JP2016201250A - Cooling system for on-vehicle secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently secure an opportunity of detecting the presence or absence of abnormality of a cooling fan while suppressing overheat or over-cooling of a secondary battery.SOLUTION: An on-vehicle secondary battery cooling system includes a cooling fan 40. The cooling fan 40 is subject to driving control based on variable control in which a driving instruction value is changed according to a battery temperature TB or first constant control in which the driving instruction value is fixed to a first instruction value. Abnormality detection processing for detecting the presence or absence of abnormality of the cooling fan 40 is performed on the basis of the actual rotation speed of the cooling fan 40 under the first constant control. In this system, when variation of the driving instruction value in the variable control increases to a predetermined amount Th or more while a predetermined condition for executing the first constant control has not been established since the actuation start time of a vehicle and thus only the variable control is being executed, the variable control is switched to second constant control in which the instruction value is fixed to the value Dof an average area of the varying driving instruction value, and abnormality detection processing is executed under the second constant control.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a cooling system for cooling a secondary battery for driving a hybrid vehicle.

  The hybrid vehicle is equipped with a secondary battery (battery) that stores electric energy for driving the vehicle. The temperature of the secondary battery increases with charge / discharge due to its internal resistance. Therefore, it has been conventionally proposed to provide a cooling fan around the secondary battery and forcibly air-cool the secondary battery with this cooling fan.

  For example, Patent Document 1 discloses a cooling device for vehicle electrical components in which a cooling fan is provided in the vicinity of a secondary battery. In this cooling device, the command duty of the cooling fan is changed according to the temperature of the high-voltage secondary battery or on-vehicle charger that is the cooling target. That is, the drive control of the cooling fan is performed by variable control. In addition, this cooling device detects the presence or absence of a failure of the cooling fan, and performs diagnosis output when a failure occurs, that is, causes the failure diagnosis function unit of the control unit to record failure information. Furthermore, this cooling device changes the control of the electrical component according to the content of the failure.

JP 2010-158964 A

  By the way, as one method for determining whether or not the cooling fan is abnormal, there is a method using a detection parameter such as the actual number of revolutions of the cooling fan. For example, an abnormality of the cooling fan is determined by comparing the command rotational speed to the cooling fan with the actual rotational speed.

  It is desirable to determine whether there is such an abnormality in a steady state where the cooling fan is driven stably. This is because if the driving state of the cooling fan (fan rotation speed, etc.) fluctuates greatly, the actual rotation speed may deviate from the command rotation speed due to a control delay, etc. Because there is.

  In order to stabilize the driving of the cooling fan, it is conceivable that the cooling fan is driven at a constant duty (constant rotational speed) without changing the command duty (command rotational speed). However, when the cooling fan is driven at a constant duty, naturally, it is difficult to cool the secondary battery following the temperature of the secondary battery. As a result, the rotation speed is insufficient and the secondary battery cannot be sufficiently cooled, resulting in overheating of the secondary battery, or conversely, the rotation speed is excessive and the secondary battery may be overcooled (overcooled).

  Thus, from the viewpoint of temperature management of the secondary battery, the conditions under which constant control can be performed are limited, and therefore the chances of abnormality detection are also limited. Therefore, an object of the present invention is to sufficiently secure an opportunity for detecting the presence or absence of an abnormality of a cooling fan while suppressing overheating or overcooling of a secondary battery.

  The present invention relates to a cooling system for cooling a secondary battery for driving a vehicle mounted on a hybrid vehicle. The system includes a cooling fan that blows cooling air to the secondary battery, and a temperature sensor that detects a battery temperature that is a temperature of the secondary battery. The cooling fan is driven and controlled by variable control in which a drive command value is changed according to the battery temperature, or by first constant control in which the drive command value is fixed to a first command value. During the constant control, an abnormality detection process is performed for detecting whether or not the cooling fan is abnormal based on the actual rotational speed of the cooling fan. In the system, when a predetermined condition for executing the first constant control is not satisfied from the time of starting the vehicle and only the variable control is executed, the drive command value fluctuates in the variable control. When the amount exceeds a predetermined amount, the variable control is switched to the second constant control in which the command value is fixed to the value of the average range of the drive command value that fluctuates, and the abnormality detection process is performed during the second constant control. Is executed.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to ensure the opportunity of detecting the presence or absence of abnormality of a cooling fan, suppressing the overheating or overcooling of a secondary battery.

It is a systematic diagram which shows the structure of the cooling system of the vehicle-mounted secondary battery in embodiment of this invention. It is explanatory drawing of duty control. It is a graph which shows the rotation speed of the cooling fan with respect to instruction | command duty. It is a duty map for determining a command duty. It is a flowchart which shows operation | movement of the cooling system of the vehicle-mounted secondary battery in embodiment of this invention. It is a flowchart explaining the fan fixed duty control of the flowchart shown in FIG. It is a time chart explaining the abnormality detection process flow in case the battery temperature at the time of starting is more than 2nd temperature T1. It is a time chart explaining the abnormality detection process flow during EV driving. It is a flowchart which shows other embodiment of the cooling system of a vehicle-mounted secondary battery.

<System configuration of electric vehicle>
Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, a system configuration of the hybrid vehicle 90 on which the in-vehicle secondary battery cooling system 80 of the present embodiment is mounted will be described. In addition, the dashed-dotted line in FIG. 1 shows a signal line.

  The hybrid vehicle 90 is a hybrid vehicle that uses various types of power sources (the motor generators 16 and 18 and the engine 20) to drive the wheels 26. The main battery 10 for driving the vehicle is connected to the positive and negative input terminals of the system main relay 13 by a positive bus bar 11a and a negative bus bar 12a. The main battery 10 is a chargeable / dischargeable secondary battery such as a nickel metal hydride battery or a lithium ion battery.

  The plus side output terminal and the minus side output terminal of the system main relay 13 are connected to the boost converter 14 by the plus side and minus side bus bars 11b and 12b, respectively. The positive and negative output terminals of the boost converter 14 are connected to the positive and negative input terminals of the inverter 15. Three output bus bars of U phase, V phase, and W phase are connected to the inverter 15, and each output bus bar is connected to an input terminal of each phase of the first and second motor generators 16, 18.

  The output shafts of the motor generators 16 and 18 are connected to a power distribution mechanism 22 using a planetary gear device or the like. The output shaft of the engine 20 is also connected to the power distribution mechanism 22. The output shaft of the power distribution mechanism 22 drives the wheels 26 via the gear mechanism 25 and the axle 24. A vehicle speed sensor 65 that detects the vehicle speed from the rotational speed is attached to the axle 24.

  A plus-side bus bar 51 and a minus-side bus bar 52 are branched from the plus-side bus bar 11a and the minus-side bus bar 12a connected to the main battery 10 as power branch paths, respectively. Each bus bar 51, 52 is connected to a charger 54 that converts power from an external AC power source into charging power for charging the main battery 10 via a charging relay 53.

  A connector 55 (so-called inlet) is connected to the charger 54. This connector 55 can be connected to a connector 101 (so-called charging plug) of an AC power source 102 (for example, commercial power source). The main battery 10 can be charged by the AC power source 102 by connecting the connector 101 to the connector 55. A connector 56 to which the connector 103 of the external DC power source 104 can be connected is also connected to the positive and negative bus bars 51 and 52. Thereby, the main battery 10 can also be charged by the external DC power source 104.

  A DC / DC converter 33 (step-down converter) is also connected to the plus side and minus side bus bars 11b and 12b to which the plus side output terminal and the minus side output terminal of the system main relay 13 to which the main battery 10 is connected are respectively connected. Has been.

  The output of the DC / DC converter 33 is connected to an auxiliary battery 36. The DC / DC converter 33 steps down the voltage of the main battery 10 to an auxiliary voltage such as 12V or 24V, for example. 36 is charged.

  A cooling fan 40 is connected to the auxiliary battery 36. The cooling fan 40 is constituted by an electric cooling fan and blows cooling air to the main battery 10. The cooling fan 40 includes a fan main body 41 in which an impeller is stored, a motor 44 that drives the impeller, and a control unit 45 that controls the speed of the motor 44.

  A suction duct 46 that sucks cooling air is connected to the suction port 42 of the fan main body 41, and a connection duct 47 that supplies cooling air to the casing 48 that houses the main battery 10 is connected to the discharge port 43 of the fan main body 41. It is connected. An exhaust duct 49 for exhausting air that has cooled the main battery 10 is attached to the casing 48.

  An ignition switch 27 is provided in the vehicle interior of the hybrid vehicle 90. The ignition switch 27 is a switch that receives an instruction to start and stop the hybrid vehicle 90 from the user. In addition, a navigation system 30 that detects the current position of the hybrid vehicle 90 or provides route guidance to the destination is also provided in the passenger compartment. The control unit 70 estimates the gradient Inc of the current position based on the route information provided from the navigation system 30.

  Further, as an instrument related to the main battery 10, a temperature sensor 61 for detecting a temperature (hereinafter referred to as “battery temperature TB”) is attached to the main battery 10. Only one temperature sensor 61 may be provided, or a plurality of temperature sensors 61 may be provided at a plurality of locations of the main battery 10. When a plurality of temperature sensors 61 are provided, a statistical value of detection values of the plurality of temperature sensors 61, for example, an average value, a minimum value, a maximum value, or the like is handled as the battery temperature TB.

  A voltage sensor 62 for detecting the voltage VB of the main battery 10 is connected between the positive and negative bus bars 11a, 12a connected to the main battery 10. In addition, a current sensor 63 that detects a charge / discharge current IB of the main battery 10 is attached to the plus side bus bar 11 a between the main battery 10 and the system main relay 13.

  A rotation speed sensor 64 that detects the rotation speed of the motor 44 is attached to the cooling fan 40, and a temperature sensor 66 that detects the intake air temperature is attached to the suction duct 46.

  Control unit 70 calculates the SOC based on detected voltage VB, current IB, battery temperature TB, and the like. Then, control unit 70 controls driving of motor generators 16 and 18 and engine 20 so that the SOC does not fall below a predetermined lower limit threshold and does not exceed a predetermined upper limit threshold.

  As shown in FIG. 1, the control unit 45 of the cooling fan 40 is connected to the control unit 70. The cooling fan 40 is driven by a command from the control unit 70 via the control unit 45. An ignition switch 27, temperature sensors 61 and 66, a voltage sensor 62, a current sensor 63, a rotation speed sensor 64, and a vehicle speed sensor 65 are also connected to the control unit 70, and a Ready-ON signal and a Ready-OFF signal of the ignition switch 27 are connected. The detection signals of the sensors 61 to 66 are input to the control unit 70. In addition, signals such as the accelerator opening Acc and the brake depression amount are also input to the control unit 70.

  The control unit 70 is a computer that includes a CPU 71 that performs arithmetic processing and signal processing, and a memory 72 that stores control data, a control map, a program, and the like. Further, the control unit 70 indicates an on / off signal indicating whether the engine 20 is operating or stopped from another control device, and whether or not the connectors 55 and 56 are connected to the external connectors 101 and 103. A signal or the like is also input.

<Basic operation of hybrid vehicle>
The basic operation of the hybrid vehicle 90 configured as described above will be briefly described. When the hybrid vehicle is Ready-ON, the system main relay 13 is turned on, and the DC power of the main battery 10 is supplied from the inverter 15 to the motor generators 16 and 18 via the boost converter 14.

  Here, Ready-ON indicates a vehicle starting state. The vehicle start state generally refers to a state in which the vehicle is switched from a travel disable state to a travel enable state. The hybrid vehicle 90 is further expanded to include a state where the power supply system of the hybrid vehicle 90 is started up, that is, a state where the control unit 70 (ECU) is activated is included in the Ready-On or vehicle start state. Specifically, when the ignition switch 27 is turned on by the user, when the control unit 70 is activated by an external charging operation, and when the control unit 70 is automatically activated at the reserved time according to the reservation start function Etc. may be included in Ready-ON (vehicle start state).

  When the vehicle starts to travel, the first motor generator 16 is started and the engine 20 is started while the hybrid vehicle 90 is stopped. That is, the engine 20 is cranked by the first motor generator 16.

  The output of the engine 20 is distributed by a power distribution mechanism 22, a part of the output drives the first motor generator 16, and the remaining output is a power distribution mechanism together with the output of the second motor generator 18 functioning as a motor. 22 and the wheel 26 is rotated.

  At this time, the first motor generator 16 functions as a generator, and the generated AC power is consumed as drive power for the second motor generator 18. At the same time, the main battery 10 supplies required power to the second motor generator 18 by discharging.

  On the other hand, when the generated power of the first motor generator 16 is larger than the required power of the second motor generator 18, the surplus AC power generated is converted into DC by the inverter 15 and then charged to the main battery 10.

  When the hybrid vehicle 90 decelerates, the second motor generator 18 functions as a generator to reduce the rotation of the wheels 26 (dynamic braking). The AC power generated at this time is converted into DC power by the inverter 15 and charged to the main battery 10.

  Examples of the travel mode of the hybrid vehicle 90 include a torque conversion travel mode, a charge / discharge travel mode, an EV travel mode, and an engine direct torque travel mode.

  In the torque conversion travel mode, the operation of the engine 20 is controlled so that power corresponding to the required power is output from the engine. Further, the motor generators 16 and 18 are driven and controlled so that all of the power output from the engine 20 is torque-converted by the power distribution mechanism 22 and the motor generators 16 and 18 and output to the drive shaft.

  In the charge / discharge travel mode, the engine 20 is operated and controlled so that power corresponding to the sum of the required power and the power required for charging / discharging the main battery 10 is output from the engine 20. Further, torque conversion by the power distribution mechanism 22 and the motor generators 16 and 18 causes a part of the power output from the engine 20 to be distributed to the charge / discharge of the main battery 10 and the remaining part to be distributed to the drive shaft. In addition, the motor generators 16 and 18 are controlled.

  The torque conversion travel mode and the charge / discharge travel mode described above are modes in which the engine 20 and the motor generators 16 and 18 are controlled so that the required power is output to the drive shaft with the load operation of the engine 20. Hereinafter, both are collectively referred to as “hybrid driving mode”.

  In the engine direct torque traveling mode, the operation of the motor generator 18 is stopped, and the traveling is performed only by the torque directly transmitted from the engine 20 to the drive shaft through the power distribution mechanism 22 while taking the reaction force of the engine torque by the motor generator 16. Done.

  The EV travel mode is also called an electric travel mode or a motor travel mode. In this EV travel mode, the operation of the motor generator 18 is controlled so that the operation of the engine 20 is stopped and the power corresponding to the required power from the vehicle is output to the drive shaft. That is, the vehicle is driven only by the motor generator 18. Electric power to the motor generator 18 is supplied from the main battery 10.

<Cooling fan drive control>
The rotation speed of the motor 44 of the cooling fan 40 is adjusted by duty control. When the motor 44 is a direct current motor, the duty control periodically turns on and off the direct current voltage applied to the motor 44 as shown in FIG. 2, and the on / off cycle (P = on time + off time). This is a control method for changing the duty, which is the ratio of the on-time to. The duty is expressed by the following formula 1.

  When the duty is zero, no voltage is applied to the motor 44, so the cooling fan 40 is not driven. When the duty is 100% (MAX duty), the voltage of the low-voltage bus bars 34 and 35 is applied to the motor 44 as it is. When the duty is between zero and 100%, a voltage obtained by multiplying the voltage of the low-voltage bus bars 34 and 35 by the duty is an average voltage applied to the motor 44.

  As shown in FIG. 3, since there is a certain correlation between the rotation speed of the motor 44 and the duty, the rotation speed of the motor 44, that is, the rotation speed of the cooling fan 40 is adjusted by adjusting the duty by duty control. It can be adjusted to a desired rotational speed.

  Further, since there is a certain correlation between the rotation speed of the cooling fan 40 and the air volume, the air volume of the cooling fan 40 can be adjusted to a desired air volume by adjusting the duty.

  The control unit 45 of the cooling fan 40 includes a switching element for turning on / off the direct current inside, and turns on / off the direct current supplied to the motor 44 in accordance with the command duty D input from the control unit 70.

  In the present embodiment, the cooling fan 40 is driven by variable duty control or constant duty control. In the case of variable duty control, the control unit 70 determines the command duty D of the cooling fan 40 according to various detection parameters including at least the battery temperature TB, and outputs the command duty D to the control unit 45. Detection parameters referred to when determining the command duty D include the battery temperature TB, the intake air temperature of the cooling fan 40 detected by the temperature sensor 66, the battery temperature TB detected by the temperature sensor 61, and the vehicle speed sensor 65. The vehicle speed Vel, the battery current IV, the driving state of the engine 20 and the air conditioner, and the like may be included.

  In this embodiment, a duty map stored in the memory 72 of the control unit 70 is used to determine the command duty D. The duty map is a map showing the correlation between the values of various detection parameters and the command duty. As the duty map, various forms are conceivable. As an example, there is a map as shown in FIG.

  A solid line s1 shown in FIG. 4 is a reference line that defines a command duty D having a relatively low sensitivity to the battery temperature TB. The reference line s1 of the relatively low command duty D is, for example, when the outside air temperature is near room temperature and the temperature difference ΔT between the battery temperature TB and the intake air temperature of the cooling fan 40 is large (when relatively cool air is supplied). It is also used when priority is given to reducing power consumption over cooling capacity.

  In this case, as shown by the solid line s1 in FIG. 4, the command duty D is zero when the battery temperature TB is up to the temperature T10, and the minimum value D1 (MIN) when the temperature of the main battery 10 is between the temperature T10 and the temperature T11. Set to The minimum value D1 is the minimum duty for stably controlling the rotation speed of the motor 44 by duty control, and is about 10%, for example.

  When the battery temperature TB exceeds the temperature T11, the command duty D increases as the battery temperature TB increases, and when the battery temperature TB reaches the temperature T12, the command duty D becomes the maximum value D3 (MAX, 100% duty). . T10, T11, and T12 can take various values depending on the characteristics of the main battery 10, the type of battery (nickel metal hydride battery or lithium ion battery), etc. As an example, T10 is about 36 ° C. and T11 Is about 38 ° C., and T12 is about 47 ° C.

  The command duty D is determined by reflecting detection parameters such as the vehicle speed Vel of the hybrid vehicle 90 in addition to the battery temperature TB. For example, when the vehicle speed Vel of the hybrid vehicle 90 is high, the required power is large and the input / output power of the main battery 10 is large, so the command duty D is increased from the solid line s1 in FIG. 4 to the broken line s2. Conversely, when the vehicle speed Vel of the hybrid vehicle 90 is low, the required power is small and the input / output power of the main battery 10 does not increase so much, so the command duty D is reduced from the solid line s1 to the broken line s3 in FIG.

  Thus, the command duty D changes in the cross-hatched region A between the broken lines s2 and s3 in FIG. 4 according to the detection parameters such as the vehicle speed Vel of the hybrid vehicle 90 even when the battery temperature TB is constant. Hereinafter, the duty map defined by the solid line s1 and the broken lines s2 and s3 is referred to as a “low duty map”.

  A solid line u1 shown in FIG. 4 is a reference line that defines a command duty D having a relatively high sensitivity to the battery temperature TB. The reference line u1 of the relatively high command duty D is, for example, when the outside air temperature is near room temperature and the temperature difference ΔT between the battery temperature TB and the intake air temperature of the cooling fan 40 is small, or when the main battery 10 is rapidly cooled. Adopted when necessary.

  In this case, as indicated by the reference line u1, the command duty D is set to zero when the battery temperature TB is up to the temperature T10, and is set to D2 when the temperature of the main battery 10 is from the temperature T10 to the temperature T21 (lower than T11). Is done. D2 is a value higher than the minimum value D1 and smaller than the maximum value D3.

  When the battery temperature TB exceeds the temperature T21, the command duty D increases as the battery temperature TB increases, and when the battery temperature TB reaches the temperature T22, the command duty D becomes the maximum value D3 (MAX, 100% duty). Become. At this time, the increase rate of the command duty with respect to the battery temperature TB is larger than that in the case of the solid line s1 described above.

  Further, the command duty D changes in the cross-hatched region B between the broken lines u2 and u3 in FIG. 4 depending on the vehicle speed Vel of the hybrid vehicle 90 or the like. T21 and T22 can take various values like T10, T11, and T12. For example, T21 may be about 37 ° C. and T22 may be about 42 ° C. Hereinafter, the duty map defined by the solid line u1 and the broken lines u2 and u3 is referred to as a “high duty map”.

  When performing variable duty control, the control unit 70 determines the command duty D of the cooling fan 40 based on the duty map as described, and outputs the command duty D to the control unit 45. In determining the command duty D, which of the low duty map and the high duty map is referred to depends on the battery temperature TB, the temperature difference ΔT between the battery temperature TB and the intake air temperature of the cooling fan 40, the vehicle driving condition ( It is determined according to engine driving conditions and air conditioner driving conditions.

  In FIG. 4, only two types of duty maps (a high duty map and a low duty map) are shown, but a larger number of duty maps may be stored. Further, in the present embodiment, the command duty D is determined based on the map, but the command duty D may be calculated based on a function using a detection parameter such as the battery temperature TB as a variable.

  Further, as described above, in this embodiment, constant duty control is also performed. In the case of constant duty control, the control unit 70 outputs a constant command duty D to the control unit 45 for a fixed period. The command duty D used in the constant duty control may be constant for a certain period, and may be a different value for each constant duty control.

  The command duty D when performing constant duty control depends on the battery temperature TB, the input / output power Win, Wout, the vehicle speed Vel, the accelerator opening Acc, the gradient Inc, the engine drive status, etc., as will be described in detail later. It is determined. In this embodiment, the cooling fan 40 is driven by this constant duty control, and the presence / absence of abnormality of the cooling fan 40 is determined based on the difference Δω between the actual rotational speed and the target rotational speed obtained at that time.

<Basic operation of in-vehicle secondary battery cooling system>
Next, the operation of the cooling system 80 for the in-vehicle secondary battery will be described with reference to FIGS. When the Ready-ON signal (vehicle start signal) is input, the control unit 70 detects the battery temperature TB by the temperature sensor 61 and compares it with the first temperature T0 as shown in Step S101 of FIG. Here, the first temperature T0 is a temperature defined according to the heat resistance, heat generation characteristics, and the like of the main battery 10, and is the lowest temperature at which forced air cooling of the main battery 10 is necessary. For example, 36 ° C. is set as the first temperature T0.

  When the battery temperature TB is lower than the first temperature T0, the control unit 70 stands by until the battery temperature TB reaches the first temperature T0. Specifically, the battery temperature TB is detected by the temperature sensor 61 at a predetermined timing (S102), and the detected temperature is compared with the first temperature T0 (S103).

  When the cooling fan 40 is driven with a constant duty control for abnormality detection processing in a state where the battery temperature TB is low (that is, a state where cooling by the cooling fan 40 is unnecessary), the main battery 10 is overcooled, and the main battery 10 There is a possibility that the charging / discharging characteristics of the battery may be deteriorated and unnecessary power consumption may be caused. Therefore, a control flow is constructed using steps S101, S102, and S103 so that the cooling fan 40 is not operated when the battery temperature TB is low.

  When the battery temperature TB is equal to or higher than the first temperature T0, the control unit 70 proceeds to step S104 and compares the battery temperature TB with the second temperature T1. Here, the second temperature T1 is higher than the first temperature T0, for example, a temperature of about 40 ° C.

  This step is a step of determining whether or not the battery temperature TB is in a high temperature state. In other words, whether or not the drive control of the cooling fan 40 is constant duty control does not lead to overheating of the main battery 10. This is a determination step. In this step, if the determination is Yes, that is, if it is determined that T0 ≦ TB <T1, it is determined that the main battery 10 is not in a high temperature state. On the other hand, when it is determined No in this step, that is, when T1 ≦ TB is determined, the main battery 10 is determined to be in a high temperature state, and execution of the constant duty control is temporarily prohibited.

  If Yes in step S104, that is, if T0 ≦ TB <T1, the control unit 70 proceeds to step S105 and confirms whether or not EV traveling is in progress. Moreover, also when battery temperature TB reaches 1st temperature T0 by step S103, the control part 70 progresses to step S105.

  As described above, the EV traveling is a traveling state in which the operation of the engine 20 is stopped and power corresponding to the required power from the vehicle is output from the motor generator 18. Electric power to the motor generator 18 is supplied exclusively from the main battery 10.

  Here, since the current IB of the main battery 10 fluctuates with respect to fluctuations in the required driving force during EV travel, fluctuations in the battery temperature TB tend to occur. Therefore, from the viewpoint of preventing overheating of the main battery 10, in order to temporarily prohibit execution of constant duty control during EV traveling, a determination is made as to the driving state of the vehicle in step S105.

  If NO in step S105, that is, if T0 ≦ TB <T1 and the vehicle is not traveling in EV (stopping or hybrid traveling), the control unit 70 proceeds to step S106 and executes constant duty control.

  The constant duty control in step S106 requires a constant duty based on battery temperature, input / output power, etc., as will be described in detail later. When the duty during the constant control is obtained, the cooling fan 40 is driven at the duty for a certain period. Further, the process proceeds to step S107, and an abnormality detection process for determining whether or not there is an abnormality in the cooling fan 40 based on the actual number of revolutions during the constant control is executed.

  As described above, the case where the vehicle is not traveling in EV includes stopping and hybrid traveling. During hybrid travel, it is possible to respond to changes in the required driving force by changing the output of the engine 20, so that the possibility that the current IB of the main battery 10 will fluctuate is low, and therefore the possibility that the battery temperature TB will fluctuate. Low. Further, when the vehicle is stopped, since there is no required driving force itself, the current IB of the main battery 10 is unlikely to fluctuate and the battery temperature TB is unlikely to fluctuate.

  Therefore, even if the fan drive is performed with constant duty control when the EV is not traveling, there is a low possibility that the main battery 10 will be insufficiently cooled. In addition, it is confirmed that the battery temperature satisfies T0 ≦ TB <T1, which is a condition for proceeding to step S106, and the main battery 10 is not in a high temperature state.

  That is, it can be estimated that the main battery 10 is not in a high temperature state and the battery temperature does not increase rapidly at the stage of proceeding to step S106. Therefore, even if the constant duty control having a lower cooling capacity than the variable duty control and the abnormality detection process based on the constant duty control are performed, the rapid deterioration (deterioration due to overheating) of the main battery 10 can be avoided.

  When the abnormality detection process is executed, the control unit 70 drives the cooling fan 40 by variable duty control based on the duty map of FIG. 4 until Ready-OFF is reached (until the control unit 70 is shut down) (S108). ).

  Going back to the flowchart, when No in step S104, that is, when T1 ≦ TB, and when Yes in step S105, that is, when the vehicle traveling state is EV traveling, control is performed. The unit 70 proceeds to step S109.

  In step S109, the cooling fan 40 is driven by variable duty control based on the duty map of FIG. 4 to prevent overheating of the main battery 10 during EV traveling or when the battery temperature TB is equal to or higher than T1.

  Here, when the process proceeds from Ready-On to step S109, the condition for executing constant duty control (first constant control) has never been satisfied, and only variable control is executed. In this embodiment, in order to obtain an opportunity for abnormality detection processing in such a case, in the next step S110, on the basis of the operating state of the variable control being executed, an exceptionally constant duty control (second constant control) (Control) is executed.

  Specifically, in step S110, control unit 70 determines whether or not a change in command duty (drive command value) is equal to or greater than a predetermined amount Th. For example, it is determined whether or not the difference between the minimum value (minimum value) and the maximum value (maximum value) of the latest command duty is greater than or equal to a predetermined amount Th.

A large change in command duty means that the command duty goes back and forth between large and small, and it is considered that substantially the same cooling effect can be obtained if it is fixed at the command duty in the average region. It is done. Therefore, when the variation of the command duty in the variable duty control is equal to or greater than the predetermined value Th, the control unit 70 switches from the variable duty control to the constant duty control (second constant control). In this constant duty control, the duty D _AVE in the average area of the command duty that varies in the variable duty control is fixed as the command duty.

The average area duty D _AVE may be an average value of the minimum value (minimum value) D _LMIN of the latest command duty and the maximum value (maximum value) D _LMAX of the command duty. Alternatively, it may be an average value of a plurality of command duties sampled in a predetermined sampling period. Alternatively, the average value may be a value obtained by adding a predetermined margin.

In addition, the control unit 70 proceeds to step S107, and performs abnormality determination detection processing during the second constant control. Specifically, the control unit 70 compares a constant command rotational speed (ideal rotational speed) based on the command duty D _AVE with the actual rotational speed, and the difference Δω or the absolute value of the difference Δω is greater than or equal to a predetermined threshold value. If it is, it is determined that an abnormality has occurred in the cooling fan 40, and a fan abnormality signal is output and stored, for example, in the failure diagnosis function unit of the control unit 70 (diag output).

  On the other hand, when the rotational speed difference Δω or the absolute value of the difference Δω is less than a predetermined threshold, the control unit 70 determines that the cooling fan 40 is normal and outputs a fan normal signal, for example, as a diagnosis. Here, the fixed period is a period in which the difference between the actual rotational speed of the cooling fan 40 and the target rotational speed based on the command duty can be determined, and is, for example, a time of about several tens of seconds to several minutes.

  After determining whether there is an abnormality, the control unit 70 drives the cooling fan 40 by variable duty control based on the duty map of FIG. 4 until Ready-OFF is set (S108).

  When the fluctuation amount of the command duty is less than the predetermined value Th in step S110, the control unit 70 returns the control flow to step S101, and again confirms the battery temperature TB (S101, S103, S104) and the traveling state. Confirmation (S105) is performed. And until it progresses to step S107 which finally performs abnormality detection processing of the cooling fan 40, the cooling fan 40 is drive-controlled based on variable duty control (S109).

  As described above, in the control flow of the cooling system according to the present embodiment, an exception is recognized in the condition in which execution of constant duty control is temporarily prohibited, and a constant duty is set with a setting different from the setting when it is prohibited. Control is in progress. By doing in this way, compared with the case where an exception is not recognized, the execution rate of fixed duty control becomes high, Therefore, the execution rate of an abnormality detection process also increases. By increasing the chance of abnormality detection processing, it becomes possible to detect abnormality of the cooling fan 40 at an early stage.

  In general, a period from when the vehicle is started (Ready-ON) to when the driving is stopped after the vehicle travels a certain distance (Ready-OFF) is referred to as “trip”. In order to detect an abnormality in the cooling fan 40 at an early stage, the ratio of trips that perform abnormality detection processing (hereinafter referred to as “inspected trips”) is set to a certain value (eg, 60% or more), and abnormality detection processing is performed once It is desired to make the ratio of trips that have not occurred (hereinafter referred to as “uninspected trips”) less than a certain value (for example, less than 40%). According to the present embodiment, since the execution rate of the abnormality detection process increases, the rate of inspected trips can be set to a high level as requested.

<Constant duty control>
Next, the constant duty control of the cooling fan 40 in step S106 of FIG. 5 will be described in detail with reference to FIG. The constant duty control of the cooling fan 40 is a process including a step of rotating the cooling fan 40 at a constant command duty D for a predetermined period (first constant duty control).

  The command duty D when performing this constant duty control is changed according to the battery temperature TB, the input / output power Win, Wout, and the like. Specifically, as shown in step S201 of FIG. 6, when performing constant duty control, the controller 70 first exceeds the first temperature T0 only after the battery temperature TB rises from below the first temperature T0. Judge whether or not.

  When determining that the condition of step S201 is satisfied, the control unit 70 jumps from step S201 to step S211 and holds the command duty D at the minimum value D1 in the duty map shown in FIG. 4 for a certain period. . Thereby, the cooling fan 40 is controlled to rotate at a constant target rotation speed (minimum rotation speed).

  In step S107 in FIG. 5, the control unit 70 detects the actual rotational speed of the motor 44, that is, the actual rotational speed of the cooling fan 40 by the rotational speed sensor 64. Then, the control unit 70 compares a constant command rotational speed (ideal rotational speed) based on the command duty D with the actual rotational speed, and when the difference Δω or the absolute value of the difference Δω is equal to or greater than a predetermined threshold value. Determines that an abnormality has occurred in the cooling fan 40 and outputs a fan abnormality signal to, for example, the failure diagnosis function unit of the control unit 70 for storage (diag output).

  On the other hand, when the rotational speed difference Δω or the absolute value of the difference Δω is less than a predetermined threshold, the control unit 70 determines that the cooling fan 40 is normal and outputs a fan normal signal, for example, as a diagnosis. Here, the fixed period is a period in which the difference between the actual rotational speed of the cooling fan 40 and the target rotational speed based on the command duty can be determined, and is, for example, a time of about several tens of seconds to several minutes.

  If the control unit 70 determines NO in step S201, the control unit 70 proceeds to step S202 and determines whether or not the following condition is satisfied. That is, the control unit 70 calculates the input power Win to the main battery 10 from the voltage of the main battery 10 detected by the voltage sensor 62 shown in FIG. 1 and the current of the main battery 10 detected by the current sensor 63.

  Then, when the input power Win (charging power) to the main battery 10 is smaller than the predetermined threshold value Win_Lo, the control unit 70 does not increase the temperature of the main battery 10, so even if the air volume of the cooling fan 40 is small. If it is determined to be good, the process jumps to step S211, and constant duty control is performed to set the command duty D to the minimum value D1. Further, the process proceeds to step S107 in FIG. 5 to detect whether the cooling fan 40 is abnormal. When the input power Win to the main battery 10 is equal to or greater than the predetermined threshold value Win_Lo, the control unit 70 proceeds to step S203 and determines whether or not the following condition is satisfied.

  When determining NO in step S202, the control unit 70 proceeds to step S203, and determines whether or not the output power Wout is less than a predetermined threshold value Wout_Lo. That is, the control unit 70 calculates the output power Wout output from the main battery 10 from the voltage of the main battery 10 detected by the voltage sensor 62 and the current of the main battery 10 detected by the current sensor 63, and the output power Wout A predetermined threshold value Wout_Lo is compared.

  When the output power Wout from the main battery 10 is smaller than the predetermined threshold value Wout_Lo, the temperature rise of the main battery 10 is also small, so the control unit 70 determines that the air volume of the cooling fan 40 may be small and proceeds to step S211. Jump to set the command duty D to the minimum value D1. Further, the process proceeds to step 107 in FIG. 5 to detect whether the cooling fan 40 is abnormal.

  On the other hand, when output power Wout to main battery 10 is equal to or greater than a predetermined threshold value Wout_Lo, control unit 70 proceeds to step S204 and determines whether or not the following condition is satisfied.

  In step S204, the control unit 70 compares the vehicle speed Vel with a predetermined threshold value Vel_Lo. When the vehicle speed Vel is smaller than the predetermined threshold Vel_Lo, the temperature rise of the main battery 10 is also small, so the control unit 70 determines that the air volume of the cooling fan 40 may be small and jumps to step S211 to The duty D is set to the minimum value D1. Further, the process proceeds to step 107 in FIG. 5 to detect whether the cooling fan 40 is abnormal. When the vehicle speed Vel is equal to or higher than the predetermined threshold value Vel_Lo, the control unit 70 proceeds to step S205 and determines whether or not the following condition is satisfied.

  In step S205, the control unit 70 compares the accelerator opening Acc with a predetermined threshold Acc_Lo. When accelerator opening Acc is smaller than predetermined threshold value Acc_Lo, that is, when the required driving force of hybrid vehicle 90 is small, the temperature rise of main battery 10 is also small. It is determined that the number may be small, the process jumps to step S211, and the command duty D is set to the minimum value D1. Further, the process proceeds to step S107 in FIG. 5 to detect whether the cooling fan 40 is abnormal.

  On the other hand, when the accelerator opening Acc is equal to or larger than the predetermined threshold Acc_Lo, the control unit 70 proceeds to step S206 and determines whether or not the following condition is satisfied.

  In step S206, the control unit 70 checks whether or not the on / off state signal of the engine 20 input from another control device is an on signal. When the on / off state signal of the engine 20 is an on signal, that is, when the engine 20 is driven, the control unit 70 sets the command duty D to the minimum value D1. Further, the process proceeds to step S107 in FIG. 5 to detect whether the cooling fan 40 is abnormal.

  When the engine 20 is turned on, even if the required power of the hybrid vehicle 90 is increased, the required power is output from the engine 20, so that the output power of the main battery 10 does not increase so much. Therefore, the temperature rise of the main battery 10 is small, and the air volume of the cooling fan 40 may be small. Therefore, when determining that the engine 20 is turned on in step S206, the control unit 70 jumps to step S211 and sets the command duty D to the minimum value D1. Further, the process proceeds to step S107 in FIG. 5 to detect whether the cooling fan 40 is abnormal.

  On the other hand, when the on / off state signal of the engine 20 input from another control device is the engine 20 off signal, the control unit 70 proceeds to step S207 and determines whether or not the next specific condition is satisfied. To do.

  In step S207, the control unit 70 compares the gradient Inc with a predetermined threshold Inc_Lo. That is, the control unit 70 acquires data on the gradient Inc in the travel route of the hybrid vehicle 90 from the navigation system 30 on which the hybrid vehicle 90 is mounted. If the current gradient Inc is smaller than the predetermined threshold Inc_Lo, it is determined that there is little possibility of an increase in required output due to a steep uphill and a regenerative power increase due to a steep downhill, and jumps to step S211. The command duty D is set to the minimum value D1. Further, the process proceeds to step S107 in FIG. 5 to detect whether the cooling fan 40 is abnormal.

  On the other hand, when the gradient Inc in the travel route is larger than the predetermined threshold Inc_Lo, the control unit 70 determines that there is a possibility of an increase in required output due to a steep uphill or a increase in regenerative power due to a steep downhill. The process proceeds to the next step S208.

  As described above, the controller 70 determines whether (1) the battery temperature TB has exceeded T0 for the first time after rising from below the first temperature T0 in steps S201 to S207 shown in FIG. It is determined whether or not a specific condition is satisfied whether the input / output power is small, (3) the vehicle speed Vel, the accelerator opening Acc, the gradient in the travel route is small, or (4) the engine 20 is on. If any one of the specific conditions is satisfied, the process jumps to step S211 to hold the command duty D at the minimum value D1 for a certain period. Furthermore, it progresses to step S107 of FIG. 5, and the presence or absence of abnormality of the cooling fan 40 is determined. Accordingly, it is possible to suppress power consumption caused by driving the cooling fan 40 without overcooling the main battery 10.

  When determining that none of the specific conditions is satisfied in steps S201 to S207, the control unit 70 proceeds to step S208 and determines whether or not the battery temperature TB is higher than the reference temperature T3. The reference temperature T3 is a temperature that is equal to or higher than the first temperature T0 and lower than the second temperature T1 that prohibits the abnormality detection processing of the cooling fan 40. As described above, the second temperature T1 is variable depending on the frequency of abnormality detection processing of the cooling fan 40, but may be 40 ° C. as an example. As in the example described above, when T0 is set to 36 ° C., the reference temperature T3 is a temperature not lower than 36 ° C. and lower than 40 ° C., and can be set to 38 ° C., for example.

  For example, when the battery temperature TB exceeds the reference temperature T3, the controller 70 determines that the battery temperature TB is equal to or higher than the first temperature T0 (36 ° C.) and lower than the second temperature T1 (40 ° C.) and the reference temperature T3. In the case of 39 ° C., which exceeds (38 ° C.), the control unit 70 proceeds to step S209.

  In step S209, the control unit 70 keeps the command duty D constant at the maximum value D3 shown in the duty map of FIG. Thereby, the cooling fan 40 is controlled to rotate at a constant target rotational speed (maximum rotational speed).

  Then, similarly to the above description, the control unit 70 proceeds to step S107 in FIG. 5, detects the actual rotational speed of the motor 44 by the rotational speed sensor 64 shown in FIG. The rotational speed (command rotational speed, ideal rotational speed) is compared with the actual rotational speed, and the presence or absence of abnormality is determined based on the difference Δω or the absolute value of the difference Δω.

  Thus, when the battery temperature TB is relatively high, there is no risk that the main battery 10 will be overcooled even if the cooling fan 40 is driven at the maximum rotational speed to cool the main battery 10, and conversely the main battery 10 is not cooled. Cooling of the battery 10 is required. Therefore, when the battery temperature TB is relatively high, the control unit 70 detects whether there is an abnormality in the cooling fan 40 while keeping the command duty D constant at the maximum value D3.

  In addition, when the battery temperature TB is equal to or lower than the reference temperature T3, the control unit 70, for example, has the battery temperature TB that is equal to or higher than the first temperature T0 (36 ° C.) and lower than the second temperature T1 (40 ° C.). In the case of 37 ° C. below T3 (38 ° C.), the process proceeds to step S210. In step S210, the control unit 70 keeps the command duty D constant as an intermediate value DM between the maximum value D3 and the minimum value D1 shown in the duty map of FIG.

  Thereby, the cooling fan 40 is controlled to rotate at a constant target rotational speed (intermediate rotational speed). As described above, the control unit 70 proceeds to step S107 in FIG. 5, detects the actual rotational speed of the motor 44 by the rotational speed sensor 64 shown in FIG. 1, and is a constant target rotational speed based on the command duty D. Whether or not there is an abnormality is determined according to the difference Δω between the actual rotational speed and the actual rotational speed, and a signal indicating the result is output as a diagnosis.

  Next, an example of the operation of the cooling system for the in-vehicle secondary battery along the control flow described above will be described with reference to FIGS. These figures show examples of the operation of the cooling system. In particular, the constant duty control (second constant control) in which the setting is changed as an exception under the condition that the constant duty control (first constant control) is once prohibited. An example of performing control and abnormality detection processing is shown.

  The upper part of FIG. 7 shows the battery temperature TB, and the lower part shows the command duty D. The upper part of FIG. 8 shows the battery temperature TB, the middle part shows the on / off state of EV travel, and the lower part shows the command duty D. In each graph, the horizontal axis indicates time.

<When the abnormality detection process is performed when the battery temperature TB at the start is equal to or higher than the second temperature>
The operation example shown in FIG. 7 is an operation example that proceeds in the order of S101 → S104 → S109 → S110 → S101 → S104 → S109 → S110 → S111 → S107 → S108 in the flow chart of FIG.

  First, a Ready-ON signal is input to the control unit 70 at time t0 in FIG. Immediately before time t0, the hybrid vehicle 90 and the cooling fan 40 are stopped at Ready-OFF, and the command duty D of the cooling fan 40 is zero. Further, immediately before time t0, the battery temperature TB is a temperature Ta higher than the second temperature T1.

  When Ready-ON is reached at time t0, control unit 70 first compares battery temperature TB with first temperature T0 (S101 in FIG. 5). In the example of FIG. 7, at the time t0, the battery temperature TB (Ta) is equal to or higher than the first temperature T0.

  In response to this, the control unit 70 compares the battery temperature TB with the second temperature T1 (S104 in FIG. 5). In the example of FIG. 7, at the time t0, the battery temperature TB (Ta) is equal to or higher than the second temperature T1.

  Next, the control unit 70 performs variable duty control on the cooling fan 40 (S109 in FIG. 5), thereby cooling the main battery 10 in a high temperature state.

  Next, the control unit 70 determines whether or not the command duty variation in the variable duty control is equal to or greater than a predetermined value Th (S110 in FIG. 5). Since the command duty variation is less than the predetermined value Th at the stage of time t0, the control step returns to S101. Thereafter, the flow of steps S104 → S109 → S110 → S101 loops until time t1.

At time t1, the amount of change in the command duty becomes equal to or greater than a predetermined value Th. At this time, the control unit 70 executes constant duty control with D _AVE that is an average value of the maximum value (maximum value) D _LMAX and the minimum value (minimum value) D _LMIN of the command duty as a fixed command value (S111 in FIG. 5). ). Further, at this time, the control unit 70 executes an abnormality detection process for determining whether or not the cooling fan 40 is abnormal (S107 in FIG. 5).

  If a certain period of time elapses after the cooling fan 40 starts to be driven with constant duty control, the control unit 70 ends the constant duty control of the cooling fan 40 and shifts to variable duty control at time t2 (S108 in FIG. 5). ). That is, the control unit 70 determines a command duty D that varies according to the battery temperature TB and the like based on the duty map of FIG. 4, and drives the cooling fan 40 with the varying command duty D.

<When the abnormality detection process is performed when the vehicle is traveling in EV>
The operation example shown in FIG. 8 is an operation example that proceeds in the order of S101 → S102 → S103 → S105 → S109 → S110 → S101 → S104 → S105 → S109 → S110 → S111 → S107 → S108 in the flow chart of FIG.

  First, a Ready-ON signal is input to the control unit 70 at time t0 in FIG. Immediately before time t0, the hybrid vehicle 90 and the cooling fan 40 are stopped at Ready-OFF, and the command duty D of the cooling fan 40 is zero. Further, immediately before time t0, the battery temperature TB is a temperature Ta lower than the first temperature T0.

  When Ready-ON is reached at time t0, control unit 70 first compares battery temperature TB with first temperature T0 (S101 in FIG. 5). In the example of FIG. 8, at the time t0, the battery temperature TB (Ta) is lower than the first temperature T0.

  At this time, the control unit 70 waits until the battery temperature TB reaches the first temperature T0 (until time t2) without driving the cooling fan 40 (S102 and S103 in FIG. 5). In the example shown in FIG. 8, the vehicle starts EV traveling at time t1 during this standby period. In the example shown in FIG. 8, EV travel is continuously executed thereafter.

  When the battery temperature TB reaches the first temperature T0 at time t2, the control unit 70 determines whether or not the hybrid vehicle 90 is traveling in EV (S105 in FIG. 5). Since EV traveling is being executed at time t2, the control unit 70 drives and controls the cooling fan 40 by variable duty control (S109 in FIG. 5). Thereby, the main battery 10 is cooled.

  Furthermore, the control unit 70 determines whether or not the change in the command duty of the cooling fan 40 is equal to or greater than a predetermined value Th (S110). At time t2, since the variation of the command duty of the cooling fan 40 is less than the predetermined value Th, the control step returns to S101. Thereafter, the flow of steps S104 → S105 → S109 → S110 → S101 loops until time t1.

At time t3, the amount of change in the command duty becomes equal to or greater than a predetermined value Th. At this time, the control unit 70 executes constant duty control with D _AVE that is an average value of the maximum value (maximum value) D _LMAX and the minimum value (minimum value) D _LMIN of the command duty as a fixed command value (S111 in FIG. 5). ). Further, the control unit 70 executes an abnormality detection process for determining whether or not the cooling fan 40 is abnormal (S107 in FIG. 5).

  If a certain period of time elapses after the cooling fan 40 starts to be driven with constant duty control, the control unit 70 ends the constant duty control of the cooling fan 40 and shifts to variable duty control at time t4 (S108 in FIG. 5). ). That is, the control unit 70 determines a command duty D that varies according to the battery temperature TB and the like based on the duty map of FIG. 4, and drives the cooling fan 40 with the varying command duty D.

<Other Embodiments Regarding Command Duty Fluctuation Criteria>
In the embodiment described above, the command duty of the cooling fan 40 is directly used at the time of determining the command duty fluctuation, but this is not a limitation. For example, the change in the command duty may be indirectly determined by detecting that the vehicle operation in which the command duty fluctuates is performed.

  As a case where the command duty varies, a case where the load of the main battery 10 varies can be cited. Therefore, the change in the command duty may be estimated based on the tendency of the battery current IV of the main battery 10 to increase or decrease.

  Moreover, the fluctuation | variation of a vehicle speed is mentioned as another case where the load of the main battery 10 fluctuates. Therefore, the change in the command duty may be estimated based on the increasing or decreasing tendency of the vehicle speed or the accelerator opening degree Acc.

  In addition, the load on the main battery 10 also varies when switching between EV traveling and hybrid traveling. From this, the variation in the command duty may be estimated based on the ON / OFF operation of the engine 20.

  Further, the output of the vehicle also changes depending on the road gradient, and as a result, the load on the main battery 10 changes. From this, the variation of the command duty may be estimated according to the road surface gradient condition. Specifically, gradient information in the traveling direction is acquired from the navigation system 30, and fluctuations in the command duty are estimated based on the gradient information.

  Furthermore, the load of the main battery 10 also changes depending on the driving situation of the vehicle auxiliary equipment. For example, the load of the main battery 10 changes according to the output status of the air-conditioning blower having a relatively high power load among the auxiliary machines. Therefore, the load of the main battery 10 may be calculated according to the air volume setting of the air conditioner or the defroster, and the change in the command duty to the cooling fan 40 according to this may be estimated.

  When the ECO mode that is the power saving mode can be set for the hybrid vehicle 90, the output of the main battery 10 is reduced during the execution of the ECO mode. Therefore, the variation of the command duty may be estimated according to the ON / OFF operation of the setting switch in the ECO mode.

<Other embodiments>
In the embodiment described above, the abnormality detection process of the cooling fan 40 is performed only once per trip, but may be performed a plurality of times during one trip. For example, as shown in step S112 of FIG. 9, it is periodically checked whether or not the elapsed time after executing the abnormality detection process is equal to or greater than the reference time, and the elapsed time is equal to or greater than the reference time and Ready-OFF If not, the process may return to step S101 (S113). In this case, the number of abnormality detection processes during one trip is counted.

  In this case, the control unit 70 again monitors whether or not the condition for executing the abnormality detection process is satisfied, and when the condition is satisfied, the control unit 70 executes the abnormality detection process again. As described above, by performing the abnormality detection process periodically, the abnormality of the cooling fan 40 can be detected earlier.

  In the above-described embodiment, the control unit 70 calculates and outputs the command duty D. However, the control unit 45 of the cooling fan 40 calculates the command duty D and controls the motor 44. Also good.

  That is, the control unit 70 outputs information necessary for driving control of the cooling fan 40 such as the battery temperature TB to the control unit 45, and the control unit 45 drives the cooling fan 40 based on the information. The duty may be calculated.

  In the present embodiment, a DC motor is exemplified as the motor 44 that drives the cooling fan 40, but an AC motor may be used instead. In this case, the control unit 45 may generate an AC drive waveform corresponding to the duty to control the rotational speed of the AC motor.

  In addition, in the present embodiment, the cooling fan 40 is exemplified as a so-called suction type provided on the suction duct 46 side, but is not limited to this form. For example, a so-called suction-type cooling fan 40 that is disposed on the exhaust duct 49 side and causes the main battery 10 to blow cooling air by generating a negative pressure in the connection duct 47 or the casing 48 may be used.

  In this embodiment, the period from Ready-ON to Ready-OFF is set as “trip”. However, only a period satisfying a specific condition in these periods may be counted as “trip”. For example, during the period from Ready-ON to Ready-OFF, the length of the period is 10 minutes or more, continuous idle for 30 seconds or more is executed during that period, and the vehicle runs for a while at 40 km / h or more during that period. Only a period that satisfies at least one of the predetermined conditions may be counted as a “trip”.

Further, in the present embodiment, when the battery temperature TB is lower than the first temperature T0, the driving of the cooling fan 40 is prohibited from the viewpoint of avoiding overcooling of the main battery 10, but an exception is provided for this. May be. That is, even when the battery temperature TB is lower than the first temperature T0, the battery temperature TB of the main battery 10 quickly rises when the hybrid vehicle 90 is running on EV. Thus, during EV traveling, after the cooling fan 40 is once driven by variable control, when the change in the command duty becomes a predetermined value Th or more, constant control of the cooling fan 40 by the duty D _AVE And an abnormality detection process may be performed.

  The present invention is not limited to the embodiments described above, but includes all changes and modifications that do not depart from the technical scope or essence of the present invention defined by the claims. .

  10 Main battery, 16, 18 Motor generator, 20 Engine, 40 Cooling fan, 41 Fan body, 42 Suction port, 43 Discharge port, 44 Motor, 45 Control unit, 61 Battery side temperature sensor, 64 Speed sensor, 66 Cooling fan Side temperature sensor, 70 control unit, 80 cooling system, 90 hybrid vehicle.

Further, the command duty D when performing the constant duty control is determined according to the battery temperature TB, the input / output power Wi, Wo, etc. , as will be described in detail later. In this embodiment, the cooling fan 40 is driven by this constant duty control, and the presence / absence of abnormality of the cooling fan 40 is determined based on the difference Δω between the actual rotational speed and the target rotational speed obtained at that time.

The command duty D when performing this constant duty control is changed according to the battery temperature TB, the input / output power Wi, Wo, and the like . Specifically, as shown in step S201 of FIG. 6, when performing constant duty control, the controller 70 first exceeds the first temperature T0 only after the battery temperature TB rises from below the first temperature T0. Judge whether or not.

If the control unit 70 determines that the condition of step S201 is satisfied, the control unit 70 jumps from step S201 to step S207 to hold the command duty D at the minimum value D1 in the duty map shown in FIG. 4 for a certain period. . Thereby, the cooling fan 40 is controlled to rotate at a constant target rotation speed (minimum rotation speed).

If the control unit 70 determines NO in step S201, the control unit 70 proceeds to step S202 and determines whether or not the following condition is satisfied. That is, the control unit 70 calculates the input power Wi to the main battery 10 from the voltage of the main battery 10 detected by the voltage sensor 62 shown in FIG. 1 and the current of the main battery 10 detected by the current sensor 63.

Then, the control unit 70, when the input power to the main battery 10 Wi (charging electric power) is smaller than a predetermined threshold value Wi _lo, YES is determined in the step S202 of FIG. 6, the process proceeds to step S203 in FIG. 6 .

If it is determined YES in step S202, the control unit 70 proceeds to step S203, the output power Wo determines whether less than a predetermined threshold value Wo _lo. That is, the control unit 70 calculates the output power Wo output from the main battery 10 from the voltage of the main battery 10 detected by the voltage sensor 62 and the current of the main battery 10 detected by the current sensor 63, and the output power Wo comparing with a predetermined threshold value Wo _lo.

If the output power Wo from the main battery 10 is smaller than a predetermined threshold value Wo _lo, the process proceeds to step S207. That is, in this case, since both the input power Wi and the output power Wo are small, the temperature rise of the main battery 10 is also small. Therefore, the control unit 70 determines that the air volume of the cooling fan 40 may be small and proceeds to step S207 . Jump to set the command duty D to the minimum value D1. Further, the process proceeds to step S107 in FIG. 5 to detect whether the cooling fan 40 is abnormal.

On the other hand, the control unit 70, when the input power Wi to the main battery 10 is not smaller than a predetermined threshold value Wi_Lo, or, if the output power Wo is greater than a predetermined threshold value Wo _lo, the process proceeds to step S204, the following condition Judge whether to meet.

As described above, the control unit 70 determines whether (1) the battery temperature TB has exceeded T0 for the first time after rising from below the first temperature T0 in steps S201 to S203 shown in FIG. or output power is low, to determine whether a particular condition is met that, if the any one of a specific condition is met, go to step S 207, a period of time, the command The duty D is held at the minimum value D1. Accordingly, it is possible to suppress power consumption caused by driving the cooling fan 40 without overcooling the main battery 10.

Control unit 70, when it is determined that neither satisfy one specific condition, the process proceeds to step S204, it is determined whether the battery temperature TB is higher than the reference temperature T3. The reference temperature T3 is a temperature that is equal to or higher than the first temperature T0 and lower than the second temperature T1 that prohibits the constant duty control of the cooling fan 40. As described above, the second temperature T1 is variable depending on the frequency of abnormality detection processing of the cooling fan 40, but may be 40 ° C. as an example. As in the example described above, when T0 is set to 36 ° C., the reference temperature T3 is a temperature not lower than 36 ° C. and lower than 40 ° C., and can be set to 38 ° C., for example.

For example, when the battery temperature TB exceeds the reference temperature T3, the controller 70 determines that the battery temperature TB is equal to or higher than the first temperature T0 (36 ° C.) and lower than the second temperature T1 (40 ° C.) and the reference temperature T3. In the case of 39 ° C. when (38 ° C.) is exceeded, the control unit 70 proceeds to step S205 .

In step S205 , the control unit 70 keeps the command duty D constant at the maximum value D3 shown in the duty map of FIG. Thereby, the cooling fan 40 is controlled to rotate at a constant target rotational speed (maximum rotational speed).

In addition, when the battery temperature TB is equal to or lower than the reference temperature T3, the control unit 70, for example, has the battery temperature TB that is equal to or higher than the first temperature T0 (36 ° C.) and lower than the second temperature T1 (40 ° C.). In the case of 37 ° C. below T3 (38 ° C.), the process proceeds to step S206 . In step S206 , the control unit 70 keeps the command duty D constant as an intermediate value DM between the maximum value D3 and the minimum value D1 shown in the duty map of FIG.

Claims (1)

A cooling system for cooling a secondary battery for driving a vehicle mounted on a hybrid vehicle,
A cooling fan for blowing cooling air to the secondary battery;
A temperature sensor for detecting a battery temperature which is a temperature of the secondary battery;
With
The cooling fan is driven and controlled by variable control in which a drive command value is changed according to the battery temperature, or by first constant control in which the drive command value is fixed to a first command value,
During the first constant control, an abnormality detection process is performed for detecting whether or not there is an abnormality in the cooling fan based on the actual rotational speed of the cooling fan.
In the cooling system,
When the predetermined condition for executing the first constant control is not satisfied from the time of starting the vehicle and only the variable control is executed, the fluctuation of the drive command value in the variable control exceeds a predetermined amount. Then, the variable control is switched to the second constant control in which the command value is fixed to the value in the average region of the fluctuating drive command value, and the abnormality detection process is executed during the second constant control. A cooling system for an in-vehicle secondary battery.

Images