JP2002340959A - Capacitor charge accumulating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reliably and stably detect degradation or failure of each unit capacitor cell in a short time on a plurality of the unit capacitor cells in a serially and parallelly connected state of use. SOLUTION: This capacitor charge accumulating device is provided with a capacitor storage battery 1 in which a plurality of the unit capacitor cells are serially and parallelly connected, a voltage detecting circuit 3 for measuring the terminal voltage of each unit capacitor cell, a control arithmetic circuit 4 for obtaining a terminal voltage variation of each unit capacitor cell in a unit of time from the terminal voltage measured by the voltage detecting circuit and determining the unit capacitor cell of which the terminal voltage variation exceeds a specific value, a voltage limiting circuit 2 for limiting the terminal voltage of each unit capacitor cell, and a display 5 for displaying the results of determination by the control arithmetic circuit. As the terminal voltage variation in a unit of time, a voltage drop in a unit of time, a voltage rise, or the difference between the squares of voltages, the differences from their average values, and ratios to the average values are obtained to display degradation and issue an alarm on failure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a capacitor power storage device in which a plurality of unit capacitor cells are connected in series / parallel.

[0002]

2. Description of the Related Art As a power storage device for a photovoltaic power generation system, a hybrid electric vehicle, or the like, a large-capacity, rapid, large-current chargeable / dischargeable capacitor (electric double layer capacitor) is used instead of a secondary battery. Etc.) came to be used. Since this power storage device has a unit capacitor cell terminal voltage as low as about 2.5 to 3 V, it is practically used by connecting unit capacitor cells in series or in series / parallel.

FIG. 12 is a diagram showing an example of a conventional power storage device in which unit batteries are connected in series, FIG. 13 is a diagram showing the transition of each terminal voltage of a plurality of series-connected unit capacitor cells with charging and discharging, and FIG. FIG. 14 is a diagram showing a difference between each terminal voltage of the unit capacitor cell shown in FIG. 13 and an average terminal voltage.

As a conventional detection method for detecting deterioration or failure of each unit battery cell (unit secondary battery cell / unit capacitor cell) of a power storage device connected in series, for example, JP-A-200
No. 0-123883 has been proposed. This method measures the terminal voltage of each unit battery cell B1 to Bn as shown in FIG. 12, and determines the voltage difference between the unit battery cells, the voltage difference between the terminal voltage of the unit battery cell and the set voltage value, or A failure is determined by determining whether or not the voltage difference between the terminal voltage of the unit battery cell and the average voltage of the terminal voltages of the unit battery cells is within a set voltage range, and a failure alarm or failure alarm is determined. Displaying.

However, in a large-capacity capacitor such as an electric double-layer capacitor, as shown in the charge / discharge example in FIG.
In this example, in order to improve the utilization rate of the capacitor storage battery, the voltage limiting circuit is operated at the maximum rated voltage of each capacitor cell, and the terminal voltage of each unit capacitor cell is made uniform. As described above, since there is a difference in characteristics between the secondary battery and the capacitor that are close to the constant voltage source, there are the following problems.

In the method of comparing the voltage drop as it is, the terminal voltage of the capacitor fluctuates as shown in FIG. 13 due to the remaining energy, so that it is not possible to determine where to set the voltage for judging deterioration or failure. For this reason, the voltage range most usually used (maximum voltage Vm to 1/2 Vm)
It is difficult to judge deterioration or failure in a short time.
Similarly, in the method of comparing the difference between the average terminal voltage and the terminal voltage of each unit capacitor cell, the difference becomes remarkable in a low operating voltage range as shown in the example of FIG. Voltage range (maximum voltage Vm to 1 / 2Vm)
, The difference becomes smaller, and there is a difficulty in setting a set voltage for determining deterioration or failure.

As a screening method for determining a multilayer ceramic capacitor having a deteriorated insulation resistance, a method of applying a DC voltage to the multilayer ceramic capacitor, inverting the polarity, and measuring a leakage current or an insulation resistance after a predetermined time, for example, JP 08-306574 A,
Japanese Patent Application Laid-Open No. 08-227826 has been proposed. When the method implemented in this unit capacitor cell is applied to an apparatus in which a plurality of unit capacitor cells are connected in series and parallel, the measured value is the value of the entire capacitor and the value of each unit capacitor cell is not measured. Of the unit capacitor cell cannot be determined. In order to measure the individual unit capacitor cells, it takes a long time to perform the measurement, or the measurement cannot be performed in a state of being connected in series / parallel, so that a connection change for the measurement is required.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is possible to quickly and reliably determine the deterioration or failure of each unit capacitor cell in a state of use in which a plurality of unit capacitor cells are connected in series and parallel. It is intended to enable good and stable detection.

For this purpose, the present invention provides a capacitor storage battery in which a plurality of unit capacitor cells are connected in series / parallel, a voltage detecting circuit for measuring a terminal voltage of each of the unit capacitor cells, and a terminal voltage measured by the voltage detecting circuit. A control operation circuit for determining a terminal voltage variation per unit time of the unit capacitor cell and determining a unit capacitor cell in which the terminal voltage variation exceeds a predetermined value; and further limiting a terminal voltage of each of the unit capacitor cells. It is characterized by comprising a voltage limiting circuit, and a display for displaying a judgment result by the control arithmetic circuit.

As the terminal voltage fluctuation per unit time, a difference between a voltage drop, a voltage rise or a voltage square per unit time is obtained, and a difference between a voltage drop, a voltage rise or a voltage square per unit time and their average value is calculated. And calculating the ratio of the difference between the voltage drop, voltage rise or voltage square per unit time and their average value, and the control operation circuit limits or stops the charging / discharging current based on the determination result. The terminal voltage fluctuation exceeds a predetermined value, the deterioration or failure is determined for the unit capacitor cell, the deterioration / failure is displayed on the display, and the display is a waveform display of the terminal voltage fluctuation. Is performed.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an embodiment of a capacitor power storage device according to the present invention, wherein 1 is a capacitor storage battery, 2 is a voltage limiting circuit, 3 is a voltage detection circuit, 4 is a control operation circuit, 5 is an alarm failure indicator, Reference numeral 6 denotes a current detector.

In FIG. 1, a capacitor storage battery 1 has a plurality of unit capacitor cells C1,..., Cn connected in series, and a current detector 6 detects a charge / discharge current of the capacitor storage battery 1. . The voltage limiting circuit 2
The parallel monitor VL1 to VLn connected in parallel to each unit capacitor cell C1,..., Cn limits and equalizes the terminal voltage of each unit capacitor cell C1,. 3 measures the terminal voltage of each of the unit capacitor cells C1,..., Cn. The control operation circuit 4 includes a storage circuit, and detects the terminal voltage of each of the unit capacitor cells C1,..., Cn detected by the voltage detection circuit 3 per unit time or at predetermined time intervals, such as a voltage drop / rise, a difference between voltage squares, The magnitude and ratio of the difference from those average values are calculated, and each unit capacitor cell C1,.
.., Cn deterioration or failure is determined, and the alarm failure indicator 5 performs an alarm failure display in accordance with the determination of the deterioration or failure.

[0013] Now, t if _i the terminal voltage of the unit capacitor cells and Vt _i during the control arithmetic circuit 4 in, for example, t terminal voltage Vt ₁ o'clock ₁ and t ₂ at the terminal voltage Vt ₂
From the voltage drop / rise (Vt ₁ -Vt) per unit time
_{2) / (t 2 -t 1} ), the voltage squared difference (Vt ₁ ² -Vt
_{When 2} ² ) / (t ₂ −t ₁ ) exceeds a predetermined value, or when an average value thereof is obtained and a difference from the average value exceeds a predetermined value, the average value is calculated. If the degree of difference exceeds a predetermined value, it is determined that the battery has deteriorated or failed. In a short time after charging / discharging and in a voltage range which is most frequently used at a normal time, in a range of a maximum voltage Vm to 1 / 2Vm (for example, Vm: 3V),
In a deteriorated unit capacitor cell, the difference between the voltage drop per unit time and the difference between the voltage squares in proportion to the leakage current becomes remarkable. The measured value of the voltage range that is used most often for a short time and at normal times is used as a criterion for determination. For example, the terminal voltage drop per unit time is mainly proportional to the leakage current, and the difference in voltage square per unit time is mainly proportional to the difference in stored energy.

In a large-capacity capacitor such as an electric double layer capacitor, the leakage current reduces the stored energy and stops the terminal voltage when charging and discharging are stopped. For products of the same standard, the capacitance and equivalent series resistance have relatively small variations, but the leakage current has relatively large variations.
This causes a variation in terminal voltage between the unit capacitor cells. The increase in the leakage current, the equivalent series resistance, and the equivalent internal resistance also includes information on deterioration and failure of the unit capacitor cell. Therefore, in the capacitor power storage device, it is possible to indirectly measure the leakage current and the equivalent internal resistance of each unit capacitor cell, thereby making it possible to indicate a deterioration alarm or display a failure. Conventionally, in a capacitor power storage device in which a plurality of unit capacitor cells are connected in series / parallel, there is no device that indirectly measures these and measures deterioration or failure.

Next, regarding the terminal voltage fluctuation per unit time, the difference between the voltage drop, the voltage rise or the voltage square per unit time is used as a criterion for judgment, and the voltage drop, the voltage rise or the voltage square per unit time is further determined. The difference between the difference and their average value, the voltage drop per unit time, the voltage rise or the difference between the voltage squared and the ratio of their average value to the determination criteria,
Each case of performing the comparison judgment with the predetermined value will be described in detail.

FIG. 2 is a diagram showing an example of the voltage drop of each unit capacitor, FIG. 3 is a diagram for explaining the difference between the voltage drop shown in FIG. 2 and the average value, and FIG. 4 is a diagram of the voltage drop shown in FIG. It is a figure for explaining a comparative example (%) with an average value.

Regarding the terminal voltage fluctuation per unit time,
When the determination is made based on the voltage drop per unit time, the charge stop is determined by the current detector 6 or the charge / discharge command,
After the charging is stopped, the terminal voltage of each of the unit capacitor cells C1 to Cn is measured by the voltage detection circuit 2 every predetermined unit time. The measured terminal voltages of the unit capacitor cells C1 to Cn are stored in the storage circuit of the control operation circuit 4.

Next, from the terminal voltage stored in the storage circuit, the control operation circuit 4 calculates a terminal voltage drop per unit time of the unit capacitor cell for determining the deterioration or failure state. FIG. 2 shows an example of calculating the terminal voltage drop of each of the unit capacitor cells C1 to Cn per unit time after charging is stopped between T1 and T2 in FIG.

The control arithmetic circuit 4 determines whether or not the calculated voltage drop per unit time exceeds a predetermined value (deterioration determination line).
If the value exceeds a predetermined value, a warning of deterioration or a display of a failure is displayed on the alarm failure indicator 5.

Further, when the terminal voltage variation per unit time is determined based on the difference between the voltage drop per unit time and the average value, the control arithmetic circuit 4 calculates the average value of the voltage drop per unit time. , The difference between the average value of the voltage drop and the voltage drop per unit time of the unit capacitor cell for determining the deterioration or failure state is calculated. FIG. 3 shows an example of calculating the difference from the average value from the voltage drop in FIG.
It is.

The control arithmetic circuit 4 determines whether or not the difference from the average value exceeds a predetermined value (deterioration determination line). If the difference exceeds the predetermined value, a warning of deterioration or a display of a failure is displayed. This is performed by the alarm failure indicator 5.

When the terminal voltage fluctuation per unit time is determined based on the ratio between the voltage drop per unit time and the average thereof, the deterioration or failure state is determined per unit time of the unit capacitor cell. Divide the voltage drop by the average value of the voltage drop per unit time. FIG. 4 shows an example in which the average value is calculated from the voltage drops in FIG. 2 and each voltage drop is shown in percentage. The control arithmetic circuit 4 determines whether or not the divided value exceeds a predetermined value (deterioration determination line). If the value exceeds the predetermined value, a warning of deterioration or display of a failure is displayed on an alarm failure indicator 5. Do with.

FIG. 5 is a diagram showing an example of a difference between voltage squares per unit time of each unit capacitor. FIG. 6 is a diagram for explaining a difference from an average value of a difference of voltage squares per unit time shown in FIG. FIG. 7 is a diagram for explaining a comparative example (%) with the average value of the difference between the voltage squares per unit time shown in FIG.

Regarding the terminal voltage fluctuation per unit time,
When the determination is made based on the difference of the squared voltage per unit time, first, the charge stop is determined by the current detector 6, and after the charge stop, the terminal voltages of the unit capacitor cells C <b> 1 to Cn are determined by the voltage detection circuit 2. Measure every unit time. The measured terminal voltages of the unit capacitor cells C1 to Cn are stored in the storage circuit of the control operation circuit 4.

The control operation circuit 4 calculates a difference of a voltage square per unit time of the unit capacitor cell for judging the deterioration or the failure state from the terminal voltage stored in the storage circuit. FIG. 5 shows an example of calculating the difference between the squares of the voltages of the unit capacitor cells C1 to Cn per unit time after the charging is stopped between T1 and T2 in FIG.

The control arithmetic circuit 4 determines whether or not the obtained difference in voltage squared per unit time exceeds a predetermined value (deterioration determination line). The failure is displayed on the alarm failure indicator 5.

Further, when the difference of the voltage square per unit time is determined by the difference from the average value with respect to the terminal voltage fluctuation per unit time, the control arithmetic circuit 4 calculates the average value of the difference of the voltage square per unit time. Is calculated, and the average value of the difference of the voltage square per unit time is compared with the difference of the voltage square per unit time of the unit capacitor cell for determining the deterioration or the failure state, and the difference is calculated. FIG. 6 shows an example of the calculation. The control arithmetic circuit 4 determines whether or not the difference exceeds a predetermined value (deterioration determination line). If the difference exceeds the predetermined value, a warning of deterioration or a failure is displayed on the alarm failure indicator 5. .

In the case where the difference between the voltage squares per unit time and the difference between the voltage squares per unit time and the average value are determined with respect to the terminal voltage fluctuation per unit time, the deterioration or failure state is determined. Divide the voltage squared difference by the average of the voltage squared differences per unit time. FIG. 7 shows an example in which the divided value is shown as a percentage.

The control arithmetic circuit 4 determines whether or not the divided value exceeds a predetermined value. If the divided value exceeds a predetermined value (deterioration determination line), a warning of deterioration or a display of a failure is displayed as an alarm failure display. This is performed in the vessel 5.

FIG. 8 is a diagram showing an example of a voltage rise of each unit capacitor, FIG. 9 is a diagram for explaining a difference from the average value of the voltage rise shown in FIG. 8, and FIG. It is a figure for explaining a comparative example (%) with an average value.

Regarding the terminal voltage fluctuation per unit time,
When the determination is made based on the voltage rise of each unit capacitor per unit time, first, the discharge stop is determined by the current detector 6, and after the discharge stop, the terminal voltages of the unit capacitor cells C1 to Cn are determined by the voltage detection circuit 2. The measurement is performed every predetermined unit time. The measured terminal voltages of the unit capacitor cells C1 to Cn are stored in the storage circuit of the control operation circuit 4.

The control operation circuit 4 calculates the terminal voltage rise per unit time of the unit capacitor cell for determining the deterioration or failure state from the terminal voltage stored in the storage circuit. FIG. 8 shows an example of calculating the terminal voltage rise per unit time in the period from T2 to T3 in FIG.

The control operation circuit 4 determines whether the calculated voltage rise per unit time exceeds a predetermined value (deterioration determination line).
If the value exceeds a predetermined value, a warning of deterioration or a display of a failure is displayed on the alarm failure indicator 5.

Further, when the terminal voltage fluctuation per unit time is determined based on the difference from the average value of the voltage rise per unit time, the control arithmetic circuit 4 calculates the average value of the voltage rise per unit time. Further, a difference between the average value and a voltage rise per unit time of the unit capacitor cell for determining deterioration or failure is calculated. FIG. 9 shows an example showing the calculated difference.

The control arithmetic circuit 4 determines whether or not the difference between the average value of the voltage rise and the voltage rise exceeds a predetermined value (deterioration determination line). If the difference exceeds the predetermined value, a deterioration alarm is issued. Alternatively, the failure is displayed on the alarm failure indicator 5.

When the terminal voltage fluctuation per unit time is determined based on the ratio of the voltage increase per unit time to the average value, the control operation circuit 4 determines whether the unit capacitor cell is deteriorated or faulty. Is divided by the average value of the voltage rise per unit time. FIG. 10 shows an example in which the divided value is shown as a percentage.

The control operation circuit 4 determines whether or not the divided value exceeds a predetermined value (deterioration determination line). If the value exceeds the predetermined value, a warning of deterioration or a display of failure is displayed as an alarm failure display. This is performed in the vessel 5.

FIG. 11 is a diagram showing another embodiment of the capacitor power storage device according to the present invention, and 7 is a charge / discharge current limiting circuit.

In FIG. 11, the charge / discharge current limiting circuit 7
Indicates a warning of deterioration or an indication of failure of the unit capacitor cells C1 to Cn constituting the capacitor storage battery 1,
At the same time, the charge / discharge current is limited or stopped by a command from the control operation circuit 4.

It should be noted that the present invention is not limited to the above embodiment, and various modifications are possible. For example, in the above-described embodiment, the terminal voltage fluctuation per unit time is calculated and stored in the storage circuit, and the determination is made to perform the deterioration warning or the failure display. The value stored in the circuit may be displayed as a waveform on the alarm failure indicator 5.

[0041]

As is apparent from the above description, according to the present invention, after the charging is stopped, the terminal voltage drop per unit time of the unit capacitor cell is calculated, and the calculated voltage drop per unit time is a predetermined value. Since it is determined whether or not the value exceeds the value, a warning of deterioration due to a leakage current or the like of the unit capacitor cell or a display of a failure can be displayed.

After the charging is stopped, the average value of the voltage drop per unit time of the unit capacitor cell is calculated, and the average value of the voltage drop is compared with the voltage drop per unit time of the unit capacitor cell for judging deterioration or failure. And, furthermore,
Since the voltage drop per unit time of the unit capacitor cell for which deterioration or failure is judged is divided by the average value of the voltage drop per unit time, it can be stably performed from a relatively short time after charging is stopped to a long time. Deterioration or failure of the unit capacitor cell can be determined. In addition, even when the terminal voltage is relatively high, deterioration and failure can be predicted and determined.

Similarly, after the charging is stopped, the difference of the voltage square per unit time of the unit capacitor cell is calculated, and it is determined whether or not the calculated voltage square difference exceeds a predetermined value. A warning of deterioration due to leakage current or an indication of failure can be displayed, an average value of a difference between voltage squares per unit time of a unit capacitor cell is calculated, and a unit of the unit capacitor cell to determine the average value and the deterioration or failure state By comparing the difference in voltage squared per time, the difference in voltage squared per unit time of the unit capacitor cell for determining the deterioration or failure state is divided by the average value of the difference in voltage squared per unit time. In addition, the deterioration or failure of the unit capacitor cell can be determined stably from a relatively short time to a long time after the charging is stopped.

After the discharge is stopped, the terminal voltage of the unit capacitor cell is measured, and the terminal voltage rise per unit time of the unit capacitor cell for determining the deterioration or failure state is calculated.
Since it is determined whether or not the calculated voltage rise per unit time exceeds a predetermined value, it is possible to warn of a deterioration due to an increase in the internal resistance of the unit capacitor cell or to display a failure, and to display the voltage rise per unit time. Calculate the average,
By comparing the average value and the voltage rise per unit time of the unit capacitor cell for determining the deterioration or failure state, the voltage rise per unit time for the unit capacitor cell for determining the deterioration or failure is further increased. , The deterioration or failure of the unit capacitor cell can be determined stably from a relatively short time to a long time after the discharge is stopped.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an embodiment of a capacitor power storage device according to the present invention.

FIG. 2 is a diagram illustrating an example of a voltage drop of each unit capacitor.

FIG. 3 is a diagram for explaining a difference from an average value of a voltage drop shown in FIG. 2;

4 is a diagram for explaining a comparative example (%) with the average value of the voltage drop shown in FIG. 2;

FIG. 5 is a diagram illustrating an example of a difference between voltage squares per unit time of each unit capacitor.

FIG. 6 is a diagram for explaining a difference from an average value of a difference between voltage squares per unit time shown in FIG. 5;

FIG. 7 is a diagram for explaining a comparative example (%) with an average value of a difference between voltage squares per unit time shown in FIG. 5;

FIG. 8 is a diagram illustrating an example of a voltage drop of each unit capacitor.

FIG. 9 is a diagram for explaining a difference from the average value of the voltage rise shown in FIG. 8;

FIG. 10 is a diagram for explaining a comparative example (%) with the average value of the voltage rise shown in FIG. 8;

FIG. 11 is a diagram showing another embodiment of the capacitor power storage device according to the present invention.

FIG. 12 is a diagram illustrating an example of a conventional power storage device in which unit batteries are connected in series.

FIG. 13 is a diagram showing a transition accompanying charge / discharge of each terminal voltage of a plurality of unit capacitor cells connected in series.

14 is a diagram illustrating a difference between a terminal voltage of the unit capacitor cell illustrated in FIG. 13 and an average terminal voltage.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 capacitor storage battery 2 voltage limit circuit 3 voltage detection circuit 4 control operation circuit 5 alarm failure indicator 6
Current detector, 7 ... Charge / discharge current limiting circuit

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 2G036 AA24 AA27 BA12 BB02 BB08 CA08 5H410 BB00 CC02 DD02 EB01 EB27 EB37 EB39 FF03 FF09 FF18 FF25 FF29 GG07 HH05 LL12 LL13 LL18 LL19 LL20

Claims (8)

[Claims] 1. A capacitor storage battery in which a plurality of unit capacitor cells are connected in series / parallel, a voltage detection circuit for measuring a terminal voltage of each unit capacitor cell, and a voltage detection circuit for each unit capacitor cell based on the terminal voltage measured by the voltage detection circuit. A capacitor arithmetic operation circuit for determining a terminal voltage variation per unit time and determining a unit capacitor cell in which the terminal voltage variation exceeds a predetermined value. 2. A capacitor storage battery in which a plurality of unit capacitor cells are connected in series / parallel, a voltage limiting circuit for limiting a terminal voltage of each of the unit capacitor cells, and a voltage detecting circuit for measuring a terminal voltage of each of the unit capacitor cells. A control operation circuit for determining a terminal voltage change per unit time of each unit capacitor cell from a terminal voltage measured by the voltage detection circuit, and determining a unit capacitor cell in which the terminal voltage change exceeds a predetermined value; A display for displaying a determination result by the circuit. 3. The capacitor power storage device according to claim 1, wherein a difference between a voltage drop, a voltage rise, and a voltage square per unit time is obtained as the terminal voltage fluctuation per unit time. 4. The method according to claim 1, wherein a difference between a voltage drop, a voltage rise or a voltage squared difference per unit time and an average thereof is obtained as the terminal voltage fluctuation per unit time. Capacitor storage device. 5. The method according to claim 1, wherein a ratio of a difference between a voltage drop, a voltage rise or a voltage square per unit time and an average thereof is obtained as the terminal voltage fluctuation per unit time. Capacitor storage device. 6. The capacitor power storage device according to claim 1, wherein the control operation circuit controls the limitation or stop of the charging / discharging current based on the determination result. 7. The control operation circuit according to claim 1, wherein the control unit determines deterioration or failure of the unit capacitor cell in which the terminal voltage fluctuation exceeds a predetermined value, and performs deterioration / failure indication on the display. 3. The capacitor power storage device according to 2. 8. The capacitor power storage device according to claim 2, wherein the display performs a waveform display of the terminal voltage fluctuation.