JP2002186104A - Method for computing battery capacity and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately compute the charged state of a battery without being affected by polarization. SOLUTION: A residual voltage drop value storing means 27 is provided that stores the difference between a value of a presumed voltage of a battery 13 in a constant load discharging, which is a voltage presumed using voltage- current characteristics, while a discharging current in a constant load discharging by the battery 12 in a state of equilibrium decreases from a current value sufficient to eliminate discharging side polarization that has occurred to the battery 13, at least immediately prior to the discharge and a value of an open circuit voltage, which is a terminal voltage of the battery 13 in the state of equilibrium before the constant load discharging used for presuming the presumed voltage starts, as a value of the residual voltage drop, which is the residual voltage drop amount affected by residual polarization when the discharging of the battery 13 is finished. A current charging capacity of the battery 13 is calculated by adding the residual voltage drop value stored by the means 27 to the estimated voltage of the battery 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for calculating a charging capacity of a battery for supplying power to a load of a vehicle, and more particularly, to a method of calculating a terminal voltage and a discharging current of a battery which are periodically measured. The present invention relates to a method and apparatus for estimating an estimated voltage, which is an estimated terminal voltage in a constant load discharge state of a battery, using the voltage-current characteristics obtained from the above, and calculating the charge capacity of the battery using the estimated voltage.

[0002]

2. Description of the Related Art As a propulsion drive source in a conventional vehicle, an engine using gasoline, light oil or the like as a fuel is mainstream, but in recent years, an electric motor that does not directly discharge combustion gas is used solely or as an auxiliary motor. Vehicles used as propulsion drive sources have appeared, and in vehicles equipped with such an electric motor, it is necessary to know the charge capacity of the battery that supplies power to the electric motor to determine the possible driving distance and the like. Important above.

[0003] Conventionally, a current integration method and a power integration method for obtaining the current charge capacity by subtracting the integrated power consumption determined using the integrated value of the discharge current from the full charge capacity of the battery are conventionally used. However, in this method,
Since the original full charge capacity changes depending on the individual difference of the battery, the degree of progress of deterioration, and the like, the current charge capacity of the battery cannot be accurately determined.

Further, since there is a certain linear correlation between the specific gravity of the electrolyte of the battery and the state of charge, it should be possible to grasp the state of charge of the battery by measuring the specific gravity of the electrolyte. Actually, in a battery during or immediately after charging / discharging, the specific gravity of the electrolyte becomes non-uniform due to a chemical reaction occurring between the electrolyte and the electrode. It is not possible to accurately measure the state of charge of the battery by measuring.

Further, it is conceivable to measure the terminal voltage of the battery to determine the charge capacity of the battery. However, since the terminal voltage is not stable unless the discharge current is stabilized, there is actually a correlation with the state of charge of the battery. The terminal voltage cannot be expected to be obtained by measurement.

Further, as shown in the characteristic diagram of FIG. 12, when the battery is discharged at a constant current of 10 to 80 (A) in steps of 10 A, the discharge time (horizontal axis) and the terminal voltage of the battery (V: The correlation with the vertical axis) is different from each other in that the smaller the discharge current, the longer the discharge time, but is common in that the terminal voltage of the battery drops sharply as the discharge time elapses.

[0007] Here, the horizontal axis of the characteristic diagram of FIG. 12 is time, but in consideration of the constant current discharge and the fact that the battery capacity is represented by the quantity of electricity (Ah), the horizontal axis is It can be considered as good as battery capacity.

Therefore, when the characteristic diagram of FIG. 12 is viewed as a correlation between the battery capacity on the horizontal axis and the terminal voltage on the vertical axis at the time of constant current discharge, the smaller the discharge current, the more power can be taken out. It can be seen that the capacity drop is slow in the vicinity of the fully charged state of the battery near the vertical axis, and the capacity drops rapidly as the distance from the vertical axis to the right side in FIG.

From the above, even if the discharge current can be stabilized, there is no linear correlation between the charge capacity of the battery and the terminal voltage. Therefore, the charge capacity is obtained from the terminal voltage of the battery. It turns out that you can't do that.

Attention has been paid to the relationship between the electrolyte specific gravity of the battery, which has a substantially linear correlation, and the open circuit voltage (terminal voltage in the open circuit state of the battery in an equilibrium state). This is a capacity calculation method that uses a relationship between the state of charge of the battery and the open circuit voltage, which should have a linear correlation from the relationship between the specific gravity of the electrolyte of the battery and the state of charge.

However, the only weak point of this capacity calculation method is that
The open circuit voltage of the battery can be measured only during non-discharge without change in charge state except spontaneous discharge. In other words, the open circuit voltage of the battery is measured during discharge when the charge state changes. That is not possible.

Therefore, the most important point in using the capacity calculation method utilizing the relationship between the state of charge of the battery and the open circuit voltage is how to find the open circuit voltage when the battery is discharged. .

By the way, what can be measured when the battery is discharged are the terminal voltage and the discharge current of the battery.
It is clear from the characteristic diagram that even if the charge state of the battery does not change, if the discharge current increases, the terminal voltage of the battery decreases. Therefore, the voltage − There are current characteristics (IV characteristics)
It can be seen that the voltage-current characteristics showing this negative correlation change when the state of charge of the battery changes.

In order to determine a plurality of voltage-current characteristics of the battery according to the state of charge of the battery, the following measurement is performed.

First, a certain current I_aAnd this current I_athan
Low current I_bAnd a pulse-like current that alternates periodically
The battery is continuously discharged by the
Battery terminal voltage and discharge current appearing in phase opposite to current
Pair (I_a, V₁), (I _b, V_Two), (I_a,
V_Three), (I_b, V_Four), ... is the pulse period of the discharge current
(For example, 1 ms) and a predetermined number (for example, 10
0 sample).

A set (I _a , V ₀₁ ) of a battery terminal voltage and a discharge current sampled by a predetermined number, (I _b ,
V ₀₂ ), (I _a , V ₀₃ ), (I _b , V ₀₄ ),..., By the least squares method, the coefficients a ₁ , V 2 in the linear voltage-current characteristic equation of the battery of V = a ₁ I + b ₁ to obtain b _1,
This equation V = a ₁ I + b ₁ is positioned as a battery voltage-current characteristic corresponding to the capacity during the sampling.

Next, a pulse is generated by the same discharge as described above.
Current I_a, I_aBattery discharge
At that time, the battery that appears in phase opposite to the discharge current
A set of terminal voltage and discharge current (I_a, V₁₁), (I_b, V
₁₂), (I_a, V₁₃), (I _b, V₁₄), ... in succession
A predetermined number of samples are taken, and
V = a_TwoI + b_TwoThe linear voltage-voltage of the battery
Coefficient a in the flow characteristic equation _Two, B_TwoAnd the equation V = a
_TwoI + b_TwoIs the capacity during the sampling described above.
Battery voltage-current characteristics corresponding to
You.

[0018] Thereafter, _{similarly, V = a n I + b} n becomes linear voltage of the battery - to obtain coefficient in current characteristic equation a _n, the b _n, the equation _{V = a n I + b n} , gradual battery Voltage corresponding to different capacitances
By positioning the battery as a current characteristic, a voltage-current characteristic of the battery corresponding to each capacity from 100% to 0% is obtained.

Incidentally, a set (I _a , V _n1 ), (I _b , V V) of the battery terminal voltage and the discharge current of each predetermined number of sampled batteries.
_{n2), (I a, V} n3), (I b, V n4), ... and, linear voltage obtained by applying the method of least squares to these - current characteristic equation V = relation between a _n I + b _n Is schematically shown in FIG.

Here, the virtual current value Is, which is a virtual constant current value, is substituted for each of the battery voltage-current characteristic equations corresponding to the respective capacities obtained as described above. When defined as an estimated voltage Vn, which is an estimated terminal voltage in the constant load discharge state, a constant current discharge characteristic as shown in the graph of FIG. 14 is obtained.

When any positive value is substituted for the virtual current value Is, the constant current discharge characteristic based on the virtual current value Is is such that the capacity on the horizontal axis advances to the right in FIG.
, The estimated voltage Vn sharply decreases, and the constant current discharge characteristic exhibits the same characteristic even in the case of a virtual current value Is = 0 A, which should theoretically indicate an open circuit voltage. You can see that.

However, according to the graph of FIG. 14, the smaller the virtual current value Is, the smaller the estimated voltage Vn decreases as the capacity approaches 0, and thus is a virtual region. By substituting a negative value as the virtual current value Is into the battery voltage-current characteristic equation corresponding to each capacity obtained as described above, a constant current discharge characteristic based on the negative virtual current value Is is plotted. In this case, as shown in FIG. 15, the virtual current value I
Estimated voltage Vn in a region near capacity 0 with s = −10 A as a boundary
Characteristic changes.

Therefore, in theory, the virtual current value Is
Is −10 A, the estimated voltage Vn at the constant current discharge
Shows a linear characteristic with respect to the capacity of the battery.

Therefore, the voltage-current characteristics of the battery according to the respective capacities obtained as described above are developed on the same plane with the discharge current I on the ordinate and the terminal voltage V on the abscissa.
6, the estimated voltage V at the constant current discharge
Let us verify that n shows a linear characteristic with respect to the capacity of the battery.

Firstly, the voltage - coefficients a _1, a ₂ representing the gradient of the current characteristic equation, ..., unlike each a _n, and each voltage -
Since the coefficients b ₁ , b ₂ ,..., B _n representing the intercepts of the current characteristic equation are also different from each other, in the actually existing positive discharge current region in FIG. Does not exist.

However, in the negative discharge current region, which is an imaginary region in FIG. 16, when the discharge current value I = -10 A, the terminal voltage V changes linearly with respect to the battery capacity. The discharge current value I = -1
Terminal voltage V of the battery corresponding to each capacity at 0 A
Is the estimated voltage Vn.

The relationship between the capacity of the battery at the virtual current value Is = −10 A and the estimated voltage Vn having a linear correlation with the battery capacity is represented by a graph, as shown in FIG. The estimated voltage Vn exists between the open circuit voltage Vs at the time of full charge and the open circuit voltage Ve at the end of discharge, and the value on the capacity of the horizontal axis corresponding to the estimated voltage Vn is the remaining battery capacity. Capacity, that is, state of charge SOC
(State of charge).

Therefore, it can be said that the estimated voltage Vn is a substitute for the open circuit voltage of the battery. Even at the time of discharge where the open circuit voltage cannot be measured, the discharge does not change during the discharge of the load for supplying power. In the case of constant load discharge, by measuring the battery terminal voltage and the discharge current that fluctuate slightly during the discharge, the voltage − which is the correlation between the battery terminal voltage and the discharge current in the constant load discharge,
By obtaining the current characteristic and substituting the virtual current value Is = −10 A into the characteristic formula (V = aI + b) to obtain the estimated voltage Vn, the state of charge SO of the battery is calculated from the estimated voltage Vn.
C can be determined.

Then, the current state of charge SOC with respect to the full charge capacity is calculated by converting the ratio between the estimated voltage Vn on the vertical axis of FIG. 17 and the open circuit voltage Vs at the time of full charge. SOC = ｛(Vn −Ve) / (Vs−Ve)｝ × 100
(%).

However, for accuracy, the power (V × Ah)
And the current state of charge SO relative to the full charge capacity
When C is obtained, SOC = {[(Vn + Ve) / 2] × [(Vn−Ve) / (Vs−Ve)] × Ah} / {[(Vs + Ve) / 2] × Ah} × 100 (%) = {(Vn ² −Ve ² ) / (Vs ² −Ve ² )} × 100 (%).

[0031]

As shown in FIG. 18, during the discharge of the battery, a voltage drop due to the influence of the pure resistance (the ohmic resistance of the battery), that is, the IR drop obtained by multiplying the pure resistance by the discharge current. A voltage drop occurs due to a drop or a discharge-side polarization. Conversely, a voltage rise due to the influence of these pure resistances or a voltage rise due to the charge-side polarization occurs during charging of the battery.

In particular, as shown in FIG. 18, the activation polarization for promoting the oxidation-reduction reaction on the surface of the electrode, which is included in the discharge-side polarization generated when the battery is discharged, and the surface of the electrode as a result of mass transfer. Concentration polarization due to the difference in concentration of reactants and products generated with the solution bulk reacts with a slight delay to increase or decrease in discharge current, and does not show a linear correlation proportional to the value of discharge current. .

Therefore, as described above, when the estimated voltage Vn is obtained instead of the open circuit voltage of the battery, which cannot be measured at the time of discharging, in order to obtain the state of charge SOC of the battery, the terminal voltage and the discharging current are determined as the preceding steps. Is measured during discharge to determine the voltage-current characteristics of the battery. Since the terminal voltage of the battery includes a voltage drop due to polarization at the time of discharge, the obtained voltage-current characteristics of the battery and the voltage-current characteristics are obtained.
The estimated voltage Vn estimated from the current characteristics reflects not only the state of charge SOC of the battery but also a voltage drop due to polarization. Therefore, if the estimated voltage Vn is used as it is, the state of charge SOC of the battery is reduced. I can't find it exactly.

The present invention has been made in view of the above circumstances,
An object of the present invention is to obtain a state of charge of a battery using an estimated voltage which is an estimated terminal voltage in a constant load discharge state of a battery, which is obtained from a correlation between a terminal voltage of the battery and a discharge current which can be measured at the time of discharging. The terminal voltage of the discharging battery used to determine the estimated voltage is
A battery capacity calculation method capable of accurately calculating the state of charge of a battery even when the voltage rise or voltage drop due to the previous charge or discharge is not completely eliminated, and the method is implemented. It is another object of the present invention to provide a battery capacity calculation device suitable for use in such a case.

[0035]

According to a first aspect of the present invention, there is provided a method of calculating a battery capacity, and the seventh aspect of the present invention is directed to a method of calculating a battery capacity. The present invention relates to a capacity calculation device.

In the battery capacity calculation method according to the present invention, a terminal voltage and a discharge current of a battery for supplying power to a vehicle load are periodically measured, and the terminal voltage and the discharge current are measured. And a voltage-current characteristic indicating the correlation between the two is calculated, an estimated voltage which is an estimated terminal voltage in the constant load discharge state of the battery is estimated using the voltage-current characteristic, and the battery is charged using the estimated voltage. In calculating the capacity, the discharge current of the constant load discharge by the battery in an equilibrium state is at least reduced from a current value sufficient to eliminate the charging side polarization generated in the battery immediately before the discharge. , Estimated using the voltage-current characteristic, used to estimate the value of the estimated voltage of the battery at the time of constant load discharge with the predetermined large current value, and the value of the estimated voltage. The difference between the terminal voltage of the battery in an equilibrium state before the start of the constant load discharge and the value of the open circuit voltage, which is the terminal voltage of the battery, is determined by the residual voltage drop which is the residual voltage drop due to the influence of residual polarization at the end of the battery discharge. After that, every time the battery performs a constant load discharge with a current value sufficient to eliminate at least the charge-side polarization generated in the battery immediately before the discharge, the constant load discharge is performed. The voltage-current characteristic is obtained from the terminal voltage and the discharge current of the battery periodically measured, and a current estimated voltage of the battery is estimated using the voltage-current characteristic. The current charge capacity of the battery is calculated by adding the remaining voltage drop value to the estimated voltage value.

According to a second aspect of the present invention, there is provided a battery capacity calculation method according to the first aspect, wherein the terminal voltage value of the battery in an equilibrium state is measured in advance. The measured value is set to the value of the open circuit voltage, and following the setting of the open circuit voltage, the battery in an equilibrium state eliminates at least the charge-side polarization that has occurred in the battery immediately before discharging. When a constant load discharge with a sufficient current value is performed, the discharge current of the constant load discharge is periodically measured while the discharge current decreases from the maximum current value. A current characteristic is obtained, and the voltage-current characteristic is used to calculate a current value at the time of constant load discharge from a state of equilibrium at a current value sufficient to eliminate at least a charge-side polarization generated in the battery immediately before discharging. Estimating the estimated voltage of the battery, and discharging the battery at constant load discharge from the estimated equilibrium state at a current value sufficient to eliminate at least the charging-side polarization that has occurred in the battery immediately before discharging. The residual voltage drop value is obtained in advance by subtracting the value of the estimated voltage from the value of the set open circuit voltage.

Further, according to a third aspect of the present invention, in the battery capacity calculating method according to the second aspect of the present invention, each time the battery is brought into an equilibrium state, the open circuit voltage is reduced. The value is updated and set to the value of the terminal voltage of the battery measured in the equilibrium state.

According to a fourth aspect of the present invention, there is provided a battery capacity calculation method according to the first, second or third aspect, wherein the battery comprises:
At least every time a constant load discharge is performed with a current value sufficient to eliminate the charge-side polarization generated in the battery immediately before the discharge, the period during which the discharge current during the constant load discharge decreases from the maximum current value The voltage-current characteristics are obtained from the terminal voltage and the discharge current of the battery, which are measured in a typical manner, and the current estimated voltage of the battery is estimated using the voltage-current characteristics.

Further, the battery capacity calculation method according to the present invention described in claim 5 is the battery capacity calculation method according to claim 1, 2, 3, or 4, wherein at least immediately before discharging the battery is operated. The current value sufficient to eliminate the charging-side polarization, which has been described above, is a predetermined large current value required at the time of starting the cell motor of the vehicle, and the discharge current value of the battery starts to decrease from the predetermined large current value. From, lower than the predetermined large current value, and more than the maximum discharge current value when the load of the vehicle other than the self-motor is driven, until the target current value is reduced, periodically From the measured terminal voltage and discharge current of the battery, the voltage-current characteristic used to estimate an estimated voltage of the battery at the time of constant load discharge with the predetermined large current value is determined. It was so.

According to a sixth aspect of the present invention, there is provided the battery capacity calculation method according to the first, second, third, fourth, or fifth aspect of the invention. Each time when estimating the estimated voltage of the battery at the time of constant load discharge with a current value sufficient to eliminate the charging-side polarization that has occurred at the time of estimation, the ambient temperature of the battery at the estimation time and the open circuit voltage Check the presence or absence of a difference from the ambient temperature of the battery at the time of the determination, and if there is a difference, according to the temperature difference,
The remaining voltage drop value is corrected, and the current charge capacity of the battery is calculated using the corrected remaining voltage drop value.

Further, according to the battery capacity calculation device of the present invention, as shown in the basic configuration diagram of FIG.
At the time of constant load discharge of the battery 13 that supplies power to the load of the vehicle at a current value sufficient to eliminate at least the charge-side polarization that has occurred in the battery 13 immediately before discharging, the battery 13 in this constant load discharge Are periodically measured to obtain a voltage-current characteristic indicating a correlation between the terminal voltage and the discharge current, and the voltage-current characteristic is used to estimate the battery 13 in a constant load discharge state. In the battery capacity calculating device for estimating the estimated voltage which is the upper terminal voltage and calculating the charging capacity of the battery 13 using the estimated voltage,
3 while the discharge current of the constant load discharge by 3 is decreasing from at least a current value sufficient to eliminate the charge-side polarization generated in the battery 13 immediately before the discharge. The battery 13 at the time of constant load discharge with a current value sufficient to eliminate at least the estimated charging-side polarization generated in the battery 13 immediately before discharging is estimated.
The difference between the value of the estimated voltage and the value of the open circuit voltage which is the terminal voltage of the battery 13 in an equilibrium state before the start of the constant load discharge used to estimate the value of the estimated voltage,
A residual voltage drop value storage unit that stores a residual voltage drop value that is an amount of residual voltage drop due to the effect of residual polarization at the end of discharging of the battery; The present invention is characterized in that the current charge capacity of the battery 13 is calculated by adding the remaining voltage drop value to the value of the estimated voltage of the battery 13.

The battery capacity calculating device according to the present invention as set forth in claim 8 is the battery capacity calculating device according to claim 7, wherein at least the charge-side polarization generated in the battery 13 immediately before discharging. Discharge current decrease start detecting means A for detecting that the discharge current of the battery 13 has started to decrease from the maximum current value in a constant load discharge of the battery 13 with a current value sufficient to eliminate
After the discharge current decrease start detecting means A detects that the discharge current of the battery 13 has started decreasing from the maximum current value, the voltage-is calculated from the terminal voltage of the battery 13 and the discharge current which are periodically measured. Using the characteristic determining means 23A for determining the current characteristic and the voltage-current characteristic determined by the characteristic determining means 23A, at least enough to eliminate the charging-side polarization generated in the battery 13 immediately before discharging. And an estimated voltage estimating means 23B for estimating an estimated voltage of the battery 13 at the time of constant load discharge with a large current value. The estimated voltage value of the battery 13 estimated by the estimated voltage estimating means 23B is The current charge capacity of the battery 13 is calculated by adding the remaining voltage drop values stored in the remaining voltage drop value storage means 27.

Further, according to a ninth aspect of the present invention, there is provided the battery capacity computing device according to the eighth aspect of the present invention, wherein the open circuit voltage value storage means stores the value of the open circuit voltage. 25 and equilibrium state determination means 23 for determining whether or not the battery 13 is in an equilibrium state.
C and a current value from the battery 13 determined to be in an equilibrium state by the equilibrium state determination means 23C at least by a current value sufficient to eliminate the charge-side polarization generated in the battery 13 immediately before discharging. At the time of load discharge, the value of the estimated voltage of the battery 13 estimated by the estimated voltage estimating means 23B is subtracted from the value of the open circuit voltage stored in the open circuit voltage value storage means 25 to obtain the remaining voltage drop value. There is further provided a remaining voltage drop value calculating means 23D to be obtained, and the remaining voltage drop value storing means 27 stores the remaining voltage drop value obtained by the remaining voltage drop value calculating means 23D.

The battery capacity calculating device according to the present invention as set forth in claim 10 is the battery capacity calculating device according to claim 9, wherein the equilibrium state determining means 23 is provided.
C is a state where the terminal voltage of the battery 13 is measured in a state determined to be in an equilibrium state, and the value of the open circuit voltage stored in the open circuit voltage value storage means 25 is: An open circuit voltage updating means 23E for updating the terminal voltage value of the battery 13 measured by the equilibrium terminal voltage measuring means B is further provided.

Further, according to the battery capacity calculating device of the present invention described in claim 11, in the battery capacity calculating device of the present invention described in claim 10, temperature detecting means 19 for detecting the ambient temperature of the battery 13; The battery 1
At the time when the estimated voltage estimating means 23B estimates the estimated voltage of the battery 3 and the terminal temperature of the battery 13 detected by the temperature detecting means 19, and the terminal voltage of the battery 13 is measured by the balanced state terminal voltage measuring means B. The battery 1 detected by the temperature detecting means 19
Check if there is a difference from the ambient temperature of 3 and if there is a difference,
According to the temperature difference, the remaining voltage drop value storage means 27
Correction means 2 for correcting the residual voltage drop value stored in memory
3F, and when the remaining voltage drop value is corrected by the correction means 23F, the corrected remaining voltage drop value is used as the estimated voltage of the battery 13 estimated by the estimated voltage estimation means 23B. By adding to the value of
The current charge capacity of the battery 13 is calculated.

According to a twelfth aspect of the present invention, there is provided a battery capacity calculating device according to the eighth, ninth, tenth, or eleventh aspect of the present invention, wherein at least immediately before discharging, The current value sufficient to eliminate the charge-side polarization, which has been performed, is a predetermined large current value required at the time of starting the cell motor 5 of the vehicle. In the load discharge, it is configured to detect that the discharge current of the battery 13 has started decreasing from the predetermined large current value, and to detect that the discharge current has started decreasing from the predetermined large current value. A target current value equal to or greater than a maximum discharge current value when the load of the vehicle other than the starter motor 5 is driven when the discharge current of the battery 13 detected by the start detection means A is driven; Further comprising a discharge current drop detection means C for detecting that reduced, the characteristics indexing means 2
3A, the discharge current decrease start detecting means A detects that the discharge current of the battery 13 has started to decrease from the predetermined large current value, and then detects that the discharge current has decreased to the target current value. Until the detection by the means C, the voltage-current characteristic is determined from the terminal voltage of the battery 13 and the discharge current measured periodically.

According to the battery capacity calculation method of the present invention, the discharge current of the constant load discharge performed by the battery is at least sufficient to eliminate the charge-side polarization generated in the battery immediately before the discharge. If the current value reaches a certain value, even if the voltage drop or voltage rise due to the polarization on the discharge side or the charge side that occurred in the previous discharge remains before the start of the discharge,
A state in which discharge-side polarization of a magnitude corresponding to the discharge current value exceeding the remaining voltage drop occurs, or a discharge of a magnitude corresponding to the discharge current value after the remaining voltage rise is eliminated. A state in which side polarization newly occurs is obtained.

On the other hand, even if the battery in the equilibrium state performs a constant load discharge with a current value sufficient to eliminate at least the charging side polarization generated in the battery immediately before the discharge,
When the discharge current value is reached, discharge-side polarization of a magnitude corresponding to the discharge current value occurs.

Therefore, when the battery performs a constant load discharge at a current value sufficient to eliminate at least the charge-side polarization generated in the battery immediately before the discharge, the battery is brought into an equilibrium state before the start of the constant load discharge. , Or at least the charge-side polarization that occurred in the battery immediately before discharge, regardless of whether the polarization state on the discharge side or the charge side that occurred in the previous discharge was not completely eliminated. The estimated voltage of the battery, which is estimated from the voltage-current characteristics obtained from the terminal voltage of the battery and the discharge current while the discharge current is decreasing from the current value sufficient to perform the operation, has the same value.

Then, regardless of whether or not the battery was in an equilibrium state before the start of the constant load discharge with a current value sufficient to eliminate at least the charge side polarization generated in the battery immediately before the discharge, the constant load is maintained. The value of the estimated voltage estimated after the battery started discharging is the value obtained when the battery was in an equilibrium state before starting the constant load discharging.
At the end of the constant-load discharge performed by the battery with an open circuit voltage corresponding to the terminal voltage of the battery in the equilibrium state, at least a current value sufficient to eliminate the charging-side polarization generated in the battery immediately before discharging. A lower value is shown by the residual voltage drop value obtained in advance as the residual voltage drop due to the residual polarization.

Further, according to the battery capacity calculation method of the present invention described in claim 2, in the battery capacity calculation method of the present invention described in claim 1, a battery in an equilibrium state is generated in the battery at least immediately before discharging. When constant-load discharge is performed with a current value sufficient to eliminate the charging-side polarization, the value of the open-circuit voltage is set by measuring the terminal voltage of the battery before the start of constant-load discharge. Subsequently, when the discharge current value of the constant load discharge decreases from at least a current value sufficient to eliminate the charge-side polarization generated in the battery immediately before the discharge, when the terminal voltage of the battery periodically measured and the An estimated voltage is estimated from the voltage-current characteristic obtained from the discharge current, and a difference between the value of the estimated voltage and the value of the previously set open circuit voltage is obtained as a residual voltage drop value. Is performed to calculate the present charging capacity of the battery, the battery is to be subjected to the addition to the current estimated voltage of the battery which is estimated every time the constant load discharge.

Further, according to the battery capacity calculation method of the present invention described in claim 3, in the battery capacity calculation method of the present invention described in claim 2, the battery that changes in accordance with the change in the state of charge due to discharging. Is updated and set to the latest terminal voltage value each time the battery is in a balanced state.

According to the battery capacity calculating method of the present invention described in claim 4, in the battery capacity calculating method of the present invention described in claim 1, 2, or 3, the battery is connected to the battery at least immediately before discharging. When a constant load discharge is performed with a current value sufficient to eliminate the charging-side polarization that has occurred, the terminal voltage of the battery periodically measured while the discharge current value decreased from the maximum current value each time The current estimated voltage of the battery is estimated using the voltage-current characteristics obtained from the discharge current, and the current state of charge of the battery is calculated from the estimated voltage value and the remaining voltage drop value. .

Further, according to the battery capacity calculation method of the present invention described in claim 5, in the battery capacity calculation method of the present invention described in claim 1, 2, 3, or 4, it is necessary to start the vehicle at the start of the cell motor. Since the predetermined large current value exceeds the current value even when a plurality of electric powers from the battery are simultaneously supplied to other loads of the vehicle, the predetermined large current value is necessary at the time of starting the cell motor. By setting the predetermined large current value to be a current value sufficient to eliminate at least the charging side polarization generated in the battery immediately before discharging, when the discharging current reaches the predetermined large current value, A state in which a voltage drop exceeding the voltage drop due to the discharge-side polarization generated by the previous discharge occurs in the terminal voltage of the battery occurs.

On the other hand, when the discharge current value of the battery decreases from a predetermined large current value and decreases to a target current value equal to or higher than the maximum discharge current value when a load of a vehicle other than the self-motor is driven, in that state, In the voltage drop due to the polarization on the discharge side remaining in the terminal voltage of the battery, the voltage drop component due to the polarization on the discharge side generated by supplying power to the load of the vehicle other than the self-motor does not appear on the surface, and the predetermined large current Only the remaining components of the voltage drop due to the discharge-side polarization generated by performing the discharge by the value except for the portion eliminated by the decrease in the discharge current to the target current value appear on the surface.

Therefore, the terminal periodically measured during the period from the time when the discharge current value of the battery that has been subjected to the constant load discharge at the predetermined large current value decreases from the predetermined large current value to the target current value is reduced. When the voltage-current characteristics of the battery are obtained from the voltage and the discharge current, the estimated voltage estimated from the voltage-current characteristics is a predetermined large current value even if the load of the vehicle other than the self-motor is still being driven. Of the voltage drop due to the polarization on the discharge side generated by the discharge due to the discharge current, only the remaining component excluding the portion eliminated by the discharge current falling to the target current value is purely reflected.

According to the battery capacity calculation method of the present invention as set forth in claim 6, claim 1, 2, 3, 4, or 5 is provided.
In the battery capacity calculation method of the present invention described in the above, if the ambient temperature of the battery changes, the capacity of the battery changes and the terminal voltage appearing at the battery terminal also changes.
The time at which the open circuit voltage of the battery in the equilibrium state was obtained, and the time at which the estimated voltage of the battery at the time of constant load discharge at least with a current value sufficient to eliminate the charging-side polarization generated in the battery immediately before the discharge. When the ambient temperature of the battery is different, the terminal voltage component reflected on the open circuit voltage according to the ambient temperature of the battery and the terminal voltage component reflected on the estimated voltage according to the ambient temperature of the battery are:
Each will be different.

However, the constant load discharge by the ambient temperature of the battery at the time when the open circuit voltage of the battery in the equilibrium state is obtained and at least a current value sufficient to eliminate the charging side polarization generated in the battery immediately before the discharge. When the current charge capacity of the battery is calculated using the corrected residual voltage drop value corrected according to the battery's ambient temperature at the time of estimation of the battery's estimated voltage at the time, a terminal corresponding to the battery's peripheral temperature is calculated. The current state of charge of the battery is calculated using the open-circuit voltage and the estimated voltage in which the voltage component is reflected under the same conditions, with the fluctuation component of the terminal voltage due to the difference in the ambient temperature of the battery being eliminated. become.

Further, according to the battery capacity calculation device of the present invention, as shown in FIG. 1, the discharge current of the constant load discharge performed by the battery 13 is generated in the battery 13 at least immediately before the discharge. If the current reaches a value sufficient to eliminate the charge-side polarization, the voltage drop or voltage rise due to the discharge-side or charge-side polarization that occurred in the previous discharge, even if it remains before the start of discharge, A state in which discharge-side polarization having a magnitude corresponding to the discharge current value exceeding the remaining voltage drop has occurred, or the residual voltage rise has been eliminated, and then the discharge side having a magnitude corresponding to the discharge current value Polarization is newly generated.

On the other hand, even if the battery 13 in an equilibrium state performs a constant load discharge at a current value sufficient to eliminate at least the charge-side polarization generated in the battery 13 immediately before discharging, the discharge current value is When the discharge current reaches the value, discharge-side polarization of a magnitude corresponding to the discharge current value occurs.

Therefore, when the battery 13 performs a constant load discharge at a current value sufficient to eliminate at least the charge-side polarization that has occurred in the battery 13 immediately before the discharge, the battery 13 is charged before the start of the constant load discharge. Is in an equilibrium state, or whether the polarization state on the discharge side or the charge side generated in the previous discharge has not been completely eliminated, at least immediately before the discharge.
The battery 13 estimated from the voltage-current characteristic obtained from the terminal voltage and the discharge current of the battery 13 while the discharge current is decreasing from the current value sufficient to eliminate the charge-side polarization generated in the battery 3 Have the same value.

At least immediately before discharging, the battery 1
3 after the battery 13 has started its constant load discharge, regardless of whether the battery 13 was in an equilibrium state before the start of the constant load discharge with a current value sufficient to eliminate the charging-side polarization that occurred in 3. The value of the estimated voltage is at least immediately before the discharge with respect to the open circuit voltage corresponding to the terminal voltage of the battery 13 in the equilibrium state, assuming that the battery 13 was in the equilibrium state before starting the constant load discharge. The remaining voltage is determined in advance as a residual voltage drop due to the influence of residual polarization at the end of constant load discharge performed by the battery 13 with a current value sufficient to eliminate the charging side polarization generated in the battery 13. A lower value is indicated by the remaining voltage drop value stored in the drop value storage means 27.

According to the battery capacity calculating device of the present invention described in claim 8, in the battery capacity calculating device of the present invention described in claim 7, the battery 13 is generated in the battery 13 at least immediately before discharging. When a constant load discharge is performed with a current value sufficient to eliminate the charging-side polarization, the discharge current decrease start detection unit A detects that the discharge current of the battery 13 has started to decrease from the maximum current value. The voltage-current characteristic is determined by the characteristic determining means 23A from the terminal voltage of the battery 13 and the discharging current measured periodically while the discharge current value decreases from the maximum current value, and the characteristic-determining means 23A determines the voltage-current characteristic. Using the obtained voltage-current characteristics, at least the battery at the time of constant load discharge with a current value sufficient to eliminate the charge-side polarization generated in the battery 13 immediately before the discharge. Estimating voltage Terri 13 is estimated by the estimation voltage estimating means 23B, the estimated voltage estimating unit 2
From the value of the estimated voltage estimated by 3B and the remaining voltage drop value stored in the remaining voltage drop value storage means 27,
The current state of charge of the battery 13 is calculated.

Further, according to the battery capacity calculation device of the present invention described in claim 9, in the battery capacity calculation device of the present invention described in claim 8, the equilibrium state determination means 2
Battery 13 determined to be in equilibrium by 3C
Performs constant-load discharge with a current value sufficient to eliminate at least the charge-side polarization that has occurred in the battery 13 immediately before discharging, and the residual voltage drop value determining means 23D
After the discharge current decrease start detecting means A detects that the discharge current of the battery 13 has started to decrease from the maximum current value, the value of the estimated voltage estimated by the estimated voltage estimating means 23B is stored in the open circuit voltage value storing means 25. Is subtracted from the value of the open circuit voltage stored in
The obtained residual voltage drop value is stored in the residual voltage drop value storage means 27.

According to the battery capacity calculating device of the present invention described in claim 10, in the battery capacity calculating device of the present invention described in claim 9, the charge of the battery 13 according to the change in the state of charge accompanying the discharge is obtained. Even if the open circuit voltage changes, each time the equilibrium state determination unit 23C determines that the battery 13 is in an equilibrium state, the open circuit voltage value storage unit 2
The value of the open circuit voltage stored in 5 is updated to the latest value of the terminal voltage of the battery 13 in the equilibrium state measured by the equilibrium state terminal voltage measuring means B.

Further, according to the battery capacity calculation device of the present invention described in claim 11, in the battery capacity calculation device of the invention described in claim 10, when the ambient temperature of the battery 13 changes, the capacity of the battery 13 is changed. Changes, and the terminal voltage appearing at the terminal of the battery 13 also changes.
At the time when the open circuit voltage stored in the open circuit voltage value storage means 25 is obtained, the discharge current of the battery 13 determined to be in an equilibrium state by the equilibrium state determination means 23C starts to decrease from a predetermined large current value. After the discharge current decrease start detecting means A has detected that, the estimated voltage of the battery 13 is estimated by the estimated voltage estimating means 23B.
If the ambient temperature of the battery 13 detected by
The terminal voltage component reflected on the open circuit voltage according to the peripheral temperature of the battery 13 and the terminal voltage component reflected on the estimated voltage according to the peripheral temperature of the battery 13 are different from each other.

However, when the open-circuit voltage stored in the open-circuit voltage value storage means 25 is obtained, the ambient temperature of the battery 13 detected by the temperature detection means 19 and the equilibrium state by the equilibrium state determination means 23C are determined. The determined discharge current of the battery 13 is at least immediately before the discharge.
After the discharge current decrease start detecting unit A detects that the current has started to decrease from the current value sufficient to eliminate the charging-side polarization that has occurred, the estimated voltage of the battery 13 is estimated by the estimated voltage estimating unit 23B. At this time, even if the ambient temperature of the battery 13 detected by the temperature detecting means 19 is different from the ambient temperature, the residual voltage drop value stored in the residual voltage drop value storing means 27 is corrected according to the two peripheral temperatures. By calculating the current charge capacity of the battery 13 using the residual voltage drop value corrected by the correction unit 23F, the terminal voltage component corresponding to the ambient temperature of the battery 13 is maintained under the same condition. Using the reflected open circuit voltage and the estimated voltage, the current charge state of the battery 13 is changed in a state where the fluctuation component of the terminal voltage due to the difference in the ambient temperature of the battery 13 is eliminated. It will be calculated.

According to the battery capacity calculating device of the present invention described in claim 12, in claim 8, 9, 10 or 1
In the battery capacity calculation device according to the first aspect of the invention,
The predetermined large current value required at the time of starting the cell motor 5 of the vehicle is the current value in that case even if a plurality of electric powers from the battery 13 are simultaneously supplied to other loads of the vehicle. Therefore, the predetermined large current value required at the time of starting the starter motor 5 is set at least to a current value sufficient to cause the polarization on the charge side generated in the battery 13 immediately before discharging, so that the battery 13 When the discharge current decrease start detecting means A detects that the discharge current of the load discharge has started to decrease from the maximum current value, the discharge current once reaches a predetermined large current value before that, and is generated by the previous discharge. This means that a voltage drop exceeding the voltage drop due to the discharge-side polarization has occurred in the terminal voltage of the battery 13.

Then, the fact that the discharge current value of the battery 13 has decreased from the predetermined large current value and has decreased to the target current value equal to or greater than the maximum discharge current value when the load of the vehicle other than the starter motor 5 is driven. At the time when the discharge current drop detecting means C detects the voltage drop due to the discharge side polarization remaining in the terminal voltage of the battery 13 in that state, the voltage drop is caused by supplying power to the load of the vehicle other than the self-motor 5. The voltage drop component due to the discharge side polarization does not appear on the surface, and the voltage drop due to the discharge side polarization generated by performing the discharge with the predetermined large current value, which is eliminated by the discharge current falling to the target current value, is removed. Only the remaining components excluding have reached the state that appeared on the surface.

Therefore, after the discharge current decrease start detecting means A detects that the discharge current of the battery 13 has started to decrease from the predetermined large current value, the discharge current decrease detecting means C detects that the discharge current has decreased to the target current value. Until the detection, the characteristic determining means 23 is used based on the periodically measured terminal voltage and discharge current.
When A obtains the voltage-current characteristic of the battery 13, the estimated voltage estimated by the estimated voltage estimating means 23B from the voltage-current characteristic becomes a predetermined voltage even if the load of the vehicle other than the starter motor 5 is still being driven. Of the voltage drop due to the discharge side polarization generated by performing the discharge with the large current value,
Only the remaining components excluding the components eliminated by the decrease in the discharge current to the target current value are purely reflected.

[0072]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A battery capacity calculation method according to the present invention, together with a battery capacity calculation device according to the present invention, will be described below with reference to the drawings.

FIG. 2 is an explanatory diagram showing, in partial blocks, a schematic configuration of a battery capacity calculating apparatus according to an embodiment of the present invention to which the battery capacity calculating method of the present invention is applied.
The battery capacity calculation device according to the present embodiment, which is denoted by reference numeral 1, is mounted on a hybrid vehicle having a motor generator 5 in addition to the engine 3.

In this hybrid vehicle, normally, only the output of the engine 3 is transmitted from the drive shaft 7 to the wheels 11 via the differential case 9 to run the vehicle. The motor 5 is configured to function as a motor, and the output of the motor generator 5 is transmitted from the drive shaft 7 to the wheels 11 in addition to the output of the engine 3 to perform assist traveling.

The hybrid vehicle is configured such that the motor generator 5 functions as a generator (generator) during deceleration or braking, and converts the kinetic energy into electric energy to charge the battery 13.

The motor generator 5 is further used as a cell motor for forcibly rotating the flywheel of the engine 3 when the engine 3 is started when a starter switch (not shown) is turned on. In this case, the motor generator 5 is used. However, more electric power is consumed alone than when a plurality of other electric loads mounted on the hybrid vehicle are operating at the same time.

In the hybrid vehicle of the present embodiment, the starter switch is off, but an accessory switch (not shown) or an ignition switch (not shown), or a switch (not shown) of an electric component (load) other than the motor generator 5 is used. Is turned on, when the air conditioner, the audio equipment, the power window, the headlight, and the room lamp (none of which are shown) are operating, the discharge current flowing from the battery 13 is reduced to those electrical components. Is less than 35A (ampere) even if a plurality of are operating at the same time.

Conversely, when the accessory switch is turned on, and then the starter switch is turned on, and the motor generator 5 is operated as a starter motor to start the engine 3, for example, no other electrical components operate. Even if not, a discharge current that reaches approximately 250 A (ampere) flows from the battery 9 instantaneously.

Therefore, in the battery capacity computing device 1 of the present embodiment, it is determined whether the discharge current of the battery 13 is between the target current value = 35 A (lower limit) and the maximum current value = 250 A (upper limit). Generator 5
This serves as a guide for distinguishing that a constant load discharge is being performed to operate as a cell motor.

When the engine 3 is started by the motor generator 5 by turning on the starter switch, the operation of an ignition key (not shown) is released.
The starter switch is turned off and the ignition switch and the accessory switch are turned on.

Returning to the description of the configuration, the battery capacity computing device 1 of the present embodiment computes the state of charge of the battery 13 described above, and includes a motor generator 5 functioning as a motor for assisting traveling and a cell motor, and the like. , The discharge current I of the battery 13 to the electrical components, and the battery 13 from the motor generator 5 functioning as a generator.
A current sensor 15 for detecting a charging current to the battery 13 and an infinite resistance connected in parallel with the battery 13,
A voltage sensor 17 for detecting a terminal voltage V of the
And a temperature sensor 19 (corresponding to a temperature detecting means) for detecting a temperature h of an engine room (not shown) in which is disposed.

In the battery capacity computing device 1 of the present embodiment, the outputs of the above-described current sensor 15, voltage sensor 17, and temperature sensor 19 are interface circuits (hereinafter abbreviated as "I / F") 21. (Hereinafter abbreviated as “microcomputer”) 23 and nonvolatile memories (hereinafter abbreviated as “NVM”) 25 and 27 connected to the microcomputer 23. In addition.

The microcomputer 23 has a CPU 23
a, a RAM 23b, and a ROM 23c,
The CPU 23a includes a RAM 23b and a ROM 23b.
In addition to 23c, the I / F 21 and the NVMs 25 and 27 are connected to each other, and the above-described not-shown starter switch, ignition switch and accessory switch, and switches for electrical components (loads) other than the motor generator 5 are also provided. Further connected.

The RAM 23b stores various data.
Work area used for data area and various processing operations
The ROM 23c has a CPU 23a.
A control program for performing a seed processing operation;
The open circuit voltage OCV of the battery 13 is stored and stored in the VM 25.
The temperature h of the battery 13 itself or the ambient temperature at the time of the storage
₁And the constant load discharge state estimated by the processing described later.
Of the estimated voltage Vn which is the estimated terminal voltage V in the state
The temperature h of the battery 13 itself or the surroundings at a fixed time h _TwoWhen
According to the remaining and stored in the NVM 27
Voltage drop value e₀And the correction data for correcting the
Have been.

The correction data of the residual voltage drop value e ₀ stored in the ROM 23c is obtained by assuming that the correction coefficient at a temperature of 0 ° C. is “1” as shown in the graph of FIG.
This is like a table of correction coefficients at different temperatures from 0 ° C. to 55 ° C., so to speak.

The NVM 25 (corresponding to an open circuit voltage value storage means) completely stores the equilibrium state of the battery 13 that changes according to the change in the charge capacity, that is, the voltage rise and the voltage drop due to the polarization during charging and discharging. The terminal voltage V in a state where it has not been eliminated and remains is stored and stored as the open circuit voltage OCV of the battery 13, and the temperature of the engine room detected by the temperature sensor 19 at the time when the open circuit voltage OCV is stored and stored. temperature, stored as the temperature h ₁ near the battery 13 itself or stored.

Incidentally, at the initial time when the hybrid vehicle is manufactured, the terminal voltage V of the battery 13 separately measured at the time of mounting is previously stored and stored in the NVM 25 as the open circuit voltage OCV, and the open circuit voltage The temperature of the battery 13 itself or the surroundings at the time when the OCV is stored and stored is determined by the NVM as the battery 13 itself or the surrounding temperature h _1.
25 is stored in advance.

In the NVM 27 (corresponding to a residual voltage drop value storage means), when the ignition switch (not shown) is turned on, the battery 13 instantaneously discharges a constant load for starting the engine 3 by the motor generator 5. When performing the constant load, the constant load is estimated by a process described later based on the correlation between the terminal voltage V of the battery 13 and the discharge current I detected by the current sensor 15 and the voltage sensor 17 during the constant load discharge. An estimated voltage Vn, which is an estimated terminal voltage V in the discharged state, is subtracted from the open circuit voltage OCV of the battery 13 stored and stored in the NVM 25. The residual voltage drop value e ₀ , which is an amount, is stored and stored.

The outputs of the above-described current sensor 15, voltage sensor 17, and temperature sensor 19 are constantly taken into the CPU 23a of the microcomputer 23 via the I / F 21.

Next, the processing performed by the CPU 23a in accordance with the control program stored in the ROM 23c will be described with reference to the flowcharts of FIGS.

When the microcomputer 23 is started by receiving power supply from the battery 13 and the program is started, the CPU 23
First, as shown in the flowchart of the main routine in FIG. 4, a performs initial setting (step S1).

In the initial setting in step S1,
The reset of the flag of the flag area provided in the work area of the RAM 23b, the reset of the timer area to zero, the start of time counting, and the like are performed.

When the initial setting of step S1 is completed,
Next, after performing the open-circuit voltage update process (step S3) and the state-of-charge calculation process (step S5) successively, it is checked whether or not the power supply from the battery 13 has been cut off (step S7). If not (N in step S7),
Returning to step S3, if the connection is cut off (Y in step S7), a termination process is performed (step S9), and a series of processes is terminated.

In the open-circuit voltage updating process in step S3, as shown in the flowchart of the subroutine in FIG. 5, the timer value T in the timer area of the RAM 23b is set to a predetermined time necessary for eliminating polarization from the maximum polarization occurrence state. Th is checked to see if it exceeds Th (step S3).
a) If the predetermined time Th has not been exceeded (step S)
3A, N), the open-circuit voltage updating process ends, and the process returns to the main routine of FIG.
a), the A / D conversion value of the terminal voltage V of the battery 13 detected by the voltage sensor 17 is obtained from the I / F 21 (step S3b), and the temperature h of the engine room (not shown) detected by the temperature sensor 19 is obtained. A / D conversion value of I / F2
1 (step S3c).

[0095] Subsequently, stored in NVM25, the open circuit voltage OCV of the stored battery 13, the open circuit voltage OCV is stored, the temperature h ₁ of the battery 13 itself or periphery of the stored time, steps S3b and Step S3c
Is updated to the A / D conversion value of the terminal voltage V of the battery 13 and the temperature h of the engine room acquired in step (step S3d),
After setting the flag F in the equilibrium state flag area of the RAM 23b to "1" (step S3e), the open circuit voltage updating process is ended, and the process returns to the main routine of FIG.

In the state-of-charge calculation process of step S5, as shown in the flowchart of the subroutine in FIG. 6, it is confirmed whether or not the state of switches other than the starter switch has changed from off to on (step S5a). If not (N in step S5a), the process proceeds to step S5f, which will be described later.
a), the discharge current I of the battery 13 detected by the current sensor 15 obtained as an A / D conversion value from the I / F 21
Is 0A (ampere) (step S5b).

If the discharge current I of the battery 13 is not 0 A (ampere) (N in step S5b), the RAM 23
b, the time count in the timer area is terminated, and the timer value T is reset to zero (step S5).
c) After the flag F in the equilibrium state flag area is set to “0” (step S5d), the charge state calculation process is terminated and the process returns to the main routine of FIG. 4, and the discharge current I of the battery 13 is 0 A (ampere). ) (Y in step S5b), it is determined whether or not the starter switch has been turned on (step S5e).

If the starter switch has not been turned on (N in step S5e), the charge state calculation process is terminated and the process returns to the main routine of FIG. 4. If the starter switch has been turned on (Y in step S5e), it will be described later. Proceed to step S5j.

On the other hand, when the state of the switches other than the starter switch has not transitioned from off to on in step S5a, the process proceeds to step S5f where the state of the switches other than the starter switch has transitioned from on to off. And if not migrated (step S
If N (5f), the process proceeds to step S5h, which will be described later. If the process proceeds (Y in step S5f), a time count in the timer area of the RAM 23b is started (step S5g). Return to the main routine.

If the state of the switches other than the starter switch has not transitioned from on to off in step S5f, the process proceeds to step S5h where it is confirmed whether or not the starter switch has been turned on (step S5).
h) If it is not turned on (N in step S5h), the charging state calculation process is terminated and the process returns to the main routine of FIG. 4. If it is turned on (Y in step S5h), the process proceeds to step S5j.

In step S5j, which proceeds when the starter switch is turned on (Y) in steps S5e and S5h, as shown in the flowchart of FIG. 7, the current sensor obtained as an A / D conversion value from the I / F 21 is used. The detected discharge current I of the battery 13 is 25
After reaching 0 A (ampere), it is checked whether or not it has started decreasing from 250 A (ampere).

If the discharge current I of the battery 13 has not started to decrease from 250 A (ampere) after reaching 250 A (ampere) (N in step S 5 j), step S 5 j is repeated until the discharge current I becomes 250 A (ampere). ), The current sensor 15 starts to decrease from 250 A (ampere) (Y in step S5j).
The A / D conversion value of the discharge current I of the battery 13 detected by the voltage sensor 17 and the A / D conversion value of the terminal voltage V of the battery 13 detected by the voltage sensor 17 are acquired as a pair from the I / F 21 (step S5k). Then, it is confirmed whether or not the obtained discharge current I of the battery 13 detected by the current sensor 15 has decreased to 35 A (ampere) (step S5m).

If the discharge current I of the battery 13 has not decreased to 35 A (ampere) (N in step S5m), the process returns to step S5k, and if it has decreased (Y in step S5m), Step S5
k, a plurality of sets of batteries 13 obtained in pairs
Using the A / D conversion value of the terminal voltage V and the discharge current I of
A correlation coefficient r for confirming the correlation of the data is calculated, and it is confirmed whether or not the value is within an allowable range of -0.9 ≧ r ≧ −1.0 (step S5n).

When the correlation coefficient r is within the allowable range and the correlation is O
If it is K (Y in step S5n), the process proceeds to step S5t described later. If the correlation coefficient r is not within the allowable range and the correlation is not OK (N in step S5n), the current sensor acquired in step S5k After discarding the pair of A / D conversion values of the discharge current I of the battery 13 detected by the battery 15 and the terminal voltage V of the battery 13 detected by the voltage sensor 17 (step S5p), the flag F in the equilibrium state flag area is discarded.
Is determined to be "0" (step S5r).

When the flag F is "0" (Y in step S5r), the charge state calculation process is terminated and the process returns to the main routine of FIG. 4. When the flag F is not "0" (N in step S5r), After setting the flag F to "0" (step S5s), the charge state calculation process is terminated, and the process returns to the main routine of FIG.

In step S5n, the correlation coefficient r
Is within the allowable range and the correlation is OK (Y), in step S5t, the discharge current I of the battery 13 detected by the current sensor 15 and the discharge current I of the battery 13 detected by the voltage sensor 17 acquired in step S5k. The least squares method is applied to the pair of the A / D conversion value with the terminal voltage V to determine a linear voltage-current characteristic equation V = aI + b. A virtual current value Is =-which shows a linear characteristic with respect to the capacitance.
10A (ampere) is substituted into the voltage-current characteristic equation V = aI + b calculated in step S5t, and the estimated voltage Vn
Is estimated (step S5v).

At the same time, the A / D conversion value of the temperature h of the engine room (not shown) detected by the temperature sensor 19 is obtained from the I / F 21 as the battery 13 itself or the surrounding temperature h ₂ at the time when the estimated voltage Vn is estimated. After that (step S5w), it is confirmed whether or not the flag F in the equilibrium state flag area is “0” (step S5x).

If the flag F is "0" (step
(Y in S5x), the process proceeds to step S5B described later, and “0”
If not (N in step S5x), the classification is NVM25.
From the stored and stored open circuit voltage OCV, step S5
The residual voltage drop value by subtracting the estimated voltage Vn estimated by v
e₀Is obtained (step S5y), stored in the NVM 27, and recorded.
Remaining residual voltage drop value e₀In step S5y
Remaining voltage drop e ₀(Step S5z),
Remaining voltage drop value e of the updated NVM 27₀Step
The estimated voltage Vn estimated in step S5v is added, and the corrected
After obtaining the constant voltage Vn '(step S5A), it will be described later.
Proceed to step S5D.

When the flag F in the equilibrium state flag area is "0" in step S5x (Y), in step S5B, the temperature of the battery 13 or the surrounding temperature at the time when the estimated voltage Vn obtained in step S5v is estimated. and h _2, stored in NVM25, stored, stored in the open-circuit voltage OCV is NVM25 of the battery 13, based on the temperature h ₁ of the battery 13 itself or near the time the stored, are stored in the ROM23c The residual voltage drop value e ₀ stored and stored in the NVM 27 is corrected by the coefficient of the correction data, and the corrected residual voltage drop value e ₀ '.
Then, the corrected residual voltage drop value e ₀ ′ is added to the estimated voltage Vn obtained in step S5v to obtain a corrected estimated voltage Vn ′ (step S5C), and then the process proceeds to step S5D.

Step S5A and step S5C, in which the process proceeds after obtaining the corrected estimated voltage Vn '
In 5D, the corrected estimated voltage Vn ′ obtained in step S5A or step S5C is calculated by a voltage ratio calculation formula: SOC = {(Vn′−Ve) / (Vs−Ve)} × 10
0 (%) or a calculation formula based on the power ratio, SOC = {[(Vn ′ + Ve) / 2] × [(Vn′−Ve) / (Vs−Ve)] × Ah} / ｛[(Vs + Ve) / 2 × Ah｝ × 100 (%) = {(Vn ′ ² −Ve ² ) / (Vs ² −Ve ² )} × 100 (%) (where Vs is the open circuit voltage at full charge, and Ve is the end of discharge) (The open circuit voltage at the time) to obtain the state of charge SOC of the battery 13.

Subsequently, the flag F in the equilibrium state flag area
Is "0" (step S5E),
If it is “0” (Y in step S5E), the charge state calculation process is terminated and the process returns to the main routine of FIG. 4. If it is not “0” (N in step S5E), the equilibrium state flag F is set to “0”. 0 ”(step S5
F), the charge state calculation process ends, and the process returns to the main routine of FIG.

As is apparent from the above description, in the battery capacity computing device 1 of the present embodiment, step S5t in the flowchart of FIG. 7 is a process corresponding to the characteristic determining means 23A in the claims. Step S5v in FIG. 7 corresponds to the processing corresponding to the estimated voltage estimating means 23B in the claims, and step S5j in FIG.
Is a process corresponding to the residual voltage drop value determining means 23D in the claims.

Further, in the battery capacity computing device 1 of the present embodiment, step S3a in the flowchart of FIG.
Is a process corresponding to the equilibrium state determining means 23C in the claims. Step S3d in FIG. 5 is a process corresponding to the open circuit voltage updating means 23E in the claims, and FIG. Step S5B in the middle is processing corresponding to the correcting means 23F in the claims.

Further, in the battery capacity calculation device 1 of the present embodiment, the current sensor 15 and the step S5j in FIG.
This constitutes a discharge current decrease start detecting means A in the claims, and comprises a current sensor 15 and a step S in FIG.
5m constitutes a discharge current drop detecting means C in the claims, and the voltage sensor 17 and step S3b in FIG. 5 constitute an equilibrium terminal voltage measuring means B in the claims. I have.

In the battery capacity calculation device 1 of the present embodiment, the discharge current I of the battery 13 is set to 250 A
(Amps) corresponds to a predetermined large current value in the claims, and 35 A (Amps) corresponds to a target current value in the claims.

Next, the operation (operation) of the battery capacity computing device 1 of the present embodiment configured as described above will be described.

First, a state in which electrical components (loads) other than the motor generator 5 of the hybrid vehicle are operating, or the motor generator 5 is operating so as to function as a motor, and the battery 13 is discharging accordingly.
Alternatively, when the motor generator 5 is operating so as to function as a generator and the battery 13 is charging accordingly, the open circuit voltage OCV stored and stored in the NVM 25 and the open circuit voltage OCV Is N
Stored in VM25, updates and stored time of the battery 13 itself or periphery of the temperature h _1, stored in NVM27, update residual voltage drop value e ₀ stored are all done without also estimated voltage Vn , And the calculation and update of the state of charge SOC using this are not performed.

Next, when the starter switch is turned on,
The motor generator 5 of the hybrid vehicle operates so as to function as a starter motor.
Performs a constant load discharge at a predetermined large current value exceeding 250 A (ampere), the current sensor 15 and the voltage are maintained until the discharge current I of the battery 13 in the discharge decreases to the target current value of 35 A (ampere). If the discharge current I and the terminal voltage V of the battery 13 detected by the sensor 17 are periodically collected as a pair and satisfy a certain correlation, the least square method is applied to them. Thus, a linear voltage-current characteristic equation V =
aI + b is calculated, and the estimated voltage V in the constant current discharge is calculated.
The estimated voltage Vn is estimated by substituting the virtual current value Is = −10 A (ampere) in which n shows a linear characteristic with respect to the capacity of the battery 13 into this voltage-current characteristic equation V = aI + b. Is done.

Then, when the estimated voltage Vn is estimated,
The temperature h of the battery 13 or the surroundings h _TwoAnd to NVM25
The stored and stored open circuit voltage OC of the battery 13
Battery 13 when V is stored and stored in NVM 25
The temperature of itself or its surroundings h₁And if there is a difference,
And the remaining voltage drop value stored and stored in the NVM 27
e₀Is compensated for temperature compensation and this compensated compensation
Residual voltage drop e₀′ To the previously estimated voltage V
n to obtain the corrected estimated voltage Vn ′.
Then, the corrected estimated voltage Vn ′ is calculated based on the voltage ratio or the power ratio.
By substituting into one of the calculation formulas, the
The state of charge SOC is calculated, and the result is displayed or displayed on the capacity tube.
Provided as management data.

In this case, in order to obtain a voltage-current characteristic equation V = aI + b of the battery 13 used for estimating the estimated voltage Vn, the discharge current I and the terminal The voltage V is 250 A (amperes), which is collected at the time of discharging to the motor generator 5 functioning as a cell motor which is the largest load in the hybrid vehicle, and the electric power of the battery 13 is simultaneously supplied to other loads. It is collected in a state where a discharge current I exceeding 35 A (ampere) that does not reach even if supplied is flowing.

For this reason, even if the power of the battery 13 is simultaneously supplied to loads other than the motor generator 5 and a voltage drop due to the discharge-side polarization occurs, the remaining polarization at the end of the discharge to the motor generator 5 is reduced. The actual state of charge SOC of the battery 13 can be accurately calculated by adding the residual voltage drop value e ₀ obtained as the residual voltage drop due to the influence to the estimated voltage Vn.

In the battery capacity computing device 1 of the present embodiment, the battery 1 is turned on when the starter switch is turned on.
3 has performed a constant load discharge exceeding 250 A (amperes), at a stage before the start of the discharge, exceeding the predetermined time Th required for eliminating polarization from the maximum polarization generation state, and
If the battery 3 has not been charged / discharged, it is assumed that the voltage fluctuation (voltage rise or voltage drop) due to polarization generated when the battery 13 was charged / discharged last time is completely eliminated and the battery 13 is in an equilibrium state. The open circuit voltage OCV of the battery 13 stored and stored in the NVM 25 is updated to the terminal voltage V of the battery 13 detected at this time.

For this reason, even if the open circuit voltage OCV fluctuates due to a change in the capacity of the battery 13, the open circuit voltage OCV stored and stored in the NVM 25 is updated to the latest value every time the battery 13 is in an equilibrium state. Thus, the calculation accuracy of the state of charge SOC of the battery 13 can be kept high.

Similarly, in the battery capacity calculation device 1 of the present embodiment, when the battery 13 is discharged from the motor generator 5 functioning as a starter motor from a state where the battery 13 is in an equilibrium state, the battery 13 is stored and stored in the NVM 27. Remaining voltage drop value e _{0 of the} battery 13
Is the open circuit voltage O of the NVM 25 updated before the start of the discharge.
It is updated to the latest remaining voltage drop value e ₀ obtained by subtracting the estimated voltage Vn estimated after the discharge from the CV.

[0125] Therefore, even if the variation remains voltage drop e ₀ with the change in state of the battery 13, each time the battery 13 is in equilibrium, stored in NVM27, the residual voltage drop value e ₀ stored By updating to the latest value, the calculation accuracy of the state of charge SOC of the battery 13 can be kept high.

Further, in the battery capacity calculating device 1 of the present embodiment, the battery 13 itself or the surrounding temperature h ₁ at the time when the open circuit voltage OCV is stored and stored in the NVM 25.
And the temperature h ₂ of the battery 13 or the surroundings at the time of estimation of the estimated voltage Vn is different, a correction for temperature compensation according to the difference is performed on the remaining voltage drop value e ₀ , Since the corrected residual voltage drop value e ₀ ′ is used to calculate the state of charge SOC of the battery 13 by adding to the Vn, the time when the residual voltage drop value e ₀ is obtained and the remaining voltage The drop value e ₀ is calculated as the estimated voltage Vn.
At the point of time when the state of charge SOC of the battery 13 is calculated by adding to the value of the battery 13, even if the temperature of the battery 13 itself or the surrounding temperature h that changes the value of the open circuit voltage OCV has occurred, 13 can be accurately calculated.

By the way, the above-described embodiment employed in this embodiment
Configuration and for the temperature compensation of the residual voltage drop value e _0, some or all of the open circuit voltage OCV and (or) configuration for updating the residual voltage drop value e _0, the relationship between the accuracy required May be omitted as long as there is no problem.

Further, in order to obtain a voltage-current characteristic equation V = aI + b of the battery 13 used for estimating the estimated voltage Vn, a period in which the discharge current I of the battery 13 and the terminal voltage V are periodically collected as a pair When the battery 13 performs a constant load discharge exceeding 250 A (ampere) as in the battery capacity calculation device 1 of the present embodiment, the discharge current I decreases from 250 A (ampere) to 35 A (ampere). However, the present invention is not limited to this.

However, in general, the voltage-current characteristics at the time of discharging of the battery 13 differ between when the discharging current I increases and when the discharging current I decreases, as shown in the graph of FIG. When the discharge current I and the terminal voltage V when performing a constant load discharge exceeding
As shown in the graph of FIG. 9, the pace at which the voltage drop due to the polarization generated in the battery 13 due to the discharge is eliminated with the decrease in the discharge current I is delayed from the pace at which the voltage drop occurs with the increase in the discharge current I. When the discharge current I decreases, the terminal voltage V becomes lower with respect to the discharge current I than when the discharge current I increases.

Further, when the discharge of the battery 13 is started in a state where the voltage rise or the voltage drop due to the previous charge / discharge remains, as shown in a general trend in the graph of FIG. Is different from the voltage-current characteristic during the increase of the discharge current I when the discharge is started from the equilibrium state described above with reference to the graph of FIG.

Therefore, the voltage-current characteristics of the battery 13 do not become the same during the increase and the decrease of the discharge current I, and the voltage-current characteristics during the increase of the discharge current I are the values before the start of the discharge. Considering that the battery 13 differs depending on whether or not the battery 13 is in an equilibrium state, at least the battery capacity calculation of the present embodiment is performed unless a condition that the characteristic difference affects only a very small error is secured. As in the device 1, the discharge current I
Battery 1 collected periodically only while the battery is decreasing
It is preferable to obtain the voltage-current characteristic expression V = aI + b of the battery 13 using only the discharge current I and the terminal voltage V of the battery 3.

In the battery capacity computing device 1 of the present embodiment, the open circuit voltage OCV of the battery 13 stored and stored in the NVM 25 corresponds to the voltage-current characteristic line during the increase of the discharge current I in FIG. , A point on the discharge current I = 0 A (ampere).
The estimated voltage Vn estimated from the voltage-current characteristics of the battery 13 obtained using only the discharge current I and the terminal voltage V of the battery 13 collected during the time when the voltage decreases from A (ampere) to 35 A (ampere) is shown in FIG. 8, the virtual current value Is = −10 of the voltage-current characteristic line while the discharge current I is decreasing.
A point on A (Amperes) will be indicated.

In the present embodiment, the voltage-current characteristic of the battery 13 at the time of constant load discharge is approximated to the first-order voltage-current characteristic equation V = aI + b. Considering the influence of the characteristics, instead of the primary voltage-current characteristic equation V = aI + b, as shown in FIG.
V = a obtained from the pair of the discharge current I and the terminal voltage V of the battery 13 at the time of constant load discharge by the least square method.
It may be approximated to a quadratic curve equation of I ² + bI + c.

In this case, the approximate curve expression V = aI ² + bI + c is used to calculate the virtual current value Is = −10.
By substituting A (ampere), the estimated voltage Vn is estimated, the latest remaining voltage drop value e ₀ is obtained and updated using the estimated estimated voltage Vn, or the estimated estimated voltage Vn is estimated.
Is added to the remaining voltage drop value e ₀ to calculate the open circuit voltage OCV of the battery 13.

As described above, if the voltage-current characteristic of the battery 13 is represented by a second-order approximate curve equation, the discharge current with respect to the pace of increase and decrease of the voltage drop of the terminal voltage V generated in the battery 13 due to the polarization caused by the discharge. The slow pace of increase and decrease of the current I is more accurately reflected than the primary voltage-current characteristic equation V = aI + b, and this approximate curve equation V = aI ² + bI + c
And the accuracy of the open circuit voltage OCV calculated using the estimated voltage Vn,
This is advantageous because it can be further increased.

Further, in the present embodiment, the discharge current I and the terminal voltage V of the battery 13 at the time of the constant load discharge exceeding 250 A (ampere) during the operation of the motor generator 5 which consumes the most power by itself are used. Thus, the voltage-current characteristic expression V = aI + b including the influence of the polarization was determined, but at least a current value sufficient to eliminate the charging-side polarization generated in the battery 13 immediately before the discharge, Using the discharge current I and the terminal voltage V of the battery 13 associated with the operation of the load other than the motor generator 5 such that the maximum value of the discharge current does not reach 250 A (ampere), the voltage-current including the influence of polarization is used. Characteristic equation V = aI + b
And two approximate curve expressions M1 and M of the above-mentioned VI characteristic.
2 may be determined.

[0137]

As described above, according to the battery capacity calculation method of the present invention, the terminal voltage and the discharge current of the battery for supplying power to the vehicle load are periodically measured. A voltage-current characteristic indicating a correlation between the terminal voltage and the discharge current is obtained, and an estimated voltage which is an estimated terminal voltage in a constant load discharge state of the battery is estimated using the voltage-current characteristic. In calculating the charge capacity of the battery using the voltage, the discharge current of the constant load discharge by the battery in an equilibrium state is at least a current sufficient to eliminate the charge-side polarization generated in the battery immediately before the discharge. A value of the estimated voltage of the battery at the time of constant load discharge with the predetermined large current value, estimated using the voltage-current characteristic while the value is decreasing from the value, and a value of the estimated voltage. The difference between the value of the open circuit voltage, which is the terminal voltage of the battery in an equilibrium state before the start of the constant load discharge, used to estimate the residual voltage drop due to the residual polarization at the end of the battery discharge It is determined in advance as a residual voltage drop value which is an amount, and thereafter, every time the battery performs constant load discharge at a current value sufficient to eliminate at least the charging side polarization generated in the battery immediately before discharging. From the battery terminal voltage and the discharge current measured periodically during the constant load discharge,
A current characteristic is obtained, a current estimated voltage of the battery is estimated using the voltage-current characteristic, and the remaining voltage drop value is added to the estimated value of the current estimated voltage of the battery. The current charge capacity of the battery is calculated.

Therefore, the terminal voltage of the battery periodically measured during the constant load discharge together with the discharge current includes a voltage drop due to the discharge, and the voltage-current characteristics of the battery obtained by using this terminal voltage, Even if the current estimated voltage of the battery estimated from the voltage-current characteristics reflects the voltage drop due to discharge, the maximum load to the vehicle load is equal to the voltage drop component reflected in the estimated voltage. The residual voltage drop value, which is the residual voltage drop amount due to the effect of the residual polarization at the end of the constant load discharge performed by the battery with the predetermined large current value corresponding to the supply power value, is added to the current estimated voltage value of the battery. By doing so, the voltage drop component reflected in the estimated voltage is offset by the residual voltage drop value,
The state of charge of the battery can be accurately calculated.

Further, according to the battery capacity calculation method of the present invention described in claim 2, in the battery capacity calculation method of the present invention described in claim 1, the value of the terminal voltage of the battery in an equilibrium state is measured in advance. The measured value is set to the value of the open-circuit voltage, and after the setting of the open-circuit voltage, the battery in an equilibrium state is charged with at least the charge-side polarization generated in the battery immediately before discharging. When performing a constant load discharge with a current value sufficient to eliminate, the discharge current of the constant load discharge is periodically measured while decreasing from the maximum current value, from the terminal voltage of the battery and the discharge current, The voltage-current characteristics are obtained, and by using the voltage-current characteristics,
From the equilibrium state, at least estimated the voltage of the battery at the time of constant load discharge with a current value sufficient to eliminate the charging side polarization that has occurred in the battery immediately before discharging, from the estimated equilibrium state The value of the estimated voltage of the battery at the time of constant load discharge with a current value sufficient to eliminate at least the charge-side polarization that has occurred in the battery immediately before the discharge is determined by the value of the set open circuit voltage. , The residual voltage drop value was obtained in advance.

Therefore, in the battery capacity calculation method according to the first aspect of the present invention, the battery in an equilibrium state is:
At least when a constant load discharge with a current value sufficient to eliminate the charging-side polarization that has occurred in the battery immediately before discharging is performed, the value of the open circuit voltage is obtained and set, and the obtained Since the residual voltage drop value is obtained by subtracting the estimated voltage to be estimated later from the open circuit voltage, it is not necessary to recognize the open circuit voltage or the residual voltage drop value in advance and set it by itself. be able to.

Further, according to the battery capacity calculation method of the present invention described in claim 3, in the battery capacity calculation method of the present invention described in claim 2, the open circuit is set every time the battery is brought into an equilibrium state. The value of the voltage is updated and set to the value of the terminal voltage of the battery measured in the equilibrium state.

For this reason, in the battery capacity calculation method according to the present invention, the value of the open circuit voltage is updated and set to the latest one each time the battery is in an equilibrium state.
Regarding the remaining voltage drop value, whenever the value of the open circuit voltage is updated to the latest value, the latest value can be obtained in advance, and the remaining voltage drop value is added to the current estimated voltage of the battery. Can be always accurately calculated in response to a change in the open circuit voltage due to a change in the state of charge of the battery or the like.

According to the battery capacity calculating method of the present invention described in claim 4, in the battery capacity calculating method of the present invention described in claim 1, 2, or 3, the battery is charged at least immediately before discharging. Each time a constant load discharge with a current value sufficient to eliminate the charging side polarization that occurred in the battery was performed, the discharge current during the constant load discharge was periodically measured while decreasing from the maximum current value. From the terminal voltage of the battery and the discharge current, the voltage-current characteristics are determined,
The current estimated voltage of the battery is estimated using the voltage-current characteristics.

Therefore, in the battery capacity calculation method according to the present invention, the increase or decrease in the voltage drop due to the discharge side polarization is not affected by the increase or decrease in the discharge current in the constant load discharge. Due to the delay, the voltage-current characteristics of the battery are different between when the discharge current is increasing and when the discharge current is decreasing, and the voltage rise and the voltage drop of the terminal voltage of the battery due to the polarization generated by the previous charge / discharge remain. In this state, even if a constant load discharge of the battery is performed with a current value sufficient to eliminate at least the charge-side polarization that has occurred in the battery immediately before discharging, the characteristics are always the same without being affected by them. The current estimated voltage of the battery is estimated using the appearing voltage-current characteristic part, and the calculation of the state of charge of the battery is performed based on the polarization generated by the previous charge / discharge. It can be performed with high accuracy without being affected by the voltage fluctuation due.

Further, according to the battery capacity calculating method of the present invention described in claim 5, in the battery capacity calculating method of the present invention described in claim 1, 2, 3 or 4, at least immediately before discharging the battery, A current value sufficient to eliminate the generated charging-side polarization is set to a predetermined large current value required at the time of starting the cell motor of the vehicle, and the discharge current value of the battery decreases from the predetermined large current value. From the start, the cycle is lower than the predetermined large current value and equal to or greater than the maximum discharge current value when the load of the vehicle other than the self-motor is driven, and is reduced to the target current value. The voltage-current characteristic used to estimate an estimated voltage of the battery at the time of constant load discharge with the predetermined large current value from a terminal voltage and a discharge current of the battery that are measured in a specific manner. It was to ask.

Therefore, in the battery capacity calculation method according to the present invention, even if the load of the vehicle other than the cell motor is still driven,
A battery terminal that reflects only a residual component of a voltage drop due to discharge-side polarization generated by performing a discharge with a predetermined large current value, excluding a component that is eliminated by a decrease in a discharge current to a target current value. From the voltage and the discharge current, a voltage-current characteristic excluding the influence of power supply to the load of the vehicle other than the self-motor is obtained, and the estimated voltage is obtained, so that the state of charge of the battery can be accurately calculated.

Further, according to the battery capacity calculation method of the present invention described in claim 6, claim 1, 2, 3, 4, or 5 is provided.
In the battery capacity calculation method according to the present invention, the estimated voltage of the battery at the time of constant load discharge at least with a current value sufficient to eliminate the charging side polarization generated in the battery immediately before discharging is estimated. Then, it is checked whether there is a difference between the ambient temperature of the battery at the time of the estimation and the ambient temperature of the battery at the time of obtaining the open circuit voltage, and if there is a difference, according to the temperature difference, The remaining voltage drop value is corrected, and the current charge capacity of the battery is calculated using the corrected remaining voltage drop value.

For this reason, in the battery capacity calculation method according to the present invention, the ambient temperature of the battery changes to change the capacity of the battery. Even if the open circuit voltage of the battery changes with respect to the open circuit voltage used when the residual voltage drop value is obtained in advance, temperature compensation is performed by correcting the residual voltage drop value, and the temperature is compensated according to the current battery peripheral temperature. The current charge capacity of the battery can be accurately calculated.

Further, according to the battery capacity calculation device of the present invention, the charge-side polarization generated in the battery for supplying power to the vehicle load at least immediately before discharging is eliminated. During a constant load discharge with a sufficient current value, the terminal voltage and the discharge current of the battery during the constant load discharge are periodically measured to obtain a voltage-current characteristic showing a correlation between the terminal voltage and the discharge current. Estimating an estimated voltage that is an estimated terminal voltage in a constant load discharge state of the battery using the voltage-current characteristics,
In the battery capacity calculation device that calculates the charge capacity of the battery using the estimated voltage, the discharge current of the constant load discharge by the battery in the equilibrium state eliminates at least the charge-side polarization generated in the battery immediately before the discharge. The current value sufficient to eliminate the charging-side polarization that has occurred in the battery at least immediately before discharging, while the current value is decreasing from the current value sufficient to perform the charging. The value of the estimated voltage of the battery at the time of constant load discharge, and the value of the open circuit voltage that is the terminal voltage of the battery in an equilibrium state before the start of the constant load discharge used to estimate the value of the estimated voltage. A residual voltage drop value storage means for storing a difference value of the residual voltage drop value as a residual voltage drop value which is a residual voltage drop amount due to the influence of residual polarization at the end of discharging of the battery. Ri, the residual voltage drop value stored in the residual voltage drop value storing means, by adding to the value of the estimated voltage of the battery that the estimated and configured for calculating a current charge capacity of the battery.

For this reason, the terminal voltage of the battery periodically measured during the constant load discharge together with the discharge current includes the voltage drop due to the discharge, and the voltage-current characteristics of the battery obtained by using this terminal voltage, Even if the current estimated voltage of the battery estimated from this voltage-current characteristic reflects the voltage drop due to discharge, the voltage is equal to the voltage drop component reflected in the estimated voltage, and at least immediately before the discharge. The residual voltage drop amount, which is the residual voltage drop amount due to the residual polarization effect at the end of the constant load discharge performed by the battery with a current value sufficient to eliminate the charging-side polarization that has occurred, is stored in the residual voltage drop value storage means. The residual voltage drop value
By adding to the value of the current estimated voltage of the battery, the voltage drop component reflected in the estimated voltage is canceled by the remaining voltage drop value, and the state of charge of the battery can be accurately calculated.

According to the battery capacity calculating device of the present invention described in claim 8, in the battery capacity calculating device of the present invention described in claim 7, at least the charging side generated in the battery immediately before the discharging. Discharge current decrease start detecting means for detecting that the discharge current of the battery has started to decrease from the maximum current value during constant load discharge of the battery with a current value sufficient to eliminate the polarization; After the discharge current decrease start detecting means detects that the voltage has started to decrease from the maximum current value, the characteristic determining means for obtaining the voltage-current characteristic from the battery terminal voltage and the discharge current measured periodically. And a voltage sufficient to eliminate at least charging-side polarization generated in the battery immediately before discharging, using the voltage-current characteristic obtained by the characteristic determining means. An estimated voltage estimating means for estimating an estimated voltage of the battery at the time of constant load discharge based on the value, wherein the estimated voltage value of the battery estimated by the estimated voltage estimating means is stored in the remaining voltage drop value storing means. By adding the residual voltage drop value stored in
The current charge capacity of the battery is calculated.

Therefore, in the battery capacity calculating device according to the present invention, the increase or decrease of the voltage drop due to the discharge side polarization occurs later than the increase or decrease of the discharge current in the constant load discharge. In addition, when the voltage-current characteristics of the battery are different between when the discharge current is increasing and when the discharge current is decreasing, and when the voltage rise and the voltage drop of the battery terminal voltage due to the polarization generated by the previous charge / discharge remain, Even when a constant load discharge of the battery is performed by the large current value of the above, the voltage-current characteristics that always appear as the same characteristics without being affected by them are determined by the characteristic determining means, and the characteristic determining means determines the voltage-current characteristics. The state of charge of the battery is calculated using the current estimated voltage of the battery estimated by the estimated voltage estimating means using the voltage-current characteristics, so that the state of charge of the battery is calculated. And it can be accurately performed without being affected by the voltage fluctuation due to the polarization generated by the previous charge and discharge.

Further, according to the battery capacity calculating device of the present invention described in claim 9, in the battery capacity calculating device of the present invention described in claim 8, the open circuit voltage value for storing the value of the open circuit voltage Storage means; equilibrium state determination means for determining whether or not the battery is in an equilibrium state; and a battery generated at least immediately before discharging from the battery determined to be in an equilibrium state by the equilibrium state determination means. During constant load discharge with a current value sufficient to eliminate the charging-side polarization, the estimated voltage value of the battery estimated by the estimated voltage estimation means is stored in the open circuit voltage value storage means. Remaining voltage drop value calculating means for subtracting from the value of the open circuit voltage to obtain the remaining voltage drop value, wherein the remaining voltage drop value storage means stores the remaining voltage drop value. Detecting means is configured to store the residual voltage drop value calculated.

For this reason, in the battery capacity calculating apparatus according to the present invention, the battery determined to be in the equilibrium state by the equilibrium state determining means is charged at least on the charge side polarization generated in the battery immediately before the discharging. When a constant load discharge is performed with a current value sufficient to eliminate the residual voltage drop value stored in the residual voltage drop value storage means using the value of the estimated voltage estimated by the estimated voltage estimation means, the residual voltage It is possible to eliminate the necessity of recognizing the residual voltage drop value in advance and setting it by itself as determined by the drop value determining means.

According to the battery capacity calculation device of the present invention described in claim 10, in the battery capacity calculation device of the present invention described in claim 9, the equilibrium state determination means determines that the battery is in an equilibrium state. The terminal voltage measuring means for measuring the terminal voltage of the battery in the closed state, and the battery having the terminal voltage measuring means for measuring the open circuit voltage value stored in the open circuit voltage value storage means. And an open circuit voltage updating means for updating the terminal voltage value to the terminal voltage value.

Therefore, in the battery capacity calculating device according to the ninth aspect of the present invention, each time the equilibrium state determining means determines that the battery is in the equilibrium state, the open circuit voltage value stored in the open circuit voltage value storing means is stored. The open circuit voltage stored in the open circuit voltage value storage means so that the circuit voltage value is updated by the open circuit voltage update means to the battery terminal voltage value measured by the equilibrium terminal voltage measurement means. Is always updated to the latest one, and the state of charge of the battery calculated by adding the remaining voltage drop value to the current estimated voltage of the battery is changed to the fluctuation of the open circuit voltage due to changes in the state of charge of the battery. Correspondingly, calculations can always be performed accurately.

Further, according to the battery capacity calculation device of the present invention described in claim 11, in the battery capacity calculation device of the present invention described in claim 10, temperature detecting means for detecting the ambient temperature of the battery, At the time when the estimated voltage of the battery is estimated by the estimated voltage estimating means, at the time when the temperature around the battery detected by the temperature detecting means and the terminal voltage of the battery are measured by the equilibrium terminal voltage measuring means, Checking whether there is a difference from the ambient temperature of the battery detected by the temperature detecting means, and if there is a difference, according to the temperature difference, the residual voltage drop value stored in the residual voltage drop value storage means Correction means for correcting the residual voltage drop value, when the correction means has corrected the residual voltage drop value, the corrected residual voltage drop value, By serial estimating voltage estimating means it is added to the value of the estimated voltage of the battery estimated and configured for calculating a current charge capacity of the battery.

For this reason, in the battery capacity calculating device according to the present invention, the temperature of the battery detected by the temperature detecting means changes and the capacity of the battery changes. Even if the circuit voltage changes with respect to the open circuit voltage stored in the open circuit voltage value storage means, which is used when obtaining the remaining voltage drop value by the remaining voltage drop value calculating means, the remaining voltage drop is corrected by the correction means. By correcting the value, the temperature is compensated, and the current charge capacity of the battery according to the current temperature around the battery can be accurately calculated.

According to the battery capacity calculation device of the present invention described in claim 12, the claim 8, 9, 10, or 1 is provided.
In the battery capacity calculation device according to the first aspect of the invention,
At least a current value sufficient to eliminate the charge-side polarization generated in the battery immediately before discharging is a predetermined large current value required at the time of starting the cell motor of the vehicle, and the discharge current decrease start detecting means is In the constant load discharge of the battery, it is configured to detect that the discharge current of the battery has started to decrease from the predetermined large current value, and to detect that the discharge current has started to decrease from the predetermined large current value. A discharge for detecting that the discharge current of the battery detected by the discharge current decrease start detecting means has decreased to a target current value that is equal to or greater than a maximum discharge current value when a load of the vehicle other than the self-motor is driven. Current drop detecting means, wherein the characteristic determining means detects that the discharge current of the battery has started to decrease from the predetermined large current value, and starts the discharge current decrease. After the detection by the output means, the voltage-current is calculated from the terminal voltage of the battery and the discharge current which are periodically measured until the discharge current drop detection means detects that the voltage has decreased to the target current value. The configuration for obtaining characteristics was adopted.

Therefore, in the battery capacity calculating apparatus according to the present invention, even if the load of the vehicle other than the cell motor is still driven, the discharge by the predetermined large current value is performed. Of the voltage drop due to the discharge-side polarization caused by the discharge current, the discharge current decrease start detecting means detects that the discharge current of the battery has started to decrease from a predetermined large current value, and then the discharge current is reduced to the target current. Before the discharge current drop detection means detects that the battery voltage has dropped to a value, only the remaining components excluding the voltage drop eliminated by the drop in the discharge current are calculated from the battery terminal voltage and the discharge current that are purely reflected. A voltage-current characteristic and an estimated voltage, excluding the influence of the power supply to the load of the vehicle other than the cell motor, are obtained by a characteristic determining unit and an estimated voltage estimating unit, The state of charge of Tteri can be accurately calculated.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram of a battery capacity calculation device according to the present invention.

FIG. 2 is an explanatory diagram partially showing a schematic configuration of a battery capacity calculation device according to an embodiment of the present invention to which the battery capacity calculation method of the present invention is applied.

FIG. 3 is a graph showing an example of correction data of a residual voltage drop value stored in a ROM of the microcomputer of FIG. 2;

FIG. 4 is a flowchart illustrating a main routine of a process performed by a CPU according to a control program stored in a ROM of the microcomputer of FIG. 2;

FIG. 5 is a flowchart of a subroutine showing an open circuit voltage update process of FIG. 4;

FIG. 6 is a flowchart of a subroutine showing a charge state calculation process of FIG. 4;

FIG. 7 is a flowchart of a subroutine showing a charge state calculation process of FIG. 4;

FIG. 8 is a graph showing a general voltage-current characteristic difference between when the discharge current increases and when the discharge current decreases in constant load discharge performed by a battery in an equilibrium state.

FIG. 9 shows the battery of FIG.
4 is a graph showing a voltage-current characteristic difference between when the discharge current increases and when the discharge current decreases in constant load discharge.

FIG. 10 is a graph showing a general voltage-current characteristic difference between when the discharge current increases and when the discharge current decreases in a constant load discharge performed by a battery that is not in an equilibrium state.

FIG. 11 shows an example of a voltage-current characteristic of a battery expressed by a quadratic approximation obtained by applying the least squares method to a set of a predetermined number of terminal voltages and a discharge current sampled during constant current discharge of the battery. It is a graph shown.

FIG. 12 is a graph showing a correlation between a terminal voltage and a discharge time in constant current discharge of a battery.

FIG. 13 schematically shows a relationship between a set of a predetermined number of terminal voltages and discharge currents sampled during constant current discharge of a battery, and a linear voltage-current characteristic equation obtained by applying the least squares method thereto. It is a graph shown in FIG.

FIG. 14 is a graph showing a plurality of constant current discharge characteristics obtained from an estimated voltage estimated from the voltage-current characteristics shown in FIG.

FIG. 15 is a graph showing a plurality of virtual constant-current discharge characteristics obtained from an estimated voltage estimated from the voltage-current characteristics shown in FIG.

FIG. 16 is a graph in which voltage-current characteristics of a battery according to each capacity are developed on the same plane.

17 is a graph showing a relationship between a battery capacity at a virtual discharge current value showing a linear characteristic in the graph of FIG. 15 and an estimated voltage estimated from the voltage-current characteristic shown in FIG.

FIG. 18 is a graph showing the details of a voltage drop that occurs during discharging of a battery.

[Explanation of symbols]

 Reference Signs List 5 cell motor 13 battery 19 temperature detecting means 23 microcomputer 23a CPU 23b RAM 23c ROM 23A characteristic determining means 23B estimated voltage estimating means 23C equilibrium state determining means 23D residual voltage drop value determining means 23E open circuit voltage updating means 23F correcting means 25 Open circuit voltage value storage means 27 Remaining voltage drop value storage means A Discharge current decrease start detection means B Equilibrium terminal voltage measurement means C Discharge current decrease detection means

Continued on the front page (72) Inventor Hideaki Kambara 1500 Onjuku, Susono-shi, Shizuoka Prefecture F-term (reference) 2G016 CA03 CB01 CB11 CB12 CB21 CC01 CC02 CC03 CC04 CC10 CC12 CC13 CC14 CC16 CC24 CC27 CC28 CF06 5G003 BA01 DA02 EA05 FA06 GC05 5H030 AA04 AA06 AS08 FF27 FF42 FF44 FF52 5H115 PA12 PG04 PI13 PU25 SE06 TI02 TO05 TO13 TR19

Claims (12)

[Claims] 1. A terminal voltage and a discharge current of a battery for supplying power to a load of a vehicle are periodically measured to obtain a voltage-current characteristic indicating a correlation between the terminal voltage and a discharge current. Estimating an estimated voltage that is an estimated terminal voltage in a constant load discharge state of the battery using the characteristics,
In calculating the charge capacity of the battery using this estimated voltage, the discharge current of the constant load discharge by the battery in an equilibrium state is at least sufficient to eliminate the charge-side polarization generated in the battery immediately before discharging. A value of the estimated voltage of the battery at the time of constant load discharge by the predetermined large current value, which is estimated using the voltage-current characteristic while the current value is decreasing from the minimum current value. The difference between the value of the open circuit voltage, which is the terminal voltage of the battery in an equilibrium state before the start of the constant load discharge, and the residual voltage drop due to the residual polarization at the end of the battery discharge Is determined in advance as a residual voltage drop value, and thereafter, the battery has a current value sufficient to eliminate at least charge-side polarization that has occurred in the battery immediately before discharging. Each time the constant load discharge is performed, the voltage-current characteristic is obtained from the terminal voltage of the battery and the discharge current periodically measured during the constant load discharge, and the current of the battery is determined using the voltage-current characteristic. Estimated current voltage of the battery, and adding the remaining voltage drop value to the estimated current value of the battery current to calculate the current charge capacity of the battery, Battery capacity calculation method. 2. A terminal voltage value of the battery in an equilibrium state is measured in advance, and the measured value is set to the value of the open circuit voltage. When the battery performs a constant load discharge with a current value sufficient to eliminate at least the charging side polarization generated in the battery immediately before the discharge, the discharge current of the constant load discharge decreases from the maximum current value. The voltage-current characteristics are obtained from the terminal voltage and the discharge current of the battery, which are periodically measured, and using the voltage-current characteristics, the voltage-current characteristics are generated in the battery at least immediately before discharging from the equilibrium state. Estimated the estimated voltage of the battery at the time of constant load discharge by a current value sufficient to eliminate the charged side polarization, and from the estimated equilibrium state, at least the charge side generated in the battery at least immediately before discharging. polarization The value of the estimated voltage of the battery at the time of constant load discharge with a current value sufficient to eliminate
By subtracting from the set value of the open circuit voltage,
2. The battery capacity calculation method according to claim 1, wherein said remaining voltage drop value is obtained in advance. 3. The battery capacity according to claim 2, wherein the value of the open circuit voltage is updated and set to the value of the terminal voltage of the battery measured in the equilibrium state every time the battery is in the equilibrium state. Calculation method. 4. Each time the battery performs a constant load discharge with a current value sufficient to eliminate at least a charge-side polarization generated in the battery immediately before the discharge, the discharge current of the constant load discharge becomes maximum. From the terminal voltage of the battery and the discharge current, which were periodically measured while decreasing from the current value, the voltage-current characteristic was obtained, and using this voltage-current characteristic,
4. The battery capacity calculation method according to claim 1, wherein the current estimated voltage of the battery is estimated. 5. A current value sufficient to eliminate at least charging-side polarization generated in the battery immediately before discharging,
A predetermined large current value required at the time of starting the cell motor of the vehicle, and the discharge current value of the battery is lower than the predetermined large current value after the discharge current value starts decreasing from the predetermined large current value. When the load of the vehicle other than the maximum discharge current value is equal to or more than the maximum discharge current value until the target current value is reduced, the terminal voltage and the discharge current of the battery periodically measured are used as the predetermined value. 5. The battery capacity calculation method according to claim 1, wherein the voltage-current characteristic used for estimating the estimated voltage of the battery at the time of constant load discharge with a large current value is obtained. 6. Every time when estimating the estimated voltage of the battery at the time of constant load discharge with a current value sufficient to eliminate the charging-side polarization generated in the battery immediately before discharging at least, the estimated voltage at the time of the estimation is calculated. The presence or absence of a difference between the ambient temperature of the battery and the ambient temperature of the battery at the time when the open circuit voltage is obtained is checked, and if there is a difference, the residual voltage drop value is corrected according to the temperature difference. 6. The battery capacity calculation method according to claim 1, wherein the current charge capacity of the battery is calculated using the corrected remaining voltage drop value. 7. At the time of constant-load discharge of a battery that supplies power to a load of a vehicle at a constant load with a current value sufficient to eliminate at least charging-side polarization that has occurred in the battery immediately before discharging. The terminal voltage and the discharge current of the battery are periodically measured to obtain a voltage-current characteristic indicating the correlation between the terminal voltage and the discharge current, and the voltage-current characteristic is used in the constant load discharge state of the battery. In a battery capacity calculating device for estimating an estimated voltage which is an estimated terminal voltage and calculating a charge capacity of the battery using the estimated voltage, a discharge current of constant load discharge by the battery in an equilibrium state is at least immediately before discharge. Estimated from the voltage-current characteristics while the current value decreases from a current value sufficient to eliminate the charging-side polarization generated in the battery, Also used to estimate the value of the estimated voltage of the battery at the time of constant load discharge with a current value sufficient to eliminate the charging side polarization that occurred in the battery immediately before discharging, and the value of the estimated voltage. The difference between the value of the open circuit voltage, which is the terminal voltage of the battery in an equilibrium state before the start of the constant load discharge, and the residual voltage drop, which is the residual voltage drop due to the residual polarization at the end of the battery discharge, A remaining voltage drop value storage means for storing the remaining voltage drop value stored in the remaining voltage drop value storage means to the estimated voltage value of the battery, A battery capacity calculation device for calculating a current charge capacity of a battery. 8. A constant load discharge of the battery with a current value sufficient to eliminate at least a charge-side polarization generated in the battery immediately before the discharge, the discharge current of the battery starts to decrease from a maximum current value. A discharge current decrease start detecting means for detecting that the discharge current of the battery has started to decrease from a maximum current value. A characteristic determining means for determining the voltage-current characteristic from the terminal voltage and the discharge current; and a charge side generated in the battery at least immediately before discharging, using the voltage-current characteristic determined by the characteristic determining means. An estimated voltage estimating means for estimating an estimated voltage of the battery at the time of constant load discharge with a current value sufficient to eliminate the polarization. 8. The current charge capacity of the battery is calculated by adding the remaining voltage drop value stored in the remaining voltage drop value storage means to the value of the estimated voltage of the battery estimated by the stage. Battery capacity calculation device. 9. An open circuit voltage value storage means for storing the value of the open circuit voltage, an equilibrium state judgment means for judging whether the battery is in an equilibrium state, and an equilibrium state by the equilibrium state judgment means. From the battery determined to be
The value of the estimated voltage of the battery estimated by the estimated voltage estimating means at least at the time of constant load discharge at a current value sufficient to eliminate the charging-side polarization generated in the battery immediately before the discharge is determined by the open circuit voltage Remaining voltage drop value calculating means for subtracting from the value of the open circuit voltage stored in the value storing means to obtain the remaining voltage drop value, wherein the remaining voltage drop value storing means stores the residual voltage drop value. 9. The battery capacity calculation device according to claim 8, wherein the remaining voltage drop value obtained by the indexing means is stored. 10. An equilibrium terminal voltage measuring means for measuring a terminal voltage of the battery when the equilibrium state judging means judges that the battery is in an equilibrium state, and the open circuit voltage value stored in the open circuit voltage value storing means. 10. The battery capacity calculation device according to claim 9, further comprising: an open circuit voltage updating unit that updates a circuit voltage value to a value of the battery terminal voltage measured by the equilibrium terminal voltage measuring unit. 11. A temperature detecting means for detecting an ambient temperature of the battery, and at the time when the estimated voltage of the battery is estimated by the estimated voltage estimating means, an ambient temperature of the battery detected by the temperature detecting means; When the terminal voltage of the battery is measured by the terminal voltage measuring means in the equilibrium state, it is checked whether or not there is a difference from the ambient temperature of the battery detected by the temperature detecting means. Correction means for correcting the residual voltage drop value stored in the residual voltage drop value storage means, and when the residual voltage drop value has been corrected by the correction means, The current charge capacity of the battery is calculated by adding a remaining voltage drop value to a value of the estimated voltage of the battery estimated by the estimated voltage estimating means. The battery capacity calculation device according to any one of the preceding claims. 12. A current value sufficient to eliminate at least charge-side polarization generated in the battery immediately before discharging is a predetermined large current value required when starting the cell motor of the vehicle. The decrease start detecting means is configured to detect that the discharge current of the battery has started to decrease from the predetermined large current value during the constant load discharge of the battery, and to decrease from the predetermined large current value. The discharge current of the battery detected by the discharge current decrease start detecting means has started to decrease to a target current value that is equal to or greater than a maximum discharge current value when a load of the vehicle other than the cell motor is driven. Further comprising discharge current decrease detection means for detecting that the characteristic determination means,
After the discharge current decrease start detecting means detects that the discharge current of the battery has started to decrease from the predetermined large current value, until the discharge current decrease detecting means detects that the discharge current has decreased to the target current value. Between the terminal voltage of the battery and the discharge current measured periodically,
12. The battery capacity calculation device according to claim 8, wherein the current characteristic is obtained.