so that Th1 decreases as the temperature of battery 171 increases. Also, a flow rate may be used instead of time (time count value).

[0103] It is not essential that the ECU 500A always executes the process flow F2 or F2A while it is operating. The ECU 500A may execute the process flow F2 or F2A only in a predetermined situation (for example, when the temperature of the battery 171 is equal to or lower than a predetermined temperature). Furthermore, the ECU 500A may execute the process flow F2 or F2A while the vehicle equipped with the thermal management system 1A is running, and may execute air bleeding control using a process flow (different algorithm) not shown while the vehicle is stopped or externally charged.

[0104] [Other embodiments] The configuration of the thermal management system is not limited to that shown in Fig. 1 or Fig. 12. Below, modified examples of the configuration of the thermal management system will be described.

[0105] <First Modification of the Thermal Management System Configuration> Fig. 17 is a diagram showing a first modified example of the configuration of the thermal management system shown in Fig. 1. The thermal management system 2 shown in Fig. 17 includes a thermal management circuit 200 and an ECU 520. The thermal management circuit 200 includes a condenser 250, a refrigeration cycle flow path 240 connected to the condenser 250, and an eight-way valve 280. The eight-way valve 280 includes eight ports P11 to P18. The thermal management circuit 200 further includes a chiller circuit 210, a radiator circuit 230, a drive unit circuit 260, and a battery circuit 270, which are connected to the eight-way valve 280. The thermal management circuit 200 is controlled by the ECU 520.

[0106] The chiller circuit 210 includes a flow path 210a. The flow path 210a connects ports P13 and P15 of the eight-way valve 280. A pump 211 and a chiller 220 are provided in the flow path 210a. The pump 211 is, for example, a water pump. The chiller 220 is connected to (shared with) both the chiller circuit 210 and the refrigeration cycle flow path 240. The chiller 220 exchanges heat between the heat medium circulating through the chiller circuit 210 and the heat medium circulating through the refrigeration cycle flow path 240. The radiator circuit 230 includes a flow path 230a. The flow path 230a connects ports P16 and P17 of the eight-way valve 280. A radiator 231 is provided in the flow path 230a. The radiator 231 is disposed downstream of a grille shutter (not shown) and exchanges heat between the outside air of the vehicle and the heat medium.

[0107] The refrigeration cycle flow path 240 is provided with a compressor 241, a solenoid valve 242, solenoid valves 244A, 244B, 245, and 246, an evaporator 247, a check valve 248, and an accumulator 249. The condenser 250 includes a water-cooled condenser 251 and an air-cooled condenser 252. The water-cooled condenser 251 is connected to both the refrigeration cycle flow path 240 and the radiator circuit 230.

[0108] The compressor 241 compresses the gas-phase refrigerant circulating through the refrigeration cycle flow path 240 in accordance with a control command from the ECU 520. The solenoid valve 242 is connected in parallel to the compressor 241 and adjusts the amount of gas-phase refrigerant flowing into the compressor 241 in accordance with a control command from the ECU 520. The solenoid valves 244A and 244B switch whether the gas-phase refrigerant discharged from the compressor 241 flows into the water-cooled condenser 251 or the air-cooled condenser 252 in accordance with a control command from the ECU 520. The water-cooled condenser 251 exchanges heat between the gas-phase refrigerant discharged from the compressor 241 and the heat medium flowing through the radiator circuit 230. The air-cooled condenser 252 exchanges heat with the air introduced into the vehicle cabin to produce warm air. The solenoid valve 245 limits the flow of liquid-phase refrigerant into the evaporator 247 in accordance with a control command from the ECU 520. Solenoid valve 246 limits the inflow of liquid-phase refrigerant into chiller 220 in accordance with a control command from ECU 520. Solenoid valves 245 and 246 have the function of expanding the liquid-phase refrigerant. Accumulator 249 removes liquid-phase refrigerant from the refrigerant in a gas-liquid mixed state, and prevents the liquid-phase refrigerant from being drawn into compressor 241 when the refrigerant is not completely vaporized by evaporator 247.

[0109] The drive unit circuit 260 includes a flow path 260a. The flow path 260a connects ports P12 and P18 of the eight-way valve 280. The flow path 260a is provided with a pump 261, an SPU 262, a PCU 263, an oil cooler 264, a reserve tank 265, and a heat medium temperature sensor 266. The reserve tank 265 maintains the pressure and amount of the heat medium in the drive unit circuit 260 by storing a portion of the heat medium in the drive unit circuit 260 (the heat medium that overflows due to a pressure increase). The heat medium temperature sensor 266 detects the temperature of the heat medium in the flow path 260a.

[0110] Pump 261 is, for example, a water pump. SPU 262 controls the charging and discharging of battery 272 in accordance with control commands from ECU 520. PCU 263 converts DC power supplied from battery 272 into AC power in accordance with control commands from ECU 520 and supplies the AC power to a motor (not shown) built into the transaxle. Oil cooler 264 cools the transaxle by heat exchange between a heat medium circulating through drive unit circuit 260 and lubricating oil for the motor. Heat generated by supplying power to the stator without rotating the rotor of the motor may be transferred to the heat medium circulating through drive unit circuit 260. SPU 262, PCU 263, and oil cooler 264 are cooled by the heat medium circulating through drive unit circuit 260.

[0111] The battery circuit 270 includes a flow path 270a. The flow path 270a is a flow path that connects ports P11 and P14 of the eight-way valve 280. No reserve tank is provided in the flow path 270a. The flow path 270a is provided with an ADAS (Advanced Driver-Assistance Systems) 271, a battery 272, and a temperature sensor 273. The battery circuit 270 may further include an autonomous driving system (ADS) in addition to the ADAS 271. The battery 272 may supply power for driving to a motor built into the transaxle. The temperature sensor 273 detects the temperature of the battery 272.

[0112] The eight-way valve 280 switches the path through which the heat medium flows in accordance with a control command from the ECU 520. The thermal management system 2 can operate in a disconnected mode, a first connected mode, a second connected mode, and a third connected mode, which will be described below.

[0113] FIG. 18 is a diagram illustrating the disconnection mode of the thermal management system 2. Referring to FIG. 18, in this disconnection mode, the eight-way valve 280 connects ports P11 and P15, ports P12 and P16, ports P13 and P14, and ports P17 and P18. This forms circuits C51 and C52 that are disconnected from each other. Circuit C51 is a fluid circuit that continuously connects port P11, flow path 270a, port P14, port P13, flow path 210a, and port P15. In the disconnection mode, the pump 211 is driven to circulate the heat medium through circuit C51. As a result, the heat medium that flows from flow path 210a to port P15 is output from port P11 to flow path 270a and flows through flow path 270a into port P14. Furthermore, the heat medium that flows into port P14 is output from port P13 to flow path 210a. Furthermore, circuit C52 is a fluid circuit in which port P16, flow path 230a, port P17, port P18, flow path 260a, and port P12 are continuously connected. In the disconnection mode, pump 261 is also driven, and pump 261 circulates the heat medium through circuit C52. As a result, the heat medium that flows from flow path 260a to port P12 is output from port P16 to flow path 230a, passes through flow path 230a, and flows into port P17. Furthermore, the heat medium that flows into port P17 is output from port P18 to flow path 260a. In the disconnection mode, circuit C51 (including flow path 270a) is disconnected from the reserve tank. Therefore, the heat medium in flow path 270a is not bled.

[0114] FIG. 19 is a diagram illustrating the first connection mode of the thermal management system 2. Referring to FIG. 19, in this first connection mode, the eight-way valve 280 connects ports P11 and P12, ports P13 and P17, ports P14 and P18, and ports P15 and P16. This forms circuits C61 and C62, which are separated from each other. Circuit C61 is a fluid circuit that continuously connects port P11, flow path 270a, port P14, port P18, flow path 260a, and port P12. In the first connection mode, the pump 261 is driven to circulate the heat medium through circuit C61. As a result, the heat medium that flows from flow path 260a to port P12 is output from port P11 to flow path 270a and flows through flow path 270a into port P14. Furthermore, the heat medium that flows into port P14 is output from port P18 to flow path 260a. Furthermore, circuit C62 is a fluid circuit in which port P16, flow path 230a, port P17, port P13, flow path 210a, and port P15 are continuously connected. In the first connection mode, pump 211 is also driven to circulate the heat medium through circuit C62. As a result, the heat medium that flows from flow path 210a to port P15 is output from port P16 to flow path 230a, passes through flow path 230a, and flows into port P17. Furthermore, the heat medium that flows into port P17 is output from port P13 to flow path 210a. In the first connection mode, eight-way valve 280 connects flow path 270a and flow path 260a. By connecting flow path 270a to flow path 260a, in which reserve tank 265 is provided, air is bled from the heat medium in flow path 270a.

[0115] FIG. 20 is a diagram illustrating the second connection mode of the thermal management system 2. Referring to FIG. 20, in this second connection mode, the eight-way valve 280 connects ports P11 and P15, ports P12 and P16, ports P13 and P17, and ports P14 and P18. This forms a circuit C71. The circuit C71 is a fluid circuit in which port P11, flow path 270a, port P14, port P18, flow path 260a, port P12, port P16, flow path 230a, port P17, port P13, flow path 210a, and port P15 are continuously connected. In the second connection mode, the pumps 211 and 261 are activated to circulate the heat medium through the circuit C71. As a result, the heat medium that has flowed from flow path 210a into port P15 is output from port P11 to flow path 270a, passes through flow path 270a into port P14, and is output from port P18 to flow path 260a. Furthermore, the heat medium passes through flow path 260a and flows into port P12, is output from port P16 to flow path 230a, passes through flow path 230a and flows into port P17, and is output from port P13 to flow path 210a. In the second connection mode, flow path 270a and flow path 260a are connected by eight-way valve 280. By connecting flow path 270a to flow path 260a in which reserve tank 265 is provided, air is bled from the heat medium in flow path 270a. Note that ECU 520 may stop pump 261 in the second connection mode.

[0116] FIG. 21 is a diagram illustrating the third connection mode of the thermal management system 2. Referring to FIG. 21, in this third connection mode, in the eight-way valve 280, ports P11 and P15, ports P12 and P13, and ports P14 and P18 are connected to each other. Furthermore, ports P16 and P17 are not connected to any other port. This forms a circuit C72. The circuit C72 is a fluid circuit in which port P11, flow path 270a, port P14, port P18, flow path 260a, port P12, port P13, flow path 210a, and port P15 are continuously connected. In the third connection mode, pumps 211 and 261 are activated to circulate the heat medium through circuit C72. As a result, the heat medium that has flowed from flow path 210a into port P15 is output from port P11 to flow path 270a, passes through flow path 270a to flow port P14, and is output from port P18 to flow path 260a. Furthermore, the heat medium passes through flow path 260a to flow port P12, and is output from port P13 to flow path 210a. In the third connection mode, flow path 270a and flow path 260a are connected by eight-way valve 280. By connecting flow path 270a to flow path 260a in which reserve tank 265 is provided, air is bled from the heat medium in flow path 270a. Note that ECU 520 may stop pump 261 in the third connection mode.

[0117] The ECU 520 may execute the process flow F2 shown in FIG. 15 or the process flow F2A shown in FIG. 16. However, in this modification, the modes shown in FIGS. 18 to 21 are employed instead of the modes shown in FIGS. 13 and 14. If the connection condition is not met, the disconnection mode is permitted in S50A. In S50A, the ECU 520 may switch between the disconnection mode (FIG. 18), the first connection mode (FIG. 19), the second connection mode (FIG. 20), and the third connection mode (FIG. 21) depending on the state of the vehicle in which the thermal management system 2 is installed. If the connection condition is met, the connection mode is maintained and the disconnection mode is prohibited in S53. In S53, the ECU 520 controls the eight-way valve 280 so that the thermal management system 2 operates in one of the first to third connection modes. This causes the heat medium in the flow path 270a to be bled. At S53, ECU 520 may select one connection mode from the first to third connection modes so that the devices (subject to thermal management) mounted on the vehicle do not become excessively hot or cold. In this modification, eight-way valve 280, flow path 270a, flow path 260a, and ECU 520 correspond to examples of the "switching device," "first flow path," "second flow path," and "control device" according to the present disclosure, respectively.

[0118] In a configuration in which a bypass path that bypasses battery 272 is provided in thermal management circuit 200, ECU 520 may execute process flow F1 shown in FIG. 7 or process flow F1A shown in FIG. 10. For example, a bypass path may be added to battery circuit 270, and a port connected to the bypass path may be added to eight-way valve 280 (switching device). The switching device (eight-way valve 280 with the added port) may be configured so that a valve element rotates in accordance with an instruction from ECU 520 to selectively connect either port P14 connected to the path (cooling path) in which battery 272 is provided or a port connected to the bypass path. A bypass path and its port may be added to a component other than battery 272 (for example, radiator 231).

[0119] <Second Modification of the Thermal Management System Configuration> Fig. 22 is a diagram showing a second modified example of the configuration of the thermal management system shown in Fig. 1. The thermal management system 3 shown in Fig. 22 includes a thermal management circuit 300 and an ECU 530. The thermal management circuit 300 includes a heat medium circuit 310 and a refrigeration circuit 320. The heat medium circuit 310 and the refrigeration circuit 320 share a chiller 326.

[0120] The heat medium circuit 310 includes flow paths 311 to 315, 340, pumps 311c, 312b, and a five-way valve 330. The five-way valve 330 has ports P21 to P25. Each of the pumps 311c, 312b is, for example, a water pump. The flow path 340 connects the pumps 311c and 312b. The flow path 340 includes branch portions 341, 342, and 343.

[0121] The flow path 311 connects the port P22 of the five-way valve 330 and the pump 311c. The flow path 311 is provided with a battery 311b and a temperature sensor 311d. The temperature sensor 311d detects the temperature of the battery 311b. The flow path 312 connects the port P21 of the five-way valve 330 and the pump 312b. The flow path 312 is provided with a front inverter 312c, a front electric motor 312d, a DC-DC converter 312e, a rear inverter 312f, a rear electric motor 312g, an ADAS-ECU 312h, and a temperature sensor 312i. The temperature sensor 312i detects the temperature of the heat medium flowing through the flow path 312. Neither of the flow paths 311, 312 is provided with a reserve tank. The flow path 313 connects the port P25 of the five-way valve 330 and the branching portion 341. A radiator 313a and a reserve tank 313b are provided in flow path 313. Flow path 314 is a flow path that connects port P24 of five-way valve 330 and branch portion 342. A chiller 326 is provided in flow path 314. Flow path 315 is a flow path that connects port P23 of five-way valve 330 and branch portion 343.

[0122] The refrigeration circuit 320 includes a circulation flow path 350, a bypass flow path 351, and an internal heat exchanger 329. The circulation flow path 350 is a flow path through which a working medium (e.g., water) circulates. The circulation flow path 350 is provided with a compressor 321, a condenser 322, a first expansion valve 323, an interior evaporator 324, and a manifold 327. A receiver drier 328 is connected to the manifold 327. The bypass flow path 351 is connected to the circulation flow path 350 so as to bypass the interior evaporator 324. The bypass flow path 351 is provided with a second expansion valve 325 and a chiller 326. The internal heat exchanger 329 is connected to a portion of the circulation flow path 350 upstream of the first expansion valve 323 and a portion of the circulation flow path 350 downstream of the interior evaporator 324.

[0123] In the circulation flow path 350, the compressor 321 compresses the working medium. The condenser 322 condenses the working medium discharged from the compressor. The first expansion valve 323 expands the working medium flowing out from the condenser 322. The interior evaporator 324 exchanges heat between the working medium flowing out from the first expansion valve 323 and the air in the vehicle cabin. The chiller 326 exchanges heat between the heat medium flowing through the flow path 314 and the working medium flowing through the bypass flow path 351.

[0124] The five-way valve 330 may switch the flow path of the thermal management circuit 300 in accordance with a control command from the ECU 530, thereby operating the thermal management system 3 in any of a heating mode in which the battery 311b is heated, a cooling mode in which the battery 311b is cooled, a vehicle interior cooling mode, a vehicle interior heating mode, or a mode combining these modes. The thermal management system 3 may also operate in a disconnected mode, a first connected mode, a second connected mode, and a third connected mode, which will be described below.

[0125] The thermal management system 3 shown in FIG. 22 is operating in isolation mode. In isolation mode, port P24 of the five-way valve 330 is connected to ports P21 and P22. Ports P23 and P25 are not connected to any other ports. This forms circuits C81 and C82. Circuit C81 is a fluid circuit that connects port P24, flow path 314, flow path 340, pump 311c, flow path 311, and port P22. Circuit C82 is a fluid circuit that connects port P24, flow path 314, flow path 340, pump 312b, flow path 312, and port P21. In isolation mode, pumps 311c and 312b are driven, and these pumps circulate the heat medium through circuits C81 and C82. The heat medium that flows out from port P24 to flow path 314 branches at branch point 342 and flows through flow path 340 toward flow paths 311 and 312. The heat medium pressurized by pump 311c flows into port P22 through flow path 311. The heat medium pressurized by pump 312b flows into port P21 through flow path 312. In the disconnection mode, each of circuits C81 and C82 is disconnected from the reserve tank. Therefore, air is not bled from the heat medium in each of flow paths 311 and 312.

[0126] FIG. 23 is a diagram illustrating a first connection mode of the thermal management system 3. Referring to FIG. 23, in the first connection mode, port P25 is connected to each of ports P21 and P22 in the five-way valve 330. Ports P23 and P24 are not connected to any other port. This forms circuits C91 and C92. Circuit C91 is a fluid circuit in which port P25, flow path 313, flow path 340, pump 311c, flow path 311, and port P22 are connected in series. Circuit C92 is a fluid circuit in which port P25, flow path 313, flow path 340, pump 312b, flow path 312, and port P21 are connected in series. In the first connection mode, pumps 311c and 312b are driven, and these pumps circulate the heat medium through circuits C91 and C92. The heat medium flowing from port P25 to flow path 313 branches at branch point 341 and flows through flow path 340 toward flow paths 311 and 312. In the first connection mode, flow path 313 is connected to each of flow paths 311 and 312 by five-way valve 330. By connecting each of flow paths 311 and 312 to flow path 313, which is provided with reserve tank 313b, air is bled from the heat medium in each of flow paths 311 and 312.

[0127] FIG. 24 is a diagram illustrating the second connection mode of the thermal management system 3. Referring to FIG. 24, in the second connection mode, in the five-way valve 330, the port P21 is connected to each of the ports P24 and P25, and the port P22 is connected to each of the ports P24 and P25. Furthermore, the port P23 is not connected to any other port. Even in this second connection mode, the five-way valve 330 connects the flow path 313 to each of the flow paths 311 and 312. By connecting each of the flow paths 311 and 312 to the flow path 313 provided with the reserve tank 313b, air is bled from the heat medium in each of the flow paths 311 and 312. Furthermore, in the second connection mode, each of the flow paths 311 and 312 is also connected to the flow path 314.

[0128] FIG. 25 is a diagram illustrating the third connection mode of the thermal management system 3. Referring to FIG. 25, in the third connection mode, in the five-way valve 330, the port P21 is connected to each of the ports P23 to P25, and the port P22 is connected to each of the ports P23 to P25. In this third connection mode, the five-way valve 330 also connects the flow path 313 to each of the flow paths 311 and 312. By connecting each of the flow paths 311 and 312 to the flow path 313 provided with the reserve tank 313b, air is bled from the heat medium in each of the flow paths 311 and 312. In the third connection mode, the flow paths 311 and 312 are also connected to the flow paths 314 and 315.

[0129] The ECU 530 may execute the process flow F2 shown in FIG. 15 or the process flow F2A shown in FIG. 16. However, in this modification, the modes shown in FIGS. 22 to 25 are employed instead of the modes shown in FIGS. 13 and 14. If the connection condition is not met, the disconnection mode is permitted in S50A. In S50A, the ECU 530 may switch between the disconnection mode (FIG. 22), the first connection mode (FIG. 23), the second connection mode (FIG. 24), and the third connection mode (FIG. 25) depending on the state of the vehicle in which the thermal management system 3 is installed. If the connection condition is met, the connection mode is maintained and the disconnection mode is prohibited in S53. In S53, the ECU 530 controls the five-way valve 330 so that the thermal management system 3 operates in one of the first to third connection modes. This causes the heat medium to be bled from each of the flow paths 311 and 312. In S53, ECU 530 may select one connection mode from the first to third connection modes so that the devices (subject to thermal management) mounted on the vehicle do not become excessively hot or cold. In this modification, five-way valve 330, flow paths 311 and 312, flow path 313, and ECU 530 correspond to examples of the "switching device," "first flow path," "second flow path," and "control device" according to the present disclosure, respectively.

[0130] In a configuration in which a bypass path that bypasses battery 311b is provided in thermal management circuit 300, ECU 530 may execute process flow F1 shown in Fig. 7 or process flow F1A shown in Fig. 10. For example, port P23 may be changed from an output port to an input port, thereby changing flow path 315 to a bypass path.

[0131] Vehicles to which the thermal management system is applied are not limited to passenger cars, but may also be buses, trucks, or work vehicles (tractors, forklifts, etc.). The vehicle may be configured to be capable of unmanned driving by automatic driving or remote driving. The vehicle may also be an automated guided vehicle (AGV). The number of wheels is not limited to four, but may be three, five, or more. The vehicle may also be configured to be wirelessly rechargeable.

[0132] The various features of the thermal management system and the thermal management method described above (the features described in the embodiments and the modified examples) may be implemented in any combination. The thermal management system may be applied to devices other than vehicles.

[0133] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the description of the above embodiments, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0134] 1,1A,2,3 Thermal management system, 10 Vehicle, 100,100A,200,300 Thermal management circuit, 131,161,211,261,311c,312b Pump, 171,272,311b Battery, 162,265,313b Reserve tank, 180 Five-way valve, 180A Switching valve, 280 Eight-way valve, 330 Five-way valve, 500,500A,520,530 ECU.

Claims

1. a first flow path not provided with a reserve tank; a second flow path provided with a reserve tank; a switching device configured to be able to switch between connection and disconnection of the first flow path and the second flow path; a control device that controls the switching device, the control device is configured to circulate the heat medium through the first flow path and the second flow path connected by the switching device when a predetermined connection condition is met, the control device is configured to determine whether an amount of bubbles in the heat transfer medium exceeds an allowable amount; A thermal management system in which the connection condition is switched from not being satisfied to being satisfied when the control device determines that an allowable amount of air bubbles is present in the heat medium.

2. When the connection condition is satisfied, the switching device is prohibited from separating the first flow path and the second flow path, The thermal management system according to claim 1 , wherein when the connection condition is not met, the switching device is permitted to disconnect the first flow path from the second flow path.

3. the thermal management system further includes a pump that circulates the heat medium through the first flow path; the control device is configured to detect overspeed of the pump based on a state of the pump; The thermal management system of claim 1 , wherein the control device is configured to determine that an unacceptable amount of air bubbles is present in the heat transfer medium when overspeed of the pump is detected.

4. The thermal management system further includes a temperature sensor for detecting a temperature of the heat medium. The thermal management system according to claim 1 , wherein the control device is configured to determine whether or not an amount of bubbles exceeding an allowable amount is present in the heat medium based on whether or not a trajectory length of the value detected by the temperature sensor is equal to or greater than a predetermined value.

5. The control device determines whether or not air bleeding from the heat medium is completed during a period in which the connection condition is satisfied, The thermal management system according to claim 1 , wherein when it is determined that the air removal from the heat medium has been completed, the connection condition is switched from being satisfied to being not satisfied.

6. The thermal management system according to claim 5 , wherein the control device determines that the air bleeding from the heat medium is completed when a predetermined time has elapsed since the connection condition was met.

7. The thermal management system according to claim 5 , wherein the control device determines that the deaeration of the heat medium is completed when it is determined that no air bubbles exceeding an allowable amount are present in the heat medium.

8. When a predetermined time has elapsed since the connection condition was met, the connection condition is switched from met to not met, The thermal management system according to claim 1 , wherein the predetermined time period is shorter as the temperature of the heating element provided in the second flow path is higher.

9. The thermal management system of claim 1 , wherein the switching device comprises at least one of a four-way valve, a five-way valve, a six-way valve, a seven-way valve, an eight-way valve, a nine-way valve, and a ten-way valve.

10. A vehicle comprising a thermal management system according to any one of claims 1 to 9.

11. the first flow path is configured to be able to cool a first heating element mounted on the vehicle by the heat medium, the second flow path includes a cooling path that can cool a second heating element mounted on the vehicle by the heat medium, and a bypass path that bypasses the second heating element, The vehicle according to claim 10 , wherein the switching device is configured to be able to switch between the cooling path and the bypass path.

12. the second heating element includes a power storage device, the first heating element includes a component that receives a supply of power from the power storage device, The control device When the connection condition is satisfied and the temperature of the heat medium in the first flow path is lower than a predetermined temperature, the switching device connects the first flow path to the cooling path of the second flow path, and circulates the heat medium through the first flow path and the cooling path; When the connection condition is satisfied and the temperature of the heat medium in the first flow path exceeds the predetermined temperature, the switching device connects the first flow path to the bypass path of the second flow path, and causes the heat medium to circulate through the first flow path and the bypass path. The vehicle of claim 11 configured as follows:

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