JP2010210457A - Control device of secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device of a secondary battery capable of properly detecting a failure of a current detecting means and a voltage detecting means. <P>SOLUTION: The control device of the secondary battery includes: the current detecting means 301 for detecting current of the secondary battery; the voltage detecting means 302 for detecting terminal voltage of the secondary battery; an internal state estimating means 303 for estimating an internal state of the secondary battery from measurement values of the current and the terminal voltage detected by the current detecting means and the voltage detecting means; and failure detecting means 304, 305 and 306 for detecting failures of the current detecting means and the voltage detecting means based on the internal state of the secondary battery estimated by the internal state estimating means. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a control device for a secondary battery.

  As a control device for a secondary battery, when the voltage of the secondary battery fluctuates by a predetermined reference fluctuation amount, the current fluctuation amount is estimated based on the internal resistance of the secondary battery, and the obtained current fluctuation amount There is known a control device that detects an intermediate sticking failure of a current detection unit such as a current sensor by comparing the estimated value of the current value and a detected value of a fluctuation amount of a current detected by a current detection unit such as a current sensor. (For example, refer to Patent Document 1).

Japanese Patent Laid-Open No. 9-60899

  However, in the above prior art, even if not only the current detection unit but also the voltage detection unit fails, the estimated value of the current fluctuation amount does not correspond to the detection value of the current fluctuation amount. There is a problem that it is impossible to determine which of the means and the voltage detecting means is out of order.

  The problem to be solved by the present invention is to provide a control device for a secondary battery capable of appropriately detecting a failure of the current detection means and the voltage detection means.

  The present invention detects the current and terminal voltage of the secondary battery by the current detection means and the voltage detection means, estimates the internal state of the secondary battery from the measured values of the detected current and terminal voltage, and based on the estimated internal state Thus, the problem is solved by detecting a failure of the current detection means and the voltage detection means.

  According to the present invention, the internal state of the secondary battery is estimated from the current and terminal voltage of the secondary battery detected by the current detection unit and the voltage detection unit, and current detection is performed based on the estimated internal state of the secondary battery. By detecting the failure of the means and the voltage detection means, it is possible to appropriately determine which of the current detection means and the voltage detection means is out of order.

FIG. 1 is a diagram illustrating a configuration of a control system for a secondary battery according to the present embodiment. FIG. 2 is a functional block diagram of the electronic control unit 30 according to the present embodiment. FIG. 3 is a diagram showing an equivalent circuit model showing a battery model of the secondary battery. FIG. 4 is a diagram illustrating an example of an open circuit voltage-charge rate characteristic of the secondary battery. FIG. 5 is a flowchart showing the internal state estimation process and sensor failure determination process of the secondary battery in the present embodiment. FIG. 6 is a flowchart showing an internal state estimation process and a sensor failure determination process of a secondary battery in another embodiment.

  FIG. 1 is a diagram illustrating a configuration of a control system for a secondary battery according to the present embodiment. The control system shown in FIG. 1 is applied to the present invention in a system that drives a load such as a motor with a secondary battery or charges a secondary battery with electric power generated by motor regeneration or power generated by an alternator using an engine as a power source. This is an example in which such a secondary battery control device is applied.

  The secondary battery 10 is formed by connecting a plurality of unit batteries in series. Examples of the unit battery constituting the secondary battery 10 include a lithium-based secondary battery such as a lithium ion secondary battery. It is done. An example of the load 20 is a motor.

  The current sensor 40 is a sensor that detects a charging / discharging current flowing through the secondary battery 10, and a signal detected by the current sensor 40 is sent to the electronic control unit 30. The voltage sensor 50 is a sensor that detects the terminal voltage of the secondary battery 10, and a signal detected by the voltage sensor 50 is sent to the electronic control unit 30.

  The electronic control unit 30 is a control unit for controlling the secondary battery 10 and includes a CPU that calculates a program, a microcomputer that includes a ROM and RAM that stores programs and calculation results, an electronic circuit, and the like. . FIG. 2 shows a functional block diagram of the electronic control unit 30.

  As shown in FIG. 2, the electronic control unit 30 includes a current detection unit 301, a voltage detection unit 302, an adaptive digital filter calculation unit 303, a sensor failure detection unit 304, and a charge capacity estimation unit 307. As shown in FIG. 2, the sensor failure detection unit 304 includes a voltage sensor failure detection unit 305 and a current sensor failure detection unit 306.

  The current detection unit 301 acquires a signal from the current sensor 40 at a predetermined period, and detects a charge / discharge current flowing through the secondary battery 10 based on the signal from the current sensor 40, thereby measuring a current measurement value I (t). To get. The current detection unit 301 sends the acquired current measurement value I (t) to the adaptive digital filter calculation unit 303, the sensor failure detection unit 304, and the charge capacity estimation unit 307.

  The voltage detection unit 302 acquires a signal from the voltage sensor 50 at a predetermined period, and acquires a voltage measurement value V (t) by detecting a terminal voltage of the secondary battery 10 based on the signal from the voltage sensor 50. To do. The voltage detection unit 302 sends the acquired voltage measurement value V (t) to the adaptive digital filter calculation unit 303 and the sensor failure detection unit 304.

The adaptive digital filter calculation unit 303 defines a battery model of the secondary battery 10, and the current measurement value I (t) detected by the current detection unit 301 and the voltage measurement value V (t) detected by the voltage detection unit 302. Thus, the internal state of the secondary battery 10 is estimated by collectively estimating the parameters of the battery model of the secondary battery 10 by adaptive digital filter calculation.
Hereinafter, a method for estimating the internal state of the secondary battery 10 by the adaptive digital filter calculation unit 303 will be described.

ここで、モデル入力は電流Ｉ［Ａ］（正値は充電、負値は放電）、モデル出力は端子電圧Ｖ［Ｖ］であり、Ｒ_１〔Ω］は電荷移動抵抗、Ｒ_２［Ω］は純抵抗、Ｃ_１［Ｆ］は電気二重層容量、Ｖ_０［Ｖ］は開路電圧である。また、上記式（１）中、ｓは微分オペレータである。なお、本実施形態に係る電池モデルは、正極、負極を特に分離していないリダクションモデル（１次）であるが、実際の電池の充放電特性を比較的正確に示すことが可能である。このように本実施形態においては、電池モデルの次数を１次にした構成を例として説明する。 First, the “battery model” used in the present embodiment will be described. FIG. 3 is an equivalent circuit model showing a battery model of the secondary battery 10, and the equivalent circuit model shown in FIG. 3 is expressed by the following formula (1).

Here, the model input is current I [A] (positive value is charging, negative value is discharging), model output is terminal voltage V [V], R ₁ [Ω] is charge transfer resistance, R ₂ [Ω] Is a pure resistance, C ₁ [F] is an electric double layer capacitance, and V ₀ [V] is an open circuit voltage. In the above formula (1), s is a differential operator. Note that the battery model according to the present embodiment is a reduction model (primary) in which the positive electrode and the negative electrode are not particularly separated, but it is possible to show the actual charge / discharge characteristics of the battery relatively accurately. As described above, in the present embodiment, a configuration in which the order of the battery model is first will be described as an example.

Here, when R ₁ , R ₂ , and C ₁ are represented by the following formula (2), the above formula (1) is represented by the following formula (3).

Next, a method for estimating battery parameters (K, T ₁ , T ₂ ) using an adaptive digital filter from the battery model represented by the above formula (3) will be described. Assuming that the open circuit voltage V ₀ (t) is obtained by integrating the current I (t) multiplied by the variable parameter h from an initial state, the open circuit voltage V ₀ (t) is expressed by the following equation (4). Can be represented.

When the above formula (4) is substituted into the above formula (3), the following formula (5) is obtained, and when this is arranged, the following formula (6) is obtained.

Furthermore, when both sides of the above equation (6) are multiplied by a stable low-pass filter 1 / G _lp (s) and rearranged, the following equation (7) is obtained.

In the present embodiment, the low-pass filter 1 / G _lp (s) used is represented by the following formula (8), but is not limited to the one represented by the following formula (8). In the following formula (8), τ is a time constant of the filter.

Here, a value obtained by applying a low-pass filter to the measured current value I (t) detected by the current detector 301 and the measured voltage value V (t) detected by the voltage detector 302 is defined by the following equation (9). .

When the above formula (7) is rewritten by the above formula (9) and rearranged for V ₂ (t), the following formula (10) is obtained.

ただし、上記式（１１）中、ｙ＝Ｖ_２(ｔ）、 ω^Ｔ＝［Ｖ_３(ｔ），Ｉ_３(ｔ），Ｉ_２(ｔ），Ｉ_１(ｔ）］、θ＝［−Ｔ_１，Ｋ・Ｔ_２，Ｋ，ｈ］ である。 Then, the above equation (10) is obtained by measuring values (I ₁ (t), I ₂ (t), I ₃ (t), V ₂ (t), V ₃ (t)) and unknown parameters (T ₁ , T ₂ , K, h), and therefore coincides with the following formula (11) which is a standard form of the adaptive digital filter.

In the above formula (11), y = V ₂ (t), ω ^T = [V ₃ (t), I ₃ (t), I ₂ (t), I ₁ (t)], θ = [− T ₁ , K · T ₂ , K, h].

Therefore, by using the signal obtained by filtering the current measurement value I (t) detected by the current detection unit 301 and the voltage measurement value V (t) detected by the voltage detection unit 302 in the adaptive digital filter calculation, An unknown parameter vector θ composed of an internal resistance K representing a state, time constants T ₁ and T ₂ , and a parameter h can be collectively estimated.

In this embodiment, the logical disadvantage of the simple “adaptive digital filter by the least squares method” (because once the estimated value converges, accurate estimation cannot be performed again even if the parameter changes) is improved. "Trace gain method" is used. That is, assuming the above equation (11), an algorithm for estimating the unknown parameter vector θ by the adaptive digital filter is the following equation (12).

また、上記式（１２）において、ｔｒａｃｅ｛Ｑ(ｋ）｝は行列Ｑ(ｋ）のトレース（対角要素の和）を意味し、λ_１、λ_３、γ_Ｕ、γ_Ｌは設計パラメータであり、０＜λ_１＜１、０＜λ_３＜∞とする。λ_３は適応デジタルフィルタの推定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推定速度は速くなるが、その反面ノイズの影響を受けやすくなる。γ_Ｕおよびγ_Ｌはそれぞれ行列Ｑ(ｋ）のトレースの上下限を規定するパラメータであり、０＜γ_Ｌ＜γ_Ｕとなるように設定する。また、Ｐ(０）は十分大きな値を初期値とし、θ＾（０）は非ゼロな十分小さな値を初期値とする。このようにして、適応デジタルフィルタ演算部３０３により、適応デジタルフィルタを用いた電池パラメータ（Ｔ_１，Ｔ_２，Ｋ，ｈ）の推定が行われる。そして、このようにして推定された電池パラメータから、二次電池１０の内部抵抗推定値Ｒ＾（ｔ）、および電気二重層容量推定値Ｃ＾（ｔ）の算出が行われ、これら内部抵抗推定値Ｒ＾（ｔ）、および電気二重層容量推定値Ｃ＾（ｔ）は、電池パラメータ（Ｔ_１，Ｔ_２，Ｋ，ｈ）とともに、センサ故障検出部３０４に送出される。 In the above equation (12), θ ^ (k) means an estimated value of the battery parameter θ (k) at time k. Further, “^” attached to the right shoulder in θ ^ (k) indicates that the value is an estimated value. In the above equation (12), the estimated value “^” is shown immediately above “θ” of θ (k), but as shown in the following equation (13), this Synonymous with (k). _{Hereinafter, R ^ (t), C} ^ (t), V 0 ^ (t), V ^ (t), I ^ (t), SOC ^ (t), is the same in Cap ^ (t).

In the above equation (12), trace {Q (k)} means a trace (sum of diagonal elements) of the matrix Q (k), and λ ₁ , λ ₃ , γ _U and γ _L are design parameters. Yes, 0 <λ ₁ <1, 0 <λ ₃ <∞. lambda ₃ is a constant (adjustment gain) for setting the estimated speed of the adaptive digital filter, but the estimated speed is faster by increasing the value becomes susceptible to the contrary noise. γ _U and γ _L are parameters that define the upper and lower limits of the trace of the matrix Q (k), and are set such that 0 <γ _L <γ _U. Also, P (0) has a sufficiently large value as an initial value, and θ ^ (0) has a non-zero and sufficiently small value as an initial value. In this way, the adaptive digital filter calculation unit 303 estimates the battery parameters (T ₁ , T ₂ , K, h) using the adaptive digital filter. Then, the estimated internal resistance value R ^ (t) and the estimated electric double layer capacity C ^ (t) of the secondary battery 10 are calculated from the battery parameters estimated in this way, and these estimated internal resistance values are calculated. The value R ^ (t) and the electric double layer capacity estimated value C ^ (t) are sent to the sensor failure detection unit 304 together with the battery parameters (T ₁ , T ₂ , K, h).

Furthermore, the adaptive digital filter calculation unit 303 uses the battery parameters (T ₁ , T ₂ , K, h) calculated according to the above-described method and the current measurement value I (t) detected by the current detection unit 301, for example, The terminal voltage estimated value V ^ (t) is calculated from the above equation (6). Similarly, the adaptive digital filter calculation unit 303 similarly uses the calculated battery parameters (T ₁ , T ₂ , K, h) and the voltage measurement value V (t) detected by the voltage detection unit 302 to, for example, The current estimated value I ^ (t) is calculated from the equation (6). The calculated voltage estimated value V ^ (t) and current estimated value I ^ (t) are also the internal resistance estimated value R ^ (t), the electric double layer capacity estimated value C ^ (t), and the battery parameter ( Along with T ₁ , T ₂ , K, h), it is sent to the sensor failure detection unit 304.

In addition, the adaptive digital filter calculation unit 303 calculates the open circuit voltage V ₀ of the secondary battery 10 from the estimated battery parameters as follows. First and rearranging the above equation (3) open-circuit voltage _{V 0,} the following equation (14).

Since the change in the open circuit voltage V ₀ (t) is relatively gentle, the both sides of the above equation (14) are multiplied by a stable low-pass filter 1 / G _lp (s) and multiplied by 1 / G _lp (s). The obtained value is estimated as the open circuit voltage estimated value V ₀ ^ (t) by the following equation (15).

When the above formula (9) is substituted into the above formula (15), the following formula (16) is obtained.

Therefore, the battery parameter estimated values (T ₁ , T ₂ , K) estimated using the adaptive digital filter and the outputs (I ₁ (t), I ₂ (t), V ₁ By substituting (t) and V ₂ (t)), it is possible to estimate the open circuit voltage, thereby calculating the open circuit voltage estimated value V ₀ ^ (t). The calculated open circuit voltage estimated value V ₀ ^ (t) is sent to the sensor failure detection unit 304 and the charge capacity estimation unit 307. Moreover, the open circuit voltage estimated value V ₀ ^ (t) is used for various calculations for controlling the secondary battery 10 such as estimation of chargeable / dischargeable capacity of the secondary battery 10 and estimation of input / output possible power.

  Further, the adaptive digital filter calculation unit 303 acquires failure determination results of the current sensor 40 and the voltage sensor 50 from a sensor failure detection unit 304 described later. When the sensor failure detection unit 304 acquires a determination result indicating that the current sensor 40 has failed, the adaptive digital filter calculation unit 303 measures the voltage measurement value V (t) detected by the voltage detection unit 301. The adaptive digital filter operation is performed using only Similarly, when the adaptive digital filter calculation unit 303 obtains a determination result indicating that the voltage sensor 50 has failed by the sensor failure detection unit 304, the current measurement value I (t detected by the current detection unit 301 is obtained. ) Is used to perform an adaptive digital filter operation.

The sensor failure detection unit 304 is calculated by the current measurement value I (t) detected by the current detection unit 301, the voltage measurement value V (t) detected by the voltage detection unit 302, and the adaptive digital filter calculation unit 303. current estimated value I ^ was (t), voltage estimation value V ^ (t), open circuit voltage estimated value _V 0 ^ (t), the internal resistance estimated value R ^ (t), the electric double layer capacity estimated value C ^ (t ) And the battery parameters (T ₁ , T ₂ , K, h), it is detected whether at least one of the current sensor 40 and the voltage sensor 50 has failed. If it is determined that at least one of the current sensor 40 and the voltage sensor 50 has failed, the voltage sensor failure detection unit 305 causes either of the current sensor 40 and the voltage sensor 50 to fail. A determination is made as to whether or not Then, the determination result is sent to the adaptive digital filter calculation unit 303 and the charge capacity estimation unit 307. The failure determination method by the sensor failure detection unit 304 and the voltage sensor failure detection unit 305 will be described later.

The charge capacity estimation unit 307 uses the open circuit voltage estimated value V ₀ ^ (t) calculated by the adaptive digital filter calculation unit 303 based on the open circuit voltage-charge rate characteristics of the secondary battery 10 acquired in advance. The charging rate of the secondary battery 10 is estimated, and thereby the charging rate estimated value SOC ^ (t) is calculated. Then, the charge capacity estimation unit 307 calculates the charge capacity estimation value Cap ^ (t) of the secondary battery 10 from the charge rate estimation value SOC ^ (t) and the battery capacity of the secondary battery 10. Here, an example of the open circuit voltage-charge rate characteristic of the secondary battery 10 is shown in FIG. In the present embodiment, the open circuit voltage-charge rate characteristic of the secondary battery 10 is stored in advance in a RAM provided in the electronic control unit 30, and the open circuit voltage and the charge rate of the secondary battery 10 are previously determined through experiments or the like. It can obtain by calculating | requiring the relationship.

  In addition, the charge capacity estimation unit 307 acquires failure determination results of the current sensor 40 and the voltage sensor 50 from the sensor failure detection unit 304. When the determination result indicating that the voltage sensor 50 has failed is acquired by the sensor failure detection unit 304, the charge capacity estimation unit 307 measures the current detected by the current detection unit 301 instead of the above method. By accumulating the value I (t), the charge capacity of the secondary battery 10 is estimated, and the charge capacity estimated value Cap ^ (t) of the secondary battery 10 is calculated. On the other hand, when the sensor failure detection unit 304 acquires a determination result indicating that the current sensor 40 has failed, the charge capacity estimation unit 307 measures the voltage detected by the voltage detection unit 302 instead of the above method. By using only the value V (t), the current estimated value I ^ (t) calculated by the adaptive digital filter calculation unit 303 is obtained, and the current estimated value I ^ (t) is integrated to obtain the secondary battery 10. And the estimated charge capacity Cap ^ (t) of the secondary battery 10 is calculated.

  Next, the internal state estimation process and sensor failure determination process of the secondary battery 10 in the present embodiment will be described with reference to the flowchart shown in FIG. Note that the processing shown in FIG. 5 is performed at regular intervals (in this embodiment, every 100 msec). In the following description, I (k) is a current value (current measurement value) of the current execution cycle, I (k−1) is a current value (previous measurement value) of the previous execution cycle, The same applies to values other than current. Note that the processing described below is performed by the electronic control unit 30.

  First, in step S1, the current measurement value I (k) and the voltage measurement value V (k) are acquired by the current detection unit 301 and the voltage detection unit 302. The measured current value I (k) is sent to the adaptive digital filter calculation unit 303, the sensor failure detection unit 304 and the charge capacity estimation unit 307, and the measured voltage value V (k) is sent to the adaptive digital filter calculation unit 303 and the sensor failure detection unit 304. Each is sent out.

In step S2, the adaptive digital filter calculation unit 303 performs battery parameter calculation by adaptive digital filter calculation according to the above-described method based on the current measurement value I (k) and voltage measurement value V (k) acquired in step S1. (T ₁ , T ₂ , K, h), internal resistance estimated value R ^ (k), electric double layer capacity estimated value C ^ (k), current estimated value I ^ (k), voltage estimated value V ^ (k ), And an open circuit voltage estimated value V ₀ ^ (k) are calculated, and these are sent to the sunsa failure detection unit 304. The calculated open circuit voltage estimated value V ₀ ^ (k) is also sent to the charge capacity estimating unit 307.

  In step S <b> 3, the sensor failure detection unit 304 determines whether at least one of the current sensor 40 and the voltage sensor 50 has failed. The sensor failure detection unit 304 determines whether or not at least one of the current sensor 40 and the voltage sensor 50 has failed, for example, based on the following criteria.

[a1] That is, first, the sensor failure detection unit 304 determines that at least one of the battery parameters (T ₁ , T ₂ , K, h) calculated by the adaptive digital filter calculation unit 303 is once. It is determined that at least one of the current sensor 40 and the voltage sensor 50 is out of order when it changes by a predetermined value or more compared to the previous execution cycle (k−1). Since these battery parameters (T ₁ , T ₂ , K, h) usually change gradually and do not change greatly in a short time, the battery parameters (T ₁ , T ₂ , K) , H), when at least one parameter changes by a predetermined value or more, it can be determined that at least one of the current sensor 40 and the voltage sensor 50 has failed. Therefore, in this embodiment, in such a case, it is determined that one of the sensors has failed.
In this case, whether at least one of the battery parameters (T ₁ , T ₂ , K, h) has changed by a predetermined value or more compared to the previous execution cycle (k−1). For example, when the battery parameters are stored for a predetermined time and the change amount of at least one parameter among the change amounts of these battery parameters during the predetermined time is equal to or greater than a predetermined value, the current sensor 40 The voltage sensor 50 may be configured to determine that at least one of the sensors is out of order.

[a2] Secondly, the sensor failure detection unit 304 includes an open circuit voltage estimated value V ₀ (k), an internal resistance estimated value R (k) calculated by the adaptive digital filter calculation unit 303, and an electric double layer capacitance. At least one of the current sensor 40 and the voltage sensor 50 when at least one of the estimated values C ^ (k) changes by a predetermined value or more compared to the previous execution cycle (k-1). Is determined to be malfunctioning. Since the open circuit voltage V ₀ , the internal resistance R, and the electric double layer capacity C of the secondary battery 10 normally change gradually and do not change significantly in a short time, the open circuit voltage estimated value V _When at least one of ₀ ^ (k), internal resistance estimated value R ^ (k), and electric double layer capacity estimated value C ^ (k) changes by a predetermined value or more, the current sensor 40 and the voltage sensor 50 It can be determined that at least one of the sensors is out of order. Therefore, in this embodiment, in such a case, it is determined that one of the sensors has failed.
Even in this case, at least one of the open circuit voltage estimated value V ₀ ^ (k), the internal resistance estimated value R ^ (k), and the electric double layer capacity estimated value C ^ (k) is Instead of determining whether the value has changed by a predetermined value or more compared to the execution cycle (k-1), for example, each of these estimated values is stored for a predetermined time, and the amount of change of each estimated value in the predetermined time The configuration may be such that when at least one estimated change amount is equal to or greater than a predetermined value, it is determined that at least one of the current sensor 40 and the voltage sensor 50 is out of order.

  [a3] Third, the sensor failure detection unit 304 includes the current measurement value I (k) detected by the current detection unit 301 and the current estimation value I ^ (k) calculated by the adaptive digital filter calculation unit 303. When there is a difference of a predetermined value or more between these, it is determined that at least one of the current sensor 40 and the voltage sensor 50 has failed. The current measurement value I (k) and the current estimation value I ^ (k) usually do not greatly deviate from each other. Therefore, when these differences are equal to or greater than a predetermined value, the current sensor 40 and the voltage sensor 50 It can be determined that at least one of the sensors is out of order. Therefore, in this embodiment, in such a case, it is determined that one of the sensors has failed.

  Based on the above criteria, the sensor failure detection unit 304 determines whether at least one of the current sensor 40 and the voltage sensor 50 has failed.

  If it is determined that neither the current sensor 40 nor the voltage sensor 50 has failed as a result of the determination by the sensor failure detection unit 304, both the current sensor 40 and the voltage sensor 50 are normal in step S4. After the determination is made and the determination result is sent to the adaptive digital filter calculation unit 303 and the charge capacity estimation unit 307, the process proceeds to step S8. On the other hand, as a result of the determination by the sensor failure detection unit 304, when it is determined that at least one of the current sensor 40 and the voltage sensor 50 has failed, the process proceeds to step S5.

  In step S5, the voltage sensor failure detection unit 305 determines whether or not the voltage sensor 50 has failed. Note that the voltage sensor failure detection unit 305 determines whether or not the voltage sensor 50 has failed, for example, based on the following criteria.

  [b1] That is, first, the voltage sensor failure detection unit 305 causes the voltage sensor 50 to fail when the internal resistance estimated value R ^ (k) calculated by the adaptive digital filter calculation unit 303 converges to zero. Judge that The secondary battery 10 normally has a predetermined resistance value, and therefore the internal resistance R of the secondary battery 10 does not become zero. On the other hand, when the voltage sensor 50 is faulty, the internal resistance estimated value R ^ (k) tends to converge to zero. In this embodiment, in this case, the voltage sensor 50 Judge that it is broken. The determination as to whether or not the internal resistance estimated value R ^ (k) has converged to zero is made, for example, by storing the internal resistance estimated value R ^ (k) over a predetermined time and the internal resistance estimated value at the predetermined time. This can be determined based on the transition of R ^ (k).

  [b2] Secondly, the voltage sensor failure detection unit 305 detects the voltage measurement value V (k) detected by the voltage detection unit 302 and the estimated voltage value V ^ (k) calculated by the adaptive digital filter calculation unit 303. And if there is a difference of a predetermined value or more between them, it is determined that the voltage sensor 50 has failed. Normally, the voltage measurement value V (k) and the voltage estimation value V ^ (k) do not greatly deviate from each other, but when the voltage sensor 50 is broken, these differences tend to deviate. . Therefore, in this embodiment, it is determined that the voltage sensor 50 has failed in such a case.

[b3] Third, the voltage sensor failure detection unit 305 determines that the voltage sensor 50 has failed when the parameter h calculated by the adaptive digital filter calculation unit 303 converges to zero. As shown in the equation (4), the open circuit voltage V ₀ can be considered as an integral of a current flowing through the secondary battery multiplied by a variable parameter h, which is integrated from a certain initial state. , Never zero. On the other hand, when the voltage sensor 50 is faulty, the parameter h tends to converge to zero. Therefore, in this embodiment, it is determined that the voltage sensor 50 is faulty in such a case. . The determination as to whether or not the parameter h has converged to zero can be made based on, for example, the parameter h stored for a predetermined time and the transition of the parameter h over the predetermined time.

[b4] Fourth, the voltage sensor failure detection unit 305 measures the current detected by the current sensor 40 among the battery parameters (T ₁ , T ₂ , K, h) calculated by the adaptive digital filter calculation unit 303. When the parameter corresponding to the value I (k) converges to zero, it is determined that the voltage sensor 50 has failed. Here, in the adaptive digital filter calculation performed by the adaptive digital filter calculation unit 303, between the current measurement value I (k) detected by the current sensor 40 and the voltage measurement value V (k) detected by the voltage sensor 50. The battery parameters (T ₁ , T ₂ , K, h) are calculated by weighting them on the assumption that there is a certain correlation. However, on the other hand, when a failure occurs in the voltage sensor 50, it is not possible to acquire an accurate voltage measurement value V (k), and as a result, the current measurement value I (k) and the voltage measurement value V ( k) is lost, and as a result, among the battery parameters (T ₁ , T ₂ , K, h), the parameter corresponding to the current measurement value I (k) detected by the current sensor 40 is zero. Tend to converge. Therefore, in this embodiment, it is determined that the voltage sensor 50 has failed in such a case. Note that the determination of whether or not the parameter corresponding to the current measurement value I (k) has converged to zero is, for example, storing the parameter corresponding to the current measurement value I (k) for a predetermined time, Judgment can be made based on the transition of parameters. Among the battery parameters (T ₁ , T ₂ , K, h), parameters corresponding to the current measurement value I (k) detected by the current sensor 40 include parameters T ₂ , K, h ( (See the above formula (10)).

  Based on the above criteria, the voltage sensor failure detection unit 305 determines whether or not the voltage sensor 50 has failed.

  If it is determined as a result of determination by the voltage sensor failure detection unit 305 that the voltage sensor 50 has failed, it is determined in step S6 that the voltage sensor 50 has failed, and the determination result. Is sent to the adaptive digital filter calculation unit 303 and the charge capacity estimation unit 307, and then the process proceeds to step S8. On the other hand, as a result of determination by the voltage sensor failure detection unit 305, when it is determined that the voltage sensor 50 has not failed, it is determined in step S7 that the current sensor 40 has failed, and the determination result Is sent to the adaptive digital filter calculation unit 303 and the charge capacity estimation unit 307, and then the process proceeds to step S8.

In step S <b> 8, the charge capacity estimation unit 307 calculates the charge capacity estimation value Cap ^ (k) of the secondary battery 10. When the charge capacity estimation unit 307 has acquired a determination result indicating that both the current sensor 40 and the voltage sensor 50 are normal, the open circuit voltage estimation value V ₀ ^ calculated by the adaptive digital filter calculation unit 303 (K) is used to calculate the estimated charging rate SOC ^ (k), and based on this, the estimated charging capacity Cap ^ (k) of the secondary battery 10 is calculated. In addition, when the determination result that the voltage sensor 50 has failed is acquired, the charging capacity estimation unit 307 integrates the current measurement value I (k) detected by the current detection unit 301. Then, the estimated charge capacity Cap ^ (k) of the secondary battery 10 is calculated. Furthermore, when the determination result that the current sensor 40 has failed is acquired, the charge capacity estimation unit 307 is adapted using only the voltage measurement value V (k) detected by the voltage detection unit 302. The estimated current value I ^ (k) calculated by the digital filter calculation unit 303 is acquired, and the estimated current value I ^ (k) of the secondary battery 10 is obtained by integrating the estimated current value I ^ (k). calculate.

  In the present embodiment, the internal state estimation process and sensor failure determination process of the secondary battery 10 are performed as described above.

  According to the present embodiment, by the adaptive digital filter calculation using the battery model, the parameters of the battery model of the secondary battery 10 are collectively estimated, the internal state of the secondary battery 10 is estimated, and based on the result, Since the failure of the current sensor 40 and the voltage sensor 50 is detected, it is possible to appropriately determine which of the current sensor 40 and the voltage sensor 50 has failed. In particular, according to the present embodiment, other information such as measurement values and temperature information other than the current measurement value I (k) detected by the current sensor 40 and the voltage measurement value V (k) detected by the voltage sensor 50. It is possible to appropriately determine which of the current sensor 40 and the voltage sensor 50 is malfunctioning without using.

  In addition, according to the present embodiment, when either one of the current sensor 40 and the voltage sensor 50 is out of order, the charge capacity estimation value Cap ^ (k) is calculated by the charge capacity estimation unit 307. Since the change is made according to the type of the sensor in which the failure is detected, even if a failure is detected in either the current sensor 40 or the voltage sensor 50, the charge capacity estimation value Cap ^ (k) Can be continued. As a result, the control accuracy of the secondary battery 10 (for example, the estimation accuracy of the chargeable / dischargeable capacity of the secondary battery 10 and the estimation accuracy of the input / output possible power) can be improved.

  In the embodiment described above, the current sensor 40 is the current detection means of the present invention, the voltage sensor 50 is the voltage detection means of the present invention, and the adaptive digital filter calculation unit 303 is the internal state estimation means and voltage estimation means of the present invention. Furthermore, the sensor failure detection unit 304, the voltage sensor failure detection unit 305, and the current sensor failure detection unit 306 correspond to the failure detection means of the present invention.

  As mentioned above, although embodiment of this invention was described, these embodiment was described in order to make an understanding of this invention easy, and was not described in order to limit this invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  For example, in the above-described embodiment, as shown in FIG. 5, in step S <b> 5, the voltage sensor failure detection unit 305 determines whether or not the voltage sensor 50 has failed, and based on this, the current sensor 40 and the voltage sensor 50. As shown in FIG. 6, the current sensor failure detection unit 306 determines whether or not the current sensor 40 has failed, and based on this, as shown in FIG. It may be configured to determine which of the sensors 50 has failed (step S5 ′ in FIG. 6). FIG. 6 is a flowchart showing the internal state estimation process and sensor failure determination process of the secondary battery in another embodiment, except that step S5 ′ is executed instead of step S5 in the flowchart shown in FIG. It has become the same.

  In the flowchart shown in FIG. 6, when it is determined that at least one of the current sensor 40 and the voltage sensor 50 has failed as a result of the determination by the sensor failure detection unit 304 in step S4, step S5 is performed. Then, the current sensor failure detection unit 306 determines whether or not the current sensor 40 has failed. Note that the current sensor failure detection unit 306 determines whether or not the current sensor 40 has failed, for example, based on the following criteria.

That is, the current sensor failure detection unit 306 includes the measured voltage value V (k) detected by the voltage sensor 50 among the battery parameters (T ₁ , T ₂ , K, h) calculated by the adaptive digital filter calculation unit 303. When the parameter corresponding to 1 converges to a predetermined value, it is determined that the current sensor 40 has failed. As described above, in the adaptive digital filter calculation performed by the adaptive digital filter calculation unit 303, the current measurement value I (k) detected by the current sensor 40 and the voltage measurement value V (k) detected by the voltage sensor 50. The battery parameters (T ₁ , T ₂ , K, h) are calculated by weighting them on the assumption that there is a certain correlation between the _two . However, on the other hand, when a failure occurs in the current sensor 40, it is impossible to acquire an accurate current measurement value I (k), and as a result, the current measurement value I (k) and the voltage measurement value V ( k) is lost, and as a result, among the battery parameters (T ₁ , T ₂ , K, h), a parameter corresponding to the voltage measurement value V (k) detected by the voltage sensor 50 is predetermined. It tends to converge to a value. Therefore, in this embodiment, in such a case, it is determined that the current sensor 50 has failed. Note that the determination of whether or not the parameter corresponding to the voltage measurement value V (k) has converged to a predetermined value is performed by, for example, storing the parameter corresponding to the voltage measurement value V (k) for a predetermined time. It can be determined based on the transition of parameters in Among the battery parameters (T ₁ , T ₂ , K, h), a parameter corresponding to the voltage measurement value V (k) detected by the voltage sensor 50 includes the parameter T ₁ (the above formula (10 )reference).

  If the current sensor failure detection unit 306 determines that the current sensor 40 has failed, it is determined in step S7 that the current sensor 40 has failed, and the determination result. Is sent to the adaptive digital filter calculation unit 303 and the charge capacity estimation unit 307, and then the process proceeds to step S8. On the other hand, as a result of determination by the current sensor failure detection unit 306, when it is determined that the current sensor 40 has not failed, it is determined in step S6 that the voltage sensor 50 has failed, and the determination result Is sent to the adaptive digital filter calculation unit 303 and the charge capacity estimation unit 307, and then the process proceeds to step S8.

DESCRIPTION OF SYMBOLS 10 ... Secondary battery 20 ... Load 30 ... Electronic control unit 301 ... Current detection part 302 ... Voltage detection part 303 ... Adaptive digital filter calculating part 304 ... Sensor failure detection part 305 ... Voltage sensor failure detection part 306 ... Current sensor failure detection part 307 ... Charge capacity estimation unit 40 ... Current sensor 50 ... Voltage sensor

Claims (10)

Current detection means for detecting the current of the secondary battery;
Voltage detecting means for detecting a terminal voltage of the secondary battery;
An internal state estimating means for estimating an internal state of the secondary battery from measured values of the current and terminal voltage detected by the current detecting means and the voltage detecting means;
A failure detection means for detecting a failure of the current detection means and the voltage detection means based on the internal state of the secondary battery estimated by the internal state estimation means;
A control apparatus for a secondary battery comprising:   The internal state estimation means defines a battery model of the secondary battery, and performs an adaptive digital filter operation using the battery model from measured values of current and terminal voltage detected by the current detection means and voltage detection means. The secondary battery control device according to claim 1, wherein the internal state of the secondary battery is estimated by performing batch estimation of parameters of the battery model. The internal state estimating means collectively estimates parameters including an internal resistance of the secondary battery, an electric double layer capacity of the secondary battery, and a parameter h satisfying the following formula (I) by an adaptive digital filter calculation. The secondary battery control device according to claim 2, wherein an internal state of the secondary battery is estimated.

In the above formula (I), V ₀ is an open circuit voltage, I is a measured value of current, and s is a differential operator.   The failure detection means determines that the voltage detection means has failed when the estimated value of the internal resistance of the secondary battery estimated by the internal state estimation means converges to zero. Item 4. The secondary battery control device according to Item 3. Voltage estimation means for estimating the terminal voltage of the secondary battery from the internal state of the secondary battery estimated by the internal state estimation means and the measured value of the current detected by the current detection means;
The failure detection means compares the measured value of the terminal voltage detected by the voltage detection means with the estimated value of the terminal voltage estimated by the voltage estimation means, and compares the measured value of the terminal voltage and the terminal voltage. 5. The secondary battery control device according to claim 1, wherein when the difference from the estimated value is equal to or greater than a predetermined value, it is determined that the voltage detection unit is out of order.   The said failure detection means determines with the said voltage detection means having failed, when the parameter h estimated by the said internal state estimation means converges to zero. The control apparatus of the secondary battery as described.   The failure detection means, when the parameter corresponding to the measured value of the current detected by the current detection means among the parameters collectively estimated by the adaptive digital filter calculation by the internal state estimation means converges to zero, The secondary battery control device according to claim 2, wherein the voltage detection unit is determined to be out of order.   The failure detection means, when the parameter corresponding to the measured value of the terminal voltage detected by the voltage detection means among the parameters collectively estimated by the adaptive digital filter calculation by the internal state estimation means converges to a predetermined value The control device for a secondary battery according to claim 2, wherein the current detection unit is determined to be faulty. Charging capacity estimating means for estimating the charging capacity of the secondary battery,
The charge capacity estimating means integrates the measured value of the current detected by the current detecting means when the voltage detecting means is determined to be out of order by the failure detecting means. Estimate the battery charge capacity,
The charge capacity estimating means determines that the current of the secondary battery from the measured value of the terminal voltage detected by the voltage detecting means when the failure detecting means determines that the current detecting means is out of order. The secondary battery control device according to claim 1, wherein the charge capacity of the secondary battery is estimated by estimating the value and integrating the estimated current value. A method for detecting a failure of a current detection means for detecting a current of a secondary battery and a voltage detection means for detecting a terminal voltage of the secondary battery,
The internal state of the secondary battery is estimated from the measured values of the current and the terminal voltage detected by the current detection unit and the voltage detection unit, and the failure of the current detection unit and the voltage detection unit is based on the estimated internal state. Detecting a fault.

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