JP2013242197A - Electrostatic capacitance measurement system and method and degradation state estimation system and method of capacitor cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately measure the effective electrostatic capacitance of a capacitor cell even when the electrostatic capacitance of the capacitor cell is measured at a given voltage.SOLUTION: A system includes voltage measurement means for detecting cell voltages of a plurality of capacitor cells C1 to Cn, voltage adjustment means for decreasing or increasing the voltages of the capacitors C1 to Cn, and an arithmetic operation device 16 for controlling the voltage measurement means. The arithmetic operation device 16 determines, based on the cell voltages of the capacitor cells C1 to Cn measured by the voltage measurement means, a measurement start voltage and a measurement end voltage, measures voltage measurement time for dropping of the cell voltages of the capacitor cells C1 to Cn from the measurement start voltage to the measurement end voltage, calculates the electrostatic capacitances of the capacitor cells C1 to Cn on the basis of the voltage measurement time, and corrects the electrostatic capacitances by correction values according to the capacitor cells C1 to Cn to calculate effective electrostatic capacitances.

Description

  The present invention relates to a capacitance measuring system and a capacitance measuring method for measuring an effective capacitance of a capacitor cell in a state where the power storage device is not charged / discharged in a power storage device including a plurality of capacitor cells, and The present invention relates to a degradation state estimation system and degradation state estimation method for a capacitor cell that estimates a degradation state of the capacitor cell from the measured effective capacitance of the capacitor cell.

  It is known that the characteristics of a capacitor cell such as an electric double layer capacitor or a lithium ion capacitor change due to deterioration over time, the capacitance of the capacitor cell gradually decreases, and the internal resistance gradually increases.

For this reason, a power storage device including a plurality of capacitor cells has a reduced power storage capacity as the capacitor cells age.
Such a deterioration state of the capacitor cell is determined by detecting the charging current or the discharging current during charging / discharging of the power storage device, and measuring the static voltage of each capacitor cell measured based on the change over time of the charging current or discharging current and the cell voltage. It is common to estimate from the electric capacity.

  As described above, when the method of estimating the capacitance of the capacitor cell using the charging current or the discharging current is used, the deterioration state of the capacitor cell cannot be estimated unless the power storage device is in a charging / discharging state. In order to estimate the deterioration state of the capacitor cell, a measuring device for measuring the charge / discharge current is required.

  For this reason, for example, in Patent Document 1, as shown in FIG. 4, the voltage detection means 104 for detecting the cell voltage of the capacitor cell 102 connected in parallel to the capacitor cell 102 and the capacitor cell 102 are connected in parallel. There has been proposed a capacitor life determination device 100 provided with an inspection circuit 106 connected to the capacitor.

In the inspection circuit 106, a discharge switch 108 and a short-circuit switch 110 to which a discharge resistor r is connected in parallel are connected in series.
In this life determination apparatus 100, when the capacitor cell 102 is fully charged, the discharge switch 108 is turned on and the short-circuit switch 110 is turned off, thereby forming a closed circuit of the capacitor cell 102 and the discharge resistor r. Then, the discharge of the capacitor cell 102 is started.

  Then, by measuring the constant resistance discharge time from the fully charged state to the set voltage, based on the initial constant resistance discharge time when the capacitor is not deteriorated and the time constant resistance discharge time when the capacitor is deteriorated The determination of the deterioration state of the electric double layer capacitor is disclosed.

JP 2008-27946 A

  By the way, it is known that the capacitance of the capacitor cell has voltage dependency. For example, as shown in FIG. 5, the capacitance when the cell voltage is 3.8V and the capacitance of 3.0V The capacitance at this time is very different. However, in a power storage device including a conventional capacitor cell, the deterioration state of the capacitor cell is determined without considering the voltage dependency of the capacitance of the capacitor cell.

  For this reason, when determining the deterioration state of a capacitor cell at an arbitrary voltage, it may be determined that a capacitor cell that has not been deteriorated is deteriorated, and the deterioration state of the capacitor cell is determined. Therefore, it was necessary to always measure the capacitance of the capacitor cell with a predetermined voltage.

  In the present invention, when measuring the capacitance of the capacitor cell, the effective capacitance is calculated by correcting the capacitance of the capacitor cell measured using a correction value measured in advance. And providing a capacitance measuring system and a capacitance measuring method capable of accurately measuring the effective capacitance of the capacitor cell even when the capacitance of the capacitor cell at an arbitrary voltage is measured. Objective.

  In the present invention, a capacitance measuring system and a capacitance measuring method for measuring the effective capacitance of a capacitor cell using an equalization control circuit without providing a dedicated circuit for measuring the effective capacitance The purpose is to provide.

  A further object of the present invention is to provide a degradation state estimation system and degradation state estimation method for a capacitor cell that estimates the degradation state of the capacitor cell from the measured effective capacitance of the capacitor cell.

The present invention has been invented to achieve the above-described object, and the capacitance measurement system of the present invention provides an effective capacitance of a capacitor cell in a power storage device including a plurality of capacitor cells. A capacitance measuring system for measuring,
Voltage measuring means for detecting a cell voltage of each of the plurality of capacitor cells;
Voltage adjusting means for decreasing or increasing the cell voltage of the plurality of capacitor cells;
An arithmetic processing unit for controlling the voltage measuring means,
The arithmetic processing unit is
Based on the cell voltage of the plurality of capacitor cells measured by the voltage measuring means, determine a measurement start voltage and a measurement end voltage,
Measuring the cell voltage of the capacitor cell by the voltage measuring means, and measuring the voltage measurement time during which the cell voltage of the capacitor cell drops or rises from the measurement start voltage to the measurement end voltage by the voltage adjusting means,
Based on the voltage measurement time, the capacitance of the capacitor cell is calculated, and the capacitance is corrected by a correction value corresponding to the capacitor cell to calculate an effective capacitance. It is characterized by being.

Further, the capacitance measuring method of the capacitor cell of the present invention is a capacitance measuring method for measuring the effective capacitance of the capacitor cell in a power storage device including a plurality of capacitor cells,
Measuring cell voltages of the plurality of capacitor cells;
Determining a measurement start voltage and a measurement end voltage based on the measured cell voltages of the plurality of capacitor cells;
Measuring a voltage measurement time during which the cell voltage of the capacitor cell drops or rises from the measurement start voltage to the measurement end voltage by voltage adjusting means;
Calculating a capacitance of the capacitor cell based on the voltage measurement time;
And correcting the capacitance with a correction value corresponding to the capacitor cell to calculate an effective capacitance.

  By configuring in this way, it is possible to accurately measure the effective capacitance by adding a correction value to the capacitance. For example, it is possible to more accurately perform cell deterioration detection and the like. The life of the device can be extended.

  Further, for example, since the capacitance of the capacitor cell can be measured using the equalization control circuit provided in the power storage device, the capacitance of the capacitor cell can be measured without providing a dedicated circuit. it can.

  In the present invention, the “effective capacitance” is a capacitance when the voltage dependence of the capacitance of the capacitor cell is not considered, and the “effective capacitance” of the capacitor cell that is not deteriorated is Rated capacity. That is, as the capacitor cell deteriorates, the “effective capacitance” of the capacitor cell decreases.

Further, the capacitance measuring system of the present invention is characterized in that the arithmetic processing unit is configured to calculate the capacitance of the capacitor cell based on the following formula 1.

The capacitance measuring method of the present invention is characterized in that the capacitance of the capacitor cell is calculated based on the following formula 1.

In the capacitance measuring system of the present invention, the voltage adjusting unit is a charge consuming unit for consuming the charges of the plurality of capacitor cells,
The arithmetic processing unit is
In order to consume the charge of the capacitor cell, control is performed so that a current flows from the capacitor cell to the charge consuming means,
The cell voltage of the capacitor cell is measured by the voltage measuring means, and the voltage measurement time for the cell voltage of the capacitor cell to drop from the measurement start voltage to the measurement end voltage is measured. Features.

The capacitance measuring method of the present invention further includes a step of consuming charges of the plurality of capacitor cells,
The voltage measurement time during which the cell voltage of the capacitor cell drops from the measurement start voltage to the measurement end voltage is measured.

In the capacitance measuring system according to the present invention, the charge consuming means is an equalization control resistor connected in parallel to the capacitor cell, and the voltage measuring means is a cell voltage detection circuit. ,
An equalization control switch connected in parallel to the plurality of capacitor cells;
An equalization cell selection circuit for controlling the equalization control switch, and
The equalization control switch connected in parallel to the capacitor cell so that the arithmetic processing unit causes a current to flow from the capacitor cell to the equalization control resistor so as to consume the charge of the capacitor cell. The equalization cell selection circuit is controlled so as to be in the on state.

The capacitance measuring system of the present invention is characterized in that the capacitor cell is a lithium ion capacitor.
The capacitance measuring method of the present invention is characterized in that the capacitor cell is a lithium ion capacitor.

Moreover, the degradation state estimation system of the capacitor cell of the present invention includes any one of the capacitance measurement systems described above,
The arithmetic processing unit is
Calculate the capacitance ratio between the effective capacitance of the capacitor cell calculated based on the voltage measurement time and the rated capacity of the capacitor cell;
The deterioration state of the capacitor cell is estimated based on the capacity ratio.

Further, the degradation state estimation method of the capacitor cell of the present invention includes a step of measuring the capacitance of the capacitor cell by any one of the capacitance measurement methods described above,
Calculating a capacitance ratio between the effective capacitance of the capacitor cell and the rated capacity of the capacitor cell;
And a step of estimating a deterioration state of the capacitor cell based on the capacity ratio.

  According to the present invention, even when the capacitance of the capacitor cell at an arbitrary voltage is measured, the effective capacitance of the capacitor cell can be accurately measured by adding a correction value to the capacitance, For example, since cell deterioration can be detected more accurately, the deterioration state of the power storage device can be accurately determined. Furthermore, since the deterioration of the cell can be accurately detected, the life of the power storage device can be extended.

  In addition, it is configured to measure the capacitance of the capacitor cell using the equalization control circuit provided in the power storage device and estimate the deterioration state of the capacitor cell. There is no need to provide a circuit.

  Furthermore, according to the present invention, the deterioration state of the capacitor cell can be estimated from the measured effective capacitance of the capacitor cell, and it is determined that the capacitor cell that has not deteriorated is deteriorated. There is no.

FIG. 1 is a circuit configuration diagram of a power storage device including the degradation state estimation system of the present invention. FIG. 2 is a flowchart showing a flow of measuring the effective capacitance of the capacitor cells C _{1 to} C _n using the capacitance measuring circuit 11 in the power storage device 10 of FIG. FIG. 3 is a circuit configuration diagram of another embodiment of a power storage device including the degradation state estimation system of the present invention. FIG. 4 is a circuit configuration diagram of a conventional capacitor life determination apparatus. FIG. 5 is a graph for explaining the voltage dependency of the capacitance of a general capacitor cell.

  Hereinafter, embodiments (examples) of the present invention will be described in more detail based on the drawings. In addition, although embodiment of a present Example is shown below, this invention is not limited to this embodiment. The embodiment used in the present invention can be suitably used for capacitor cells such as lithium ion capacitors and electric double layer capacitors.

FIG. 1 is a circuit configuration diagram of a power storage device including the degradation state estimation system of the present invention.
The power storage device 10 of this embodiment includes capacitor cells C _{1 to} C _n and a capacitance measurement circuit 11.

Capacitance measurement circuitry 11 includes a measurement IC13 containing the charge dissipation means in order to consume the voltage measuring means and the capacitor cells C ₁ -C _n charge for measuring cell voltages of the capacitor cells C ₁ -C _n The arithmetic processing unit 16 for controlling the measurement IC 13 and the power supply circuit 18 for supplying electric power for operating the arithmetic processing unit 16 from the capacitor cells C _{1 to} C _n .

  The arithmetic processing unit 16 is constituted by a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory) in which an arithmetic processing program is stored, and the like. It is configured.

  The arithmetic processing unit 16 and the measurement IC 13 transmit, for example, a control command from the arithmetic processing unit 16 to the measurement IC 13, or transmit a cell voltage value, a current value, or the like from the measurement IC 13 to the arithmetic processing unit 16. For example, the communication means 20 for two-way communication is provided.

On the other hand, the power storage unit 22 of the power storage device 10 is configured by connecting _n capacitor cells C _{1 to} C _n made of lithium ion capacitors in series.
Both ends of the power storage unit 22 are connected to the power supply circuit 18, and are configured to operate the arithmetic processing device 16 using the power of the power storage unit 22. That is, the power storage device 10 including the capacitance measurement circuit 11 of the present embodiment can measure the capacitances of the capacitor cells C _{1 to} C _n using the power of the power storage device 10 itself.

In this embodiment, in order to measure the capacitances of the capacitor cells C _{1 to} C _n using the power of the power storage device 10 itself, a power supply circuit that operates the arithmetic processing device 16 using the power of the power storage unit 22. 18, the power for operating the arithmetic processing device 16 without the power supply circuit 18 when the arithmetic processing device 16 is configured to operate using electric power from the outside of the power storage device 10. Can be directly supplied to the arithmetic processing unit 16 from the outside.

The operation flow of the capacitance measuring circuit 11 when measuring the capacitance of the capacitor cell of this embodiment will be described below with reference to the flowchart shown in FIG.
FIG. 2 is a flowchart showing a flow of measuring the effective capacitance of the capacitor cells C _{1 to} C _n using the capacitance measuring circuit 11 in the power storage device 10 of FIG.

As shown in FIG. 2, when a command is transmitted from the arithmetic processing unit 16 to the measurement IC 13 to measure the effective capacitances of the capacitor cells C _{1 to} C _n (S10), first, voltage measurement means Using (measurement IC 13), the cell voltages of the capacitor cells C _{1 to} C _n are sequentially measured (S20).

It is determined whether or not the cell voltage has been measured for all the capacitor cells C _{1 to} C _n (S25). If there is a capacitor cell whose cell voltage has not been measured, the cell voltage of the next capacitor cell is measured. The The measured cell voltage value is stored in the RAM of the arithmetic processing unit 16 in association with the capacitor cells C _{1 to} C _n .

Next, from the cell voltage values of the capacitor cells C _{1 to} C _n stored in the RAM of the arithmetic processing device 16, the arithmetic processing device 16 causes the measurement start voltage Vds and the measurement end voltage of each of the capacitor cells C _{1 to} C _n to be measured. Vde is determined (S30).

Measurement starting voltage Vds and a measurement end voltage Vde is a value lower than the cell voltage value of the capacitor cells C ₁ -C _n, particularly limited as long as the voltage value capacitor cells C ₁ -C _n is not over-discharged Never happen.

Also, measurement start voltage Vds and a measurement end voltage Vde may can either be determined individually for the capacitor cell C ₁ -C _n, single voltage value based on the capacitor cell C ₁ -C _n respective cell voltage values, For example, the minimum value of the cell voltages of the capacitor cells C _{1 to} C _n can be set.

  Further, a value lower than the measurement start voltage Vds is selected as the measurement end voltage Vde, and can be set to a value lower by 0.1 V than the measurement start voltage Vds, for example.

Next, the charge of the capacitor cell C _m (m is a cell number and a value between 1 and n (n ≧ 2)) for measuring the capacitance is consumed by the charge consuming means (measurement IC 13) ( S40).
In this state, the cell voltage of the capacitor cells C _m measured by the voltage measuring means (measurement IC 13), whether or not the cell voltage reaches the measurement start voltage Vds is determined (S50).

The cell voltage of the capacitor cells C _m is, if it does not reach the measurement start voltage Vds, when the measured cell voltage is continued (S55), reaching the capacitor cell C cell voltage measurement start voltage _m Vds A timer for measuring the time required for the voltage to drop to the measurement end voltage Vde (hereinafter referred to as “voltage measurement time”) is activated (S60).

  For example, a timer or a counter provided in the arithmetic processing unit 16 or the measurement IC 13 can be used as the timer. When the counter is used, the timer is based on the difference between the counter at the end of measurement and the counter at the start of measurement. Thus, the measurement time can be calculated.

  Even during the operation of the timer, the cell voltage of the capacitor cell Cm is measured using the voltage measuring means (measuring IC 13) (S70), and it is determined whether or not the cell voltage has reached the measurement end voltage Vde (S75). ).

The cell voltage of the capacitor cells C _m is, if it does not reach the end of the measurement voltage Vde is the measurement of the cell voltage is continued, when reached, stops the timer (S80).
Thus, the voltage measurement time measured by the timer is stored in the RAM of the arithmetic processing unit 16 in association with the capacitor cells C _{1 to} C _n .

It is determined whether or not the voltage measurement time has been measured for all the capacitor cells C _{1 to} C _n (S90). If there is a capacitor cell for which the voltage measurement time has not been measured, the process returns to S40, and the next capacitor The cell voltage measurement time is measured.

If the voltage measurement time for all the capacitor cells C ₁ -C _n is measured on the basis of the voltage measurement time stored in the RAM of the arithmetic processing unit 16 capacitor cells C ₁ -C _n, the capacitor cells C ₁ the effective capacitance is calculated in ~C _n (S100).

The effective capacitances of the capacitor cells C _{1 to} C _n can be calculated by, for example, the arithmetic processing unit 16 as in the following Expression 1.

Effective capacitance of the thus calculated capacitor cells C ₁ -C _n is stored in RAM of the arithmetic processing unit 16 in association with the capacitor cells C ₁ -C _n, the effective electrostatic capacitor cells C ₁ -C _n The calculation of the electric capacity is completed (S110).

Then, the arithmetic processing unit 16, and the effective capacitance of the capacitor cells C ₁ -C _n stored in a RAM, calculated volume ratio of the rated capacity of the capacitor cells C ₁ -C _n, respectively, the capacity ratio is predetermined If it is smaller than the deterioration ratio, it is determined that the capacitor cell is deteriorated.

The correction value C _v, for example, by using the capacitor cells C ₁ -C for the same tests as _n capacitor cells C _t used in power storage device 10, based on the S10～S110, a plurality of discharge starting voltage Vds By measuring the discharge time t _{m in} combination with the discharge end voltage Vde, the difference between the capacitance obtained from the following equation 2 and the rated capacity of the test capacitor cell C _t can be set as the correction value C _v. it can.

The correction value C _v can be as a database associated with the voltage value, stored in the RAM of the arithmetic processing unit 16.
In the present embodiment, by using a charge dissipation means, the cell voltage of the capacitor cells C _m is, although measures the voltage measurement time from the measurement start voltage Vds until drops to end of the measurement voltage Vde, for example, charge by using a means, the cell voltage of the capacitor cells C _m may also be measured voltage measurement time from the measurement start voltage Vds until rising to the end of the measurement voltage Vde.

In this case, the measurement start voltage Vds and a measurement end voltage Vde is a value higher than the cell voltage value of the capacitor cells C ₁ -C _n, be the voltage value capacitor cells C ₁ -C _n is not overcharged Can do.

Also, measurement start voltage Vds and a measurement end voltage Vde may can either be determined individually for the capacitor cell C ₁ -C _n, single voltage value based on the capacitor cell C ₁ -C _n respective cell voltage values, For example, the maximum cell voltage of the capacitor cells C _{1 to} C _n can be set.

In addition, a value higher than the measurement start voltage Vds is selected as the measurement end voltage Vde, and can be set to a value higher by 0.1 V than the measurement start voltage Vds, for example.
Thus, in the present invention, the voltage measuring means such as the charge consuming means and the charging means is used to measure the voltage measurement time until the cell voltage of the capacitor cell reaches the measurement end voltage Vde from the measurement start voltage Vds, Based on this voltage measurement time, the capacitance of the capacitor cell can be calculated.

FIG. 3 is a circuit configuration diagram of another embodiment of a power storage device including the degradation state estimation system of the present invention.
The power storage device 10 of this embodiment includes capacitor cells C _{1 to} C _n and an equalization control circuit 12.

  The power storage device 10 provided with the degradation state estimation system of this embodiment has basically the same configuration as the power storage device 10 shown in FIGS. 1 and 2, and the same components are denoted by the same reference numerals. Detailed description thereof is omitted.

The equalization control circuit 12 includes equalization control resistors R _{1 to} R _n (charge consuming means) and FETs (Field Effect Transistors) connected in parallel to the capacitor cells C _{1 to} C _n , respectively. parallel and equalization control switch S ₁ to S _n, with respect to the capacitor cells C ₁ -C cell voltage detecting circuit (voltage measurement unit) for the cell voltage detecting each of _n and a capacitor cell for the equalization control comprising An equalization IC 14 including an equalization cell selection circuit for controlling an equalization control switch connected to the circuit, an arithmetic processing unit 16 for controlling the equalization IC 14, and arithmetic processing from the capacitor cells C _{1 to} C _n The power source circuit 18 supplies power for operating the device 16.

By a connected equalization control switch S ₁ to S _n in parallel to the input state with respect to the capacitor cells C ₁ -C _n, resistor R ₁ to R for equalization control from the capacitor cells C ₁ -C _{n A} current flows with respect to _n , and the charge of the capacitor cell is consumed.

In the present embodiment, FETs are used as the equalization control switches S _{1 to} S _n , but the present invention is not limited to this, and equalization such as high-frequency switches such as diode switches and MEMS (Micro Electro Mechanical Systems) switches is used. A switch capable of controlling on / off based on the output of the cell selection circuit (equalization IC 14 in this embodiment) can be used.

  In this embodiment, an equalization IC 14 (for example, LTC6802 manufactured by Linear Technology Co., Ltd.) including a cell voltage detection circuit and an equalization cell selection circuit is used. However, the cell voltage detection circuit and the equalization cell selection circuit are respectively used. You may comprise independently.

  Note that the arithmetic processing device 16 and the equalization IC 14 both transmit a control command from the arithmetic processing device 16 to the equalization IC 14, or transmit a cell voltage value from the equalization IC 14 to the arithmetic processing device 16, for example. The communication means 20 for communicating in the direction is provided.

By using the equalization control circuit 12 configured as described above, it is possible to measure the effective capacitances of the capacitor cells C _{1 to} C _{n in} the same manner as the flowchart shown in FIG.

The preferred embodiment of the present invention has been described above, but the present invention is not limited to this. For example, in the above embodiment, the cell voltages and voltage measurement times of the capacitor cells C _{1 to} C _n are individually set. The cell voltages of all the capacitor cells C _{1 to} C _n are simultaneously detected by the cell voltage detection circuit, and the cell voltages and voltage measurement times of the capacitor cells C _{1 to} C _n are simultaneously measured. You may make it measure.

Also, a temperature measuring means for measuring the temperature of the capacitor cells C _{1 to} C _n is provided, and when the temperature of the capacitor cell is higher than a predetermined temperature, it is determined as abnormal, and the capacitance measuring operation of the capacitor cell is performed. It is also possible to detect an abnormality such as canceling the operation.

Further, when thus providing a temperature measuring means, changing the temperature at the time of measurement, by keeping obtain a correction value C _v as described above, to use a correction value C _v corresponding to the measured temperature Various modifications can be made without departing from the object of the present invention.

10 Power Storage Device 11 Capacitance Measurement Circuit 12 Equalization Control Circuit 13 Measurement IC
14 Equalization IC
16 arithmetic processing unit 18 power supply circuit 20 communication means 22 power storage unit C ₁ -C _n capacitor cell R ₁ -R _n equalization control resistor S ₁ -S _n equalization control switch 100 life determination device 102 capacitor cell 104 voltage detection Means 106 Inspection circuit 108 Discharge switch 110 Short-circuit switch r Discharge resistance

Claims (11)

In a power storage device including a plurality of capacitor cells, a capacitance measurement system that measures the effective capacitance of the capacitor cells,
Voltage measuring means for detecting a cell voltage of each of the plurality of capacitor cells;
Voltage adjusting means for decreasing or increasing the cell voltage of the plurality of capacitor cells;
An arithmetic processing unit for controlling the voltage measuring means,
The arithmetic processing unit is
Based on the cell voltage of the plurality of capacitor cells measured by the voltage measuring means, determine a measurement start voltage and a measurement end voltage,
Measuring the cell voltage of the capacitor cell by the voltage measuring means, and measuring the voltage measurement time during which the cell voltage of the capacitor cell drops or rises from the measurement start voltage to the measurement end voltage by the voltage adjusting means,
Based on the voltage measurement time, the capacitance of the capacitor cell is calculated, and the capacitance is corrected by a correction value corresponding to the capacitor cell to calculate an effective capacitance. Capacitance measurement system characterized by that. 2. The capacitance measurement system according to claim 1, wherein the arithmetic processing unit is configured to calculate an effective capacitance of the capacitor cell based on Formula 1 below.

The voltage adjusting means is charge consuming means for consuming charges of the plurality of capacitor cells;
The arithmetic processing unit is
In order to consume the charge of the capacitor cell, control is performed so that a current flows from the capacitor cell to the charge consuming means,
The cell voltage of the capacitor cell is measured by the voltage measuring means, and the voltage measurement time for the cell voltage of the capacitor cell to drop from the measurement start voltage to the measurement end voltage is measured. The capacitance measuring system according to claim 1 or 2, characterized by the above. The charge consuming means is an equalization control resistor connected in parallel to the capacitor cell, and the voltage measuring means is a cell voltage detection circuit,
An equalization control switch connected in parallel to the plurality of capacitor cells;
An equalization cell selection circuit for controlling the equalization control switch, and
The equalization control switch connected in parallel to the capacitor cell so that the arithmetic processing unit causes a current to flow from the capacitor cell to the equalization control resistor so as to consume the charge of the capacitor cell. The capacitance measurement system according to claim 3, wherein the equalization cell selection circuit is controlled so as to be in an on state.   5. The capacitance measuring system according to claim 1, wherein the capacitor cell is a lithium ion capacitor. The capacitance measuring system according to any one of claims 1 to 5,
The arithmetic processing unit is
Calculate the capacitance ratio between the effective capacitance of the capacitor cell calculated based on the voltage measurement time and the rated capacity of the capacitor cell;
A deterioration state estimation system for a capacitor cell, wherein the deterioration state of the capacitor cell is estimated based on the capacity ratio. In a power storage device including a plurality of capacitor cells, a capacitance measuring method for measuring an effective capacitance of a capacitor cell,
Measuring cell voltages of the plurality of capacitor cells;
Determining a measurement start voltage and a measurement end voltage based on the measured cell voltages of the plurality of capacitor cells;
Measuring a voltage measurement time during which the cell voltage of the capacitor cell drops or rises from the measurement start voltage to the measurement end voltage by voltage adjusting means;
Calculating a capacitance of the capacitor cell based on the voltage measurement time;
Correcting the capacitance with a correction value corresponding to the capacitor cell and calculating an effective capacitance. The capacitance measuring method according to claim 7, wherein an effective capacitance of the capacitor cell is calculated based on the following formula 1.

Further comprising consuming charges of the plurality of capacitor cells;
9. The capacitance measuring method according to claim 7, wherein a voltage measurement time during which the cell voltage of the capacitor cell drops from the measurement start voltage to the measurement end voltage is measured.   The capacitance measuring method according to claim 7, wherein the capacitor cell is a lithium ion capacitor. A step of measuring an effective capacitance of the capacitor cell by the capacitance measuring method according to any one of claims 7 to 10,
Calculating a capacitance ratio between the effective capacitance of the capacitor cell and the rated capacity of the capacitor cell;
Estimating the deterioration state of the capacitor cell based on the capacity ratio, and a method for estimating the deterioration state of the capacitor cell.

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