JP2013083496A - State-of-charge estimation device and method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a state-of-charge estimation device capable of reducing an estimated error in state-of-charge of a battery.SOLUTION: A battery state-of-charge estimation device comprises: current integration method-based state-of-charge calculation means 3 for calculating a current integration method-based state-of-charge by integrating charge and discharge currents; open voltage estimation method-based state-of-charge calculation means 4 for calculating an open voltage estimation method-based state-of-charge from an open voltage of a battery estimated from the charge and discharge currents and a terminal voltage; variation limit value calculation means 5 for calculating an upper limit value and a lower limit value from current integration method-based state-of-charge variation calculated from the current integration method-based state-of-charge; and variation limit processing means 6 for calculating a state-of-charge of a battery, by limiting open voltage estimation method-based state-of-charge variation so that a state-of-charge variation calculated using the open voltage estimation method-based state-of-charge is within the range between the upper limit value and the lower limit value and by changing an open voltage estimation method-based state-of-charge.

Description

  The present invention relates to a battery charge rate estimation apparatus and method for estimating a battery charge rate used in an electric vehicle or the like.

  For example, in an electric vehicle or a hybrid electric vehicle, charging is performed from an electric motor that supplies electric power to an electric motor that drives these vehicles, an electric motor that functions as a generator during braking, or a power supply installed on the ground. In order to store electrical energy, a rechargeable battery (secondary battery) is used.

In this case, in order to keep the battery in an optimal state over a long period of time, it is necessary to constantly monitor the state of the battery, particularly the state of charge (SOC), and perform battery management.
As a conventional charge rate detection method, the battery voltage and current are all recorded in time-series data, and the current is time-integrated using these data to determine the current charge amount and the battery is charged. Current integration method (also called Coulomb count method or sequential state recording method) to obtain the charging rate using the initial charge value and full charge capacity, and the battery input current value and terminal voltage value are input, and the battery equivalent circuit An open-circuit voltage estimation method is known in which an open-circuit voltage value, which is a model state quantity, is sequentially estimated using a model, and a charging rate is estimated from the open-circuit voltage value.

Each of the above methods has advantages and disadvantages, and the former current integration method is higher in accuracy than the latter open-circuit voltage estimation method in which the charge rate is estimated using the open-circuit voltage value in estimating the charge rate in a short time. However, continuous observation is required, and as time goes on, errors accumulate and accuracy decreases. On the other hand, the latter open-circuit voltage estimation method does not require constant observation, but the open-circuit voltage variation with respect to the change in the charging rate is small. It is inferior to the law.
Therefore, the charging rate (SOC _C ) obtained by the current integration method and the charging rate (SOC _v ) obtained by the open circuit voltage estimation method so as to reduce the estimation error of the charging rate obtained by these methods, and An apparatus and a method for improving the estimation accuracy of the charging rate by using both the charging rates are known.

As one of such conventional battery charge rate estimation devices, a battery information acquisition unit that obtains current data, voltage data, and temperature data by measuring the current, voltage, and temperature of the battery, and integrates the current data. A current integrating unit that calculates a charging rate (SOC _C ), an electromotive force calculating unit that calculates an electromotive force (OCV) using an equivalent circuit model that simply represents current data, voltage data, and a battery through an electric circuit; A SOC _v estimator that estimates the charging rate (SOC _v ) using the calculated electromotive force (OCV) and temperature data, and determines a battery current state in a certain time interval, and uses at least one of SOC _C and SOC _v There is known a battery management system including an SOC setting unit that sets a battery charge rate (SOC) (see, for example, Patent Document 1).
Here, in the SOC setting unit, if the fixed time interval is 20 seconds to 60 seconds and the battery current state is a low current state in the time interval, the charge rate (SOC _v ) is changed to the battery charge rate (SOC). In other cases, the charging rate (SOC _C ) is set to the battery charging rate (SOC).

Special table 2011-515651 gazette

However, in the above-described conventional battery management system, in the electromotive force (OCV: open circuit voltage) estimation, even in the case of a low current state, it is caused by the state of the input signal (frequency component, noise, etc.) immediately after the estimation is started. There is a problem that the estimated charging rate may deviate from the true charging rate due to an abnormal transient response or an estimation result hunting.
Also, if the battery current state does not become a low current state for a long time, the charging rate (SOC _i ) by the current integration method continues for a long time, and as a result, the integration error is accumulated and the estimated and correct values are accumulated. There is also a problem that the error becomes larger.

  The present invention has been made paying attention to the above problems, and an object of the present invention is to provide a charging rate estimation apparatus and method capable of suppressing an estimation error of a battery charging rate (SOC) to a small extent. There is to do.

For this purpose, the battery charging rate estimation device according to the first aspect of the present invention comprises:
Charge / discharge current detecting means for detecting the charge / discharge current of the battery;
Terminal voltage detecting means for detecting the terminal voltage of the battery;
A current integration method charging rate calculation means for calculating a current integration method charging rate by integrating the charging / discharging current detected by the charging / discharging current detection means;
The open-circuit voltage estimation method charging rate for estimating the open-circuit voltage of the battery from the charging / discharging current detected by the charge-discharge current detection unit and the terminal voltage detected by the terminal voltage detection unit, and calculating the open-circuit voltage estimation method charging rate from this open-circuit voltage A calculation means;
Change amount limit value calculation that calculates the current integration method charge rate change amount from the current integration method charge rate obtained by the current integration method charge rate calculation means, and calculates the upper limit value and the lower limit limit value from this current integration method charge rate change amount Means,
The open-circuit voltage estimation method The charge rate change amount is calculated using the open-circuit voltage estimation method charge rate obtained by the charging rate calculation means, and the charge rate so that the charge rate change amount falls within the range between the upper limit value and the lower limit value. An amount-of-change restriction processing means for calculating the charging rate of the battery by changing the open-circuit voltage estimation method charging rate by limiting the amount of change;
It is provided with.

Moreover, the battery charging rate estimation device according to claim 2 is:
The change amount limit value calculating means sets the upper limit limit value and the lower limit limit value by adding and subtracting a predetermined value to the current integration method charging rate change amount, respectively.
It is characterized by

The battery charge rate estimation device according to claim 3 is:
The change amount limit value calculating means sets an upper limit limit value and a lower limit limit value by multiplying the current integration method charging rate change amount by a predetermined value and a reciprocal of the predetermined value, respectively.
It is characterized by that.

The battery charge rate estimation apparatus according to claim 4 is:
Estimate the error between these from the current integration method charging rate and the open circuit voltage estimation method charging rate, and subtract the error from one of the current integration method charging rate and the open circuit voltage estimation method charging rate to limit the amount of change as the corrected charging rate. Error correction means for inputting to the means,
The change amount restriction processing means calculates the charge rate of the battery using the correction charge rate as the open-circuit voltage estimation method charge rate used in the change amount restriction processing means.
It is characterized by that.

Further, the battery charging rate estimation method according to the second invention of claim 5 is:
Accumulate the charge / discharge current of the battery detected by the charge / discharge current detection means to calculate the current integration method charging rate,
Estimate the open-circuit voltage of the battery from the charge / discharge current and the terminal voltage detected by the terminal voltage detection means, calculate the open-circuit voltage estimation method charging rate from this open-circuit voltage,
Obtain the current integration method charge rate change amount from the current integration method charge rate, calculate the upper limit value and the lower limit value from this current integration method charge rate change amount,
Open-circuit voltage estimation method Charge rate is calculated using the charge rate, and the open-circuit voltage estimation method is charged by limiting the charge rate change amount so that the charge rate change amount falls within the range between the upper limit value and the lower limit value. Calculate the battery charge rate by changing the rate,
It is characterized by that.

  In the battery charging rate estimation device according to the first aspect of the present invention, even in the case of a low current state, the estimated charging is performed immediately after the estimation is started or depending on the state of the input signal (frequency component, noise, etc.). Suppresses a large deviation from the true charge rate due to an abnormal transient response of the rate or hunting of the estimation result. Thereby, the estimation error of the charging rate of the battery can be reduced.

  In the battery charge rate estimation device according to claim 2, the change amount limit value calculation means uses the current integration method charge rate change amount obtained by the current integration method charge rate calculation means, and sets a predetermined value to this. Since the upper limit value is obtained by adding, and the lower limit value is obtained by subtracting the predetermined value A from the current integration method charging rate change amount, the upper limit value and the lower limit value can be easily obtained with a simple configuration. Can be obtained.

  In the battery charge rate estimation device according to claim 3, the change amount limit value calculation means uses the current integration method charge rate change amount obtained by the current integration method charge rate calculation means, and sets a predetermined value to this. Since the upper limit value is obtained by multiplying, and the lower limit value is obtained by multiplying the current integration method charging rate change amount by the reciprocal of the predetermined value, the upper limit value and the lower limit value can be easily obtained with a simple configuration. Can be obtained.

  In the battery charging rate estimation device according to claim 4, since the corrected charging rate corrected by the error correcting unit is used for the open-circuit voltage estimation method charging rate used by the variation amount limiting processing unit, the charging of the battery is performed. The rate can be estimated more accurately.

  In the battery charging rate estimation method according to the second aspect of the present invention, even in a low current state, the estimated charging is performed immediately after the estimation is started or depending on the state of the input signal (frequency component, noise, etc.). Suppresses a large deviation from the true charge rate due to an abnormal transient response of the rate or hunting of the estimation result. Thereby, the estimation error of the charging rate of the battery can be reduced.

It is a block diagram which shows the whole structure of the charging rate estimation apparatus which concerns on Example 1 of this invention. It is a figure which shows the battery model circuit used with the open | release estimation part of the charging rate estimation apparatus of Example 1 shown in FIG. In the charge rate estimation apparatus of Example 1, it is a figure which shows the simulation result of charge rate estimation. It is a block diagram which shows the whole structure of the charging rate estimation apparatus which concerns on Example 2 of this invention. It is a block diagram which shows the whole structure of the charging rate estimation apparatus which concerns on Example 3 of this invention. It is a block diagram which shows the whole structure of the charging rate estimation apparatus which concerns on Example 4 of this invention. It is a figure which shows the modification of the charging rate estimation apparatus which concerns on Example 3, 4 of this invention.

  Hereinafter, embodiments of the present invention will be described in detail based on examples shown in the drawings.

First, the overall configuration of the charging rate estimation apparatus according to Embodiment 1 of the present invention will be described.
The charging rate estimation apparatus according to the first embodiment estimates a charging rate (SOC: State of Charge) of a battery that supplies electric power to an electric motor or the like mounted on an electric vehicle.
As shown in FIG. 1, the charging rate estimation device connected to the battery BT includes a charging / discharging current detection unit 1, a terminal voltage detection unit 2, a current integration method charging rate estimation unit 3, and an open-circuit voltage estimation method charging rate. An estimation unit 4, a variation amount limit value calculation unit 5, and a variation amount limitation processing unit 6 are included.

  The battery BT is a rechargeable battery. In this embodiment, for example, a lithium ion battery is used. However, the battery BT is not limited to this, and other types of batteries such as a nickel hydrogen battery are used. Needless to say.

The charge / discharge current detection unit 1 collects a part of the braking energy by causing the electric motor to function as a generator during braking when the electric power is supplied from the battery BT to an electric motor (not shown) or the like. Alternatively, it detects the magnitude of the charging current when charging from a power supply facility on the ground. For example, the charging / discharging current value i flowing through the battery BT is detected using a shunt resistor or the like. The detected charge / discharge current value i is input to both the current integration method charging rate estimation unit 3 and the open-circuit voltage estimation method charging rate estimation unit 4.
Note that the current detection unit 1 is not limited to the above-described configuration, and those having various structures and formats can be appropriately employed, and correspond to the charge / discharge current detection means of the present invention.

The terminal voltage detector 2 detects the voltage between the terminals of the battery BT, and the detected terminal voltage value v is input to the open-circuit voltage estimation method charging rate estimator 4.
The terminal voltage detection unit 2 can appropriately adopt ones having various structures and formats, and corresponds to the terminal voltage detection means of the present invention.

  The current integration method charging rate estimation unit 3 includes an integrator 31, an open circuit voltage-charging rate calculation unit 32, a full charge capacity calculation unit 33, and a capacity ratio calculation unit 34. The current integration method charging rate calculation unit 3 corresponds to the current integration method charging rate calculation means of the present invention.

The integrator 31 receives the charge / discharge current value i detected by the charge / discharge current detection unit 1 and integrates the charge / discharge current value i over time to obtain an integrated current value (equal to the charged / discharged charge capacity). Is calculated to obtain the amount of charge charged / discharged in the battery BT. In this integration, the integrator 31 sets the full charge amount FCC of the battery BT to the value (initial charge rate SOC _O ) obtained by the later-described open circuit voltage value-charge rate relationship data calculation unit 32 as the initial capacity value. By multiplying, the initial charge capacity u ₀ is calculated. Next, the integrator 31 calculates the charge amount (remaining capacity) u ₁ stored in the battery BT by adding the current integrated value to the initial charging capacity u ₀ , and calculates the remaining capacity u ₁ . Output to the capacity ratio calculation unit 34.

The open-circuit voltage value-charge rate calculation unit 32 stores relation data between the open-circuit voltage value OCV and the charge rate SOC obtained in advance as a look-up table, and the terminal voltage detection unit 2 immediately before the start of charging / discharging. substantially equal open circuit voltage value OCV on the detected voltage value v is inputted, calculates the charge rate SOC corresponding to the open circuit voltage value OCV from the look-up table, the input to the integrator 31 as an initial charging rate SOC _O To do.

On the other hand, the full charge capacity calculation unit 33 stores a design capacity DC that is an initial value of the full charge capacity FCC, and a soundness level SOH (State of Health) of the battery BT is input and multiplied by the design capacity DC. The full charge capacity u ₂ of the battery BT at that time is obtained. The full charge capacity u ₂ is output to the capacity ratio calculator 34. Since the temporal change in the soundness level SOH is moderate, either the value stored when the vehicle power supply was turned off last time or the value calculated when the vehicle power supply was turned on this time may be used.

The capacity ratio calculator 34 divides the current integrated value (= remaining capacity) u ₁ input from the integrator 34 by the full charge capacity u ₂ input from the full charge capacity calculation unit 33, thereby charging the current integration method. The rate SOC _C is obtained, and this current integration method charge rate SOC _C is output to the variation limit value calculation unit 5.

  On the other hand, the open-circuit voltage estimation method charging rate estimation unit 4 includes a subtractor 41, an overvoltage calculation unit 42, an open-circuit estimation unit 43, and an open-circuit voltage value-charging rate calculation unit 44. The open-circuit voltage estimation method charging rate estimation unit 4 corresponds to the open-circuit voltage estimation method charging rate calculation means of the present invention.

The subtractor 41 receives the terminal voltage v detected by the terminal voltage unit 2 and the overvoltage v ₁ calculated by the overvoltage calculation unit 42, and the open circuit voltage OCV (OCV) obtained by subtracting the overvoltage v ₁ from the terminal voltage v. = V−v ₁ ) is output to the open circuit voltage value−charge rate calculation unit 44.

The overvoltage calculation unit 42 receives the charge / discharge current i detected by the charge / discharge detection unit 1 and the resistance value R estimated by the open-circuit estimation unit 43, which will be described later, and is multiplied by the charge / discharge current i and the resistance value R. v ₁ (= i × R) is obtained. This overvoltage v ₁ is output to the subtractor 41.

The open estimation unit 43 estimates the resistance R of the battery BT using an adaptive filter such as a Kalman filter based on the battery equivalent circuit model shown in FIG.
When the Kalman filter is used in the open-circuit voltage estimation method charging rate estimation unit 4, the same inputs (charge / discharge current i, battery temperature, etc.) as the actual battery BT are input to the battery equivalent circuit model of FIG. Output (terminal voltage v) is compared, and if there is a difference between them, the difference is multiplied by Kalman gain and fed back, and the battery equivalent circuit model is corrected so that the error is minimized. This is repeated sequentially to estimate an open circuit voltage value that is a true internal state quantity. The details are described in Japanese Patent Application No. 2011-007874 by the present applicant.

The battery equivalent circuit model uses a Foster-type RC ladder circuit (however, only a primary parallel circuit) as shown in FIG. That is, in this circuit, the resistance (R ₁ : Faraday impedance and the charge transfer process in the battery BT) in the bulk resistance (R ₀ ) that sets the direct current component such as the resistance of the electrolyte of the battery BT and the ohmic resistance due to the connection. A parallel circuit of a capacitor (set as a reaction resistance representing dynamic behavior) and a capacitor (C ₁ : set as a non-Faraday impedance and representing an electric double layer) is connected. Further, in the figure, OCV open circuit voltage value of the capacitor C _OCV representing the open circuit voltage, a terminal voltage value at v, also are respectively displayed overvoltage value generated in the parallel circuit at v _1. Terminal voltage v, as described above, is equal to the sum of the open circuit voltage value OCV and overvoltage value v _1. The resistance R is a value obtained by adding the bulk resistance R ₀ and the Faraday impedance R ₁ .

The open-circuit voltage value-charging rate calculation unit 44 is similar to the open-circuit voltage value-charging rate calculation unit 32 of the current integration method charging rate estimation unit 3, and the relational data between the open-circuit voltage value OCV and the charging rate SOC obtained in advance through experiments. Is stored as a look-up table, and the open-circuit voltage value OCV obtained by the subtractor 41 is input, and the open-circuit voltage estimation method charging rate SOC _V corresponding to the open-circuit voltage value OCV is obtained from the look-up table. Calculate and output to the variation restriction processing unit 6.

  The change amount limit value calculation unit 5 includes a differentiator 51, a predetermined value setting unit 52, an adder 53, and a subtractor 54.

The differentiator 51 receives the current integration method charging rate SOC _C obtained by the capacity ratio calculation unit 34, discretizes this by z conversion, and differentiates (differences) to obtain a current integration method charging rate differential value ΔSOC. _{Get C.} That is, this current integration method charging rate differential value ΔSOC _C represents the amount of change (rate) of the current integration method charging rate SOC _C , and this value is output to the adder 53 and the subtractor 54.

The predetermined value setting unit 52 sets a predetermined value A which is an optimum value determined in advance through experiments and simulations. The predetermined value A is a transient response value that causes the open-circuit voltage estimation method charge rate SOC _{V to} be an abnormal value by applying a predetermined limit to the magnitude of the charge rate change amount by the open-circuit voltage estimation method in the change amount restriction processing unit 6. Set to a value that can be limited within a range that does not cause hunting. The predetermined value A set here is input to the adder 53 and the subtractor 54.

The adder 53 adds the predetermined value A to the current integration method charging rate differential value [Delta] SOC _C obtained by the differentiator 51, and outputs the sum value to the variation restriction processing section 6 as the upper limit value vr _1.
Subtractor 54, the predetermined value A is subtracted from the current integration method charging rate differential value [Delta] SOC _C obtained by the differentiator 51, and outputs the subtracted value to the variation restriction processing section 6 as the lower limit value vr _2.

The upper limit value vr ₁ and the lower limit value vr ₂ are used to limit the amount of change ΔSOC _V of the open circuit voltage estimation method charging rate SOC _V. It should be noted that the amount of change in the open circuit voltage estimation method charging rate SOC _V is limited by the change amount limiting processing unit 6 using the amount of change in the current integration method charging rate (differential value ΔSOC _C ) in this way. This is because the current integration method is superior in principle to the open-circuit voltage estimation method in estimating the rate SOC fluctuation amount.

The change amount restriction processing unit 6 includes a differentiator 61 similar to the differentiator 51 of the change amount restriction value calculation unit 5 and a change amount restriction unit 62. The differentiator 61 calculates a change amount (differential value) ΔSOC _V of the input open-circuit voltage estimation method charging rate SOC _V and outputs it to the change amount limiting unit 62.

The change amount limiting unit 62, the change amount [Delta] SOC _V open circuit voltage estimation charging rate SOC _V from the differentiator 61 is also open voltage - open circuit voltage estimation charging rate SOC _V from the charging rate calculating unit 44 are inputted respectively, using the open-circuit voltage estimation SOC variation [Delta] SOC _V has limited the size of the upper limit value vr ₁ and the lower limit value release voltage estimation SOC change amount [Delta] SOC _V to be within the scope of the vr ₂ value , Opening voltage estimation method Charging rate SOC _V is changed.

That is, as shown in the change amount limiting unit 62 of FIG. 1, the open circuit voltage estimation method charge rate change amount ΔSOC _V is larger than the upper limit value vr ₁ (= current integration method charge rate differential value ΔSOC _C + predetermined value A) ( In the same figure, the state indicated by the arrow pointing upward to the right), the upper limit is limited with the open circuit voltage estimation method charging rate change amount ΔSOC _V as the upper limit value vr ₁ .
On the other hand, the open-circuit voltage estimation method charging rate change amount ΔSOC _V is smaller than the lower limit value vr ₂ (= current integration method charging rate differential value ΔSOC _C −predetermined value A) (in the state shown by the lower right broken arrow in the figure) ) When the open circuit voltage estimation method charging rate change amount ΔSOC _V is set as a lower limit value vr ₂ , the lower limit is limited.
Further, when the open-circuit voltage estimation method charging rate change amount ΔSOC _V is between the upper limit value vr ₁ and the lower limit value vr ₂ , the value is used without being limited.

In this way, the change amount restriction processing unit 6 changes the open-circuit voltage estimation method charging rate SOC _{V so} that the open-circuit voltage estimation method charging rate SOC _V is limited to the range between the upper limit value vr ₁ and the lower limit value vr _2. It is changed according to the amount ΔSOC _V and is output as the open circuit voltage estimation method limited charging rate SOC _vr . This open-circuit voltage estimation method limited charging rate SOC _vr is estimated to be the charging rate SOC of battery BT (SOC _vr = SOC).

  Next, the operation of the charging rate estimation device for the battery BT according to the first embodiment configured as described above will be described.

First, when the ignition key of the vehicle is turned to enable discharge from the battery BT, the charge / discharge current detection unit 1 detects the charge / discharge current i of the battery BT and the integrator 31 of the current integration method charge rate calculation unit 3. And output to the overvoltage calculation unit 42 of the open-circuit voltage estimation method charging rate calculation unit 4.
At the same time, the terminal voltage detection unit 2 detects the terminal voltage v of the battery BT, and the open voltage-charge rate calculation unit 32 of the current integration method charge rate calculation unit 3 and the open voltage estimation method charge rate calculation unit 4 Each is output to the subtracter 41.

In the current integration method charging rate calculation unit 3, the terminal voltage v detected by the terminal voltage detection unit 2 at the beginning of discharge is substantially close to the open circuit voltage OCV. The initial charge rate SOC _O is obtained, and the initial charge rate SOC ₀ is calculated by multiplying the full charge capacity FCC stored in the initial charge rate SOC _O, and the initial charge rate SOC ₀ is output to the integrator 31. The initial value of. The integrator 31 calculates the remaining capacity u ₁ of the battery BT at that time by integrating the charge / discharge current i input from the charge / discharge current detection unit 1 with time and adding it to the initial value.

On the other hand, the full charge capacity calculation unit 33 multiplies the soundness level SOH and the design capacity DC stored in advance to calculate the full charge capacity u ₂ at that time.
The capacity ratio calculation unit 34 calculates the current integration method SOC _C SOC by dividing the remaining capacity u ₁ obtained by the integrator 31 by the full charge capacity u ₂ obtained by the full charge capacity calculation unit 33. This value is output to the differentiator 51 of the variation limit value calculation unit 5.

In the change amount limit value calculation unit 5, the differentiator 51 z-converts and discretizes the current integration method charging rate SOC _C obtained by the capacity ratio calculation unit 34, and obtains the change amount by differentiation. The charging rate differential value ΔSOC _C which is the amount of change is added with a predetermined value A set by a predetermined value setting unit 52 by an adder 53 to set a change amount upper limit value vr ₁ , and a subtractor 54 variation lower limit value vr ₂ predetermined value A is subtracted is set. These change amount upper limit value vr ₁ and change amount lower limit value vr ₂ are output to the change amount restriction processing unit 6.

On the other hand, in the open circuit voltage estimation method charging rate calculation unit 4, the overvoltage calculation unit 42 detects the resistance R of the battery BT estimated by the open circuit estimation unit 43 using the battery equivalent circuit model and the charge / discharge current detected by the charge / discharge current detection unit 1. Multiply i to calculate the overvoltage v ₁ and output to the subtractor 41.

The subtracter 41 subtracts the overvoltage v ₁ from the terminal voltage v detected by the terminal voltage detection unit 2, to obtain the open circuit voltage OCV of the battery BT. The open-circuit voltage OCV is calculated by the open-circuit voltage-charge rate calculation unit 44 by referring to a lookup table of stored relational data between the open-circuit voltage OCV and the charge rate SOC and calculating the open-circuit voltage estimation method charge rate SOC _v. The data is output to the amount restriction processing unit 6.

In the change amount restriction processing unit 6, the input open circuit voltage estimation method charging rate SOC _v is differentiated by the differentiator 61 to obtain an open circuit voltage estimation method charging rate change amount ΔSOC _v . This open-circuit voltage estimation method charging rate change amount ΔSOC _v falls within the range between the upper limit value vr ₁ and the lower limit value vr ₂ set by the change amount limit value calculation unit 5 in the change amount limit unit 62. The upper limit and the lower limit are limited to an excessively large size.

That is, a short time in response to the variation [Delta] SOC _C current integration method charging rate SOC _C relative accuracy is obtained with excellent current integration method, the change amount [Delta] SOC _V open circuit voltage estimation charging rate SOC _V is restricted Even if the current state of the input signal (frequency component, noise, etc.) is low and the current state is low, the estimated charging rate may cause an abnormal transient response or the estimation result will hunt, resulting in a true charging rate. Suppresses large deviation from
In this case, since the upper and lower limit values vr ₁ and vr ₂ change according to the current integration method charging rate change amount ΔSOC _C , the absolute value of the charging rate SOC _V estimated by the open circuit voltage estimation method is excessive. As a result, it converges to a value that does not feel strange.

The charging rate estimation apparatus according to the first embodiment includes the current integration method charging rate SOC _C obtained by the current integration method charging rate calculation unit 3 as described above and the open circuit voltage estimation obtained by the open circuit voltage estimation method charging rate calculation unit 4. Based on the so-called sensor fusion technology that combines the method charge rate SOC _v and the upper and lower limit values vr ₁ and vr ₂ obtained by the change amount limit value calculation unit 6, the open-circuit voltage estimation method charge rate SOC _v By limiting the change amount ΔSOC _v by the change amount restriction processing unit 6, the open-circuit voltage estimation method limit charge rate SOC _vr , that is, the charge rate SOC of the battery BT is calculated.

In FIG. 3, the simulation result which estimated the charging rate using the charging rate estimation apparatus of the battery of Example 1 is shown.
In the figure, the uppermost row shows the current value i when an error is given to the sensitivity (gain = 0.9) of the charge / discharge current value i, and the middle row shows each charge when the current value i is given. Rate, that is, the true value of the charging rate SOC is a solid line, the current integration method charging rate SOC _C is a two-dot chain line, the open-circuit voltage estimation method charging rate SOC _V is a one-dot chain line, and the open-circuit voltage estimation method limited charging rate SOC _vr Is indicated by a dotted line, and the lowermost row shows an estimation error (absolute value) between each of the charging rates and the true value. In addition, the charging rate is calculated by the current integration method for 200 seconds from the start.
The estimation error of the open circuit voltage estimation method charging rate SOC _V is large and unstable during the period from the start of estimation to 1.2 × 10 ⁴ seconds, but the estimation error of the open circuit voltage estimation method limited charging rate SOC _vr is small and stable. It can be seen that the deviation of the estimation error is suppressed.

  As can be seen from the above description, the battery charge rate estimation apparatus of Embodiment 1 has the following effects.

That is, in the battery charging rate estimation device of the first embodiment, in estimating the charging rate SOC of the battery BT, the open-circuit voltage method charging rate SOC _V estimated by the open-circuit voltage estimation method is used as it is for the charging rate SOC of the battery BT. Instead of being used for estimation, the change amount ΔSOC _{V of the} open circuit voltage method SOC _V so that it falls within the range between the upper limit value vr ₁ and the lower limit value vr ₂ set by the change amount limit value calculation unit 5. The open-circuit voltage method limited charging rate SOC _vr obtained by limiting to the above is used.

In this case, the amount of change ΔSOC _C of the current integration method charging rate SOC _c has a higher estimation accuracy than the amount of change ΔSOC _V of the open circuit voltage method charging rate SOC _{V in} a short period of time. Therefore, the upper limit limit value vr ₁ and the lower limit limit value vr ₂ set according to the current integration method charge rate change amount ΔSOC _C are outside the range of these values, and the open-circuit voltage method charge rate change amount with low estimated reliability ΔSOC _V is limited to the above upper limit value or lower limit value, so that even in the case of a low current state, the estimated charging rate is increased immediately after the start of estimation or due to the state of the input signal (frequency component, noise, etc.). Suppresses a large deviation from the true charge rate due to abnormal transient response or hunting of estimation results. As a result, in the battery charging rate estimation device of the first embodiment, the estimation accuracy of the charging rate SOC of the battery BT is improved by using the sensor fusion technology using the current integration method charging rate SOC _c and the open-circuit voltage method charging rate SOC _V. While improving, the estimation error which occurs at this time can be suppressed small.

Further, in the change amount limit value calculation unit 5, the upper limit value vr ₁ and the lower limit value vr _{2 use} the current integration method charge rate change amount ΔSOC _C obtained by the current integration method charge rate calculation unit 3. The predetermined value A set by the predetermined value setting unit 52 is added by the adder 53 to obtain the upper limit value vr _1, and the predetermined value A is subtracted from the current integration method charging rate change amount ΔSOC _C by the subtractor 54. Since the limit value vr ₂ is obtained, the upper limit value vr ₁ and the lower limit value vr ₂ can be easily obtained with a simple configuration.

Next, a battery charge rate estimation apparatus according to Embodiment 2 of the present invention will be described with reference to the accompanying drawings.
In the description of the present embodiment, among the configurations of the second embodiment, the same components as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and the description thereof is omitted, and the differences are described. To do.

In the battery charge rate estimation apparatus of the second embodiment, the configuration of the variation limit calculation unit 7 is different from the configuration of the variation limit calculation unit 5 of the first embodiment.
That is, the variation limit calculation unit 7 includes a differentiator 71, a first multiplier 72, and a second multiplier 73.

The differentiator 71 has the same configuration as the differentiator 51 of the first embodiment, discretizes and differentiates the current integration method charging rate SOC _C input from the current integration method charging rate calculation unit 3, and the change amount ΔSOC _C is obtained. The obtained value is output to the first multiplier 72 and the second multiplier 73.

The first multiplier 72 multiplies the current integration method charging rate SOC _C input from the differentiator 71 by a predetermined value B to obtain an upper limit value vr ₁ ′. For example, the predetermined value B is set to 1.2 in this embodiment.
The second multiplier 73 multiplies the current integration method charging rate SOC _C input from the differentiator 71 by a predetermined value 1 / B to obtain a lower limit value vr ₂ ′.
The upper limit value vr ₁ ′ set by the first multiplier 72 and the lower limit value vr ₂ ′ set by the second multiplier 73 are each output to the variation limit processing unit 6.

As in the first embodiment, the change amount restriction processing unit 6 uses the change amount ΔSOC _V of the open circuit voltage estimation method SOC _V obtained by the differentiator 61 as shown in FIG. ₁ 'and the lower limit value vr _2' to limit so as not to exceed the scope of the.
Other configurations are the same as those of the first embodiment.

The operation of the battery charge rate estimation apparatus of the second embodiment is also the same as the setting of the upper limit value vr ₁ ′ and the lower limit value vr ₂ ′, but the addition / subtraction operation in the first embodiment is replaced with multiplication / division in the second embodiment. As a result, the operation is substantially the same as that of the first embodiment.

  As can be seen from the above description, the battery charging rate estimation apparatus according to the second embodiment can obtain the following effects.

That is, even in the battery charge rate estimation apparatus of the second embodiment, when estimating the charge rate SOC of the battery BT, the open-circuit voltage method charge rate SOC _V estimated by the open-circuit voltage estimation method is directly used as the charge rate SOC of the battery BT. Rather than being used for estimation, the change amount ΔSOC _{V of the} open circuit voltage method charging rate SOC _V is within the range between the upper limit value vr ₁ ′ and the lower limit value vr ₂ ′ set by the change amount limit value calculation unit 5. The open-circuit voltage method limited charging rate SOC _vr obtained by limiting to be within the range was used.

As a result, even in the case of a low current state, the estimated charging rate may cause an abnormal transient response or the estimation result may be hunted immediately after the estimation starts or due to the state of the input signal (frequency component, noise, etc.) Suppresses large deviation from the true charge rate. As a result, in the battery charge rate estimation apparatus of the second embodiment, the estimation accuracy of the charge rate SOC of the battery BT is improved by using the sensor fusion technology using the current integration method charge rate SOC _c and the open-circuit voltage method charge rate SOC _V. While improving, the estimation error which occurs at this time can be suppressed small.

Further, in the change amount limit value calculation unit 7, the upper limit value vr ₁ ′ and the lower limit value vr ₂ ′ use the current integration method charge rate change amount ΔSOC _C obtained by the current integration method charge rate calculation unit 3, This is multiplied by a predetermined value B by a first multiplier 72 to obtain an upper limit value vr ₁ ′, and the current integration method charging rate change amount ΔSOC _C is multiplied by a predetermined value 1 / B to obtain a lower limit value vr ₂ ′. Therefore, the upper limit value vr ₁ ′ and the lower limit value vr ₂ ′ can be easily obtained with a simple configuration.

Next, a battery charge rate estimation apparatus according to Embodiment 3 of the present invention will be described with reference to the accompanying drawings.
In the description of the present embodiment, among the configurations of the third embodiment, the same reference numerals as those in the first embodiment are assigned to the substantially same components as those in the first embodiment, and the description thereof is omitted, and differences are described. To do.

The charging rate estimation apparatus of Example 3 is shown in FIG. The present embodiment is different from the first embodiment in the following points.
That is, the current integration method charging rate calculation unit 3 has a current integration method variance calculation unit 35, the open-circuit voltage estimation method charge rate estimation unit 4 has an open-circuit voltage estimation method variance calculation unit 45, and the error correction unit 8 further has an error correction unit 8. This is a newly added point.

The current integration method variance calculation unit 35 performs a recursive matrix operation based on the information on the detection accuracy of the charge / discharge current detection unit 1 obtained in advance to obtain the current integration method variance Q _i and outputs it to the error correction unit 8. To do.
Similarly, based on the information regarding the detection accuracy of the charge / discharge current detection unit 1 and the terminal voltage detection unit 2 obtained in advance, the variance P _{OCV of the} open-circuit voltage is calculated, and the open-circuit voltage estimation method charge rate SOC _v is calculated based on this value. The variance (open-circuit voltage estimation method variance: P _SOCV = Q _v ) is calculated and output to the error estimator 8.

Error correction unit 8, a first subtractor 81, an error estimator 82, a second subtracter 83 has a calculates an error n _i of the current integration method charging rate SOC _C, current integration method it is intended to obtain a corrected charge rate SOC _CV removing the estimated error n _i from the current integration method charging rate SOC _C calculated by the charging rate calculating unit 3. The error correction unit 8 corresponds to a charging rate correction unit of the present invention.

The first subtracter 81 subtracts the current integration method charging rate SOC _C input from the current integration method charging rate calculation unit 31 from the open circuit voltage estimation method charging rate SOC _v input from the open circuit voltage estimation method charging rate estimation unit 4. The subtraction value y is output to the error estimation unit 82.

The error estimation unit 82 includes the current integration method variance Q _i input from the current integration method variance calculation unit 35 of the current integration method charging rate calculation unit 3 and the open-circuit voltage estimation method variance input from the open-circuit voltage estimation method estimation unit 4. and Q _v, the subtraction value y received from the first subtracter 81, based on estimates the estimation error n _i of the current integration method charging rate SOC _C using a Kalman filter, the output to the second subtractor 83 To do.

The Kalman filter in the error correction unit 8 compares the error estimated by the error model with the subtraction value y calculated by the first subtractor 81, and if there is a difference between them, this difference is multiplied by the Kalman gain and fed back. Then, the error model is corrected so that the error is minimized. This is repeated sequentially to estimate a true charging rate estimation error.
The details are described in Japanese Patent Application No. 2011-007874 by the present applicant as described above.

In the second subtractor 83, to obtain a corrected current integration method charging rate SOC _CV by subtracting the error n _i obtained by the error estimating section 82 from the current integration method charging rate SOC _C obtained from the current integration method charging rate calculating unit 3 , And output to the variation limit processing unit 6. The corrected current integration method SOC _CV corresponds to the corrected charge rate of the present invention.

In the variation limit processing unit 6, the correction current integration method charging rate SOC _CV obtained by the error correction unit 8 using the open-circuit voltage estimation method charging rate SOC _v and the upper limit limiting value vr ₁ obtained by the variation amount limiting value calculation unit 5. From the lower limit value vr ₂ , the current integration method limited charging rate SOC _cr, that is, the charging rate SOC of the battery BT is calculated by the same calculation as in the first embodiment.
Other configurations are the same as those of the first embodiment.

In the charging rate estimation device for battery BT of the third embodiment, in addition to the same effects as those of the first embodiment, the following effects can be obtained.
That is, in the charging rate estimation device for battery BT of the third embodiment, error correction unit 8 calculates corrected current integration method charging rate SOC _CV using open-circuit voltage estimation method charging rate SOC _v and current integration method charging rate SOC _c. Since it is obtained and input to the change amount restriction processing unit 6, it is possible to increase the estimation accuracy of the charging rate SOC of the battery BT accordingly.

Next, a battery charge rate estimation apparatus according to Embodiment 4 of the present invention will be described with reference to the accompanying drawings.
In the description of the present embodiment, among the configurations of the fourth embodiment, those substantially the same as those of the second embodiment are denoted by the same reference numerals as those of the second embodiment, and the description thereof is omitted, and differences are described. To do.

FIG. 6 shows a charging rate estimation apparatus according to the fourth embodiment. The present embodiment is different from the second embodiment in the following points.
That is, in the charging rate estimation device of the fourth embodiment, the error correction unit 8 of the third embodiment, the current integration method variance calculation unit 35 and the open circuit voltage designation method variance calculation unit 45 related thereto are added to the second embodiment. It is a thing.
Therefore, in the present embodiment, in addition to the same effects as those of the first embodiment, the following effects can be obtained.
In the battery BT charging rate estimation apparatus of the fourth embodiment, the error correction unit 8 obtains the corrected current integrating method charging rate SOC _CV using the open circuit voltage estimating method charging rate SOC _v and the current integrating method charging rate SOC _c , Since the change amount limit processing unit 6 is input, it is possible to increase the estimation accuracy of the charge rate SOC of the battery BT accordingly.

  The present invention has been described based on the above embodiments. However, the present invention is not limited to these embodiments, and is included in the present invention even when there is a design change or the like without departing from the gist of the present invention. .

  For example, the method for obtaining the initial value in the current integration method charging rate calculation unit 3 and the method for obtaining the open circuit voltage in the open circuit voltage estimation method charging rate calculation unit 4 may be different from those in the above embodiment.

  The predetermined values A and B used in the change amount limit value calculation units 5 and 7 are the predetermined value A1 for the adder 53, the predetermined value A2 (A2 ≠ A1) for the subtractor 54, and the first multiplier. A predetermined value B1 may be used for 72, and a predetermined value 1 / B2 (B2 ≠ B1) may be used for the second multiplier 73. Needless to say, the predetermined value can be set to 1 / B and the inverse thereof can be set to B.

Further, in the third and fourth embodiments, the error correction unit 8 estimates the error using the current integration method charging rate SOC _c and the open-circuit voltage estimation method charging rate to obtain the corrected current integration method charging rate SOC _CV , and changes The amount limit processing unit 6 uses the error correction unit 9 shown in FIG. 7 instead of the error correction unit 8 to obtain the corrected open-circuit voltage estimation method SOC _vv , and this value is used as the change amount limit processing unit. 6 may be input.

That is, the error correction unit 9 includes a first subtracter 91, an error estimation unit 92, and a second subtractor 93, and calculates an error n _V of the open circuit voltage estimation method charging rate SOC _V , it is intended to obtain the open-circuit voltage estimation method open circuit voltage estimation method to calculate the charging rate calculating unit 4 to remove the estimated error n _V from the charge rate SOC _V corrected charge rate SOC _vv. The error correction unit 9 corresponds to a charging rate correction unit of the present invention.

The first subtracter 91 subtracts the open-circuit voltage estimation method charging rate SOC _v input from the open-circuit voltage estimation method charging rate estimation unit 4 from the current integration method charging rate SOC _C input from the current integration method charging rate calculation unit 31. The subtraction value y is output to the error estimation unit 92.

The error estimation unit 92 includes the current integration method variance Q _i input from the current integration method variance calculation unit 35 of the current integration method charging rate calculation unit 3 and the open-circuit voltage estimation method variance input from the open-circuit voltage estimation method estimation unit 4. Based on Q _v and the subtraction value y input from the first subtractor 91, the estimation error n _v of the open-circuit voltage estimation method charging rate SOC _v is estimated using the Kalman filter, and the second subtracter 93 is estimated. Output.

In the second subtractor 93, the correction open circuit voltage estimation charging rate SOC by subtracting the error n _v obtained by the error estimating section 92 from the open circuit voltage estimation charging rate SOC _v obtained from Kaiho voltage estimation SOC calculator 4 _vv is obtained and output to the variation restriction processing unit 6. The variation restriction processing unit 6 calculates the open-circuit voltage method limited charge rate SOC _vr using the corrected open-circuit voltage estimation method charge rate SOC _vv, and _sets this value as the charge rate SOC of the battery BT. The corrected open-circuit voltage estimation method charging rate SOC _vv corresponds to the corrected charging rate of the present invention.

As described above, the error correction unit may obtain either the corrected open-circuit voltage estimation method charging rate SOC _vv or the corrected current integration method charging rate SOC _CV . This is because the error correction units 8 and 9 remove the estimation error obtained by using both the open circuit voltage estimation method charging rate SOC _v and the current integration method charging rate SOC _C. This is because it can be considered that both the method charging rate SOC _vv and the corrected current integration method charging rate SOC _CV are substantially the same.

BT battery 1 charge / discharge detection unit (charge / discharge detection means)
2 Terminal voltage detector (terminal voltage detector)
3 Current integration method charging rate calculation unit (current integration method charging rate calculation means)
31 integrator 32 open-circuit voltage-charge rate calculation unit 33 full-charge capacity calculation unit 34 capacity ratio calculation unit 35 current integration method variance calculation unit 4 open-circuit voltage estimation method charge rate calculation unit (open-circuit voltage estimation method charge rate calculation means)
41 Subtractor 42 Overvoltage Calculation Unit 43 Opening Estimation Unit 44 Opening Voltage-Charge Rate Calculation Unit 45 Opening Voltage Estimation Method Variance Calculation Unit 5 Change Limit Value Calculation Unit (Change Limit Value Calculation Means)
51 Differentiator 52 Predetermined Value Setting Unit 53 Adder 54 Subtractor 6 Change Amount Limiting Processing Unit (Change Amount Limiting Processing Unit)
61 Differentiator 62 Change Limiting Unit 7 Change Limit Limit Calculation Unit (Change Limit Limit Calculation Unit)
71 differentiator 72 first multiplier 73 second multiplier 8 error correction unit 81 first subtraction unit 82 error estimation unit 83 second subtraction unit 9 error correction unit 91 first subtraction unit 92 error estimation unit 93 second subtraction unit

Claims (5)

Charge / discharge current detecting means for detecting the charge / discharge current of the battery;
Terminal voltage detecting means for detecting the terminal voltage of the battery;
A current integration method charge rate calculation means for calculating a current integration method charge rate by integrating the charge / discharge current detected by the charge / discharge current detection means;
An open-circuit voltage estimation that estimates the open-circuit voltage of the battery from the charge-discharge current detected by the charge-discharge current detection unit and the terminal voltage detected by the terminal voltage detection unit, and calculates the open-circuit voltage estimation method charging rate from the open-circuit voltage Legal charging rate calculation means,
Change amount limit value for obtaining a current integration method charge rate change amount from the current integration method charge rate obtained by the current integration method charge rate calculation means, and calculating an upper limit value and a lower limit limit value from the current integration method charge rate change amount Calculation means;
Using the open-circuit voltage estimation method charging rate obtained by the open-circuit voltage estimation method charging rate, a charging rate change amount is obtained so that the charging rate change amount falls within the range between the upper limit value and the lower limit value. Change amount restriction processing means for calculating the charge rate of the battery by changing the open-circuit voltage estimation method charge rate by limiting the charge rate change amount to
A battery charge rate estimation device comprising: The battery charge rate estimation apparatus according to claim 1,
The change amount limit value calculating means sets the upper limit value and the lower limit value by adding and subtracting a predetermined value to the current integration method charging rate change amount, respectively.
An apparatus for estimating a charging rate of a battery. The battery charge rate estimation apparatus according to claim 1,
The change amount limit value calculating means sets the upper limit value and the lower limit value by multiplying the current integration method charging rate change amount by a predetermined value and a reciprocal of the predetermined value, respectively.
An apparatus for estimating a charging rate of a battery. The battery charge rate estimation apparatus according to any one of claims 1 to 3,
An error between them is estimated from the current integration method charging rate and the open-circuit voltage estimation method charging rate, and a value obtained by subtracting the error from one of the current integration method charging rate and the open-circuit voltage estimation method charging rate is a corrected charging rate. As an error correction means for inputting to the change amount restriction processing means as
The change amount restriction processing means calculates the charge rate of the battery using the corrected charge rate as the open-circuit voltage estimation method charge rate used in the change amount restriction processing means.
An apparatus for estimating a charging rate of a battery. Accumulate the charge / discharge current of the battery detected by the charge / discharge current detection means to calculate the current integration method charging rate,
Estimating the open-circuit voltage of the battery from the charge / discharge current and the terminal voltage detected by the terminal voltage detection means, calculating the open-circuit voltage estimation method charging rate from the open-circuit voltage,
Obtain the current integration method charge rate change amount from the current integration method charge rate, calculate the upper limit value and the lower limit value from the current integration method charge rate change amount,
Using the open-circuit voltage estimation method, the charge rate change amount is obtained, and the charge rate change amount is limited and opened so that the charge rate change amount falls within the range between the upper limit value and the lower limit value. Calculate the battery charge rate by changing the voltage estimation method charge rate,
A method for estimating a charging rate of a battery.

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