JP6717025B2 - In-vehicle battery cooling system - Google Patents

Description

The present invention relates to a vehicle battery cooling system.

BACKGROUND ART Conventionally, for example, Patent Document 1 describes a configuration in which a battery is appropriately shut off by flowing an inrush current to melt a fuse when a water leak sensor detects that a battery system mounted in a vehicle is flooded. ing.

JP, 2013-110813, A

In the configuration of Patent Document 1 described above, it is necessary to mount the water immersion sensor on the vehicle in order to detect the water immersion, which results in an increase in the number of parts.

An object of the present invention is to provide a vehicle-mounted battery cooling system can detect that the incoming water immersion through the blower without increasing the number of parts.

Vehicle battery cooling system according to the present invention includes a battery that is onboard a blower for sending cooling air to the battery-a blower motor for rotating the blanking Roi, and a control unit for controlling the rotational speed of the probe Rowamota, control section If there is no change in the rotational speed command by Lube Rowamota, the increase of the driving voltage command value of the probe Rowamota is greater than increment predetermined blower water containing determination threshold value, and the actual rotational speed of the probe Rowamota predetermined when greater than the lock determination threshold rotational speed, and a determination section determines that water has penetrated immersed in Bed Roi.

In vehicle-mounted battery cooling system, the water may be entering immersion through a blower for sending cooling air to the battery. An in-vehicle battery cooling system according to the present invention, it is possible to detect that the water has penetrated immersed in a blower based on the drive voltage instruction value of the blower motor, the water-containing to the blower without increasing the number of parts It is possible to detect, and as a result, it is possible to minimize and protect the in-vehicle battery from entering water.

It is a figure which illustrates the composition of the vehicle-mounted battery cooling system which is one embodiment of the present invention, and the vehicle in which this is installed. It is a control block diagram which illustrates the control system of a blower. It is a graph which shows the torque of a blower motor, and the relationship of a voltage command. It is a flowchart which illustrates the water entry determination processing to a blower.

Embodiments according to the present invention will be described below in detail with reference to the accompanying drawings. In this description, specific shapes, materials, numerical values, directions, etc. are examples for facilitating the understanding of the present invention, and can be appropriately changed according to applications, purposes, specifications and the like. Further, when a plurality of embodiments and modifications are included in the following, it is assumed from the beginning that the characteristic portions are appropriately combined and used.

FIG. 1 illustrates the configuration of a vehicle-mounted battery cooling system according to the present embodiment and a vehicle equipped with the same. Note that, for simplification of the illustration, in FIG. 1, a configuration having a low relevance to the vehicle-mounted battery cooling system according to the present embodiment is appropriately omitted. Moreover, the alternate long and short dash line in FIG. 1 represents a signal line.

The vehicle shown in FIG. 1 is a hybrid vehicle that uses an internal combustion engine ENG and rotary electric machines MG1, MG2 as drive sources. However, the vehicle in which the vehicle-mounted battery cooling system according to the present embodiment is mounted is not limited to this. In short, any vehicle can be used as long as it has a rotating electric machine as a drive source and a large-capacity battery that supplies electric power to the rotating electric machine.

In the vehicle (hybrid vehicle) shown in FIG. 1, the DC power output from the main battery 10 is boosted by the buck-boost DC/DC converter 12. The boosted DC power is orthogonally converted by the inverter 14. The converted AC power is supplied to at least one of the rotary electric machines MG1 and MG2.

For example, in the EV traveling mode in which the vehicle is driven only by the driving force of the rotating electric machine without driving the internal combustion engine ENG, electric power is supplied from the main battery 10 to the rotating electric machine MG2, and the driving force obtained thereby is supplied to the power distribution mechanism. It is transmitted to wheels 18 via 16.

In the HV traveling mode in which the driving force is output from the internal combustion engine ENG in addition to the rotary electric machine MG2, part of the driving force of the internal combustion engine ENG is transmitted to the wheels 18 via the power distribution mechanism 16. The remaining driving force is transmitted to the rotary electric machine MG1 via the power distribution mechanism 16, whereby the rotary electric machine MG1 is driven to generate electric power. The generated electric power is supplied to the rotary electric machine MG2, and the driving force obtained thereby is transmitted to the wheels 18 via the power distribution mechanism 16.

Further, the vehicle shown in FIG. 1 is provided with a branch electric path that branches from an electric path connecting the main battery 10 and the step-up/down DC/DC converter 12 and is connected to the step-down DC/DC converter 20. The DC power stepped down by the step-down DC/DC converter 20 is orthogonally converted by the blower inverter 22. The converted AC power is supplied to the blower motor 24. The blower motor 24 rotationally drives the blower 26, and the cooling air is taken in with this.
<In-vehicle battery cooling system configuration>

The vehicle-mounted battery cooling system according to the present embodiment includes a main battery (vehicle-mounted battery) 10, a blower 26, a blower motor 24, a blower inverter 22, and an ECU (electronic control unit) 30.

The main battery 10 is composed of a secondary battery such as a nickel hydrogen battery or a lithium ion battery. The main battery 10 is composed of, for example, a stack (laminated body) in which a plurality of battery cells (unit cells) of about 1 to 5 V are laminated. The main battery 10 is housed in the case 32. A supply port 34 and a discharge port 36 for cooling air are formed in the case 32. As described later, the cooling air sent from the blower 26 flows into the case 32 from the supply port 34, and the main battery 10 is air-cooled. The cooled air is discharged from the discharge port 36.

The blower 26 is a blower that sends cooling air to the main battery 10. The blower 26 is composed of, for example, a sirocco fan (multi-blade fan). The suction port 38 of the blower 26 in the present embodiment is directed to the interior of the vehicle. When the main battery 10 and the cooling system are installed in the lower part of the rear seat, the intake port 38 of the blower 26 is installed so as to face the vehicle interior via the cover that covers the lower part of the rear seat.

The blower 26 takes in the air in the vehicle compartment as cooling air. A filter 40 is attached to the intake port 38 in order to avoid inhalation of dust in the air and on the floor carpet during intake. For example, the filter 40 is composed of a mesh member having the same diameter as the suction port 38. The cooling air taken into the blower 26 via the filter 40 is sent to the main battery 10 via the duct 42. Here, when the user of the vehicle spills water around the suction port 38 while the blower 26 is operating, water may be sucked from the suction port 38 through the filter 40. In this case, water is assumed to be sent to the main battery 10 via the blower 26 together with the sucked air. In such a case, in order to prevent the water from entering immersed in the main battery 10 to quickly detect a water filled into the blower 26, in the present embodiment executes the water containing determination process to the blower to be described later.

The blower motor 24 drives the blower 26 to rotate. The blower motor 24 is composed of, for example, a three-phase brushless motor having a rated voltage of 14 [V]. A drive voltage (three-phase AC voltage) is applied to the blower motor 24 from the blower inverter 22, whereby the blower motor 24 is rotationally driven. The position of the rotor of the blower motor 24 is detected by the position sensor 44 and used for feedback control described later. In the following, for ease of understanding, it is assumed that the rotation speed [rpm] of the blower motor 24 and the rotation speed [rpm] of the blower 26 are the same.

The blower inverter 22 orthogonally converts the DC power supplied from the main battery 10 via the step-down DC/DC converter 20 or directly supplied from the sub-battery 28 and supplies the DC power to the blower motor 24. As shown in FIG. 2, the blower inverter 22 includes a plurality of switching elements, and on/off operations of these switching elements are controlled based on the PWM control signal sent from the control unit 48.

Referring again to FIG. 1, the ECU 30 controls various devices of the vehicle including the vehicle-mounted battery cooling system. The ECU 30 is composed of, for example, a computer, and includes a CPU 46 that is an arithmetic circuit and a memory 49 that is a storage device. The CPU 46 includes a control unit 48 that controls the blower 26, and a determination unit 50 that determines water entering the blower 26.

The memory 49 includes a volatile memory such as SRAM and a non-volatile memory such as ROM and hard disk. The memory 49 stores a program for executing a blower water entering determination process, which will be described later, a command voltage-motor torque map, and the like.

The ECU 30 receives detection values from various sensors mounted on the vehicle. Specifically, the voltage value Vb and the current value Ib of the main battery 10 are received from the voltage sensor 54 and the current sensor 56, respectively. Further, the ECU 30 receives the temperature Tb of the main battery 10 from the battery temperature sensor 58. Further, the ECU 30 receives the vehicle speed from the speed sensor 60, and receives the rotor positions of the rotary electric machines MG1, MG2 and the blower motor 24 from the MG1 rotation position sensor 62, the MG2 rotation position sensor 64, and the blower motor rotation position sensor 44, respectively. .. Further, the ECU 30 controls the volume level in the passenger compartment from the microphone 68, the on/off state of the audio system from the on/off switch 70 of the audio system, the opening degree of the vehicle window from the power window switch 72, and the on/off switch 74 of the air conditioning system. It is possible to receive the on/off state of the air conditioning from the.
<Blower control system>

FIG. 2 is a control block diagram illustrating the control system for the blower according to the present embodiment. In this embodiment, the command voltage V_com, which is the drive voltage command value for the blower motor 24, is converted into a PWM control signal, and the rotation speed [rpm] of the blower 26 is controlled by this.

PWM control is a type of voltage control, in which the ON voltage is kept constant and the average of the output voltage per cycle is changed by changing the ratio of the ON period per cycle, that is, the duty ratio [%]. Let The command voltage V_com to the blower motor 24 and the duty ratio have a correspondence relationship, and the higher the command voltage V_com, the higher the duty ratio. The higher the duty ratio, the higher the rotation speed of the blower motor 24 (so-called armature voltage control). As will be described later, the control unit 48 changes the duty ratio according to the change in the command voltage V_com, and thereby controls the rotation speeds of the blower motor 24 and the blower 26.

In the control block diagram illustrated in FIG. 2, the control unit 48 is virtually divided into a plurality of functional units. That is, the control unit 48 includes a rotation speed command generation unit 48A, a differential operation unit 48B, a PI control unit 48C, a two-phase→three-phase conversion unit 48D, and a PWM generation unit 48E.

A feedback loop is formed by the control unit 48, the blower inverter 22, the blower motor 24, and the blower motor rotational position sensor 44. The rotation speed control of the blower 26 will be described below along this loop. The temperature Tb of the main battery 10 and the vehicle compartment temperature are sent to the rotation speed command generation unit 48A of the control unit 48 from the host computer of the ECU 30. Based on these values, the rotation speed command generator 48A generates the command rotation speed R_com [rpm] of the blower motor 24 (and the blower 26). The actual rotation speed N_rev [rpm] of the blower motor 24 by the differential calculation unit 48B is subtracted from the command rotation speed R_com and sent to the PI control unit 48C.

In the PI control unit 48C, the command voltage V_com is generated based on the difference value (rotation difference value) between the command rotation speed R_com and the actual rotation speed N_rev. The correspondence relationship between the rotation difference value and the command voltage V_com is stored in the memory 49 in advance as map data, for example. Further, the PI control unit 48C converts the command voltage V_com into the d-axis component Vd* and the q-axis component Vq*. For example, in id=0 control used for general speed control, V_com=√(Vd* ² +Vq* ² ) (=(Vd* ² +Vq* ² ) ^1/2 ) and Vd*=0 Thus, the d-axis component Vd* and the q-axis component Vq* are obtained.

The 2-phase to 3-phase conversion unit 48D generates the 3-phase voltage signals Vu, Vv, Vw based on the d-axis component Vd* and the q-axis component Vq* of the command voltage and the rotor position θ of the blower motor 24. The PWM generator 48E generates a PWM control signal in which the duty ratios of the U-phase, V-phase, and W-phase are determined based on the three-phase voltage signals Vu, Vv, Vw. The PWM control signal is sent to each switching element of the blower inverter 22, and the on/off operation of these switching elements is controlled. The DC voltage stepped down from the main battery 10 via the step-down DC/DC converter 20 or directly applied from the sub-battery 28 becomes a three-phase square wave AC voltage by turning on/off the switching element of the blower inverter 22. Is transformed (orthogonal transformation).

By applying the three-phase voltage to the blower motor 24, the rotor of the blower motor 24 is rotationally driven. The rotation position θ (mechanical angle) of the rotor is detected by the blower motor rotation position sensor 44. The detected rotation position θ is differentiated by the differentiation calculation unit 48B to become the actual rotation speed N_rev (rotation speed), and the actual rotation speed N_rev is subtracted from the command rotation speed R_com. Hereinafter, the feedback control is executed so that the actual rotation speed N_rev matches the command rotation speed R_com.

In the control block shown in FIG. 2, variable control for changing the rotation speed command R_com and constant rotation speed control for keeping the rotation speed command R_com constant are possible. The variable control is control for performing air cooling by following the temperature Tb of the main battery 10, and the command rotation speed R_com changes according to the temperature Tb of the main battery 10, the vehicle compartment temperature, and the like. On the other hand, in the constant rotation speed control, the blower motor 24 is maintained at a predetermined rotation speed so that the rotation speed of the blower 26 becomes constant. The predetermined rotation speed may be, for example, a rotation speed of 2500 [rpm] or higher, and is set to 3000 [rpm], for example.

FIG. 3 is a graph showing the relationship between the motor torque of the blower motor 24 and the voltage command. In this graph, the horizontal axis represents the motor torque [mN] and the vertical axis represents the command voltage V_com. Although the unit of the command voltage V_com is shown by %, this indicates the duty ratio [%] of the PWM signal corresponding to the predetermined command voltage V_com, and the command voltage value is converted into the duty ratio. It is a thing.

In the graph of FIG. 3, the initial state of the blower motor 24 is indicated by a black circle 80. The initial state 80, at the time of shipment of the vehicle, that is, by a predetermined rotation of the blower 26 at a predetermined rotational speed in a state in which and the filter 40 not to enter the water immersion to the blower 26 is not clogged dust in new It means the rotation state of the blower motor 24 at that time. The motor torque and voltage command of the blower motor 24 in the initial state 80 are indicated by MT0 and V_com0, and these MT0 and V_com0 are actually measured before shipment of the vehicle and stored in the memory 49 in advance.

Further, in the graph of FIG. 3, the state of the blower motor 24 when the water has penetrated immersed in the blower 26 is shown by a black circle 82. At this time, since the blower 26 discharges water to the outside of the blower by the rotating blades, the motor torque MT1 is increased as compared with the initial state 80 (MT1>MT0). The voltage command V_com1 also increases compared to the initial state 80 (V_com1>V_com0). Blois water containing determination process described later, based on the increase in voltage command such blower motor 24 determines whether the water has penetrated immersed in the blower 26.

In the graph of FIG. 3, a black circle 84 indicates a state where the filter 40 is clogged with dust. In this state, the motor torque MT2 of the blower motor 24 is lower than that in the initial state 80 (MT2<MT0), and accordingly, the voltage command V_com2 of the blower motor 24 is also lower than that in the initial state 80 under constant rotation speed control. (V_com2<V_com0). This is because the flow of air to the blower 26 is stopped due to the clogging of the filter 40, and the blower 26 does not collect gas. This is because the amount of work is reduced without being able to get out. The phenomenon that the voltage command V_com of the blower motor 24 is lowered can be used to detect clogging of the filter 40 due to dust.

FIG. 4 is a flowchart exemplifying the water entry determination process for the blower in the present embodiment. This water entry determination process is executed by a program process by the determination unit 50 of the ECU 30. The determination unit 50 can read the water entry determination processing program from the memory 49 and execute the program at predetermined time intervals while the blower 26 (that is, the blower motor 24) is operating.

As shown in FIG. 4, the determination unit 50 first determines in step S10 whether the temperature Tb of the main battery 10 is higher than a predetermined blower drive start temperature T_K0. A value stored in advance in the memory 49 can be used as the predetermined blower drive start temperature T_K0. By this determination, it is possible to prevent the blower 26 from operating and the main battery 10 from being overcooled (too cool) even though the battery temperature Tb is low. If an affirmative determination (Yes) is made in step S10, the process proceeds to step S12, and if a negative determination (No) is performed, the process proceeds to step S20. In step S20, a water entry determination counter count(n) described later is reset to zero, and the process ends.

When an affirmative determination is made in step S10, the determination unit 50 determines whether or not there is a change in the rotation speed command in subsequent step S12. Specifically, for the blower motor 24, it is determined whether the current rotation speed command R_com(n) and the previous rotation speed command R_com(n-1) are substantially equal. When the rotation speed constant control of the blower motor 24 is executed in the water entry determination process, R_com(n)=R_com(n−1) is satisfied, and thus a positive determination (Yes) is made here. On the other hand, when the blower motor 24 is variably controlled, the rotation speed command is not changed unless, for example, the battery temperature Tb fluctuates. Therefore, a positive determination is made here. It should be noted that the determination based on “substantially equal” means that the determination is affirmative (Yes) as long as it can be regarded as substantially the same even if the determinations are not completely the same. As a result, it is possible to absorb the fluctuation of the rotation speed command R_com caused by the error in the detected values of the various sensors, the temporary fluctuation, and the like. If an affirmative decision is made in step S12, the operation proceeds to step S14, and if a negative decision is made, the counter is reset in step S20 and the processing ends.

When a positive determination is made in step S12, the determination unit 50 determines whether or not the voltage command of the blower motor 24 is larger than a predetermined value in subsequent step S14. Specifically, it is determined whether or not a difference (that is, an increment) obtained by subtracting the voltage command V_com0 in the initial state 80 from the current voltage command V_com is larger than a threshold value V_com_K for determining water entry into the blower 26. As the threshold value V_com_K, for example, a value acquired in an experiment in which the blower 26 is filled with water and stored in the memory 49 in advance can be used. If an affirmative determination (Yes) is made in step S14, the process proceeds to step S16, and if a negative determination (No) is made, the counter is reset in step S20 and the process ends. In the present embodiment, an example in which the increment of the voltage command of the blower motor 24 is compared with a predetermined threshold will be described, but the present invention is not limited to this, and the current voltage command V_com is compared with another threshold=(V_com0+V_com_K). May be.

When a positive determination is made in step S14, the determination unit 50 determines in subsequent step S16 whether the actual rotation speed N_rev of the blower motor 24 is larger than a predetermined lock determination threshold (predetermined rotation speed) N_lock_K. By this determination, it is possible to exclude the case where the voltage command V_com increases under the constant rotation speed control when a foreign matter other than water is caught in the blower 26 and enters the locked state. Here, the lock determination threshold value N_lock_K is set to a rotation speed (for example, 1000 [rpm]) smaller than the rotation speed range of the blower 26 in the normal operating state, and can be stored in the memory 49 in advance. If an affirmative determination (Yes) is made in step S16, the process proceeds to step S18. If a negative determination (No) is made, the counter is reset in step S20 and the process ends.

When an affirmative determination is made in step S16, the determination unit 50 increments the water entry determination counter count(n) (initial value=0) in subsequent step S18, and the counter count(n) is set to a predetermined value in subsequent step S22. It is determined whether or not it is larger than the count value count_K. The water entry determination counter count(n) has a function of measuring the time during which the state of being positively determined in each of steps S10 to S16 described above continues. By providing such a counter count(n), it is possible to further improve the accuracy of determining whether water has entered the blower 26.

When a negative determination (No) is made in step S22, the process returns to step S10 described above to continue the process. Then, each time a positive determination is made in steps S10 to S18, when the counter count(n) is incremented in step S18 and becomes larger than the predetermined count value count_K, a positive determination (Yes) is made in step S22, and the subsequent steps. In S24, it is determined that water has entered the blower 26, and the process ends. In this case, the control unit 48 stops the drive of the blower 26 by the blower motor 24, for example. As a result, it is possible to minimize water entering the main battery 10.

An in-vehicle battery cooling system of the present embodiment as described above, it is possible to detect that the water has penetrated immersed into the blower 26 based on voltage command V_com the blower motor 24 without increasing the number of parts Inundation can be detected quickly. As a result, water entry into the main battery 10 can be suppressed to a minimum, and the main battery 10 can be protected.

Further, in the present embodiment, when the actual rotation speed N_rev of the blower motor 24 is larger than the predetermined lock determination threshold N_lock_K, it is detected that water has entered the blower 26, so foreign matter other than water is caught and blower 26 is caught. It can be avoided that the case where the blower motor 24 is in the locked state is determined to be water entering, and the water entering the blower 26 can be accurately detected.

Further, in the present embodiment, when the state where the voltage command V_com of the blower motor 24 has increased due to the water entering the blower 26 continues for a predetermined time or longer, the occurrence of water entering the blower 26 is detected, so that it takes only a very short time. The temporary voltage command fluctuation is not judged as water entering, and the accuracy of water entering the blower is further improved.

It should be noted that the present invention is not limited to the configurations of the above-described embodiment and its modifications, and various modifications and improvements can be made within the matters described in the claims of the present application and the equivalents thereof. Needless to say.

10 main battery (vehicle battery), 22 blower inverter, 24 blower motor, 26 blower, 32 case, 34 supply port, 36 discharge port, 38 intake port, 40 filter, 42 duct, 48 control unit, 49 memory, 50 determination unit , MG1, MG2 Rotating electric machine.

Claims (1)

On-board battery,
A blower for sending cooling air to the battery,
A blower motor that rotationally drives the blower,
A control unit for controlling the rotation speed of the blower motor,
If there is no change in the rotational speed command of the blower motor by the control unit, the increase in the driving voltage command value of the blower motor is greater than a predetermined blower water containing determination threshold value increment, and the actual rotational speed of the blower motor is It is greater than a predetermined lock determination threshold rotation speed, and a determination section determines that water has penetrated immersed in the blower,
In-vehicle battery cooling system.

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