Battery temperature control device

Abstract

When the temperature TB of the battery is higher than or equal to a threshold value S and there is a request to cool the battery, the battery is cooled in a second cooling mode in a region where the outside air temperature To is lower than or equal to a threshold value S2. In the second cooling mode, the battery is cooled by heat dissipation from the low-temperature radiator. When the temperature TB is higher than or equal to a threshold value S3, the battery is cooled in a first cooling mode in which the battery is cooled using a refrigeration cycle (refrigerant circuit). In a region where the temperature TB is lower than the threshold value S3 and the outside air temperature To is higher than the threshold value S2, cooling mode switching control is performed.

Description

Technical Field

[0001] This disclosure relates to a battery temperature control device. Background Technology

[0002] Japanese Unexamined Patent Application Publication No. 2020-185829 (JP 2020-185829 A) discloses an on-board temperature control device that controls, for example, the temperature of a battery that powers a motor. This on-board temperature control device uses a cooling cycle (cooling circuit) to cool the battery, and also utilizes heat dissipation from a radiator to cool the battery. Summary of the Invention

[0003] When there is a need to cool the battery and the battery temperature is high, it is preferable to use a refrigeration cycle for cooling to properly cool the battery. However, when the compressor of the refrigeration cycle is driven by power from the battery, the power from the battery is consumed for cooling, which reduces the vehicle's driving range. When there is a need to cool the battery but the battery temperature is relatively low, the battery can be cooled by using heat dissipation from the radiator to maintain the battery at an appropriate temperature. However, when using heat dissipation from the radiator to cool the battery, the cooling performance may decrease in high ambient temperatures (potentially failing to ensure sufficient cooling), making it difficult to maintain the battery at an appropriate temperature. Therefore, it is desirable to appropriately select between battery cooling using a refrigeration cycle and battery cooling using heat dissipation from the radiator.

[0004] The purpose of this disclosure is to make an appropriate choice between battery cooling using a refrigeration cycle and battery cooling using heat dissipation from a radiator.

[0005] The battery temperature control device disclosed herein includes: a battery thermal circuit configured to circulate a heat transfer medium to control the battery temperature; and a control device configured to select between a first cooling mode and a second cooling mode. The first cooling mode is a mode in which the battery is cooled by using a refrigeration cycle to cool the heat transfer medium. The second cooling mode is a mode in which the battery is cooled by dissipating heat from the heat transfer medium to the outside air via a heat sink. The control device is configured to select the second cooling mode when the temperature of the heat transfer medium is below or equal to a target temperature, and to select the first cooling mode when the temperature of the heat transfer medium remains above the target temperature for a predetermined time or longer, provided that a request to cool the battery exists and the battery temperature is below or equal to a first set temperature and the outside air temperature is above or equal to a second set temperature.

[0006] In this configuration, the battery temperature is controlled by a heat transfer medium circulating through the battery's thermal loop. The control device cools the battery by selecting between a first cooling mode and a second cooling mode. In the first cooling mode, the battery is cooled by using a refrigeration cycle to cool the heat transfer medium. In the second cooling mode, the battery is cooled by dissipating the heat from the heat transfer medium to the outside air via a heat sink. When the battery temperature is below or equal to the first set temperature, the battery temperature is relatively low. Therefore, the second cooling mode can maintain the battery at an appropriate temperature. When the outside air temperature is above or equal to the second set temperature, the cooling performance of the second cooling mode may decrease, and the battery may not be able to maintain an appropriate temperature.

[0007] When a request to cool the battery is received, and the battery temperature is below or equal to a first set temperature while the outside air temperature is above or equal to a second set temperature, the control device selects a second cooling mode when the temperature of the heat transfer medium is below or equal to the target temperature. Since the temperature of the heat transfer medium is below or equal to the target temperature, and the amount of heat transferred from the battery to the heat transfer medium is relatively large, the battery can be kept at an appropriate temperature using the second cooling mode.

[0008] When a request to cool the battery is received, and the battery temperature is below or equal to a first set temperature while the outside air temperature is above or equal to a second set temperature, the control device selects a first cooling mode if the temperature of the heat transfer medium remains above the target temperature for a predetermined time or longer. If the temperature of the heat transfer medium remains above the target temperature for a predetermined time or longer, it can be determined that the cooling performance of the second cooling mode is insufficient. Therefore, cooling is performed in the first cooling mode. As a result, the battery can be maintained at an appropriate temperature. Therefore, a suitable choice can be made between battery cooling using a refrigeration cycle and battery cooling using heat dissipation from a radiator.

[0009] The control device can be configured to set the target temperature based on the battery's input or output current.

[0010] The heat generated by the battery increases with the increase of the battery's input or output current. Using this configuration, the target temperature of the heat transfer medium can be set by taking into account the heat generated by the battery. Therefore, a suitable choice can be made between battery cooling using a refrigeration cycle and battery cooling using heat dissipation from a radiator.

[0011] The control device can be configured to select a second cooling mode when the outside air temperature is lower than a second set temperature.

[0012] In this configuration, when the outside air temperature is lower than the second set temperature and the cooling performance of the second cooling mode is high, the battery is cooled in the second cooling mode. This reduces the energy consumption of the cooling cycle.

[0013] The control device can be configured to select a first cooling mode when the battery temperature is higher than a first set temperature.

[0014] In this configuration, when the battery temperature is higher than a first set temperature and a cooling cycle is preferably used to cool the battery appropriately, the battery is cooled in a first cooling mode. Therefore, the battery can be maintained at an appropriate temperature.

[0015] The control device can be configured to select a first cooling mode when the outside air temperature is higher than or equal to a third set temperature that is higher than a second set temperature.

[0016] In this configuration, when the outside air temperature is higher than the third set temperature and cooling of the battery through heat dissipation from the radiator cannot be expected, the battery is cooled in the first cooling mode. Therefore, the battery can be maintained at an appropriate temperature.

[0017] According to this disclosure, a suitable choice can be made between battery cooling using a refrigeration cycle and battery cooling using heat dissipation from a radiator. Attached Figure Description

[0018] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, wherein like symbols denote like elements, and wherein: Figure 1 A schematic configuration of a battery temperature control device according to an embodiment is shown; Figure 2 The first cooling mode according to the implementation scheme is shown; Figure 3 A second cooling mode according to the implementation scheme is shown; Figure 4 This is a flowchart illustrating the battery cooling control process performed by the electronic control unit (ECU); Figure 5 This is a flowchart illustrating the process of cooling mode switching control; and Figure 6 It is a graph showing the area of ​​the cooling mode according to the implementation scheme. Detailed Implementation

[0019] Embodiments of this disclosure will be described in detail with reference to the accompanying drawings. In all the drawings, the same or corresponding parts are represented by the same symbols and their descriptions will not be repeated.

[0020] Figure 1A schematic configuration of a battery temperature control device 10 according to this embodiment is shown. In this embodiment, the battery temperature control device 10 controls the temperature of a battery 200 mounted on a vehicle 1. The vehicle 1 is an electrified vehicle, and may be, for example, a battery electric vehicle. However, the vehicle 1 may alternatively be another type of electrified vehicle, such as a plug-in hybrid electric vehicle, or may be an industrial vehicle.

[0021] The battery temperature control device 10 includes a thermal management circuit 100 and an electronic control unit (ECU) 500. The ECU 500 includes a processor 501 and a memory 502. The processor 501 executes programs stored in the memory 502 to perform various types of thermal management controls, including temperature control of the battery 200. The ECU 500 is an example of a "control device" in this disclosure.

[0022] The battery temperature control device 10 is configured to perform thermal management of the vehicle 1 using the heat transfer medium in the thermal management circuit 100. The battery temperature control device 10 also functions as a thermal management device for the vehicle. The thermal management circuit 100 includes a first circuit 110, a second circuit 120, a condenser 140, a refrigerant circuit 150, a cooler 160, and a water-to-water heat exchanger 170. The second circuit 120 is an example of the "battery thermal circuit" of this disclosure and controls the temperature of the battery 200.

[0023] The first circuit 110 includes a first channel through which the high-temperature heat transfer medium flows. The first circuit 110 includes a pump 111, an electric heater 112 for heating, a four-way valve 113, a heater core 114, a storage tank (R / T) 115, and a high-temperature radiator 118. The four-way valve 113 is controlled by an ECU 500 to switch the flow path of the high-temperature heat transfer medium. The pump 111 circulates the high-temperature heat transfer medium through the first circuit 110. The high-temperature heat transfer medium exchanges heat with each device as it passes through. The heater core 114 serves as the heating source (heat source) for the air conditioning unit 2. The high-temperature heat transfer medium can be, for example, a long-life coolant (LLC).

[0024] Five-way valve 310 switches the flow path of the cryogenic heat transfer medium flowing through the second circuit 120. The cryogenic heat transfer medium can be insulating oil or an electrically insulating (low conductivity) antifreeze. The cryogenic heat transfer medium is the "heat transfer medium" of this disclosure. The cryogenic heat transfer medium exchanges heat with various devices. Therefore, each device includes (or functions as) a heat exchanger. Five-way valve 310 includes five ports P1 to P5. ECU 500 controls five-way valve 310.

[0025] Channels 120a and 120b are connected to ports P1 and P2 of the five-way valve 310, respectively. Channel 120a connects port P1 to storage tank 320. Channel 120b connects port P2 to storage tank 320.

[0026] Pump 121, water-to-water heat exchanger 170, and cooler 160 are disposed in channel 120a. Battery 200 is disposed in channel 120b. When ports P1 and P2 are connected and pump 121 is operating, the low-temperature heat transfer medium circulates through channels 120a and 120b. In cooler 160, the low-temperature heat transfer medium dissipates heat (the low-temperature heat transfer medium is cooled), thereby cooling battery 200. In water-to-water heat exchanger 170, the low-temperature heat transfer medium absorbs heat (the low-temperature heat transfer medium is heated by the high-temperature heat transfer medium), thereby heating battery 200.

[0027] Battery 200 is a traction battery for vehicle 1 and may be, for example, a lithium-ion battery. Battery 200 is configured to be charged via an external power source (not shown). Battery 200 is provided with a monitoring unit 50. Monitoring unit 50 detects battery temperature TB, battery voltage VB, and battery input or output current IB, and outputs them to ECU 500. Monitoring unit 50 also calculates the state of charge (SOC) of battery 200 and outputs it to ECU 500.

[0028] Channels 120c and 120d are connected to ports P4 and P5 of the five-way valve 310, respectively. Channels 120c and 120d connect ports P4 and P5 to the cryogenic radiator 128, respectively. Pump 122, power supply unit (ESU) 123, power control unit (PCU) 124, and electric generator (MG) 125 are arranged in channel 120c. MG 125 is a traction motor for vehicle 1 and uses power from battery 200 to drive vehicle 1. When ports P4 and P5 are connected and pump 122 is operating, the cryogenic heat transfer medium circulates through channels 120c and 120d. The cryogenic heat transfer medium exchanges heat with ESU 123, PCU 124, and MG 125, and dissipates heat from ESU 123, PCU 124, and MG 125 to the outside air via cryogenic radiator 128. ESU 123, PCU 124 and MG 125 are therefore cooled.

[0029] The refrigerant circulates through refrigerant circuit 150. The refrigerant can be, for example, hydrofluorocarbons (HFCs), ammonia, or carbon dioxide. Refrigerant circuit 150 includes a compressor 151, an electric expansion valve 152, an evaporator 153, an evaporative pressure regulator (EPR) 154, and an electric expansion valve 155. Compressor 151 compresses and discharges the refrigerant that has already flowed out of evaporator 153 and cooler 160. Refrigerant circuit 150 is a refrigeration cycle. Refrigerant circuit 150 corresponds to the "refrigeration cycle" of this disclosure.

[0030] Evaporator 153 serves as the cooling source for air conditioning unit 2. Condenser 140 is connected to both the first circuit 110 and the refrigerant circuit 150 and serves as a heat exchanger. During operation of the refrigeration cycle (when compressor 151 is operating), condenser 140 facilitates heat exchange between the high-temperature heat transfer medium flowing through the first circuit 110 and the refrigerant circulating through the refrigerant circuit 150. Cooler 160 is connected to both the refrigerant circuit 150 and channel 120a and serves as a heat exchanger. Cooler 160 facilitates heat exchange between the refrigerant circulating through the refrigerant circuit 150 and the low-temperature heat transfer medium flowing through the second circuit 120 (channel 120a). As described above, condenser 140, refrigerant circuit 150, and cooler 160 are configured to facilitate heat transfer between the high-temperature heat transfer medium flowing through the first circuit 110 and the low-temperature heat transfer medium flowing through the second circuit 120.

[0031] The air conditioning unit 2 can use the heat dissipated from the condenser 140 to heat the passenger compartment. During the heating operation of the air conditioning unit 2, ports Pa and Pb of the four-way valve 113 are connected, and the high-temperature heat transfer medium that has absorbed heat in the condenser 140 dissipates heat in the heater core 114. Heating is thus achieved.

[0032] Figure 2 A first cooling mode according to this embodiment is shown. The first cooling mode is a mode in which the battery 200 is cooled using a refrigeration cycle (refrigerant circuit 150). In the first cooling mode, ports P1 and P2 of the five-way valve 310 are connected, and ports Pa and Pb of the four-way valve 113 are connected. The compressor 151, pump 111, and pump 121 are then operated. Figure 2 In the diagram, the long and short dashed lines with arrows indicate the flow of the first circuit 110 (high-temperature heat transfer medium), the second circuit 120 (low-temperature heat transfer medium), and the refrigerant circuit 150 (refrigerant).

[0033] In the first cooling mode, the refrigeration cycle (refrigerant circuit 150) operates, and in the condenser 140, the refrigerant dissipates heat to the high-temperature side heat transfer medium in the first circuit 110 and condenses. Then, in the cooler 160, the refrigerant absorbs heat from the low-temperature side heat transfer medium in the channel 120a and evaporates. The high-temperature heat transfer medium, which has absorbed heat from the refrigerant in the condenser 140 and become hot, circulates through the first circuit 110 and dissipates the heat to the outside air via the high-temperature radiator 118. The high-temperature heat transfer medium is thus cooled.

[0034] In the second circuit 120, the low-temperature heat transfer medium of the refrigerant (refrigerant circuit 150) that has lost heat to the cooler 160 exchanges heat with the battery 200 (absorbs heat from the battery 200), thereby cooling the battery 200.

[0035] Figure 3 A second cooling mode according to the embodiment is shown. The second cooling mode cools the battery 200 by dissipating heat from the low-temperature radiator 128. In the second cooling mode, ports P1 and P5 of the five-way valve 310 are connected, and ports P2 and P4 are connected. Pumps 121 and 122 are then operated. Figure 3 In the diagram, the long and short dashed lines with arrows indicate the flow of the second loop 120 (the low-temperature side heat transfer medium).

[0036] In the second cooling mode, the low-temperature side heat transfer medium, which has already exchanged heat with the battery 200 (has absorbed heat from the battery 200), dissipates the heat to the outside air via the low-temperature radiator 128. The low-temperature side heat transfer medium, cooled by heat dissipation to the outside air, circulates through the second loop 120 and cools the battery 200. The low-temperature radiator 128 is an example of a "radiator" in this disclosure.

[0037] In this embodiment, pump 111, electric heater 112, pump 121, pump 122, and compressor 151 are driven by electricity from battery 200. Alternatively, these devices may be driven by electricity from an auxiliary battery that is charged using electricity from battery 200.

[0038] When there is a request to cool the battery 200 and the battery 200 temperature is high, cooling in the first cooling mode of the refrigeration cycle is preferred to properly cool the battery 200. However, the compressor 151 operating the refrigeration cycle (refrigerant circuit 150) consumes power from the battery 200, which reduces the driving range of the vehicle 1. When there is a request to cool the battery 200 but the battery 200 temperature is relatively low, cooling the battery 200 in a second cooling mode using heat dissipation from the low-temperature radiator 128 can maintain the battery 200 at an appropriate temperature. However, in high ambient temperature environments, the heat dissipated from the low-temperature radiator 128 is reduced. Therefore, the cooling performance of the second cooling mode may be reduced (it may not be able to ensure sufficient cooling), making it difficult to maintain the battery 200 at an appropriate temperature. Therefore, it is desirable to appropriately select between the first and second cooling modes.

[0039] Figure 4 This is a flowchart illustrating the battery cooling control process performed by ECU 500. The flowchart is repeated at predetermined intervals when the vehicle 1 is in motion (when the power switch (not shown) is turned on) and when the battery 200 is being charged externally.

[0040] In step 10 (hereinafter referred to as "step" or "S"), the temperature TB of the battery 200 and the external air temperature To are acquired. The temperature TB can be a value detected by the monitoring unit 50. The external air temperature To can be a value detected by the external air temperature sensor 12 (see [link to sensor]). Figure 1 The detected value.

[0041] In S11, it is determined whether the temperature TB is higher than the threshold S1. The threshold S1 is a temperature used to determine whether to cool the battery 200, and is preset through experiments, etc. When the temperature TB is lower than or equal to the threshold S1 ("No" in S11), it is determined that there is no request to cool the battery 200, and the process proceeds to S12. In S12, the flag F is set to zero, and the current routine ends. In this case, since there is no request to cool the battery 200, cooling of the battery 200 is not performed. When the temperature TB is higher than the threshold S1 ("Yes" in S11), there is a request to cool the battery 200, and the process proceeds to S13.

[0042] In S13, it is determined whether the external air temperature To is higher than a threshold S2. The threshold S2 is, for example, an external air temperature at which sufficient cooling performance of the battery 200 can be achieved even through heat dissipation from the low-temperature radiator 128. Alternatively, the threshold S2 can be set to an external air temperature low enough that operation of the compressor 151 might damage it due to insufficient oil. The threshold S2 is preset through experiments, etc. The threshold S2 can be, for example, 0°C.

[0043] If it is determined in S13 that the external air temperature To is lower than or equal to the threshold S2 (in S13, this is "No"), the process proceeds to S14. If it is determined in S13 that the external air temperature To is higher than the threshold S2 (in S13, this is "Yes"), the process proceeds to S15. The threshold S2 corresponds to the "second set temperature" of this disclosure.

[0044] In S14, the second cooling mode is selected, and then the process proceeds to S12. When the second cooling mode is selected, ports P1 and P5 of the five-way valve 310 are connected, and ports P2 and P4 are connected. Pumps 121 and 122 are then operated to reference... Figure 3 The second cooling mode described is used to cool battery 200.

[0045] In S15, it is determined whether the temperature TB is below a threshold S3. The threshold S3 is a temperature at which the battery 200 is reliably cooled with ideal high cooling performance, thereby reducing the likelihood that the temperature TB of the battery 200 will become excessively high and accelerate the degradation of the battery 200. The threshold S3 is preset through experiments, etc. When the temperature TB is higher than or equal to the threshold S3 ("No" in S15), the process proceeds to S16. When the temperature TB is lower than the threshold S3 ("Yes" in S15), the process proceeds to S17. The threshold S3 corresponds to the "first set temperature" of this disclosure.

[0046] In S16, the first cooling mode is selected, and then the process proceeds to S12. When the first cooling mode is selected, ports P1 and P2 of the five-way valve 310 are connected, and ports Pa and Pb of the four-way valve 113 are connected. Then, the compressor 151, pump 111, and pump 121 are operated, and a reference is used. Figure 2 The first cooling mode is described to cool battery 200.

[0047] In S17, it is determined whether flag F is 1. Flag F was set to zero in S12 and to 1 in S18. When S17 is executed before S18, flag F is zero ("No" in S17), and processing proceeds to S18. When S18 is executed in the previous routine, flag F is 1 ("Yes" in S17), and the program proceeds to S19.

[0048] In S18, the second cooling mode is selected, and the flag F is set to 1. Then, the process proceeds to S19. When the second cooling mode is selected, the battery 200 is cooled in the second cooling mode.

[0049] In S19, cooling mode switching control is executed. Figure 5 This is a flowchart illustrating the cooling mode switching control process. In S20, the input or output current IB of the battery 200 and the temperature Tbw of the low-temperature side heat transfer medium are acquired. The input or output current IB can be a value detected by the monitoring unit 50. The temperature Tbw is the temperature of the low-temperature side heat transfer medium flowing into the battery 200, and can be determined by the temperature sensor 13 (see [reference]) located in the channel 120b between port P2 of the five-way valve 310 and the battery 200. Figure 1 The detected value.

[0050] In S21, the square of the input or output current IB (IB^2) is calculated. Then, in S22, the requested cooling heat Chr is calculated based on IB^2. Ideally, for the battery 200 to cool, the heat transferred from the battery 200 to the low-temperature heat transfer medium should be greater than the heat generated by the battery 200. Since the heat (W) generated by the battery 200 is known to be expressed as R × IB^2 (where R represents the internal resistance of the battery 200), the requested cooling heat Chr can be calculated from a mapping using the square of the input or output current IB (IB^2) as a parameter.

[0051] Mappings can be prepared in advance through experiments, etc.

[0052] In S23, the target temperature Tt of the cryogenic heat transfer medium is calculated. The heat dissipated from the battery 200 varies according to the difference ΔT between temperature TB and the outside air temperature To, and the flow rate of the cryogenic heat transfer medium. The flow rate of the cryogenic heat transfer medium is determined by the capacity of pump 121 (and pump 122). Ideally, the difference ΔT is set to be larger as the requested cooling heat Chr increases. Therefore, as the requested cooling heat Chr increases, the target temperature Tt becomes lower. In S23, the calculation is performed from a mapping using the requested cooling heat Chr and temperature TB as parameters. The mapping can be preset through experiments, etc. As the requested cooling heat Chr increases and the temperature TB decreases, the target temperature Tt tends to become lower.

[0053] In S24, it is determined whether the temperature Tbw detected in S20 is higher than the target temperature Tt. When the temperature Tbw is lower than or equal to the target temperature Tt (Tbw≤Tt) (No in S24), the process proceeds to S25, where the counter C is set to zero. Then, the process proceeds to S26. In S26, the second cooling mode is selected, and the current routine ends.

[0054] When the temperature Tbw is higher than the target temperature Tt (Tbw>Tt) ("Yes" in S24), the process proceeds to S27. In S27, the counter C is incremented (1 is added to the counter C), and the process proceeds to S28.

[0055] In S28, it is determined whether the counter C is greater than the threshold S4. The threshold S4 is set such that even if the temperature Tbw remains higher than the target temperature Tt for the same or longer period of time as the threshold S4, the temperature TB of battery 200 will not decrease, and battery 200 may be adversely affected. The threshold S4 can be set through experiments, simulations, etc. When the counter C is less than or equal to the threshold S4 (C≤S4) ("No" in S28), the process proceeds to S26. When the counter C is greater than the threshold S4 (C>4) ("Yes" in S28), the process proceeds to S29. In S29, the first cooling mode is selected, and the current routine ends.

[0056] Figure 6 This is a graph showing the region of the cooling mode according to this embodiment. Figure 6 In the diagram, the vertical axis represents the temperature TB of battery 200, and the horizontal axis represents the outside air temperature To. In regions where temperature TB is below the threshold S1, there is no request to cool battery 200, and cooling of battery 200 is not performed. In regions where temperature TB is above or equal to the threshold S1, there is a request to cool battery 200. Therefore, battery 200 is cooled.

[0057] When a request to cool battery 200 is received (when temperature TB is higher than or equal to threshold S1), a second cooling mode is set in the region where the outside air temperature To is lower than or equal to threshold S2. In this region, heat from the low-temperature heat transfer medium is dissipated to the outside air via the low-temperature radiator 128 to cool battery 200. When the outside air temperature To is lower than threshold S2 and the cooling performance of the second cooling mode is high, battery 200 is cooled in the second cooling mode. This reduces the energy consumption of the refrigeration cycle.

[0058] In the region where the outside air temperature To is higher than threshold S2 and the temperature TB is higher than or equal to threshold S3, a first cooling mode is set, and a refrigeration cycle (refrigerant circuit 150) is used to cool the battery 200. When the temperature TB is higher than or equal to threshold S3, i.e., when the battery 200 is relatively hot, the refrigeration cycle is used to cool the battery 200 and maintain the battery 200 at an appropriate temperature.

[0059] In areas where temperature TB is below threshold S3 and outside air temperature To is above threshold S2, the first or second cooling mode is selected via cooling mode switching control (see [link]). Figure 5When the external air temperature To is higher than or equal to a threshold SS, a first cooling mode can be selected. The threshold SS can be the temperature TB of the battery 200. In an environment where the external air temperature To is higher than or equal to the temperature TB, it is difficult to cool the battery 200 by heat dissipation from the low-temperature heat sink 128. Therefore, when the external air temperature To is higher than or equal to the threshold SS, the first cooling mode can be selected before making a definitive determination of the cooling mode switching control in S28. The threshold SS is an example of the "third set temperature" of this disclosure.

[0060] In the cooling mode switching control, when the temperature Tbw of the low-temperature side heat transfer medium is lower than or equal to the target temperature Tt (when "No" is set in S24), the second cooling mode is selected. When the temperature Tbw is higher than the target temperature Tt for a predetermined time or longer (when the counter C exceeds the threshold S4 and a positive determination is made in S28), the first cooling mode is selected. When the temperature Tbw is lower than or equal to the target temperature Tt, the heat transferred from the battery 200 to the low-temperature side heat transfer medium is relatively large. Therefore, the battery 200 can be maintained at an appropriate temperature using the second cooling mode. When the temperature Tbw is higher than the target temperature Tt for a predetermined time or longer, it can be determined that the cooling performance of the second cooling mode is insufficient. Therefore, cooling is performed in the first cooling mode. Thus, the battery 200 can be maintained at an appropriate temperature.

[0061] The target temperature Tt is set based on the requested cooling heat Chr calculated according to the input or output current IB of the battery 200. Since the requested cooling heat Chr takes into account the heat generated by the battery 200, the target temperature Tt can be set based on the heat generated by the battery 200, and a first cooling mode or a second cooling mode can be appropriately selected.

[0062] The embodiments disclosed herein should be interpreted as illustrative rather than restrictive in all respects. The scope of this disclosure is set forth in the claims rather than in the foregoing description of the embodiments, and is intended to include all modifications that are equivalent in meaning and scope to the claims.

Claims

1. A battery temperature control device, comprising: A battery thermal circuit is configured to circulate a heat transfer medium to control the battery temperature. as well as A control device configured to select between a first cooling mode and a second cooling mode, wherein the first cooling mode is a mode in which the battery is cooled by cooling the heat transfer medium using a refrigeration cycle, and the second cooling mode is a mode in which the battery is cooled by dissipating the heat of the heat transfer medium to the outside air via a heat sink, wherein: The control device is configured to: When there is a request to cool the battery, and the battery temperature is below or equal to a first set temperature while the outside air temperature is above or equal to a second set temperature, When the temperature of the heat transfer medium is lower than or equal to the target temperature, the second cooling mode is selected, and When the temperature of the heat transfer medium is higher than the target temperature for a predetermined time or longer, the first cooling mode is selected.

2. The battery temperature control device according to claim 1, wherein, The control device is configured to set the target temperature based on the input or output current of the battery.

3. The battery temperature control device according to claim 1 or 2, wherein, The control device is configured to select the second cooling mode when the outside air temperature is lower than the second set temperature.

4. The battery temperature control device according to claim 3, wherein, The control device is configured to select the first cooling mode when the temperature of the battery is higher than the first set temperature.

5. The battery temperature control device according to claim 1 or 2, wherein, The control device is configured to select the first cooling mode when the outside air temperature is higher than or equal to a third set temperature that is higher than the second set temperature.

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