JP2019201464A - Deterioration diagnostic system and deterioration diagnostic method - Google Patents

Abstract

To provide a deterioration diagnostic system capable of highly accurately diagnosing a degree of deterioration of a lead storage battery, and a deterioration diagnostic method.SOLUTION: A deterioration diagnosis system 100 includes: a control device 20 for charging a lead storage battery 10 up to a predetermined voltage; an open circuit voltage calculation unit 31 for calculating an open circuit voltage in a fully charged state of the lead storage battery 10; an internal resistance calculation unit 32 for calculating internal resistance of the lead storage battery 10; and a discharge capacity calculation unit 33 for calculating a discharge capacity of the lead storage battery 10 based on the open circuit voltage in the fully charged state and the internal resistance.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a deterioration diagnosis system and a deterioration diagnosis method.

  In recent years, sealed secondary batteries represented by lithium ion secondary batteries have been used as power sources for mobile devices such as mobile phones and laptop computers, electric vehicles such as electric vehicles and hybrid vehicles, and backup power sources for uninterruptible power supplies. , Etc.

  For example, as a deterioration diagnosis method for a lead storage battery, a method using the internal impedance of the lead storage battery, a method using the voltage of the lead storage battery after discharging about several percent of the nominal capacity (see Non-Patent Document 1), both A method to use (see Non-Patent Document 2) and the like are known.

IEEJ Transaction 87, No. 5, VOL. 107-D, P606 Journal of the Electrical Equipment Society of Japan, 1993, No. 12, VOL. 13, P1247

  However, the conventional deterioration diagnosis method for lead-acid batteries has a problem that the degree of deterioration cannot be diagnosed with high accuracy. In particular, lead storage batteries used as a backup power source are required to secure a certain amount of discharge time in the event of a power failure. Therefore, when performing a deterioration diagnosis, the discharge capacity, which is an indicator of the degree of deterioration, must be accurately set. To be calculated.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a deterioration diagnosis system and a deterioration diagnosis method capable of diagnosing the degree of deterioration of a lead storage battery with high accuracy.

  In order to solve the above-described problems, the present invention provides a control device for charging a lead storage battery to a predetermined voltage, an open circuit voltage calculation unit for calculating an open circuit voltage in a fully charged state of the lead storage battery, and an interior of the lead storage battery. An internal resistance calculation unit that calculates resistance, and a discharge capacity calculation unit that calculates a discharge capacity of the lead-acid battery based on the open circuit voltage and the internal resistance in the fully charged state.

  ADVANTAGE OF THE INVENTION According to this invention, the deterioration diagnostic system which can diagnose the deterioration degree of lead acid battery with high precision can be provided.

It is a figure which shows an example of a structure of the deterioration diagnostic system which concerns on 1st Embodiment. It is a figure which shows an example of the current voltage characteristic of the lead acid battery in the deterioration diagnostic system which concerns on 1st Embodiment. It is a figure which shows an example of the current voltage characteristic of the lead acid battery in the deterioration diagnostic system which concerns on 1st Embodiment. It is a figure which shows an example of the equivalent circuit used for the alternating current impedance measurement of the lead acid battery in the deterioration diagnostic system which concerns on 1st Embodiment. It is a figure which shows an example of the Cole-Cole plot using the equivalent circuit used for the alternating current impedance measurement of the lead acid battery in the deterioration diagnostic system which concerns on 1st Embodiment. It is a flowchart which shows an example of the degradation diagnostic method in the degradation diagnostic system which concerns on 1st Embodiment. It is a figure which shows an example of the current voltage characteristic of the lead acid battery in the deterioration diagnostic system which concerns on 3rd Embodiment. It is a figure which shows an example of the relationship between the discharge electricity amount of a lead acid battery, and a voltage in the deterioration diagnostic system which concerns on 4th Embodiment.

  Hereinafter, the radio | wireless communications system which concerns on embodiment is demonstrated. The drawings referred to in the following description schematically show the embodiment, and therefore, the scale, interval, positional relationship, etc. of each member are exaggerated, or some of the members are not shown. There is a case. Moreover, in the following description, the same name and the code | symbol are showing the same or the same member in principle, and shall abbreviate | omit detailed description suitably.

<< First Embodiment >>
[Deterioration diagnosis system]
First, the configuration of the deterioration diagnosis system 100 according to the present embodiment will be described with reference to FIG.

As shown in FIG. 1, the deterioration diagnosis system 100 includes a lead storage battery 10, a voltage / current control device (control device) 20, a deterioration diagnosis device 30, a storage unit 40, and an output unit 50. The deterioration diagnosis device 30 includes an open circuit voltage calculation unit 31, an internal resistance calculation unit 32, a discharge capacity calculation unit 33, and a deterioration diagnosis unit 34.
In the following description, a lead storage battery will be described as an example of a sealed secondary battery applied to the deterioration diagnosis system 100. However, the type of the sealed secondary battery is not limited to the lead storage battery. For example, a lithium ion battery, an alkaline storage battery, a nickel metal hydride storage battery, or the like may be used.

The voltage / current control device 20 controls the charge / discharge voltage and charge / discharge current of the lead storage battery 10. The voltage / current control device 20 charges the lead storage battery 10 to a predetermined voltage by a charging method such as float charging or trickle charging. This predetermined voltage is preferably higher than at least the open circuit voltage of the lead storage battery 10 in the fully charged state. Furthermore, the voltage / current control device 20 controls the charge / discharge voltage and the charge / discharge current of the lead storage battery 10 based on information regarding the degree of deterioration of the lead storage battery 10 input from the output unit 50. In this specification, “full charge state” means that sulfate sulfate ionizable lead sulfate (PbSO ₄ ) does not remain on the positive electrode and the negative electrode of the lead storage battery 10 and can be used for charge / discharge reactions. (SO ₄ ²⁻ ) means a state in which all of (SO ₄ ²⁻ ) is present in the electrolyte (H ₂ SO ₄ )

  The degradation diagnosis apparatus 30 is configured by, for example, a CPU (Central Processing Unit). The deterioration diagnosis device 30 reads various control programs stored in the storage unit 40, develops them in a work area, and executes the control program to control each component and perform various processes.

  The open circuit voltage calculation unit 31 calculates the open circuit voltage when the lead storage battery 10 is fully charged. For example, the open circuit voltage calculation unit 31 calculates the voltage of the lead storage battery 10 after the lead storage battery 10 is charged by the voltage / current control device 20 and a predetermined time has elapsed as the open circuit voltage in the fully charged state of the lead storage battery 10. . Further, for example, the open circuit voltage calculation unit 31 uses the voltage of the lead storage battery 10 after the charging from the voltage / current control device 20 to the lead storage battery 10 is stopped for a predetermined time as the open circuit voltage in the fully charged state of the lead storage battery 10. Calculate as That is, the method by which the open circuit voltage calculation unit 31 calculates the open circuit voltage in the fully charged state of the lead storage battery 10 is not particularly limited.

  For example, the open circuit voltage calculation unit 31 charges and discharges the lead storage battery 10 with a plurality of predetermined currents (for example, 15 [A], 20 [A], and 25 [A]) for a predetermined time (for example, 5 [s]). Based on the relationship between the voltage (for example, 2.18 [V], 2.175 [V], 2.17 [V]) of the lead storage battery 10 and a plurality of predetermined currents, An open circuit voltage (for example, 2.197 [V]) in a fully charged state is calculated (see FIGS. 2 and 3).

FIG. 2 is a diagram illustrating an example of current-voltage characteristics of the lead storage battery 10 when the lead storage battery 10 is charged and discharged for a predetermined time with a plurality of predetermined currents. The horizontal axis indicates time [s], the left vertical axis indicates current [A], and the right vertical axis indicates voltage [V].
That is, FIG. 2 shows that the lead-acid battery 10 is discharged from the fully charged state at 15 [A] for 10 [s], and then recharged again, and discharged from the fully charged state at 20 [A] for 10 [s]. 3 shows the current-voltage characteristics of the lead storage battery 10 when the battery is fully charged again and discharged at 25 [A] for 10 [s] from the fully charged state.
As shown in FIG. 2, the voltage of the lead storage battery 10 after discharging the lead storage battery 10 at, for example, 15 [A] for 5 [s] is 2.18 [V]. The voltage of the lead storage battery 10 after discharging the lead storage battery 10 at, for example, 20 [A] for 5 [s] is 2.175 [V]. For example, the voltage of the lead storage battery 10 after discharging the lead storage battery 10 at 25 [A] for 5 [s] is 2.17 [V].

FIG. 3 is a diagram illustrating an example of current-voltage characteristics of the lead storage battery 10 when the lead storage battery 10 is discharged with a plurality of predetermined currents for a predetermined time. The horizontal axis indicates the discharge current [A], and the vertical axis indicates the voltage [V].
In the current-voltage characteristic shown in FIG. 3, the point A is a plot of the voltage 2.18 [V] of the lead storage battery 10 after discharging the discharge current 15 [A] and 5 [s]. Point B is a plot of the voltage 2.175 [V] of the lead storage battery 10 after discharging the discharge current 20 [A], 5 [s]. Point C is a plot of the voltage 2.17 [V] of the lead storage battery 10 after discharging the discharge current 25 [A], 5 [s].
The open circuit voltage calculation unit 31 can calculate the open circuit voltage of the lead storage battery 10 in a fully charged state based on a straight line connecting the points A, B, and C. That is, in the example shown in FIG. 3, the open circuit voltage V _f in the fully charged state of the lead storage battery 10 is the intersection of the straight line connecting points A, B, and C and the vertical axis (discharge current 0 [A]). For example, it becomes 2.197 [V].
Since the open circuit voltage _Vf in the fully charged state of the lead storage battery 10 is preferably slightly lower than the voltage in the float charged state of the lead storage battery 10, the open circuit voltage _Vf in the fully charged state of the lead storage battery 10 is, for example, 2.197 [V], the voltage of the lead storage battery 10 in the float charge state is preferably about 2.230 [V].

As described above, the open circuit voltage calculation unit 31 plots the relationship between the voltage of the lead storage battery 10 and the discharge current when the lead storage battery 10 is discharged with a plurality of predetermined currents for a predetermined time on a graph. It is also possible to calculate the open circuit voltage in the fully charged state of the lead storage battery 10 by connecting points and performing linear regression. Alternatively, it is possible to calculate the open circuit voltage by substituting the intersection _Vf into a predetermined function without considering the intersection _Vf with the vertical axis shown in FIG. 3 as an open circuit voltage. The open circuit voltage calculation unit 31 calculates the open circuit voltage in the fully charged state of the lead storage battery 10 by such a method, so that the backup of the lead storage battery used as a backup power source is also provided. It is possible to calculate a highly accurate value without impairing the function.

The internal resistance calculation unit 32 calculates the internal resistance of the lead storage battery 10. Examples of the internal resistance include a charge transfer resistance R _ct .
For example, the internal resistance calculation unit 32 calculates the internal resistance based on the AC impedance of the lead storage battery 10 at a plurality of frequencies. The frequency may include at least two or more different frequencies, and preferably includes a frequency of 100 Hz or more and a frequency of less than 100 Hz, and includes a frequency of 100 Hz or more and a frequency of 3 Hz or less. It is more preferable. Note that the current amplitude, voltage amplitude, number of repetitions, and the like are not particularly limited, and are arbitrarily set.

For example, when the frequency is 3 levels or more, the internal resistance calculation unit 32 can calculate the internal resistance by performing fitting calculation using the equivalent circuit shown in FIG.
FIG. 4 is a diagram showing an example of an equivalent circuit used for measuring the AC impedance of the lead storage battery. In the equivalent circuit shown in FIG. 4, the resistance corresponds to the electrolyte resistance R _s and the charge transfer resistance R _ct , and the capacity corresponds to the electric double layer capacity C _d . In addition, the structure of the equivalent circuit used for the alternating current impedance measurement of the lead storage battery 10 is not limited to the structure of the equivalent circuit shown in FIG. For example, the charge transfer resistance R _ct may be replaced with a series connection of the charge transfer resistance R _ct and the Warburg impedance W to include the Warburg impedance W. For example, a portion of the electrolyte resistance R _s, a series circuit of an inductance component L and the electrolyte resistance R _s, or may be configured to replace a parallel circuit of an inductance component L and the electrolyte resistance R _s.

For example, when the frequency is 2 levels, the internal resistance calculation unit 32 calculates the absolute value (or real part) of the relatively high frequency impedance from the absolute value (or real part) of the relatively low frequency impedance. The internal resistance can be calculated by subtracting.
That is, the absolute value of the low frequency impedance is approximately the sum of the electrolyte resistance R _s and the charge transfer resistance R _ct (R _s + R _ct ), and the absolute value of the high frequency impedance is approximately the electrolyte resistance R _s. It becomes. By utilizing this, the internal resistance calculation unit 32 calculates the sum (R _s + R _ct ) of the electrolyte resistance R _s and the charge transfer resistance R _ct which are absolute values (or real parts) of relatively low frequency impedance. ), The internal resistance (charge transfer resistance R _ct ) can be calculated by subtracting the electrolyte resistance R _s , which is the absolute value (or real part) of the relatively high frequency impedance.

  Further, for example, when the frequency is two levels, the internal resistance calculation unit 32 may calculate the internal resistance using the Cole-Cole plot shown in FIG. Specifically, the internal resistance calculation unit 32 acquires an AC impedance measured when the voltage / current control device 20 connected to the lead storage battery 10 applies an AC voltage or an AC current to the lead storage battery 10. The internal resistance calculator 32 plots the AC impedance of the lead storage battery 10 measured at a plurality of frequencies (for example, a relatively high frequency and a relatively low frequency) on a complex plane (Cole-Cole plot). Using this Cole-Cole plot, the internal resistance is calculated.

FIG. 5 is a diagram illustrating an example of a Cole-Cole plot using an equivalent circuit used for measuring the AC impedance of the lead storage battery 10.
In the Cole-Cole plot shown in FIG. 5, a semicircular arc C is a locus of AC impedance of the lead storage battery 10 when the frequency is changed. The real axis intercept of the semicircular arc C is the electrolyte resistance R _s , the sum of the electrolyte resistance R _s and the charge transfer resistance R _ct (R _s + R _ct ). The diameter of the semicircular arc C is the charge transfer resistance _Rct . The radius of the semicircular arc C is ½ of the charge transfer resistance _Rct .
The AC impedance measured at a high frequency is [real part, imaginary part]: (x _h , y _h ), and the AC impedance measured at a low frequency is [real part, imaginary part]: (x _l , y _l ).
When the center of the semicircular arc C is (x _c , 0), the real axis intercept (x _h , 0) of the semicircular arc C and the AC impedance (x ₁ , y ₁ ) measured at a low frequency are Assuming that it is located at, the radius of the semicircular arc C can be expressed by equation (1).
Holds.
That is, the internal resistance calculation unit 32 uses the Cole-Cole plot shown in FIG. 5, the real part x _h of the AC impedance measured at a high frequency, the real part x _l of the AC impedance measured at a low frequency, and the low based on the imaginary part y _l AC impedance measured at a frequency, the center of the semicircular arc C, and the charge transfer resistance R _ct can be calculated.
When the charge transfer resistance R _ct is assumed to be sufficiently larger than the electrolyte resistance R _s , the magnitude of the charge transfer resistance R _ct may be determined based on the imaginary part y having a predetermined frequency. For example, R _ct can be calculated by substituting the measured value of the imaginary part y into a predetermined function indicating the relationship between the imaginary part y and the charge transfer resistance R _ct .
The method by which the internal resistance calculation unit 32 calculates the internal resistance (for example, charge transfer resistance R _ct ) is not particularly limited.

The discharge capacity calculation unit 33 includes an open circuit voltage V _f in a fully charged state calculated by the open circuit voltage calculation unit 31 and an internal resistance R (for example, charge transfer resistance R _ct ) calculated by the internal resistance calculation unit 32. Based on the above, the discharge capacity Q is calculated.

The discharge capacity calculation unit 33 can calculate the discharge capacity Q using, for example, a relational expression as shown in Expression (2). That is, the discharge capacity calculation unit 33 calculates the discharge capacity Q based on the open circuit voltage V _f , the internal resistance R, the constant a ₁ , and the constant a ₂ in the fully charged state.

The discharge capacity calculation unit 33 can calculate the discharge capacity Q using, for example, a relational expression as shown in Expression (3). That is, the discharge capacity calculation unit 33 determines the discharge capacity Q based on the open circuit voltage V _f , the charge transfer resistance R _ct , the electrolyte resistance R _s , the constant a ₁ , the constant a ₂ , and the constant a ₃ in the fully charged state. Is calculated.

For example, the discharge capacity calculation unit 33 can calculate the discharge capacity Q using a relational expression as shown in Expression (4). That is, the discharge capacity calculation unit 33 is based on the open circuit voltage V _f , the charge transfer resistance R _ct , the electrolyte resistance R _s , the discharge current I, the constant a ₁ , the constant a ₂ , and the constant a ₃ in the fully charged state. The discharge capacity Q is calculated.

  The discharge capacity calculation unit 33 can calculate the discharge capacity Q using a relational expression that is arbitrarily set in addition to the above formulas (2), (3), and (4).

  The deterioration diagnosis unit 34 diagnoses the degree of deterioration of the lead storage battery 10 based on the discharge capacity Q calculated by the discharge capacity calculation unit 33. Then, the degradation diagnosis unit 34 outputs the diagnosis result to the output unit 50. The lead storage battery 10 has a reduced discharge capacity Q as it deteriorates. Therefore, for example, the deterioration diagnosis unit 34 diagnoses that the deterioration degree of the lead storage battery 10 is large if the decrease in the discharge capacity Q is large, and if the deterioration degree of the lead storage battery 10 is small if the decrease in the discharge capacity Q is small. Diagnose.

  The storage unit 40 is used as a working storage area for the control unit 11 to execute a control program. The storage unit 40 includes, for example, a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, and includes a control program executed by the deterioration diagnosis device 30, various data necessary for execution of the control program, various information, Memorize etc. Further, the storage unit 40 includes various values, voltage values, current values, measured AC impedance values, discharge electricity amounts, open circuit voltage data tables, open circuit voltage curves, and the like calculated by the degradation diagnosis device 30. Remember.

  The output unit 50 outputs information on the degree of deterioration of the lead storage battery 10 to the voltage / current control device 20 based on the discharge capacity Q input from the deterioration diagnosis device 30. The information on the degree of deterioration of the lead storage battery 10 is, for example, information such as a large decrease in the discharge capacity Q and a large degree of deterioration of the lead storage battery 10, a small decrease in the discharge capacity Q and a small degree of deterioration of the lead storage battery 10. .

According to the deterioration diagnosis system 100 according to the present embodiment, the open circuit voltage and the internal resistance in the fully charged state, which have a large correlation with the discharge capacity of the lead storage battery 10, are calculated, and based on these values, the lead storage battery 10 A discharge capacity that is a deterioration index is calculated. Thereby, since it was difficult to accurately grasp the discharge capacity of the lead storage battery 10, the conventional problem that the degree of deterioration of the lead storage battery 10 cannot be accurately diagnosed is solved, and the degree of deterioration of the lead storage battery 10 is highly accurate. It is possible to realize the deterioration diagnosis system 100 that can be diagnosed quickly.
Especially for lead-acid batteries used as a backup power source, necessary measurements are made in a short time and with a small amount of discharge from the state of float charge or trickle charge, and the discharge capacity (backup time at power failure) Can be calculated. Thereby, it is possible to realize the deterioration diagnosis system 100 that can accurately determine the replacement time of the lead storage battery without impairing the backup function.

<< Deterioration diagnosis method of deterioration diagnosis system 100 >>
Next, a deterioration diagnosis method in the deterioration diagnosis system 100 according to the present embodiment will be described with reference to FIG. FIG. 6 is a flowchart illustrating an example of the deterioration diagnosis method in the deterioration diagnosis system 100. Note that the flowchart shown in FIG. 6 is merely an example, and the present invention is not limited to this method.

  In step S201, the deterioration diagnosis system 100 charges the lead storage battery 10 to a predetermined voltage by a charging method such as float charging or trickle charging. Float charging is a charging method that maintains the lead storage battery 10 in a fully charged state by compensating for the self-discharge of the positive electrode plate and the negative electrode plate in the lead storage battery 10. In addition, trickle charging means that when the lead storage battery 10 is in a fully charged state, a small amount of current is continuously supplied to compensate for self-discharge of the positive electrode plate and the negative electrode plate in the lead storage battery 10 to keep the lead storage battery 10 in a fully charged state. It is a charging method.

In step S202, the deterioration diagnosis system 100 calculates an open circuit voltage in a fully charged state. The degradation diagnosis system 100 is, for example, a voltage of 2.18 [V] of the lead storage battery 10 when the lead storage battery 10 is discharged at 15 [A] for 5 [s], and the lead storage battery 10 at 5 [s] at 20 [A]. ] The voltage 2.175 [V] of the lead storage battery 10 when discharged, the voltage 2.17 [V] of the lead storage battery 10 when discharging the lead storage battery 10 at 25 [A] for 5 [s], The graph is plotted with current [A] on the axis and voltage [V] on the vertical axis. Then, the deterioration diagnosis system 100 calculates the intersection of the straight line connecting the points and the vertical axis (discharge current 0 [A]) as the open circuit voltage V _f in the fully charged state.

  In step S203, the deterioration diagnosis system 100 measures AC impedance. The degradation diagnosis system 100 applies an AC voltage or an AC current to the lead storage battery 10 and changes the frequency from a relatively low frequency to a relatively high frequency, for example, to thereby change the lead storage battery 10 at a relatively low frequency. The AC impedance of the lead storage battery 10 at a relatively high frequency is measured.

  In step S204, the degradation diagnosis system 100 calculates an internal resistance based on the AC impedance. For example, the degradation diagnosis system 100 uses the Cole-Cole plot to calculate the real part of the AC impedance measured at a high frequency, the real part of the AC impedance measured at a low frequency, and the imaginary of the AC impedance measured at a low frequency. The charge transfer resistance is calculated based on the part.

In step S205, the degradation diagnosis system 100 determines that the fully charged open circuit voltage V _f calculated by the open circuit voltage calculation unit 31 and the internal resistance calculated by the internal resistance calculation unit 32 (for example, the charge transfer resistance R _ct , The discharge capacity Q is calculated based on the electrolyte resistance R _s or the like.

  In step S <b> 205, the deterioration diagnosis system 100 diagnoses the degree of deterioration of the lead storage battery 10 based on the discharge capacity Q calculated by the discharge capacity calculation unit 33.

  By performing the processing as described above, the deterioration diagnosis system 100 can accurately calculate the discharge capacity and diagnose the degree of deterioration of the lead storage battery 10 based on the discharge capacity. Thereby, the deterioration diagnosis system 100 which can diagnose the deterioration degree of the lead storage battery 10 with high precision is realizable.

<< Second Embodiment >>
Next, the deterioration diagnosis system 100A according to the second embodiment will be described. Note that the degradation diagnosis system 100A shown in the second embodiment is merely an example, and is not limited to this configuration.

The deterioration diagnosis system 100A according to the second embodiment is different from the deterioration diagnosis system 100 according to the first embodiment in that the discharge capacity calculation unit 33 has an overvoltage ΔV in the fully discharged state, a lower limit voltage V ₁ of the lead storage battery 10, The discharge capacity Q is calculated by further using

  The discharge capacity calculation unit 33 can calculate the discharge capacity Q using, for example, relational expressions as shown in Expression (5), Expression (6), and Expression (7).

First, the discharge capacity calculation unit 33 calculates the overvoltage ΔV in the fully discharged state using, for example, a relational expression as shown in Expression (5). That is, the discharge capacity calculation unit 33 calculates the overvoltage ΔV in all discharge states based on the electrolyte resistance R _s , the constant a ₀ , the constant a ₁ , the charge transfer resistance R _ct , and the discharge current I.

Then, the discharge capacity calculating portion 33, for example, by using a relational expression shown in equation (6), calculates the open-circuit voltage V _e at the full discharge state. That is, the discharge capacity calculating portion 33, an overvoltage ΔV in all discharge state, the lower limit voltage V ₁ of the lead-acid battery _10, on the basis, calculates an open circuit voltage V _e at the full discharge state. The lower limit voltage V ₁ of the lead-acid battery 10, the voltage of the lead-acid battery 10 at the time of discharge is completed.

Finally, the discharge capacity calculation unit 33 calculates the discharge capacity Q using a relational expression as shown in Expression (7), for example. That is, the discharge capacity calculation unit 33 calculates the discharge capacity Q based on the open circuit voltage V _f in the fully charged state, the open circuit voltage V _e in the fully discharged state, and the constant a ₀ .
The discharge capacity calculating portion 33, quadratic equation voltage difference shown in _{(7) (V f -V e} ), cubic, exponential, by alone or combining such logarithmic function, discharge capacity Q may be calculated.

  The deterioration diagnosis system 100A also diagnoses the degree of deterioration of the lead storage battery 10 with high accuracy by calculating the discharge capacity Q using the above-described relational expressions, the expressions (5), (6), and (7). be able to.

According to the deterioration diagnosis system 100A according to the present embodiment, the open circuit voltage and the internal resistance in a fully charged state, which have a large correlation with the discharge capacity of the lead storage battery 10, are calculated, and based on these values, the lead storage battery 10 A discharge capacity that is a deterioration index is calculated. Thereby, since it was difficult to accurately grasp the discharge capacity of the lead storage battery 10, the conventional problem that the degree of deterioration of the lead storage battery 10 cannot be accurately diagnosed is solved, and the degree of deterioration of the lead storage battery 10 is highly accurate. It is possible to realize a deterioration diagnosis system 100A that can be diagnosed quickly.
Especially for lead-acid batteries used as a backup power source, necessary measurements are made in a short time and with a small amount of discharge from the state of float charge or trickle charge, and the discharge capacity (backup time at power failure) Can be calculated. Thereby, it is possible to realize the deterioration diagnosis system 100A that can accurately determine the replacement time of the lead storage battery without impairing the backup function.

<< Third Embodiment >>
Next, a deterioration diagnosis system 100B according to the third embodiment will be described. The deterioration diagnosis system 100B shown in the third embodiment is merely an example, and is not limited to this configuration.

The deterioration diagnosis system 100B according to the third embodiment is different from the deterioration diagnosis system 100 according to the first embodiment in that the open circuit voltage calculation unit 31 uses a predetermined discharge current value I ₀ set in advance. The open circuit voltage _Vf when the lead storage battery 10 is fully charged is calculated.

The open circuit voltage calculation unit 31 calculates the open circuit voltage _Vf in the fully charged state of the lead storage battery 10 using, for example, the relational expressions as shown in Expression (8) and Expression (9).

First, the open circuit voltage calculation unit 31 discharges the lead storage battery 10 at a constant discharge current value for a predetermined time, and shows the relationship between the discharge time and the voltage of the lead storage battery 10 corresponding to the discharge time. Is plotted in a graph with time [s] and the vertical axis with voltage [V]. For example, as shown in FIG. 7, the open circuit voltage calculating unit 31, the voltage V ₁ of the case where the lead-acid battery 10 is discharging time t ₁ discharged at a constant discharge current value I _0, lead-acid battery 10 a constant discharge current Voltage V ₂ when discharge time t _{2 is} discharged at value I ₀ ,..., Voltage V _n when lead storage battery 10 is discharged at constant discharge current value I ₀ and discharge time t _n , the horizontal axis is time [s], the vertical axis is plotted in a graph of voltage [V].

The open circuit voltage calculating unit 31, the voltage of the lead storage battery 10 in the region any time, by linear regression, the discharge time is calculated voltage V ₀ which lead-acid batteries 10 in the case of zero. For example, as shown in FIG. 7, the open circuit voltage calculation unit 31 linearly regresses the voltage of the lead storage battery 10 in the range from the discharge time 4 [s] to the discharge time 10 [s], The intersection (voltage 2.180 [V]) with the axis (discharge time 0 [s]) is calculated as the voltage V ₀ of the lead storage battery 10 when the discharge time is zero.
The open circuit voltage calculation unit 31 calculates an intercept on the vertical axis (corresponding to the voltage V ₀ of the lead storage battery 10 when the discharge time is zero) using, for example, a relational expression as shown in Expression (8). .
In addition, the open circuit voltage calculation part 31 makes the voltage of the lead storage battery 10 in an arbitrary time range a straight line by combining a quadratic expression, a cubic expression, an exponential function, a logarithmic function, and the like of the discharge time t, for example. Regression or curve regression may be performed.

Next, the open circuit voltage calculation unit 31 calculates the open circuit voltage _Vf in the fully charged state of the lead storage battery 10 using, for example, a relational expression as shown in Expression (9). That is, the open circuit voltage calculation unit 31 determines the open circuit voltage V _f in the fully charged state of the lead storage battery 10 based on the voltage V ₀ , the internal resistance R, and the discharge current I of the lead storage battery 10 when the discharge time is zero. Is calculated.

According to the deterioration diagnosis system 100B according to the present embodiment, the open circuit voltage and the internal resistance in a fully charged state having a large correlation with the discharge capacity of the lead storage battery 10 are calculated, and based on these values, the lead storage battery 10 A discharge capacity that is a deterioration index is calculated. Thereby, since it was difficult to accurately grasp the discharge capacity of the lead storage battery 10, the conventional problem that the degree of deterioration of the lead storage battery 10 cannot be accurately diagnosed is solved, and the degree of deterioration of the lead storage battery 10 is highly accurate. It is possible to realize the deterioration diagnosis system 100B that can be diagnosed quickly.
Especially for lead-acid batteries used as a backup power source, necessary measurements are made in a short time and with a small amount of discharge from the state of float charge or trickle charge, and the discharge capacity (backup time at power failure) Can be calculated. Thereby, it is possible to realize the deterioration diagnosis system 100B that can accurately determine the replacement time of the lead storage battery without impairing the backup function.

<< Fourth Embodiment >>
Next, a deterioration diagnosis system 100C according to the fourth embodiment will be described. Note that the degradation diagnosis system 100C shown in the fourth embodiment is merely an example, and is not limited to this configuration.

The deterioration diagnosis system 100C according to the fourth embodiment is different from the deterioration diagnosis system 100 according to the other embodiments in that the discharge capacity calculation unit 33 includes a discharge electricity quantity, an open circuit voltage data table, an open circuit voltage curve, by using a, open circuit voltage V _f in a fully charged _state, it calculates the open-circuit voltage V _e at the full discharge state, further, in that to calculate the discharge capacity Q.

  For example, as shown in FIG. 8, the open circuit voltage curve is a graph showing the relationship between the discharge electricity quantity and the voltage when the horizontal axis is the discharge electricity quantity [Ah] and the vertical axis is the voltage [V]. . The open circuit voltage curve may be a curve measured in advance for a target product of the lead storage battery 10 or may be measured using a theoretical formula or the like between the sulfate ion concentration and the voltage of the lead storage battery 10. It may be a curved line.

First, the discharge capacity calculation unit 33 calculates a discharge electric quantity Q _f corresponding to the open circuit voltage V _f in the fully charged state based on the open circuit voltage curve, and corresponds to the open circuit voltage V _e in the full discharge state. A discharge electricity quantity _Qe is calculated. The amount of discharge electricity, the open circuit voltage data table, the open circuit voltage curve, and the like are stored in the storage unit 40 in advance.

Next, the discharge capacity calculation unit 33 calculates the discharge capacity Q using, for example, a relational expression as shown in Expression (10). That is, the discharge capacity calculation unit 33 determines the discharge capacity based on the discharge electricity quantity Q _f corresponding to the open circuit voltage V _f in the fully charged state and the discharge electricity quantity Q _e corresponding to the open circuit voltage V _e in the full discharge state. Q is calculated.

According to the degradation diagnosis system 100C according to the present embodiment, the open circuit voltage and the internal resistance in the fully charged state, which have a large correlation with the discharge capacity of the lead storage battery 10, are calculated, and based on these values, the lead storage battery 10 A discharge capacity that is a deterioration index is calculated. Thereby, since it was difficult to accurately grasp the discharge capacity of the lead storage battery 10, the conventional problem that the degree of deterioration of the lead storage battery 10 cannot be accurately diagnosed is solved, and the degree of deterioration of the lead storage battery 10 is highly accurate. It is possible to realize a deterioration diagnosis system 100C that can be diagnosed quickly.
Especially for lead-acid batteries used as a backup power source, necessary measurements are made in a short time and with a small amount of discharge from the state of float charge or trickle charge, and the discharge capacity (backup time at power failure) Can be calculated. Thereby, it is possible to realize a deterioration diagnosis system 100C that can accurately determine the replacement time of the lead storage battery without impairing the backup function.

  The embodiments of the present invention have been specifically described above, but the gist of the present invention is not limited to these descriptions and should be widely interpreted based on the description of the scope of claims. Needless to say, various changes and modifications based on these descriptions are also included in the spirit of the present invention.

  The degradation diagnosis system according to the embodiment of the present disclosure can be used, for example, as a backup power source for an uninterruptible power supply.

10 Lead storage battery 20 Voltage / current control device (control device)
31 Open Circuit Voltage Calculation Unit 32 Internal Resistance Calculation Unit 33 Discharge Capacity Calculation Unit 100 Deterioration Diagnosis System

Claims (7)

A control device for charging the lead storage battery to a predetermined voltage;
An open circuit voltage calculation unit for calculating an open circuit voltage in a fully charged state of the lead storage battery;
An internal resistance calculation unit for calculating the internal resistance of the lead storage battery;
Based on the open circuit voltage and the internal resistance in the fully charged state, a discharge capacity calculation unit that calculates the discharge capacity of the lead storage battery;
A deterioration diagnosis system comprising: The internal resistance calculator is
Based on the AC impedance of the lead storage battery at a single or multiple frequencies, to calculate the internal resistance,
The deterioration diagnosis system according to claim 1. The open circuit voltage calculation unit includes:
Calculating the open circuit voltage in the fully charged state based on the voltage of the lead storage battery and the plurality of predetermined currents when the lead storage battery is discharged with a plurality of predetermined currents for a predetermined time;
The deterioration diagnosis system according to claim 1 or 2, characterized in that The open circuit voltage calculation unit includes:
Calculating the open circuit voltage in the fully charged state based on the voltage of the lead storage battery and the constant predetermined current when the lead storage battery is discharged at a constant predetermined current for a predetermined time;
The deterioration diagnosis system according to claim 1 or 2, characterized in that The discharge capacity calculation unit
Based on the internal resistance and discharge current,
Calculate the open circuit voltage in the fully discharged state of the lead acid battery,
Based on the open circuit voltage in the fully charged state and the open circuit voltage in the fully discharged state,
Calculating the discharge capacity of the lead acid battery;
The deterioration diagnosis system according to any one of claims 1 to 3, wherein the deterioration diagnosis system is characterized in that The discharge capacity calculation unit
Based on the discharge electricity quantity, open circuit voltage curve,
Calculate the open circuit voltage in the fully discharged state of the lead acid battery,
Based on the open circuit voltage in the fully charged state and the open circuit voltage in the fully discharged state,
Calculating the discharge capacity of the lead acid battery;
The deterioration diagnosis system according to any one of claims 1 to 3, wherein the deterioration diagnosis system is characterized in that Charging the lead acid battery to a predetermined voltage;
Calculating an open circuit voltage in a fully charged state of the lead acid battery;
Calculating the internal resistance of the lead acid battery;
Calculating the discharge capacity of the lead-acid battery based on the open circuit voltage and the internal resistance in the fully charged state;
A degradation diagnosis method comprising: