Battery cooling system and method for controlling battery cooling system

Abstract

To provide a battery cooling system suppressing the thermal deterioration of a battery, a control device for a battery cooling system, and a vehicle.SOLUTION: Provided is a battery cooling system 1 including: a heater 11 heating cooling oil for cooling a battery 10; a reserve tank 12 to which the cooling oil flowing out from the heater 11 is supplied and in which gas-liquid separation can be achieved; and a heat exchanger 13 to which the cooling oil flowing out from the reserve tank 12 is supplied and in which heat exchange between the cooling oil and a predetermined cooling liquid is performed. In the battery cooling system, a control unit 21 heats the cooling oil by the heater 11 such that the temperature Tres of the cooling oil reserved in the reserve tank 12 becomes Tp1, and cools the heated cooling oil to Tp2 that is a temperature lower than the Tp1. The cooling oil heated by the heater 11 flows into the battery 10 via the reserve tank 12 and the heat exchanger 13. The moisture of the heated cooling oil evaporates in the reserve tank 12, and the cooling oil is cooled in the heat exchanger 13.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a battery cooling system and a method for controlling a battery cooling system. [Background technology]

[0002] In recent years, a technology has been known in which a heater is provided in a passage through which cooling oil that cools an object to be cooled passes, and when moisture gets mixed into the cooling oil, the cooling oil is heated and the moisture in the cooling oil is evaporated (see, for example, Patent Document 1). An example of the object to be cooled is a medical X-ray tube device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-311170 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology of Patent Document 1, a heater is provided in front of the object to be cooled, so when the control for evaporating the moisture is performed, high-temperature cooling oil reaches the object to be cooled. The object to be cooled may be a medical X-ray tube device or a battery used in an electric vehicle, and if the object to be cooled is something with low heat resistance like a battery, there is a possibility that it may be thermally deteriorated by the high-temperature cooling oil. [Means for solving the problem]

[0005] An object of the present invention is to provide a battery cooling system that suppresses thermal deterioration of a battery, and a control method for the battery cooling system.

[0006] In order to solve the above problems, the battery cooling system of the present invention includes a battery, a heater for heating cooling oil that cools the battery, a reserve tank capable of separating the cooling oil into gas and liquid, a heat exchanger for exchanging heat between the cooling oil and a predetermined fluid, and a control device for controlling the heater and the heat exchanger. In the battery cooling system having the above-mentioned, the cooling oil flows through the heater, the reserve tank, the heat exchanger, and the battery in that order, and the control device controls the heater to heat the cooling oil to a first temperature at which moisture in the cooling oil evaporates, and controls the heat exchanger to cool the cooling oil to a second temperature lower than the first temperature.

[0007] The cooling oil heated by the heater flows into the battery via the reserve tank and heat exchanger. The water in the heated cooling oil evaporates in the reserve tank, and the oil is cooled by the heat exchanger. As a result, cooled cooling oil flows into the battery, and it is possible to prevent the battery from thermally deteriorating due to high temperature cooling oil flowing into the battery when the water evaporates.

[0008] Preferably, the control device changes the second temperature based on the temperature of the battery.

[0009] By changing the second temperature based on the temperature of the battery, it is possible to perform temperature management of the battery while preventing high-temperature cooling oil from flowing into the battery.

[0010] Preferably, when the temperature of the battery is lower than the third temperature, the second temperature is set higher than when the temperature of the battery is higher than the third temperature.

[0011] By setting the second temperature higher when the battery temperature is lower than the third temperature, it is possible to warm up the battery while preventing high-temperature cooling oil from flowing into the battery. In addition, costs can be reduced by using a single heater to both evaporate the moisture in the cooling oil and warm up the battery.

[0012] Preferably, in a vehicle equipped with the above-mentioned battery cooling system and capable of charging the battery externally, at least one of the heater, heat exchanger and control device is supplied with power from the battery, and when the vehicle is being charged, the control device controls the heater to heat the cooling oil to a first temperature at which moisture in the cooling oil evaporates, and the heat exchanger to cool the cooling oil to a second temperature lower than the first temperature.

[0013] By controlling the water evaporation from the cooling oil when the vehicle is being charged, it is possible to suppress an increase in the power consumption of the battery due to the water evaporation control and a decrease in the running performance of the vehicle. Effect of the Invention

[0014] According to the present invention, it is possible to provide a battery cooling system that suppresses thermal deterioration of a battery, and a method for controlling a battery cooling system. [Brief description of the drawings]

[0015] [Figure 1] 1 is a diagram showing a vehicle equipped with a battery cooling system according to an embodiment; [Diagram 2] 1 is a diagram illustrating a schematic configuration of a battery cooling system according to an embodiment. [Diagram 3] 3 is a flowchart showing control for evaporating moisture in the control device of FIG. 2. [Figure 4] FIG. 4 is a diagram showing the relationship between the amount of water evaporation from cooling oil; [Diagram 5] 3 is a flowchart showing a control for warming up the battery in the control device of FIG. 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] <Embodiment> 1 is a diagram that shows a schematic diagram of a vehicle equipped with a battery cooling system 1 according to an embodiment. The battery cooling system 1 is equipped, for example, in an electric vehicle A that includes a motor (not shown) for driving and a battery 10 (not shown) that supplies power to the motor, and the cooling system 1 cools the battery 10. The electric vehicle A refers to, for example, a hybrid electric vehicle (HEV), an electric vehicle (BEV), a fuel cell electric vehicle (FCEV), or the like.

[0017] 2 is a diagram illustrating a schematic configuration of a battery cooling system 1 according to an embodiment. The battery cooling system 1 includes a cooling circuit 50 and a control device 21. The cooling circuit 50 includes a battery 10, a heater 11, a reserve tank 12, a heat exchanger 13, an oil pump, a first flow path 31, a second flow path 32, a third flow path 33, a fourth flow path 34, a fifth flow path 35, a first temperature sensor 41, a second temperature sensor 42, a third temperature sensor 43, and a fourth temperature sensor 44.

[0018] The cooling circuit 50 circulates the cooling oil through the electric pump 14, the first flow path 31, the battery 10, the second flow path 32, the heater 11, the third flow path 33, the reserve tank 12, the fourth flow path 34, the heat exchanger 13, and the fifth flow path 35 in this order. Therefore, the heat exchanger 13 is disposed between the heater 11 and the battery 10. Also, in FIG. 2, the arrows of the first flow path 31, the second flow path 32, the third flow path 33, the fourth flow path 34, and the fifth flow path 35 indicate the direction in which the cooling oil flows. The cooling oil may be a known oil, for example, an oil having high electrical insulation. Specifically, the cooling oil may be a mineral oil, a synthetic oil, a silicone oil, a fluorine oil, or the like.

[0019] The electric pump 14 is driven by power supplied from the battery 10, draws in cooling oil from an intake port, and discharges the cooling oil from an exhaust port. A first flow path 31 is connected to the exhaust port of the electric pump 14. The cooling oil discharged from the electric pump 14 to the first flow path 31 is pumped toward the downstream side of the cooling circuit 50 by the discharge pressure of the electric pump 14. The battery 10 is connected to the downstream side of the first flow path 3120.

[0020] The battery 10 is a power storage device capable of charging electric power, and corresponds to a "battery". The battery 10 is configured to have, for example, a battery case and a battery module (not shown). The battery module is configured, for example, of a lithium ion battery. The battery cells are not particularly limited as long as they are secondary batteries capable of charging and discharging electric power, and may be, for example, nickel-metal hydride batteries. Here, the downstream side of the first flow path 31 is connected to the inlet of the battery case of the battery 10. The cooling oil flows into the inside of the battery case from the first flow path 31, and when the temperature of the flowing cooling oil is lower than the temperature of the battery module, the heat of the battery module is transferred to the cooling oil, and the battery module can be cooled by the cooling oil. The cooling oil flowing out of the battery 10 is supplied to the heater 11 through the second flow path 32.

[0021] The heater 11 corresponds to a "heater" that is driven by power supplied from the battery 10 and warms up the battery 10. The warming up of the battery 10 is performed, for example, in a situation where the temperature of the battery 10 is low, such as in winter when the air temperature is low. Here, the downstream side of the second flow path 32 is connected to the inlet of the heater 11, and the cooling oil is supplied to the reserve tank 12 through a third flow path 33 connected to the outlet of the heater 11. In the above-mentioned warming up, the heater 11 is driven to heat the cooling oil flowing into the heater 11, and the heated cooling oil moves to the battery module, thereby heating the battery 10. In addition, the heater 11 has a role of evaporating moisture in the cooling oil by heating the cooling oil described later.

[0022] The reserve tank 12 absorbs the volume expansion of the cooling oil caused by a rise in temperature to keep the amount of cooling oil circulating through the cooling circuit 50 constant, and also removes residual air contained in the cooling oil (gas-liquid separation). The inlet of the reserve tank 12 is connected to the downstream side of the third flow path 33, and the cooling oil is supplied to the heat exchanger 13 through a fourth flow path 34 connected to the outlet of the reserve tank 12.

[0023] The heat exchanger 13 corresponds to a "heat exchanger" that exchanges heat between the supplied cooling oil and a predetermined fluid. The heat exchanger 13 exhausts heat from the battery 10 and causes the cooling oil after heat exchange to flow out. The predetermined fluid is, for example, a cooling liquid for a refrigeration cycle, and the cooling liquid is supplied to the heat exchanger 13 by a cooling liquid supply pump 51. The refrigeration cycle is, for example, included in an air conditioner of the electric vehicle A, and by using the cooling liquid for the refrigeration cycle, the temperature of the cooling oil can be lowered compared to when air is used as the predetermined fluid. Here, the downstream side of the fourth flow path 34 is connected to the inlet of the heat exchanger 13, and the fifth flow path 35 is connected to the outlet of the heat exchanger 13. The cooling oil flowing out of the heat exchanger 13 is supplied to the battery 10 through the fifth flow path 35, the electric pump 14, and the first flow path 31. The cooling oil is cooled by the heat exchanger 13, and, for example, cooling oil at about room temperature flows into the battery 10. The temperature of the cooling oil flowing out of the heat exchanger 13 may be any temperature that can be tolerated by the battery 10. The heat exchanger 13 is also capable of changing the strength of cooling. Specifically, a control valve 15 is provided that is driven by power supplied from the battery 10 and can adjust the amount of coolant of the refrigeration cycle that flows into the heat exchanger 13, and the amount of coolant that flows in is increased by controlling the control valve 15 in the opening direction, thereby accelerating cooling.

[0024] The first temperature sensor 41 is disposed on the downstream side in the battery case of the battery 10, detects the temperature Tbat of the battery 10, and outputs a signal indicating the detected value to the control device 21.

[0025] The second temperature sensor 42 is disposed downstream in the first flow path 31, near the inlet for the cooling oil of the battery 10. The second temperature sensor 42 detects the temperature Tflow1 of the cooling oil passing through the first flow path 31, and outputs a signal indicating the detected value to the control device 21.

[0026] The third temperature sensor 43 is disposed downstream within the reserve tank 12, detects the temperature Tres of the cooling oil stored in the reserve tank 12, and outputs a signal indicating the detected value to the control device 21.

[0027] The fourth temperature sensor 44 is disposed in the fifth flow path 35 near the outlet of the heat exchanger 13. The fourth temperature sensor 44 detects the temperature Tflow5 of the cooling oil passing through the fifth flow path 35, and outputs a signal indicative of the detected value to the control device 21.

[0028] The control device 21 corresponds to a "control device" that has a control unit 22 and drives the heater 11, the heat exchanger 13, and the electric pump 14 at a predetermined timing. The heater 11 is driven in order to evaporate and remove moisture contained in the cooling oil, and the control unit 22 of the control device 21 opens the control valve 15 of the heat exchanger 13 at the same time as driving the heater 11. The driving of the heater 11 increases the temperature of the cooling oil flowing into the heater 11. This increase in the temperature of the cooling oil causes the moisture in the cooling oil to evaporate, and the evaporated moisture passes through the third flow path 33 and is separated into gas and liquid in the reserve tank 12. In addition, by opening the control valve 15 of the heat exchanger 13 at the same time as the driving of the heater 11, the heated cooling oil is cooled by heat exchange with the desired liquid, and the cooling oil flowing out of the heat exchanger 13 drops to, for example, about room temperature. This evaporates the moisture contained in the cooling oil to prevent deterioration of the cooling oil, and while increasing the withstand voltage of the electrical insulation, it is possible to suppress the inflow of high-temperature cooling oil into the battery 10. Here, the control unit 22 controls the driving of the heater 11 and the driving / stopping of the control valve of the heat exchanger 13 based on the detected cooling oil temperatures Tres and Tflow5. Specifically, the control device 21 drives the heater 11 so that Tres becomes a predetermined temperature, and drives the control valve 15 of the heat exchanger 13 so that Tflow5 becomes approximately room temperature.

[0029] The configuration of the control device 21 can be realized by the cooperation of hardware resources and software resources, or by hardware resources alone. Analog elements, microcomputers, DSPs, ROMs, RAMs, ASICs, FPGAs, and other LSIs can be used as hardware resources. Programs such as firmware can be used as software resources.

[0030] Fig. 3 is a flowchart showing the control of evaporating moisture by the control device 21 of Fig. 2. The process of Fig. 3 is periodically repeated by the control device 21. Note that, in this embodiment, "periodically" refers to a time interval at which not much moisture accumulates in the cooling oil, and is a predetermined interval determined in advance by experiments or the like.

[0031] First, the control unit 22 of the control device 21 drives the electric pump 14 to drive the control valve 15 of the heat exchanger 13 in the opening direction (S100). The driving of the electric pump 14 causes the cooling oil to circulate in the cooling circuit 50.

[0032] Next, the control unit 22 of the control device 21 drives the heater 11 when the cooling oil is circulating in the cooling circuit 50 (S101). By driving the heater 11, the cooling oil flowing from the third flow path 33 to the heater 11 is heated, and the temperature of the cooling oil increases.

[0033] Next, the control valve 15 is controlled so that the temperature Tflow1 of the cooling oil passing through the first flow path 31 and the temperature Tflow5 of the cooling oil passing through the fifth flow path 35 are less than the second predetermined value Tp2 (S102). Here, the second predetermined value Tp2 is a temperature that corresponds to the "second temperature" and is acceptable for the battery 10, and is set within a range of, for example, 30°C to 35°C. The control unit 22 of the control device 21 controls the opening degree of the control valve 15 so that the output value Tflow1 of the first temperature sensor 42 disposed in the first flow path 31 near the cooling oil inlet of the heater 11 and the output value Tflow5 of the fourth temperature sensor 44 disposed in the fifth flow path 35 near the outlet of the heat exchanger 13 are less than Tp2. In this embodiment, both Tflow1 and Tflow5 are controlled to be less than the second predetermined value Tp2, but either one of them may be controlled to be less than the second predetermined value Tp2.

[0034] Next, the control device 21 judges whether the temperature Tres of the cooling oil in the reserve tank 12 is equal to or higher than the first predetermined value Tp1 (S103). Specifically, the control unit 22 of the control device 21 judges whether the output value Tres of the third temperature sensor 43 arranged on the downstream side in the reserve tank 12 is equal to or higher than Tp1. When the output value Tres of the third temperature sensor 43 is less than the first predetermined value (No in S103), the process returns to S101. As will be described later, Tp1 corresponds to the "first temperature", for example, 50°C, and may be any temperature at which the moisture in the cooling oil evaporates to a predetermined degree or more. Preferably, by controlling the temperature to be equal to or higher than 50°C and lower than 80°C, thermal deterioration of the cooling circuit 50 such as the reserve tank having low heat resistance can be suppressed.

[0035] When it is determined that the temperature Tres of the cooling oil in the reserve tank 12 is equal to or higher than Tp1 (Yes in S103), the control section 22 of the control device 21 determines whether or not a predetermined time has elapsed since the cooling oil temperature Tres became equal to or higher than Tp1 (S104). If the predetermined time has not elapsed (No in S104), the process returns to S101. Here, the amount of water evaporation from the cooling oil depends on the heating time and the cooling oil temperature. That is, to achieve a predetermined amount of water evaporation, it is necessary to satisfy the relationship shown in FIG. 4. Specifically, when the cooling oil temperature is T1, water can be evaporated by heating for t1 time, but when the cooling oil temperature is T2 (<T1)であればt2(> It is necessary to heat the cooling oil for at least t1) time. There is such a relationship in the evaporation of moisture in the cooling oil, and the predetermined time in this embodiment may be a time that allows the cooling oil to be sufficiently heated by the heater 11 to evaporate the moisture. Here, the predetermined amount of moisture evaporation in this embodiment is determined based on the heating temperature of the heater 11.

[0036] When it is determined that a predetermined time or more has elapsed since the temperature Tres of the cooling oil in the reserve tank 12 became equal to or higher than Tp1 (Yes in S104), the control unit 22 of the control device 21 stops driving the heater 11 (S105).

[0037] Next, the control device 21 determines whether the temperature Tres of the cooling oil in the reserve tank 12 is less than a second predetermined value Tp3 (S106). Specifically, the control unit 22 of the control device 21 is disposed downstream in the reserve tank 12 and determines whether the temperature Tres of the cooling oil stored in the reserve tank 12 is less than Tp2 or more.

[0038] When it is determined that the output value Tres of the third temperature sensor 43 is equal to or greater than Tp2 (Yes in S106), the control unit 22 of the control device 21 stops the electric pump 14, drives the control valve 15 of the heat exchanger 13 in the closing direction, and ends the process (S107). Here, in this embodiment, the electric pump 14 is stopped and the control valve 15 of the heat exchanger 13 is driven in the closing direction, but this may be done stepwise as long as the driving is limited. Also, the driving of only one of the electric pump 14 and the control valve 15 of the heat exchanger 13 may be stopped or limited. In this case, the limit of the electric pump 14 means reducing the suction amount and discharge amount by the electric pump 14, and the limit of the heat exchanger 13 means reducing the inflow amount of the coolant of the refrigeration cycle by the above-mentioned opening and closing control of the control valve 15.

[0039] According to the embodiment, the heater 11 is periodically driven to raise the temperature of the cooling oil, and the moisture in the cooling oil is evaporated in the reserve tank 12. Here, in the present embodiment, the control valve 15 of the heat exchanger 13 is driven in the opening direction together with the driving of the heater 11. The cooling oil heated by the heater 11 flows into the battery 10 via the reserve tank 12 and the heat exchanger 13. As described above, cooled cooling oil flows into the battery 10, and therefore it is possible to suppress thermal deterioration of the battery 10, which would occur when high-temperature cooling oil flows into the battery 10 when the moisture is evaporated.

[0040] Here, a control method for operating the heater 11 to warm up the battery 10 will be described with reference to the flowchart of FIG.

[0041] FIG. 5 is a flow chart showing the control for warming up the battery 10 in the control device 21. This control is started based on the temperature of the battery 10.

[0042] The control device 21 determines whether the temperature Tbat of the battery 10 is less than a third predetermined value Tp3 (S200). Specifically, the control unit 22 of the control device 21 determines whether the output value Tbat of the first temperature sensor 41 disposed downstream in the battery case of the battery 10 is less than Tp3.

[0043] Next, when the temperature Tbat of the battery 10 is less than Tp4 (Yes in S200), it is determined whether the temperature Tflow1 of the cooling oil is less than a fourth predetermined value Tp3. Specifically, the control unit 22 of the control device 21 determines whether the output value Tflow1 of the second temperature sensor 42 disposed downstream in the first flow path 31 and near the inlet of the cooling oil of the battery 10 is less than Tp4 (S201). Here, Tp4 is a temperature higher than Tp3 and lower than Tp2, for example, Tp3 is 0°C and Tp4 is 25°C.

[0044] When the temperature of the cooling oil in the first cooling path is less than Tp4 (Yes in S201), the heater 11 is driven (S202), and the process returns to S200. At this time, the control valve 15 of the heat exchanger 13 is driven in the closing direction, or the opening and closing control of the control valve 15 is used to limit the cooling by the heat exchanger 13, thereby maintaining a temperature at which the battery 10 can be warmed up. As a result, the heat generated by the heater 11 is transferred to the battery 10 via the cooling oil, and the battery 10 can be warmed up. Furthermore, if the heater 11 was already driven, it is allowed to continue to be driven.

[0045] When the temperature Tbat of the battery 10 is equal to or higher than Tp3 or the temperature Tflow1 of the cooling oil is equal to or higher than Tp4 (No in S200, No in S201), the control unit 22 of the control device 21 does not drive the heater 11, but drives the control valve of the heat exchanger 13 in the opening direction (S203). At this time, if the control valve 15 of the heat exchanger 13 has already been controlled in the opening direction, the control in the opening direction is continued, and room temperature cooling oil is caused to flow into the battery 10.

[0046] In this manner, in the embodiment, the driving of the heater 11 and the control valve 15 of the heat exchanger 13 is switched in response to the evaporation of water in the cooling oil and the warming up of the battery 10. This allows one heater 11 to be used for both evaporating water from the cooling oil and warming up the battery 10, thereby reducing costs.

[0047] <Modification> In the control for evaporating water in the above embodiment, the second predetermined value Tp2 may be changed based on the temperature of the battery 10. Specifically, it is set based on the output value of the first temperature sensor 41 arranged downstream in the battery case of the battery 10. For example, when the temperature of the battery 10 corresponds to the "third temperature" below freezing, Tp2 is set to a high value so that cooling oil at a temperature that allows the battery 10 to be warmed up is introduced. This causes the cooling by the heat exchanger 13 to be stopped or limited early, and the cooling of the cooling oil is suppressed, making it possible to warm up the battery 10, and the evaporation of water from the cooling oil and the warming up of the battery 10 can be performed simultaneously.

[0048] In the above embodiment, the control of evaporating the moisture in Fig. 3 is described as being performed periodically, but it may be performed when the temperature of the cooling oil is low and the moisture in the cooling oil is not expected to evaporate. Specifically, the control of evaporating the moisture is performed when the temperature Tbat of the battery 10 or the output value Tres of the third temperature sensor 43 is 50°C or less, which is a temperature at which the moisture in the cooling oil is not expected to evaporate. In the above situation, the moisture in the cooling oil is unlikely to evaporate and there is a high possibility that moisture remains in the cooling oil, so that the moisture in the cooling oil can be efficiently reduced by heating the cooling oil with the heater 11.

[0049] In addition, the heating by the heater 11 may have different heat amounts for removing moisture from the cooling oil and for warming up the battery. Specifically, the heating for removing moisture from the cooling oil is performed with a larger heat amount than the heating for warming up the battery. A large heat amount is required to evaporate the moisture from the cooling oil, but a temperature that ensures the output of the battery, for example, about 20 to 25°C in winter, is sufficient for warming up the battery. Even if the cooling oil is heated by the heater 11 to a temperature that can evaporate the moisture in the cooling oil in order to warm up the battery 11, the heat exchanger 13 cools the cooling oil to a temperature that the battery can tolerate, so that unnecessary heating occurs. By setting the heat amount as described above, unnecessary heating can be suppressed and the consumption of the battery 10 can be reduced.

[0050] In the modified example, one heater 11 is used for both evaporating water from the cooling oil and warming up the battery 10, but a heater for evaporating water from the cooling oil and a heater for warming up the battery 10 may be provided separately. In that case, the heater for evaporating water from the cooling oil may be disposed at the position of the heater 11, and the heater for warming up the battery 10 may be disposed on the first flow path 31. Also, only one of the first temperature sensor 41 and the fourth temperature sensor 44 may be provided.

[0051] Furthermore, the control for evaporating the moisture in the cooling oil may be performed when the electric vehicle A is being charged. By performing the control at this timing, it is possible to suppress a decrease in the output of the battery 10 that would be caused by performing the control while the vehicle is running. As another timing, the control may be performed when the electric vehicle A is stopped with the ignition turned off. Performing the control at such a timing can also achieve the above-mentioned effects.

[0052] In addition, in the embodiment and modified examples, the strength of cooling of the heat exchanger is adjusted by the control valve 15, but the strength of cooling of the heat exchanger may also be adjusted by controlling the flow rate of the coolant supply pump 51 of the refrigeration cycle.

[0053] The present invention has been described above based on the embodiments. The embodiments are merely examples, and it will be understood by those skilled in the art that multiple modifications are possible in the combination of each component and each processing step, and that such modifications are also within the scope of the present invention. [Explanation of symbols]

[0054] 1 Battery Cooling System 10 Battery 11 Heater 12 Reserve tank 13 Heat exchanger 14 Electric Pump 21 Control device 22 Control section 51 Coolant supply pump A Electric vehicle

Claims

1. A battery; a heater for heating a cooling oil for cooling the battery; a reserve tank capable of separating the cooling oil into gas and liquid; a heat exchanger for exchanging heat between the cooling oil and a predetermined fluid; A control device for controlling the heater and the heat exchanger; A battery cooling system comprising: The cooling oil flows through the heater, the reserve tank, the heat exchanger, and the battery in this order. The control device controls the heater to heat the cooling oil to a first temperature at which moisture in the cooling oil evaporates, and controls the heat exchanger to cool the cooling oil to a second temperature lower than the first temperature.

2. The battery cooling system according to claim 1 , wherein the control device changes the second temperature based on a temperature of the battery.

3. 3. The battery cooling system according to claim 1, wherein the control device sets the second temperature higher when the temperature of the battery is lower than a third temperature than when the temperature of the battery is higher than the third temperature.

4. At least one of the heater, the control device, and a control valve that controls the amount of coolant flowing into the heat exchanger is supplied with power from the battery; 4. The battery cooling system according to claim 1, wherein the control device controls the heater to heat the cooling oil to a first temperature at which moisture in the cooling oil evaporates, and the heat exchanger to cool the cooling oil to a second temperature lower than the first temperature, when the vehicle is being charged.

5. A method for controlling a battery cooling system that cools a battery by cooling oil, comprising: a heating step of heating the cooling oil to a first temperature at which moisture in the cooling oil evaporates; a cooling step of cooling the cooling oil to a second temperature lower than the first temperature before the cooling oil reaches the battery after being heated; A method for controlling a battery cooling system comprising:

6. 6. The method for controlling a battery cooling system according to claim 5, further comprising changing the second temperature based on a temperature of the battery.

7. 7. The method for controlling a battery cooling system according to claim 5, wherein when the temperature of the battery is lower than a third temperature, the second temperature is set higher than when the temperature of the battery is higher than the third temperature.

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