JPH09129267A - Condition control device for storage battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a condition control system having the capability of making accurate judgement on the residual capacity of a battery system made of many sealed nickel-hydrogen storage batteries for use as a drive power source for a travel body such as an electric vehicle. SOLUTION: This device is formed out of a battery assembly 1, a unit 2 for detecting the conditions of the battery assembly 1, a battery status judgement unit 3, a travel body signal control part 4, a charger 5 to charge the battery assembly 1 controlled with signals from the travel body signal control part 4 and the unit 3, and a display part 6 for showing a battery conditions. Furthermore, the battery status judgement unit 3 has a residual capacity judgement part, and a correcting function regarding a battery characteristic change due to self-discharge, a memory effect, battery storage and a service life.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an assembled battery state management device configured by assembling a plurality of storage batteries such as nickel-hydrogen storage batteries used as a power source for driving a moving body such as an electric vehicle.

[0002]

2. Description of the Related Art Sealed nickel-hydrogen storage batteries and lithium secondary batteries have excellent basic characteristics such as energy density, output characteristics and cycle life characteristics, and have been developed for practical use as power sources for drive motors of mobile vehicles such as electric vehicles. Is progressing. When these storage batteries are used for electric vehicles, an important issue is to estimate the remaining capacity of the storage battery and accurately display the remaining drivable level.

Conventionally, in order to obtain the remaining runnable level information, there is a method of measuring an integrated value of current values input and output from a storage battery or estimating a remaining capacity from a relationship between a discharge voltage and a discharge current. It was Further, in order to improve accuracy, a method of correcting the remaining capacity by predicting the amount of self-discharged electricity discharged when the storage battery is left standing from the standing temperature and time has been adopted. In addition, as for the display of the remaining capacity, there is a method of displaying the remaining capacity as an absolute value, such as a method of displaying 0% at equal intervals with the capacity at the time of completion of charging being 100%.

[0004]

However, in the remaining capacity meter of the storage battery used as the power source for the motor of such a moving body, in addition to self-discharge as a cause of accuracy deterioration, memory effect due to partial charge / discharge, capacity decrease due to long-term storage, cycle There was a decrease in capacity due to life, deterioration of discharge characteristics, etc., and it was a problem to accurately correct errors due to factors.

Also, regarding the remaining capacity display itself, when expressed by the absolute value of the remaining capacity, even if charging cannot be performed with a sufficient amount of charge electricity due to the value of the battery temperature and the charging current, charging is completed.
If the display does not show 00%, or if the remaining capacity after full charge is forcibly set to 100%, the battery capacity at the time of completion of charging is not constant, so how much running level per scale of the remaining capacity meter There was a display problem such as not knowing.

An object of the present invention is to solve the above problems and enable accurate display of the remaining capacity.

[0007]

The present invention is installed in the vicinity of an assembled battery in which a plurality of storage batteries are assembled and detects the battery status information such as the voltage, temperature and pressure of the storage batteries, ambient temperature, and charging / discharging current. , An analog-digital conversion function for converting the obtained detection value from an analog value to a digital value, a detection unit for sequentially outputting the digital value in a serial system, and a mobile object signal control unit for controlling various kinds of information of the mobile object. An arithmetic unit that performs arithmetic processing based on the information from the detection unit and the mobile signal control unit; a remaining capacity determination signal unit that sends a remaining capacity determination signal to the display unit; and a remaining capacity determination unit from the battery state determination unit. And a display unit that displays the remaining capacity of the battery, which is controlled by a signal.

The remaining capacity determining section has a function of integrating the charging / discharging currents sent from the detecting section, a function of estimating the remaining capacity from the battery voltage and the discharge voltage, and a self-discharged electric quantity from the battery storage period and temperature. A function to predict, a function to judge the current integration result to be invalid when the self-discharged electricity quantity is predicted to be larger than the initially set value, an integrated electricity quantity and battery voltage and discharge voltage based on the history of charge / discharge electricity quantity. A function of correcting the obtained remaining capacity, a function of measuring a period during which the battery is not charged / discharged, a function of correcting the remaining capacity based on the period, a function of outputting the remaining capacity to the display unit as 100% after full charging, Remaining capacity is 50 ~ standard battery capacity
In the case of 20%, the value is displayed according to the value.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In this apparatus, the detection unit includes a battery voltage, temperature, charge current, discharge current, battery internal pressure,
Also, the battery state information such as the environmental temperature is detected and the obtained information is sent to the battery state determination unit. The remaining capacity determination unit is
Charge / discharge current integration function, function to calculate remaining capacity from battery voltage and discharge current, function to prevent discharge voltage from decreasing due to memory effect when partial charge / discharge is repeated, function to estimate remaining capacity estimation accuracy, self-discharge A function that predicts the amount of electricity, a function that discards the current integration result when the amount of self-discharge electricity is large, a function that corrects the result of obtaining the remaining capacity from the battery voltage and discharge current when the battery is left for a long time, charge / discharge history, A highly accurate remaining capacity display is achieved by the function of correcting the influence of deterioration of life, 100% after the completion of charging, and the function of displaying according to the battery standard capacity at the end of discharging.

[0010]

1 is a block diagram showing an embodiment of a storage battery state management apparatus of the present invention. The apparatus shown in FIG. 1 is all mounted on a moving body such as an electric vehicle. In FIG. 1, the battery pack 1 is connected to a detection unit 2 that detects battery state information such as a battery voltage V, a battery temperature TTB, a battery pressure P, and an ambient temperature TE.

The battery state determining unit 3 includes the detecting unit 2 and a moving body signal control for controlling the discharging current, the charging current of the battery, the regenerative current to the battery generated when the moving body is braked, and various information of the moving body. Charger 5 that supplies a charging current to the battery pack 1 using the section 4 and an AC power supply as an input, and is controlled by a charging control signal from the battery state determination unit 3.
And the display unit 6 for displaying the battery state by the signal from the battery state determination unit 3 is connected.

The charger 5 is connected to the assembled battery 1 and is controlled by a charging control signal from the battery state discrimination unit 3 to supply a charging current to the assembled battery 1 during charging. Further, the battery pack 1 is cooled by the cooling air sent from the air blower 7 in order to make its temperature uniform. The assembled battery 1 is connected to a load 8 such as a motor and supplies electric power thereto.

FIG. 2 is a diagram showing the configuration of the battery state discrimination unit 3 in this embodiment. The battery state determination unit 3 is a central processing unit (CPU)
101, the detection unit 2 includes a CPU 102, the mobile body signal control unit 4 includes a CPU 103, and the charger 5 includes a CPU 104.

The battery state determination unit 3 is the detection unit 2
And a calculation unit 110 that performs calculation processing based on information from the mobile unit signal control unit 4, a charge control signal unit 111 that sends a charge control signal to the charger 5, and a remaining capacity that sends a remaining capacity determination signal to the display unit 6. It has a judgment signal unit 112, a life judgment signal unit 113 for sending a life judgment signal to the display unit 6, and a mobile unit control signal unit 114 for sending a mobile unit control signal to the mobile unit signal control unit 4.

Further, the battery state determination unit 3, the detection unit 2, the mobile unit signal control unit 4, the charger 5 and the display unit 6 are provided.
Are connected by signal line groups such as serial signals, digital signals, analog signals, etc., to exchange information with each other,
Control can be performed.

FIG. 3 is a diagram showing the structure of the assembled battery 1. The assembled battery 1 is composed of 10 pieces of N having a nominal voltage of 1.2 V explained in FIG.
It is configured by connecting 24 module batteries, which are cells 401 to 410 of an i / MH storage battery, connected in series as 201 to 224, all of which are housed and fixed in a battery stand 105.

Therefore, the assembled battery 1 is constructed by connecting 240 cells in series explained in FIG. 5, and the total battery voltage of the assembled battery is 288V. The battery pack 1 is mounted under the floor of a moving body or in the rear of a seat, and is used as a power source for a load such as a motor.

FIG. 4 is a diagram showing the structure of the module battery. The module battery is configured by connecting 10 single cells in series, is fixed in a module frame 400 made of metal, and 10 cells are mechanically integrated, and are easily handled as one assembled battery. It has a structure that allows it.

In this embodiment, ten cells are connected in series to form a module battery, so that the battery voltage of the module battery is 12V.

It should be noted that in consideration of the space for arranging the batteries, etc., 9
The assembled battery 1 can also be configured by combining module batteries configured with different numbers of cells such as 10, 10 and 11 cells.

FIG. 5 is a diagram showing the cell structure of the sealed nickel-metal hydride storage battery of this embodiment. An electrode group 22 composed of a positive electrode plate, a negative electrode plate and a separator is housed in a battery case 21, the positive electrode plate is connected to a positive electrode terminal 23, and the negative electrode plate is connected to a negative electrode terminal 24.

The lid 26 of the battery case 21 has terminals 23, 2
In addition to 4, a safety valve 25 that opens to release gas when the pressure exceeds a certain pressure is provided.

In the present invention, the voltage is 1.2 V and the nominal capacity is 100
A cell of Ah was prepared and tested.

The above is the storage battery state management system used in this embodiment. Next, the function of the remaining capacity determination unit of the battery state determination unit will be described for each example.

First, the conventional example A is shown. A holds a dischargeable capacity value based on the battery temperature at the time of charging, which will be hereinafter referred to as a remaining capacity, as a remaining capacity value according to the charge completion signal of the charge control signal unit. After that, when the moving body starts traveling, the discharged electricity amount is obtained from the inspection unit and subtracted from the dischargeable capacity value. Further, the amount of electricity to be regeneratively charged is added after being multiplied by the charging efficiency. When the vehicle is stopped for a long time or is left for a long time while the vehicle is running, the self-discharged electricity amount is subtracted from the remaining capacity at regular intervals according to the rest period, the battery temperature during the stop, and the remaining capacity of the battery. The obtained remaining capacity information is sent to the battery remaining capacity display section.

Next, a conventional example B having means for estimating the remaining capacity from the voltage of the running battery, the battery temperature, and the discharge current.
Is shown.

The battery voltage, battery temperature and discharge current are measured by the inspection unit. By applying these data to the following relational expressions, the circuit voltage of the battery in the standard state is obtained. The remaining capacity is estimated from the circuit voltage thus obtained.

Open circuit voltage in standard state = f (measured voltage + battery internal resistance × polarization component, battery temperature) The load current during running fluctuates drastically. for that reason,
Battery voltage is also greatly affected by load current. When constant current discharge is performed, it is relatively easy to obtain the remaining capacity from the discharge voltage. Therefore, it is necessary to estimate the battery voltage at no load or at a constant load in order to eliminate the influence of fluctuating load. The effect of the change in discharge current on the battery voltage is divided into a portion due to internal resistance and a portion due to polarization, and is measured in advance, and correction is performed based on that. Further, the voltage change due to the battery temperature is also corrected based on the relationship with the temperature measured in advance, and for example, the voltage at the battery temperature of 25 ° C. and no load (hereinafter referred to as the standard state circuit voltage) is obtained.

Remaining capacity = g (circuit voltage in standard state) Further, the remaining capacity is estimated from the circuit voltage in standard state which is obtained in advance.

The remaining capacity of the battery is calculated based on the above two equations. The internal resistance of the battery is obtained from the instantaneous change amount of the discharge current and the change of the battery voltage. The polarization component is the average discharge current,
It is experimentally obtained in advance based on the battery voltage.

In actual measurement, the sampling error is large because the discharge load fluctuation is large. In order to prevent this, it is important to measure data with high simultaneity of discharge current and discharge voltage. In this embodiment, a low-pass filter of several Hz is provided at the input portion of the battery voltage and the discharge current, and the A / D
A converter is installed independently, and A / D conversion is performed simultaneously by a common conversion request signal to measure data with high simultaneity.

Further, in order to improve the accuracy of the measurement, the measurement was carried out several times per minute, and the moving average was calculated to obtain the residual capacity.

Next, Example C according to the present invention will be shown. C is
It has both the functions of A and B. The remaining capacity value obtained by the two functions is selected and displayed according to the amount of self-discharged electricity when the battery is left unattended. As the estimated value of the self-discharged electricity amount which is the basis for selection, the value used for the correction of the self-discharged electricity amount in Example A is used. When the amount of self-discharge electricity exceeds 20 Ah, the method of estimating the remaining capacity from the battery voltage, battery temperature, and current is given priority.

The embodiment D is a system in which the function of correcting the deterioration of the estimation accuracy of the remaining capacity when the discharge voltage is lowered by the memory effect is added to C. The decrease in discharge voltage occurs due to the memory effect when the nickel-hydrogen storage battery is repeatedly charged and discharged incompletely. As for the correction method, for example, when discharge 50% ⇔ full charge is repeated, a potential decrease on the undischarged side occurs near the end of discharge as shown in the table below, so a correction value larger than the discharge portion is set. When the incomplete discharge is repeated for several cycles, the correction value of the area corresponding to the undischarged portion is similarly added. Then, in the estimation of the remaining capacity when the complete discharge is performed, the obtained standard state open circuit voltage is compared with the standard state open circuit voltage-correction value in the table, and the remaining capacity at the coincidence is read.

If there is no matching value, it is calculated by interpolation.
When the complete discharge is performed, the memory effect is reduced or eliminated, so the correction value is reset to 0.00 or a value close thereto.

[0036]

[Table 1]

In Example E, in addition to D, a function of correcting a decrease in charging voltage due to leaving the battery unattended and a function of correcting a decrease in accuracy of a method of estimating the remaining capacity from the battery voltage, the battery temperature, and the discharge current were added. Is the way.

As the correction value, the battery is previously set under each temperature condition −20.
The discharge voltage reduction amount is obtained by storing at 7, 0, 20 and 45 ° C for 7, 14, 21 days.

[0039]

[Table 2]

In the same manner as in Example D, when the nickel-hydrogen storage battery was stored for a long time without being charged and discharged, the discharge voltage of the battery was lowered due to the change in the scientific state of the battery active material. This is a product to which a function of correcting the deterioration of the accuracy of the method of estimating the remaining capacity from the battery temperature and the discharge current is added. The correction method is, for example, 2 at 45 ° C.
After storage for 1 day, the correction value is added to the measured value of the standard state open circuit voltage to estimate the remaining capacity. Since this voltage drop is resolved by charging / discharging for 3 to 5 cycles, the correction value is gradually reduced by repeating charging / discharging.

In Example F, a function of correcting the decrease in charging voltage due to the charging / discharging cycle of the battery and correcting the accuracy deterioration of the method of estimating the remaining capacity from the battery discharging voltage, battery temperature, and discharging current was added. It is a thing.

Specifically, the voltage drop due to the charge / discharge cycle of the battery is measured in advance. In order to measure the basic data of this example, a battery charge / discharge test was separately conducted in the following manner. Regarding the battery after the life test,
A correction value was obtained by measuring the relationship between the remaining capacity and the open circuit voltage in the standard state. As a method of incorporating the correction table into the example F, a method of obtaining a correction value when one cycle of charging and discharging was performed at each temperature and adding the correction value for each cycle was adopted.

[0043]

[Table 3]

[0044]

[Table 4]

After charging / discharging according to the following evaluation patterns for Examples A to F, a separately provided discharge coulometer was connected to perform a complete discharge to compare the deviation of the indicated values.

The discharge electricity meter has a sampling interval of 10 kHz.
A z current with an accuracy of ± 0.1 A was used.

[0047]

[Table 5]

The results evaluated under the above evaluation conditions are summarized in the table below. Shown in the table are the deviations from the electricity meter used for comparison.

[0049]

[Table 6]

The conventional example A shows high accuracy when the influence of self-discharge is small, but the conventional example B shows that the amount of self-discharge electricity is large.
Method has high accuracy. Example C of the present invention, which is switched and displayed according to the amount of self-discharged electricity, shows excellent values for both. Further, the effects of partial charge and discharge, the effects of leaving the battery on, and the effects of the life of the battery cannot be secured with sufficient accuracy unless they are corrected by the methods of Examples D, E, and F, respectively.

As described above, by combining the respective corrections according to the present invention, it becomes possible to estimate the remaining capacity with higher accuracy.

Next, an example of displaying the remaining capacity will be described. Example G and conventional examples H and I are shown in FIGS. 6, 7 and 8, respectively.

In this embodiment G, the display of the remaining capacity at the time of completion of charging is not affected by the charging temperature or the charging current and is always 100%.
Is displayed. This is a guide for the user to confirm that the charging has been completed successfully. In the latter half of the discharge, the remaining capacity display 1Ah is always displayed so as to correspond to 1%.
As a result, it is possible to accurately grasp how much the vehicle can travel with the indicated value of the meter. When charging is completed and the remaining capacity is 50 Ah
Points are interpolated by a straight line as shown.

In Conventional Example H, the remaining capacity at the completion of charging is 1
Since it is set to 00%, the display when charging is completed is always 100%
Is shown. However, since 1% at the end of discharge has a proportional relationship with the remaining capacity at the time of completion of charging, there is a problem that an accurate travelable distance cannot be grasped from the remaining capacity display at the end of discharging. In the case of charging at 45 ° C. shown in FIG. 7, 1% has a value of 0.9 Ah.

In the conventional example I, an amount corresponding to the remaining capacity is displayed at the time of completion of charging. Therefore, 1 of the remaining capacity is displayed.
% Corresponds to 1 Ah, and it is possible to accurately understand how far the vehicle can be run from the display. However, since the remaining capacity at the time of completion of charging changes depending on the charging current and the temperature, the display at the time of completion of charging has various values. FIG. 8 shows the result of charging at 45 ° C., but the display shows 90%. As described above, it is difficult for the user to confirm that charging is completed smoothly, which is a problem.

As described above, according to the present embodiment, it is possible to provide a display method by which the user can confirm that the charging has been smoothly finished and can accurately grasp the remaining capacity at the end of discharge.

[0057]

According to the present invention, an assembled battery in which a large number of storage batteries used as a power source for driving a moving body are assembled, a detection unit, a charge control signal section, and a remaining capacity determination signal section for sending a remaining capacity determination signal to the display. A system consisting of a battery status determination unit, a charger, and a battery remaining capacity display section that displays the information sent from the remaining capacity determination signal section, and is less susceptible to self-discharge, battery storage, memory effect, and life deterioration It becomes possible to judge the remaining capacity, show 100% of the remaining capacity when charging is completed normally, and show an indicated value that always matches the remaining capacity at the end of discharge.

As a result, the remaining capacity can be accurately confirmed and the moving body such as an electric vehicle can be operated completely.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a storage battery state management system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a battery state determination unit and a connection with related devices according to an embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of an assembled battery of the present invention.

FIG. 4 is a diagram showing a configuration of a module battery.

FIG. 5 is a diagram showing the structure of a sealed nickel-hydrogen storage battery that is a cell.

FIG. 6 is a diagram showing a method of displaying the remaining capacity according to the present invention.

FIG. 7 is a diagram showing a method of displaying a remaining capacity according to a conventional example.

FIG. 8 is a diagram showing a method of displaying a remaining capacity according to a conventional example.

[Explanation of symbols]

 1 assembled battery 2 detection unit 3 battery state determination unit 4 mobile unit signal control unit 5 charger 6 display unit 7 blower unit

Front page continuation (72) Inventor Noboru Ito 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (5)

[Claims] 1. An assembled battery connected to a plurality of storage batteries used as a power source for driving a mobile body, a detection unit for detecting status information of the storage batteries, and an arithmetic unit for performing arithmetic processing based on the information from the detection unit. , A battery state determination unit having a remaining capacity determination signal unit for sending a remaining capacity determination signal to the display, a charger for charging the assembled battery controlled by a charging control signal from the battery state determination unit, and a remaining capacity determination It consists of a battery remaining capacity display section that displays the information sent from the signal section.The remaining capacity is calculated by the means for integrating the charging / discharging current of the battery with respect to time and the self-discharged electricity amount calculated from the battery leaving time and the leaving temperature. Compensation means and means for calculating the remaining capacity from the discharge voltage, battery temperature, and discharge current of the storage battery, are used to supplement the remaining capacity by the self-discharged electricity amount. When the value exceeds the specified value, the storage battery using means for estimating the remaining capacity from the discharge voltage, battery temperature and discharge current of the storage battery, and means for integrating the charge / discharge current with respect to time except the above State management device. 2. A battery having a means for recording the amount of charge and discharge electricity, and using the remaining capacity obtained by integrating the charge and discharge current of the battery with respect to time based on the recording of the amount of charge and discharge electricity. The battery state management device according to claim 1, wherein the remaining capacity calculated from the discharge voltage, the battery temperature, and the discharge current is corrected. 3. The battery according to claim 1, further comprising means for storing a time when the battery is not charged and discharged, and correcting the remaining capacity calculated from the discharge voltage, the battery temperature and the discharge current of the battery according to the time when the battery is not charged and discharged. Battery condition management device. 4. A means for storing the number of times the battery has been charged and discharged or the amount of electricity, which is calculated from the discharge voltage, battery temperature and discharge current of the battery according to the number of charge and discharge cycles or the amount of charge and discharge electricity. The battery state management device according to claim 1, wherein the state of charge is corrected. 5. The remaining capacity display section displays a value when the completion of charging is 100%, and when 50% or less of the capacity of the battery pack is displayed, it is displayed as a ratio to the capacity, and the spaces are interpolated and output. A storage battery state management system according to claim 1.