Battery cooling system

Abstract

Provided is a storage battery cooling system capable of rapidly cooling a storage battery while suppressing heating of the storage battery. The storage battery cooling system includes a cooling fan that draws air in a vehicle cabin into an intake passage and delivers the air to the storage battery, and a control unit that controls the cooling fan based on an intake temperature and a storage battery temperature detected by an intake temperature sensor and a storage battery temperature sensor. After the cooling fan is operated to deliver air to the storage battery, the control unit performs a temperature check operation in which the cooling fan is stopped and a difference between the intake temperature and the storage battery temperature is calculated. In the case where the difference is greater than zero, the temperature check operation is repeated. In the temperature check operation after the second time, in the case where the difference is greater than zero and the difference at this time is smaller than the difference at the previous time, the temperature check operation at the next time is performed.

Description

TECHNICAL FIELD

[0001] The present application relates to a battery cooling system that cools a battery mounted on a vehicle. BACKGROUND

[0002] A battery is mounted on a vehicle such as an electric vehicle or a hybrid vehicle as a drive source. The battery can have its performance reduced or its life shortened due to excessive temperature rise, so a battery cooling system that cools the battery is mounted on the vehicle such as an electric vehicle.

[0003] The battery cooling system generally has an intake duct arranged between a vehicle cabin and a battery located outside the vehicle cabin, and a cooling fan arranged in the intake duct, and sucks air in the vehicle cabin, which has been air-conditioned by the cooling fan, into the intake duct and delivers it to the battery side, thereby cooling the battery. In addition, in order to avoid the battery being heated by air that is higher in temperature than the battery, intake temperature checking is performed in which the battery temperature and the temperature of air passing through the intake duct (i.e., the intake temperature) are detected by sensors, respectively, and it is determined whether or not to start cooling the battery by the cooling fan (for example, Patent Literature 1).

[0004] In such a battery cooling system, when the cooling fan is stopped, air remains in the intake duct, so after the air in the intake duct is discharged and air in the vehicle cabin is sucked into the intake duct, intake temperature checking is performed in which the battery temperature and the intake temperature are compared.

[0005] In the battery cooling system described in Patent Literature 1, as intake temperature checking control that checks the intake temperature, a method is adopted in which when the battery becomes high in temperature, the cooling fan is continuously driven to send out a volume of air in the intake duct, after the volume of air is sent out, the intake temperature in the intake duct and the battery temperature are acquired, respectively, and the intake temperature and the battery temperature are compared, and cooling of the battery is started in the case where the intake temperature is lower than the battery temperature.

[0006] In the battery cooling system described in Patent Literature 1, the intake temperature checking is performed by sending out the air in the intake duct at one time, so the intake temperature checking can be ended early, and cooling of the battery can be started promptly.

[0007] PRIOR ART DOCUMENTS

[0008] PATENT LITERATURE

[0009] Patent Literature 1: Japanese Patent Application Publication No. 2018-95061 SUMMARY

[0010] Figure 5is a graph showing one example of intake air temperature check control in the battery cooling system described in Patent Literature 1, the vertical axis indicates intake air temperature and battery temperature, the solid line indicates the time-series change of the battery temperature, and the broken line indicates the time-series change of the intake air temperature. As described above, in the battery cooling system of Patent Literature 1, although it is possible to end the intake air temperature check early, in the case where the vehicle is left in hot weather and the intake air pipe is at a high temperature, as shown in Figure 5 indicated by the solid line, if the cooling fan is operated to send out the volume of air in the intake air pipe at one time in order to perform the intake air temperature check, the high-temperature air in the intake air pipe is delivered to the battery side at one time, the battery temperature sharply rises, and the battery can become in an overheated state.

[0011] In addition, in the case where even if the volume of air in the intake air pipe is exhausted, the air in the passenger compartment passes through the high-temperature intake air pipe and is heated to be higher than the temperature of the passenger compartment, as shown in Figure 5 indicated by the solid line, the intake air temperature X A detected by the intake air temperature sensor is sometimes higher than the battery temperature X B detected by the battery temperature sensor. Furthermore, in Figure 5 , ΔT A indicates the difference obtained by subtracting the battery temperature X A from the intake air temperature X B . Thus, in the conventional intake air temperature check, although the temperature of the air in the passenger compartment is lower than the battery temperature, the drive of the cooling fan is stopped after the intake air temperature check, and sometimes the battery cannot be cooled properly.

[0012] The present application is proposed in view of the above-described problems, and aims to provide a battery cooling system capable of starting cooling of a battery while suppressing heating of the battery.

[0013] To achieve the above object, a storage battery cooling system according to an embodiment of the present application includes: a cooling fan that draws air in a vehicle cabin into an intake passage that communicates the vehicle cabin with a storage battery, and supplies the air to the storage battery; a storage battery temperature sensor that detects a temperature of the storage battery; an intake air temperature sensor that is disposed in the intake passage, and detects a temperature of air passing through the intake passage; and a control unit that controls operation of the cooling fan based on an intake air temperature detected by the intake air temperature sensor and a storage battery temperature detected by the storage battery temperature sensor, characterized in that the control unit performs a temperature check operation in which the cooling fan is stopped after the cooling fan is operated to supply air to the storage battery, and a difference between the intake air temperature and the storage battery temperature is calculated, and in a case where the difference is greater than zero, the temperature check operation is repeated, and in a case where the difference in the temperature check operation this time is smaller than the difference in the temperature check operation last time and the difference this time is greater than zero in the temperature check operation after the second time, the control unit performs the temperature check operation next time.

[0014] According to this structure, in a case where the difference between the intake air temperature and the storage battery temperature is greater than zero, the control unit repeats the temperature check operation, whereby the operation and the stop of the cooling fan are repeated, so that even if the air temperature in the vehicle cabin is lower than the storage battery temperature, the storage battery can be prevented from not being cooled. In addition, even in a case where the difference is greater than zero, in a case where the air temperature in the vehicle cabin is lower than the storage battery temperature, the difference gradually becomes smaller by continuing the air supply, so that in the temperature check operation after the second time, in a case where the calculated difference is smaller than the difference in the temperature check operation last time, by performing the temperature check operation next time, the heating of the storage battery can be suppressed, and the time until the difference becomes below zero (i.e., the storage battery can be cooled by the cooling fan) can be shortened, whereby the control of the temperature check can be ended early, and the cooling of the storage battery can be started.

[0015] In addition, a storage battery cooling system according to an embodiment of the present application is characterized in that, in a case where the difference in the temperature check operation this time is smaller than the difference in the temperature check operation last time, the control unit increases the air volume of air supplied to the storage battery in the temperature check operation next time, compared to the air volume in the temperature check operation this time.

[0016] According to this structure, in the temperature check operation after the second time, in a case where the difference calculated in the present temperature check operation is smaller than the difference of the temperature check operation of the previous time, the air volume in the next temperature check operation is increased from the air volume of the present time, so that the time until the battery can be cooled by the cooling fan (i.e., the time until the difference calculated in the temperature check operation becomes zero or less) can be shortened. Thus, the control of the temperature check can be ended early, and the cooling of the battery can be started.

[0017] Further, one embodiment of the present application according to the battery cooling system is characterized in that the control section increases the air volume in the next temperature check operation of the temperature check operation by increasing the duty ratio of the cooling fan.

[0018] Further, one embodiment of the present application according to the battery cooling system is characterized in that the control section increases the air volume in the next temperature check operation of the temperature check operation by increasing the duty ratio of the cooling fan.

[0019] According to this structure, the air volume in the next temperature check operation can be increased from the air volume of the present time by the increase of the duty ratio of the cooling fan and the increase of the driving time of the cooling fan.

[0020] Further, one embodiment of the present application according to the battery cooling system is characterized in that the control section resets the control of the temperature check operation in the temperature check operation after the second time, in a case where the difference of the present temperature check operation is equal to or greater than the difference of the temperature check operation of the previous time.

[0021] According to this structure, in a case where the difference of the present temperature check operation is equal to or greater than the difference of the temperature check operation of the previous time, i.e., in a case where the battery can be erroneously heated by the operation of the cooling fan, the control of the temperature check is reset, so that the erroneous heating can be prevented.

[0022] According to the battery cooling system of the present application, the cooling of the battery can be started while suppressing the heating of the battery. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a diagram schematically illustrating a battery cooling system according to one embodiment of the present application.

[0024] Figure 2 is a diagram illustrating a control mechanism of the battery cooling system.

[0025] Figure 3 is a flowchart illustrating an intake air temperature check control by the control section.

[0026] Figure 4(A) is a graph showing time-series changes of the battery temperature, the intake air temperature, and the vehicle cabin temperature, and (B) is a graph showing time-series changes of the duty ratio of the cooling fan.

[0027] Figure 5 is a graph showing time-series changes of the battery temperature and the intake air temperature when the intake air temperature check is performed in the conventional battery cooling system.

[0028] (Explanation of Reference Numerals)

[0029] 10 battery cooling system; 12 battery case; 14 intake air pipe; 15a, 15b, 15c, 15d, 15e branch pipe; 16 exhaust pipe; 20 cooling fan; 22 fan motor; 30 intake air temperature sensor; 34 battery temperature sensor; 40 ECU (control section). DETAILED DESCRIPTION

[0030] Figure 1 is a schematic explanatory view of a battery cooling system as an embodiment of the present application, Figure 2 is an explanatory view of a control mechanism of the battery cooling system. The battery cooling system 10 of the present application is applied to a vehicle using a battery BT as a drive source, such as an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle.

[0031] The battery cooling system 10 is provided with a battery BT mounted on a vehicle, an intake air pipe 14 forming an intake passage that communicates a vehicle cabin and the battery BT, a cooling fan 20 that sucks air in the vehicle cabin into the intake air pipe 14 to deliver it to the battery BT, and an exhaust pipe 16 for discharging the air delivered to the battery BT to the outside of the vehicle. In addition, the battery cooling system 10 is provided with an intake air temperature sensor 30 that detects the temperature of the air passing through the intake passage (hereinafter, also referred to as the intake air temperature), a battery temperature sensor 34 that detects the temperature of the battery BT, and an ECU (Electronic Control Unit) 40 as a control section.

[0032] The battery BT is housed in a battery case 12 formed outside the vehicle cabin. The battery case 12 can be disposed, for example, under a trunk in the rear portion of the vehicle. In the present embodiment, the battery BT is composed of five battery groups, i.e., a first battery group BS1, a second battery group BS2, a third battery group BS3, a fourth battery group BS4, and a fifth battery group BS5. Each of the battery groups BS1 to BS5 is composed of stacked battery cells that generate electricity.

[0033] The intake duct 14 communicates the vehicle cabin with the battery case 12 in which the battery BT is housed. In the present embodiment, the intake duct 14 is branched into a plurality of ducts on the downstream side thereof, so as to deliver the air in the vehicle cabin to each of the battery groups BS1 to BS5. Specifically, two intake ducts 14A, 14B are provided between the vehicle cabin and the battery case 12, the first intake duct 14A is branched into two branch ducts 15a, 15b on the downstream side thereof, the first branch duct 15a is connected to the first battery group BS1, and the second branch duct 15b is connected to the second battery group BS2. Further, the second intake duct 14B is branched into three branch ducts 15c, 15d, 15e on the downstream side thereof, the first branch duct 15c is connected to the third battery group BS3, the second branch duct 15d is connected to the fourth battery group BS4, and the third branch duct 15e is connected to the fifth battery group BS5.

[0034] The cooling fan 20 is driven by a fan motor 22 connected to the ECU 40, so as to supply the air in the vehicle cabin to the battery BT. The cooling fan 20 is provided to each of the intake ducts 14, and in the present embodiment, a first cooling fan 20A is provided to the first intake duct 14A, and a second cooling fan is provided to the second intake duct 14B. The first cooling fan 20A and the second cooling fan 20B can be individually driven by the first fan motor 22A and the second fan motor 22B, respectively. Further, in the illustrated example, the cooling fan 20 is provided to the intake duct 14 side, so as to press the air in the duct to the outside of the vehicle, but the cooling fan 20 can be provided to the exhaust duct 16 side, so as to suck the air in the duct to the outside of the vehicle.

[0035] The exhaust duct 16 forms an exhaust passage that exhausts the air delivered to the battery BT via the intake duct 14 to the outside of the vehicle. In the present embodiment, the upstream end of the exhaust duct 16 is branched into portions connected to the first to fifth battery groups BS1 to BS5, respectively.

[0036] The intake temperature sensor 30 is provided to the intake passage, so as to detect the temperature Ta (hereinafter, also referred to as the intake temperature Ta) of the air passing through the intake duct 14. The intake temperature sensor 30 is preferably provided to a region near the battery case 12 in the intake passage, in consideration of the temperature change in the intake passage, the influence on the battery BT, and the like. In the battery cooling system 10 of the present embodiment, two intake temperature sensors 30 are provided, namely, a first intake temperature sensor 30A provided near the second battery group BS2 in the first intake duct 14A, and a second intake temperature sensor 30B provided near the third battery group BS3 in the second intake duct 14B.

[0037] The battery temperature sensor 34 detects the temperature Tb (hereinafter, also referred to as battery temperature Tb) of the battery BT, which is mounted in or on the surface of the battery case 12, directly or indirectly detects the temperature of the battery BT. In the present embodiment, in each intake pipe 14A, 14B, the path length is long, and the temperature in the pipe easily becomes the highest, and the first battery temperature sensor 34A and the second battery temperature sensor 34B are mounted in the second battery group BS2 and the third battery group BS3, respectively.

[0038] The ECU 40 controls the devices mounted on the vehicle equipped with the battery cooling system 10. The ECU 40 is configured to have, for example, an information processing unit such as a central processing unit (CPU), an application specific integrated circuit (ASIC), a storage unit such as a RAM, a ROM, and an input / output interface. The ECU 40 of the present embodiment controls the operation of the cooling fan 20 based on the detected temperatures of the intake temperature sensors 30 and the battery temperature sensors 34, and is electrically connected to each temperature sensor 30A, 30B, 34A, 34B and each fan motor 22A, 22B.

[0039] The control of the ECU 40 of the cooling fan 20 can simultaneously control each cooling fan 20A, 20B based on the highest temperature of each intake temperature sensor 30A, 30B and the highest temperature of each battery temperature sensor 34A, 34B. Alternatively, each cooling fan 20A, 20B can be individually controlled by each intake temperature sensor 30A, 30B and each battery temperature sensor 34A, 34B provided in each air passage from each intake pipe 14A, 14B to the exhaust pipe 16. In the following description, the control of the ECU 40 is described as the control of simultaneously controlling each cooling fan 20A, 20B using the highest temperature of each temperature sensor.

[0040] The ECU 40 has a storage portion 42 that stores information designated in relation to the intake temperature check control and the battery cooling control after the intake temperature check control. Further, the ECU 40 has a calculation portion 44 that calculates the difference ΔT = Ta - Tb N , and a determination portion 46 that determines the subsequent operation based on the information of the storage portion 42, the detection results of each sensor, and the calculation result of the calculation portion 44. N in the difference ΔT N is a positive integer value (N = 1, 2,..., m) that changes according to the number of temperature check operations described later.

[0041] In the storage portion 42, a battery cooling reference temperature Tb th that becomes a reference for requiring the cooling of the battery BT in the battery cooling system 10 is set. As one example, the battery cooling reference temperature Tb th36°C.

[0042] In addition, in the storage section 42, control values for controlling the rotation of the cooling fan 20 in the intake air temperature check control are set in advance. As shown in Table 1, the control values are constituted by a combination of a duty ratio D n (unit: %) of PWM control (control that repeatedly turns on and off at a certain cycle) of the cooling fan 20 n and a time t n (unit: sec) during which the cooling fan 20 is driven at the duty ratio D N .

[0043] [Table 1]

[0044]

[0045] In the intake air temperature check control, in the case where the intake air temperature Ta is higher than the battery temperature Tb, the ECU 40 performs a series of actions in which, after the cooling fan 20 is driven at a specified duty ratio D n for a specified time t n to send air to the battery BT, the cooling fan 20 is stopped for a specified time t X , the intake air temperature Ta and the battery temperature Tb are detected, and a difference ΔT N obtained by subtracting the battery temperature from the intake air temperature is calculated. In this specification, this series of actions is referred to as a "temperature check action". In the battery cooling system 10 of the present embodiment, in the temperature check action after the second time, in the case where the difference ΔT N of this time is greater than zero and the difference ΔT N of the temperature check action of this time is smaller than the difference ΔT N-1In the case where the battery temperature Tb exceeds the battery cooling reference temperature Tb th in the next (i.e., after the third) temperature check operation, the air volume to be delivered to the battery BT is increased compared to the present temperature check operation. It is preferable that the air volume to be delivered to the battery in the temperature check operation is less than the volume of the intake pipe 14. In the present embodiment, at least in each of the first to third temperature check operations, the air volume to be delivered to the battery BT is set to be less than the volume of the intake pipe 14. Further, in each of the temperature check operations, the air volume to be delivered to the battery BT by the cooling fan 20 can be appropriately set, and for example, can be the same air volume each time (i.e., the same air volume as the first time even after the third time), or can be different air volumes each time.

[0046] Next, the intake air temperature check control performed by the ECU 40 will be specifically described with reference to the flowchart of Figure 3 .

[0047] First, the ECU 40 determines whether the battery temperature Tb exceeds the battery cooling reference temperature Tb th (Step S12) if it is detected that the vehicle equipped with the battery cooling system 10 is in a state where it is able to travel by the drive source, i.e., the system is in a started state (Step S10). In the case where the battery temperature Tb is the battery cooling reference temperature Tb th or less (Step S12: No), the determination of Step 12 is repeatedly performed (Step S12: No).

[0048] In the case where the battery temperature Tb exceeds the battery cooling reference temperature Tb th (Step S12: Yes), the parameter n as the control value of the cooling fan 20 and the parameter N as the difference AT N calculated by the calculation portion 44 are respectively set to 1 (n = N = 1), and the processing proceeds to the next processing (Step S14).

[0049] In the next processing (Step S16), the cooling fan 20 is driven at the specified duty ratio Dl for the specified time tl based on the control value stored in the storage portion 42, and thereafter, the cooling fan 20 is stopped. After the cooling fan 20 is stopped and the specified time t X elapses, it is determined whether the intake air temperature Ta is the battery temperature Tb or less (i.e., whether the difference obtained by subtracting the battery temperature Tb from the intake air temperature Ta is zero or less) (Step S18). Here, the operation from Step S16 to Step S18 corresponds to the first temperature check operation.

[0050] In the case where the intake air temperature Ta is lower than the battery temperature Tb (step S18: YES), it is a state where the battery can be cooled, so the intake air temperature check control is ended (END), and the cooling fan 20 is driven based on the control value of the battery cooling control stored in advance in the storage section 42, and the cooling of the battery BT is started.

[0051] In the case where the intake air temperature Ta is greater than the battery temperature Tb in step S18 (step S18: NO), the difference ATl obtained by subtracting the battery temperature Tb from the intake air temperature Ta is stored in the storage section 42 (step S20). Next, the cooling fan 20 is driven again at the specified duty ratio Dl for the specified time tl, and thereafter, the cooling fan 20 is stopped (step S22). After the cooling fan 20 is stopped and the specified time t X Thereafter, it is determined whether the intake air temperature Ta is lower than the battery temperature Tb (step S24). Here, the operation from step S22 to step S24 corresponds to the second temperature check operation.

[0052] In the case where the intake air temperature Ta is lower than the battery temperature Tb in step S24 (step S24: YES), the intake air temperature check control is ended, and the cooling fan 20 is driven based on the control value of the battery cooling control set in advance in the storage section 42, and the cooling of the battery BT is started.

[0053] In the case where the intake air temperature Ta is greater than the battery temperature Tb in step S24 (step S24: NO), the parameters n and N, which are the control values of the cooling fan 20, and the difference AT2 calculated by the calculation section 44 are each added by 1 (n = n + 1, N = N + 1) (step S26), the difference AT2 obtained by subtracting the battery temperature Tb from the intake air temperature Ta is stored in the storage section 42 (step S28), and the processing is shifted to the next processing. N

[0054] In the next step S30, it is determined whether the difference AT2 calculated this time is less than the difference ATl of the previous temperature check operation (here, the first temperature check operation).

[0055] In the case where the difference AT2 this time is equal to or greater than the difference ATl of the previous time (step S30: NO), the air of a higher temperature than the battery BT is delivered, and the battery BT can be erroneously heated, so the intake air temperature check control performed up to this point is reset, and the intake air temperature check control is started again from step S12. After the reset, the parameters n and N are restarted from 1 by step S14.

[0056] ​On the other hand, if the current difference ΔT2 is less than the previous difference ΔT1 (step S30: Yes), in order to expel the warm air from the intake pipe 14, the cooling fan 20 is driven with a specified duty cycle D2 larger than the previous value for a specified time t2, after which the cooling fan 20 is stopped (step S32). After the cooling fan 20 is stopped and the specified time t has elapsed... X Next, it is determined whether the intake air temperature Ta is below the battery temperature Tb (step S34). Here, the actions from step S32 to step S34 are equivalent to the third temperature check action.

[0057] In step S34, if the intake air temperature Ta is below the battery temperature Tb (step S34: Yes), the intake air temperature check control ends, and the cooling fan 20 is driven to start cooling the battery BT based on the control value of the battery cooling control preset in the storage unit 42.

[0058] In step S34, if the intake air temperature Ta is greater than the battery temperature Tb (step S34: No), return to step S26, and calculate the difference ΔT between the parameter n, which is the control value of the cooling fan 20, and the calculation unit 44. N The parameter N is added by 1 to each of the parameters (n = n + 1, N = N + 1). Here, it is set to n = N = 3, which is obtained by adding 1 to each of the parameters n = N = 2. Then, the process proceeds to step S28 to continue with the subsequent processing. For example... Figure 3 As shown in steps S26 to S34 of the process, the intake air temperature is checked and controlled so that the battery temperature Tb is greater than the battery cooling reference temperature Tb. th The process continues until the intake air temperature Ta falls below the battery temperature Tb. Each time the number of temperature check actions is increased, parameters n and N are each incremented by 1, and PWM control of the cooling fan 20 is performed based on this variable.

[0059] As described above, in the intake air temperature check control of the battery cooling system 10 in this embodiment, in subsequent temperature check operations, the airflow delivered by the cooling fan 20 to the battery BT is controlled to increase compared to the previous temperature check operation. That is, in the case of the Nth check, the operation of the cooling fan 20 is controlled such that the airflow ratio is increased compared to the previous (N-1)th temperature check operation. In this embodiment, the ECU 40 controls the operation of the cooling fan 20 by adjusting the drive time t... n Increase and make the duty cycle D of cooling fan 20 n This increases the airflow during the temperature check process.

[0060] Figure 4 This is a graph illustrating an example of four temperature checks being performed in intake air temperature check control. Figure 4(A) is a graph showing the time-series changes in battery temperature Tb, intake air temperature Ta, and cabin temperature. Figure 4 (B) is a graph showing the time-series change of the cooling fan's duty cycle. Furthermore, the cabin temperature can be detected by a cabin temperature sensor located inside the cabin or at the cabin-side end of the air intake duct 14. Figure 4 In (A) and (B), the time axis (horizontal axis) is consistent.

[0061] For example, if the vehicle is parked in hot weather and the intake manifold 14 is at a high temperature, such as Figure 4 As shown, even when the cabin temperature is lower than the battery temperature Tb using air conditioning, the intake air temperature Ta passing through the intake manifold 14 is sometimes higher than the battery temperature Tb. In such cases, if the cooling fan 20 is rotated at a lower speed than when cooling the battery via intake air temperature monitoring control, the high-temperature air trapped in the intake manifold 14 is delivered, causing the intake air temperature detected by the intake air temperature sensor 30 located near the outlet of the intake manifold 14 to rise. At this time, if... Figure 5 As shown in the conventional intake temperature check and control, if the cooling fan 20 is continuously driven to exhaust the volume of air from the intake pipe 14 at once, the high-temperature air is delivered to the battery BT in one go, and the battery temperature Tb rises sharply, which may result in an overheating state.

[0062] In contrast, in the battery cooling system 10 of this embodiment, such as Figure 4 As shown in (B), the repeated driving and stopping of the cooling fan 20 makes the air volume delivered by each drive less than the volume of the intake pipe 14. Thus, even if there is hot air trapped in the intake passage, it is possible to prevent the hot air from being delivered to the battery BT at once, which would cause the battery temperature Tb to rise sharply.

[0063] Furthermore, in the battery cooling system 10 of this embodiment, such as Figure 4 As shown, the difference ΔT obtained by subtracting the battery temperature Tb from the intake air temperature Ta... N Less than the difference ΔT of the previous one N-1 In this case, so that the duty cycle D of the cooling fan 20 is... n Compared to the previous duty cycle D n-1 Increase, and the driving time t of cooling fan 20 n Compared to the previous drive time t n-1 The increased method controls the operation of cooling fan 20. Even with the difference ΔT... N When the value is greater than zero, and the air temperature in the vehicle compartment is lower than the battery temperature Tb, the difference ΔT is maintained by continuing to supply air through the cooling fan 20. N It gradually decreases, so in subsequent temperature checks, the calculated difference ΔT...N the difference ΔT of the previous temperature check operation N-1 In this case, by increasing the air volume in the next temperature check operation than this time, the time until the difference becomes zero or less (i.e., the intake air temperature Ta becomes the battery temperature Tb or less, and the battery BT can be cooled by the cooling fan 20) can be shortened. Thus, the intake air temperature check control can be ended early, and the battery BT can be rapidly and reliably started to be cooled in the case where the cabin temperature is lower than the battery temperature Tb. Further, as Figure 4 (A) shown, the difference ΔT can be continuously detected, and in the case where the difference ΔT N becomes zero or less (time t Y ) after the start of the intake air temperature check control, the battery cooling control is started.

[0064] Further, in the battery cooling system 10 of the present application, with respect to the increase in the air volume of the cooling fan 20 when the temperature check operation is repeated a plurality of times, the drive time t n may be constant and only the duty ratio D n may be increased, or the duty ratio D n may be constant and only the drive time t n may be increased, or the duty ratio D n and the drive time t n may be constant and the rotation speed of the cooling fan 20 may be increased, but as in the above-described embodiment, the drive time t n and the duty ratio D n are increased together, the air volume is made large every time the number of temperature check operations is increased, and thus the intake air temperature check control is ended early, and the battery BT can be more rapidly started to be cooled.

[0065] Further, in the intake air temperature check control, in the temperature check operation after the second time, the difference ΔT N is greater than zero and the difference ΔT N is the difference ΔT N-1 of the previous temperature check operation, the air temperature in the cabin is higher than the battery temperature Tb, and the battery BT can be erroneously heated by driving the cooling fan 20. Therefore, in such a case, the intake air temperature check control is reset, and the cooling of the battery BT by the cooling fan 20 is not performed (i.e., the cooling fan 20 is continuously driven), and thus the erroneous heating of the battery BT can be prevented.

[0066] Further, the present application is not limited to the above-described embodiments, and various modifications can be made within the scope of the present application.

Claims

1. A battery cooling system comprising: a cooling fan that draws air in a vehicle cabin into an intake passage that communicates the vehicle cabin with a battery and delivers the air to the battery; a battery temperature sensor that detects a temperature of the battery; an intake temperature sensor that is disposed in the intake passage and detects a temperature of air passing through the intake passage; and a control unit that controls operation of the cooling fan based on an intake temperature detected by the intake temperature sensor and a battery temperature detected by the battery temperature sensor, characterized in that the control unit performs a temperature check operation in which the cooling fan is stopped after the cooling fan is operated to deliver air to the battery and a difference between the intake temperature and the battery temperature is calculated, and in a case where the difference is greater than zero, the temperature check operation is repeated, an air volume of air delivered to the battery in one of the temperature check operations being smaller than a volume of the intake passage, the control unit performs the next temperature check operation in a case where the difference in the present temperature check operation is smaller than the difference in the previous temperature check operation and the difference in the present temperature check operation is greater than zero in the temperature check operation after the second time.

2. The battery cooling system according to claim 1, characterized in that the control unit increases the air volume of air delivered to the battery in the next temperature check operation than the air volume in the present temperature check operation in a case where the difference in the present temperature check operation is smaller than the difference in the previous temperature check operation.

3. The battery cooling system according to claim 2, characterized in that the control unit increases the air volume in the next temperature check operation by increasing a driving time of the cooling fan.

4. The battery cooling system according to claim 2 or 3, characterized in that the control unit increases the air volume in the next temperature check operation by increasing a duty ratio of the cooling fan.

5. The battery cooling system according to any one of claims 1 to 3, characterized in that the control unit resets the control of the temperature check operation in a case where the difference in the present temperature check operation is equal to or greater than the difference in the previous temperature check operation in the temperature check operation after the second time.

6. The battery cooling system according to claim 4, characterized in that the control unit resets the control of the temperature check operation in a case where the difference in the present temperature check operation is equal to or greater than the difference in the previous temperature check operation in the temperature check operation after the second time. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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