JP2013085379A - Battery control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery control device that appropriately detects a current reversible capacity value of a secondary battery.SOLUTION: The battery control device provided calculates an AC resistance value and an imaginary value of the AC resistance value under the application of an AC voltage to a secondary battery, calculates a reversible capacity value based on the AC resistance value and a reversible capacity value based on the imaginary value on the basis of the AC resistance value and the imaginary value of the AC resistance value, and calculates a current reversible capacity value of the secondary battery on the basis of the reversible capacity value based on the AC resistance value and the reversible capacity value based on the imaginary value both thus calculated.

Description

  The present invention relates to a battery control device.

  Susceptance and conductance are calculated by applying an AC voltage of a predetermined frequency to a secondary battery such as a nickel metal hydride battery, lead storage battery, or lithium ion battery, and calculating the integral value of the response current when the AC voltage is applied. And the technique of detecting the dischargeable capacity | capacitance of a secondary battery based on the calculated susceptance and conductance is known (for example, refer patent document 1).

JP 2008-107168 A

  The prior art integrates the response current when an alternating voltage of a predetermined frequency is applied, and calculates the dischargeable capacity of the secondary battery based on the obtained integrated value. On the other hand, since the response current obtained when an AC voltage is applied is generally affected by the resistance component of the secondary battery, the resistance deterioration proceeds inside the secondary battery. When the resistance of the secondary battery increases, the response current has a property that its value decreases due to the influence of the resistance component. Therefore, as in the above-described prior art, in the technique of calculating the integral value of the response current and calculating the dischargeable capacity based on the calculated integral value, when the resistance deterioration proceeds and the response current value becomes small, There is a problem that the calculation accuracy of the obtained integral value is lowered, and as a result, the calculation accuracy of the dischargeable capacity is lowered.

  The problem to be solved by the present invention is to provide a battery control device capable of appropriately detecting the current reversible capacity value of a secondary battery.

  The present invention calculates an imaginary value of an AC resistance value and an AC resistance value when an AC voltage is applied to a secondary battery, and is reversible based on an AC resistance value based on the imaginary value of the AC resistance value and the AC resistance value. Calculate the reversible capacity value based on the capacity value and the imaginary value, and calculate the current reversible capacity value of the secondary battery based on the reversible capacity value based on the calculated AC resistance value and the reversible capacity value based on the imaginary value. Thus, the above problem is solved.

  According to the present invention, it is possible to appropriately calculate the reversible capacity value of the secondary battery without being affected by the resistance deterioration inside the secondary battery due to the increase in the resistance of the secondary battery.

FIG. 1 is a configuration diagram showing a battery control system according to the present embodiment. FIG. 2 is a graph showing an example of an alternating current applied by the alternating current power supply 30 and a response current with respect to the alternating current. FIG. 3 is a diagram showing an equivalent circuit model of the secondary battery 40 according to the present embodiment. FIG. 4 is a diagram showing a simulation result showing a change in AC resistance | Z | when the electric double layer capacitance C1 is changed. FIG. 5 is a diagram showing a simulation result showing a change in reactance −Z ″ when the electric double layer capacitance C1 is changed. FIG. 6 is a flowchart showing a method for calculating the current reversible capacity value Q _REV of the secondary battery 40 in the present embodiment. FIG. 7A is a diagram showing the relationship between the change in the reversible capacity value Q _REV and the AC resistance | Z | when the secondary battery 40 is repeatedly charged and discharged, and FIG. definitive when the performed repeatedly charged and discharged for the next cell 40 is a graph showing the variation of reversible capacity value Q _REV, the relationship between the reactance -Z ''. Figure 8 is a diagram for explaining a method of setting the frequency f _c of the AC voltage in the present embodiment. Figure 9 is a diagram for explaining another method of setting the frequency f _c of the AC voltage in the present embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a configuration diagram showing a battery control system according to the present embodiment. As shown in FIG. 1, the battery control system according to the present embodiment is a system for controlling a secondary battery 40, and includes a battery controller 10, a charge / discharge device 20, and an AC power supply 30.

  The secondary battery 40 is not particularly limited, and includes various secondary batteries such as a lithium ion secondary battery, a nickel cadmium battery, a nickel metal hydride battery, and a lead storage battery. In addition, in this embodiment, although the case where the secondary battery 40 is a lithium ion secondary battery is illustrated and demonstrated, it is not specifically limited to a lithium ion secondary battery.

  The charging / discharging device 20 is a device for charging / discharging the secondary battery 40, and charges and discharges the secondary battery 40 based on a command from the battery controller 10.

The AC power supply 30 is a device for applying an AC voltage to the secondary battery 40, and applies an AC voltage having a predetermined frequency f _{C to} the secondary battery 40 based on a command from the battery controller 10. The AC power supply 30 detects the AC voltage applied to the secondary battery 40 and the response current to the AC voltage, and transmits the detected AC voltage and response current to the battery controller 10. FIG. 2 shows an example of an alternating current applied by the alternating current power supply 30 and a response current for the alternating current.

The battery controller 10 is a device for controlling the secondary battery 40 by controlling the charging / discharging device 20 and the AC power supply 30. In the present embodiment, the battery controller 10 determines the current reversible capacity value Q of the secondary battery 40 based on the AC voltage applied to the secondary battery 40 by the AC power supply 30 and the response current to the AC current. _REV is calculated. Hereinafter, a method for calculating the current reversible capacity value Q _REV of the secondary battery 40 by the battery controller 10 will be described in detail.

First, the battery controller 10 determines the AC resistance | Z of the secondary battery 40 according to the following formula (1) based on the AC voltage applied to the secondary battery 40 by the AC power supply 30 and the response current to the AC current. | Is calculated.
| Z | = V ₀ / I ₀ (1)
In the above formula (1), V ₀ is the amplitude of the AC voltage applied to the secondary battery 40 as shown in FIG. 2, and I ₀ is the amplitude of the response current with respect to the AC current. is there.

Next, the battery controller 10 uses the AC voltage applied to the secondary battery 40 by the AC power supply 30 and further the following formulas (2) to (2) based on the AC resistance | Z | calculated according to the above formula (1). According to (4), the phase difference θ between the AC voltage and the response current, the conductance Z ′ of the AC resistance | Z |, and the reactance −Z ″ of the AC resistance | Z |
θ = 2π · f _c · t (2)
Z ′ = | Z | cos θ (3)
−Z ″ = | Z | sin θ (4)
In the formula (2), f _c is the frequency of the AC voltage applied to the secondary battery 40, t is (in FIG. 2, V ₀₎ peak of the AC voltage from the response current peak (FIG. 2 The time until I ₀ ) is obtained.

Here, FIGS. 4 and 5 show simulation results showing changes in the AC resistance | Z | and the reactance -Z ″ when AC voltages having different frequencies are applied to the equivalent circuit shown in FIG. The equivalent circuit shown in FIG. 3 is an equivalent circuit model showing the secondary battery 40. In FIG. 3, R1 is a resistance derived from the electrolyte between the positive and negative electrodes (for example, Li ions move between the positive and negative electrodes). R2 is a reaction resistance (mainly positive and negative reaction resistance), and C1 is an electric double layer capacity (mainly an electric double layer capacity on the surface of the positive electrode active material and the surface of the negative electrode active material). in and, Z _w is the resistance derived from the electrolytic solution in the positive and negative in-electrode (e.g., resistance when Li ions move in the electrode). 4 and 5 show simulation results showing changes in AC resistance | Z | and reactance −Z ″ when the electric double layer capacitance C1 is changed in the equivalent circuit shown in FIG. Yes.

FIG. 4 shows a simulation result of the AC resistance | Z | when the electric double layer capacitance C1 is changed. As shown in FIG. 4, when the frequency of the AC voltage is 1 Hz, the electric double When the multilayer capacitance C1 decreases, the AC resistance | Z | starts to increase at the electric double layer capacitance C1 = 1.0 × 10 ⁻¹ F, and the AC double layer capacitance C1 = 1.0 × 10 ⁻⁴ F When the resistance | Z | increases and the electric double layer capacitance C1 = 1.0 × 10 ⁻⁴ F or less, the AC resistance | Z | does not change. Such a tendency is the same even when the frequency of the AC voltage is 10 kHz, 100 kHz, 1000 kHz, or 10,000 kHz. However, as the frequency of the AC voltage increases, the point at which the AC resistance | Z | starts to rise tends to be on the lower capacity side.

FIG. 5 shows a simulation result of reactance −Z ″ when the electric double layer capacitance C1 is changed. As shown in FIG. 5, when the frequency of the AC voltage is 1 Hz, As the electric double layer capacitance C1 decreases, the reactance -Z ″ starts to increase from the electric double layer capacitance C1 = 1.0 × 10 ⁰ F, and the electric double layer capacitance C1 = 1.0 × 10 ⁻² F The reactance −Z ″ becomes the maximum value, and then the electric double layer capacitance C1 = 1.0 × 10 ⁻⁶ F, and the reactance −Z ″ becomes the base value. Such a tendency is the same even when the frequency of the AC voltage is 10 kHz, 100 kHz, 1000 kHz, or 10,000 kHz. However, as the frequency of the AC voltage increases, the maximum value of the reactance −Z ″ tends to be lower.

Here, the electric double layer capacity C1 is equal to the reversible capacity value Q _REV of the secondary battery 40, and is mainly the electric double layer capacity on the surface of the positive electrode active material and the surface of the negative electrode active material constituting the secondary battery 40. When there is a sufficient amount of electrolyte near the surfaces of the active material and the negative electrode active material, and there are sufficient Li ions near the surfaces of the positive electrode active material and the negative electrode active material, the electric double layer capacity C1 Tends to be relatively high. That is, in this case, the current reversible capacity value _QREV of the secondary battery 40 tends to be relatively high.

On the other hand, when the electrolyte solution is depleted near the surfaces of the positive electrode active material and the negative electrode active material, and the amount of Li ions present near the surfaces of the positive electrode active material and the negative electrode active material is not sufficient, The electric double layer capacity C1 tends to be relatively low. That is, in this case, the current reversible capacity value _QREV of the secondary battery 40 tends to be relatively low.

Therefore, in this embodiment, the battery controller 10 stores in advance the relationship between such an AC resistance | Z | and reactance −Z ″ and the reversible capacity value Q _REV (electric double layer capacity C1). AC resistance | Z |, and the reactance -Z '', based on the relationship between the reversible capacity value Q _{REV (electric} double layer capacitor C1), and calculates the current reversible capacity value Q _REV of the rechargeable battery 40 .

Hereinafter, a specific method for calculating the reversible capacity value Q _REV of the secondary battery 40 using the relationship between the AC resistance | Z | and the reactance −Z ″ and the electric double layer capacity C1 by the battery controller 10 will be described. This will be described with reference to the flowchart shown in FIG.

First, in step S <b> 1, the battery controller 10 performs a process of sending a signal for applying an AC voltage to the secondary battery 40 to the AC power supply 30. Then, the AC power supply 30 applies an AC voltage having a predetermined frequency f _C to the secondary battery 40 based on a signal from the battery controller 10.

  Next, in step S <b> 2, the AC power supply 30 performs processing for detecting the AC voltage applied to the secondary battery 40 and the response current for the AC voltage, and the detected AC voltage and response current are transmitted to the battery controller 10. The

  In step S3, the battery controller 10 calculates the AC resistance | Z | of the secondary battery 40 according to the above equation (1) based on the AC voltage and response current detected in step S2.

Next, in step S4, the battery controller 10 calculates a reversible capacity estimation range _{PC_REV} . Specifically, first, the battery controller 10 determines the AC resistance | Z | of the secondary battery 40 calculated in step S3, the frequency f _{c of the} AC voltage applied to the secondary battery 40, and the battery controller shown in FIG. Based on the relationship between the AC resistance | Z | stored in advance in 10 and the reversible capacity value Q _REV (electric double layer capacity C1), the reversible capacity value Q _{REV_imp} based on the AC resistance | Z | Then, the battery controller 10 calculates a predetermined range including the reversible capacity value Q _{REV_imp} as the reversible capacity estimation range _{PC_REV} based on the reversible capacity value Q _{REV_imp} based on the calculated AC resistance | Z |.

Here, FIG. 7A shows the relationship between the change in the reversible capacity value Q _REV and the AC resistance | Z | when the secondary battery 40 is repeatedly charged and discharged. As shown in FIG. 7A, when the secondary battery 40 is repeatedly charged and discharged, when the reversible capacity value Q _REV decreases as the secondary battery 40 deteriorates, the AC resistance decreases accordingly. | Z | will also change. In FIG. 7A, the horizontal axis can be the number of cycles, for example. As shown in FIG. 7A, for example, when the value of the AC resistance | Z | calculated in step S3 is X, the battery controller 10 causes the AC resistance | Z | Q _{REV_imp_X} is calculated as a reversible capacity value corresponding to. Then, as shown in FIG. 7A, the battery controller 10 sets the reversible capacity estimation range _{PC_REV} based on the calculated reversible capacity value Q _{REV_imp_X} . Specifically, a range of a predetermined value including the reversible capacity value Q _{REV_imp_X} is set to the reversible capacity estimation range _{PC_REV} .

  Next, in step S5, the battery controller 10 calculates the reactance -Z '' of the secondary battery 40 according to the above formulas (2) to (4) based on the AC voltage and the response current detected in step S2. Done.

In step S6, the current reversible capacity of the secondary battery 40 is determined by the battery controller 10 based on the reactance −Z ″ calculated in step S5 and the estimated reversible capacity range _{PC_REV} calculated in step S4. A process for calculating the value Q _REV is performed. Here, FIG. 7B shows the relationship between the change in the reversible capacity value Q _REV and the reactance −Z ″ when the secondary battery 40 is repeatedly charged and discharged. 7B is a graph corresponding to FIG. 7A described above. Similar to FIG. 7A, when the secondary battery 40 is repeatedly charged and discharged, the secondary battery is shown. As the reversible capacitance value Q _REV decreases with the deterioration of 40, the reactance −Z ″ also changes accordingly. In FIG. 7B, the horizontal axis can be the number of cycles, for example, as in FIG. 7A described above.

Then, as shown in FIG. 7B, for example, when the value of the reactance −Z ″ calculated in step S5 described above is Y, the battery controller 10 causes the AC resistance | Z | = Y. _Two values of Q _{REV_imp_Y1} and Q _{REV_imp_Y2} are calculated as reversible capacity values corresponding to. In contrast, the battery controller 10 refers to the estimated range _{P C_REV} reversible capacity calculated in the step _S4, of the two values of _{Q REV_imp_Y1} and _{Q REV_imp_Y2,} the value of any is the estimation range _{P C_REV} reversible capacity _Is determined, a value in the reversible capacity estimation range _{PC_REV} , that is, Q _{REV_imp_Y2} is selected, and this is calculated as the current reversible capacity value Q _REV of the secondary battery 40.

And it progresses to step S7 and the battery controller 10 performs the process which sets the largest charging / discharging electric current at the time of charging / discharging the secondary battery 40 based on the reversible capacity value _QREV calculated by step S6. Specifically, since the battery controller 10 can determine that the deterioration with time of the secondary battery 40 is progressing as the reversible capacity value Q _REV is lower, the battery controller 10 sets the maximum charge / discharge current value smaller.

As described above, the current reversible capacity value _QREV of the secondary battery 40 is calculated.

In the present embodiment, as described above, when calculating the current reversible capacity value Q _REV of the secondary battery 40, first, as shown in FIG. 7A, the AC resistance | Z | In the example shown in A), the AC resistance | Z | = X) is calculated, and the reversible capacity estimation range _{PC_REV} is set from the reversible capacity value Q _{REV_imp_X} corresponding to the AC resistance | Z |. Here, the AC resistance | Z | is the absolute value of the combined vector of the conductance Z ′ and the reactance -Z ″ as is well known, and the AC resistance | Z | is the current reversible capacity value Q of the secondary battery 40. Although there is a correlation with _REV , the reversible capacity value Q _{REV_imp_X} calculated from the AC resistance | Z | may not exactly match the current reversible capacity value Q _REV of the secondary battery 40. That is, the current reversible capacity value Q _REV of the secondary battery 40 cannot be accurately calculated from the AC resistance | Z |. Therefore, in the present embodiment, the reversible capacity estimation range _{PC_REV} is set as a range having a certain width from the reversible capacity value Q _{REV_imp_X} corresponding to the AC resistance | Z |.

On the other hand, as described above, the reactance −Z ″ has a correlation with the current reversible capacity value Q _REV of the secondary battery 40 in the same manner as the AC resistance | Z |. The reversible capacity value Q _{REV_REA} calculated from Z ″ has a property that it matches the current reversible capacity value Q _REV of the secondary battery 40 with high accuracy. However, on the other hand, as shown in FIG. _7B , two values of Q _{REV_imp_Y1} and Q _{REV_imp_Y2} are usually calculated as the reversible capacity value calculated from the reactance −Z ″ due to its nature. .

Therefore, in the present embodiment, first, the reversible capacity estimation range _{PC_REV} is set as a range having a certain width from the reversible capacity value Q _{REV_imp_X} corresponding to the AC resistance | Z |, and is calculated from the reactance −Z ″. Of the two values Q _{REV_imp_Y1} and Q _{REV_imp_Y2} that are the reversible capacity values to be _generated , a value that falls within the range of the reversible capacity estimation range _{PC_REV} is selected, whereby the current reversible capacity value of the secondary battery 40 is selected. Q _REV is calculated. According to this embodiment, the current reversible capacity value Q _REV of the secondary battery 40 can be calculated with high accuracy by such a method.

Next, the method of setting the frequency f _c of the AC voltage by the AC power source 30 is applied to the secondary battery 40 will be described. In particular, in the present embodiment, in order to detect the change over time of the reversible capacity value Q _REV of the secondary battery 40 and thereby properly grasp the deterioration state of the secondary battery 40, it is applied to the secondary battery 40. as the frequency f _c of the AC voltage, current reversible capacity value Q _REV of the secondary battery _40, i.e., the electric double layer capacitor C1 and select appropriate detectable frequency, using the frequency f _c chosen, above It is desirable to perform the measurement. In particular, in order to properly detect the current reversible capacity value Q _REV of the secondary battery 40, that is, the electric double layer capacity C 1, charging of the electric double layer capacity is completed, and the rate is limited by the diffusion of the reactant. It is not desirable to apply an AC voltage having a frequency corresponding to such a diffusion region. Therefore, in the following, the method of setting the frequency f _c of the AC voltage applied to the secondary battery 40 will be described.

Figure 8 is a diagram for explaining a method of setting the frequency f _c of the AC voltage in the present embodiment, FIG. 8, the secondary battery 40 which is not degraded over time, such as prior to use, a constant voltage The time change of the current value is shown.

As shown in FIG. 8, when a constant voltage is applied to the secondary battery 40 that has not deteriorated with time, such as before use, first, when application of the constant voltage is started at time t ₀ , until time t ₁ , The current decays with a predetermined slope L1 (first stage). Then, from time _{t 1} to time _{t 2,} will the current loose gradient L2 than the slope L1 of the first stage is attenuated (second stage), then from the time _{t 2} to time _{t 3,} the The current attenuates at a slope L3 that is more gentle than the slope L2 in the second stage (third stage). Here, the first stage is an electric double layer region in which a reaction by an electric double layer occurs, the second step is an electrode reaction region in which a reaction by positive and negative electrodes occurs, and the third step is a reaction by diffusion. It can be defined as the diffusion region that occurs. That is, the first stage and the second stage can be defined as non-diffusion areas, and the third stage can be defined as a diffusion area.

On the other hand, in the present embodiment, when the frequency f _{c of the} alternating voltage is t _α ≦ t ₂ and t _β ≦ t ₁ , f _c = 1 / t _α , preferably f _c = 1. / T _β . That is, in the present embodiment, when a constant voltage is applied to the secondary battery 40 that has not deteriorated with time such as before use as shown in FIG. 8, the time t _{0 to} t ₂ , which is a non-diffusion region, in particular, In order to appropriately detect the reaction occurring at the time t _{0 to} t ₁ , the frequency f _{c of the} AC voltage is set in the above range. According to this embodiment, by setting the frequency f _c of the AC voltage in the above range, it is possible to properly detect the electric double layer capacitor C1 of the rechargeable battery 40, as a result, the current of the secondary battery 40 The reversible capacity value Q _REV of can be calculated with high accuracy.

Alternatively, as a method of setting the frequency f _c of the AC voltage, instead of the method, it may be adopted the following method. Here, FIG. 9 is a diagram for explaining another method of setting the frequency f _c of the AC voltage in the present embodiment, FIG. 9, the secondary battery 40 which is not degraded over time, such as prior to use 5 shows a graph in which an AC voltage is applied while changing the frequency, and conductance Z ′ and reactance −Z ″ are plotted.

As shown in FIG. 9, when an AC voltage is applied to a secondary battery 40 that has not deteriorated over time, such as before use, while changing the frequency, the conductance Z ′ and the reactance −Z ′ are applied. When 'is plotted, a Nyquist plot is drawn. In such a Nyquist plot, it can be determined that the lower frequency side than the frequency f _α shown in FIG. 9 is based on the diffusion region, while the higher frequency side than the frequency f _α is based on the non-diffusion region. Can be judged. Therefore, in this embodiment, the frequency f _c of the AC voltage is set to a frequency above the frequency f _alpha shown in FIG. Thus, according to the present embodiment, the electric double layer capacity C1 of the secondary battery 40 can be appropriately detected, and as a result, the current reversible capacity value Q _REV of the secondary battery 40 can be accurately detected. It is possible to calculate.

Alternatively, as a method of setting the frequency f _{c of the} AC voltage, instead of the above-described methods, a secondary battery 40 that is actually deteriorated with time is prepared, and the frequency of the secondary battery 40 that is actually deteriorated with time is determined. In the same manner as in FIG. 9, the conductance Z ′ and the reactance −Z ″ are plotted for the secondary battery 40 that is deteriorated with time by applying an AC voltage while changing the AC voltage, and the AC voltage is based on the obtained plot. how to set the frequency f _c may be employed. According to this method, by using the actual secondary battery 40 obtained by time degradation, to set the frequency f _c of the AC voltage, it is possible to properly detect the electric double layer capacitor C1 of the rechargeable battery 40 As a result, the current reversible capacity value _QREV of the secondary battery 40 can be calculated with high accuracy.

In the present embodiment, an AC voltage is applied to the secondary battery 40, an AC resistance | Z | and a reactance −Z ″ are calculated when the AC voltage is applied, and a reversible capacity corresponding to the AC resistance | Z | the value _{Q REV_imp,} as a range having a certain width, and sets the estimated range _{P C_REV} of reversible capacity, of the two reversible capacity values calculated from the reactance -Z '', the range of the estimated range _{P C_REV} reversible capacity The inner value is selected, and thereby the current reversible capacity value Q _REV of the secondary battery 40 is calculated. Therefore, according to the present embodiment, the secondary battery 40 of the secondary battery 40 based on the electric double layer capacity C1 is not affected by the resistance deterioration in the secondary battery 40 due to the increase in the resistance of the secondary battery 40. The current reversible capacity value Q _REV can be appropriately calculated. In particular, according to the present embodiment, since the current reversible capacity value Q _REV of the secondary battery 40 based on the electric double layer capacity C1 can be appropriately calculated, a charge / discharge capacity that can be used purely and stably. Can be grasped appropriately. In addition, according to the present embodiment, the maximum charge / discharge current of the secondary battery 40 is set in order to set the maximum charge / discharge current of the secondary battery 40 according to the current reversible capacity value Q _REV of the secondary battery 40. Thus, it is possible to set the secondary battery 40 to an appropriate one according to the degree of deterioration.

  Here, in the secondary battery, the deterioration modes mainly include resistance deterioration (deterioration due to an increase in resistance component) and capacity deterioration (deterioration due to a decrease in reversible capacity value). When deterioration occurs, there is a characteristic that the phase component changes. Therefore, as in the conventional technique such as the technique described in Patent Document 1 (Japanese Patent Laid-Open No. 2008-107168) described above, only the response current in a specific phase range is integrated, and based on the obtained integrated value, two values are integrated. In the technique for calculating the dischargeable capacity of the secondary battery, there is a problem that it is not possible to distinguish between resistance deterioration and capacity deterioration. On the other hand, according to this embodiment, such a problem can be effectively solved by adopting the above configuration.

  In the above-described embodiment, the AC voltage application device 30 is the AC voltage application unit of the present invention, and the battery controller 10 is the detection unit, AC resistance calculation unit, imaginary value calculation unit, first calculation unit, and second unit of the present invention. It corresponds to a calculation means, a third calculation means, and a charge / discharge current control means, respectively.

  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, the configuration in which the AC voltage is applied to the secondary battery 20 by the AC voltage application device 30 is illustrated. However, for example, when the battery control system according to this embodiment is used in a vehicle. Instead of using the AC voltage application device 30, a configuration may be adopted in which the secondary battery 40 is connected to an inverter circuit and an AC voltage is applied via the inverter circuit. By setting it as such a structure, the alternating voltage application apparatus 30 can be abbreviate | omitted.

  In the above-described embodiment, the battery control system including only one secondary battery 40 has been described as an example. However, the battery control device of the present invention is naturally applicable to a battery module including a plurality of secondary batteries 40. Is possible.

DESCRIPTION OF SYMBOLS 10 ... Battery controller 20 ... Charging / discharging apparatus 30 ... AC voltage application apparatus 40 ... Secondary battery

Claims (9)

AC voltage application means for applying an AC voltage of an arbitrary frequency to the secondary battery,
Detecting means for detecting an alternating voltage and a response current to the alternating voltage when the alternating voltage is applied;
AC resistance calculating means for calculating an AC resistance value of the secondary battery based on the AC voltage and the response current detected by the detecting means;
A phase difference of the response current with respect to the AC voltage is calculated based on the AC voltage and the response current detected by the detection means, and an imaginary value of the AC resistance value is calculated based on the calculated phase difference. Imaginary value calculation means;
Based on the AC resistance value and information indicating the relationship between the time-dependent change in the AC resistance value acquired in advance and the time-dependent change in the reversible capacity of the secondary battery, the reversible capacity value based on the AC resistance of the secondary battery. First calculating means for calculating
Based on the imaginary value and information indicating the relationship between the temporal change of the imaginary value acquired in advance and the temporal change of the reversible capacity of the secondary battery, the reversible capacity value based on the imaginary value of the secondary battery is calculated. Second calculating means for
Based on the reversible capacity value based on the AC resistance calculated by the first calculating means and the reversible capacity value based on the imaginary value calculated by the second calculating means, the current reversible capacity value of the secondary battery is calculated. A battery control device comprising: a third calculation means for calculating. The battery control device according to claim 1,
The third calculation means includes
From the reversible capacity value based on the AC resistance, estimate the range where the current reversible capacity value of the secondary battery exists,
A battery control device that calculates a reversible capacity value that falls within the range among reversible capacity values based on the imaginary value as a current reversible capacity value of the secondary battery. The battery control device according to claim 1 or 2,
The battery control device characterized in that the frequency of the alternating voltage applied by the alternating voltage applying means is set to a frequency determined from the behavior of the response current when a constant voltage is applied to the secondary battery before change with time. The battery control device according to claim 3, wherein
The response current from the non-diffusion region of the secondary battery, which is obtained from the behavior of the response current when a constant voltage is applied to the secondary battery before change with time, is the frequency of the alternating voltage applied by the alternating voltage application means. A battery control device characterized in that the frequency is set to be obtained. The battery control device according to claim 1 or 2,
The frequency of the AC voltage applied by the AC voltage applying means is set to a frequency determined from the behavior of the secondary battery when an AC voltage is applied while changing the frequency to the secondary battery before aging. A battery control device. The battery control device according to claim 5,
The response current from the non-diffusion region of the secondary battery is obtained by applying the alternating voltage while changing the frequency of the alternating voltage applied by the alternating voltage application means to the secondary battery before aging. A battery control device characterized in that the frequency is set to be obtained. The battery control device according to claim 1 or 2,
The frequency of the AC voltage applied by the AC voltage applying means is set to a frequency determined from the behavior of the secondary battery when an AC voltage is applied to the secondary battery after change over time. Control device. The battery control device according to claim 1,
The AC voltage application means applies an AC voltage converted by an inverter circuit to the secondary battery. The battery control device according to claim 1,
The battery control apparatus further comprising charge / discharge current control means for controlling charge / discharge current of the secondary battery according to a current reversible capacity value of the secondary battery calculated by the third calculation means. .

Images