JPH05172915A - Device for displaying state of battery - Google Patents

Abstract

PURPOSE:To precisely recognize the state of a battery. CONSTITUTION:The actual capacity (residual capacity) of a battery 2 is successively calculated in such a way that the initial capacity of the battery 2 is found based on the capacity of the battery 2 calculated from the terminal voltage of the battery 2 when the battery 2 discharges at a prescribed current level, and the charged and discharged currents of the battery 2 after the initial capacity is found are integrated. The recargeable capacity (full charging capacity) of the battery 2 is calculated on the basis of the difference between the initial capacity and the value calculated by integrating the charged and discharged currents until the point of time immediately before finding the initial capacity. Then both of the full charging capacity and residual capacity of the battery 2 are indicated by means of pointers 200 and 300.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery status display device, and more particularly, to a battery status display device for displaying a chargeable capacity and an actual battery capacity which are lowered due to deterioration of the battery or the like.

[0002]

2. Description of the Related Art Conventionally, for example, a battery for a vehicle is generally not displayed with its capacity, and the life of the battery is deteriorated and the battery is discharged due to discharge. ． ． In the current situation, the user has empirically determined from the operating state of the electric load. Also, even in an electric vehicle that uses a battery as a drive source for the vehicle, only the battery voltage is displayed, and this voltage allows the user to empirically determine the remaining capacity of the battery (how long it can operate in the future, etc.). It is the current situation.

[0003]

However, the capacity of the battery actually decreases not only due to discharge but also due to deterioration. In other words, the former is the case where the charge is insufficient compared to the chargeable capacity of the battery, and the latter is the chargeable capacity that has decreased due to deterioration of the battery, so the actual charge is This is the case when the capacity is not exceeded.

When the user judges the state of the battery, it is difficult to judge whether the decrease in the capacity of the battery is due to the discharge or the deterioration as described above. ..

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it provides a full charge capacity value when a battery is fully charged (when it is charged to a chargeable capacity) and an actual battery. The present invention provides a battery status display device configured to also display the capacity value of the battery (hereinafter, referred to as “remaining capacity value”).

[0006]

According to the above configuration, the user can properly recognize the remaining capacity of the battery and also the deterioration state of the battery, so that the user can appropriately take measures for the battery. You can In other words, the battery may be replaced even if it has decreased due to discharge, or the battery may be charged to recover its capacity even if it has deteriorated due to deterioration, resulting in overcharging and deterioration of the battery. It can be prevented from being promoted.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a vehicle will be described below with reference to the drawings. FIG. 1 shows a display unit of a vehicle battery capacity display device. A scale 100 indicates the rated capacity value of the battery (initial full-charge capacity value), and the display position is fixed. Reference numeral 200 is a guideline indicating the full charge capacity value when the battery is in use. Since the full charge capacity matches the rated capacity value when the battery is new, the scale 100 is indicated (depending on the setting method of the rated capacity value, Specify a value greater than 100 on the scale). When the battery deteriorates with use of the battery, the capacity of the pointer 200 does not increase to the rated capacity even when the battery is fully charged, so that the pointer 200 cannot reach the scale 100.

Reference numeral 300 is a guideline indicating the value of the remaining capacity when the battery is in use. Since the battery can be charged to the rated capacity when the battery is new, the remaining capacity is equal to the rated capacity. In this state, the pointer 300 indicates the scale of the rated capacity value like the pointer 200. And
When the battery discharges and the capacity decreases during driving, the pointer 300
Moves to the left in the drawing, and the area a increases. That is, the pointer 300 swings to the left or right each time as the battery is charged or discharged.

On the other hand, the pointer 200 indicates the full charge capacity value, and gradually fluctuates over a long period of time (as the battery deteriorates). A battery state display unit 400 is divided into a good state c, a bad state d, and a dangerous state e in which the battery may run out. If this area is changed according to the environment in which the vehicle is used (for example, if the ambient temperature becomes low, the good area is reduced, the defective area, the dangerous area is enlarged, etc.), the more accurate the display becomes.

By providing the battery capacity display section as described above, the user can be informed of the full charge capacity and the remaining capacity of the battery, and the user can accurately grasp the deterioration state and charge / discharge state of the battery. Therefore, the vehicle trouble caused by the battery can be prevented, and the user can feel secure.

Hereinafter, (1) battery capacity detection, (2) battery status display, and (3) power generation control will be described in detail. (1) Battery capacity detection FIG. 2 shows the electric power system of the vehicle. As is well known, by turning on the starter switch 1 and supplying the electric power from the battery 2 to the starter 3, the starter 3 rotates and the engine 4 starts. The generator 5 is driven by the engine 4.
Driven via a belt and a pulley (not shown), the battery 2 is charged and electric power is supplied to an electric load 6 such as a lamp, a blower motor, a defogger and the like. The current sensor 7 detects a discharging current from the battery 2 and a charging current to the battery 2. The temperature sensor 8 detects the temperature of the battery 2. The battery capacity detection circuit 9 inputs signals relating to the current and temperature from the current sensor 7 and the temperature sensor 8 and also inputs the terminal voltage of the battery 2, and based on these signals, the full charge capacity of the battery 2. And calculate the remaining capacity. The data obtained by the calculation is sent to the display device 10 having the above-described display portion, and the display device 10 displays the data according to the data to make the user recognize the state of the battery 2. The data of the battery capacity detection circuit 9 is also sent to the power generation control circuit 11. The power generation control circuit 11 controls the power generation of the generator 5 and the idle rotation speed of the engine 4 based on this data, the terminal voltage of the battery 2, and the rotation speed of the engine 4.

Next, the battery capacity detection circuit 9 will be described in detail. FIG. 3 is a block diagram showing processing functions in the battery capacity detection circuit 9, and FIG. 4 is a battery capacity detection circuit 9
It is a flow chart which shows control in.

In the flowchart shown in FIG. 4, when a key switch (not shown) is turned on, the process is started (step 10). First, the battery 2 when starting the engine
The discharge characteristics of are measured (step 20). Figure 5
It will be described according to the flowchart of In step 202, the current signal I _B1 from the current sensor 7 is supplied to the current detector 90.
Read from 6. It is determined that the starter 3 is started when the current signal I _B1 shows the discharge current of 100A. Step 204 has a timer function of 50 ms. This is because immediately after the starter 3 is started, a large current rapidly flows and noise is generated, so that it is not affected by this noise.

After the influence of noise is eliminated in step 204, the current signal I _B1 (discharge current) from the current sensor 7 is read in step 205. Then, the current signal I _B1 which is read, as long as it exhibits a discharge current of 60～250A, it is determined that the starter 3 is operating (step 206). When it is determined that the starter 3 is operating, the voltage V _{B1 of the} battery 2 is read from the voltage detection unit 907 (step 207). Here, the above range of the discharge current is set because it is determined that a current of 60 A to 250 A flows through the starter 3 when the starter 3 is operating and the engine 4 has not started yet. It is not necessary to limit the range.

Next, the current signal I _B1 for the battery 2
The voltage V _B1 and the time t are stored in the discharge characteristic calculation unit 910 (first battery capacity detecting means) (step 208).
Step 209 is set for 3 s after starting the starter 3 (usually, it is set a little larger in consideration that 1 s is not required from the start of the starter to the start of the engine), and the operations of the steps 205 to 209 are performed. That is, the timer function is provided so that the current signal I _B1 and the voltage V _B1 during the operation of the starter 3 are read and stored at 25 ms intervals.
That is, the discharge characteristic calculation unit 910 stores the current signal I _B1 and the voltage V _B1 corresponding to the time t. It should be noted that the discharge characteristic calculation unit 910 always stores ten new data.
Then, when it is determined in step 206 that the discharge current has become 60 A or less and the engine 2 has started, the data is not read thereafter, and 3 seconds after the starter 3 starts, the process proceeds to step 210 in step 209.

At step 210, at step 208
From the stored data, the current signal of battery 2 (discharge current)
I_B1Maximum value of_BMAXAnd this maximum value I_BMAXRead at the same time
Embedded voltage V_B1, And time t are V_IMAX, And t
_IMAXThen, in the next step 211, this time reversely
Current signal (discharge current) I_B1The minimum value of_BMINAnd this minimum
Value I_BMINVoltage V read at the same time_B1, And time t
Each V_IMIN, And t _IMINCalculate as And sideways
The axis is the current signal I_B1, Vertical axis is voltage V_B1Set as
The maximum value I of the current signal_BMAXAnd the voltage V at that time_IMAXTo
Coordinates determined by the above, and the minimum value I of the current signal_BMINToso
Voltage V_IMINThe coordinates determined by
And draw a characteristic diagram connecting them with straight lines.

Next, from this characteristic diagram, the voltage V _B1 when the current signal I _B1 indicates the discharge current 150 A is calculated as the first capacitance detection voltage V _Bd1 . Further, the time t from the start of the starter start until the detection of the voltage V _Bd1 is the time t in step 210.
_Then , the average of t _IMAX and t _IMIN calculated in step 211 is taken as the capacitance detection time t _d . However,
The value of the discharge current for determining the first capacitance detection voltage V _Bd1 need not be limited to 150 A in particular.

The first capacitance detection voltage V thus detected
_Bd1 is corrected as shown in FIG. 6 for the following reason.
That is, the battery voltage when the battery 2 is discharged decreases with time. On the other hand, the start time of starting the engine 2 by driving the starter 3 is usually within 1 second, but it varies depending on the environmental conditions at that time. In order to correct the error due to the variation in the discharging time, the voltage is corrected to 5 seconds after that which is generally used in the discharging characteristics of the battery (step 302). That is, the relationship between the discharge time and the voltage when the battery 2 is discharged at 150 A is obtained in advance, and this characteristic and the first capacitance detection voltage V _Bd1 determined by the discharge current when the starter is driven, and the capacitance thereof using the detection time t _d, of voltage and 5 seconds after the voltage at the detection time t _d deviation ΔV
The by correcting the capacity detection voltage V _Bd1, the battery 2 can be obtained as 5 th second voltage when discharged at 150A, to do this with the second capacity detection voltage V _Bd2.

Further, since the battery voltage has a temperature characteristic, the temperature signal T _B detected by the temperature sensor 8
Is input from the battery temperature detection unit 908 (step 30
3), according to the temperature signal T _B , the second capacitance detection voltage V
_Bd2 is corrected (step 304). With this correction, a more accurate voltage of the battery 2 can be obtained.
Of the capacitance detection voltage V _Bd3 .

Next, the first battery capacity VI ₁ when the starter is driven is determined from the third capacity detection voltage V _Bd3 , which will be described below. The solid line in FIG. 7 is a characteristic diagram showing the relationship between the battery voltage and the battery capacity in the case where the battery 2 is discharged at a predetermined current for a predetermined time and there is no stratification of the battery liquid specific gravity or the occurrence of polarization immediately after charging. As shown in the figure, when the battery capacity is small, the battery voltage becomes small. Then, this characteristic is stored in the discharge characteristic calculation unit 910. This characteristic diagram, using the third capacity detection voltage V _Bd3 determined at step 305 as described above, the capacity of the battery 2 when the starter 3 driven (hereinafter,
VI ₁ (referred to as “first battery capacity”) is determined (step 305).

If the capacity of the battery 2 is unknown because the previous run was the first run, or the battery 2 was replaced before the previous run but was not the first run, the battery capacity monitor unit 911 causes the battery capacity monitor unit 911 to execute the first run. The battery capacity VI ₁ is defined as the remaining capacity at the beginning of running (initial capacity VI ₀ ), and the preset rated capacity value of the battery 2 is defined as the full charge capacity (initial capacity setting).

The current integration unit 909 integrates the current signals (charging and discharging current) of the battery 2 after the engine 4 is started and detected by the current sensor 7 and read by the battery current detection unit 906, and the battery capacity monitoring unit 909. 911 is
The second battery capacity VI ₂ during traveling, that is, the remaining capacity during traveling is calculated by adding the integrated value of the charging / discharging current to the remaining capacity at the beginning of traveling. Then, the battery capacity monitor unit 911 stores the maximum value of the second battery capacity VI ₂ during traveling as VI _2MAX and the last value as the third battery capacity VI ₃ . In the present running, it will be described below that the maximum value VI _{2MAX of} the third battery capacity VI ₃ and the second battery capacity VI ₂ is stored in the battery capacity monitor unit 911. Returning to FIG. 4, when the first battery capacity VI ₁ is calculated in step 30, the third battery capacity VI ₃ is read (step 40).
The first battery capacity VI ₁ calculated by the battery capacity monitor unit 911 when the starter 3 is driven and the third
Battery capacity VI ₃ (that is, the first battery capacity V
The second battery capacity VI ₂ ) immediately before the detection of I ₁ is compared and the smaller value is regarded as the true value, and the initial capacity VI ₀
Set as. If the normal battery 2 is in good condition, the first and third battery capacities VI ₁ and VI ₃ are
Since the values are substantially equal to each other, either of the first and third battery capacities VI ₁ and VI ₃ may be adopted. However, since the first and third battery capacities VI ₁ and VI ₃ are not always equal, the smaller one is adopted.

First, the first battery capacity VI ₁
The case where the battery capacity VI _{3 is} increased by a predetermined value will be described. In the battery 2, when the phenomenon that the concentration of the battery liquid increases near the electrodes (hereinafter, referred to as polarization) immediately after the stratification of the battery liquid specific gravity or immediately after charging, the characteristic of the voltage with respect to the capacity is the broken line in FIG. 7. become that way. That is, when stratification or polarization occurs, the battery voltage becomes higher than the normal value. Therefore, when stratification or polarization occurs during the detection of the first battery capacity, the capacity detection voltage is detected to be higher than the normal value, and the first battery capacity VI ₁ is greater than the true capacity and the third battery capacity VI ₃ . growing. Therefore, it is determined that the third battery capacity VI ₃ is close to the true capacity, and is set as the initial capacity.

On the contrary, the third battery capacity VI ₃ is equal to the first
A case where the battery capacity VI _{1 is} larger by a predetermined value will be described. This is the battery 1 by the running generator 5.
This is the case where the gassing phenomenon occurs due to the electrolysis of water in the battery liquid due to the fact that the battery 1 is charged even though the battery 1 is close to the fully charged state due to the charging. When gassing occurs, the integrated value of the battery charging / discharging current, which is the basis of detection of the second battery capacity VI ₂ , is a value integrated including the charging current used for gassing,
The second battery capacity VI ₂ is detected to be larger than the true capacity. For this reason, the second battery capacity V that is greatly required is
The third battery capacity VI _3, which is the final value of I ₂ , becomes larger than the true capacity and the first battery capacity VI ₁ . Therefore, it is determined that the first battery capacity VI ₁ is close to the true capacity, and is set as the initial capacity.

In contrast to the above stratification, gassing causes bubbles in the electrodes, and the battery liquid is agitated by the bubbles, so stratification and gassing are unlikely to occur at the same time. That is, the first and third battery capacities VI ₁ ,
Since both VI ₃ do not increase, it is possible to know the capacitance closer to the true value by adopting the smaller one as described above.

(2) Battery Status Display Next, the calculation and display of the full charge capacity (step 60) will be described with reference to FIG. First, it is confirmed whether the full charge capacity data is stored (step 601). If there is no data, it is determined that the battery 1 has been replaced, and the rated capacity value of the battery 1 is adopted as the full charge capacity (step 602). When it is confirmed in step 601 that the full charge capacity data is stored, the first battery capacity VI ₁ and the third battery capacity VI ₃ are compared (step 603). If the first battery capacity VI ₁ is large, the full charge capacity VI _M adopted during the previous running is also adopted this time (step 604). On the other hand, if the third battery capacity VI ₃ is large, the maximum value VI _2MAX of the second battery capacity VI ₂ during the previous travel and the first battery capacity VI
_{Using 1} and the third battery capacity VI ₃ , the full charge capacity VI _M is calculated by the following formula. In addition, this full charge capacity VI
Regarding the calculation of _M, the applicant of the present invention has already shown in the prior application (Japanese Patent Application No. 3-139270).

[0027]

## EQU1 ## VI _M1 = [VI _2MAX − (VI ₃ −VI ₁ )] / k

[0028]

[Equation 2] VI _M = (VI _M1 + VI _M2 + VI _M3 + ... +
VI _Mn ) / n That is, as shown in Formula 1, first, the data VI _M1 at the time of the current traveling is calculated based on each data at the time of the previous traveling,
As shown in Formula 2, this data and past data V
I _M2 , VI _M3 ,. ． The full charge capacity VI _M is calculated from the average of the above.

The constant k is approximately 100% when the charging efficiency of the battery is 80% or less of the battery capacity as shown in FIG. 8, and when charging is performed with the battery capacity of 80% or more, which reduces the charging efficiency, the constant k of FIG. Thus, from the first battery capacity VI ₁ to the third
Since that will increase the battery capacity VI _3, k = _0. Full charge capacity of about 8 can be calculated. As shown in FIGS. 8 and 9, when the battery deteriorates, the charging efficiency decreases from the capacity lower than the rated capacity, but when the individual full charge capacity value is taken as 100%, the battery capacity decreases from about 80%. = _0. well at about 8, or may be gradually reduced k in accordance with the deterioration of the battery.

Further, VI _M2 and VI _M3 are the data at the time of the previous run and the data at the time of the previous run, that is, from the new data, as VI _M1 , VI _M2 , VI _M3 , --VI-- _Mn , the battery capacity monitor section. It is stored in 911. Since the deterioration of the battery 2 gradually progresses over a long period, n is 5 to 10
The degree is enough. The full charge capacity VI _M obtained above is displayed on the display 10
Display at.

On the other hand, the calculation and display of the remaining capacity during traveling is as follows.
Returning to FIG. 4, the current signal I from the current sensor 7 will be described.
_B (charging / discharging current) is input (step 70), and the current signal I _B is integrated with the _second battery capacity VI ₂ to obtain the remaining capacity during traveling, and the data is transferred to the display 10. At the same time, the above data is transferred to the power generation control circuit 11.

Step 90 is a time adjustment for measuring the charging / discharging current every 10 ms. In step 100, OFF of the key switch 1 is detected, and steps 70 to 90 are repeated until the key switch 1 is turned OFF, and the second battery capacity VI ₂ is continuously obtained. When it is detected in step 100 that the key switch is off, the process proceeds to step 110, and the second battery capacity VI ₂ thus obtained is stored as the third battery capacity VI ₃ .

(3) Power Generation Control The power generation control circuit 11 shown in FIG. 2 inputs the voltage of the battery 2, the remaining battery capacity value of the battery capacity detection circuit 9 during running, and the state signal of the engine 4 to input the power signal of the generator 5. The amount of power generation is controlled, and at the same time, the idle speed of the engine 2 is controlled to be high when the battery remaining capacity value is reduced to perform optimal charging control of the battery 1.

[Brief description of drawings]

FIG. 1 is a diagram showing a battery status display unit.

FIG. 2 is a diagram showing a power system of a vehicle.

FIG. 3 is a block diagram showing processing functions in a battery capacity detection circuit.

FIG. 4 is a flowchart showing control in a battery capacity detection circuit.

FIG. 5 is a flowchart detailing step 20 of the above flowchart.

6 is a flowchart detailing step 30 of the flowchart of FIG.

FIG. 7 is a characteristic diagram showing a relationship between a battery capacity and a terminal voltage.

FIG. 8 is a characteristic diagram showing a relationship between charging efficiency and battery capacity.

FIG. 9 is a diagram used for explaining that the increase state of the battery capacity with respect to the charging current differs between a new product and a deteriorated one.

10 is a flowchart detailing step 60 of the flowchart of FIG.

[Explanation of symbols]

 2 Battery 9 Battery capacity detection circuit 10 Indicator

Claims (2)

[Claims] 1. A battery state comprising: means for detecting a chargeable capacity of a battery; means for detecting an actual capacity of the battery; and means for displaying the chargeable capacity of the battery and an actual capacity of the battery. Display device. 2. A battery current detecting means for detecting a charging / discharging current of a battery, a battery voltage detecting means for detecting a terminal voltage of the battery, and an integration of the charging / discharging current of the battery detected by the battery current detecting means. A battery current accumulating unit, and a first voltage based on the voltage of the battery detected by the battery voltage detecting unit when the charging / discharging current of the battery detected by the battery current detecting unit has a predetermined value.
First battery capacity detecting means for detecting the battery capacity of the first battery, and the first battery capacity detecting means for detecting the first battery capacity detecting means.
Initial capacity setting means for setting the initial capacity of the battery based on the battery capacity of the first battery capacity detection means, and the initial capacity set by the initial capacity setting means. Second battery capacity detecting means for detecting the second battery capacity by adding the battery current integrated value of the second battery capacity, and the difference between the first battery capacity and the second battery capacity immediately before the first battery capacity detection. A battery state display device comprising: a calculation unit that calculates the chargeable capacity of the battery based on the calculation unit; and a display unit that displays the second battery capacity and the chargeable capacity.