JP2006292559A - Charging rate estimating device for secondary cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a charging rate estimating device for secondary cells, capable of promptly making the estimated charging rate value to a correct value, even when operation is resumed in the condition while changing each parameter of the battery model, after a long passage of time from stopping the parameter estimating operation to operation resumption. <P>SOLUTION: The charging rate estimating device for secondary cell using applicable digital filter is equipped with a regulating means 7 which, during a predetermined period from the beginning of parameter estimation operation, regulates to make the parameter estimation rate in applicable digital filter 4 to be larger than the parameter estimation rate, after passage of the predetermined time from the beginning of parameter estimation operation. The regulating means can increase the parameter estimation rate, by regulating so as to enlarge the adjustable gain or reduce the time constant of the low-pass filter of a preprocessing filter means 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an apparatus for estimating a charging rate SOC (also referred to as a charged state) of a secondary battery.

As described in Patent Document 1 below, the relationship between the charging rate SOC of the secondary battery and the open circuit voltage V ₀ (terminal voltage at the time of energization interruption, also referred to as electromotive force or open circuit voltage) depends on the progress of deterioration and temperature. Therefore, the present charging rate can be accurately estimated by obtaining the open circuit voltage for the secondary battery in use. In Patent Document 1, the open circuit voltage V ₀ is estimated from the current I and the terminal voltage V of the secondary battery using an adaptive digital filter, and the charge rate SOC is calculated based on data measured in advance from the open circuit voltage V _0. Looking for.
Patent Document 2 below describes the contents of performing the charge rate estimation calculation using the value immediately before the cancellation (previous value) when the estimation calculation is resumed after the parameter estimation calculation is stopped.

JP 2004-178848 A JP 2004-077942 A

In the charging rate estimation device for the secondary battery using the applied digital filter as described above, the parameter estimation calculation is stopped in the configuration in which the charging rate estimation is performed using the value immediately before the cancellation as described in Patent Document 2. If the battery temperature or voltage due to self-discharge changes for a long time after the start of the calculation, that is, if the calculation is restarted with each parameter of the battery model changed, the estimated parameter is the true value from the start of the calculation. There is a problem that it takes time to follow the battery, and the charging rate of the battery cannot be accurately estimated.
The present invention solves the above problems and provides a secondary battery charge rate estimation device capable of quickly obtaining an accurate charge rate estimate value when estimation is resumed after stopping parameter estimation. Objective.

In order to achieve the above object, in the present invention, after a predetermined time elapses in the estimated speed of the parameter estimation calculation in the applied digital filter, for a predetermined time (time until the parameter follows the true value) from the start of the calculation. Or at least one of increasing the processing speed of the low-pass filter (decreasing the time constant).
In other words, at the time of startup after the interruption (at the start of calculation), the follow-up speed is more important than the suppression of the influence of noise, and other parameters are less likely to change greatly. Therefore, the suppression of the influence of noise is emphasized.

  Within a predetermined time from the start of calculation, the estimation speed of parameter estimation calculation is high or the processing speed of the low-pass filter is high (time constant is low), so the calculation resumes with each parameter of the battery model changed Even in this case, it is possible to quickly estimate the correct value of the battery parameter, and as a result, it is possible to accurately estimate and calculate the charging rate immediately after the start of the calculation, and the parameter estimation calculation Since the estimated speed and the processing speed of the low-pass filter are returned to the normal values, there is an effect that there is no possibility that the influence of noise becomes large during normal operation.

Example 1
FIG. 1 is a functional block diagram showing the configuration of an embodiment of the present invention.
As shown in FIG. 1, the present invention includes a current measuring means 1 for periodically detecting a current charged / discharged to a secondary battery, a voltage measuring means 2 for periodically detecting a terminal voltage of the battery, a current and a voltage. The pre-processing filter calculation means 3 for applying low-pass filter processing to the input, the adaptive digital filter calculation means 4 for estimating the battery parameters using the output of the pre-processing filter calculation means 3 as input, and the battery identified by the adaptive digital filter calculation means 4 The open circuit voltage calculation means 5 for estimating the open circuit voltage V ₀ from the parameters (K, K · T ₂ , T ₁ ) and the output of the preprocessing filter calculation means 3, the estimated open circuit voltage and the charge of the battery acquired in advance. A charge rate calculation means 6 for calculating the charge rate SOC based on the rate-open circuit voltage characteristics, an adaptive digital filter calculation means 4 and a pre-processing filter according to the difference in power-off time and battery temperature An adjusting means 7 for adjusting the response speed (adjustment gain) and time constant of the calculating means 3, a battery temperature detecting means 8 for measuring the battery temperature, and a battery temperature storing means 9 for storing the detected battery temperature (temperature difference in claims) And a power-off time detection means 10 (corresponding to the time-measurement means in the claims) for measuring the power-off time (elapsed time from the end of the previous calculation until the restart of the current calculation) It is composed of

FIG. 2 is a specific configuration diagram of an embodiment of the present invention. This embodiment shows an example in which a function for estimating and calculating a charging rate of a secondary battery is provided in a system in which a load such as a motor is driven by a secondary battery or a secondary battery is charged by regeneration of a motor. .
In FIG. 2, 20 is a secondary battery, 30 is a load of a motor, etc., 40 is an electronic control unit (battery controller) that estimates the charging rate, full charge capacity, etc. of the secondary battery. And a microcomputer composed of a ROM and a RAM for storing calculation results and an electronic circuit. 50 is a current sensor that detects current charged and discharged from the battery, 60 is a voltage sensor that detects battery terminal voltage (also simply referred to as voltage), 70 is a temperature sensor that detects battery temperature, and 80 is power off time measurement. The power-off time measuring timers are connected to the electronic control unit 40, respectively. The electronic control unit 40 corresponds to the preprocessing filter calculation means 3, the adaptive digital filter calculation means 4, the open circuit voltage calculation means 5, the charging rate calculation means 6, and the adjustment means 7 of FIG. The current sensor 50 corresponds to the current measuring means 1, the voltage sensor 60 corresponds to the voltage measuring means 2, the temperature sensor 70 corresponds to the battery temperature detecting means 8, and the power OFF time measuring timer 80 corresponds to the power OFF time detecting means 10. . The battery temperature storage means 9 in FIG. 1 corresponds to a memory (not shown) in the electronic control unit 40 in FIG.

First, a method for estimating an open circuit voltage and a charging rate using the adaptive digital filter will be described.
In this embodiment, the battery model of the secondary battery is defined as shown in the following (formula 6) (equation 1), and the open circuit voltage V ₀ is obtained using the battery model (continuous time system) of the formula (6). Is approximated by Equation (7) (= Equation 2), Equation (6) is changed to Equation (8) (= Equation 3), and low-pass filter processing is performed on both sides of Equation (8). An adaptive digital filter operation is performed on the obtained Equation (9) (= Equation 4), the coefficient parameters of A (s) and B (s) and the variable d are collectively estimated, and then, instead of Equation (7) Substituting the estimated coefficient parameters of A (s) and B (s) into the following equation (equation 10) equivalent to equation (6) (equation 5) to calculate G _LPF (s) · V ₀ This is used as a substitute for the open circuit voltage V ₀ . The charging rate is estimated from the relationship between the known open circuit voltage V ₀ and the charging rate SOC.

ｓ：ラプラス演算子 Ａ(ｓ)、Ｂ(ｓ)：ｓの多項式（ｎは次数）
Ｉ：電流 Ｖ：電圧 Ｖ_０：開路電圧
Ｇ_ＬＰＦ(ｓ)：ローパスフィルタの伝達特性（次数差はｎ＋１以上）。

s: Laplace operator A (s), B (s): polynomial of s (n is the degree)
I: current V: voltage V ₀ : open circuit voltage G _LPF (s): transfer characteristic of low-pass filter (order difference is n + 1 or more).

FIG. 3 is a circuit diagram showing a battery model used for the above estimation. In FIG. 3, the input to the model is current I [A] (positive value: charge, negative value: discharge), and the output is terminal voltage V [V], open circuit voltage V ₀ [V] (also referred to as electromotive force or open voltage). R ₁ is a charge transfer resistance, R ₂ is a pure resistance, and C ₁ is an electric double layer capacitance. Although this model is a reduction model (primary) in which the positive electrode and the negative electrode are not particularly separated, it is possible to show the actual charge / discharge characteristics of the battery relatively accurately.
This battery model can be expressed by Equation (11). Note that s is a Laplace operator.

上記（数１１）式を変形すると下記（数１２）式になる。

When the above equation (11) is modified, the following equation (12) is obtained.

開路電圧Ｖ_０は、電流Ｉに可変な効率ｄを乗じたものを、ある初期状態から積分したものと考えれば、下記（数１３）式で示すことが出来る。

The open circuit voltage V ₀ can be expressed by the following equation (13) when it is considered that the current I multiplied by the variable efficiency d is integrated from a certain initial state.

（数１３）式を（数１２）式に代入すれば（数１４）式になり、整理すれば（数１５）式になる。

Substituting equation (13) into equation (12) yields equation (14), and organizing it yields equation (15).

安定なローパスフィルタＧ_ＬＰＦ(ｓ）を（数１５）式の両辺に乗じ、整理すれば（数１６）式になる。

When a stable low-pass filter G _LPF (s) is multiplied by both sides of the equation (15) and rearranged, the equation (16) is obtained.

実際に計測可能な電流Ｉや端子電圧Ｖを、ローパスフィルタやバンドパスフィルタ（図１の前処理フィルタ演算手段３）で処理した値を下記（数１７）式のように定義する。

A value obtained by processing the current I and the terminal voltage V that can be actually measured by a low-pass filter or a band-pass filter (preprocessing filter calculation means 3 in FIG. 1) is defined as the following equation (17).

上記（数１７）式で示す変数を用いて（数１６）式を書き直せば、（数１８）式になる。

If the equation (16) is rewritten using the variable shown in the equation (17), the equation (18) is obtained.

（数１８）式を更に変形すれば、（数１９）式になる。

If Formula (18) is further modified, Formula (19) is obtained.

ただし、Ｖ_３＝ｓ^２・Ｇ_ＬＰＦ(ｓ)・Ｖ
Ｖ_２＝ｓ・Ｇ_ＬＰＦ(ｓ)・Ｖ
Ｉ_３＝ｓ^２・Ｇ_ＬＰＦ(ｓ)・Ｉ
Ｉ_２＝ｓ・Ｇ_ＬＰＦ(ｓ)・Ｉ
Ｉ_１＝Ｇ_ＬＰＦ(ｓ)・Ｉ
上記のように、電池モデルの次数を１次に限定することで、前記（数６）式、（数８）式、（数９）式は、それぞれ（数１２）式、（数１５）式、（数１９）式に対応することになる。
（数１９）式は、計測可能な値と未知パラメータの積和式になっているので、一般的な適応デジタルフィルタの標準形（数２０）式と一致する。

However, V ₃ = s ² · G _LPF (s) · V
V ₂ = s · G _LPF (s) · V
I ₃ = s ² · G _LPF (s) · I
I ₂ = s · G _LPF (s) · I
I ₁ = G _LPF (s) · I
As described above, by limiting the order of the battery model to the first order, the above (Expression 6), (Expression 8), and (Expression 9) are expressed by (Expression 12) and (Expression 15), respectively. , (Expression 19).
Since (Equation 19) is a product-sum expression of a measurable value and an unknown parameter, it agrees with a standard form (Equation 20) of a general adaptive digital filter.

ただし、
ｙ＝Ｖ_２、ω^Ｔ＝［Ｖ_３，Ｉ_３，Ｉ_２，Ｉ_１］、θ^Ｔ＝［−Ｔ_１，Ｋ・Ｔ_２，Ｋ，ｄ］
である。
従って、電流Ｉと端子電圧Ｖにフィルタ処理を施した信号を、適応デジタルフィルタ演算に用いることで、未知パラメータベクトルθを推定することが出来る。

However,
y = V ₂ , ω ^T = [V ₃ , I ₃ , I ₂ , I ₁ ], θ ^T = [− T ₁ , K · T ₂ , K, d]
It is.
Therefore, the unknown parameter vector θ can be estimated by using a signal obtained by filtering the current I and the terminal voltage V in the adaptive digital filter calculation.

The present embodiment has improved the logical disadvantage of a simple “adaptive digital filter based on the least squares method”, that is, once the estimated value has converged, accurate estimation cannot be performed again even if the parameter changes thereafter. "Limit trace gain method" is used.
A sequential estimation algorithm for estimating the unknown parameter vector θ based on the above equation (20) is as shown in the following equation (21). However, the parameter estimated value at the time point k is assumed to be θ (k).

ここで、λ_１、λ_３、γ_Ｕ、γ_Ｌは初期設定値で、０＜λ_１＜１、０＜λ_３＜∞とする。Ｐ(０）は十分大きな値、θ(０）は非ゼロな十分小さな値を初期値とする。trace｛Ｐ｝は行列Ｐのトレースを意味する。λ_３は適応デジタルフィルタの推定演算の応答速度を設定する定数（調整ゲイン）であり、値を大きくすることにより応答速度は速くなるが、その反面ノイズの影響を受けやすくなる。なお、詳細な設定方法については後述する。

Here, λ ₁ , λ ₃ , γ _U and γ _L are initial setting values, and 0 <λ ₁ <1 and 0 <λ ₃ <∞. P (0) is a sufficiently large value, and θ (0) is a non-zero and sufficiently small value. trace {P} means tracing of the matrix P. lambda ₃ is a constant (adjustment gain) to set the response speed of the estimation calculation of the adaptive digital filter, the response speed is faster by increasing the value becomes susceptible to the contrary noise. A detailed setting method will be described later.

Next, processing performed by the microcomputer of the electronic control unit 40 will be described with reference to the flowchart shown in FIG. Note that the routine shown in the figure is executed every fixed period T ₀ , where I (k) represents the current value and I (k−1) represents the previous value.
In FIG. 5, in step S10, a current I (k), a terminal voltage V (k), and a battery temperature T _B (k) are measured. The battery temperature T _B (k) is stored in a memory with a backup function that retains the stored contents even when the power source of the electronic control unit 40 is shut off.

In step S20, the time t _OFF during which the electronic control unit 40 has been turned off, as measured by the power off time measurement timer 80, is input. The power OFF time t _OFF need only be input once at the start of calculation.
In step S30, the state of the cutoff relay of the secondary battery is determined. The battery electronic control unit 40 also controls the secondary battery cutoff relay. When the relay is cutoff (current I = 0), the process proceeds to step S40. When the relay is engaged, the process proceeds to step S50.

In step S40, the terminal voltage V (k) is stored as the terminal voltage initial value V_ini. Further, the value θ (−1) immediately before the power is turned off is substituted for the parameter estimated value θ (0).
In step S50, the terminal voltage difference value ΔV (k) is calculated based on the following equation.
ΔV (k) = V (k) −V_ini
In step S60, it sets an adjustment gain lambda ₃ and the low pass filter time constant p of the adaptive digital filter from the power Off time _{t OFF} and the battery temperature _{T B.} Details will be described later.

In step S70, the low-pass filter and the band-pass filter are processed based on the following equation (22) using the time constant p set in step S60 for the current I (k) and the terminal voltage difference value ΔV (k). And calculate I _{1 to} I ₃ and V _{1 to} V ₃ .

実際には、タスティン近似などで離散化して得られた漸化式を用いて演算する。
ステップＳ８０では、ステップＳ７０で算出したＩ_１〜Ｉ_３、Ｖ_２〜Ｖ_３およびステップＳ６０で算出した調整ゲインλ_３を前記（数２１）式に代入し、パラメータ推定値θ(ｋ）を算出する。
ただし、
ｙ＝Ｖ_２、ω^Ｔ［Ｖ_３，Ｉ_３，Ｉ_２，Ｉ_１］、θ^Ｔ＝［−Ｔ_１，Ｋ・Ｔ_２，Ｋ，ｄ］
である。

Actually, the calculation is performed using a recurrence formula obtained by discretization by Tustin approximation or the like.
In step S80, I _{1 to} I ₃ and V _{2 to} V ₃ calculated in step S70 and the adjustment gain λ ₃ calculated in step S60 are substituted into the equation (21) to calculate the parameter estimated value θ (k). To do.
However,
y = V ₂ , ω ^T [V ₃ , I ₃ , I ₂ , I ₁ ], θ ^T = [− T ₁ , K · T ₂ , K, d]
It is.

In step S90, T ₁ , K · T ₂ , K, and I _{1 to} I ₂ and V _{1 to} V calculated by the above equation (22) from the parameter estimated value θ (k) calculated in step S100. ₂ is substituted into the following (Equation 23) to calculate the open circuit voltage ΔV ₀ ′.

この（数２３）式は電池モデル（数１２式）を変形し、ローパスフィルタＧ_ＬＰＦ(ｓ）を両辺に乗じた式であるため、実際には開路電圧△Ｖ_０に対しローパスフィルタを施した値である。しかしながら開路電圧は変化が緩やかなので△Ｖ_０を△Ｖ_０’＝Ｇ_ＬＰＦ(ｓ)・△Ｖ_０で代用できる。
ただし、ここで求まるのは推定演算開始時からの開路電圧推定値の変化分△Ｖ_０(ｋ）であるため、後段のステップＳ１００で初期値を加算する。

Since the equation (Equation 23) is an equation obtained by modifying the battery model (Equation 12) and multiplying both sides by the low-pass filter G _LPF (s), the low-pass filter is actually applied to the open circuit voltage ΔV ₀ . Value. However the open circuit voltage is the change is gradual and △ _{V 0} △ _{V 0 '=} can be replaced by _{G LPF (s) · △ V} 0.
However, since what is obtained here is the change ΔV ₀ (k) of the open circuit voltage estimated value from the start of the estimation calculation, the initial value is added in step S100 in the subsequent stage.

In step S100, an open circuit voltage initial value, that is, a terminal voltage initial value V_ini, is added to ΔV ₀ ′ (k) calculated in step S90 to calculate an open circuit voltage estimated value V ₀ (k) from the following equation.
V ₀ (k) = ΔV ₀ '(k) + V_ini
In step S110, the charging rate SOC (k) is calculated from V ₀ (k) calculated in step S100 using the correlation map between the open circuit voltage and the charging rate shown in FIG.
In FIG. 4, V _L is an open circuit voltage corresponding to SOC = 0%, and V _H is an open circuit voltage corresponding to SOC = 100%.

In step S120, the total capacity _Qmax (k) is calculated from the charging rate SOC (k) and current I (k) calculated in step S110. As the method, for example, as shown in the following (Equation 24), the current I (k) can be divided by the differential value of the estimated charge rate.

ステップＳ１３０では、次回の演算に必要な数値を保存して、今回演算を終了する。

In step S130, numerical values necessary for the next calculation are stored, and the current calculation is terminated.

Next, a method for setting the adjustment gain λ ₃ and the low-pass filter time constant p will be described with reference to the flowchart shown in FIG.
6, at step S601, calculates the deviation △ _{T B} of the battery temperature _{T B} at the time of startup (0) and the power supply Off shortly before the battery temperature _{T B} (-1).
In step S602, using the temperature deviation ΔT _B and the power OFF time t _OFF , a time t _HOSEI for permitting correction of the adjustment gain and the time constant is set based on the following equation (25).
t _HOSEI = t _{temp_HOSEI} + t _{OFF_HOSEI} ( _Equation 25)
However, t _{temp_HOSEI} and t _{OFF_HOSEI} are set based on the maps shown in FIGS. In FIG. 7, the horizontal axis △ Temp shows the temperature difference △ T _B.

As can be seen from FIGS. 7 and 8, the values of t _{temp_HOSEI} and t _{OFF_HOSEI increase} as the temperature deviation and the power OFF time increase. That is, a large temperature deviation means that the battery parameter has changed significantly since the previous interruption, and a large power OFF time means that the battery parameter may have a large change. Therefore, in such a case, it is expected that the time until the parameter follows the true value will be longer. Therefore, the values of t _{temp_HOSEI} and t _{OFF_HOSEI} are increased as the temperature deviation and the power OFF time are increased.

In step S603, it is determined whether the time t _HOSEI set in step S602 has elapsed from the start (start-up) of calculation. If the predetermined time has not elapsed, the process proceeds to step S604, and if it has elapsed, the process proceeds to step S606.

At step S604, the calculating an adjustment gain correction coefficient _{K Temp_ramuda3} and low pass filter time constant correction factor _{K Temp_P} temperature deviations from the battery temperature deviation △ _{T B.} Actually, for example, calculation is performed using maps as shown in FIGS. In FIGS. 9 and 10, ΔTemp on the horizontal axis indicates a temperature deviation ΔT _B. Moreover, each correction coefficient may be changed stepwise depending on whether the battery temperature deviation △ T _B is equal to or higher than a predetermined value.

9, as shown in FIG. 10, the relationship between the correction coefficient _{K Temp_ramuda3} and the battery temperature deviation △ _{T B} is as the temperature difference is large correction coefficient _{K Temp_ramuda3} become a large value, adjusting the larger temperature difference It is corrected so as to increase the value of the gain lambda _3. The relationship between the correction coefficient K _{Temp_P} and the battery temperature deviation △ T _B, the higher the temperature difference is larger correction coefficient K _{Temp_P} and becomes a small value, so as to reduce the value of time constant p as the temperature deviation is greater It is corrected.
As described above, the larger the temperature deviation, the larger the adjustment gain and the smaller the time constant, thereby shortening the time for which the parameter follows the true value.

At step S605, it calculates the adjustment gain correction coefficient _{K TOFF_ramuda3} and low pass filter time constant correction factor _{K TOFF_P} corresponding to the power OFF time from the power OFF time _{t OFF.} Actually, for example, calculation is performed using maps as shown in FIGS.
Each correction coefficient may be changed stepwise depending on whether the power OFF time is equal to or greater than a predetermined value.

11, as shown in FIG. 12, the correction factor is the relationship between the _{K TOFF_ramuda3} and the power OFF time _{t OFF,} and as the correction factor _{K TOFF_ramuda3} large power OFF time _{t OFF} becomes a large value, the power supply OFF time t _OFF is higher is corrected so as to increase the value of the adjustment gain lambda ₃ large. The relationship between the correction coefficient _{K TOFF_P} and power OFF time _{t OFF,} the power OFF and the larger the time _{t OFF} correction coefficient _{K TOFF_P} becomes a small value, the value of the constant p when the larger power OFF time _{t OFF} It is corrected to make it smaller.
As described above, the adjustment gain is increased and the time constant is decreased as the power OFF time is increased, thereby shortening the time for the parameter to follow the true value.

In step S606, since a predetermined time has elapsed, the correction coefficients K _{temp — λ3} , K _{temp — P} , K _{tOFF — λ3} , and K _{tOFF — P} are all set to 1 and the correction is completed.
In step S607, the adjustment gain basic value λ _{3 — BASE} and the time constant basic value p _BASE are corrected based on the following formula (Equation 26) to calculate the final adjustment gain λ ₃ and the time constant p.
λ ₃ = K _{temp_λ3} · K _{tOFF_λ3} · λ _{3_BASE}
... (Equation 26)
p = K _{temp_P} · K _{tOFF_P} · p _BASE
It should be noted that only the adjustment gain λ ₃ or only the time constant p may be corrected in the processing content described so far in the flowchart.

Further, in the above description, when the calculation is restarted from the time when the power is turned off, the case where the values of the adjustment gain λ ₃ and the time constant p are all corrected has been explained. However, when the temperature deviation is small or the power off time is short. In this case, since the parameter variation is small and the correction is small, the correction is performed only when the battery temperature deviation ΔT _B is larger than the predetermined value and when the power OFF time t _OFF is larger than the predetermined value. May be. In this case, in the characteristics shown in FIGS. 7 and 8, the correction time t _{temp_HOSEI} and the correction time t _{OFF_HOSEI} may be set to 0 in the range where the temperature deviation and the power OFF time are smaller than a predetermined value. .

Next, the effect of the present invention will be described by simulation.
FIGS. 13 and 14 are examples of simulations showing the effect of the present invention, FIG. 13 shows the characteristics of the conventional example, and FIG. 14 shows the characteristics of the present invention.
The characteristic shown in the figure is that the power is temporarily turned off at a battery temperature of 0 ° C., restarted at a battery temperature of 25 ° C. after a time of 180 [sec], and thereafter the current is periodically (stepped) ± The result when 80 A is changed is shown.
In the conventional example of FIG. 13, the adjustment gain λ ₃ = 0.002 is fixed. Further, in the present invention shown in FIG. 14, only correction by temperature deviation is performed, and the correction coefficient K _temp — _λ3 = 20 at a temperature deviation of 25 ° C.

In the conventional example, since importance is placed on suppressing the influence of noise, the adjustment gain is fixed at a relatively low value (λ ₃ = 0.002), and therefore, T ₁ and K · T at the time of restart The delay until the battery parameter ₂ follows the true value is large, and as a result, the estimation accuracy of the charge rate SOC is also deteriorated.

On the other hand, in the present invention, since the adjustment gain is corrected to be higher (λ ₃ = 0.002 × 20) by the correction coefficient K _{temp — λ3 at} a temperature deviation of 25 ° C., the parameters T ₁ and K · T ₂ are quickly true. As a result, the estimation error of the charging rate SOC is also reduced. Since the adjustment gain returns to a normal value after a predetermined time, the influence of noise can be suppressed.

  As described above, in the present invention, the adjustment gain is increased within a predetermined time from the start of calculation. Therefore, even when the parameter fluctuates due to a change in battery temperature or the like when the power is turned off, the battery parameter can be estimated quickly. As a result, the charging rate and the like can be accurately estimated and calculated immediately after the calculation is started.

  In addition, since the time constant is reduced within a predetermined time from the start of calculation, the delay in the output of the preprocessing filter, which is the input of the adaptive digital filter, is reduced, so that the battery parameter estimation speed can be improved. Therefore, the charging rate and the like can be estimated and calculated with high accuracy immediately after the calculation is started.

  In addition, although the battery parameter depends on the temperature, even when the battery temperature deviation is large, that is, even when the battery parameter fluctuates greatly since the power is turned off, the parameter can be estimated quickly, and as a result, the internal state of the battery can be accurately determined. An estimation calculation can be performed.

  Further, even when the power OFF time is long, that is, when battery parameter fluctuation is expected, the parameter can be estimated quickly, and as a result, the battery internal state can be estimated and calculated with high accuracy. .

The functional block diagram which shows the structure of one Example of this invention. The specific block diagram of one Example of this invention. The circuit diagram which shows the battery model used for a charging rate estimation. The characteristic view which shows the relationship between an open circuit voltage and a charging rate. The flowchart which shows the calculation process of the charging rate estimation in this invention. The flowchart which shows the calculation process of the correction coefficient of adjustment gain (lambda) ₃ and the low-pass filter time constant p. FIG. 6 is a map characteristic diagram showing a relationship between a temperature deviation for setting a time t _HOSEI for performing correction for an adjustment gain and a time constant and a correction time t _{temp_HOSEI} . FIG. 7 is a map characteristic diagram showing a relationship between a power OFF time and a correction time t _{OFF_HOSEI} for setting a time t _HOSEI for performing correction for an adjustment gain and a time constant. The characteristic view of the map for calculating the adjustment gain correction coefficient _{Ktemp_ (lambda) 3} for a temperature deviation. The characteristic view of the map for calculating the time constant correction coefficient _{Ktemp_P} for a temperature deviation. The characteristic view of the map for calculating the adjustment gain correction coefficient _{KtOFF_λ3} for the power OFF time. The characteristic diagram of the map for calculating the time constant correction coefficient _{KtOFF_p} for power supply OFF time. It is a figure which shows an example of the simulation result for demonstrating the effect of this invention, and is a figure which shows the characteristic of a prior art example. It is a figure which shows an example of the simulation result for demonstrating the effect of this invention, and is a figure which shows the characteristic of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Current measurement means 2 ... Voltage measurement means 3 ... Pre-processing filter calculation means 4 ... Adaptive digital filter calculation means 5 ... Open circuit voltage calculation means 6 ... Charge rate calculation means 7 ... Adjustment means 8 ... Battery temperature detection means 9 ... Battery temperature Storage means 10 ... Power OFF time detection means 20 ... Secondary battery 30 ... Load 40 ... Electronic control unit 50 ... Current sensor 60 ... Voltage sensor 70 ... Temperature sensor 80 ... Power OFF measurement timer

Claims (12)

Current detecting means for detecting the current I of the secondary battery;
A terminal voltage detecting means for detecting a terminal voltage V of the secondary battery;
A parameter estimation calculation means for defining a battery model of the secondary battery, performing an adaptive digital filter calculation using the battery model, and collectively estimating the parameters of the battery model;
An open circuit voltage calculating means for calculating an open circuit voltage V ₀ from the detected values of the current I and the terminal voltage V and the estimated value of the parameter;
A charge rate calculating means for calculating a charge rate from the open circuit voltage V ₀ ,
Adjusting means for adjusting the parameter estimation speed in the parameter estimation calculation means so as to be larger than the parameter estimation speed after a lapse of the predetermined time from the start of the parameter estimation calculation for a predetermined time after the start of the parameter estimation calculation. An apparatus for estimating a charging rate of a secondary battery. Current detecting means for detecting the current I of the secondary battery;
A terminal voltage detecting means for detecting a terminal voltage V of the secondary battery;
A parameter estimation calculation means for defining a battery model of the secondary battery, performing an adaptive digital filter calculation using the battery model, and collectively estimating the parameters of the battery model;
An open circuit voltage calculating means for calculating an open circuit voltage V ₀ from the detected values of the current I and the terminal voltage V and the estimated value of the parameter;
A charge rate calculating means for calculating a charge rate from the open circuit voltage V ₀ ,
Pre-processing filter means for performing low-pass filter processing on the detected values of the current I and the terminal voltage V and then sending them to the parameter estimation calculation means;
Adjusting means for adjusting the processing speed of the low-pass filter to be larger than the processing speed of the low-pass filter after the predetermined time has elapsed from the start of the parameter estimation calculation for a predetermined time after the start of the parameter estimation calculation. An apparatus for estimating a charging rate of a secondary battery. The charging rate estimation device for a secondary battery according to claim 2,
The adjusting means sets the processing speed of the low-pass filter for a predetermined time after the start of parameter estimation calculation in the parameter estimation calculation means to be higher than the processing speed of the low-pass filter after the predetermined time has elapsed from the start of parameter estimation calculation. A charging rate estimation device for a secondary battery, configured to be larger and to make a parameter estimation speed in the parameter estimation calculation means larger than a parameter estimation speed after the predetermined time has elapsed from the start of parameter estimation calculation.   The parameter estimation speed in the parameter estimation calculation means is changed by adjusting the magnitude of the adjustment gain of the adaptive digital filter from the adjustment gain after the predetermined time has elapsed from the start of the parameter estimation calculation for a predetermined time after the parameter estimation calculation starts. The charging rate estimation device for a secondary battery according to claim 1, wherein the charging rate estimation device is further increased.   The processing speed of the low-pass filter is changed by making the time constant of the low-pass filter smaller than the time constant after the predetermined time has elapsed from the start of the parameter estimation calculation for a predetermined time after the parameter estimation calculation starts. The charging rate estimation apparatus for a secondary battery according to claim 2, wherein the charging rate estimation apparatus performs the charging process according to claim 2.   A temperature difference detecting means for detecting a difference between the temperature of the secondary battery at the start of the parameter estimation calculation of the parameter estimation calculation means and the temperature of the secondary battery at the time when the previous parameter estimation calculation was interrupted; 5. The adjustment gain according to claim 1, wherein the adjustment gain during a predetermined time after the start of the parameter estimation calculation is increased as the temperature difference detected by the temperature difference detection unit increases. Secondary battery charge rate estimation device.   A timing unit that detects an elapsed time from the time when the parameter estimation calculation was interrupted to the start of the parameter estimation calculation, and the adjustment unit has a longer elapsed time detected by the timing unit after the start of the parameter estimation calculation. 5. The secondary battery charge rate estimation apparatus according to claim 1, wherein the adjustment gain is increased during a predetermined period of time. Temperature difference detection means for detecting the difference between the temperature of the secondary battery at the start of parameter estimation calculation of the parameter estimation calculation means and the temperature of the secondary battery at the time when the previous parameter estimation calculation was interrupted, and interrupted the previous parameter estimation calculation Comprising at least one of time measuring means for detecting an elapsed time from the time when the parameter estimation calculation is started,
The adjusting means has a predetermined time after the start of the parameter estimation calculation when the temperature difference detected by the temperature difference detecting means is not less than a predetermined temperature difference or the elapsed time measured by the time measuring means is not less than a predetermined time. The magnitude of the adjustment gain during the period is made larger than the magnitude of the adjustment gain after the predetermined time has elapsed from the start of the parameter estimation calculation. Secondary battery charge rate estimation device.   A temperature difference detecting means for detecting a difference between the temperature of the secondary battery at the start of the parameter estimation calculation of the parameter estimation calculation means and the temperature of the secondary battery at the time when the previous parameter estimation calculation was interrupted; 4. The time constant of the low-pass filter during a predetermined time after the start of the parameter estimation calculation is decreased as the temperature difference detected by the temperature difference detection unit is larger. The charging rate estimation apparatus of the secondary battery as described in 5.   A timing unit that detects an elapsed time from the time when the parameter estimation calculation was interrupted to the start of the parameter estimation calculation, and the adjustment unit has a longer elapsed time detected by the timing unit after the start of the parameter estimation calculation. 6. The secondary battery charge rate estimation apparatus according to claim 2, wherein the time constant of the low-pass filter during a predetermined time is reduced. Temperature difference detection means for detecting the difference between the temperature of the secondary battery at the start of parameter estimation calculation of the parameter estimation calculation means and the temperature of the secondary battery at the time when the previous parameter estimation calculation was interrupted, and interrupted the previous parameter estimation calculation Comprising at least one of time measuring means for detecting an elapsed time from the time when the parameter estimation calculation is started,
The adjusting means has a predetermined time after the start of the parameter estimation calculation when the temperature difference detected by the temperature difference detecting means is not less than a predetermined temperature difference or the elapsed time measured by the time measuring means is not less than a predetermined time. 6. The secondary battery according to claim 2, wherein the time constant during the period is made smaller than the time constant after the predetermined time has elapsed from the start of the parameter estimation calculation. Charging rate estimation device. In the rechargeable battery charge rate estimating device according to any one of claims 1 to 11,
The parameter estimation calculation means defines the battery model of the secondary battery as shown in the following (formula 1), and the open circuit voltage V ₀ is expressed by the following formula (2) using the battery model of the formula (1). By approximating (Equation 1) to (Equation 3) and performing low-pass filter processing on both sides of (Equation 3), adaptive digital filter computation is performed on (Equation 4), A parameter parameter and a variable d of A (s) and B (s) are collectively estimated,
The open circuit voltage calculation means calculates the open circuit voltage V ₀ by substituting the detected values of the current I and the terminal voltage V and the estimated values of the parameters into the following equation (equation 5) equivalent to the equation (equation 1). Is,
The charging rate calculating means is that the open-circuit voltage V ₀ measured in advance determine the charging rate from the open-circuit voltage V ₀ based on the relationship between the charging rate, charging rate estimating device for a secondary battery, characterized by .

s: Laplace operator A (s), B (s): polynomial of s (n is the degree)
I: current V: voltage V ₀ : open circuit voltage G _LPF (s): transfer characteristic of low-pass filter (order difference is n + 1 or more)

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