JP2006014453A - Cooling controller for two-power supply type battery loading vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a two-power supply type battery loading vehicle having a single fan type cooler which can suppress an increase in a size of a cooling fan and an increase in a power consumption while complicating a circuit configuration. <P>SOLUTION: The temperature of a vehicle loading high-voltage battery 11 and the temperature of a DC/DC converter 15 for a low pressure battery power supply are detected. A microcomputer 142 and the DC/DC converter 15 which perform the temperature management of the high voltage battery 11 are integrated. The cooling fan 13 for cooling commonly the high voltage battery 11 and the DC/DC converter 15 is controlled to be driven based on the detected temperatures. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a battery-equipped vehicle control device. The present invention is installed in a battery-equipped vehicle that includes a high-voltage battery, a low-voltage battery that is fed from the high-voltage battery, and a DC / DC converter that controls power transfer between these batteries. Examples of this type of battery-equipped vehicle include a hybrid vehicle, a fuel cell vehicle, and a battery vehicle.

  In the above-mentioned battery-equipped vehicle, a large-capacity battery (hereinafter also referred to as a high-voltage battery) for generating traveling power formed by connecting a number of cell batteries in series, and a motor for generating traveling power (hereinafter also referred to as a traveling motor) , Equipped with an inverter powered by a high voltage battery to drive and control the traveling motor, and a battery monitor circuit, which detects the voltage of each cell battery of the high voltage battery, the voltage of the high voltage battery, the current temperature, etc. The charging / discharging of the high-voltage battery is controlled based on the detection data to prevent the overcharge and overdischarge of each cell battery and the excessive increase in the temperature of each cell battery. In the battery-equipped vehicle, an electric cooling fan is usually provided for cooling the inverter and the high-voltage battery, and the inverter and the high-voltage battery are usually forcedly cooled by the cooling air formed by the fan.

As an example of the fan cooling method, the following Patent Document 1 discloses that when the ambient temperature exceeds a predetermined threshold value, the cooling air formed by the common cooling fan is supplied to the high pressure battery to cool it, and the high pressure battery We have proposed a single-fan type cooling system that cools the cooling air from the inverter. According to this single fan type cooling device, the high-voltage battery and the inverter can be cooled by a single cooling system, and effects such as downsizing of the cooling fan can be achieved.
Patent No. 3509517 Moreover, in the above battery-equipped vehicle, in addition to the high-voltage battery, inverter and battery monitor circuit for supplying the driving power to the driving motor, the low-voltage battery for supplying electric power to various in-vehicle small electric loads, and the storage of the high-voltage battery It is common to equip a step-down DC / DC converter (down converter) that steps down electric power and charges a low-voltage battery. Hereinafter, this battery-equipped vehicle is referred to as a dual-power-source battery-equipped vehicle. This DC / DC converter has a function of driving and controlling the DC / DC converter so as to at least monitor the state of charge of the low-voltage battery and maintain it at an appropriate charge level.

  When the cooling of the conventional high-voltage battery and the inverter for controlling the traction motor is shared by the cooling fan, since there is a strong correlation between the heat generation states as described above, no major problem arises. When a single fan type cooling device is shared for cooling a high-voltage battery and a step-down DC / DC converter of a vehicle equipped with a dual power supply battery, the temperature state of the DC / DC converter and the temperature state of the high-voltage battery greatly depend on the operating conditions. Since there are many differences, the above-described cooling fan drive control based on the ambient temperature described above is based on the maximum heat generation (temperature rise) of the DC / DC converter assumed from the ambient temperature and the maximum heat generation of the high-voltage battery ( As the cooling air volume of the cooling fan must be set on the assumption that both the temperature and the temperature rise), the cooling fan becomes large and expensive. A problem that costs an increase in power has occurred. For example, the temperature of the high-voltage battery has a positive correlation mainly with the drive level of the traveling motor, but the DC / DC converter depends on the low-voltage electric load supplied by the low-voltage battery, such as the drive level of the headlight. The correlation between the temperature level and the temperature level of the DC / DC converter is small.

  The present invention has been made in view of the above problems, and provides a dual-power-supply battery-equipped vehicle having a single fan type cooling device that can suppress an increase in size and power consumption of a cooling fan while complicating a circuit configuration. This is a problem to be solved.

  In order to solve the above-described problems, a cooling control device for a vehicle with a two-power-source battery according to the present invention includes a high-voltage rotating electrical machine controlled by the vehicle control device, a high-voltage battery that transmits and receives power, and each cell voltage of the high-voltage battery. A battery monitoring circuit that includes an A / D converter for converting to a digital signal, detects a state of the high-voltage battery based on each cell voltage, and transmits it to the vehicle control device; and a low-voltage for supplying low-voltage load from the high-voltage battery A step-down DC / DC converter for stepping down power transmission to the battery, a DC / DC converter control circuit for controlling the DC / DC converter based on a charge state of the low-voltage battery, and detecting the temperature of the high-voltage battery A high voltage battery temperature detection circuit for comparing with a first threshold, and a DC / DC converter temperature detection circuit for detecting the temperature of the DC / DC converter and comparing it with a second threshold. A cooling fan that supplies cooling air to the high-voltage battery and the DC / DC converter that are arranged close to or integrally with each other, and a cooling fan drive control circuit that controls driving of the cooling fan, the cooling fan drive control circuit Determines whether the temperature of the high-voltage battery is equal to or higher than a first threshold value, or whether the temperature of the DC / DC converter is equal to or higher than a second threshold value. The cooling fan is stopped when the temperature is lower than the first threshold and the temperature of the DC / DC converter is lower than the second threshold.

  That is, according to the present invention, the cooling fan that supplies cooling air to the high-voltage battery and the DC / DC converter to cool them is used when the temperature of the high-voltage battery exceeds the first threshold value or the temperature of the DC / DC converter. Is driven when the second threshold is exceeded.

  Thereby, a cooling system can be reduced in size and simplified by sharing a cooling fan and a cooling flow path. Furthermore, the cooling fan is driven individually corresponding to the cooling needs of the high voltage battery and the DC / DC converter that change in temperature almost independently of each other. Therefore, it is not necessary to turn on the cooling fan to a higher detection temperature compared to the conventional cooling fan control with a single ambient temperature, and as a result, the power consumption of the cooling fan can be reduced and the vehicle fuel consumption can be improved. it can.

  Note that the DC / DC converter and the high-voltage battery are separately arranged upstream and downstream of the common cooling air flow path, which is beneficial for downsizing and simplification of the ducts that constitute the cooling air flow path. In this case, the DC / DC converter is preferably arranged on the upstream side of the high voltage battery. This is because the amount of heat generated by the DC / DC converter is much smaller than the amount of heat generated by the high-voltage battery, and the influence on the temperature rise of the cooling air sent to the high-voltage battery is small. Of course, the DC / DC converter may be cooled after the high-voltage battery is cooled.

  In a preferred aspect, the battery monitor circuit, the DC / DC converter, the DC / DC converter control circuit, the DC / DC converter temperature detection circuit, and the cooling fan drive control circuit are integrally formed and housed in a common circuit case. The As a result, the circuit configuration can be simplified and the other circuits can be cooled simultaneously with the DC / DC converter, so that the DC / DC converter and the other circuits can be mounted with high density. Preferably, the DC / DC converter temperature detection circuit and the battery monitor circuit are mounted on a common circuit board. As a result, the length of the signal line for transmitting a signal from the DC / DC converter temperature detection circuit to the A / D converter can be shortened, so that noise and signal deterioration superimposed on the signal line can be reduced. Thus, it is possible to simplify the circuit configuration and the wiring configuration while ensuring the DC / DC converter temperature detection accuracy.

  In a preferred aspect, a constant voltage power supply unit that applies a common power supply voltage to the A / D converter and the two temperature detection circuits is provided, and the A / D converter of the battery monitor circuit outputs the two temperature detection circuits. The temperature signal voltage to be converted is converted into a digital signal. In this way, the power supply circuit can be simplified, and variations in the influence of the variable power supply voltage fluctuation on the digital conversion accuracy of the two temperature signals can be suppressed. Furthermore, since the outputs of the two temperature detection circuits are converted into digital signals by the A / D converter of the battery monitor circuit, the circuit configuration can be simplified, and the temperature detection of the high voltage battery and the DC / DC Circuit amplification errors and offset errors in the temperature detection of the DC converter can be reduced. In addition, connectors and wiring can be simplified.

  Note that the A / D converter can be of a type having a multiplexer at the front stage input section, and a routine for detecting each cell voltage of each high-voltage battery in time sequence can be executed at regular time intervals. In this case, the temperature of the high voltage battery and the temperature of the DC / DC converter are preferably implemented before or after the detection of each cell voltage. This is because each cell voltage is preferably detected as simultaneously as possible. Of course, by providing a plurality of A / D converters, the time required to detect all cell voltages and two temperatures may be shortened.

  In a preferred aspect, the cooling fan drive control circuit forcibly operates the cooling fan when the output of at least one of the temperature detection circuits is outside a predetermined range. As a result, either of the two temperature detection circuits deviates from an assumed detection temperature range (for example, −20 to 80 ° C.), for example, a failure of the temperature detection circuit, an abnormality in power supply to the temperature detection circuit, or A / D An abnormality of the converter can be determined, and the cooling fan drive is forcibly executed in accordance with the abnormality, so that overheating of the DC / DC converter and the high voltage battery can be prevented.

  In a preferred aspect, the cooling fan drive control circuit detects the high voltage battery detected when the temperature of the high voltage battery is equal to or higher than a first threshold value or when the temperature of the DC / DC converter is equal to or higher than a second threshold value. The first rotation value obtained from the relationship between the temperature of the high-voltage battery and the cooling fan rotational speed, and the detected temperature of the DC / DC converter as the temperature of the DC / DC converter and the cooling fan rotational speed. The second rotation value obtained from the relationship is obtained, and the cooling fan is driven at a higher rotation value of the two rotation values. If it does in this way, fuel consumption can be improved, preventing overheating of a DC / DC converter and a high voltage battery.

The preferred embodiment of the cooling control apparatus for a dual-power-source battery-equipped vehicle of the present invention applied to a hybrid vehicle will be specifically described by the following examples. However, the present invention is not limited to the following examples, and it is needless to say that other known techniques or techniques equivalent thereto can be combined.
(overall structure)
A circuit diagram of this embodiment is shown in FIG.

  1 is a battery pack, 2 is a low voltage battery (about 14V), 3 is a low voltage load connected in parallel with the low voltage battery 2, 4 is a thermistor for detecting the temperature of the low voltage battery, 5 is an ignition switch, 6 is an engine not shown It is a vehicle control device (vehicle ECU) for driving and controlling a generator driven by the engine and a travel motor for generating travel power.

  The battery pack 1 includes a high-voltage (300 to 400 V) high-voltage battery 11 that stores electric power for vehicle travel, a controller 12 that is a voltage converter with a battery state monitoring function, a cooling fan 13 with a built-in electric motor, and the temperature of the high-voltage battery. It consists of a thermistor C for detection and a thermistor D for temperature detection of a DC / DC converter, and is housed integrally in a battery pack case.

  The controller 12 includes a battery monitor 14, a step-down power transmission circuit 15, a fan drive circuit 16, and a power supply unit 17, and is accommodated in a common circuit case. Of the step-down power transmission circuit 15, a circuit excluding a DC / DC converter control circuit 158 to be described later is fixed to a metal base plate that forms a heat sink, and other circuits including the DC / DC converter control circuit 158 are parallel to the metal base plate. It is mounted on an installed printed circuit board and built in the circuit case.

  The battery monitor 14 includes an A / D converter 141, a microcomputer 142, a communication interface circuit 143 that performs signal multiplexing communication, and two load resistors 148 and 189.

  The step-down power transmission circuit 15 includes an input smoothing capacitor 151, a DC / DC converter temperature detection circuit 152, an inverter circuit 153, a step-down transformer 154, a diode full-wave rectifier circuit 155, a choke coil 156, an output smoothing capacitor 157, and a DC / DC converter control. A circuit 158 is included.

  The DC / DC converter control circuit 158 includes an output voltage command receiving unit 1581 that is an input I / O for receiving an output voltage command, an output voltage detecting unit 1582 that is an input I / O that detects a terminal voltage of a low-voltage battery, and PWM control. And a drive circuit 1584 that is a driver circuit that outputs a gate control voltage to the inverter circuit 153.

  Reference numeral 100 denotes a signal line for outputting the temperature of the inverter circuit 153 converted into a digital signal by the A / D converter 141 to the PWM control unit 1583.

  The input smoothing capacitor 151, the inverter circuit 153, the step-down transformer 154, the diode full-wave rectifier circuit 155, the choke coil 156, and the output smoothing capacitor 157 constitute the DC / DC converter referred to in the present invention.

  The load resistor 148 and the thermistor C for the high voltage battery 11 constitute a high voltage battery temperature detection circuit referred to in the present invention. The thermistor C for the high voltage battery 11 is closely fixed to the outer case covering the high voltage battery 11. The load resistor 149 and the thermistor 4 for detecting the low voltage battery temperature constitute a low voltage battery temperature detection circuit. The thermistor 4 is tightly fixed to the low voltage battery 2. The DC / DC converter temperature detection circuit 152 includes a thermistor D and a load resistor (numbering omitted) connected in series with the thermistor D. The thermistor D for DC / DC converter temperature detection is close to the inverter circuit 153 of the DC / DC converter. Are arranged. The thermistor D is fixed to the cooling fin (not shown) of the inverter circuit, but may be mounted on a circuit board arranged in the vicinity of the cooling fin. A predetermined constant power supply voltage of 5 V, for example, is applied to these three temperature detection circuits from the power supply unit 17.

The above-described controller 12 displays the circuit function. In practice, for example, as shown in FIG. 2, it is obvious that the circuit configuration may be shared by a microcomputer device or the like. The operation of each circuit described above will be described below. In FIG. 2, reference numeral 200 denotes a microcomputer incorporating a predetermined number of A / D converters, and 201 denotes a multiplexer that converts each cell voltage or each block voltage of the high-voltage battery 11 into a time-sequential voltage signal. The multiplexer may be built in the microcomputer.
(Description of operation)
The operation of the circuit of FIG. 1 will be described.

  The A / D converter 141 converts each cell voltage of the high voltage battery 11, the temperature of the high voltage battery 11, the temperature of the inverter circuit 153, the temperature of the low voltage battery 2, the input voltage and the output voltage of the step-down power transmission circuit 15 into digital signals in time order. The data is converted and output to the microcomputer 142. In order to shorten the detection time interval, the time required for one measurement may be shortened by arranging a plurality of A / D converters.

  The step-down power transmission circuit 15 is a well-known step-down DC / DC converter, and detailed description thereof will be omitted. The DC / DC converter control circuit 158 is configured by a hardware circuit or a microcomputer circuit. The output voltage command from the microcomputer 142 (in this embodiment, an analog value) is detected by the output voltage detection unit 1582. The voltage of the low voltage battery 2 is compared, and the inverter circuit 153 is PWM controlled through the drive circuit 1584 based on the comparison result.

  The microcomputer 142 transmits the charging status and temperature of the high-voltage battery 11 detected by the A / D converter 141 or a charging request signal for the high-voltage battery 11 based on the charging status and temperature to the vehicle ECU 6 through the signal multiplexing I / O 143. Further, the microcomputer 142 receives the signal multiplexing I / O 143 from the vehicle ECU 6 and transmits the DC / DC converter drive control command to the PWM control unit 1583 through the output voltage command receiving unit 1581.

  By the above operation, the charge / discharge level of the high voltage battery 11 and the step-down power transmission control from the high voltage battery 11 to the low voltage battery 2 are controlled, and the voltage and temperature of the high voltage battery 11 and the voltage and temperature of the low voltage battery are monitored. , Whether they are maintained within an acceptable range can be monitored.

(Cooling fan control)
Next, the cooling fan control which characterizes this embodiment will be described with reference to the flowchart shown in FIG.

  First, the temperature T1 of the high voltage battery 11 and the temperature T2 of the DC / DC converter (inverter circuit 153) are read (S100), and the temperature T1 is within a temperature range (TL to TH) that can be reached after the vehicle power is turned on. If it is within the range, it is checked whether the temperature T2 is within the temperature range (TL to TH) that can be reached after the vehicle power is turned on (S104). For example, −20 ° C. is used as TL, and 100 ° C. is used as TH.

  If the temperatures T1 and T2 are both within the temperature range (TL to TH), it is checked whether or not the temperature T1 exceeds a threshold temperature Tth1 (for example, 50 ° C.) that requires cooling of the high-voltage battery 11 by the cooling fan 13 (S106). If not, it is checked whether or not the temperature T2 exceeds a threshold temperature Tth2 (for example, 70 ° C.) that requires cooling of the inverter circuit 153 by the cooling fan 13 (S108). Then, the cooling fan 13 is turned off and the microcomputer 142 returns to the main routine (not shown).

  If one of the temperatures T1 and T2 exceeds the threshold temperature in step S106 or step S108, the cooling fan 13 is turned on in step 112 and the process returns to the main routine. If it is determined in step S102 that the temperature T1 has deviated from the temperature range, a high-voltage battery abnormality flag is output (S114), and the cooling fan 13 is turned on (S112). Similarly, if it is determined in step S104 that the temperature T2 has deviated from the temperature range, a DC / DC converter abnormality flag is output (S118), and the cooling fan 13 is turned on (S112).

(Cooling system configuration)
The configuration of the cooling system of this embodiment is shown in FIG.

  In FIG. 4, the duct 200 of the cooling fan 13 is formed, and the power unit 150 of the step-down power transmission circuit 15, the control unit 15 ′ of the step-down power transmission circuit 15, and the high-voltage battery 11 are accommodated in this order from the upstream side to the downstream side. Has been. Thereby, the inverter circuit 153 can be cooled favorably. Part or all of the duct 200 can also be configured by a vehicle body. Note that the cooling air from the cooling fan 13 may be supplied to the circuit and the high-voltage battery 11 separately (in parallel).

(Modification)
In the above embodiment, the cooling fan 13 is only on / off controlled. However, in the operation region of the cooling fan 13, the cooling fan 13 is cooled at a rotational speed having a positive correlation between the detected temperature T 1 of the high-voltage battery 11 and the temperature T 2 of the inverter circuit 153. You may add rotation speed control of the fan 13. FIG. In this case, it is preferable to perform the rotational speed control in conjunction with the higher temperature of the high-voltage battery 11 and the inverter circuit 153 with higher cooling performance.

(Example effect)
According to this embodiment, it is possible to reliably prevent overheating of the high-voltage battery and the DC / DC converter, and it is possible to improve vehicle fuel efficiency without consuming unnecessary power due to excessive fan operation.

  Further, the power supply voltage applied to the thermistor C and the thermistor D constituting the DC / DC converter temperature detection circuit and the high-voltage battery temperature detection circuit is the same, and is also shared with the power supply voltage of the A / D converter. The tendency of output fluctuation to each temperature due to fluctuation can be made the same, and the circuit can be simplified.

  Furthermore, since the control of the cooling fan is controlled by the microcomputer circuit forming the battery monitor 14 and the step-down power transmission circuit 15 disposed in the vicinity of the cooling fan, safety due to reduction of vehicle wires and disconnection is increased.

Furthermore, the calculation burden of the vehicle ECU 6 regarding battery management and step-down power transmission control can be reduced, and the communication burden between the vehicle ECU 6 and the microcomputer 142 can be reduced.
(Modification)
In the above embodiment, the cooling air formed by one cooling fan is shared by the high-voltage battery cooling and the DC / DC converter cooling, but the shared cooling air may be formed by a plurality of cooling fans. In this case, a mode for operating only a part of the cooling fans and a mode for operating all the cooling fans may be provided according to the necessity of cooling.

It is a circuit diagram which shows one Example of this invention. It is a circuit diagram which shows the deformation | transformation aspect of FIG. It is a flowchart which shows the cooling fan control of this Example. It is a model arrangement drawing which shows an example of a structure of a cooling system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Battery pack 2 Low voltage battery 3 Low voltage load 4 Thermistor 6 Vehicle ECU (vehicle control device)
DESCRIPTION OF SYMBOLS 11 High voltage battery 12 Controller 13 Cooling fan 14 Battery monitor 15 Step-down power transmission circuit 16 Fan drive circuit 17 Power supply part 141 Converter 142 Microcomputer 143 Communication interface circuit 150 Power part 150 'Control part 151 Input smoothing capacitor 152 Converter temperature detection circuit (DC / DC Converter temperature detection circuit)
153 Inverter circuit 154 Step-down transformer 155 Diode full-wave rectifier circuit 156 Choke coil 157 Output smoothing capacitor 158 Converter control circuit 1581 Output voltage command receiver 1582 Output voltage detector 1583 Controller 1584 Drive circuit 200 Duct

Claims (7)

A high-voltage rotating electrical machine controlled by a vehicle control device and a high-voltage battery for transferring power;
A battery monitor circuit that includes an A / D converter that converts each cell voltage of the high-voltage battery into a digital signal and detects the state of the high-voltage battery based on the cell voltage and transmits the detected voltage to the vehicle control device;
A step-down DC / DC converter for stepping down power from the high-voltage battery to a low-voltage battery for low-voltage load feeding;
A DC / DC converter control circuit for controlling the DC / DC converter based on a state of charge of the low-voltage battery;
A high voltage battery temperature detection circuit for detecting the temperature of the high voltage battery and comparing it with a first threshold;
A DC / DC converter temperature detection circuit for detecting the temperature of the DC / DC converter and comparing it with a second threshold;
A cooling fan that provides cooling air to both the high-voltage battery and the DC / DC converter, which are arranged close to or integrally with each other;
A cooling fan drive control circuit for controlling the driving of the cooling fan;
With
The cooling fan drive control circuit includes:
It is determined whether the temperature of the high-voltage battery is equal to or higher than a first threshold value or the temperature of the DC / DC converter is equal to or higher than a second threshold value. When the temperature of the DC / DC converter is less than a second threshold and the temperature of the DC / DC converter is less than a second threshold, the cooling fan is stopped. The cooling control apparatus for a vehicle with a dual power source battery according to claim 1,
The battery monitor circuit, the DC / DC converter, the DC / DC converter control circuit, the DC / DC converter temperature detection circuit, and the cooling fan drive control circuit are integrally formed and housed in a common circuit case. A cooling control device for a vehicle equipped with a two power source battery. The cooling control apparatus for a vehicle with a dual power source battery according to claim 2,
A constant voltage power supply unit that applies a common power supply voltage to the A / D converter and the temperature detection circuits;
The A / D converter of the battery monitor circuit converts the temperature signal voltage output from the two temperature detection circuits into a digital signal, and is a cooling control device for a vehicle with a two-power-source battery. The cooling control apparatus for a vehicle with a dual power source battery according to claim 1,
The cooling fan drive control circuit includes:
A cooling control apparatus for a vehicle with a two-power-supply type battery, wherein the cooling fan is forcibly operated when the output of at least one of the temperature detection circuits is outside a predetermined range. The cooling control apparatus for a vehicle with a dual power source battery according to claim 1,
The cooling fan drive control circuit includes:
When the temperature of the high-voltage battery is equal to or higher than the first threshold value or the temperature of the DC / DC converter is equal to or higher than the second threshold value, the detected temperature of the high-voltage battery is set to the temperature of the high-voltage battery and the rotation speed of the cooling fan. And the second rotation value obtained from the relationship between the temperature of the DC / DC converter and the cooling fan rotation number, and the first rotation value obtained from the relationship between And the cooling fan is driven at a higher rotational value of the both rotational numerical values. The cooling control apparatus for a vehicle with a dual power source battery according to claim 1,
The high voltage battery temperature detection circuit includes:
2. A cooling control apparatus for a vehicle with a two-power-source battery, comprising a temperature sensor fixed to a heat radiating fin of the DC / DC converter or a control board in the vicinity of the heat radiating fin. The cooling control apparatus for a vehicle with a dual power source battery according to claim 1,
The DC / DC converter temperature detection circuit includes:
A cooling control device for a vehicle with a two-power-source battery, comprising a temperature sensor fixed to the case or electrode terminal of the high-voltage battery.

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