Battery cooling device

Abstract

The present disclosure relates to a battery cooling device. The battery cooling device is mounted on a vehicle, and includes a thermosyphon-type battery cooling circuit, a temperature control device, and an electronic control unit. The electronic control unit, after a circulation stop condition is satisfied, executes vapor phase temperature increasing control that controls the temperature control device to increase the temperature of a vapor phase side in the battery cooling circuit, in a case where circulation of the battery cooling refrigerant has not started and a liquid level of the battery cooling refrigerant is not at a circulation startable level.

Description

Technical Field

[0001] This disclosure relates to a battery cooling device having a thermosiphon-type battery cooling circuit. Background Technology

[0002] Japanese Patent Application Publication No. 2019-057429 discloses a thermosiphon-type equipment temperature control device. This device includes: a heat exchanger for cooling a battery by evaporating refrigerant; a condenser for condensing the refrigerant; and a fluid circulation loop having gas-side piping and liquid-side piping. Furthermore, the device adjusts the heat dissipation capacity of the condenser to minimize the difference between the refrigerant temperature detected by a refrigerant temperature sensor and a predetermined target refrigerant temperature. Summary of the Invention

[0003] When a battery cooling device with a thermosiphon-type battery cooling circuit as described in Japanese Patent Application Publication No. 2019-057429 is installed in a vehicle, the following problem exists: When the vehicle moves from a low ambient temperature environment to a high ambient temperature environment while the battery temperature is low, and the condenser temperature regulation is initiated to cool the battery, the circulation of refrigerant in the battery cooling circuit may stop. As a result, battery cooling may fail, or the start of battery cooling may be delayed.

[0004] This disclosure was made in view of the problems described above, and its object is to enable the rapid initiation of the circulation of the battery cooling refrigerant in a battery cooling device having a thermosiphon-type battery cooling circuit when the circulation stop condition is met.

[0005] The battery cooling device disclosed herein is mounted in a vehicle and includes a thermosiphon-type battery cooling circuit, a temperature control device, and an electronic control unit. Battery coolant is sealed inside the battery cooling circuit. The battery cooling circuit includes one or more coolers, one or more condensers, a vapor passage, and a liquid passage. The temperature control device controls the temperature of at least one of the one or more condensers. The electronic control unit controls the temperature control device.

[0006] One or more coolers cool one or more battery cells by absorbing heat from one or more battery cells, causing the liquid phase of the battery cooling refrigerant to evaporate. One or more condensers are positioned vertically above the one or more coolers to condense the vaporized battery cooling refrigerant from the one or more coolers. Vapor passages connect one or more coolers to one or more condensers, allowing the vaporized battery cooling refrigerant to flow to one or more condensers. Liquid passages connect one or more condensers to one or more coolers, allowing the liquid phase of the battery cooling refrigerant to flow to one or more coolers.

[0007] When one or more battery cells require cooling, the electronic control unit determines, based on the temperatures of the battery cells and the external air temperature, whether a circulation stop condition is met that could potentially halt the circulation of the battery coolant in the battery cooling circuit. Furthermore, if the circulation stop condition is met, but the battery coolant circulation has not yet begun and the coolant level is not at a level suitable for initiating circulation, the electronic control unit executes vapor phase temperature rise control by controlling the temperature control device to raise the coolant level to a level suitable for initiating circulation.

[0008] Alternatively, even if the cycle stop condition is not met, the electronic control unit can perform normal cooling control of the temperature control device to bring the temperature of the battery cooling refrigerant close to a first target refrigerant temperature for cooling one or more battery cells. Then, if the battery cooling refrigerant cycle has not started after the liquid level reaches a level suitable for starting cycle following the execution of vapor phase temperature rise control, preliminary cooling control can be performed before starting battery cooling refrigerant cycle. Preliminary cooling control controls the temperature control device to approach a second target refrigerant temperature, which is set higher than that of normal cooling control, so that one or more condensers are not immersed in the liquid phase of the battery cooling refrigerant.

[0009] Alternatively, if the liquid level is higher than the circulating level during the execution of the initial cooling control, the electronic control unit can execute the vapor phase heating control again.

[0010] The battery cooling device may also include one or more heaters, which are configured on the vapor phase side of the battery cooling circuit. The electronic control unit may then activate one or more heaters during the execution of vapor phase temperature control.

[0011] One or more condensers may include: a first condenser that allows heat exchange between the air conditioning refrigerant flowing through the vehicle air conditioning system or a fluid exchanging heat with the air conditioning refrigerant and the battery cooling refrigerant; and an air-cooled second condenser. The second condenser may then be positioned vertically below the first condenser.

[0012] One or more condensers may also include: a first condenser through which the air conditioning refrigerant flowing through the vehicle's air conditioning system, or a fluid exchanging heat with the air conditioning refrigerant, exchanges heat with the battery cooling refrigerant; and an air-cooled second condenser. The battery cooling circuit may also include a flow path switching valve capable of selecting between a non-bypass flow path state and a bypass flow path state. In the non-bypass flow path state, the vapor-phase battery cooling refrigerant from one or more condensers passes sequentially through the first condenser and the second condenser. In the bypass flow path state, the vapor-phase battery cooling refrigerant from one or more condensers bypasses the first condenser and passes through the second condenser. The electronic control unit may then control the flow path switching valve to select the bypass flow path state during the execution of vapor phase temperature control.

[0013] According to the battery cooling device of this disclosure, after the circulation stop condition is met, vapor phase temperature rise control is performed when the circulation of the battery cooling refrigerant has not started and the liquid level of the battery cooling refrigerant is not at a level at which circulation can begin. This allows the liquid level to be lowered. As a result, compared to the case where normal cooling control is entered without vapor phase temperature rise control under the circulation stop condition, circulation can be started at a earlier timing. Attached Figure Description

[0014] 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, wherein:

[0015] Figure 1 This is a diagram showing the schematic structure of the battery cooling device according to Embodiment 1.

[0016] Figure 2 This is a diagram showing the schematic structure around the first condenser in Embodiment 1.

[0017] Figure 3 This is a diagram showing the state of the cycle without battery cooling of the refrigerant (refrigerant A).

[0018] Figure 4 This is a diagram illustrating the typical cycle state during the execution of normal cooling control.

[0019] Figure 5AIt is a diagram used to illustrate topics related to the refrigerant cycle within a battery cooling circuit.

[0020] Figure 5B It is a diagram used to illustrate topics related to the refrigerant cycle within a battery cooling circuit.

[0021] Figure 6 This is a flowchart illustrating the process related to the control of the battery cooling device in Embodiment 1.

[0022] Figure 7 This is a diagram used to illustrate the general outline of vapor phase temperature control.

[0023] Figure 8 This is a diagram used to illustrate the overview of pre-cooling control.

[0024] Figure 9 It shows the direction Figure 1 The diagram shows an example of a battery cooling circuit with a heater.

[0025] Figure 10 This is a diagram showing the schematic structure of the battery cooling device according to Embodiment 2.

[0026] Figure 11 This is a flowchart illustrating the process related to the flow path control around the first and second condensers in Embodiment 2. Detailed Implementation

[0027] In the embodiments described below, common elements in all figures are given the same symbols, and descriptions that are repeated briefly are omitted. Furthermore, when the number, quantity, amount, range, etc., of each element are mentioned in the embodiments shown below, the technical concept of this disclosure is not limited to the mentioned number, unless specifically stated otherwise or clearly determined in principle. Additionally, the structures, steps, etc., described in the embodiments shown below, except where specifically stated otherwise or clearly determined in principle, are not necessarily essential to the technical concept of this disclosure.

[0028] 1. Implementation Method 1

[0029] 1-1. Structure of the battery cooling device

[0030] Figure 1 This is a diagram showing a schematic structure of the battery cooling device 10 according to Embodiment 1. The battery cooling device 10 is mounted in a vehicle. More specifically, a battery pack 1 is mounted in the vehicle. For example, the battery pack 1 contains a plurality of stacked battery cells. However, the number of battery cells contained in the battery pack 1 is not particularly limited, and may be one. The battery pack 1 stores the power supplied to the vehicle's motor.

[0031] During the discharge and charging of battery pack 1, each battery cell generates heat in conjunction with the power supply. Battery cooling device 10 is configured to cool each battery cell within battery pack 1. Figure 1 In the middle, as an example, it means as in Figure 1 2. Four battery stacks consisting of multiple battery cells stacked in the depth direction of the paper.

[0032] The battery cooling device 10 transfers heat from the battery cells of each battery stack 2 and dissipates it. Specifically, the battery cooling device 10 includes a thermosiphon-type battery cooling circuit 12 containing refrigerant (working fluid). The battery cooling circuit 12 includes a cooler 14, a condenser 16, a vapor passage 18, and a liquid passage 20. Furthermore, the refrigerant flowing through the battery cooling circuit 12 is equivalent to an example of the "battery cooling refrigerant" of this disclosure. In the following description, to distinguish it from the "air conditioning refrigerant" used in the vehicle air conditioning device 24 described later, the battery cooling refrigerant will be referred to as "refrigerant A," and the air conditioning refrigerant will be referred to as "refrigerant B."

[0033] Vapor passage 18 connects each cooler 14 to the condenser 16. Liquid passage 20 connects the condenser 16 to each cooler 14. That is, vapor passage 18 and liquid passage 20 are formed in a ring as refrigerant passages. The battery cooling circuit 12 is a heat pipe through which heat is transferred by the evaporation and condensation of refrigerant A. It is a ring-shaped thermosiphon that separates the vapor passage 18 through which refrigerant A (vapor phase refrigerant) flows and the liquid passage 20 through which refrigerant A (liquid phase refrigerant) flows.

[0034] As the refrigerant A circulating in the battery cooling circuit 12, a Freon series refrigerant (e.g., R134a or R1234yf) that is used in vapor compression refrigeration cycles can be used, for example. Alternatively, other refrigerants such as carbon dioxide or antifreeze can also be used as refrigerant A.

[0035] like Figure 1 As shown, cooler 14, as an example, is configured between a pair of battery stacks 2. Figure 1 In this example, two pairs of battery stacks 2 are shown, so the number of coolers 14 is two. However, the number of coolers can vary depending on the configuration of the battery cells within the battery pack 1, and can be one or more. Each cooler 14 is in contact with the side of each of the two adjacent battery stacks 2, for example, via a thermally conductive material 22. More specifically, the cooler 14 is formed to extend in the stacking direction of the battery cells (the depth direction in the paper) and to contact the battery cells contained in each battery stack 2 via the thermally conductive material 22.

[0036] Inside the cooler 14, a refrigerant passage is formed that functions as part of the refrigerant passage in the battery cooling circuit 12. Liquid refrigerant is supplied to the cooler 14 from the liquid passage 20. The cooler 14 absorbs heat emitted by the battery stack 2 (multiple battery cells) and causes the liquid refrigerant to evaporate, thereby cooling each battery cell.

[0037] like Figure 1 As shown, the inlet (liquid inlet) 14a of the liquid refrigerant to the cooler 14 is located vertically downwards. The outlet (vapor outlet) 14b of the vapor refrigerant from the cooler 14 is located vertically upwards. Furthermore, in a direction orthogonal to the vertical direction (depth direction of the paper), the liquid inlet 14a and the vapor outlet 14b are arranged on opposite sides. Thus, the liquid refrigerant supplied to the cooler 14 receives heat from each battery cell and vaporizes (boils) (boiling cooling). The vaporized refrigerant (vapor) inside the cooler 14 moves vertically upwards and flows out from the vapor outlet 14b into the vapor passage 18.

[0038] Vapor passage 18 is a refrigerant passage through which refrigerant A (vapor refrigerant) vaporized in cooler 14 flows to condenser 16. That is, the heat generated in each cell is transferred to condenser 16 by vapor refrigerant. More specifically, regarding vapor passage 18, after the vapor refrigerants from each cooler 14 merge, it extends upwards in the vertical direction and connects to vapor inlet 16a of condenser 16.

[0039] A refrigerant passage is formed inside the condenser 16, functioning as part of the refrigerant passage in the battery cooling circuit 12. The condenser 16 cools and condenses the vaporized refrigerant that has vaporized in the cooler 14. That is, the heat transferred from the cooler 14 is dissipated in the condenser 16.

[0040] The condenser 16 is positioned vertically above the cooler 14. The specific structure of the condenser 16, used for condensing the vapor-phase refrigerant, is not particularly limited. As an example, the condenser 16 is a liquid-cooled condenser utilizing the vehicle air conditioning unit 24 for air conditioning the vehicle interior.

[0041] Figure 2 This is a diagram showing a schematic structure around the condenser 16 in Embodiment 1. Figure 2 In the illustrated structural example, a vehicle air conditioning unit 24 and a fluid circulation loop 26 are used. The vehicle air conditioning unit 24 is, for example, a heat pump type cooling and heating device. The fluid circulation loop 26 is a loop that circulates a fluid (e.g., long-life coolant (LLC)) that exchanges heat with the refrigerant A flowing through the condenser 16, and includes a pump 28 (e.g., electric) for circulating the LLC.

[0042] More specifically, the vehicle air conditioning unit 24 has a heat exchange section HE1 for the air blown into the vehicle interior and the refrigerant B (air conditioning refrigerant), and a heat exchange section HE2 capable of exchanging heat between the refrigerant B and LLC. Figure 2 In this diagram, only the heat exchange section HE2 is shown as the vehicle air conditioning unit 24. The heat exchange section HE2 is disposed on the fluid circulation loop 26. Figure 2 The structure shown controls the vehicle air conditioning unit 24 to allow refrigerant B to flow to the heat exchange section HE2 and operate in a cooling mode, while also activating the pump 28 to exchange heat between the refrigerant B and the LLC, thereby enabling the refrigerant B to lower the temperature of the LLC. Alternatively, the vehicle air conditioning unit 24 can be controlled to allow refrigerant B to flow to the heat exchange section HE2 and operate in a heating mode, while also activating the pump 28 to exchange heat between the refrigerant B and the LLC, thereby enabling the refrigerant B to raise the temperature of the LLC.

[0043] As mentioned above, according to Figure 2 The structure shown allows the temperature of the LLC to be adjusted using the vehicle air conditioning system 24. Furthermore, the condenser 16 is configured to allow heat exchange between the refrigerant A and the LLC. Therefore, by adjusting the temperature of the LLC (temperature regulation), the refrigerant A flowing through the condenser 16 can be cooled or heated. In other words, by operating the pump 28 to circulate the LLC within the fluid circulation loop 26 at a desired rate and controlling the various components of the vehicle air conditioning system 24 (e.g., expansion valve, flow path switching valve, and compressor), the heat dissipation capacity of the condenser 16 can be adjusted. Furthermore, in Figure 2 In the structural example shown, the combination of the vehicle air conditioning device 24 and the fluid circulation loop 26 is equivalent to an example of the "temperature control device for controlling the temperature of at least one of one or more condensers" of this disclosure.

[0044] Furthermore, the structure of the condenser 16 is not limited to the example using the LLC described above. That is, the condenser 16 may also be configured to allow the refrigerant B used in the vehicle air conditioning unit 24 to directly exchange heat with the refrigerant A without passing through an LLC. In this example, the vehicle air conditioning unit 24 is another example of a "temperature control device". Additionally, the condenser 16 may not be liquid-cooled, but rather air-cooled, for example. That is, the condenser 16 may also be configured as an air-cooled radiator to allow heat exchange between external gas and refrigerant A. Furthermore, in the air-cooled example, for heat exchange between external gas and refrigerant A, the vehicle's running air may or may not be used, or a blower fan (e.g., electric) may be used in conjunction with the running air to forcibly supply external gas to the condenser 16. In the air-cooled example, the radiator accompanying the blower fan is another example of a "temperature control device".

[0045] Return to Figure 1 The liquid passage 20 is connected to the liquid outlet 16b of the condenser 16. The liquid passage 20 is a refrigerant passage that allows the liquid refrigerant liquefied in the condenser 16 to flow to the coolers 14. The liquid passage 20 extends downwards in the vertical direction and then horizontally before connecting to the liquid inlet 14a of each cooler 14. Thus, the liquid refrigerant flowing out of the condenser 16 moves to the downward side in the vertical direction due to its own weight.

[0046] According to the battery cooling circuit 12 described above, when the temperature of the battery cells in each battery stack 2 increases while the vapor phase refrigerant is being cooled in the condenser 16, the refrigerant circulates naturally, thereby enabling continuous cooling of the battery cells.

[0047] In addition, the battery cooling device 10 includes an electronic control unit (ECU) 30. The ECU 30 is a computer that performs various processes related to the battery cooling device 10. Specifically, the processes performed by the ECU 30 include those related to the control of the vehicle air conditioning system 24 for temperature regulation of the condenser 16 and the fluid circulation loop 26. The ECU 30 includes a processor 30a and a storage device 30b. The processor 30a reads and executes programs stored in the storage device 30b. Thus, various processes performed by the processor 30a are realized.

[0048] ECU 30 receives sensor signals from various sensors used for the aforementioned processes. These various sensor types include, for example, refrigerant temperature sensors 32 and 34, battery temperature sensor 36, LLC temperature sensor 38, and external air temperature sensor 40. Refrigerant temperature sensor 32 detects the temperature of the liquid refrigerant outside the battery pack 1 (hereinafter also simply referred to as "refrigerant temperature T").LQ 1) and installed in the liquid passage 20. The refrigerant temperature sensor 34 is used to detect the temperature of the liquid refrigerant in the battery pack 1 (hereinafter also referred to as "refrigerant temperature T"). LQ 2”)) and installed in the liquid passage 20. The battery temperature sensor 36 detects the temperature of the battery cell (hereinafter also referred to as "battery temperature T"). B As an example, battery temperature sensors 36 are installed in a predetermined number of battery cells within each of the battery cells contained in the battery stack 2. LLC temperature sensors 38 are used to detect the temperature T of LLC flowing into the condenser 16. LLC The fluid circulation loop 26 is installed. The external temperature sensor 40 is installed in the vehicle to detect the external temperature T. A .

[0049] 1-2. Control of battery cooling device

[0050] Next, the control of the battery cooling device 10 for temperature regulation of the condenser 16 will be described, more specifically, the control of the "temperature control device (vehicle air conditioning device 24 and fluid circulation loop 26)".

[0051] 1-2-1. Typical cooling control

[0052] "Normal cooling control" is equivalent to the basic control of the battery cooling device 10 performed for cooling the batteries (each battery cell of the battery stack 2).

[0053] Figure 3 This diagram illustrates the state of the cycle without refrigerant A. A suitable amount of refrigerant A is sealed within the battery cooling circuit 12. This suitable amount is set, for example, in a manner that prevents the liquid level from drying out when the vehicle is tilted or when acceleration is applied to the vehicle during acceleration, deceleration, or cornering. Within the battery cooling circuit 12 where refrigerant A is sealed, refrigerant A is in a saturated state.

[0054] Figure 4 This is a diagram illustrating the typical cycle state during the execution of normal cooling control. The refrigerant A in the battery cooling circuit 12 is circulated by the vaporization (boiling) of refrigerant A in cooler 14 and the condensation of refrigerant A in condenser 16.

[0055] More specifically, when cooling of condenser 16 is initiated via temperature regulation by LLC, condensation of the vapor-phase refrigerant within condenser 16 occurs. The result is as follows: Figure 4As shown, a liquid column is formed at the portion extending vertically in the liquid passage 20. The weight of the refrigerant A in this liquid column becomes the driving force for the refrigerant A to flow from the condenser 16 side to the cooler 14 side. On the other hand, on the cooler 14 side, when each cell heats up and a temperature difference is generated between the cell and the liquid refrigerant, the liquid refrigerant boils within the cooler 14. The resulting vaporized refrigerant flows to the condenser 16 through the vapor passage 18. Furthermore, within the condenser 16, refrigerant A liquefies and flows out of the condenser 16, accompanied by a pressure drop in the vaporized refrigerant within the vapor passage 18. This promotes the boiling of refrigerant A within the cooler 14.

[0056] In order to maintain Figure 4 The battery is cooled in a normal cyclic state as shown, with ECU 30 performing normal cooling control. In this normal cooling control, ECU 30 keeps the temperature of refrigerant A (e.g., the temperature T of refrigerant A outside the battery pack 1 detected by refrigerant temperature sensor 32) constant. LQ 1) The vehicle air conditioning system 24 and the fluid circulation loop 26 are controlled in a manner close to the target refrigerant temperature T0. More specifically, for example, the ECU 30 activates the pump 28 to circulate the LLC and bring the refrigerant temperature T0 up to approximately the target refrigerant temperature. LQ 1. The throttling opening of the expansion valve (not shown) of the vehicle air conditioning device 24 is controlled in a manner close to the target refrigerant temperature T0.

[0057] The target refrigerant temperature T0 is calculated, for example, based on the value of the battery heat generation Q. The battery heat generation Q is the total heat generation of the multiple battery cells housed within the battery pack 1. The battery heat generation Q can be calculated, for example, based on the output current value of the battery pack 1 obtained using a current sensor (not shown) and the resistance values ​​of the multiple battery cells housed within the battery pack 1. Furthermore, the target refrigerant temperature T0 corresponds to an example of the "first target refrigerant temperature" of this disclosure.

[0058] 1-2-2. Topics related to refrigerant cycles

[0059] Figure 5A Figures B and C are used to illustrate issues related to the refrigerant circulation within the battery cooling circuit 12. More specifically, Figure 5A The state of the battery cooling circuit 12 is shown under the condition that the "cycle stop condition" may cause the refrigerant A to stop. Figure 5B It shows from Figure 5A The state shown is the state of the battery cooling circuit 12 when the refrigerant A in the condenser 16 is being cooled.

[0060] First, the "cycle-stopping condition" referred to here is when the battery temperature T is lowered due to the battery stack 2 not generating heat. B This condition can be met when a vehicle moves from a low external temperature environment to a high external temperature environment. For example, such a cyclical stopping condition can be met when a vehicle in a high external temperature region moves from a temperature-controlled garage outside.

[0061] Under the condition that the loop stops, such as Figure 5A As shown, refrigerant A vaporizes at the location of the liquid passage 20 near the battery stack 2. The battery cooling circuit 12 is saturated. Therefore, along with the vaporization of refrigerant A at the aforementioned location, liquid refrigerant remains in the cooler 14 or in the vertical portion of the liquid passage 20. Furthermore, in the state where the cooling of refrigerant A in the condenser 16 and the heating of the battery stack 2 have not yet begun, it is possible to obtain... Figure 5A The state shown.

[0062] When the battery cooling circuit 12 is in Figure 5A When the state shown is such that cooling of the battery begins based on refrigerant A for normal cooling control, the interior of the battery cooling circuit 12 becomes as follows: Figure 5B The state shown indicates that the cooler 14 is in a liquid-immersed state, and the battery temperature T is... B The pressure is low, so refrigerant A in cooler 14 does not begin to boil. Then, without supplying vapor-phase refrigerant from cooler 14 to condenser 16, cooling of refrigerant A in condenser 16 proceeds, so the liquid column height in liquid passage 20 increases, and condenser 16 becomes liquid-immersed. Furthermore, when condenser 16 is liquid-immersed, a pressure drop in vapor-phase refrigerant in vapor passage 18, which accompanies the outflow of condensed refrigerant A from condenser 16, does not occur or is difficult to occur. As a result, even if the battery stack 2 begins to heat up, boiling of refrigerant A in cooler 14 is not easily initiated, so the liquid-immersed state of cooler 14 is not eliminated or is difficult to eliminate. Therefore, refrigerant A circulation does not occur.

[0063] When it becomes as described above Figure 5B In the state shown, although temperature regulation of condenser 16 begins, refrigerant A circulation does not begin. Alternatively, the start of circulation is delayed (in other words, at battery temperature T...). B (Cycling does not begin until the temperature reaches a level comparable to the outside temperature). The cooling of battery stack 2 is delayed. Furthermore, when condenser 16 is immersed in refrigerant A, the heat transfer area between the vapor-phase refrigerant and LLC within condenser 16 decreases. This results in a reduction in the amount of refrigerant A condensed, making refrigerant A more difficult to cycle.

[0064] When a cycle stop occurs as a result of satisfying the above-mentioned "cycle stop condition", cooling of battery stack 2 cannot be performed, or the start of cooling of battery stack 2 is delayed.

[0065] 1-2-3. Control of the battery cooling device under cycle-stop conditions

[0066] In view of the above-mentioned issues, in this embodiment, after the circulation stop condition is met, the ECU 30 performs "vapor phase temperature rise control" to bring the liquid level to the level where circulation of refrigerant A can begin, provided that the circulation of refrigerant A has not started and the liquid level of refrigerant A is not at the level where circulation can begin. Vapor phase temperature rise control raises the temperature of the vapor phase side in the battery cooling circuit 12 by controlling the vehicle air conditioning device 24 and the fluid circulation loop 26.

[0067] Additionally, if the refrigerant A circulation has not started after the liquid level reaches a level suitable for starting circulation via vapor phase temperature rise control, ECU30 performs "preliminary cooling control" until the refrigerant A circulation begins. Preliminary cooling control controls the refrigerant temperature T0 in a manner close to a target refrigerant temperature T0' that is set higher than the target refrigerant temperature T0 during the aforementioned normal cooling control. LQ 1. This ensures that the condenser 16 is not immersed in liquid refrigerant. Furthermore, the target refrigerant temperature T0' corresponds to an example of the "second target refrigerant temperature" of this disclosure.

[0068] Furthermore, when the liquid level is about to rise during the execution of the initial cooling control, the ECU30 will execute the vapor phase temperature rise control again.

[0069] Figure 6 This is a flowchart illustrating the process related to the control of the battery cooling device 10 in Embodiment 1. The processes described in this flowchart are repeatedly executed when a battery cooling request is requested during the vehicle system startup process.

[0070] exist Figure 6 In step S100, ECU30 first determines the battery temperature T based on the battery temperature T. B and external temperature T A This is used to determine whether the cycle termination condition is met. Specifically, the existence or absence of the cycle termination condition is determined, for example, by determining the battery temperature T. B With external temperature T A Threshold TH TA The mapping of relationships (illustration omitted) is pre-stored in the storage device 30b of the ECU 30. Based on this mapping, the threshold TH... TA For example, battery temperature T B The setting is such that the lower the value, the smaller the result.

[0071] Furthermore, in this step S100, the ECU30 acquires the current battery temperature T detected by the battery temperature sensor 36. B The corresponding threshold TH TA Then, ECU30 uses the current outside temperature T detected by outside temperature sensor 40. A To obtain the threshold TH TA Under the above circumstances, the loop termination condition is determined to be met.

[0072] Furthermore, the presence or absence of the cycle termination condition can also be related to the external temperature T. A Threshold TH TA Together, the same method is used to achieve the same temperature as the battery (T). B The refrigerant temperature T is set according to the corresponding value. LQ Threshold TH of 1 TLQ This is used to make the determination. Specifically, ECU30 can, for example, determine the current external temperature T. A Threshold TH TA The above, and the current refrigerant temperature T detected by refrigerant temperature sensor 32 LQ 1 is the threshold TH TLQ Under the above conditions, the cycle termination condition is determined to be met. Additionally, based on the battery temperature T... B To determine the threshold TH TLQ In the mapping, with threshold TH TA Similarly, the threshold TH TLQ For example, the battery temperature T can also be used. B The threshold TH is set to be smaller the lower it is. TLQ It can be compared with the threshold TH TA They can be the same, or they can be different.

[0073] If the cycle stop condition is not met in step S100, the process proceeds to step S102. In step S102, the ECU 30 performs the aforementioned normal cooling control. On the other hand, if the cycle stop condition is met, the process proceeds to step S104.

[0074] In step S104, the ECU 30 determines whether a fast charging request exists. For example, the ECU 30 determines that a fast charging request has been issued when it detects that the power plug is connected to the fast charging port provided in the vehicle. During fast charging, the battery stack 2 generates more heat compared to normal charging. Therefore, it is required to start cooling earlier after charging begins. Thus, in step S104, it is determined whether the condition for a request to start battery cooling earlier is met. Therefore, in step S104, it is also possible to determine whether a high-load driving request for the vehicle exists, either without a fast charging request or together with a fast charging request, for example, based on the accelerator opening.

[0075] If no rapid charging request is received in step S104, the process proceeds to step S102, where normal cooling control is performed. Conversely, if a rapid charging request is received, the process proceeds to step S106.

[0076] In step S106, the ECU 30 determines whether the circulation of refrigerant A within the battery cooling circuit 12 has stopped (in other words, whether the circulation has not started). This determination can be made, for example, based on the LLC temperature T detected by the LLC temperature sensor 38. LLC and refrigerant temperature T LQ 1. Specifically, under proper refrigerant A circulation, the refrigerant temperature T LQ 1 (i.e., the refrigerant temperature at the lower vertical portion of the liquid passage 20) relative to the LLC temperature T flowing into the condenser 16. LLC This is a greater increase than the corresponding increase in battery heat generation Q. In contrast, if the circulation of refrigerant A actually stops, the refrigerant temperature T... LQ 1 becomes related to the external temperature T A A comparable value. In other words, LLC temperature T LLC Relative to refrigerant temperature T LQ The difference of 1 has increased.

[0077] Therefore, in step S106, ECU30 determines the LLC temperature T. LLC Relative to refrigerant temperature T LQ Is the difference between 1 and 2 a predetermined threshold? If the difference is above the threshold, the ECU30 determines that the circulation of refrigerant A has stopped (circulation has not started) (step S106; Yes). On the other hand, if the difference is less than the threshold, the ECU30 determines that the circulation of refrigerant A has not stopped (circulation has started) (step S106; No).

[0078] Furthermore, in step S106, the following determination may also be performed additionally. That is, if, during the execution of normal cooling control based on the process in step S102, the determination results of steps S100 and S104 are affirmative, and the process proceeds to step S106, the ECU 30 determines whether there is a malfunction due to improper circulation by performing the circulation as follows: That is, the ECU 30 may also determine the LLC temperature T when a predetermined time has elapsed since the start of the refrigerant A circulation. LLC Relative to refrigerant temperature T LQ Is the difference of 1 greater than or equal to the aforementioned threshold? Then, if the difference is greater than or equal to the threshold after a predetermined time has elapsed, the ECU30 may determine that a poor cycle has occurred.

[0079] If it is determined in step S106 that no cycle stop / cycle malfunction has occurred, the process proceeds to step S102, where normal cooling control is performed. On the other hand, if it is determined that a cycle stop / cycle malfunction has occurred, the process proceeds to step S108.

[0080] In step S108, the ECU 30 determines whether the conditions for starting a cycle are met (in other words, whether the liquid level of refrigerant A is at a level suitable for starting a cycle). Specifically, for this determination, the ECU 30 calculates the estimated liquid level L1 in the cooler 14 and the estimated liquid level L2 of the liquid column in the liquid passage 20. Then, if the cooler 14 and the condenser 16 are not in a liquid-immersed state according to the calculated estimated liquid levels L1 and L2, the ECU 30 determines that the conditions for starting a cycle are met. On the other hand, if either or both of the cooler 14 and the condenser 16 are in a liquid-immersed state according to the calculated estimated liquid levels L1 and L2, the ECU 30 determines that the conditions for starting a cycle are not met. Thus, in step S108, the conditions for starting a cycle of refrigerant A are determined based on the estimated liquid levels L1 and L2 of refrigerant A.

[0081] The estimated liquid level L1 in the cooler 14 can be determined, for example, based on the refrigerant temperature T in the battery pack 1. LQ 2 and battery temperature T B The calculation is based on the relationship. Specifically, under proper refrigerant A circulation, the refrigerant flowing through the low refrigerant temperature T cooled by condenser 16... LQ The refrigerant is A, so the battery temperature is T. B With refrigerant temperature T LQ The difference between 2 and 3 decreases. In contrast, without circulation, the refrigerant temperature T... LQ 2. Battery temperature T BThe temperature is high, so it can be determined that the cooler 14 is in a liquid-immersed state (i.e., the liquid level is presumed to be high). Therefore, the storage device 30b of the ECU 30 stores the information that determines the refrigerant temperature T. LQ 2 and battery temperature T B Mapping to the predicted liquid level L1 (illustration omitted). The predicted liquid level L1 can be calculated, for example, based on such a mapping.

[0082] Furthermore, the estimated liquid level L2 can be determined using the same approach as the estimated liquid level L1, for example, based on the refrigerant temperature T outside battery pack 1. LQ 1 and LLC temperature T LLC The calculation is based on the relationship between the refrigerant temperature T and the refrigerant temperature T. Specifically, the storage device 30b of the ECU 30 stores the information that determines the refrigerant temperature T. LQ 1 and LLC temperature T LLC A mapping relating to the estimated liquid level L2 (illustration omitted). The estimated liquid level L2 can be calculated, for example, based on such a mapping. Alternatively, instead of using such an example of estimated liquid levels L1 and L2, the liquid level within the cooler 14 and the liquid level on the liquid column side used for the determination in step S108 can be obtained, for example, using a liquid level sensor.

[0083] If the conditions for starting a cycle are not met in step S108, the process proceeds to step S110. In step S110, ECU30 performs the aforementioned vapor phase temperature rise control. Figure 7 This is a diagram illustrating the outline of vapor phase temperature rise control. Vapor phase temperature rise control is performed to heat the vapor phase side of the battery cooling circuit 12 to reduce the overall liquid level of the battery cooling circuit 12 (i.e., the liquid level inside the cooler 14 and the liquid level on the liquid column side).

[0084] In order to heat the vapor phase side for the aforementioned purpose, Figure 7 In the example shown, the condenser 16 is heated using temperature regulation. More specifically, the ECU 30 operates the pump 28 and controls the vehicle's air conditioning system 24 to adjust the temperature T of the LLC flowing in the condenser 16. LLC The temperature rises. As a result, condenser 16 is heated. The heat transferred from LLC to condenser 16 is then transferred to vapor passage 18. Consequently, the vapor-phase refrigerant within vapor passage 18 is heated. Additionally, the heat transferred to condenser 16 is also transferred to the portion of liquid passage 20 near condenser 16 (i.e., the portion extending vertically), where the liquid-phase refrigerant is heated. As a result, according to vapor-phase temperature rise control, the liquid level within cooler 14 and the liquid level on the liquid column side decrease.

[0085] When the liquid level in the cooler 14 and the liquid level on the liquid column side decrease due to the execution of the above-mentioned vapor phase temperature rise control, the determination result of the subsequent step S108 becomes positive. That is, the conditions for starting the cycle are met. As a result, the process proceeds to step S112.

[0086] In step S112, ECU30 performs the aforementioned preliminary cooling control. If the circulation of refrigerant A begins after the conditions for starting circulation are met in step S108, the determination result of the subsequent step S106 becomes negative, and the process switches to normal cooling control. In other words, the preliminary cooling control is performed from the time the liquid level reaches the level for starting circulation due to the execution of vapor phase temperature rise control until the circulation of refrigerant A begins.

[0087] Figure 8 This diagram illustrates the general outline of the pre-cooling control. When cooling of refrigerant A based on normal cooling control begins immediately after the conditions for starting the cycle are met, liquid immersion may occur in the condenser 16. Therefore, the target refrigerant temperature T0' used in the pre-cooling control is set higher than the target refrigerant temperature T0 in normal cooling control to prevent the condenser 16 from being liquid-phase refrigerant immersed. More specifically, the target refrigerant temperature T0' is determined in advance through experiments, etc., such that the liquid level of the liquid column does not exceed the lower surface of the condenser 16 in the vertical direction and is as close as possible to that lower surface. Then, the refrigerant temperature T is controlled in a manner close to such a target refrigerant temperature T0'. LQ 1.

[0088] In addition, according to Figure 6 The flowchart shown illustrates a process where, assuming the cooling of refrigerant A by condenser 16 is ahead of the expected cooling rate during the execution of the pre-cooling control, and as a result, the liquid level rises above the level at which circulation can begin, the determination result in step S108 becomes negative. In this case, vapor phase temperature rise control is executed again in step S110. Then, when the liquid level drops again due to the execution of vapor phase temperature rise control, and the conditions for starting circulation are met again, pre-cooling control is executed again. Thus, according to the process described in this flowchart, it is possible to prevent condenser 16 from being in a liquid-immersed state until the circulation of refrigerant A begins (i.e., from the time the process enters step S108 until the determination result in step S106 becomes negative), and to control the liquid level in a manner that strives to maintain the liquid column level as high as possible.

[0089] 1-3. Effects

[0090] As explained above, according to the battery cooling device 10 of Embodiment 1, after the cycle stop condition is met, vapor phase temperature rise control is performed when the circulation of refrigerant A has not started and the liquid level of refrigerant A is not at a level where circulation can begin. This allows the liquid level to be lowered, eliminating liquid immersion in the condenser 16 and cooler 14. As a result, compared to the case where normal cooling control is entered without vapor phase temperature rise control under the cycle stop condition, circulation can begin at a earlier timing.

[0091] Furthermore, according to the battery cooling device 10, if the refrigerant A circulation has not started after the liquid level reaches a level suitable for starting circulation due to the execution of vapor phase temperature rise control, a preliminary cooling control using a target refrigerant temperature T0' higher than the target refrigerant temperature T0 during normal cooling control is executed before the refrigerant A circulation begins. Therefore, compared to the case where normal cooling control is immediately initiated after the execution of vapor phase temperature rise control, liquid immersion in the condenser 16 can be suppressed, and the liquid level of the liquid column in the liquid passage 20 can be maintained as high as possible. This increases the weight of the liquid refrigerant in the liquid column portion, promoting a rapid start of refrigerant A circulation.

[0092] Furthermore, according to the battery cooling device 10, even if the liquid level rises again after the start of the preliminary cooling control, the liquid level can be lowered by re-executing the vapor phase temperature rise control. Then, if the cycle does not start when the liquid level drops again, the preliminary cooling control is executed again. In this way, the vapor phase temperature rise control and the preliminary cooling control are repeated as needed, and the cycle will start soon. Moreover, instead of a combination of vapor phase temperature rise control and normal cooling control, a combination of preliminary cooling control and vapor phase temperature rise control is used, which utilizes a target refrigerant temperature T0' that is higher than the target refrigerant temperature T0 of the normal cooling control. As a result, it is possible to attempt to start a rapid cycle of refrigerant A while suppressing liquid immersion in the condenser 16 and maintaining the liquid level as high as possible.

[0093] 1-4. Variations

[0094] To improve the effectiveness of the aforementioned vapor phase temperature control, a heater can be provided on the vapor phase side of the battery cooling circuit 12. Furthermore, the ECU 30 can also activate this heater during the execution of the vapor phase temperature control.

[0095] Figure 9 It shows the direction Figure 1 The diagram shows an example of a battery cooling circuit 12 equipped with a heater. Figure 9 The battery cooling device 50 shown differs from the battery cooling device 10 of Embodiment 1 in that it additionally includes a heater 52.

[0096] Specifically, the heater 52 is positioned in the vapor passage 18 near the cooler 14. By positioning the heater 52 at such a location, the liquid level within the cooler 14 can be effectively reduced during the execution of vapor phase temperature control. Thus, the heater 52, which assists in heating the vapor phase, improves the effectiveness of vapor phase temperature control. This allows the refrigerant A to begin circulating earlier.

[0097] Here, the range of objects to be installed with the heater (using...) Figure 9 The area enclosed by the dotted line in the diagram is not limited to the example of heater 52, but can be located anywhere on the vapor phase side of the battery cooling circuit 12. Specifically, the heater can also be located in the upper vertical direction within the vapor passage 18, condenser 16, cooler 14, and in the liquid passage 20 near the condenser 16 (the portion extending vertically). More specifically, the range of objects to which such heaters are installed (that is, objects heated by vapor phase temperature control) can be said to be equivalent to the state without refrigerant circulation (see [reference]). Figure 3 The part located on the vapor phase side. Additionally, multiple heaters can be installed. Furthermore, in the state without refrigerant circulation (see...). Figure 3 The portion of the liquid refrigerant located at the bottom (i.e., the portion of the liquid passage 20 extending horizontally (left-right direction on the paper) on the lower side in the vertical direction), and the middle and lower portions in the vertical direction within the cooler 14, are excluded from the area heated by the heater. This is because when the liquid refrigerant vaporizes by heating such liquid-side portions, the overall liquid level of the battery cooling circuit 12 system rises, promoting the cessation of circulation.

[0098] Additionally, at battery temperature T B The cycle stop condition described above is met under low conditions. Therefore, in the example where the heater is placed in the upper part of the steam passage 18 or the cooler 14, the heater can serve both as an auxiliary function to raise the temperature of the vapor phase and as a preheating function for the battery.

[0099] Furthermore, the battery cooling circuit 12 of Embodiment 1 can also be equipped with a heat-insulating structure to make it difficult to meet the above-mentioned cycle start conditions. Specifically, in order to prevent the liquid refrigerant from being heated by the high external temperature, the outer wall surface of the portion of the liquid passage 20 that is excluded from the range of heater installation (i.e., the portion of the liquid passage 20 extending horizontally (left-right direction on the paper) on the lower side in the vertical direction) can be equipped with a heat-insulating structure. For example, this outer wall surface can be covered with a heat-insulating material. In addition, such a heat-insulating structure is not required for the range of heater installation. This is because the circulation of refrigerant A is facilitated by heating with high-temperature external gas.

[0100] In addition, Figure 6 In the flowchart shown, in step S102, it is determined whether there is a rapid charging request. Because of this step S102, conditions requiring earlier battery cooling are determined (selected), and countermeasures utilizing vapor phase temperature rise control and advance cooling control can be implemented.

[0101] 2. Implementation Method 2

[0102] Figure 10 This is a diagram showing a schematic structure of the battery cooling device 60 according to Embodiment 2. The battery cooling circuit 62 of this battery cooling device 60 differs from the battery cooling circuit 12 of Embodiment 1 in the following aspects.

[0103] Specifically, the battery cooling circuit 62 includes a liquid-cooled condenser 16 and an air-cooled condenser 64. That is, the condenser 64 is configured to exchange heat between the refrigerant A (battery cooling refrigerant) and the external gas. For this heat exchange, the condenser 64 can be configured to utilize the vehicle's running air, or it can be configured not to utilize running air, or it can utilize not only running air but also a blower fan (e.g., electric) not shown in the figure. Furthermore, condensers 16 and 64 correspond to examples of the "first condenser" and "second condenser" of this disclosure, respectively.

[0104] In addition, such as Figure 10 As shown, the air-cooled condenser 64 is positioned above the condenser 14 in the vertical direction and below the condenser 16 in the vertical direction (more specifically, directly below the condenser 16).

[0105] Furthermore, such as Figure 10 As shown, the battery cooling circuit 62 includes a vapor passage 66 and a liquid passage 68. The vapor passage 66 branches off from the condenser 16 and 64 to the vapor inlets 16a and 64a, respectively. The liquid passage 68 includes a portion 68a connecting the liquid outlet 16b to the liquid outlet 64b and a portion 68b connecting the liquid outlet 64b to each cooler 14.

[0106] Furthermore, the battery cooling circuit 62 is configured to allow selection of a "non-bypass flow path state" where the vapor-phase refrigerant from the cooler 14 sequentially passes through the condenser 16 and condenser 64, and a "bypass flow path state" where the vapor-phase refrigerant bypasses the condenser 16 and passes through the condenser 64. To achieve this function, the battery cooling circuit 62, as an example, includes a flow path switching valve 70 for opening and closing the branch passage 66a on the condenser 16 side and a flow path switching valve 72 for opening and closing the branch passage 66b on the condenser 64 side. With this configuration, the non-bypass flow path state can be obtained by opening the flow path switching valve 70 and closing the flow path switching valve 72. Figure 10The non-bypass flow path state is shown. Then, by closing the flow path switching valve 70 and opening the flow path switching valve 72, the bypass flow path state can be obtained.

[0107] Figure 11 This is a flowchart illustrating the process related to the flow path control around the condenser 16 and 64 in Embodiment 2. The process described in this flowchart is the same as described above. Figure 6 The processes shown in the flowchart are executed in parallel.

[0108] exist Figure 11 In step S200, ECU30 first determines whether it is in the process of executing vapor phase temperature rise control. If it is not in the process of executing vapor phase temperature rise control, the process proceeds to step S202. In step S202, ECU30 opens the flow path switching valve 70 and closes the flow path switching valve 72 in a non-bypass flow path selection mode.

[0109] On the other hand, if it is determined in step S200 that the process is in the execution of vapor phase temperature rise control, the process proceeds to step S204. In step S204, ECU30 closes the flow path switching valve 70 and opens the flow path switching valve 72 in a manner that selects the bypass flow path state.

[0110] As explained above, in the battery cooling circuit 62 of Embodiment 2, the air-cooled condenser 64 is positioned vertically below the liquid-cooled condenser 16. In the thermosiphon battery cooling circuit 62, a height difference needs to be maintained between the cooler 14 and the main condenser 16 to ensure smooth circulation of the refrigerant A. Therefore, space is created below the condenser 16. According to the battery cooling circuit 62, the sub-condenser 64 can be configured to effectively utilize this space. Thus, compared to the example where the condenser 16 and condenser 64 are arranged side by side in the horizontal direction, two stages of condensers 16 and 64 can be mounted in a space-saving manner.

[0111] Furthermore, in Embodiment 2, a bypass flow path state is selected during the execution of vapor phase temperature rise control. The condition for executing vapor phase temperature rise control is a high external temperature condition that satisfies the cycle stop condition. Therefore, the refrigerant A can be heated in the condenser 64 using high-temperature external gas. As a result, energy consumption can be suppressed, and vapor phase temperature rise control can be executed. In addition, in the example where the above-described blower fan is provided to promote heat exchange between the external gas and the refrigerant A in the condenser 64, the ECU 30 can also operate the blower fan when the bypass flow path state is selected.

[0112] Furthermore, the option to select the bypass flow path and utilize only the condenser 64 is not limited to the execution of vapor phase temperature rise control. For example, it can also be performed when battery cooling is required under at least one of the following conditions: low heat generation (Q) or low external air temperature. Therefore, cooling can be achieved without the vehicle air conditioning system 24 and the fluid circulation loop 26 operating, even when high cooling capacity is not required, thus enabling energy savings.

[0113] Next, a variation of embodiment 2 will be described. That is, in order to achieve the space-saving effect described above, as long as the condenser 64 is arranged lower in the vertical direction than the condenser 16, it is not necessary to have flow path switching valves 70 and 72. In addition, in order to achieve the energy-saving effect described above, as long as it is configured to allow selection of non-bypass flow path mode and bypass flow path mode, the condenser 64 does not necessarily need to be arranged lower in the vertical direction than the condenser 16.

Claims

1. A battery cooling device mounted on a vehicle, characterized by comprising: a battery cooling circuit of a thermosyphon type, in which a battery cooling refrigerant is enclosed, including one or a plurality of coolers, one or a plurality of condensers, a vapor passage, and a liquid passage; a temperature control device that controls a temperature of at least one of the one or a plurality of condensers; and an electronic control unit that controls the temperature control device, the one or a plurality of coolers vaporize the battery cooling refrigerant in a liquid phase by absorbing heat emitted from one or a plurality of battery cells, thereby cooling the one or a plurality of battery cells, the one or a plurality of condensers are disposed above the one or a plurality of coolers in a vertical direction, condense the battery cooling refrigerant in a vapor phase vaporized by the one or a plurality of coolers, the vapor passage connects between the one or a plurality of coolers and the one or a plurality of condensers, and causes the battery cooling refrigerant in the vapor phase to flow to the one or a plurality of condensers, the liquid passage connects between the one or a plurality of condensers and the one or a plurality of coolers, and causes the battery cooling refrigerant in a liquid phase to flow to the one or a plurality of coolers, the electronic control unit determines whether a circulation stop condition in which circulation of the battery cooling refrigerant in the battery cooling circuit is likely to stop is satisfied, based on a temperature of the one or a plurality of battery cells and an outside air temperature, in a case where a cooling request of the one or a plurality of battery cells is present, and the electronic control unit performs vapor phase temperature increase control that controls the temperature control device to increase a temperature on a vapor phase side in the battery cooling circuit, in a case where the circulation stop condition is satisfied, the liquid level of the battery cooling refrigerant is not at a startable circulation level at which circulation of the battery cooling refrigerant can be started, and circulation of the battery cooling refrigerant has not started.

2. The battery cooling device according to claim 1, characterized in that, in a case where the circulation stop condition is not satisfied, the electronic control unit performs normal cooling control that controls the temperature control device so that a temperature of the battery cooling refrigerant approaches a first target refrigerant temperature, for cooling of the one or a plurality of battery cells, the electronic control unit performs advance cooling control before starting circulation of the battery cooling refrigerant, in a case where the liquid level reaches the startable circulation level by execution of the vapor phase temperature increase control and circulation of the battery cooling refrigerant has not started, and the advance cooling control is control that controls the temperature control device so that the temperature of the battery cooling refrigerant approaches a second target refrigerant temperature that is set to be higher than the first target refrigerant temperature at the time of the normal cooling control, so that the one or a plurality of condensers are not flooded with the battery cooling refrigerant in the liquid phase.

3. The battery cooling device according to claim 2, characterized in that, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ When the liquid level is higher than the startable circulation level during execution of the precooling control, the electronic control unit executes the vapor warming control again.

4. The battery cooling device according to any one of claims 1 to 3, characterized in that the battery cooling device further includes one or more heaters disposed on a vapor phase side of the battery cooling circuit, the electronic control unit operates the one or more heaters during execution of the vapor warming control.

5. The battery cooling device according to any one of claims 1 to 3, characterized in that the one or more condensers include: a first condenser that exchanges heat between the battery cooling refrigerant and air conditioning refrigerant or fluid that exchanges heat with the air conditioning refrigerant flowing through a vehicle air conditioning device mounted on the vehicle; and a second condenser that is an air-cooled condenser, the second condenser is disposed below the first condenser in the vertical direction.

6. The battery cooling device according to any one of claims 1 to 3, characterized in that the one or more condensers include: a first condenser that exchanges heat between the battery cooling refrigerant and air conditioning refrigerant or fluid that exchanges heat with the air conditioning refrigerant flowing through a vehicle air conditioning device mounted on the vehicle; and a second condenser that is an air-cooled condenser, the battery cooling circuit further includes a flow path switching valve that can select a non-bypass flow path state in which the battery cooling refrigerant in a vapor phase that has exited the one or more coolers passes through the first condenser and the second condenser in that order, and a bypass flow path state in which the battery cooling refrigerant in a vapor phase that has exited the one or more coolers passes through the second condenser while bypassing the first condenser, the electronic control unit controls the flow path switching valve so that the bypass flow path state is selected during execution of the vapor warming control.

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