THERMAL MANAGEMENT SYSTEM

A thermal management system includes: an electrical storage device configured to exchange heat with a first flow path; a drive device configured to exchange heat with a second flow path; a radiator provided on a third flow path; a chiller device provided on a fourth flow path; and a switching device. In the thermal management system, during heating control for the electrical storage device, the switching device are controlled so that a connection flow path connecting the first flow path and the fourth flow path is formed and that the connection flow path, the second flow path, and the third flow path are disconnected from and independent of each other.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No. 2023-036606 filed on Mar. 9, 2023, incorporated herein by reference in its entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to thermal management systems.

2. Description of Related Art

Japanese Unexamined Patent Application Publication No. 2010-272395 (JP 2010-272395 A) discloses an electrified vehicle. The electrified vehicle includes an electrical storage device (battery), an inverter, a motor, and a control device. The electrical storage device is connected to the inverter. The inverter is connected to the motor. The control device controls the current of the electrical storage device by controlling switching of the inverter. The control device thus controls heat that is generated due to power loss in the internal resistance of the electrical storage device. As a result, the control device can perform heating control for increasing the temperature of the electrical storage device using the current of the electrical storage device (self-heating of the electrical storage device).

SUMMARY

In electrical apparatuses such as electrified vehicles, it is sometimes important to effectively use heat from a drive device including an inverter and a motor. Efficient self-heating of an electrical storage device is also desired. That is, it is desired to allow efficient self-heating of the electrical storage device while effectively using heat generated by the drive device.

The present disclosure provides a thermal management system that allows efficient self-heating of an electrical storage device while effectively using heat generated by a drive device.

A thermal management system according to one aspect of the present disclosure is a thermal management system mounted on an electrical apparatus. The thermal management system includes: a first flow path, a second flow path, a third flow path, and a fourth flow path, each configured to allow a heat medium to flow through; an electrical storage device configured to exchange heat with the heat medium in the first flow path; a drive device configured to exchange heat with the heat medium in the second flow path and to supply a driving force to the electrical apparatus; a radiator provided on the third flow path; a chiller device provided on the fourth flow path; and a switching device configured to switch a connection state among the first flow path, the second flow path, the third flow path, and the fourth flow path. The switching device is configured to cause a heating circuit formed when heating the electrical storage device by causing a current to flow through the electrical storage device. The heating circuit is a flow path circuit in which a connection flow path connecting the first flow path and the fourth flow path is formed and the connection flow path, the second flow path, and the third flow path are disconnected from and independent of each other.

In the thermal management system according to the above aspect of the present disclosure, as described above, the connection flow path connecting the first flow path and the second flow path is formed and the connection flow path, the second flow path, and the third flow path are disconnected from and independent of each other when heating the electrical storage device. Therefore, heat from self-heating of the electrical storage device is less likely to escape to the drive device in the second flow path and the radiator in the third flow path. Moreover, heat generated by the drive device is less likely to escape to the electrical storage device in the first flow path and the radiator in the third flow path. It is therefore possible to allow efficient self-heating of the electrical storage device while effectively using the heat generated by the drive device.

In the thermal management system according to the above aspect, the electrical apparatus may be an electrified vehicle. The electrical storage device may be heated when a traction system of the electrified vehicle is activated. With this configuration, the temperature of the electrical storage device can be easily increased when the electrified vehicle starts to travel. As a result, the traveling performance of the electrified vehicle can be easily increased to a certain level or higher when the electrified vehicle starts to travel.

In the thermal management system according to the above aspect, the electrical storage device may be configured to be externally chargeable with charging power supplied from charging equipment external to the electrical apparatus. At start of being externally charged, the electrical storage device may be heated to increase a temperature of the electrical storage device to a predetermined temperature or higher. With this configuration, the temperature of the electrical storage device can be easily increased at the start of the external charging. As a result, the charging rate and charging efficiency can be easily increased to a certain level or higher at the start of the external charging. As used herein, “at the start of charging” refers to when the charging power begins to be supplied to the electrical storage device.

The thermal management system according to the above aspect may further include: a first temperature sensor configured to measure the temperature of the electrical storage device; a second temperature sensor configured to measure a temperature of the heat medium in the first flow path; and a pump configured to circulate the heat medium in the connection flow path. The pump may be stopped when a measured value from the first temperature sensor is higher than a measured value from the second temperature sensor during heating with the heating circuit formed. The pump may be driven when the measured value from the first temperature sensor is equal to or less than the measured value from the second temperature sensor during the heating with the heating circuit formed. With this configuration, when the measured value from the first temperature sensor is higher than the measured value from the second temperature sensor, the pump is stopped, so that the heat medium in the first flow path does not flow. Accordingly, heat of the electrical storage device is less likely to transfer to the heat medium in the first flow path. When the measured value from the first temperature sensor is equal to or less than the measured value from the second temperature sensor, the pump is driven, so that the heat medium in the first flow path flows. Accordingly, heat of the heat medium in the first flow path can be transferred to the electrical storage device.

In the thermal management system according to the above aspect, the electrical apparatus may be an electrified vehicle. The chiller device may be configured to exchange heat with an air conditioning circuit configured to adjust a cabin temperature of the electrified vehicle. When a heating request using the air conditioning circuit is made during the heating with the heating circuit formed, heat generated by the electrical storage device may be supplied to the air conditioning circuit via the chiller device. With this configuration, heat from self-heating of the electrical storage device can be easily used in the air conditioning circuit.

The thermal management system according to the above aspect may further include a control device. The control device may be configured to, when heating the electrical storage device by causing a current to flow through the electrical storage device, control the switching device to cause the heating circuit formed.

In the thermal management system according to the above aspect, the switching device may include a first five-way valve configured to connect or disconnect the first flow path, the second flow path, the third flow path, and the fourth flow path to or from each other, and a second five-way valve configured to connect or disconnect the first flow path, the second flow path, the third flow path, and the fourth flow path to or from each other.

In the thermal management system according to the above aspect, the switching device may include an eight-way valve configured to connect or disconnect the first flow path, the second flow path, the third flow path, and the fourth flow path to or from each other.

In the thermal management system according to the above aspect, the switching device may include a first six-way valve configured to connect or disconnect the first flow path, the second flow path, the third flow path, and the fourth flow path to or from each other, and a second six-way valve configured to connect or disconnect the first flow path, the second flow path, the third flow path, and the fourth flow path to or from each other.

According to the present disclosure, it is possible to allow efficient self-heating of the electrical storage device while effectively using heat generated by the drive device.

DETAILED DESCRIPTION OF EMBODIMENTS

A first embodiment of the present disclosure will be described in detail below with reference to the drawings. The same or corresponding parts are denoted by the same signs throughout the drawings, and description thereof will not be repeated.

Hereinafter, a configuration in which a thermal management system according to the present disclosure is mounted on an electrified vehicle1a(seeFIG.1) will be described as an example. The electrified vehicle1ais preferably a vehicle equipped with a traction battery173, and is, for example, a battery electric vehicle (BEV). The electrified vehicle1amay be a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), or a fuel cell electric vehicle (FCEV). However, the thermal management system according to the present disclosure is not limited to vehicle applications. The electrified vehicle1ais an example of the “electrical apparatus” of the present disclosure.

First Embodiment

Overall Configuration

FIG.2shows an example of the overall configuration of a thermal management system1according to the first embodiment of the present disclosure. The thermal management system1includes a thermal management circuit100, an electronic control unit (ECU)500, and a human machine interface (HMI)600.

The thermal management circuit100is configured to allow a heat medium to flow therethrough. The thermal management circuit100includes, for example, a high temperature circuit110, a radiator120, a low temperature circuit130, a condenser140, a refrigeration cycle150, a chiller160, a battery circuit170, a five-way valve180, and a five-way valve190. Each of the five-way valves180,190is an example of the “switching device” of the present disclosure. The chiller160is an example of the “chiller device” of the present disclosure.

The high temperature circuit110includes, for example, a water pump (W/P)111, an electric heater112, a three-way valve113, a heater core114, and a reservoir tank (R/T)115. The heater core114is an example of the “air conditioning circuit” of the present disclosure.

The radiator120is connected to (i.e., shared by) both the high temperature circuit110and the low temperature circuit130. The radiator120includes a high temperature (HT) radiator121and a low temperature (LT) radiator122(seeFIG.3). The low temperature radiator122exchanges heat between the heat medium flowing in the low temperature circuit130and outside air. The low temperature radiator122is an example of the “radiator” of the present disclosure.

The low temperature circuit130includes, for example, a water pump131, a smart power unit (SPU)132, a power control unit (PCU)133, an oil cooler (O/C)134, a buck-boost converter135, and a reservoir tank136. The PCU133and the oil cooler134are examples of the “drive device” of the present disclosure.

The condenser140is connected to both the high temperature circuit110and the refrigeration cycle150.

The refrigeration cycle150includes, for example, a compressor151, an expansion valve152, an evaporator153, an evaporative pressure regulator (EPR)154, and an expansion valve155.

The chiller160is connected to both the refrigeration cycle150and the battery circuit170. The chiller160exchanges heat between the heat medium flowing in the battery circuit170and the heat medium circulating in the refrigeration cycle150.

The battery circuit170includes, for example, a water pump171, an electric heater172, a battery173, a bypass path174, a battery temperature sensor175, and a heat medium temperature sensor176. The water pump171and the battery173are examples of the “pump” and the “electrical storage device” of the present disclosure, respectively. The battery temperature sensor175and the heat medium temperature sensor176are examples of the “first temperature sensor” and the “second temperature sensor” of the present disclosure, respectively.

Each of the five-way valves180,190is connected to the low temperature circuit130and the battery circuit170. The configuration of the thermal management circuit100will be described in detail with reference toFIG.3.

The ECU500controls the thermal management circuit100. The ECU500includes a processor501, a memory502, a storage503, and an interface504.

The processor501is, for example, a central processing unit (CPU) or a micro-processing unit (MPU). The memory502is, for example, a random access memory (RAM). The storage503is a rewritable nonvolatile memory such as a hard disk drive (HDD), a solid state drive (SSD), or a flash memory. The storage503stores system programs including an operating system (OS), and control programs including computer-readable codes that are necessary for control calculations. The processor501implements various processes by reading the system programs and the control programs, loading them into the memory502, and executing them. The interface504controls communication between the ECU500and components of the thermal management circuit100.

The ECU500generates control commands based on sensor values acquired from various sensor (e.g., battery temperature sensor175and heat medium temperature sensor176) included in the thermal management circuit100, user operations received by the HMI600, etc., and outputs the generated control commands to the thermal management circuit100. The ECU500may be divided into a plurality of ECUs, one for each function.

AlthoughFIG.2illustrates an example in which the ECU500includes one processor501, the ECU500may include a plurality of processors. The same applies to the memory502and the storage503.

As used herein, the “processor” is not limited to a processor in a narrow sense that performs processes by a stored program method, and may include hardwired circuitry such as an application-specific integrated circuit (ASIC) and a field-programmable gate array (FPGA). Therefore, the term “processor” may be read as processing circuitry that performs processes defined in advance by computer-readable codes and/or hardwired circuitry.

The HMI600is a display with a touch panel, an operation panel, a console, etc. The HMI600receives user operations for controlling the thermal management system1. The HMI600outputs signals indicating user operations to the ECU500.

Configuration of Thermal Management Circuit

FIG.3shows an example of the configuration of the thermal management circuit100according to the first embodiment. A heat medium (usually hot water) circulating in the high temperature circuit110flows through either or both of a first path and a second path. The first path is a path of “water pump111—condenser140—electric heater112—three-way valve113—heater core114—reservoir tank115—water pump111.” The second path is a path of “water pump111—condenser140—electric heater112—three-way valve113—high temperature radiator121—reservoir tank115—water pump111.”

The heat medium (coolant) circulating in the low temperature circuit130flows through a path of “water pump131—SPU132—PCU133—oil cooler134—buck-boost converter135—five-way valve180—low temperature radiator122—five-way valve190—reservoir tank136—water pump131.”

The water pump131circulates the heat medium in the low temperature circuit130according to a control command from the ECU500. The SPU132controls charge and discharge of the battery173according to a control command from the ECU500. The PCU133converts direct current (DC) power supplied from the battery173to alternating current (AC) power to supply the AC power to a motor (not shown) contained in a transaxle according to a control command from the ECU500. The oil cooler134circulates lubricating oil for the motor by using an electrical oil pump (EOP) (not shown). The oil cooler134cools the transaxle through heat exchange between the heat medium circulating in the low temperature circuit130and the lubricating oil for the motor. The SPU132, the PCU133, the oil cooler134, and the buck-boost converter135are cooled by the heat medium circulating in the low temperature circuit130. The reservoir tank136stores part of the heat medium flowing in the low temperature circuit130to maintain the pressure and amount of heat medium in the low temperature circuit130. Each of the five-way valves180,190switches the path of the heat medium in the low temperature circuit130and the battery circuit170according to a control command from the ECU500. The low temperature radiator122is disposed near the high temperature radiator121, and exchanges heat with the high temperature radiator121. Instead of the oil cooler134, the transaxle may be provided in the low temperature circuit130.

The heat medium (gas-phase refrigerant or liquid-phase refrigerant) circulating in the refrigeration cycle150flows through either or both of a first path and a second path. The first path is a path of “compressor151—condenser140—expansion valve152—evaporator153—EPR154—compressor151.” The second path is a path of “compressor151—condenser140—expansion valve155—chiller160—compressor151.”

The heat medium (coolant) circulating in the battery circuit170flows through either or both of a first path and a second path. The first path is a path of “water pump171—chiller160—five-way valve180—electric heater172—battery173—five-way valve190—water pump171.” The second path is a path of “water pump171—chiller160—five-way valve180—bypass path174—five-way valve190—water pump171.

The water pump171circulates the heat medium in the battery circuit170according to a control command from the ECU500. The chiller160cools the heat medium circulating in the battery circuit170through heat exchange between the heat medium circulating in the refrigeration cycle150and the heat medium circulating in the battery circuit170. The electric heater172heats the heat medium according to a control command from the ECU500. The battery173supplies traction power to the motor contained in the transaxle. The battery173may be heated with the electric heater172or may be cooled with the chiller160. The bypass path174is provided to allow the heat medium to bypass the electric heater172and the battery173. When the heat medium flows through the bypass path174, a change in temperature of the heat medium due to heat absorption and heat dissipation between the heat medium and the battery173can be reduced. The battery temperature sensor175detects the temperature of the battery173. The heat medium temperature sensor176detects the temperature of the heat medium flowing in the battery circuit170.

The five-way valve180is provided with five ports P1to P5. The port P1is an inlet port into which the heat medium flows from the chiller160. The port P2is an outlet port through which the heat medium flows toward the electric heater172and the battery173of the battery circuit170. The port P3is an inlet port into which the heat medium flows from the SPU132, the PCU133, the oil cooler134, and the buck-boost converter135of the low temperature circuit130. The port P4is an outlet port from which the heat medium flows toward the bypass path174of the battery circuit170. The port P5is an outlet port from which the heat medium flows toward the low temperature radiator122.

The five-way valve190is provided with five ports P11to P15. The port P11is an outlet port from which the heat medium flows toward the chiller160. The port P12is an inlet port into which the heat medium flows from the electric heater172and the battery173of the battery circuit170. The port P13is an outlet port from which the heat medium flows toward the SPU132, the PCU133, the oil cooler134, and the buck-boost converter135of the low temperature circuit130. The port P14is an inlet port into which the heat medium flows from the bypass path174of the battery circuit170. The port P15is an inlet port into which the heat medium flows from the low temperature radiator122.

As shown inFIG.4, the battery173is provided in a flow path170bof the battery circuit170. The battery173exchanges heat with the heat medium in the flow path170b.The flow path170bis in thermal contact with the battery173. The flow path170bis a flow path connecting the port P2of the five-way valve180and the port P12of the five-way valve190. The flow path170bis an example of the “first flow path” of the present disclosure.

The low temperature radiator122is provided in a flow path130aof the low temperature circuit130. The flow path130ais a flow path connecting the port P5of the five-way valve180and the port P15of the five-way valve190. The flow path130ais an example of the “third flow path” of the present disclosure.

The water pump131, the SPU132, the PCU133, the oil cooler134, the buck-boost converter135, and the reservoir tank136are provided in the flow path130bof the low temperature circuit130. The PCU133, the oil cooler134, etc. exchange heat with the heat medium in the flow path130b.The flow path130bis in thermal contact with the SPU132, the PCU133, the oil cooler134, and the buck-boost converter135. The flow path130bis a flow path connecting the port P3of the five-way valve180and the port P13of the five-way valve190. The flow path130bis an example of the “second flow path” of the present disclosure.

The chiller160is provided in a flow path170aof the battery circuit170. The flow path170ais a flow path connecting the port P1of the five-way valve180and the port P11of the five-way valve190. The flow path170ais an example of the “fourth flow path” of the present disclosure.

Communication Patterns

FIG.4is a conceptual diagram showing an overview of a predetermined communication pattern (hereinafter sometimes referred to as “battery heating communication pattern”) of the thermal management circuit100that is formed by controlling the five-way valve180and the five-way valve190. The battery heating communication pattern is an example of the “heating circuit” of the present disclosure.

Some electrified vehicles are not equipped with an engine. Therefore, there are cases where it is not possible to use engine waste heat to heat a component in an electrified vehicle that is to be heated. Accordingly, it is sometimes important to effectively use heat from a drive device including an inverter and a motor. Efficient self-heating of an electrical storage device is also desired. That is, it is desired to allow efficient self-heating of the electrical storage device while effectively using heat generated by the drive device.

In the first embodiment, the ECU500causes the battery heating communication pattern shown inFIG.4formed when heating the battery173. In the battery heating communication pattern, the five-way valve180forms a path communicating between the port P1and the port P2and a path communicating between the port P3and the port P4.

In the battery heating communication pattern, the five-way valve190forms a path communicating between the port P11and the port P12and a path communicating between the port P13and the port P14.

As a result, the bypass path174and the flow path130bare connected to form a first closed circuit10. The flow path170aand the flow path170bare also connected to form a second closed circuit20. The second closed circuit20is an example of the “connection flow path” of the present disclosure.

The first closed circuit10, the second closed circuit20, and the flow path130aare thus disconnected from and independent of each other. That is, the low temperature radiator122is independent without being connected to either the first closed circuit10or the second closed circuit20.

When the battery173is used in the battery heating communication pattern shown inFIG.4, heat from self-heating of the battery173is accumulated (stored) in the second closed circuit20. In this case, the chiller160is basically not operated. However, the chiller160may be operated if there is a heat request for air conditioning.

The PCU133and the transaxle (not shown) also generate heat during self-heating of the battery173. The heat generated by the PCU133and the transaxle is accumulated (stored) in the first closed circuit10.

As a result, it is possible to allow efficient self-heating of the battery173while effectively using heat generated by the drive device such as the PCU133.

Method for Controlling Thermal Management Circuit

A method for controlling the thermal management system1will be described with reference to the flowchart ofFIG.5. The flow shown inFIG.5is merely illustrative, and the control in the present disclosure is not limited to the example shown inFIG.5.

In step S1, driving of the electrified vehicle1ais started (traction system is activated). Specifically, a start button, not shown, of the electrified vehicle1ais pressed, so that the PCU133and the battery173are electrically connected (by a system main relay (SMR), not shown). By receiving a predetermined internal signal in the electrified vehicle1a,the ECU500detects that driving of the electrified vehicle1ahas been started.

In step S2, the ECU500determines whether the temperature of the battery173detected by the battery temperature sensor175is lower than 10° C. When the temperature of the battery173is lower than 10° C. (Yes in S2), the process proceeds to step S3. When the temperature of the battery173is equal to or higher than 10° C. (No in S2), the process ends. The threshold in step S2may be a value other than 10° C.

In step S3, the ECU500controls the five-way valve180and the five-way valve190so that the thermal management circuit100has the battery heating communication pattern shown inFIG.4.

In step S4, the ECU500determines whether the temperature of the battery173detected by the battery temperature sensor175is higher than the temperature of the heat medium flowing in the battery circuit170detected by the heat medium temperature sensor176. When the temperature of the battery173is higher than the temperature of the heat medium (Yes in S4), the process proceeds to step S5. When the temperature of the battery173is equal to or lower than the temperature of the heat medium (No in S4), the process proceeds to step S6.

In step S5, the ECU500turns off the water pump171. When the water pump171is already off, the ECU500keeps the water pump171off. This reduces dissipation of heat generated by the battery173to the heat medium. The process then proceeds to step S7.

In step S6, the ECU500turns on the water pump171. When the water pump171is already on, the ECU500keeps the water pump171on. This allows the heat of the heat medium in the battery circuit170to be accumulated (stored) in the battery173. The process then proceeds to step S7.

In step S7, the ECU500determines whether there is a request to turn on the heater from the user of the electrified vehicle1a.When there is the request (Yes in S7), the process proceeds to step S8. When there is no such request (No in S7), the process proceeds to step S9. The ECU500may determine that there is the request, based on a signal that is sent to the ECU500when the user presses a button for turning on the heater.

In step S8, the ECU500determines whether the water pump171is on. When the water pump171is on (Yes in S8), the process proceeds to step S10. When the water pump171is not on (No in S8), the process proceeds to step S11.

In step S9, the ECU500turns off the heater. Turning off the heater means turning off the water pump111, the electric heater112, etc. When the heater is already off, the ECU500keeps the heater off. The process then proceeds to step S12.

In step S10, the ECU500turns on the compressor151. Therefore, in this case, heat from the battery173is supplied via the chiller160to the heater core114serving as the air conditioning circuit. When the compressor151is already on, the ECU500keeps the compressor151on. The process then proceeds to step S12.

In step S11, the ECU500stops the compressor151. Therefore, in this case, only the heat in the high temperature circuit110is used for the heater of the electrified vehicle1a.When the compressor151is already off, the ECU500keeps the compressor151off. The process then proceeds to step S12.

In step S12, the ECU500determines whether the temperature of the battery173detected by the battery temperature sensor175is equal to or higher than 10° C. When the temperature of the battery173is equal to or higher than 10° C. (Yes in S12), the process proceeds to step S13. When the temperature of the battery173is lower than 10° C. (No in S12), the process returns to step S4. The threshold in step S12may be a value other than 10° C. as long as it is equal to or higher than the threshold in step S2.

In step S13, the ECU500controls the five-way valve180and the five-way valve190to change the communication pattern of the thermal management circuit100from the battery heating communication pattern shown inFIG.4to a different communication pattern (e.g., a communication pattern suitable for traveling of the electrified vehicle1a). The process then ends.

As described above, in the first embodiment, the ECU500causes the second closed circuit20connecting the flow path170aand the flow path170bformed and disconnects the second closed circuit20, the flow path130a,and the flow path130bfrom each other to make them independent of each other during heating control of the battery173. The heat generated by self-heating of the battery173can therefore be stored in the second closed circuit20. The heat generated in the PCU133can be stored in the flow path130b.As a result, it is possible to efficiently perform self-heating of the battery173while allowing effective use of heat generated by the PCU133.

Heat generated by the motor and the PCU133can be stored in the flow path130bdisconnected from the battery173. As described above, when the temperature of the heat medium in the flow path130bis lower than the temperature of the battery173, the heat medium in the flow path130bis not allowed to flow into the battery173. Therefore, heating of the battery173is less likely to be inhibited. When the temperature of the heat medium in the flow path130bbecomes equal to or higher than the temperature of the battery173, the operation mode is switched to the mode in which the heat medium in the flow path130bflows into the battery173. Therefore, the temperature of the battery173can further be increased.

Second Embodiment

The configuration using the five-way valves180,190is described in the first embodiment. However, the configuration of the switching unit according to the present disclosure is not limited to this. The configuration in which the “switching device” according to the present disclosure is an eight-way valve280will be described in a second embodiment.

Overall Configuration

FIG.6shows an example of the overall configuration of a thermal management system2according to the second embodiment of the present disclosure. The thermal management system2is different from the thermal management system1(see FIG.1) according to the first embodiment in that the thermal management system2includes a thermal management circuit200instead of the thermal management circuit100and includes an ECU510instead of the ECU500.

The thermal management circuit200includes, for example, a chiller circuit210, a chiller220, a radiator circuit230, a refrigeration cycle240, a condenser250, a drive unit circuit260, a battery circuit270, and an eight-way valve280. The eight-way valve280is an example of the “switching device” of the present disclosure. The chiller220and the refrigeration cycle240are examples of the “chiller device” and the “air conditioning circuit” of the present disclosure, respectively.

The chiller circuit210includes a water pump (W/P)211. The chiller220is connected to (shared by) both the chiller circuit210and the refrigeration cycle240. The water pump211is an example of the “pump” of the present disclosure.

The radiator circuit230includes a radiator231and a bypass path230b.The refrigeration cycle240includes, for example, a compressor241, an electromagnetic valve242, electromagnetic valves244A,244B,245, and246(seeFIG.7), an evaporator247, a check valve248, and an accumulator249. The condenser250includes a water-cooled condenser251and an air-cooled condenser252(seeFIG.7), and the water-cooled condenser251is connected to both the refrigeration cycle240and the radiator circuit230.

The drive unit circuit260includes, for example, a water pump261, an SPU262, a PCU263, an oil cooler264, and a reservoir tank265. Instead of the oil cooler264, a transaxle may be provided in the drive unit circuit260. The PCU263and the oil cooler264are examples of the “drive device” of the present disclosure. A system including the PCU263, the oil cooler264, and the battery272is an example of the “traction system” of the present disclosure.

The battery circuit270includes, for example, advanced driver-assistance systems (ADAS)271, a battery272, a battery temperature sensor273, and a heat medium temperature sensor274. The battery272is an example of the “electrical storage device” of the present disclosure. The battery temperature sensor273and the heat medium temperature sensor274are examples of the “first temperature sensor” and the “second temperature sensor” of the present disclosure, respectively.

The eight-way valve280includes eight ports P21to P28(seeFIG.7), and is connected to the chiller circuit210, the radiator circuit230, the drive unit circuit260, and the battery circuit270.

The ECU510controls the thermal management circuit200. The ECU510includes a processor511, a memory512, a storage513, and an interface514.

Configuration of Thermal Management Circuit

FIG.7shows an example of the configuration of the thermal management circuit200according to the second embodiment. A heat medium circulating in the chiller circuit210flows through a path of “eight-way valve280(port P23)—water pump211—chiller220—eight-way valve280(port P25).”

The water pump211circulates the heat medium in the chiller circuit210according to a control command from the ECU510. The chiller220exchanges heat between the heat medium circulating in the chiller circuit210and a refrigerant circulating in the refrigeration cycle240. The eight-way valve280switches the path to which the chiller circuit210is connected according to a control command from the ECU510. The switching of the path by the eight-way valve280will be discussed in detail later.

In the example shown inFIG.7, the heat medium circulating in the radiator circuit230flows through a path of “eight-way valve (port P26)—water-cooled condenser251—bypass path230b—eight-way valve280(port P27).” The radiator231is disposed downstream of a grille shutter (not shown), and exchanges heat between air outside the vehicle and the heat medium.

The heat medium (gas-phase refrigerant or liquid-phase refrigerant) circulating in the refrigeration cycle240flows through one of first to fourth paths. The first path is a path of “compressor241—electromagnetic valve244A—air-cooled condenser252—check valve248—electromagnetic valve (expansion valve)245—evaporator247—accumulator249—compressor241.” The second path is a path of “compressor241—electromagnetic valve244A—air-cooled condenser252—check valve248—electromagnetic valve (expansion valve)246—chiller220—accumulator249—compressor241.” The third path is a path of “compressor241—electromagnetic valve244B—water-cooled condenser251—electromagnetic valve (expansion valve)245—evaporator247—accumulator249—compressor241.” The fourth path is a path of “compressor241—electromagnetic valve244B—water-cooled condenser251—electromagnetic valve246—chiller220—accumulator249—compressor241.”

The compressor241compresses the gas-phase refrigerant circulating in the refrigeration cycle240according to a control command from the ECU510. The electromagnetic valve242is connected in parallel with the compressor241, and adjusts the amount of gas-phase refrigerant flowing into the compressor241according to a control command from the ECU510. The electromagnetic valves244A,244B selectively allow the gas-phase refrigerant discharged from the compressor241to flow into either the water-cooled condenser251or the air-cooled condenser252according to a control command from the ECU510. The water-cooled condenser251exchanges heat between the gas-phase refrigerant discharged from the compressor241and the heat medium flowing in the radiator circuit230. The air-cooled condenser252exchanges heat with air introduced into a vehicle cabin to produce warm air. The electromagnetic valve245restricts the flow of the liquid-phase refrigerant into the evaporator247according to a control command from the ECU510. The electromagnetic valve246restricts the flow of the liquid-phase refrigerant into the chiller220according to a control command from the ECU510. The electromagnetic valves245,246also have a function to expand the liquid-phase refrigerant. The accumulator249removes the liquid-phase refrigerant from the refrigerant in a gas-liquid mixed state. The accumulator249thus prevents the liquid-phase refrigerant from being sucked into the compressor241when the refrigerant is not completely evaporated by the evaporator247.

The heat medium (coolant) circulating in the drive unit circuit260flows through a path of “eight-way valve280(port P28)—reservoir tank265—water pump261—SPU262—PCU263—oil cooler264—eight-way valve280(port P22).”

The water pump261circulates the heat medium in the drive unit circuit260according to a control command from the ECU510. The SPU262controls charge and discharge of the battery272according to a control command from the ECU510. The PCU263converts DC power supplied from the battery272to AC power to supply the AC power to a motor (not shown) contained in the transaxle according to a control command from the ECU510. The oil cooler264cools the transaxle through heat exchange between the heat medium circulating in the drive unit circuit260and lubricating oil for the motor. Heat exchange may be performed between heat generated by supplying power to a stator without rotating a rotor of the motor and the heat medium circulating in the drive unit circuit260. The SPU262, the PCU263, and the oil cooler264are cooled by the heat medium circulating in the drive unit circuit260. The reservoir tank265stores part of the heat medium circulating in the drive unit circuit260(heat medium that has overflowed due to a pressure increase) to maintain the pressure and amount of heat medium in the drive unit circuit260.

The heat medium (coolant) circulating in the battery circuit270flows through a path of “eight-way valve280(port P21)—ADAS271—battery272—eight-way valve280(port P24).”

The ADAS271includes, for example, adaptive cruise control (ACC), auto speed limiter (ASL), lane keeping assist (LKA), pre-crash safety (PCS), and lane departure alert (LDA). The battery circuit270may include an autonomous driving system (ADS) in addition to the ADAS271. The battery272supplies traction power to the motor contained in the transaxle. The battery temperature sensor273detects the temperature of the battery272. The heat medium temperature sensor274detects the temperature of the heat medium flowing in the battery circuit270(flow path270athat will be described later).

As shown inFIGS.8A and8B, the chiller220is provided in a flow path210a(seeFIG.8B) of the chiller circuit210. The flow path210ais a flow path connecting the ports P23, P25of the eight-way valve280. The flow path210ais an example of the “fourth flow path” of the present disclosure.

The radiator231is provided in a flow path230a(seeFIG.8B) of the radiator circuit230. The flow path230aconnects the radiator231and the eight-way valve280. The flow path230ais in parallel with the bypass path230b.The bypass path230bconnects a portion between the water-cooled condenser251and the radiator231and the eight-way valve280. When the heat medium flows through the bypass path230b,the heat medium does not flow through the radiator231(flow path230a). When the heat medium flows through the radiator231(flow path230a), the heat medium does not flow through the bypass path230b.The flow path230ais an example of the “third flow path” of the present disclosure.

The water pump261, the SPU262, the PCU263, the oil cooler264, and the reservoir tank265(only the water pump261and the PCU263are representatively shown inFIGS.8A and8B) are provided in a flow path260a(seeFIG.8B) of the drive unit circuit260. The flow path260ais a flow path connecting the ports P28, P22of the eight-way valve280. The flow path260ais an example of the “second flow path” of the present disclosure.

The battery272is provided in the flow path270a(seeFIG.8B) of the battery circuit270. The flow path270ais a flow path connecting the ports P21, P24of the eight-way valve280. The flow path270ais an example of the “first flow path” of the present disclosure.

Communication Patterns

FIGS.8A,8BandFIGS.9A,9Bare conceptual diagrams showing an overview of a first communication pattern and a second communication pattern of the eight-way valve280, respectively. The first communication pattern is an example of the “heating circuit” of the present disclosure.

In the first communication pattern (seeFIGS.8A and8B), an internal flow path281of the eight-way valve280forms a path communicating between the port P25and the port P21. In the first communication pattern, an internal flow path282of the eight-way valve280forms a path communicating between the port P24and the port P23. In the first communication pattern, an internal flow path283of the eight-way valve280forms a path communicating between the port P27and the port P28. In the first communication pattern, an internal flow path284of the eight-way valve280forms a path communicating between the port P22and the port P26. In the first communication pattern, the bypass path230band the port P27of the eight-way valve280are connected.

The bypass path230band the flow path260ain which the PCU263etc. are provided are thus connected via the eight-way valve280. As a result, a first closed circuit30(seeFIG.8B) is formed. The flow path210ain which the chiller220is provided and the flow path270ain which the battery272etc. are provided are connected via the eight-way valve280. As a result, a second closed circuit40(seeFIG.8B) is formed. The second closed circuit40is an example of the “connection flow path” of the present disclosure.

In the example shown inFIGS.8A and8B, the radiator231(flow path230a), the first closed circuit30, and the second closed circuit40are disconnected from and independent of each other.

As shown inFIG.8A, the eight-way valve280has a circular shape as viewed perpendicularly to the plane of the paper. The eight-way valve280is configured to rotate clockwise or counterclockwise.

FIG.9Ashows the second communication pattern with the eight-way valve280rotated counterclockwise by about 10 degrees from the state shown inFIG.8A. In this case, the internal flow path283of the eight-way valve280is disconnected from the bypass path230band is connected to the flow path230a.The connection states of the internal flow paths281,282, and284do not change from the states shown inFIG.8A.

As a result, as shown inFIG.9B, the heat medium flows through a flow path of “radiator231—eight-way valve280—water pump261—PCU263—eight-way valve280—water-cooled condenser251.”

Therefore, it is possible to easily switch between the first communication pattern (seeFIGS.8A and8B) and the second communication pattern (seeFIGS.9A and9B) by rotating the eight-way valve280.

Method for Controlling Thermal Management Circuit

A method for controlling the thermal management system2will be described with reference to the flowchart ofFIG.10. The flow shown inFIG.10is merely illustrative, and the control in the present disclosure is not limited to the example shown inFIG.10. Description of the same steps as those in the control flow of the first embodiment will be simplified or omitted.

In step S22after S1, the ECU510determines whether the temperature of the battery272detected by the battery temperature sensor273is lower than 10° C. When the temperature of the battery272is lower than 10° C. (Yes in S22), the process proceeds to step S23. When the temperature of the battery272is equal to or higher than 10° C. (No in S22), the process ends. The threshold in step S22may be a value other than 10° C.

In step S23, the ECU510controls the eight-way valve280so that the thermal management circuit200has the first communication pattern shown inFIGS.8A and8B. Specifically, the ECU510rotates the eight-way valve280to form the first communication pattern.

In step S24, the ECU510determines whether the temperature of the battery272detected by the battery temperature sensor273is higher than the temperature of the heat medium flowing in the battery circuit270detected by the heat medium temperature sensor274. When the temperature of the battery272is higher than the temperature of the heat medium (Yes in S24), the process proceeds to step S25. When the temperature of the battery272is equal to or lower than the temperature of the heat medium (No in S24), the process proceeds to step S26.

In step S25, the ECU510turns off the water pump211. When the water pump211is already off, the ECU510keeps the water pump211off. The process then proceeds to step S27.

In step S26, the ECU510turns on the water pump211. When the water pump211is already on, the ECU510keeps the water pump211on. The process then proceeds to step S27.

In step S27, the ECU510determines whether there is a request to turn on the heater from the user of the electrified vehicle1a.When there is the request (Yes in S27), the process proceeds to step S28. When there is no such request (No in S27), the process proceeds to step S29.

In step S28, the ECU510determines whether the water pump211is on. When the water pump211is on (Yes in S28), the process proceeds to step S30. When the water pump211is not on (No in S28), the process proceeds to step S31.

In step S29, the ECU510turns off the heater. Turning off the heater means disabling the heating function in the refrigeration cycle240. When the heater is already off, the ECU510keeps the heater off. The process then proceeds to step S33.

In step S30, the ECU510turns on the compressor241. Therefore, in this case, heat from the battery272is supplied via the chiller220to the condenser250(air-cooled condenser252) serving as the air conditioning circuit. When the compressor241is already on, the ECU510keeps the compressor241on. The process then proceeds to step S33.

In step S31, the ECU510turns on the water pump211. In step S32, the ECU510turns on the compressor241.

In step S33, the ECU510determines whether the temperature of the battery272detected by the battery temperature sensor273is equal to or higher than 10° C. When the temperature of the battery272is equal to or higher than 10° C. (Yes in S33), the process proceeds to step S34. When the temperature of the battery272is lower than 10° C. (No in S33), the process returns to step S24. The threshold in step S33may be a value other than 10° C. as long as it is equal to or higher than the threshold in step S22.

In step S34, the ECU510controls the eight-way valve280to change the communication pattern of the thermal management circuit200from the first communication pattern shown inFIGS.8A and8Bto a different communication pattern (e.g., a communication pattern suitable for traveling of the electrified vehicle1a) such as the second communication pattern (seeFIGS.9A and9B). The process then ends.

Other configurations and effects of the second embodiment are the same as those of the first embodiment.

Third Embodiment

Unlike the second embodiment using the eight-way valve280, a third embodiment uses two six-way valves. The same components as those of the second embodiment are denoted by the same signs, and description thereof will not be repeated.

Overall Configuration

FIG.11shows an example of the overall configuration of a thermal management system3according to the third embodiment of the present disclosure. The thermal management system3is different from the thermal management system2(seeFIG.6) according to the second embodiment in that the thermal management system3includes a thermal management circuit300instead of the thermal management circuit200and includes an ECU520instead of the ECU510.

The thermal management circuit300includes, for example, the chiller circuit210, the chiller220, the radiator circuit230, the refrigeration cycle240, the condenser250, the drive unit circuit260, the battery circuit270, a six-way valve380, and a six-way valve390. Each of the six-way valve380and the six-way valve390is an example of the “switching device” of the present disclosure.

The chiller220is provided in a flow path210bof the chiller circuit210. The flow path210bconnects the chiller circuit210and each of the six-way valves380,390. The flow path210bis an example of the “fourth flow path” of the present disclosure.

The radiator231is provided in a flow path230c.The flow path230cconnects the radiator231and the six-way valve390. The flow path230cis an example of the “third flow path” of the present disclosure.

The water pump261, the SPU262, the PCU263, the oil cooler264, and the reservoir tank265are provided in a flow path260bof the drive unit circuit260. The flow path260bconnects the drive unit circuit260and each of the six-way valves380,390. The flow path260bis an example of the “second flow path” of the present disclosure.

The battery272is provided in a flow path270bof the battery circuit270. The flow path270bconnects the battery circuit270and the six-way valve380. The flow path270bis an example of the “first flow path” of the present disclosure.

The ECU520controls the thermal management circuit300. The ECU520includes a processor521, a memory522, a storage523, and an interface524.

Configuration of Thermal Management Circuit

FIG.12shows an example of the configuration of the thermal management circuit300according to the third embodiment. As shown inFIG.12, the six-way valve380includes six ports P31to P36. The six-way valve390includes six ports P41to P46.

The six-way valve380is connected to the six-way valve390. Specifically, the port P35of the six-way valve380and the port P45of the six-way valve390are connected by a flow path5. The port P36of the six-way valve380and the port P46of the six-way valve390are connected by a flow path6.

A heat medium circulating in the chiller circuit210flows through a path of “six-way valve380(port P33)—water pump211—chiller220—six-way valve390(port P43).”

The heat medium circulating in the radiator circuit230flows through a path of “six-way valve390(port P41)—water-cooled condenser251—radiator231—six-way valve390(port P44).”

The heat medium (coolant) circulating in the drive unit circuit260flows through a path of “six-way valve390(port P42)-reservoir tank265—water pump261—SPU262—PCU263—oil cooler264—six-way valve380(port P32).”

The heat medium (coolant) circulating in the battery circuit270flows through a path of “six-way valve380(port P31)—ADAS271—battery272—six-way valve380(port P34).”

Communication Patterns

FIG.13is a conceptual diagram showing an overview of a battery heating communication pattern of the thermal management circuit300that is formed by controlling the six-way valve380and the six-way valve390. In the communication pattern shown inFIG.13, the six-way valve380forms a path communicating between the port P35and the port P32, a path communicating between the port P36and the port P31, and a path communicating between the port P33and the port P34. The battery heating communication pattern is an example of the “heating circuit” of the present disclosure.

In the communication pattern shown inFIG.13, the six-way valve390forms a path communicating between the port P42and the port P45and a path communicating between the port P43and the port P46.

As a result, a first closed circuit50is formed by the flow path260bin which the PCU263etc. are provided, the six-way valve380, and the six-way valve390. A second closed circuit60is formed by the flow path210bin which the chiller220is provided, the flow path270bin which the battery272etc. are provided, the six-way valve380, and the six-way valve390. The second closed circuit60is an example of the “connection flow path” of the present disclosure.

Method for Controlling Thermal Management Circuit

A method for controlling the thermal management system3will be described with reference to the flowchart ofFIG.14. Description of the same steps as those in the control flow of the second embodiment will not be repeated.

When Yes in step S22, the process proceeds to step S43. In step S43, the ECU520controls the six-way valve380and the six-way valve390so that the thermal management circuit300has the battery heating communication pattern shown inFIG.13.

When Yes in step S33, the process proceeds to step S44. In step S44, the ECU520controls the six-way valve380and the six-way valve390to change the communication pattern of the thermal management circuit300from the battery heating communication pattern shown inFIG.13to a different communication pattern (e.g., a communication pattern suitable for traveling of the electrified vehicle1a). The process then ends.

Other configurations and effects of the third embodiment are the same as those of the second embodiment.

The first to third embodiments illustrate an example in which battery heating control is performed at the start of driving the electrified vehicle1a(when the traction system is activated). However, the present disclosure is not limited to this. The heating control may be started a predetermined time (e.g., 30 minutes) before the scheduled start time of the following trip.

As shown inFIG.15, the heating control may be performed at the start of external charging (e.g., fast charging). External charging refers to charging the battery with charging power supplied from charging equipment (not shown) external to the electrified vehicle. For example, when the ECU500detects a charging plug plugged in step S51, the process proceeds to step S2. When it is determined in step S12or S2that the temperature of the battery173is equal to or higher than 10° C., the process proceeds to step S52. Note that 10° C. is an example of the “predetermined temperature” of the present disclosure. In step S52, the ECU500starts controlling external charging (fast charging).FIG.15illustrates an example in which plugging in triggers the battery heating control. However, even before plugging in, the battery heating control may be started, for example, a predetermined time (e.g., 10 minutes) before the scheduled start time of external charging (scheduled start time of supplying charging power).FIG.15representatively illustrates an example in which the above control is applied to the first embodiment. However, the above control may be applied to the second and third embodiments.

The first to third embodiments illustrate an example in which the thermal management system is mounted on an electrified vehicle. However, the present disclosure is not limited to this. The thermal management system may be mounted on an electrical apparatus different from an electrified vehicle (e.g., a stationary electrical storage device).

The first to third embodiments illustrate an example in which the following two controls are performed: the control for switching the operating state of the chiller based on whether there is a heating request, and the control for switching the operating state of the water pump based on the comparison result between the temperature of the battery and the temperature of the heat medium. However, the present disclosure is not limited to this. Only one of the two controls may be performed. Alternatively, neither of the two controls may be performed.

The first embodiment illustrates an example in which the thermal management circuit100includes the high temperature circuit110. However, the present disclosure is not limited to this. The thermal management circuit100may not include the high temperature circuit110(seeFIG.16). The thermal management circuit200of the second embodiment and the thermal management circuit300of the third embodiment may include a high temperature circuit having the same function as the high temperature circuit110(seeFIGS.17and18).

The first to third embodiments illustrate an example in which battery heating control is performed at the start of driving the electrified vehicle1a(when the traction system is activated). However, the present disclosure is not limited to this. The heating control may be performed other than at the start of driving the electrified vehicle1a(when the traction system is activated). For example, the heating control may be performed when the battery temperature falls below a predetermined threshold (10° C. in the above embodiment). In this case, the ECU may acquire the detected value of the battery temperature at predetermined intervals (e.g., every hour). The battery may be heated by causing a current larger than normal to flow through the battery with the battery heating communication pattern formed during traveling of the electrified vehicle1a.

The configurations (processes) of the above embodiments and modifications may be combined.

The battery heating control will be described in detail with reference toFIG.19. The battery173is connected to a converter810via a system main relay (SMR)800. The converter810is connected to an inverter820. The inverter820is connected to a motor830. A discharge circuit840including a switch and a resistive element is connected to the battery173. A smoothing capacitor850is provided between the battery173and the converter810. A discharge circuit860composed of a switch and a resistive element is connected in parallel with the smoothing capacitor850.FIG.19is representatively illustrated based on the configuration of the first embodiment. However, the same configuration may be applied to the second and third embodiments.

The heating control for the battery173may include, for example, a control for electrically disconnecting the SMR800and turning on the switch of the discharge circuit840. In this case, a current flows through the closed circuit formed by the battery173and the discharge circuit840. The heating control for the battery173may include a control for turning off the switch of the discharge circuit840and turning on the SMR800and the switch of the discharge circuit860. In this case, a current flows through the closed circuit formed by the battery173, the SMR800, and the discharge circuit860. The heating control for the battery173may include a control for causing a current adjusted so that no torque is generated in the motor830to flow with the SMR800turned on and the switches of the discharge circuits840,860turned off.

The embodiments disclosed herein should be construed as illustrative in all respects and not restrictive. The scope of the present disclosure is set forth in the claims rather than in the above description of the embodiments, and is intended to include all modifications within the meaning and scope equivalent to those of the claims.