JP2000013917A - Controller for battery pack of electric automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve operability of a battery module without damaging the safety of the module by estimating the terminal voltage of the module detected by means of an abnormal detecting circuit system from prestored data when the abnormality in the circuit system is detected. SOLUTION: Each voltage detecting line 301-321 is extended from each terminal of each battery module 101-120 and differential amplifiers 201-220 are module voltage detecting means. In addition, a CPU 1 constitutes an abnormal detecting circuit judging means and a charge/discharge control means. Firstly, the CPU 1 reads the terminal voltages Vi of the modules 101-120 one after another from the amplifiers 201-220 and judges the abnormality of each detecting circuit system from the voltages Vi. The abnormality of each detecting circuit system is judged when the lowering rate of the terminal voltage of the circuit system is smaller than a prescribed value in a prescribed period of time when a prescribed current or larger is discharged or the value of the terminal voltage deviates from a prescribed range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a control device for an assembled battery for an electric vehicle.

[0002]

2. Description of the Related Art In a conventional control device for an assembled battery for an electric vehicle of a hybrid type or a pure battery type, an assembled battery is formed by serially connecting a number of battery modules each having one or more battery cells connected in series. The running energy is supplied or recovered by charging and discharging the assembled battery.

When running energy is supplied by discharging the assembled battery, if one of the battery modules constituting the assembled battery is deteriorated or the discharge is completed, even if the other battery modules can be normally discharged, the assembled battery is discharged. Conventionally, it is not preferable to continue discharging as a battery. Conventionally, terminal voltages of all battery modules are monitored, and discharging is stopped when any one of the terminal voltages falls below a predetermined value.

[0004]

However, in the conventional battery control described above, a module voltage detection circuit for detecting a terminal voltage of a battery module based on a voltage detection line extending from the battery module or a potential difference between the voltage detection lines. (For example, disconnection of one of the voltage detection lines) may occur in the detection circuit system. In this case, the degree of deterioration or the remaining capacity of all battery modules cannot be determined.

[0005] Therefore, if any of a large number of detection circuit systems for detecting the terminal voltage of each battery module is abnormal, it is conceivable to set a safety control circuit for stopping discharging of the assembled battery. Even if the detection circuit is abnormal,
The assembled battery itself can be discharged, that is, the electric vehicle can be driven, which causes a problem that the usability is poor. The present invention has been made in view of the above problems, and an object of the present invention is to provide a control device of an assembled battery for an electric vehicle which is excellent in usability without impairing safety.

[0006]

According to the control apparatus for an assembled battery for an electric vehicle of the present invention, the detection circuit system of any one of the battery modules, that is, the voltage detection line or the module voltage detection means becomes abnormal. Also, when this abnormality is detected, the terminal voltage of the battery module detected by the abnormal detection circuit system is estimated based on the stored data stored in advance, so that the state transition of each battery module without any trouble even after the detection circuit system abnormality occurs. Can be estimated and charge / discharge can be continued, so that an easy-to-use control device for an assembled battery for an electric vehicle can be realized without impairing the safety of the battery module.

According to a second aspect of the present invention, the control apparatus for an assembled battery for an electric vehicle according to the first aspect further includes a detection circuit system (minimum value generation) for generating a normal terminal voltage which is the minimum value of the terminal voltage. In the case of an abnormality in a detection circuit system other than the detection circuit system, the discharge is controlled based on the transition of the normal terminal voltage at normal time. That is, in the discharging, the battery module that generates the minimum value among the terminal voltages of the battery modules (also referred to as the minimum value generating battery module) cannot be discharged at the earliest time. The discharge of the assembled battery can be continued without compromising safety only by monitoring the decrease in the terminal voltage of the value generating battery module.

On the other hand, when the minimum value generation detection circuit system becomes abnormal, a terminal voltage detected by a predetermined detection circuit system other than the minimum value generation detection circuit system is detected as a temporary representative terminal voltage. The terminal voltage relationship (storage data) between the temporary representative terminal voltage and the normal representative terminal voltage is stored in advance, and when the minimum value detection circuit system is abnormal, the temporary representative terminal voltage and the terminal voltage relationship are stored. The terminal voltage (minimum terminal voltage) of the minimum value generating battery module is estimated based on the above.

With this configuration, even if an abnormality occurs in the minimum value generation detection circuit system, the minimum terminal voltage of the minimum value generation battery module that is overdischarged (discharge disabled) at the earliest time during discharging can be accurately and simply determined. Therefore, the discharge of the assembled battery can be continued without impairing the safety at all. According to the third aspect of the present invention, in the electric vehicle assembled battery control apparatus according to the second aspect, the terminal voltage of the battery module that generates the second minimum value among the detected terminal voltages is also temporarily represented by the temporary representative terminal. Set as voltage.

With this arrangement, the difference between the terminal voltage of the battery module that generates the second minimum value (the second lowest terminal voltage) and the minimum terminal voltage is small, and the deterioration of both battery modules is reduced. Since the degrees are similar, the characteristics of lowering the terminal voltages during discharge are also similar, so that the estimation accuracy can be improved.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the following examples. However, the present invention is not limited to the configuration of the following embodiment, and it is obvious that the present invention can be configured using a replaceable known circuit.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a voltage detecting device for a battery pack according to the present invention will be described with reference to FIGS. FIG. 1 shows an assembled battery 1
9 is a block diagram showing an assembled battery voltage detecting device for converting each module voltage into a digital signal, and
9, differential voltage detection circuits 201 to 220, A / D conversion circuits 5 to 8, and a photocoupler element 20a are illustrated.
FIG. 2 is a block diagram showing one embodiment of a battery monitoring device using the voltage detecting device of FIG.

1 is a CPU for controlling charging and discharging of a battery, 2 is a selector circuit for distributing a clock signal comprising a demultiplexer (hereinafter also referred to as a clock signal selector circuit),
Reference numeral 3 denotes a selector circuit for distributing a control signal comprising a demultiplexer (hereinafter also referred to as a control signal selector circuit). Reference numeral 4 denotes a selector circuit for selecting a digital signal comprising a multiplexer (hereinafter also referred to as a data selector circuit).
Is an A / D converter circuit, 201 to 220 and 13 are differential voltage detection circuits, 14 is an analog amplifier circuit, 15 is a current sensor, and 101 to 120 are each battery module of the assembled battery 19 (also simply referred to as a module). ). However, in FIG. 2, the battery modules 106 to 120, the differential voltage detection circuits 206 to 220, and the A / D conversion circuits 6 to 8 are not shown.

Each of the battery modules 101 to 120 is composed of one unit cell (battery cell). It is needless to say that the assembled battery 19 may be constructed by cascade-connecting more battery modules. Battery module 101 has the highest module voltage and battery module 120
Has the lowest module voltage. Reference numeral 20 denotes a serial signal line group for connecting each of the selector circuits 2 to 4 and each of the A / D conversion circuits 5 to 10. In this embodiment, each signal line is a CPU.
Each of the photocouplers (for example, 20
a). Each of the A / D conversion circuits 5 to 10 is a switching input type A / D conversion circuit of 5 channel input, and each of the A / D conversion circuits 5 to 10 is synchronously switched by an input switching signal. .

As can be seen from FIG.
Is converted into a signal voltage corresponding to a predetermined reference potential 1 by the differential voltage detection circuit 201 and then A / D converted by the A / D conversion circuit 5. Similarly, module 10
2 is converted into a signal voltage corresponding to a predetermined reference potential 1 by a differential voltage detection circuit 202, and then A / D
A / D conversion is performed by the conversion circuit 5, and the module voltage of the module 103 is converted into a signal voltage corresponding to a predetermined reference potential 1 by the differential voltage detection circuit 203, and then A / D conversion is performed by the A / D conversion circuit 5. The module voltage of the module 104 is converted into a signal voltage corresponding to a predetermined reference potential 1 by the differential voltage detection circuit 203 and then converted by the A / D conversion circuit 5 into an A / D signal.
The D / D conversion is performed, and the module voltage of the module 105 is converted into a signal voltage corresponding to a predetermined reference potential 1 by the differential voltage detection circuit 205, and then A / D converted by the A / D conversion circuit 5.

Similarly, the module voltages of the battery modules 106 to 110 are input to the A / D conversion circuit 6 through the differential voltage detection circuits 206 to 210, and the battery module 1
The module voltages of 11 to 115 are applied to the differential voltage detection circuit 2.
The module voltages of the battery modules 116 to 120 are input to the A / D conversion circuit 7 through 11 to 215, and the A / D conversion circuit 8 is output to the A / D conversion circuit 8 through the differential voltage detection circuits 216 to 220.
Is input to

The total voltage of the assembled battery 19 is converted by the differential voltage detection circuit 13 into a signal voltage with respect to a predetermined common ground potential, and then A / D-converted by the A / D conversion circuit 9. Is subjected to A / D conversion by the A / D conversion circuit 19 through the amplification circuit 14. The outputs of the A / D conversion circuits 5 to 10 are selected in time sequence by the data selector circuit 4 and read into the CPU 1 as a signal SIN. A / D
The conversion circuits 5 to 10 are synchronous operation serial output type A / D conversion circuits. The conversion data, that is, the serial digital signal is output in synchronization with the input clock pulse after the digital signal is determined.

More specifically, the A / D conversion circuit 5 receives an analog input terminal for inputting an analog signal, a data output terminal for outputting a digital signal as a serial signal, and a control command as a serial signal. A control command input terminal, and a clock pulse input terminal to which a clock pulse for synchronization is input, and when a read command is input to the control command input terminal, an edge of the clock pulse input to the clock pulse input terminal The reading of the analog signal is performed in synchronism, and then the input of the next clock pulse outputs an 8-bit serial digital signal.
The other A / D conversion circuits 6 to 10 have the same structure.

A more detailed operation of the battery pack voltage detecting device will be described below. The CPU 1 outputs a clock pulse SCLK and an A / D conversion circuit selection signal SEL to the clock signal selector circuit 2, and outputs a control command signal SOUT such as a read command and an A / D conversion circuit selection signal SEL to the control signal selector circuit 3. Data selector circuit 4
And outputs an A / D conversion circuit selection signal SEL to the data selector circuit 4 to receive a serial digital signal.

(Simultaneous reading) The CPU 1 notifies the clock signal selector circuit 2 and the control signal selector circuit 3 that all of the A / D conversion circuits 5 to 10 are to be selected by the A / D conversion circuit selection signal SEL. Control signal selector circuit 3 converts the read command into A / D conversion circuits 5 to 10
The clock signal selector circuit 2 transmits the clock pulse SCLK to all the A / D conversion circuits 5 to 10, and each of the A / D conversion circuits 5 to 10 transmits the clock pulse SCLK to the edge of the clock pulse input immediately after the input of the read command. The analog signal is read synchronously, converted into an 8-bit digital signal, and held. At this time, the A / D conversion circuit 5
A / D conversion circuit selection signal SEL for selecting all of -10
Is invalidated inside the data selector circuit 4 with respect to the data selector circuit 4.

(Sequential output) Next, the CPU 1 notifies the selector circuits 2 to 4 that the A / D converter circuit 5 is to be selected by the A / D converter circuit selection signal SEL. Clock pulse SCLK is set to A
A / D conversion circuit 5 transmits the serial digital signal to the data selector circuit 4 in synchronism with the edge of the clock pulse SCLK. Since the A / D conversion circuit 5 is selected by the conversion circuit selection signal SEL,
The serial digital signal from the conversion circuit 5 is transmitted to the CPU 1.

Next, the CPU 1 notifies the selector circuits 2 to 4 that the A / D conversion circuit 6 is to be selected by the A / D conversion circuit selection signal SEL, and thereafter performs the same operation as described above to execute the A / D conversion. Converts the serial digital signal of the conversion circuit 6 into a CPU
1, and similarly, the serial digital signal of each of the A / D conversion circuits 8 to 10 is transmitted to the CPU 1. In addition,
The above-described series of operations is performed on the first input channels of the input switching type multi-input A / D conversion circuits 5 to 10. Thereafter, the above-described series of operations is performed on the second to fifth channel input. It is carried out for.

Next, differential voltage detection circuits 201 to 220 for detecting each module voltage of the assembled battery 19 will be described.
This will be described with reference to FIG. In this embodiment, the assembled battery 19 is used.
Are divided into 20 battery modules 101 to 120 that are cascade-connected to each other.
Furthermore, the battery modules 101 to 105 constitute a first voltage detection block, the battery modules 106 to 110 constitute a second voltage detection block, and the battery module 111
115 to 115 constitute a third voltage detection block, and the battery modules 116 to 120 constitute a fourth voltage detection block.

The first voltage detection block has a reference potential 1 as a first reference potential, the second voltage detection block has a reference potential 2 as a second reference potential, and a third voltage detection block. Has a reference potential 3 that is a third reference potential, the fourth voltage detection block has a reference potential 4 that is a fourth reference potential, and the fifth voltage detection block has a reference potential that is a fifth reference potential. It has a potential of 5.

In this embodiment, the reference potential 1 is set to the lower terminal voltage of the battery module 103 (the higher terminal voltage of the battery module 104). 3 from the high potential side in each voltage detection block
The lower terminal voltage of the second battery module (2 from the lower side)
(The higher terminal voltage of the second battery module).

That is, in this embodiment, the reference potential (constant potential applied to one end of the input-side resistor network) of each differential voltage detection circuit in the same voltage detection block is equalized. The detection block has different reference potentials 1 to
4 is applied. Further, each of the reference potentials 1 to 4 is set to an intermediate potential (a value as close as possible to an intermediate value between the highest terminal voltage and the lowest terminal voltage) of each battery module in the voltage detection block. Battery modules as 1-4
Terminal voltage is used.

FIG. 3 is a circuit diagram of the differential voltage detection circuit 201. 2011 is input resistance r1, r2 and feedback resistance r
An operational amplifier having f1 and a battery module 101
The terminal voltage V1 on the high potential side and the reference potential 1 (here, the low-side terminal voltage of the battery module 103 (the battery module 1)
04 (which is set to the high-side terminal voltage of V.04).
-V4) is detected.

Similarly, an operational amplifier 2012 having input resistors r3 and r4 and a feedback resistor rf2 has a difference (V1-V) between the terminal voltage V2 on the low potential side of the battery module 101 and (V1-V2).
4) and the reference potential 1 (here, the battery module 1)
The difference V1-V2 is detected by subtracting the lower terminal voltage of 03 (set to the higher terminal voltage of the battery module 104).

The positive and negative power supply voltages of the operational amplifiers 2011 and 2012 are set to the positive power supply voltage because the potentials at the positive and negative input terminals of the operational amplifier are substantially equal to the virtual ground potential, that is, the reference potential V4 in this embodiment. VH is the reference potential V4
The negative power supply voltage VL is set higher than the reference potential V4 by a predetermined voltage (7.5 V here).
5V) A low voltage may be formed.

The reference potential V1 may be an intermediate potential between the highest potential V1 and the lowest potential V6 of the voltage detection block, and may be formed by using a special voltage generating circuit. Next, a discharge stop control operation of the assembled battery 19, which is a feature of this embodiment, will be described below with reference to a flowchart shown in FIG. It should be noted that the discharge stop control routine of the assembled battery shown in this flowchart is executed by the CPU 1 at a constant cycle during vehicle running together with other various battery control routines.

In FIG. 1, reference numerals 301 to 321 denote voltage detection lines extending from the terminals of the battery modules 101 to 120, and differential amplifiers 201 to 220 are module voltage detection means according to the present invention. Constitutes a detection circuit system abnormality determination unit and a charge / discharge control unit referred to in the present invention. First, each of the battery modules 101 to 12
0 terminal voltage (potential difference) Vi is applied to the differential amplifiers 201 to 22
0 (S100), and these terminal voltages Vi
Of each detection circuit system is determined on the basis of
2). Note that the abnormality of the detection circuit system can be detected by various known methods.In this embodiment, when the terminal voltage drop rate during a predetermined period during discharging at a predetermined current or more is less than a predetermined value, Alternatively, if the value of the terminal voltage deviates from a predetermined range, it is determined that the terminal voltage is abnormal.

In S102, if all the detection circuit systems are normal, the minimum value V among the read terminal voltages Vi
First, the second smallest value V2 is extracted, and these V1 and V2 are extracted.
And the terminal voltage numbers thereof are written in the nonvolatile memory (S104), and the minimum value V1 and the second smallest value V2
Is calculated in the nonvolatile memory (S104), and the process jumps to S114.

On the other hand, if any of the detection circuit systems is abnormal in S102, it is the minimum value V previously stored in S104.
It is determined whether or not the detection circuit system generates 1 (minimum value generation detection circuit system). If not, the process jumps to S114,
If so, the minimum value V1 is calculated using a predetermined calculation formula (S112). An example of the calculation formula will be described below.

Assuming that the previously calculated minimum value is V1 and the second smallest value (also called the second minimum value) is V2, V1 = (V1−V2) + V2 = ΔV + V2. Here, it is assumed that the voltage drop rate of V1 from the previous normal time to the time of this abnormal occurrence is K, which is equal to the voltage drop rate of V2.
The estimated minimum value of this time is V1 ′, and the second minimum value of this time is V
Assuming 2 ′, V1 ′ = KΔV + V2 ′. Further, since K = V2 '/ V2, finally, V1' =. DELTA.V.V2 '/ V2 + V2'.

Next, it is determined whether or not the minimum value V1 or V1 'calculated or estimated in S104 or S112 is in the regulation range, that is, the capacity is considerably reduced, and rapid discharge is not preferable in the battery economy (S114). If so, an alarm is output, unnecessary loads are cut off, and the process proceeds to S118, where large-current discharge is regulated.
Jump to

In S118, it is checked whether or not the minimum value V1 or V1 'has already fallen to a level for immediately prohibiting discharge for battery protection, and if reached, an alarm is output to prohibit discharge (S120). Otherwise, return to the main routine immediately. In the above embodiment,
Although the simple potential difference of the battery module was used as the terminal voltage, the relationship between the terminal voltage and the battery capacity fluctuated depending on the discharge current value, and the open terminal voltage had a more accurate correlation with the battery capacity. The routine of FIG. 4 may be executed by obtaining the open terminal voltage of each battery module by subtracting the battery internal voltage drop represented by the discharge current and the internal resistance from the terminal voltage thus obtained. In this case, the discharge current is preferably detected by a current sensor, and the internal resistance is preferably searched from a map as a function of the terminal voltage and the temperature.

In the above embodiment, when the minimum value V1 is abnormal, the minimum value V1 is estimated based on the second smallest terminal voltage V2. Can also be estimated based on Alternatively, the estimation may be performed based on an average value of a plurality of normal terminal voltages.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an assembled battery voltage detecting device for converting each module voltage of the assembled battery 1 into a digital signal.

FIG. 2 is a block circuit diagram showing one embodiment of a control device for an assembled battery for an electric vehicle using the assembled battery voltage detection device of FIG. 1;

FIG. 3 is a block circuit diagram of the A / D conversion circuit 5 of FIG.

FIG. 4 is a flowchart showing a discharge stop control routine.

[Description of Signs] 19 is an assembled battery, 101 to 120 are battery modules, 2
01 to 220 are differential voltage detection circuits, 301 to 321 are voltage detection lines, and CPU 1 is a detection circuit system abnormality determination means and charge / discharge control means referred to in the present invention.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5G003 BA03 CA11 EA08 EA09 FA06 GC05 5H111 BB02 BB06 CC16 DD11 HA05 HA06

Claims (3)

[Claims] A voltage detection line extending from each terminal of a number of battery modules connected in series to form a battery pack for supplying power to a traveling motor of an electric vehicle, and a calculated potential difference between the voltage detection lines. Control of an assembled battery for an electric vehicle, comprising: module voltage detection means for detecting a terminal voltage of each of the battery modules; and charge / discharge control means for controlling charge / discharge of the battery modules based on the terminal voltage of each of the battery modules. The apparatus, further comprising: a detection circuit system abnormality determination unit that determines abnormality of the detection circuit system including the voltage detection line or the module voltage detection unit based on the terminal voltage, wherein the charge / discharge control unit includes: When it is determined that the battery module is abnormal, the battery module detected by the abnormal detection circuit system based on stored data stored in advance. Terminal voltage estimate, estimated control device of the set electric vehicle battery pack, which comprises controlling the charging and discharging of the battery based on the terminal voltage. 2. The control apparatus for an assembled battery for an electric vehicle according to claim 1, wherein said charge / discharge control means represents a terminal voltage of a battery module which generates a minimum value among the detected terminal voltages in a normal state. A terminal voltage is set, and in the case of an abnormality in the detection circuit system other than the minimum value generation detection circuit system that is the detection circuit system that generates the normal terminal voltage, the discharge is performed based on the transition of the normal representative terminal voltage. Controlling the terminal voltage relationship between an extraordinary representative terminal voltage, which is the terminal voltage detected by the predetermined detection circuit system other than the minimum value generation detection circuit system, and the normal time representative terminal voltage. The battery module that generates the minimum value estimated based on the temporary representative terminal voltage and the terminal voltage relationship in the case of an abnormality in the minimum value generation detection circuit system. Control apparatus for an electric automobile battery pack, characterized in that controlling the discharge based on a terminal voltage of Lumpur. 3. The control device for an assembled battery for an electric vehicle according to claim 2, wherein the charge / discharge control means determines a terminal voltage of the battery module that generates a second minimum value among the detected terminal voltages. A controller for an assembled battery for an electric vehicle, wherein the controller sets the temporary representative terminal voltage.