JP2000150003A - Method and device for charged amount calculation for hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charged amount calculating device for hybrid vehicle capable of calculating accurately the charged amount SOC(state of change) of a secondary battery. SOLUTION: This device for charged amount calculation for a hybrid vehicle is composed of a voltage sensor 8 to sense the terminal voltage V of a secondary battery, a current sensor 9 to sense the charge/discharge current value I, an Ah calculation part 22 to calculate the cumulated amperage Ah on the basis of the sensed current value I, an RSOC calculation part 23 to calculate the first charged amount on the basis of Ah, a momentary power calculation part 21 and release voltage E3 calculation part 25 to calculate the release voltages E2 and E3 of the secondary battery on the basis of the second current I and voltage V, respectively, and a CAPAH calculation part 24 to calculate the second charged amount in compliance with the release voltages E2 and E3. When the difference between the first and second charged amounts becomes over the specified value, the first charged amount is corrected on the basis of the second charged amount.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for calculating a charge amount of a driving secondary battery used in a hybrid vehicle or the like.

[0002]

A hybrid electric vehicle (hereinafter, referred to as a hybrid vehicle) which includes an internal combustion engine and an electric motor as a driving source for driving and runs by using both or one of the driving forces is known. Have been. In such a hybrid vehicle, one of the methods of calculating the state of charge (SOC) of the motor driving secondary battery is Ah, which is obtained by integrating the current during charging and discharging.
There is a method of calculating from the integrated value (= Σ (I × t): I is a current value, t is time) and the battery capacity.

However, in the above-described calculation method, if the current value I has a detection error ΔI, the errors are accumulated. The accumulated error こ の (ΔI
Xt), there is a problem that every time the charge amount SOC is calculated, the error increases and the actual charge amount SOC greatly deviates.

An object of the present invention is to provide a method and apparatus for calculating a charge amount of a hybrid vehicle, which can accurately calculate a charge amount SOC of a secondary battery.

[0005]

An embodiment of the present invention will be described with reference to FIGS. 1 and 8. FIG. (1) Explaining with reference to FIG. 8, the method of calculating the charge amount of a hybrid vehicle according to the first aspect of the present invention is as follows: (a) integrating the current value I of the secondary battery at the time of charging and discharging; A first method for calculating the charge amount of the secondary battery based on Ah = ΣI · t), (b) calculating the charge amount of the secondary battery based on the terminal voltage value E1 of the secondary battery in a no-load state (C) calculating a first open voltage E2 of the secondary battery by a power calculation based on the terminal voltage value V and the current value I of the secondary battery at the time of charging and discharging; A third calculation method for calculating the charge amount of the secondary battery based on the voltage E2,
(D) A second open circuit voltage E3 is calculated based on the terminal voltage value V, the current value I, and the internal resistance value of the secondary battery at the time of charging and discharging, and charging of the secondary battery is performed based on the second open circuit voltage E3. The above object is achieved by calculating the charge amount of the secondary battery by at least two of the fourth calculation methods for calculating the amount. (2) According to a second aspect of the present invention, in the charge amount calculation method according to the first aspect, the charge amount of the secondary battery is calculated using the first calculation method and the third calculation method. (3) According to a third aspect of the present invention, in the charge amount calculation method according to the first aspect, the charge amount of the secondary battery is calculated using the first calculation method and the fourth calculation method. (4) According to a fourth aspect of the present invention, in the charge amount calculation method according to the first aspect, the charge amount of the secondary battery is calculated using the first calculation method, the second calculation method, and the third calculation method. I do. (5) According to a fifth aspect of the present invention, in the charge amount calculation method according to the first aspect, the charge amount of the secondary battery is calculated using the first calculation method, the second calculation method, and the fourth calculation method. I do. (6) According to a sixth aspect of the present invention, a current integrated value Ah is calculated based on a charge / discharge current value I of a secondary battery, and a first charge amount of the secondary battery is calculated based on the current integrated value Ah. The method is applied to a method for calculating the charge amount of a hybrid vehicle. (A) A second charge amount is calculated based on a terminal voltage value E1 when the secondary battery is in a no-load state, and a second charge amount and a first charge amount are calculated. A first correction method for replacing the first charge amount with the second charge amount when the difference between the first charge amount and the second charge amount becomes equal to or more than a predetermined value. (B) The terminal voltage value V and the current value I during charging and discharging of the secondary battery The first open circuit voltage E2 is calculated by the power calculation based on the following equation, and the difference between the third charge amount calculated based on the first open circuit voltage E2 and the first charge amount becomes equal to or more than a predetermined value. The second correction method for replacing the first charge amount with the third charge amount, (c) the terminal voltage value V, the current value I, and the And the second open circuit voltage E3 is calculated based on the internal resistance value, and the difference between the fourth charge amount and the first charge amount calculated based on the second open circuit voltage E3 is equal to or greater than a predetermined value. The above object is achieved by correcting the first charge amount using at least two of the third correction methods, which sometimes replace the first charge amount with the fourth charge amount. (7) According to a seventh aspect of the present invention, in the charge amount calculation method according to the sixth aspect, the first charge amount is corrected using the first correction method and the second correction method. (8) According to an eighth aspect of the present invention, in the charge amount calculation method according to the sixth aspect, the first charge amount is corrected using the first correction method and the third correction method. (9) Explaining in connection with FIGS. 1 and 8, the invention of claim 9 is a current detecting means 9 for detecting a charging / discharging current value I of the secondary battery 6 and a current detecting value I of the current detecting means 9. And a first charge amount calculating means 23 for calculating a first charge amount of the secondary battery 6 based on the current integrated value Ah. The terminal voltage V of the secondary battery 6 is applied to the charge amount calculating device.
Voltage detecting means 8 for detecting the open-circuit voltage, and open-circuit calculating means 2 for calculating open-circuit voltages E2 and E3 of the secondary battery 6 based on the detected value I of the current detecting means 9 and the detected value V of the voltage detecting means 8.
A second charge amount that is calculated based on the open-circuit voltage calculation values E2 and E3 by the open-circuit voltage calculation means 21 and 25;
And a correction means for correcting the first charge amount based on the second charge amount when a difference between the first charge amount and the second charge amount becomes equal to or greater than a predetermined value. 23, 24,
The above-described object is achieved by providing the above.

In the section of the means for solving the above-mentioned problems, which explains the configuration of the present invention, the drawings of the embodiments of the present invention are used in order to make the present invention easier to understand. However, the present invention is not limited to the embodiment.

[0007]

As described above, according to the first to fifth aspects of the present invention, the charge amount of the secondary battery is calculated by using at least two of the four different calculation methods. Thereby, the amount of charge can be accurately calculated in various running patterns. According to the sixth to eighth aspects of the present invention, there are provided three types of correction methods for replacing the first charge amount with the second, third, or fourth charge amount having no influence of a cumulative error due to a current detection value error or the like. By using at least two, the influence of the accumulated error due to the current detection value error or the like on the charge amount can be reduced, and the charge amount can be accurately calculated in various traveling patterns. According to the ninth aspect of the present invention, the second charge amount obtained according to the open-circuit voltage calculation value is not affected by the accumulated error due to the current detection value error or the like. By correcting with the charge amount of 2, the influence of the accumulated error due to the current detection value error or the like on the charge amount can be reduced, and the charge amount can be accurately calculated in various running patterns.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a block diagram showing a configuration of a parallel hybrid vehicle. The rotor of the electric motor 3 is directly connected to the main shaft of the engine 2, and the driving force of the engine 2 and / or the motor 3 is transmitted to the axle 7 via the drive system 4. The operation modes of the motor 3 in the parallel hybrid vehicle include a drive mode for driving the axle 7 and a power generation mode for charging the secondary battery 6.
A rechargeable battery 6 for supplying electric power to the motor 3 in a drive mode of the vehicle itself, that is, when accelerating, traveling on a flat road, or climbing a hill.
Is in a sufficiently charged state, the motor 3 is operated in the drive mode and the vehicle runs with both driving forces of the engine 2 and the motor 3.

However, when the state of charge of the secondary battery 6 is low, the motor 3 is operated in the power generation mode to run by the driving force of the engine 2 and to rotate the rotor of the motor 3 by the driving force of the engine 2. Then, the electric power is generated by the motor 3 to charge the secondary battery 6. The inverter 5 is a secondary battery 6
The DC power from the motor 3 is converted into AC power and supplied to the motor 3, and the AC power from the motor 3 is converted into DC power and supplied to the secondary battery 6 in the power generation mode.

On the other hand, when the vehicle is in a braking mode, that is, at the time of deceleration or downhill, the engine 2 and the motor 3 are driven by the rotational force of the wheels via the drive system 4. At this time, the motor 3 is operated in the power generation mode to absorb the regenerative energy and charge the secondary battery 6. The controller 1 includes a microcomputer and its peripheral parts, and includes a voltage sensor 8 for detecting a terminal voltage value V of the secondary battery 6, a current sensor 9 for detecting a current value I during charging and discharging, and a temperature T of the secondary battery 6.
Is connected. The calculation unit 1a of the controller 1 calculates the SOC of the secondary battery 6 based on the detection values of the sensors described above, and the control unit 1b calculates the SOC of the engine 2, the inverter 5, and the like based on the detection values and the SOC.
The motor 3 is controlled.

Next, a method of calculating the amount of charge performed by the calculation unit 1a of the controller 1 will be described. FIG. 2 shows the state of charge SOC obtained by calculation (hereinafter referred to as state of charge RSOC).
FIG. 5 is a conceptual diagram showing a comparison between a true charge SOC and a true charge SOC.
(A) shows a charge amount RSOC based on a current integrated value (hereinafter referred to as an Ah integrated value) obtained by integrating a current value I during charge and discharge, and (b) shows a charge by a charge amount calculation method of the present invention. Quantity RS
Indicates OC. Here, in both cases (a) and (b), the charge amount RSOC is calculated basically using the following equation (1).

RSOC (%) = [1-Ah / Ah (Pmin)] × 100 (1) In the basic formula (1), Ah is an integrated value of Ah, and Ah (Pmi
n) is the battery capacity of the secondary battery. The method for calculating the battery capacity Ah (Pmin) will be described later. Note that Ah (Pmin) may simply be a rated capacity (three-hour rate capacity or the like).

In the state of charge RSOC shown in FIG. 2A, only the Ah integrated value obtained by integrating the current value I during charging and discharging is used as Ah. In this case, for example, if the current value I has an error ΔI as described above, the error ΔI of the current value I is accumulated in the Ah integrated value, and the charge amount at the start of the SOC calculation as shown in FIG. Even if RSOC is equal to the true state of charge SOC, the error with respect to the true state of charge SOC increases as the calculation is performed.

Incidentally, a lithium ion battery or the like is used as a secondary battery. In a lithium ion battery, there is a certain correlation between the open-circuit voltage and the state of charge SOC regardless of the degree of deterioration or temperature of the battery. Also, its reproducibility is very good. FIG. 3 is a diagram showing an example of such a correlation. When the open circuit voltage is known, the SOC is uniquely determined from this correlation. In FIG. 3, the open-circuit voltage corresponding to the state of charge SOC = 100% is OCV (100).
If OCV (100) is obtained, the charge amount SO of the secondary battery at that time SO
It can be determined from the correlation diagram that C is 100%.

Therefore, in the charge amount calculation method according to the present invention, the open circuit voltage is measured or estimated, and the charge amount SOC is calculated from the obtained open circuit voltage and the correlation shown in FIG. The difference (corresponding to an error) between the charge amount SOC (hereinafter referred to as charge amount CAPSOC) and the charge amount RSOC calculated by the basic formula (1) based on the integrated value of Ah is equal to or greater than a predetermined value. If
The Ah integrated value is replaced with the Ah integrated value (hereinafter, referred to as the current integrated value CAPAH) corresponding to the current charge amount CAPSOC, and reset. The current integrated value CAPAH is calculated by the following equation (2).

## EQU2 ## CAPAH = Ah (Pmin) × (1-CAPSOC / 100) (2)

Since the error is not accumulated in the charge amount CAPSOC unlike the charge amount RSOC calculated using the integrated value of Ah, FIG.
(B) As shown by the dashed line, a value close to the true state of charge SOC is obtained. In the example shown in FIG. 2B, the charge amount RSOC whose error gradually increases from the start of the calculation is reset by the value of the charge amount CAPSOC at time t1. And time t
In the state of charge RSOC replaced by RSOC = CAPSOC in 1, the error with the true state of charge SOC increases as the error of the integrated Ah value of the basic equation (1) increases, and the error becomes equal to or greater than a predetermined value. At that point, the reset is performed again. in this way,
In the S charge amount calculation method according to the present invention, if the error from the true charge amount SOC is equal to or more than a predetermined value, the above-described reset is performed. Therefore, the error between the calculated value RSOC and the true charge amount SOC is equal to or less than the predetermined value. It becomes possible to suppress to.

The following three types of open-circuit voltages can be considered when calculating the charge amount CAPSOC using the correlation shown in FIG. The open-circuit voltage E1 measured and measured when there is no load. The open-circuit voltage E2 estimated by the IV characteristic obtained from the current value and the voltage value sampled during charging and discharging, that is, the power calculation (discharge IV extrapolation). The open circuit voltage E3 estimated by the following equation (3) based on the value and the total voltage value

E3 = (total voltage) + (current) × (internal resistance corrected for temperature / deterioration) (3)

[Calculation of SOC by open circuit voltage E1]
FIG. 4 shows the state of charge R based on the measured open circuit voltage E1 described above.
It is a figure explaining the method of resetting SOC, (a)
Is a correlation diagram between the open circuit voltage E1 and the state of charge SOC, and (b) is a state of charge RO
It is a figure which shows the time change of SC. In the example shown in FIG. 4B, the reset is performed at times t2 and t3 after the start of the calculation. The open circuit voltage E1 at time t2 is changed to E1 (2)
Then, the charge amount CAPSOC2 is obtained from the correlation in FIG. Then, the charge amount RSOC at time t2 is changed to the charge amount CA.
Reset to PSOC2. That is, Ah at time t2
The integrated value is reset to the integrated current value CAPAH obtained by substituting the charge amount CAPSOC2 into the equation (2). Similarly, at time t3, the charge amount CAPSOC3 is obtained from the open circuit voltage E1 (3), and the charge amount RSOC at time t3 is reset to the charge amount CAPSOC3. The two-dot chain line RSOC ′ in FIG.
2 shows the SOC calculation value when the reset is not performed at t3. Since the open circuit voltage E1 can be measured only when there is no load, for example, the open circuit voltage E1 is measured when there is no load at the time of starting the vehicle (before the strong power is turned on) or when the key is turned off.

[Calculation of SOC by Open Voltage E2]
First, the estimated open circuit voltage E2 obtained by the power calculation described above is used.
The calculation method of will be described with reference to FIG. At first,
A current value I and a voltage value V are sampled by detecting a change in the current of the secondary battery. The crosses in FIG. 5 indicate the sampling data on the IV coordinate, and the characteristic curve L is obtained by performing a linear regression operation on the IV characteristic based on the sampling data. The value at the intersection of the straight line L and the vertical axis (voltage) is the estimated open circuit voltage E2. From the intersection of the straight line L and the discharge lower limit voltage (lower limit voltage for use as a vehicle system) Vmin,
The maximum output Pmax = Vmin × Imax of the secondary battery at that time is calculated as the power calculation value P. Further, the internal resistance R of the secondary battery can be calculated from the slope of the straight line L. Here, Imax indicates that the voltage on the straight line L is lower than the discharge lower limit voltage Vmin.
The discharge lower limit voltage Vmin is determined from the following factors (a) and (b). (A) Lower limit voltage of operating voltage range considering battery life (discharge end voltage) (b) Lower limit voltage of operating voltage range capable of guaranteeing performance and function of vehicle mounted unit

FIGS. 6A and 6B are diagrams for explaining the reset of the charged amount RSOC. FIG. 6A is a correlation diagram similar to FIG. 4, and FIG. 6B is a diagram showing a time change of the charged amount RSOC. If the estimated open circuit voltage E2 is obtained by the power calculation described above, FIG.
The charge amount CAPSOC4 is obtained from the correlation diagram of (a), and the charge amount RSOC at that time is reset to the charge amount CAPSOC4. Since the open-circuit voltage can be estimated only intermittently by the power calculation, the change in the charge amount CAPSOC becomes a line graph as shown in FIG. 6B. The calculated charge amount CAPSOC fluctuates above and below the true charge amount SOC, but this variation is due to a discharge IV sampling error.

[Calculation of SOC by Open Voltage E3]
7A and 7B are diagrams for explaining the SOC calculation based on the open-circuit voltage E3. FIG. 7A is a correlation diagram, and FIG.
FIG. 4 is a diagram showing a change over time of a charged amount RSOC. When the current value of the secondary battery at the time of charging and discharging is represented by I, the voltage value is represented by V, and the corrected internal resistance is represented by R, the above equation (3) is represented by the following equation (4).

E3 = V + I × R (4) where R is an internal resistance initial value R0, a temperature correction coefficient α,
It is expressed as Expression (5) using the internal resistance deterioration correction coefficient γ. The temperature correction coefficient α and the internal resistance deterioration correction coefficient γ
Will be described later.

R = R0 / (α × γ) (5)

The charge amount CAPSOC5 is obtained from the open circuit voltage E3 estimated from the equation (4) and the correlation diagram of FIG.
As shown in (b), the charge amount RSOC is reset to the charge amount CAPSOC5. The open circuit voltage E3 calculated by the equation (4) can be sequentially obtained from the measured I and V. However, when the current value I is large, the error due to the correction coefficient γ increases, and when the battery capacity is small, the diffusion voltage increases. Since the resistance is increased and the SOC is decreased, it is effective to calculate the open circuit voltage E3 when the current value I is small. For example, it is used when the current value I satisfies I ≦ 5CA. C is the rated capacity, and the rated capacity is 3
In the case of Ah, 5C becomes 15A. Hereinafter, the description will be made assuming that the upper limit value of the current value I at the time of calculation is 5 CA (= 15 A).

As described above, when the charge amount RSOC is reset using the charge amount CAPSOC obtained from the open-circuit voltages (E1 to E3), the charge amount CAPSOC obtained by any one of the above-described methods 1 to 3 is used. Reset may be performed, or these may be used in combination. However, in the case of (1), the open-circuit voltage at no load can be obtained only at the time of starting and stopping. Therefore, it is preferable that the resetting is performed in combination with another one, rather than resetting only with the obtained charge amount CAPSOC.

In the following, a description will be given of a case where resetting is performed by combining the above three. (A) At startup,
The difference between the charge amount CAPSOC based on the open circuit voltage E1 and the charge amount RSOC based on the integrated value of Ah is a predetermined value Δ1 (for example, Δ1 = 1
%) Or more, and (b) at the time of traveling, reset when the deviation between the charge amount CAPSOC based on the open circuit voltage E2 and the charge amount RSOC based on the integrated value of Ah is equal to or greater than a predetermined value Δ1. .

When the load fluctuation is small, such as when the vehicle is traveling at a constant speed, the regression line L in FIG. 5 cannot be obtained, so that the open circuit voltage E2 cannot be estimated. If the open-circuit voltage E2 is not obtained, the above-mentioned deviation cannot be obtained, and it cannot be evaluated whether or not to perform the reset.
Even if the OC deviation is actually equal to or larger than the predetermined value Δ1, there is a disadvantage that the reset is not performed. Therefore,
In order to prevent such inconvenience, when it is determined that power calculation is not possible, such as when driving at a constant speed, the open voltage E3
If the deviation between the charge amount CAPSOC based on the calculated value and the RSOC based on the integrated value of Ah is equal to or greater than a predetermined value Δ2, the charge amount RSOC is reset with the calculated charge amount CAPSOC. Here, the predetermined value Δ2
Is set to a value that satisfies Δ2 ≧ Δ1 (for example, 5%).

During running, the open circuit voltage E2 and the open circuit voltage E3
When the reset is performed with the charge amount CAPSOC based on the following equation, the charge amount RSOC may suddenly change when the Ah calculation value is replaced with the current integrated value CAPAH calculated by the equation (2). Therefore, in order to prevent the control of the system from becoming unstable due to such a sudden change in the state of charge SOC during traveling, for example, gradually over several tens of seconds (10 seconds in the case of the following equation (6)). To charge
Change the RSOC to the value of the charge amount CAPSOC. That is, the charge amount RSO is calculated using the current integrated value CAPAH calculated by the following equation (6).
Calculate C.

CAPAH = [{Ah (Pmin) × (1-CAPSOC / 100)} × T / 10 + {CAPAH × (1-T / 10)} (6)

FIG. 8 is a functional block diagram of the arithmetic unit 1a of the controller 1 shown in FIG. Reference numeral 22 denotes an Ah operation unit that integrates the current value I from the current sensor 9 to calculate an Ah integrated value, and 23 is charged from the Ah integrated value and the battery capacity Ah (Pmin) calculated by the battery capacity arithmetic unit 20. RSOC to calculate quantity RSOC
It is an operation unit. Reference numeral 21 denotes a voltage value V from the voltage sensor 8 and a current value I from the current sensor 9 to sample an open voltage E2 and an internal resistance R of the secondary battery 6 (see FIG. 1).
And an instantaneous power calculation unit 25 for calculating a power calculation value P. Reference numeral 25 denotes a formula (4) based on the voltage value V and the current value I.
Is an open-circuit voltage E3 calculation unit that calculates the open-circuit voltage E3 from The power calculation unit 21 also determines whether power calculation is possible based on the sampled voltage value V and current value I.

The calculated open-circuit voltages E2 and E3 and the open-circuit voltage E1 detected when there is no load are input to the CAPAH calculator 24. The CAPAH calculator 24 calculates (a) the open-circuit voltages E1 to E3
Of the charge amount CAPSOC according to (b) The calculated charge amount
Calculation of the deviation between CAPSOC and the charge amount RSOC calculated by the RSOC calculation unit 23, (c) Current integrated value CA corresponding to charge amount CAPSOC
The calculation of PAH is performed, and the integrated current CAPAH of (c) is output to the RSOC calculation unit 23 according to the magnitude of the deviation.

That is, the CAPAH calculation unit 24 determines that the deviation from the charge amount CAPSOC based on the open-circuit voltages E1 and E2 is a predetermined value Δ
When the value is 1 or more, the current integrated value CAPAH calculated from the charge amount CAPSOC based on the open voltage E1 is output if the vehicle is running, and the charge amount CAPSO based on the open voltage E2 is calculated if the vehicle is running.
Outputs the current integrated value CAPAH calculated from C. On the other hand, if the deviation from the charge amount CAPSOC based on the open voltage E3 becomes equal to or more than the predetermined value Δ2 during traveling, the integrated current CAPAH calculated from the charge amount CAPSOC based on the open voltage E3 is output.

In the CAPAH calculating section 24, for example, a table of SOC vs. open voltage as shown in FIG. 3 is stored in a memory (not shown) of the controller 1 in advance, and the charge amount CAPSOC is used by using the table. Ask for it. RSOC
The calculation unit 23 calculates the current integrated value CAPAH from the CAPAH calculation unit 24.
Is received, the Ah operation value used for calculating the charge amount RSOC is replaced with the received current integrated value CAPAH.

[Description of Battery Capacity Computing Unit 20] Next, an outline of a method of calculating the battery capacity Ah (Pmin) in the battery capacity computing unit 20 will be described. FIG. 9 is a diagram for explaining the temperature correction and the deterioration correction of the initial characteristics of the secondary battery 6, and each shows the relationship Ah (P) between the power characteristics and the amount of discharged electricity. FIG.
The curve L1 in (a) shows the initial characteristics of the battery (when there is no deterioration and the battery temperature is the reference temperature). In the case of a lithium ion battery or the like, Ah (P) is an n-th order expression of power P. Can be approximated by The initial characteristic L1 can be approximated by the following equation (7).

Ah (P) = aP ³ + bP ² + cP + d (7) Here, the coefficients a, b, c, and d are determined from the characteristics of the initial battery.

For the initial characteristic L1, a temperature correction coefficient α
Is performed, the temperature correction characteristic L shown in FIG.
2 is obtained. This temperature correction characteristic L2 is expressed by the following equation (8).

Ah (P) = Ah (P / α) = a (P / α) ³ + b (P / α) ² + c (P / α) + d (8) As can be seen from FIG. 9B. Is a proportional component to the power, and the P intercept Pref of the temperature correction characteristic L2 is Pref = P0
× α. The temperature correction coefficient α is a parameter representing a change in the internal resistance of the secondary battery, and is based on the battery temperature T from the temperature sensor 10.
1 is a table reference value corresponding to the temperature T.
P0 is a P intercept of the characteristic L1.

Further, the temperature-corrected equation (8) is subjected to deterioration correction as represented by the following equation (9), whereby the temperature-corrected and deterioration-corrected relational expression Ah (P)
Is calculated by the power capacity calculation unit 203.

Ah (P) = β × Ah (P / αγ) = aβ (P / αγ) ³ + bβ (P / αγ) ² + cβ (P / αγ) + dβ (9) where γ is the battery Β is a parameter representing a change in internal resistance, and β is a parameter representing a change in electric capacity, and is called an internal resistance deterioration correction coefficient and a capacity deterioration correction coefficient, respectively. Battery capacity A described above
h (Pmin) is obtained by substituting the minimum guaranteed output Pmin required for the vehicle system into Ah (P) obtained by equation (9).

The above-mentioned internal resistance deterioration correction coefficient γ is calculated based on the temperature correction coefficient α calculated by the α calculation section 201 and the internal resistance R calculated by the instantaneous power calculation section 21 in the γ calculation section of the battery capacity calculation section 20. In step 202, it is calculated by the following equation (10).

Γ = (R0 / α) / R (10) where R0 is the initial internal resistance of the battery. On the other hand, the capacity deterioration correction coefficient β is calculated based on the Ah integrated value calculated by the Ah calculating section 22 and the Ah (P / α) calculated by the power capacity calculating section 203.
Based on γ), β calculation section 204 of battery capacity calculation section 20 calculates the following equation (11).

Β = (Ah integrated value) / Ah (P / αγ) (11) Ah (P) represented by the equation (9) is as shown by a curve L3 in FIG. 9C. In FIG. 9C, a curve L2 'is a characteristic curve L2.
Is a curve corrected by the internal resistance deterioration correction coefficient γ, and the characteristic curve L2 is obtained by correcting the curve L2 ′ by the capacity deterioration correction coefficient β.

The above-described method is applicable as long as there is a correlation that can be expressed by the above-described parameters in the relationship between the power characteristics and the amount of discharged electricity, regardless of the type of battery such as a lead-acid battery or a nickel-metal hydride battery. Can be used. However, temperature compensation,
It is necessary to examine which coefficient (α, β, γ) the deterioration correction is applied to for each battery. Note that Ah (P) does not necessarily need to be approximated by an n-th order expression of P. For example, if a relationship between P and Ah is provided as a table, a solution can be obtained in the same manner as the calculation procedure described above by using interpolation calculation. Can be.

FIG. 10 is a flowchart showing the procedure for calculating the charge amount. The flow starts when the IG key is turned on. In the following, the charge amount based on the open-circuit voltages E1 and E2
CAPSOC is referred to as charge amount ECAPSOC, and the charge amount CAPSOC based on the open circuit voltage E3 is referred to as charge amount VCAPSOC. Step S1 is a step of determining whether or not there is no load,
In the case of a no-load state, the process proceeds to step S2, and in the case of a load state (during charging and discharging), the process proceeds to step S7. If the process proceeds from step S1 to step S2, step S2
To calculate the open circuit voltage E1 and obtain the charge amount ECAPSOC based on the open circuit voltage E1 from the correlation shown in FIG. 3, and then proceed to step S3.

On the other hand, when the process proceeds from step S1 to step S7, it is determined in step S7 whether or not the power calculation is possible (for example, the change in the current value I and the voltage value V is detected in the instantaneous power calculation unit 21). Judgment is made based on whether or not a predetermined number or more of sampling data has been collected).
If the power calculation is possible, the process proceeds to step S8. If the power calculation is not possible, the process proceeds to step S10. Step S8
Then, the open circuit voltage E2 is calculated and the open circuit voltage E2
Is obtained from the correlation shown in FIG. 3, and then the process proceeds to step S3. Note that the charge amount is determined in step S8.
In calculating ECAPSOC, a moving average of the open circuit voltage E2, that is, an average value of the past three values obtained by calculation is used. Next, in step S3, the charge amount RSO with respect to the charge amount ECAPSOC calculated in step S2 or step S8.
The deviation ESOCOFS of C (obtained from the integrated value of Ah) is calculated by the following equation (1)
It is calculated by 2).

[Equation 12] ESOCOFS = RSOC−ECAPSOC (12)

In step S4, the absolute value of the deviation ESOCOFS is 1
This step is a step of determining whether or not the charge amount is equal to or more than 1%. If it is not less than 1%, the process proceeds to step S5. If it is less than 1%, the process proceeds to step S9. After that, the process proceeds to step S16. In step S5, the charge amount CA of equation (2) (or equation (6))
The current integrated value CAPAH is calculated by substituting the charge amount ECAPSOC calculated in step S2 or step S8 into PSOC, and the Ah integrated value is reset with the current integrated value CAPAH. Step S
In step 6, the amount of charge RSOC based on the current integrated value CAPAH calculated in step S5 is calculated by equation (1), and then the process proceeds to step S16.

When it is determined in step S7 that the power calculation is impossible and the process proceeds to step S10, it is determined in step S10 whether the current value I is 15 A or less. S1
The process proceeds to step S1, and if it exceeds 15A, the process proceeds to step S9. In step S11, the open circuit voltage E3 under load is calculated by equation (4), and the charge amount V based on the open circuit voltage E3 is calculated.
CAPSOC is determined from the relationship shown in FIG. In step S12, the deviation VSOCOFS of the charge amount RSOC (obtained from the integrated value of Ah) with respect to the charge amount VCAPSOC calculated in step S11.
Is calculated by the following equation (13).

[Expression 13] VSOCOFS = RSOC−VCAPSOC (13)

Step S13 is a step for determining whether or not the absolute value of the deviation VSOCOFS is 5% or more. If the absolute value is 5% or more, the process proceeds to step S14, where the charge amount CAPSOC of the equation (2) or (6) is calculated. The charge amount VCAPSO in step S11
The Ah integrated value is reset by the current integrated value CAPAH obtained by substituting C, and if it is smaller than 5%, the process proceeds to step S9.
Next, in step S15, if the amount of charge RSOC based on the integrated current value CAPAH calculated in step S14 is calculated by equation (1), the process proceeds to step S16.

Steps S16 to S20 are steps relating to learning of the internal resistance deterioration correction coefficient γ and the capacity deterioration correction coefficient β, and are updated to the latest γ and β by executing these steps. First, step S1
Step 6 is a step for determining whether or not the power calculation condition is satisfied, that is, whether or not a predetermined number or more of sampling data that captures changes in the current value I and the voltage value V has been collected. Proceed to step S17. In step S17, the state of charge RSOC is set to a predetermined value KCMSOC (for example, 40
%) Is a step of determining whether or not the charge amount RSOC
If the value is smaller than the predetermined value KCMSOC, the process proceeds to step S19. If the value is equal to or larger than the predetermined value KCMSOC, the process proceeds to step S18 to update γ with γ calculated by the following equation (14), and then proceeds to step S19.

Γ = (R0 / α) / R (14) where R0 is an internal resistance initial value and R is an internal resistance calculated by power calculation.

In step S19, the charge amount RSOC is set to the predetermined value KCLS.
This is a step of determining whether or not the charge amount is equal to or less than OC (for example, 50%). When the charge amount RSOC is larger than the predetermined value KCLSOC, the process returns to step S7. Β calculated by the following equation (15)
After returning to step S7, the process returns to step S7.

Β = CAPAH / Ah (P / αγ) (15) However, the latest value is used for the current integrated value CAPAH.

As described above, in the present embodiment,
If the error of the charge amount RSOC based on the integrated value of Ah becomes equal to or more than the predetermined value Δ1 or Δ2, the integrated value of Ah when calculating the charge amount RSOC is replaced with the integrated current value CAPAH calculated from the open-circuit voltages E1 to E3. This can reduce the influence of the accumulated error of the integrated Ah value on the charged amount RSOC. Further, by appropriately using the open-circuit voltages E1 to E3 in accordance with the traveling state, for example, when the vehicle is traveling at a constant speed or when the current value I exceeds 15A, the charge amount can be accurately calculated in various traveling patterns. .

In the above-described embodiment, Ah
The charge amount RSOC is calculated based on the integrated value, and if the error increases, the Ah integrated value of the charge amount RSOC is changed to the open circuit voltage E1 to
The correction is made by replacing the current integrated value CAPAH calculated from E3, but the method of calculating the charge amount RSOC using the integrated Ah value, the charge amount RSOC using the integrated current value CAPAH calculated from the open circuit voltage E1 A method for calculating the amount of charge RSOC using the integrated current value CAPAH calculated from the open-circuit voltage E2, and a method for calculating the amount of charge RSOC using the integrated current value CAPAH calculated from the open-circuit voltage E3. The charge amount RSOC may be calculated using at least two of the methods. Also in this case, the charge amount calculation accuracy is improved as compared with the case where the charge amount RSOC is calculated based on the Ah integrated value, and the charge amount can be accurately calculated in various traveling patterns.

In the correspondence between the embodiment described above and the elements of the claims, the open-circuit voltages E2 and E3 constitute the open-circuit voltage calculation value, and the open-circuit voltage E2 represents the first open-circuit voltage and the open-circuit voltage E3 Constitutes a second open circuit voltage. Further, the current sensor 9 is a current detecting unit, the voltage sensor 8 is a voltage detecting unit, the Ah calculating unit 22 is a current integrating unit,
The instantaneous power calculator 21 and the open-circuit voltage E3 calculator 25 constitute open-circuit voltage calculator, the RSOC calculator 23 constitutes first charge amount calculator, and the CAPAH calculator 24 constitutes second charge calculator. RSOC operation unit 23 and CAPAH operation unit 2
4 constitutes a correction means.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a parallel hybrid vehicle.

FIG. 2 is a conceptual diagram of a change in a state of charge SOC, in which (a) shows a state of charge RSOC and a true state of charge SOC based on an integrated value of Ah;
(B) is a charged amount RSOC by the charged amount calculating method according to the present invention.
FIG.

FIG. 3 is a diagram showing a correlation between an open circuit voltage and a state of charge SOC.

4A and 4B are diagrams for explaining reset of a charge amount RSOC based on an open voltage at the time of no load, and FIG. 4A illustrates an open voltage and a charge amount SO;
FIG. 4B is a diagram illustrating a correlation with C, and FIG.

FIG. 5 is a diagram illustrating power calculation.

6A and 6B are diagrams for explaining reset of a charged amount RSOC based on an open circuit voltage E2, wherein FIG. 6A is a diagram illustrating a correlation between an open circuit voltage and a charged system SOC, and FIG. 6B is a diagram illustrating a change in the charged system RSOC.

FIGS. 7A and 7B are diagrams for explaining reset of a charged amount RSOC based on an open-circuit voltage E3, where FIG. 7A is a correlation diagram between the open-circuit voltage and a charged amount SOC, and FIG. 7B is a diagram illustrating a change in the charged amount RSOC.

FIG. 8 is a functional block diagram of a calculation unit 1a.

9A and 9B are diagrams illustrating temperature correction and deterioration correction of initial characteristics of the secondary battery, and FIG. 9A is a diagram illustrating initial characteristics L1;
(B) is a diagram illustrating a temperature correction characteristic L2, and (c) is a diagram illustrating a temperature-corrected and deterioration-corrected characteristic L3.

FIG. 10 is a flowchart showing a calculation procedure of a state of charge SOC.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Controller 1a Operation part 1b Control part 2 Engine 3 Motor 6 Secondary battery 8 Voltage sensor 9 Current sensor 10 Temperature sensor 20 Battery capacity operation part 21 Instantaneous power operation part 22 Ah operation part 23 RSOC operation part 24 CAPAH operation part 25 Open voltage E3 operation unit 201 α operation unit 202 γ operation unit 203 power capacity operation unit 204 β operation unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H02J 7/00 B60K 9/00 Z F-term (Reference) 2G016 CA03 CB06 CB11 CB12 CB13 CB21 CB31 CB32 CC01 CC04 CC07 CC12 CC14 CC24 CC27 5G003 AA07 BA01 CA05 CA16 CA20 DA04 EA05 FA06 GB06 5H030 AA08 AS08 FF42 FF43 FF44 5H115 PG04 PI16 PO17 PU01 PU23 PU25 QE10 QI04 TI01 TI05 TI06 TI10 TI10

Claims (9)

[Claims] 1. A first calculation method of: (a) integrating a current value of a secondary battery during charging and discharging, and calculating a charge amount of the secondary battery based on the integrated current value; (b) no load A second calculation method for calculating the charge amount of the secondary battery based on the terminal voltage of the secondary battery in the state, (c) by power calculation based on the terminal voltage value and the current value of the secondary battery during charging and discharging A third calculation method of calculating a first open-circuit voltage of the secondary battery and calculating a charge amount of the secondary battery based on the first open-circuit voltage; In a fourth calculation method, a second open-circuit voltage is calculated based on a terminal voltage value, the current value, and the internal resistance value, and a charge amount of the secondary battery is calculated based on the second open-circuit voltage. Calculating the amount of charge of the secondary battery by at least two of the calculation methods described above. A method for calculating the charge amount of a lid car. 2. The charge amount calculation method according to claim 1, wherein the charge amount of the secondary battery is calculated using the first calculation method and the third calculation method. Charge amount calculation method. 3. The charge amount calculation method according to claim 1, wherein the charge amount of the secondary battery is calculated using the first calculation method and the fourth calculation method. Charge amount calculation method. 4. The charge amount calculation method according to claim 1, wherein the charge amount of the secondary battery is calculated using the first calculation method, the second calculation method, and the third calculation method. A method for calculating the charge amount of a hybrid vehicle, characterized in that: 5. The method of calculating a charge amount according to claim 1, wherein the charge amount of the secondary battery is calculated using the first calculation method, the second calculation method, and the fourth calculation method. A method for calculating the charge amount of a hybrid vehicle, characterized in that: 6. A charge amount calculation method for a hybrid vehicle, comprising: calculating an integrated current value based on a charge / discharge current value of a secondary battery; and calculating a first charged amount of the secondary battery based on the integrated current value. In (a), a second charge amount is calculated based on a terminal voltage value of the secondary battery in a no-load state, and a difference between the second charge amount and the first charge amount is equal to or more than a predetermined value. When the first
(B) calculating a first open-circuit voltage by a power calculation based on a terminal voltage value and a current value at the time of charging and discharging of the secondary battery. When the difference between the third charge amount calculated based on the first open circuit voltage and the first charge amount is equal to or greater than a predetermined value, the first charge amount is changed to the third charge amount. (C) calculating a second open-circuit voltage based on a terminal voltage value, a current value, and an internal resistance value during charging and discharging of the secondary battery, and based on the second open-circuit voltage. A third correction method for replacing the first charge amount with the fourth charge amount when a difference between the fourth charge amount calculated by the calculation and the first charge amount becomes equal to or greater than a predetermined value. Wherein the first charge amount is corrected by using at least two correction methods. Car of the charge amount calculation method. 7. The hybrid vehicle according to claim 6, wherein the first charge amount is corrected using the first correction method and the second correction method. Charge amount calculation method. 8. The hybrid vehicle according to claim 6, wherein the first charge amount is corrected using the first correction method and the third correction method. Charge amount calculation method. 9. A current detecting means for detecting a charge / discharge current value of a secondary battery, a current integrating means for calculating a current integrated value based on a current detected value of the current detecting means, and A charge amount calculating device for a hybrid vehicle, comprising: first charge amount calculating means for calculating a first charge amount of the secondary battery; voltage detecting means for detecting a terminal voltage of the secondary battery; Means for calculating an open-circuit voltage of the secondary battery based on a detection value of the means and a detection value of the voltage detection means, and a second charge amount according to the open-circuit voltage calculation value by the open-circuit voltage calculation means. A second charge amount calculating means for calculating, when the difference between the first charge amount and the second charge amount is equal to or greater than a predetermined value, the first charge amount is calculated based on the second charge amount. Correction means for correcting the charge amount. A charge amount calculation device for a hybrid vehicle, characterized in that: