Vehicle battery cooling system

Abstract

The present invention provides a vehicle battery cooling system, which drives the battery cooling fan in a manner that makes the driving sound of the battery cooling fan smaller than the driving sound of the blower fan of the air conditioning device without using a transmission signal from the air conditioning device. The vehicle battery cooling system, which cools the battery by supplying air in the vehicle cabin to the battery chamber using the battery cooling fan, comprises: a first temperature sensor, which detects the temperature of the battery; a second temperature sensor, which detects the temperature in the vehicle cabin; and a control device, which controls the driving of the battery cooling fan, the control device estimates the external air temperature outside the vehicle, estimates the output of the blower fan of the vehicle air conditioning device based on the difference between the temperature in the vehicle cabin and the estimated external air temperature, and controls the output of the battery cooling fan based on the estimated output of the blower fan of the air conditioning device and the temperature of the battery.

Description

Technical Field

[0001] The invention relates to a battery cooling system for a vehicle. Background Art

[0002] An electric vehicle or hybrid electric vehicle having a driving motor as a driving force source is equipped with a battery as a power source for the driving motor. It is known that the battery deteriorates due to the heat generated by repeated charging and discharging and the temperature rise caused by the influence of the ambient temperature. Therefore, a system for cooling the battery is installed in the vehicle. As one method of a battery cooling system for a vehicle, there is a system that cools the battery by supplying air in the vehicle compartment to the battery through a cooling fan.

[0003] Here, in the battery cooling system, a technology is proposed to reduce the possibility that the driving sound of the cooling fan becomes noise and is heard by passengers. For example, Patent Documents 1 and 2 disclose the following technology: a control device controls the driving of the cooling fan in such a way that the driving sound of the cooling fan is lower than the driving sound of the blower fan of the air conditioner.

[0004] Prior art literature Patent Literature Patent Document 1: Japanese Patent Application Publication No. 2010-193602 Patent Document 2: Japanese Patent Application Publication No. 2013-216173 Summary of the invention

[0005] Technical issues Here, the battery cooling system of the vehicle is obliged to perform fault diagnosis based on an on-board fault diagnosis device (OBD: On Board Diagnostics, on-board diagnostic system), and components such as sensors and control devices used in the control of the battery cooling system become the objects of fault diagnosis. Components that become the object of fault diagnosis (hereinafter also referred to as "OBD requirement target components") are required to comply with OBD requirements. In the technologies described in the above-mentioned patent documents 1 and 2, when a signal of the output of a blower fan is obtained from an air-conditioning device that is not included in the battery cooling system, the components that detect or calculate the output of the blower fan also become OBD requirement target components, and countermeasures need to be taken.

[0006] The present invention is made in view of the above-mentioned problems, and an object of the present invention is to provide a vehicle battery cooling system that can drive a battery cooling fan in a manner that makes the driving sound of the battery cooling fan smaller than the driving sound of the blower fan of the air conditioning device without using a signal sent from the air conditioning device.

[0007] Technical Solution In order to solve the above-mentioned problems, according to one aspect of the present invention, a vehicle battery cooling system is provided, which uses a battery cooling fan to supply air in the vehicle cabin to a battery room containing the battery to cool the battery, and the vehicle battery cooling system comprises: a first temperature sensor, which detects the temperature of the battery; a second temperature sensor, which detects the temperature in the vehicle cabin; and a control device, which controls the drive of the battery cooling fan, and the control device performs the following processing: an outside air temperature estimation process, which estimates the outside air temperature outside the vehicle; an air conditioning blower fan output estimation process, which estimates the output of the blower fan of the vehicle's air conditioning device based on the difference between the temperature in the vehicle cabin and the estimated outside air temperature; and a battery cooling fan control process, which controls the output of the battery cooling fan based on the estimated output of the blower fan of the air conditioning device and the temperature of the battery.

[0008] Technical Effects As described above, according to the present invention, the battery cooling fan can be driven so that the driving sound of the battery cooling fan is lower than the driving sound of the blower fan of the air conditioner without using a transmission signal from the air conditioner. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 Schematic diagram showing a configuration example of a vehicle battery cooling system according to an embodiment of the present invention.

[0010] Figure 2 It is an explanatory diagram showing the structure of a control mechanism of the battery cooling system according to this embodiment.

[0011] Figure 3 This is a logic diagram for calculating the driving duty ratio of the battery cooling fan in this embodiment.

[0012] Figure 4 This is a flowchart of the processing operation for controlling the driving of the battery cooling fan in this embodiment.

[0013] Figure 5 : is a flowchart of the outside air temperature estimation process in this embodiment.

[0014] Figure 6 This is a flowchart of the reference temperature recording process in this embodiment.

[0015] Figure 7 This is a schematic diagram shown to explain the calculation method of the estimated outside air temperature in this embodiment.

[0016] Figure 8 1 is an explanatory diagram showing an example of a blower fan output estimation map according to the present embodiment.

[0017] Fig. 9It is an explanatory diagram showing changes in indoor temperature after the start-up of the power system.

[0018] Fig.10 This is a flowchart of the indoor temperature acquisition definition process of this embodiment.

[0019] Fig.11 This is a flowchart of a processing operation for controlling the driving of a battery cooling fan according to an application example.

[0020] Explanation of symbols 1: Vehicle 10: Battery Cooling System 20: Battery 22: Battery cooling fan 25: Battery Room 26: Air conditioning unit 27: Blower fan 30: Carriage 32: Cargo Box 40: Air conditioning system 53: Battery temperature sensor 54: Carriage temperature sensor 56: Fan motor 60: Control device 61: Processing Department 63: Storage 71: Outside air temperature estimation unit 73: Air conditioner blower fan output estimation unit 75: Battery cooling fan control unit DETAILED DESCRIPTION

[0021] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that in this specification and the drawings, components having substantially the same functional structure are given the same reference numerals, and repeated descriptions are omitted.

[0022] <1. Overall structure of the battery cooling system> First, refer to Figure 1 , an example of the overall structure of the vehicle battery cooling system according to the embodiment of the present invention is described.

[0023] Figure 1 Schematically shows a vehicle equipped with a vehicle battery cooling system according to the present embodiment. Figure 1 As shown, the vehicle 1 includes a battery 20 , a battery cooling system 10 , and an air conditioning system 40 .

[0024] The battery 20 is a secondary battery that supplies power to a driving motor (not shown) provided as a driving force source of the vehicle 1. The battery 20 is configured to include a plurality of battery cells. The battery 20 may be, for example, a lithium-ion battery rated at 200 V, but the type and rated output of the battery 20 are not particularly limited. The battery 20 is housed in a battery chamber 25.

[0025] The air conditioning system 40 performs air conditioning in the vehicle cabin 30 through the air conditioning device 26. The air conditioning system 40 includes an air conditioning duct 41, an air conditioning device 26, and a blower fan 27. The air conditioning duct 41 is a passage for circulating air, and connects the outside of the vehicle 1 with the inside of the vehicle cabin 30. The air conditioning duct 41 has a first suction port 41a connected to the outside of the vehicle 1, and a second suction port 41b connected to the inside of the vehicle cabin 30. The air conditioning device 26 includes a switching damper 28 provided in the air conditioning duct 41, and a blower fan 27 as an air supply unit arranged on the side closer to the vehicle cabin 30 than the switching damper 28. The switching damper 28 switches the opening and closing states of the first suction port 41a and the second suction port 41b of the air conditioning duct 41. The blower fan 27 is driven by a blower motor not shown.

[0026] If the switch damper 28 closes the first suction port 41a and opens the second suction port 41b while the blower fan 27 is driven, the internal air circulation mode is entered. In the internal air circulation mode, the internal air of the vehicle 1 is introduced into the air conditioning device 26 from the second suction port 41b and blown into the vehicle compartment 30 from the blowout port of the air conditioning device 26. On the other hand, if the switch damper 28 opens the first suction port 41a and closes the second suction port 41b while the blower fan 27 is driven, the external air introduction mode is entered. In the external air introduction mode, the external air is sucked into the air conditioning duct 41 from the first suction port 41a and introduced into the air conditioning device 26, and blown into the vehicle compartment 30 from the blowout port of the air conditioning device 26.

[0027] The air conditioner 26 adjusts the temperature of the air supplied to the interior of the vehicle cabin 30 so that the interior temperature detected by the interior temperature sensor for detecting the temperature in the interior of the vehicle cabin 30 becomes the set temperature. In the present embodiment, the intake air temperature detected by the interior temperature sensor (equivalent to the second temperature sensor) as a component of the battery cooling system 10 is used as the interior temperature detected by the interior temperature sensor. However, the interior temperature sensor for detecting the interior temperature may be provided in the interior of the vehicle cabin 30 independently of the interior temperature sensor of the battery cooling system 10.

[0028] The battery cooling system 10 supplies air in the vehicle cabin 30 to the battery room 25 equipped with the battery 20 by the battery cooling fan 22, thereby cooling the battery 20. The occupant usually adjusts the set temperature of the air conditioner 26 so that the indoor temperature of the vehicle cabin 30 is about 20 to 30°C. The battery cooling system 10 cools the battery 20 by supplying the air in the vehicle cabin 30 whose temperature is adjusted in this way to the battery room 25, thereby preventing the battery 20 from overheating.

[0029] The battery cooling system 10 includes a battery cooling fan 22, a cooling duct 42, and an exhaust duct 44. The cooling duct 42 connects the vehicle cabin 30 with the battery chamber 25. The exhaust duct 44 constitutes an exhaust path connecting the battery chamber 25 with the outside of the vehicle. An exhaust grille 49 is provided in the exhaust duct 44. When the air pressure inside the vehicle becomes high, the exhaust grille 49 opens to discharge air to the outside of the vehicle.

[0030] The battery room 25 is arranged between the cabin 30 and the cargo box 32 at the rear of the vehicle and is arranged near the rear seat 19 arranged in the cabin 30. In the present embodiment, the battery room 25 is arranged below the rear seat 19. The battery cooling fan 22 is arranged in the cooling duct 42. The battery cooling fan 22 is driven by a fan motor (not shown) to supply air in the cabin 30 to the battery room 25.

[0031] Figure 2 1 is an explanatory diagram showing the structure of the control mechanism of the battery cooling system 10. Figure 2 As shown, the battery cooling system 10 includes a battery temperature sensor (first temperature sensor) 53 , a cabin temperature sensor (second temperature sensor) 54 , a fan motor 56 that drives the cooling fan 22 , and a control device (ECU: electronic control unit) 60 .

[0032] The battery temperature sensor 53 detects the temperature T_bt of the battery 20 (hereinafter, also referred to as the battery temperature T_bt). The battery temperature sensor 53 is provided in the battery 20 or the battery chamber 25, and directly or indirectly detects the temperature of the battery 20. The cabin temperature sensor 54 detects the temperature T_ab in the cabin 30 (hereinafter, also referred to as the indoor temperature T_ab). In the present embodiment, the cabin temperature sensor 54 is provided in the cooling duct 42. However, the cabin temperature sensor 54 may be provided in the cabin 30, or may be provided in the battery chamber 25 at a position closer to the cabin 30 than the battery 20.

[0033] The control device 60 is configured to include a processing unit 61 having a processor such as a CPU (Central Processing Unit), a storage unit 63 having a RAM (Random Access Memory) or a ROM (Read Only Memory) connected to the processing unit 61 in a communicable manner, and an input / output interface (not shown). The control device 60 is connected to the battery temperature sensor 53, the vehicle cabin temperature sensor 54, and the fan motor 56 in a communicable manner. The control device 60 controls the output of the battery cooling fan 22 and performs a process of cooling the battery 20.

[0034] <2. Structure of control device> Next, the control device 60 of the battery cooling system 10 will be described in detail.

[0035] The control device 60 functions as a device that executes a process of driving the fan motor 56 and cooling the battery 20 by executing a computer program through one or more processors such as CPUs. The computer program is a computer program for causing the processor to execute the actions to be performed by the control device 60, which will be described later. The computer program executed by the processor may be recorded in a recording medium that functions as a storage unit 63 provided in the control device 60, or may be recorded in a recording medium built into the control device 60 or in any recording medium that can be external to the control device 60.

[0036] The recording medium for recording the computer program may be a magnetic medium such as a hard disk, a floppy disk, and a magnetic tape, an optical recording medium such as a CD-ROM (Compact Disk Read Only Memory), a DVD (Digital Versatile Disk), and Blu-ray (registered trademark), a magneto-optical medium such as a magneto-optical disk, a storage element such as a RAM (Random Access Memory) and a ROM (Read Only Memory), a flash memory such as a USB (Universal Serial Bus) memory and an SSD (Solid State Drive), or other medium capable of storing a program.

[0037] like Figure 2As shown, the processing unit 61 of the control device 60 includes an outside air temperature estimation unit 71, an air conditioner blower fan output estimation unit 73, and a battery cooling fan control unit 75. The outside air temperature estimation unit 71, the air conditioner blower fan output estimation unit 73, and the battery cooling fan control unit 75 are functions realized by the processor executing the program. However, a part of the outside air temperature estimation unit 71, the air conditioner blower fan output estimation unit 73, and the battery cooling fan control unit 75 may also be a structure including hardware such as an analog circuit.

[0038] The outside air temperature estimation unit 71 performs an outside air temperature estimation process for estimating the outside air temperature outside the vehicle. That is, the battery cooling system 10 has a configuration that estimates the outside air temperature by calculation rather than acquiring a sensor signal from a temperature sensor for detecting the outside air temperature provided in the vehicle 1, thereby being able to utilize information on the outside air temperature without adding an OBD target component.

[0039] The air conditioner blower fan output estimation unit 73 performs an air conditioner blower fan output estimation process in which the air conditioner blower fan output estimation unit 73 estimates the output of the blower fan 27 of the air conditioner 26 based on the difference between the room temperature T_ab and the estimated outside air temperature (hereinafter, also referred to as "estimated outside air temperature T_am"). That is, the battery cooling system 10 has a configuration in which the output of the blower fan 27 is estimated by calculation instead of acquiring the output information of the blower fan 27 from the air conditioner 26 of the air conditioning system 40, thereby being able to use the output information of the blower fan 27 without increasing the OBD target components.

[0040] The battery cooling fan control unit 75 executes a battery cooling fan control process in which the battery cooling fan control unit 75 controls the output of the battery cooling fan 22 based on the estimated output of the blower fan 27 and the battery temperature T_bt. This can suppress overheating of the battery 20 and suppress degradation of the battery 20.

[0041] <3. Processing Action> Next, the processing operation of controlling cooling of battery 20 by control device 60 will be described.

[0042] Figure 3 and Figure 4 It is an explanatory diagram showing the processing operation performed by the processing unit 61 of the control device 60. Figure 3 1 is a logic diagram showing the operation of the driving duty ratio D_bf of the battery cooling fan 22. Figure 4 The flowchart shows the processing operation for controlling the driving of the battery cooling fan 22 .

[0043] First, when the battery cooling system 10 is started (step S11), the outside air temperature estimating unit 71 of the processing unit 61 performs a process of estimating the outside air temperature (step S13). In the present embodiment, the outside air temperature estimating unit 71 calculates the estimated outside air temperature T_am based on the battery temperature (reference temperature) T_bt_off detected at a predetermined time when the electric system including the battery 20 is in a stopped state, the battery temperature (start-up temperature) T_bt_on when the electric system is started, and the elapsed time Ti_s from the predetermined time when the reference temperature T_bt_off is detected until the time when the start-up temperature T_bt_on is detected. The outside air temperature estimation process is a process of estimating the outside air temperature based on the change in the battery temperature T_bt during the stop of the electric system, and the outside air temperature estimating unit 71 calculates the estimated outside air temperature T_am using only the components of the battery cooling system 10.

[0044] Figure 5 A flowchart of the outside air temperature estimation process is shown.

[0045] First, the outside air temperature estimation unit 71 reads the reference temperature T_bt_off recorded in the storage unit 63 (step S31). The reference temperature T_bt_off is the battery temperature T_bt detected by the battery temperature sensor 53 during the period from the last power system stop to the current power system start, and is recorded in the storage unit 63 together with information on the time when the battery temperature T_bt was detected. The reference temperature T_bt_off is detected at least once during the period from the last power system stop to the current power system start.

[0046] However, if the time from the time when the reference temperature T_bt_off is detected until the power system is started becomes too long, the outside air temperature rises and falls repeatedly during this period, and the calculation accuracy of the estimated outside air temperature T_am based on the battery temperature T_bt may decrease. Therefore, in the present embodiment, the outside air temperature estimation unit 71 detects the battery temperature T_bt at predetermined intervals during the period from the last power system stop to the current power system start, and records it in the storage unit 63 together with the time when the battery temperature T_bt is detected.

[0047] Figure 6 A flowchart of the reference temperature recording process is shown. Figure 6 The flowchart shown can be executed during the operation of the power system including the battery 20, or can be executed when it is determined that Figure 4 The flowchart shown is started when the battery cooling system 10 is stopped (step S23 / Yes).

[0048] First, the outside air temperature estimation unit 71 determines whether the power system including the battery 20 has stopped (step S41). The outside air temperature estimation unit 71 may determine whether the battery cooling system 10 has stopped instead of determining whether the power system has stopped. In this case, step S41 may be replaced by Figure 4 Step S23 of the flowchart shown.

[0049] When it is not determined that the power system is stopped (S41 / No), the outside air temperature estimation unit 71 repeats the determination of step S41. On the other hand, when it is determined that the power system is stopped (S41 / Yes), the outside air temperature estimation unit 71 obtains the battery temperature T_bt detected by the battery temperature sensor 53 and records it as the reference temperature T_bt_off in the storage unit 63 together with the time when the battery temperature T_bt is detected (step S43).

[0050] Next, the outside air temperature estimation unit 71 determines whether a predetermined time has passed since the moment when the reference temperature T_bt_off was recorded in the previous step S43 (step S45). The predetermined time is set to, for example, 4 hours, but it can also be set to any time. However, if the predetermined time is too long, when the time until the next power system startup becomes long, the battery temperature T_bt repeatedly rises and falls due to the influence of the outside air temperature, and it is difficult to calculate the estimated outside air temperature T_am based on the change in the battery temperature T_bt and the elapsed time Ti_s. Therefore, the predetermined time is set to a time that is appropriate in consideration of the accuracy of the estimated outside air temperature T_am calculated based on the change in the battery temperature T_bt and the elapsed time Ti_s.

[0051] When the outside air temperature estimation unit 71 does not determine that the predetermined time has passed since the time when the reference temperature T_bt_off was recorded (S45 / No), the outside air temperature estimation unit 71 proceeds to step S49. On the other hand, when it is determined that the predetermined time has passed since the time when the reference temperature T_bt_off was recorded (S45 / Yes), the outside air temperature estimation unit 71 obtains the battery temperature T_bt detected by the battery temperature sensor 53, and updates the information recorded in the storage unit 63 as the reference temperature T_bt_off together with the time when the battery temperature T_bt was detected (step S47).

[0052] Next, the outside air temperature estimation unit 71 determines whether the power system has been started (step S49). If it is not determined that the power system has been started (S49 / No), the outside air temperature estimation unit 71 returns to step S45 and repeatedly determines the elapse of a predetermined time (step S45) and updates the reference temperature T_bt_off (step S47). On the other hand, if it is determined that the power system has been started (S49 / Yes), the outside air temperature estimation unit 71 ends the process of recording the reference temperature.

[0053] Return to Figure 5 After the outside air temperature estimation unit 71 reads the reference temperature T_bt_off in step S31, it obtains the battery temperature (start-up temperature) T_bt_on detected by the battery temperature sensor 53 when the power system is started this time (step S33). Next, the outside air temperature estimation unit 71 calculates the elapsed time Ti_s from the time when the reference temperature T_bt_off is detected to the time when the start-up temperature T_bt_on is detected (step S35).

[0054] Next, the outside air temperature estimation unit 71 calculates the estimated outside air temperature T_am based on the reference temperature T_bt_off, the startup temperature T_bt_on, and the elapsed time Ti_s (step S37). Specifically, the outside air temperature estimation unit 71 uses the reference temperature T_bt_off, the startup temperature T_bt_on, and the elapsed time Ti_s as input information, and calculates the estimated outside air temperature T_am based on the outside air temperature estimation map pre-stored in the storage unit 63.

[0055] Figure 7 This is a schematic diagram shown to explain a method of calculating the estimated outside air temperature T_am.

[0056] When the outside air temperature is lower than the battery temperature T_bt, the battery temperature T_bt also gradually decreases while the vehicle 1 is stopped. The rate of decrease of the battery temperature T_bt (the amount of change in the battery temperature T_bt over time) at this time depends on the battery temperature T_bt and the outside air temperature. That is, if the battery temperature T_bt and the rate of decrease of the battery temperature T_bt thereafter are known, the outside air temperature can be estimated.

[0057] like Figure 7As shown in FIG. 1 , when the elapsed time Ti_s from the time when the electric system is stopped (SW-OFF) is short and the difference between the battery temperature T_bt and the outside air temperature is relatively large, the rate of decrease of the battery temperature T_bt becomes relatively large. Thereafter, as the elapsed time Ti_s from the time when the electric system is stopped (SW-OFF) is longer, the difference between the battery temperature T_bt and the outside air temperature becomes smaller, and the rate of decrease of the battery temperature T_bt becomes relatively small.

[0058] During the startup of the electric system, the battery temperature T_bt is cooled by the battery cooling system 10. Therefore, the battery temperature T_bt when the electric system is stopped (SW-off) is maintained at a temperature lower than, for example, 35 to 40° C. Therefore, for the battery temperature T_bt lower than, for example, 35 to 40° C., the rate of decrease of the battery temperature T_bt corresponding to each outside air temperature can be obtained in advance by measuring using an actual device or by simulation, so that an outside air temperature estimation map can be prepared.

[0059] In this way, the outside air temperature estimation unit 71 determines the outside air temperature according to Figure 5 The flowchart shown in the figure executes the outside air temperature estimation process. Thus, the outside air temperature estimation unit 71 can calculate the estimated outside air temperature T_am using the components of the battery cooling system 10 without acquiring a signal indicating the outside air temperature from other sensors or systems such as the outside air temperature sensor.

[0060] Back to Figure 4 After the estimated outside air temperature T_am is calculated in step S13, the air conditioner blower fan output estimation unit 73 obtains information on the indoor temperature T_ab detected by the cabin temperature sensor 54 (step S15). In the present embodiment, the air conditioner blower fan output estimation unit 73 obtains information on the temperature detected by the cabin temperature sensor 54 provided in the cooling duct 42.

[0061] Next, the air conditioning blower fan output estimation unit 73 estimates the driving duty ratio D_br of the blower fan 27 of the air conditioning device 26 (step S17). The blower fan 27 controls the output by adjusting the ratio of the power-on time for each predetermined time period, that is, the driving duty ratio D_br. The air conditioning device 26 adjusts the indoor temperature T_ab to the set temperature by supplying temperature-regulated air into the vehicle compartment 30 using the blower fan 27. The greater the difference between the outside air temperature and the indoor temperature T_ab, the greater the output of the blower fan 27, so that the indoor temperature T_ab becomes the set temperature as early as possible. Therefore, the air conditioning blower fan output estimation unit 73 uses the estimated outside air temperature T_am and the indoor temperature T_ab as input information, and calculates the driving duty ratio D_br of the blower fan 27 according to the blower fan output estimation map pre-stored in the storage unit 63.

[0062] Figure 8 It is an explanatory diagram showing an example of a blower fan output estimation map.

[0063] application Figure 8 The blower fan output estimation map shown in the example shows that the blower fan 27 is operated when the outside air temperature is equal to the room temperature multiplied by a predetermined coefficient (in Figure 8 In the case where the outside air temperature is lower than the minimum output temperature line L1, the air conditioner 26 operates as a heating function, and the greater the difference between the outside air temperature and the indoor temperature, the greater the output of the blower fan 27. On the other hand, when the outside air temperature exceeds the minimum output temperature line L1, the air conditioner 26 operates as a cooling function, and the greater the difference between the outside air temperature and the indoor temperature, the greater the output of the blower fan 27. Therefore, it is possible to pre-produce a blower fan output estimation map based on information for setting the drive duty ratio D_br of the blower fan 27.

[0064] In this way, the air-conditioner blower fan output estimation unit 73 can calculate the drive duty ratio D_br of the blower fan 27 using the components of the battery cooling system 10 without acquiring a signal indicating the output of the blower fan 27 from the air-conditioning device 26 .

[0065] Back to Figure 4 After estimating the driving duty ratio D_br of the blower fan of the air conditioner 26 in step S17, the battery cooling fan control unit 75 sets the driving duty ratio D_bf of the battery cooling fan 22 (step S19). The battery cooling fan control unit 75 sets the driving duty ratio D_bf of the battery cooling fan 22 based on the estimated driving duty ratio D_br of the blower fan 27 and the battery temperature T_bt so that the driving sound of the battery cooling fan 22 will not become an abnormal sound and be heard by the occupants. At this time, the battery cooling fan control unit 75 sets the maximum driving duty ratio D_bf within the range in which the driving sound of the battery cooling fan 22 will not become an abnormal sound and be heard by the occupants. The battery cooling fan 22 controls the output by adjusting the driving duty ratio D_bf, which is the ratio of the power-on time for each predetermined time period.

[0066] In the present embodiment, the driving sound of the battery cooling fan 22 is controlled in such a manner that the occupants cannot easily hear the driving sound of the battery cooling fan 22, taking into account not only the driving sound of the blower fan 27 of the air conditioner 26 but also the driving sound of the engine of the vehicle 1, the wind noise accompanying the running of the vehicle 1, and the background noise such as the road noise caused by the friction between the tires and the road surface. Specifically, the battery cooling fan control unit 75 receives the battery temperature T_bt detected by the battery temperature sensor 53, the vehicle speed V detected by the vehicle speed sensor (not shown), the output torque or target torque Tq_EG of the engine, and the driving duty ratio D_br of the blower fan 27 as input information, and calculates the driving duty ratio D_bf of the battery cooling fan 22 based on the cooling fan output setting map pre-stored in the storage unit 63.

[0067] The higher the battery temperature T_bt is, the greater the difference from the target battery temperature is, and the more necessary it is to cool the battery 20, so the driving duty ratio D_bf of the battery cooling fan 22 is set to a larger value. The faster the vehicle speed V is, the greater the wind noise and road noise are, and the greater the background noise is, so the driving duty ratio D_bf of the battery cooling fan 22 can be set to a larger value. The greater the output torque or target torque Tq_EG of the engine is, the greater the driving sound of the engine is, so the driving duty ratio D_bf of the battery cooling fan 22 can be set to a larger value.

[0068] The information of the vehicle speed V and the output torque or target torque Tq_EG of the engine is included in the information acquired by the electric system as information for controlling the charge and discharge of the electric system including the battery 20. Therefore, when constructing the battery cooling system 10, no new OBD target component is added.

[0069] In addition, in order to consider the difficulty of the background noise generated by the vehicle 1 as it travels to be heard by the passengers in the vehicle cabin 30, the cooling fan output setting map may also include information on the degree of opening and closing of the side windows as input information. In addition, when the vehicle 1 is an electric vehicle without an engine, the cooling fan output setting map may also be a map that does not include information such as the output torque of the engine.

[0070] Next, the battery cooling fan control unit 75 controls the driving of the fan motor 56 of the battery cooling fan 22 based on the set driving duty ratio D_bf (step S21). Next, the battery cooling fan control unit 75 determines whether the battery cooling system 10 has stopped (step S23). If it is not determined that the battery cooling system 10 has stopped (S23 / No), the process returns to step S13 and repeatedly executes the processing of each step described so far. On the other hand, if it is determined that the battery cooling system 10 has stopped (S23 / Yes), the battery cooling fan control unit 75 ends the process of cooling the battery 20.

[0071] As described above, the battery cooling system 10 of the present embodiment does not use the transmission signal from the air conditioning device 26, but controls the driving of the battery cooling fan 22 in such a manner that the driving sound of the battery cooling fan 22 audible to the occupants is lower than the driving sound of the blower fan 27 of the air conditioning device 26. Specifically, the control device 60 estimates the outside air temperature based on the time change of the battery temperature T_bt. In addition, the control device 60 estimates the driving duty ratio D_br of the blower fan 27 based on the estimated outside air temperature T_am and the indoor temperature T_ab. Therefore, the driving of the battery cooling fan 22 can be controlled without setting the air conditioning device 26, the outside air temperature sensor for detecting the outside air temperature, or the sunlight sensor as the OBD target components to be the object of the fault diagnosis of the battery cooling system 10. As a result, the OBD target components of the battery cooling system 10 can be reduced.

[0072] In addition, the battery cooling system 10 of the present embodiment updates the reference temperature T_bt_off of the battery 20 detected when the electric system is in a stopped state and used in the calculation of the estimated outside air temperature T_am at predetermined intervals. Therefore, it is possible to suppress the decrease in the accuracy of the estimated outside air temperature T_am estimated based on the reference temperature T_bt_off and the rate of decrease of the battery temperature T_bt, and it is possible to reduce the possibility that the driving sound of the battery cooling fan 22 becomes an abnormal sound and is heard by the occupants.

[0073] <4. Application Examples> Next, application examples of the above-described embodiment will be described.

[0074] It takes a predetermined time until the temperature in the vehicle cabin 30 is stabilized by the operation of the air conditioning system 40 after the occupant starts using the vehicle 1. When the battery cooling fan control process is executed while the indoor temperature T_ab is unstable, the output of the blower fan 27 estimated using the indoor temperature T_ab may fluctuate, resulting in the possibility that the output of the battery cooling fan 22 set may fluctuate. Therefore, the battery cooling system of the application example does not start the definition of the indoor temperature T_ab used for estimating the output of the blower fan 27 until the indoor temperature T_ab is stabilized, and starts the definition of the indoor temperature T_ab after the indoor temperature T_ab is stabilized.

[0075] “Definition of start indoor temperature T_ab” indicates processing for using indoor temperature T_ab detected by vehicle interior temperature sensor 54 to estimate the output of blower fan 27 of air conditioner 26 .

[0076] Fig. 9 and Fig.10 It is an explanatory diagram showing a room temperature definition start process performed by the battery cooling system of the application example. Fig. 9 is an explanatory diagram showing changes in the indoor temperature T_ab after the electric system including the battery 20 is started (SW-ON), Fig.10 A flowchart showing the indoor temperature acquisition definition process.

[0077] When the electric system is activated (step S51 ), the air-conditioner blower fan output estimation unit 73 acquires the indoor temperature T_ab detected by the vehicle interior temperature sensor 54 (step S53 ). The indoor temperature T_ab is acquired at a predetermined sampling period set in advance.

[0078] Next, the air conditioner blower fan output estimation unit 73 calculates the change rate dT_ab / dt of the indoor temperature T_ab based on the indoor temperature T_ab acquired in the previous sampling cycle, the indoor temperature T_ab acquired in the current sampling cycle, and the time interval dt of the sampling cycles (step S55). The air conditioner blower fan output estimation unit 73 calculates the change rate dT_ab / dt of the indoor temperature T_ab by dividing the difference dT_ab obtained by subtracting the indoor temperature T_ab acquired in the previous sampling cycle from the indoor temperature T_ab acquired in the current sampling cycle by the time interval dt.

[0079] When the indoor temperature T_ab is first acquired after the power system is started, the air conditioner blower fan output estimation unit 73 omits step S55 and the next step S57 and returns to step S53 because the change rate dT_ab / dt of the indoor temperature T_ab cannot be calculated.

[0080] Next, the air conditioner blower fan output estimation unit 73 determines whether the change rate dT_ab / dt of the indoor temperature T_ab is less than a predetermined threshold value set in advance (step S57). In order to determine whether the indoor temperature T_ab is stable, the predetermined threshold value can be set to any appropriate value. In the case where it is not determined that the change rate dT_ab / dt of the indoor temperature T_ab is less than the predetermined threshold value (S57 / No), the air conditioner blower fan output estimation unit 73 returns to step S53, and repeatedly obtains the indoor temperature T_ab (step S53) and determines the change rate dT_ab / dt of the indoor temperature T_ab (steps S55 to S57) ( Figure 5 The indoor temperature defines the shutdown period).

[0081] On the other hand, when it is determined that the change rate dT_ab / dt of the indoor temperature T_ab is less than the predetermined threshold value (S57 / Yes), the air conditioner blower fan output estimation unit 73 starts defining the indoor temperature T_ab (step S59). Thus, the air conditioner blower fan output estimation unit 73 ends the indoor temperature definition start processing. Thereafter, the air conditioner blower fan output estimation unit 73 starts estimating the output of the blower fan 27 of the air conditioner 26 using the information of the indoor temperature T_ab (step S59). Figure 5 The indoor temperature defines the start of the period).

[0082] Fig.11 1 is a flowchart showing a processing operation of controlling the driving of the battery cooling fan 22 by the battery cooling system of the application example.

[0083] In the application example, after the estimated outside air temperature T_am is calculated in step S13, the air conditioner blower fan output estimation unit 73 determines whether the definition of the indoor temperature T_ab has started (step S61). When it is determined that the definition of the indoor temperature T_ab has started (S61 / Yes), the air conditioner blower fan output estimation unit 73 proceeds to step S15, and the processing unit 61 controls the driving of the battery cooling fan 22 according to the sequence described in the above embodiment.

[0084] On the other hand, when it is determined that the definition of the indoor temperature T_ab has not been started (S61 / No), the air conditioner blower fan output estimation unit 73 proceeds to step S19 and sets the drive duty ratio D_bf of the battery cooling fan 22 to a predetermined minimum value (step S19). Then, the battery cooling fan control unit 75 controls the drive of the battery cooling fan 22 at the minimum drive duty ratio D_bf (step S21).

[0085] Thus, in the application example, the battery cooling fan 22 is controlled at the lowest driving duty ratio D_bf during the period from when the battery cooling system 10 is activated until the indoor temperature T_ab detected by the cabin temperature sensor 54 stabilizes. Therefore, it is possible to prevent the output of the battery cooling fan 22 from fluctuating due to the output fluctuation of the blower fan 27 of the air conditioner 26 estimated using the indoor temperature T_ab.

[0086] The preferred embodiment of the present invention is described in detail with reference to the accompanying drawings, but the present invention is not limited to this example. A person having ordinary knowledge in the technical field to which the present invention belongs knows that various variations or modifications can be thought of within the scope of the technical concept described in the claims, and understands that these variations or modifications also belong to the technical scope of the present invention.

Claims

1. A battery cooling system for a vehicle, characterized in that: The battery cooling system for a vehicle supplies air in a vehicle cabin to a battery room containing a battery by a battery cooling fan to cool the battery. The battery cooling system for a vehicle comprises: a first temperature sensor, which detects the temperature of the battery; a second temperature sensor for detecting the temperature in the vehicle compartment; and a control device for controlling the driving of the battery cooling fan, The control device performs the following processing: External air temperature estimation processing, estimating the external air temperature outside the vehicle; an air conditioning blower fan output estimation process of estimating an output of a blower fan of an air conditioning device of the vehicle based on a difference between the temperature in the vehicle cabin and the estimated outside air temperature; as well as The battery cooling fan control process controls the output of the battery cooling fan based on the estimated output of the blower fan of the air conditioner and the temperature of the battery.

2. The vehicle battery cooling system according to claim 1, characterized in that: The control device estimates the outside air temperature based on the temperature of the battery.

3. The vehicle battery cooling system according to claim 2, characterized in that: The control device estimates the outside air temperature based on a reference temperature, a startup temperature, and an elapsed time from a predetermined time when the reference temperature is detected until a time when the startup temperature is detected, wherein the reference temperature is the temperature of the battery detected at the predetermined time when the power system including the battery is in a stopped state, and the startup temperature is the temperature of the battery when the power system is started.

4. The vehicle battery cooling system according to claim 3, characterized in that: The control device detects the temperature of the battery at predetermined intervals after the electric power system is stopped, and records the battery temperature as the reference temperature together with the time when the battery temperature is detected for use in estimating the outside air temperature.

5. The vehicle battery cooling system according to claim 1, characterized in that: After the electric system including the battery is started and the rate of change of the temperature in the vehicle cabin becomes less than a predetermined threshold, the control device starts the battery cooling fan control process based on the estimated output of the blower fan of the air conditioner and the temperature of the battery.

Images