JP2002042906A - Battery voltage detector and hybrid vehicle control device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery voltage detector for efficiently detecting cell voltages and a hybrid vehicle control device for preventing the deterioration of the whole battery due to excessive charge/discharge of cells by controlling the charge/discharge of the battery in accordance with the cell voltages detected by the battery voltage detector. SOLUTION: A CPU 40 connects analog switches in multiplexers 20a, 20b, 20c to all cells constituting corresponding modules 1a, 1b, 1c in sequence at starting of a battery voltage detector to acquire the voltages of all cells constituting the battery 1 and transmit the acquired cell voltages to the external control device. On the other hand, after starting the detector, the voltages of the cells showing the maximum cell voltage and the minimum cell voltage out of the cell voltages acquired at starting are only detected at preset intervals and the detected cell voltages are output to the external control device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery voltage detecting device for detecting the voltage of each cell in a power storage device composed of a plurality of cells, and more particularly to a power storage device used for electric vehicles and hybrid vehicles. The present invention relates to a battery voltage detection device for efficiently detecting a cell voltage and a control device for a hybrid vehicle using the device.

[0002]

2. Description of the Related Art A hybrid vehicle that travels by combining driving by a motor and driving by an engine in accordance with the driving state is a high-voltage battery (hereinafter, referred to as a battery) comprising a plurality of cells.
Abbreviated as a battery). In this hybrid vehicle, when starting and accelerating the vehicle,
By supplying the energy stored in the battery to the motor, the driving of the engine is assisted by the motor, and when the vehicle is decelerated, the battery is charged by the regenerative operation of the motor. In the above battery, if charge / discharge is performed without considering the remaining capacity of the cell, charge / discharge is performed beyond the allowable range of the cell, so-called overcharge / discharge of the cell occurs, and deterioration of the battery as a whole is caused. Will cause it. As a result, there is an adverse effect that the life of the battery pack is shortened and other systems are hindered. Therefore, it is necessary to monitor the remaining capacity (or cell voltage) of each cell and control the charge / discharge of the battery according to the remaining capacity of each cell in order to prevent the deterioration of the battery caused by the above-described causes. is there.

[0003]

Conventionally, in order to protect the battery as described above, an A / D converter-integrated microcomputer is provided for each module composed of a plurality of cells, and the detected cell voltages are used. A method has been used in which the data is transmitted by serial communication to a higher-level control unit through a microcomputer, and the charging and discharging of the battery is controlled by the higher-level control unit. However, the above-described conventional method has a problem that the number of microcomputers must be increased with an increase in the number of cells of the battery, which causes an increase in cost. In addition, if the voltages of all the cells constituting the battery are transmitted to a higher-level control unit by serial communication, it takes time for data communication, and it takes time until the detected cell voltage is reflected in vehicle control. There was a disadvantage.

[0004] The present invention has been made in view of such circumstances, and a battery voltage detecting device for efficiently detecting a cell voltage, and charging of a battery based on the cell voltage detected by the battery voltage detecting device. An object of the present invention is to provide a control device for a hybrid vehicle that controls discharge to prevent deterioration of the entire battery due to overcharging and discharging of cells.

[0005]

In order to achieve the above object, the present invention relates to a module comprising a plurality of modules (1a, 1b, 1c ... in the embodiment) each having a plurality of cells connected in series. A battery voltage detection device (in the embodiment, the battery voltage detection device 10) that detects the voltage of each cell of the power storage device (in the embodiment, the battery 1). Detectable voltage detecting means (in the embodiment, multiplexers 20a, 20b2
0c ... and A / D converters 30a, 30b, 30c ...)
And a cell specifying means for specifying a cell showing the maximum value and the minimum value among the cell voltages detected by the voltage detecting means (in the embodiment, the CPU 40 has the processing and corresponds to step SA2 in FIG. 2). And a storage unit (in the embodiment, the CPU 40 has) for storing the cell, wherein the voltage detection unit, after the cell is specified by the cell specification unit, the voltage of the specified cell (According to the embodiment, the maximum cell voltage Vmax and the minimum cell voltage Vmin) or the voltage of each cell constituting the module including the specified cell is detected at predetermined intervals.

Specifically, the battery voltage detecting device of the present invention has a function of detecting all the cell voltages constituting the power storage device. First, at the time of starting the device, all the cell voltages are detected. The maximum cell voltage Vmax and the minimum cell voltage Vmin are extracted from the detected cell voltages, and the addresses of the cells indicating these voltage values are stored. Then, after the address of the cell is stored, that is, after the device is started, the maximum cell voltage Vmax and the minimum cell voltage Vm
The voltage of the cell indicating "in" or the voltage of each cell constituting the module including these cells is monitored at predetermined intervals. Thereby, after the start of the device, the number of cells for detecting the voltage is reduced as compared with the related art, so that the detection time of the cell voltage and the time required for transmitting the detected cell voltage can be significantly reduced, Battery charge / discharge control can be performed efficiently.

Further, according to the battery voltage detecting device having the above structure, the voltage detecting means detects all the cell voltages constituting the power storage device at the time of starting the battery voltage detecting device, and the cell specifying means includes: And comparing all the cell voltages detected by the voltage detecting means to specify a cell having the maximum cell voltage and a cell having the minimum cell voltage. According to the above configuration, all cell voltages are detected at the time of starting the device, that is, in a state where no current is flowing, so that an accurate cell voltage can be detected.

Further, according to the battery voltage detecting device having the above configuration, the voltage detecting means detects the current flowing through the power storage device (in the embodiment, the current is detected by a current sensor (not shown) provided in the battery 1). Value) is smaller than a predetermined value (in the embodiment, when the current of the battery 1 is smaller than the cruise determination current Ip), all the cell voltages constituting the power storage device are detected, and the cell identification is performed. The means compares all the cell voltages detected by the voltage detecting means, and specifies a cell indicating the maximum cell voltage and a cell indicating the minimum cell voltage. That is, when the current flowing through the power storage device is small, the temporal transition of the cell voltage constituting the power storage device becomes slow as shown in FIG. Therefore, in such a situation, the battery voltage detection device may set a longer interval for monitoring the cell voltage. As described above, when there is room for voltage detection, the states of all the cells can be grasped by detecting the voltages of all the cells constituting the power storage device. In addition, when no difference is found in all the cell voltages at the time of the previous all-cell voltage detection, the cell indicating the maximum cell voltage Vmax and the minimum cell voltage Vmin may be replaced during the operation of the power storage device. . Even in such a case, if there is a margin in the voltage detection, all the cell voltages are detected, and the cells showing the maximum voltage value and the minimum voltage value are newly specified to more accurately charge the battery. It is possible to control the discharge.

Further, the present invention comprises an engine and a motor as a driving source of a vehicle, and comprises a plurality of cells for supplying electric power to the motor and storing energy obtained by power generation or regenerative operation of the motor when the vehicle is decelerated. A control device for a hybrid vehicle, comprising: a battery voltage detecting device according to any one of claims 1 to 3 as a device for managing the voltage of each cell of the power storage device. Here, the battery control device 5, the motor control device 6, and the engine control device 7) are based on the cell voltages (in the embodiment, the maximum cell voltage Vmax and the minimum cell voltage Vmin) detected by the battery voltage detection device. Controlling charging and discharging of the power storage device (in the embodiment, prohibition of regeneration of the motor or prohibition of assist of engine output by the motor). To.

Specifically, when the maximum cell voltage Vmax detected by the battery voltage detecting means is equal to or higher than a preset charging limit voltage V1, the control device of the hybrid vehicle controls the motor 4 When the regenerative operation is prohibited, charging of the battery 1 is prohibited. When the minimum cell voltage Vmin detected by the battery voltage detecting device 10 is equal to or less than a preset discharge limiting voltage V2, The power supply to the motor by the battery 1 is prohibited. As described above, charging / discharging of the power storage device is controlled based on the cell voltage detected by the battery voltage detection device, so that the cells constituting the power storage device can be controlled to charge / discharge within an allowable range.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. Here, as an embodiment of the present invention, a case where the battery voltage detecting device of the present invention is applied to a parallel hybrid vehicle will be described. First, a parallel hybrid vehicle will be schematically described with reference to FIG.

In FIG. 5, a battery 1 is a high-voltage battery. This battery 1 is configured by connecting a plurality of cells in series with a plurality of cells connected in series as one unit. In recent years, lithium-ion batteries have been favorably used as the cells. This is because lithium-ion batteries have a relatively high electromotive force, a high energy density, so that the batteries can be reduced in size and weight, and the operating temperature range is as wide as -55 ° C to 85 ° C. This is because the usability is good.

The battery 1 is provided with a current sensor (not shown) for detecting a battery current and a temperature sensor (not shown) for detecting a battery temperature. The battery current and the battery temperature output by these sensors are provided. Is output to the battery control device 5 and used as a parameter used for vehicle control. The battery voltage detection device 10 includes:
The cell voltage of the battery 1 is detected at predetermined intervals, and the detected cell voltage is output to the battery control device 5. Details of the battery voltage detection device 10 will be described later.

The engine 3 operates with the combustion energy of fuel, and the motor 4 is used in combination with the engine 3 and operates with electric energy. The driving force of both the engine 3 and the motor 4 is transmitted to driving wheels (not shown) via a transmission (not shown) composed of an automatic transmission or a manual transmission. When the hybrid vehicle is decelerated, the driving force is transmitted from the driving wheels to the motor 4, and the motor 4 functions as a generator, generates a so-called regenerative braking force, and charges the battery 1.

The drive and regeneration of the motor 4 are controlled by the power drive unit 2 in response to a control command from the motor control device 6.
Is performed by Specifically, the power drive unit 2 is configured by connecting two switching elements in series and three in parallel, and the switching elements are turned on and off by the motor control device 6 to thereby control the battery 1. From the motor 4 via the three-phase wire
Or the regenerative power of the motor 4 is supplied to the battery 1.

The engine control device 7 controls the amount of fuel supplied to the engine 3, operates a starter motor (not shown), and controls ignition timing and the like. For this purpose, information on the remaining battery charge SOC from the battery control device 5, information on the motor 4 from the motor control device 6, and signals from various sensors provided in the engine 3 are supplied to the engine control device 7. . Various sensors include a vehicle speed sensor (not shown) for detecting a vehicle speed, a water temperature sensor (not shown) for detecting an engine water temperature, a throttle opening sensor (not shown) for detecting a throttle opening, and a suction sensor for detecting an engine intake temperature. Temperature (not shown) and the like are listed.

Then, based on the above-mentioned signals, the engine control unit 7 determines a mode such as fuel cut, engine start timing, motor regeneration, assist, deceleration, and the like. The battery control device 5, the motor control device 6, and the engine control device 7 are configured by a CPU (Central Processing Unit) and a memory, and realize the functions by executing a program for realizing the functions of the control device. .

Next, a battery voltage detecting device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the internal configuration of the battery voltage detection device according to one embodiment of the present invention. In FIG. 1, a battery 1 includes joules 1a, 1
., 1c... are connected in series. Here, it is assumed that each module is configured by connecting four cells in series.

Each of the modules 1a, 1b, 1c,.
Correspond to the multiplexers 20a and 20a, respectively.
b, 20c... are provided. Multiplexer 20
a, 20b, 20c... are IC chips having a plurality of built-in analog switches. The channels connected to the analog switches are sequentially switched to change the voltages of the connected cells to corresponding A / D (analog / digital).
Are output to the converters 30a, 30b, 30c...

A / D converters 30a, 30b, 30c ...
Converts the input analog cell voltage into a digital value and outputs the digital value to the CPU 40. The CPU 40 has a storage unit therein, and performs various processes by executing programs stored in the storage unit.

Next, the operation of the battery voltage detecting device having the above configuration will be described with reference to FIGS. First,
The operation of the battery voltage detecting device when the vehicle equipped with the battery voltage detecting device starts running (ignition ON) will be described with reference to FIG.

When the ignition is turned on, the CPU 40 in the battery voltage detecting device 10
By sequentially switching the analog switches 0a, 20b, 20c,..., The corresponding modules 1a,
1b, 1c,... Are connected to all the cells constituting the cells, and the respective cell voltages are output to the A / D converter 30a. Then, the above operation is performed by the multiplexers 20a, 20b, 20
By performing c ... in parallel, the A / D converter 30a,
30b, 30c...
, 1c... are sequentially input.

A / D converters 30a, 30b, 30c ...
Converts an analog voltage value inputted one after another into a digital value, and outputs the digital value to the CPU 40 every time it is converted. Thereby, each A /
Cell voltages, which are digital values, are successively input from the D converters 30a, 30b, 30c. And battery 1
Are all digital data as C
When input to the PU 40, the CPU 40 stores all the input cell voltages in a predetermined area of the storage unit in the CPU 40 (step SA1 in FIG. 2).

Subsequently, the CPU 40 selects the maximum cell voltage Vmax and the minimum cell voltage Vmax from the inputted total cell voltages.
min, and the address of the cell showing these values is
It is stored in a predetermined area of a storage unit provided in the PU 40 (step SA2). Thereafter, the CPU 40 transmits the all cell voltages obtained in step SA1 to the battery control device 5 (step SA3).

In the above description, among the cells constituting the battery 1, the maximum cell voltage Vmax and the minimum cell voltage Vmax
After specifying the cell indicating min, all cell voltages are transmitted. After transmitting all cell voltages, the cell indicating the maximum cell voltage Vmax and the minimum cell voltage Vmin is specified and stored. The timing for transmitting the cell voltage is not particularly limited.

Next, the operation of the battery voltage detecting device while the vehicle is running will be described with reference to FIG. First, C
The PU 40 has a maximum voltage value Vmax and a minimum voltage value Vmi.
n is detected (step SC in FIG. 3).
1). Now, for example, in step SA2 of FIG. 2, of the cells constituting the module 1a,
The cell arranged second from the top is the maximum cell voltage Vm.
ax, and among the cells constituting the module 1b, the third cell from the top, with the positive electrode side as the top, shows the minimum cell voltage Vmin. In this case, the CPU 40 connects the analog switch of the multiplexer 20a to the second cell from the top, connects the analog switch of the multiplexer 20b to the third cell from the top, and turns off the analog switches of the other multiplexers. And

Thus, the A / D converter 30a and the A / D
The cell voltage is input to the D converter 30b via the multiplexers 20a and 20b, respectively. The A / D converters 30a and 30b convert the input voltages into digital values and output the digital values to the CPU 40. This allows
The CPU 40 acquires the second cell voltage from the top of the module 1a, that is, the maximum cell voltage Vmax, and the third cell voltage from the top of the module 2a, that is, the minimum cell voltage Vmin.

Subsequently, the CPU 40 stores the obtained maximum cell voltage Vmax and minimum cell voltage Vmin in predetermined areas of the storage unit, and outputs these values to the battery control device 5 (step SC2 in FIG. 3). And C
The PU 40 performs step SC1 and step SC2 described above.
Is repeatedly executed at predetermined intervals. in this way,
Every predetermined time, the CPU 40 controls the multiplexer and the A / D
The cell voltage is read via the converter, and the maximum cell voltage Vmax and the minimum cell voltage Vmin of the battery 1 are monitored at predetermined intervals.

In the above description, the CPU 40 is set so as to detect only the maximum cell voltage Vmax and the minimum cell voltage Vmin while the vehicle is running. However, the CPU 40 detects the maximum cell voltage Vmax and the minimum cell voltage Vmi.
You may make it read the voltage of each cell which comprises the module containing the cell which showed n. That is, the CPU 40 includes the multiplexers 20a and 20b in the specific example described above.
By sequentially switching the microswitches, the voltages of all the cells constituting the module 1a and all the cells constituting the module 1b may be detected.
At this time, the multiplexers 20a and 20b operate simultaneously in parallel.

Next, the operation of the control device for a hybrid vehicle according to one embodiment of the present invention, which is performed using the voltage value detected by the above-described battery voltage detection device 10, will be described.

First, when the ignition is turned on, that is, when the vehicle starts running, the battery control device 5 acquires all the cell voltages of the battery 1 from the battery voltage detection device 10. Further, the battery control device 5 acquires a battery current and a battery temperature from a current sensor and a temperature sensor provided in the battery 1. Then, the battery control device 5 calculates the remaining capacity of the battery 1 at the start of traveling based on the acquired all cell voltages, battery currents, and battery temperatures of the battery 1, and controls the calculated remaining capacity of the battery 1 by engine control. Transmit to the device 7. In this way,
The voltage value detected by the battery voltage detection device 10 is reflected on vehicle control. Although various methods have been proposed for calculating the remaining capacity of the battery 1 described above, the description is omitted because it is not directly related to the present invention.

Next, the operation of the control device of the hybrid vehicle while the vehicle is running, here, mainly the operation of the battery control device will be described with reference to FIG. First, during traveling, the battery voltage detecting device 10 detects the maximum cell voltage Vmax and the minimum cell voltage Vmin of the battery 1 at predetermined intervals as described above, and transmits these values to the battery control device 5.

When the battery control device 5 obtains the maximum cell voltage Vmax and the minimum cell voltage Vmin (step SB1 in FIG. 4), it determines whether or not the obtained maximum cell voltage Vmax is equal to or higher than the charging limit voltage V1. (Step SB2). As a result, if the maximum cell voltage Vmax is equal to or higher than the charging limit voltage V1, control is performed to prohibit the regenerative operation of the motor 4 (step SB3), and thereafter, the present process ends. Specifically, the battery control device 5 transmits a signal for inhibiting the regenerative operation to the motor control device 6, whereby the motor control device 6 inhibits the regenerative operation of the motor.

On the other hand, if the maximum cell voltage Vmax has not reached the charging limit voltage V1 in step SB2 in FIG. 4, it is determined whether the minimum cell voltage Vmin obtained in step SB1 is equal to or lower than the discharge limiting voltage V2. A determination is made (step SB4). As a result, the minimum cell voltage V
If min is equal to or lower than the discharge limit voltage V2, control is performed to prohibit the assist of supplying the energy of the battery 1 to the motor 4 (step SB5), and the process ends. Here, too, the battery control device 5 does not perform the control to prohibit the assist, but the battery control device 5.
Transmits a signal requesting prohibition of assist to the motor control device 6, so that the motor control device 6 finally prohibits power supply to the motor 4. On the other hand, if the minimum cell voltage Vmin is higher than the discharge limit voltage V2 in step SB4, the process ends.

As described above, of the cells constituting the battery 1, the voltage of the cell which is considered to reach the overcharge region first (the maximum cell voltage Vmax) and the voltage of the cell which is considered to reach the overdischarge region first (the voltage (maximum)) By monitoring the minimum cell voltage Vmin) at predetermined intervals, it is possible to monitor whether or not other cells are actually operating within the allowable range.

In the present embodiment, when the vehicle is running, the cells detected by the battery voltage detector 10 are two cells, a cell indicating the maximum cell voltage Vmax and a cell indicating the minimum cell voltage Vmin. Although the charge and discharge control of the battery 1 is efficiently performed by detecting these cell voltages in a limited manner, the following control may be performed as another embodiment instead of this. First, FIG. 6 shows an example of a temporal change of the cell voltage at the time of regeneration and assist, and FIG. 7 shows an example of a temporal change of the cell voltage at the time of cruise. As can be seen from the figure, during regeneration and during assist, the charging / discharging current to the battery 1 is large, so that the temporal change of the cell voltage is large.
For this reason, the cell voltage is within the allowable range L (charge limit voltage V1
Below and above the discharge limit voltage V2).
It is necessary for the battery voltage detector to frequently monitor the cell voltage and manage the charge and discharge of the battery. On the other hand, at the time of cruise, the charge / discharge current flowing through the battery 1 is smaller than at the time of regeneration and at the time of assist, so that the temporal change of the cell voltage is gradual. Therefore, in such a situation, the battery voltage detection device may set a longer interval for monitoring the cell voltage.

The operation of the battery voltage detecting device according to another embodiment of the present invention detects the cell voltage of the battery 1 in consideration of the condition of the battery 1 according to the running condition of the vehicle as described above. Hereinafter, an operation of the battery voltage detection device 10 according to another embodiment when the hybrid vehicle travels will be described with reference to FIG.

First, while the vehicle is running, it is determined whether or not the current running state of the hybrid vehicle is cruise running (step SD1 in FIG. 8). The determination as to whether or not this is craze travel can be identified by a signal input from any of the battery control device 5, the motor control device 6, and the engine control device 7. For example, when the battery current detected by the current sensor provided on the battery 1 is smaller than the cruise determination current Ip, the battery control device determines that the vehicle is traveling cruise. In addition, the motor control device can determine whether or not the vehicle 4 is cruising based on the operation state of the motor 4. In addition, the engine control device 7 determines that the vehicle is cruising when the throttle opening is not fully closed and is equal to or less than the assist trigger threshold.

The CPU in the battery voltage detecting device 10
A signal indicating whether or not the vehicle is traveling on a cruise is transmitted to 40 by any of the control devices described above. Battery voltage detector 1
The CPU 40 within 0 determines whether or not the current traveling of the vehicle is a cruise traveling by determining the received signal. As a result, when it is determined that the vehicle is not cruising, the voltages of the cell indicating the minimum cell voltage Vmin and the cell indicating the maximum cell voltage Vmax stored in a predetermined area of the storage unit in the CPU 40 are detected. (Step SD2) The detected cell voltage is stored in the battery controller 5
(Step SD4).

On the other hand, if it is determined in step SD1 that the current vehicle traveling state is cruise traveling, voltages are detected for all cells constituting the battery 1 (step SD3). Specifically, the same processing as the processing performed when the apparatus is started (steps SA1 to SA3 in FIG. 2) is performed. That is, when all the cell voltages are detected, the maximum cell voltage Vma is selected from among the detected all cell voltages.
x and the minimum cell voltage Vmin are extracted, and the address of the cell indicating these values is stored in a predetermined area of the storage unit.
That is, the address of the cell is updated. Subsequently, the CPU 40
Transmits the acquired all cell voltages to the battery control device 5 (step SD4).

As described above, in other embodiments, during regeneration and assist when frequent cell voltage detection is required, the cell whose voltage is to be detected is set to the cell having the maximum voltage value and the cell having the minimum voltage value. , And monitoring these cells at as short a time interval as possible prevents overcharging and discharging of the cells. Then, the cell voltage of the battery 1 does not change suddenly, and the cell voltage detection can have a margin. That is, at the time of cruising when the monitoring interval may be set relatively long, all the cell voltages constituting the battery 1 are changed. Is detected. As a result, more accurate cell voltages can be transmitted to the battery control device 5 during a cruise, and these voltages are reflected in vehicle control.

Also, at the time of the previous all-cell voltage detection,
If there is no difference between all the cell voltages, the cell indicating the maximum cell voltage Vmax and the minimum cell voltage Vmin may be replaced during running of the vehicle. Even in such a case, during the cruise, all the voltage values are scanned, and the cells showing the new maximum voltage value and the minimum voltage value are newly identified from the detected voltage values, so that the battery charging / discharging can be performed more accurately. Control can be performed. As described above, by changing the cell whose voltage is to be detected in accordance with the traveling state of the vehicle, it is possible to more efficiently and more accurately control the charge and discharge of the battery. In the above description, the determination as to whether the vehicle is cruising or not is made based on a signal from an externally provided control device.
If the configuration is such that the information of the current sensor provided in the battery is input, the battery voltage detecting device detects the voltage of all cells in consideration of the input current value without receiving an external signal. It is possible to determine whether or not to perform.
Further, as an example of the case where the current flowing to the battery 1 is small, the case of cruise running has been described. However, the present invention is not limited to the case of cruising, but if the current flowing to the battery 1 is small and the temporal change of the cell voltage is gradual, It is possible to detect the voltage of all cells.

The embodiment described above is an example for describing the present invention, and the present invention is not limited to the above embodiment, and various modifications are possible within the scope of the invention. is there. In the present embodiment, the battery voltage detection device is provided outside the battery control device. However, the processing performed by the CPU in the battery voltage detection device is performed by the battery control device 5.
It is also possible to integrate both CPUs by causing the CPUs inside to process. In this case, the number of CPUs can be reduced to one, and the cost can be reduced. Further, in the present embodiment, a multiplexer is used as the multi-channel switching means, but the present invention is not limited to this as long as it is another channel type switching device. The number of cells targeted by one multiplexer is determined by the withstand voltage of the multiplexer.

[0044]

As described above, according to the battery voltage detecting device of the present invention, the voltage detecting means capable of detecting all the cell voltages constituting the power storage device and the cell voltage of the cell voltage detected by the voltage detecting means are detected. And a storage unit for specifying the cell indicating the maximum value and the minimum value, and storing the cell. The voltage detection unit specifies the cell indicating the maximum value and the minimum value after the cell indicating the maximum value and the minimum value is specified. The voltage of the specified cell or the voltage of each cell constituting a module including the specified cell is detected at predetermined intervals.

As a result, since the number of cells for detecting the voltage is reduced after the start of the apparatus as compared with the prior art, the time required for detecting the cell voltage and the time required for transmitting the detected cell voltage can be significantly reduced. Can be. Thus, the protection performance of the power storage device is improved. Further, when the amount of change in the cell voltage with time is large and the cell voltage needs to be constantly monitored, the cell voltage can be detected more frequently than in the conventional case, which is a great effect for protecting the power storage device. Play.

According to the battery voltage detecting device of the present invention, the voltage detecting means detects all the cell voltages constituting the power storage device when the battery voltage detecting device is started, and the cell specifying means detects the voltage. By comparing all the cell voltages detected by the means, the cell showing the maximum cell voltage and the cell showing the minimum cell voltage are specified. Accordingly, a cell serving as an index for grasping the state of the power storage device after the start can be accurately specified, and an effect that the power storage device can be protected from overcharging and discharging.

According to the battery voltage detecting device having the above configuration, even after the operation of the power storage device is started, when the current flowing through the power storage device is relatively small, all the cell voltages constituting the power storage device are detected. It is possible to more accurately grasp the states of all cells included in the power storage device. Also,
If there is no difference between all the cell voltages at the previous detection of all the cell voltages, the cell indicating the maximum cell voltage Vmax and the minimum cell voltage Vmin may be replaced during the operation of the power storage device. Even in such a case, if there is room for voltage detection, all cell voltages are detected,
By specifying a new cell showing the maximum voltage value and the minimum voltage value, it is possible to more accurately control the charge and discharge of the battery. As a result, there is an effect that the power storage device can be accurately protected from a deterioration cause such as overcharging and discharging.

Further, the present invention comprises an engine and a motor as driving sources of a vehicle, and comprises a plurality of cells for supplying power to the motor and storing energy obtained by regenerative operation of the motor when generating or decelerating the vehicle. A control device for a hybrid vehicle having the battery voltage detection device according to claim 1, further comprising a power storage device, and further comprising a device for managing a voltage of each cell of the power storage device, wherein the cell detected by the battery voltage detection device is provided. The charge and discharge of the power storage device are controlled based on the voltage. In this manner, by prohibiting regeneration and assist in accordance with the cell voltage of the power storage device, the power storage device can be prevented from being overcharged and discharged, and the power storage device can be efficiently protected from deterioration. can get.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a battery voltage detection device according to an embodiment of the present invention.

FIG. 2 is an operation flowchart when the operation of the battery voltage detection device according to the embodiment is started.

FIG. 3 is an operation flowchart of the battery voltage detection device according to the embodiment after the operation is started.

FIG. 4 is an operation flowchart executed by the control device of the hybrid vehicle.

FIG. 5 is a block diagram illustrating a configuration example of a hybrid vehicle.

FIG. 6 is a characteristic diagram showing a transition of a cell voltage of a battery during regeneration and during assist in a hybrid vehicle.

FIG. 7 is a characteristic diagram showing a change in cell voltage of a battery during a cruise in a hybrid vehicle.

FIG. 8 is an operation flowchart showing an operation of a battery voltage detection device according to another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Battery (power storage device) 1a, 1b, 1c ... Module 3 Engine 4 Motor 5 Battery control device 10 Battery voltage detection device 20a, 20b, 20c ... Multiplexer (voltage detection means) 30a, 30b, 30c ... A / D converter ( Voltage detecting means) 40 CPU (cell specifying means and storage means)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H02J 7/02 H02J 7/02 H (72) Inventor Yasuo Yamada 1-4-1 Chuo, Wako-shi, Saitama F-term in Honda R & D Co., Ltd. (reference) 2G016 CA03 CB12 CB13 CC01 CC03 CC04 CC07 CC12 CC16 CC24 CC27 CC28 CE31 CF06 5G003 AA07 BA03 DA07 FA06 FA08 GC05 5H030 AA01 AS08 BB10 FF43 FF44 5H115 PA15 PG04 PI16 PU06 SE06 TI05

Claims (4)

[Claims] 1. A battery voltage detection device for detecting a voltage of each cell of a power storage device configured by connecting a plurality of cells connected in series to a plurality of modules, wherein all of the power storage devices are configured. A voltage detecting means capable of detecting a cell voltage; a cell specifying means for specifying a cell showing a maximum value and a minimum value among the cell voltages detected by the voltage detecting means; Storage means for storing a cell; andthe voltage detection means, after the cell is specified by the cell specification means, a voltage of the specified cell or a module including the specified cell. A battery voltage detecting device for detecting the voltage of each of the constituent cells at predetermined intervals. 2. The voltage detecting means detects all cell voltages constituting the power storage device at the time of starting the battery voltage detecting device, and the cell specifying means detects all cells detected by the voltage detecting means. 2. The battery voltage detection device according to claim 1, wherein voltages are compared to identify a cell indicating a maximum cell voltage and a cell indicating a minimum cell voltage. 3. The method according to claim 1, wherein the voltage detecting unit detects all cell voltages constituting the power storage device when a current flowing through the power storage device is smaller than a predetermined electric value. 3. The battery voltage according to claim 1, wherein all the cell voltages detected by the voltage detecting means are compared, and a cell indicating a maximum cell voltage and a cell indicating a minimum cell voltage are specified. Detection device. 4. A power storage device including an engine and a motor as driving sources of a vehicle, and a plurality of cells configured to store power obtained by power supply to the motor and energy obtained by regenerative operation of the motor during power generation or vehicle deceleration. A control device for a hybrid vehicle, comprising: the battery voltage detection device according to claim 1, further comprising: a device that manages a voltage of each cell of the power storage device. A control device for a hybrid vehicle, which controls charging and discharging of the power storage device based on a cell voltage detected by a detection device.