JP2016219447A - Voltage holding ratio specification device of electric double layer capacitor and voltage holding ratio specification method of electric double layer capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the time required for specifying the voltage holding ratio of an electric double layer capacitor.SOLUTION: A voltage holding ratio specification device of an electric double layer capacitor includes a charging section 2 performing constant-voltage charging for an inspection object capacitor 11 charged to a rated voltage with a rated voltage, a current detector 3 for detecting a charging current Ich flowing through the capacitor 11 in a constant-voltage charged state with the rated voltage, and outputting while converting into a voltage signal Vi, and a processing section 5 executing the specification processing for acquiring the features of a transient current waveform in a transient period T1 of the charging current Ich, which makes a transition to a steady period where the current value becomes substantially constant, after passing the transient period where the current value decreases gradually in the constant-voltage charged state, based on the voltage signal Vi, and specifying the voltage holding ratio of the capacitor 11 based on the features thus acquired.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a voltage holding ratio specifying device and a voltage holding ratio specifying method for specifying a voltage holding ratio of an electric double layer capacitor.

  As an example of this type of voltage holding ratio specifying device, a leakage current inspection system disclosed in Patent Document 1 below is known. As will be described later, the leakage current is almost proportional to the reduction rate of the charging voltage of the electric double layer capacitor, and therefore the leakage current is almost inversely proportional to the charging voltage holding rate (voltage holding rate) of the electric double layer capacitor. Therefore, this leakage current inspection system is also a voltage holding ratio specifying device for specifying a voltage holding ratio.

  This leakage current inspection system (voltage holding ratio specifying device) includes a charge / discharge device for charging / discharging an electric double layer capacitor (hereinafter also simply referred to as a capacitor), and a charge / discharge device connected to the charge / discharge device through a data communication line. A capacitor leakage current inspection system including a control device for controlling. In this inspection system, the charging / discharging device measures the current flowing through the capacitor while charging the capacitor while maintaining the set voltage for a set time (current flowing during relaxed charging). Data is acquired and the steady current flowing in the capacitor during the set time is calculated.

  In this case, the steady-state current that flows during this relaxed charge has a close relationship with the leakage current, and the conventional neglect test (capacitor is charged to a certain voltage and left as it is for a certain time (72 hours (3 days in JIS D1401)). Compared with the voltage immediately after the charging is completed, the leakage current is evaluated in an indirect manner), which is almost proportional to the decrease rate of the capacitor charging voltage during self-discharge, which has been used to evaluate the leakage current. It has been confirmed that Therefore, in this inspection system, it is possible to evaluate the leakage current by measuring the steady current flowing during relaxation charging. In this inspection system, it is possible to convert the calculated steady-state current into the reduction rate of the charging voltage that has been used for the leakage current evaluation in the conventional standing test in this evaluation.

  This leakage current inspection system evaluates the leakage current as described above, and does not indirectly measure the leakage current from the degree of decrease in the charging voltage of the electric double layer capacitor as in the past. Since the determination is based on the steady-state current at the time of relaxation charging, according to this leakage current inspection system, the leakage current of the capacitor (that is, the reduction ratio of the charging voltage), and thus the charging voltage holding ratio, is inspected. It is possible to shorten the test time.

JP 2003-133189 A (page 2-4, FIG. 1-2)

  However, the above leakage current inspection system (voltage holding ratio specifying device) has the following problems to be solved. That is, in recent years, it has been desired to further shorten the time required for the inspection of the leakage current of the capacitor (inspection for the reduction ratio), that is, equivalently, the time required for the inspection of the voltage holding ratio of the capacitor. However, in this voltage holding ratio specifying device, since it is necessary to measure a steady current, it is necessary to always wait until the current flowing at the time of relaxation charging reaches a steady state, so that it is necessary to specify the voltage holding ratio. There is a problem to be solved that it is difficult to further reduce the time.

  The present invention has been made to solve such a problem, and a voltage holding ratio specifying device for an electric double layer capacitor and an electric double layer capacitor capable of further shortening the time required for specifying the voltage holding ratio of the electric double layer capacitor The main purpose is to provide a method for specifying the voltage holding ratio.

  In order to achieve the above object, a voltage holding ratio specifying device for an electric double layer capacitor according to claim 1 is a charging unit that charges the electric double layer capacitor to be inspected at a rated voltage at a constant voltage with the rated voltage. A current detection unit that detects a current flowing through the electric double layer capacitor in the constant voltage charging state at the rated voltage, converts the current into a voltage signal, and outputs the voltage signal; and a current value gradually decreases in the constant voltage charging state. Based on the voltage signal, the characteristics of the transient current waveform in the transient period of the current that transitions to a steady period in which the current value becomes substantially constant after passing through the transient period, and based on the acquired characteristics And a processing unit that executes specific processing for specifying the voltage holding ratio of the electric double layer capacitor.

  The voltage holding ratio specifying device for an electric double layer capacitor according to claim 2 is the voltage holding ratio specifying device for an electric double layer capacitor according to claim 1, wherein a plurality of electric double layer capacitors having the same specifications as the inspection object are the characteristics. Is stored associating information for associating a plurality of groups generated by grouping together similar ones and a holding ratio range including the voltage holding ratio of the electric double layer capacitor grouped for each of the plurality of groups The processing unit refers to the association information in the specific process, so that the electrical double layer capacitor to be inspected is within the retention rate range associated with the acquired feature. It is specified that the voltage holding ratio is included.

  The voltage holding ratio specifying device for an electric double layer capacitor according to claim 3 is the voltage holding ratio specifying device for the electric double layer capacitor according to claim 1 or 2, wherein the processing unit has a shape of the transient current waveform as the characteristic. Get as.

  The voltage holding ratio specifying device for an electric double layer capacitor according to claim 4 is the voltage holding ratio specifying device for the electric double layer capacitor according to claim 1 or 2, wherein the processing unit takes a predetermined time from the beginning of the transient period. The current value of the transient current waveform at the time when it has elapsed is acquired as the feature.

  The method for specifying the voltage holding ratio of the electric double layer capacitor according to claim 5 includes: a process of performing constant voltage charging at the rated voltage on the electric double layer capacitor charged at the rated voltage; and constant voltage charging at the rated voltage. In the state, the current flowing through the electric double layer capacitor is detected, converted into a voltage signal and output, and the current value is substantially constant after a transient period in which the current value gradually decreases in the constant voltage charging state. Based on the voltage signal, acquire the characteristics of the transient current waveform in the transient period of the current that transitions to the steady period, and specify the voltage holding ratio of the electric double layer capacitor based on the acquired characteristics Execute specific processing.

  According to the voltage holding ratio specifying device for the electric double layer capacitor according to claim 1 and the voltage holding ratio specifying method for the electric double layer capacitor according to claim 4, the voltage holding ratio of the electric double layer capacitor to be inspected is normally determined. The characteristics of the transient current waveform in the transition period before the transition to the period are acquired, and the voltage holding ratio to be inspected is specified based on the characteristics. Specifically, as in the voltage holding ratio specifying device for the electric double layer capacitor according to claim 2, it is associated with the characteristics of the acquired transient current waveform by referring to the acquired association information. The holding ratio range is specified as a holding ratio range including the voltage holding ratio to be inspected.

  Therefore, according to the voltage holding ratio specifying device of the electric double layer capacitor and the voltage holding ratio specifying method of the electric double layer capacitor, unlike the leakage current inspection system (voltage holding ratio specifying device) described in the background art, Since it is not necessary to wait until the current flowing through the electric double layer capacitor reaches a steady state, the time required for specifying the voltage holding ratio to be inspected can be sufficiently shortened.

  According to the apparatus for specifying a voltage holding ratio of an electric double layer capacitor according to claim 3, since the characteristic (characteristic about the shape) appearing in the shape of the transient current waveform for the current flowing through the electric double layer capacitor is acquired, the predetermined As a result, it is possible to perform grouping more accurately in consideration of not only the current value at the time of the current time but also the degree of decrease in the current value. It is possible to more accurately specify the voltage holding ratio to be inspected based on the holding ratio range associated with.

  According to the voltage holding ratio specifying device for the electric double layer capacitor according to claim 4, since only the current value of the transient current waveform at a predetermined time needs to be measured, it is compared with the configuration for measuring the waveform of the transient current waveform. Thus, the apparatus configuration can be simplified, and as a result, the apparatus cost can be reduced.

1 is a configuration diagram of a voltage holding ratio specifying device 1. FIG. 4 is a waveform diagram of a charging current Ich when the voltage holding ratio specifying device 1 charges an electric double layer capacitor 11. FIG. It is a transient current waveform figure in period T1a in Drawing 2 about a plurality of samples. FIG. 4 is a partially enlarged view of FIG. 3.

  Hereinafter, embodiments of a voltage holding ratio specifying device and a voltage holding ratio specifying method for an electric double layer capacitor will be described with reference to the accompanying drawings.

  First, the configuration of the voltage holding ratio specifying device for the electric double layer capacitor will be described with reference to the drawings.

  A voltage holding ratio specifying device 1 as a voltage holding ratio specifying device for an electric double layer capacitor shown in FIG. 1 includes a charging unit 2, a current detecting unit 3, a storage unit 4, and a processing unit 5, and an electric double layer capacitor to be inspected. A voltage holding ratio A of 11 (hereinafter also referred to as a capacitor) is specified.

  The charging unit 2 is controlled by the processing unit 5 so that the capacitor 11 connected between the detection terminals P1 and P2 of the voltage holding ratio specifying device 1 via the probes PL1 and PL2 is charged with a constant current. (Constant current charging operation) and constant voltage charging operation (constant voltage charging operation) can be switched and executed.

  The current detection unit 3 is disposed in a current loop of a current (charging current) Ich that flows when the charging unit 2 charges the capacitor 11, and continuously detects the charging current Ich in time series. The voltage signal Vi (for example, a signal whose voltage value changes in proportion to the current value of the charging current Ich) is converted and output.

  The storage unit 4 is configured by a hard disk device, a semiconductor memory, or the like. Information for specifying the voltage holding ratio A of the capacitor 11 is stored in the storage unit 4 based on the characteristics of a transient current waveform (described later) measured (acquired) when the capacitor 11 to be inspected is charged at a constant voltage. Dre is stored in advance. Specifically, this information Dre functions as association information, and a plurality (n: n is a number) generated by grouping a plurality of electric double layer capacitors (non-defective products) having the same specifications as the capacitor 11 to be inspected. , GPn (an integer greater than or equal to 2) groups GP1, GP2,..., GPn (groups generated by grouping similar features (common features) appearing in the transient current waveform of the electric double layer capacitor): Hereinafter, when not distinguished, it is also referred to as “group GP”), and a holding ratio range including the voltage holding ratio B of the grouped electric double layer capacitors for each of the plurality of groups GP1, GP2,. Rb1, Rb2,..., Rbn (hereinafter also referred to as “retention rate range Rb” when not distinguished).

A procedure for acquiring the association information Dre will be described. First, a plurality of electric double layer capacitors having the same specifications as the capacitor 11 to be inspected are selected at random, and for each selected electric double layer capacitor, the following test procedures defined in JIS D1401 (the first to first tests) The first test is performed according to 3 steps), and the voltage holding ratio B is measured (acquired).
First step: The electric double layer capacitor in a discharged state is charged with a constant current until the charging voltage reaches the rated voltage. Here, the “rated voltage” is a voltage at the limit of the charging voltage that can be safely used by the electric double layer capacitor, and means a rated voltage described in catalogs and specifications of the electric double layer capacitor.
Second step: The electric double layer capacitor charged to the rated voltage is charged at a constant voltage at the same voltage as the rated voltage for the time (300 seconds) specified in the above standard.
Third step: Set the open state between the terminals of the electric double layer capacitor for which constant voltage charging is completed, and measure the inter-terminal voltage (charge voltage) after being left for the time specified in the above standard (72 hours) Then, the ratio of the measured inter-terminal voltage to the rated voltage is calculated as the voltage holding ratio B.

Next, a second test is performed on each electric double layer capacitor whose voltage holding ratio B has been calculated according to the following test procedure (steps a and b) to measure (obtain the characteristics of a transient current waveform, which will be described later. )
Step a: The electric double layer capacitor in a discharged state is charged with a constant current with a constant charging current Ich as shown in FIG. 2 until the charging voltage reaches the rated voltage.
Step b: Measure (acquire) the waveform of the charging current Ich in this constant voltage charged state while further charging the electric double layer capacitor charged to the rated voltage with a constant voltage at the same voltage as the rated voltage. Specifically, as shown in FIG. 2, the charging current Ich in the constant voltage charging state finally passes through a transient period T1 in which the current value gradually decreases and then finally enters a steady period T2 in which the current value becomes constant. In this b-th step, the waveform of the charging current Ich in the transition period T1 before transitioning to the steady period T2 (particularly, the first half period T1a of the transition period T1 where the degree of change in the current value is large) ( Measure the transient current waveform. Depending on the electric double layer capacitor, the degree of change in the current value may be reduced during the period T1a. Even in this case, the waveform of the same period T1a as the other electric double layer capacitors is measured.

  Subsequently, the similar (common) features are grouped for each electric double layer capacitor from which the features have been acquired. Next, for each of the plurality of groups GP generated by the grouping, the range of the voltage holding ratio B of each electric double layer capacitor included in the group GP is obtained as the holding ratio range Rb. Finally, the retention rate range Rb obtained for each of the plurality of groups GP is stored in the storage unit 4 as association information Dre in association with the corresponding group GP. Thereby, acquisition of the association information Dre is completed.

  Thus, in the electric double layer capacitor, there is a correlation between the characteristics appearing in the transient current waveform in the transient period for the charging current Ich during the constant voltage charging and the holding ratio range including the voltage holding ratio. The fact that there is an electric double layer capacitor of 1000F will be described as an example.

  First, the first test was performed on a plurality of samples of the electric double layer capacitor, and the voltage holding ratio B of each sample was measured (acquired). As a result, in these samples, 68.0%, 88.0%, 89.7%, 90.3%, 91.0%, 94.3%, 94.4%, 95.7% in ascending order. A voltage holding ratio B of 95.7% was obtained.

  Next, a second test was performed, and the waveform (transient current waveform) of the charging current Ich in the first half period T1a of the transient period T1 of each sample was measured (acquired). The result is shown in FIG.

  Based on the waveforms of FIG. 3, the acquired waveform of the charging current Ich pays attention to the following different features and is divided into three groups GP (first group GP1, second group GP2, third group GP3). ).

  First, the characteristics of the transient current waveform of the charging current Ich (characteristics regarding the shape of the waveform) for the electric double layer capacitors grouped as the first group GP1 is that the current value is the start of constant voltage charging (in FIG. 3). It reaches a relatively small value (a value less than Ia (about 0.003 A in the figure)) from a relatively early time ta (after about 5 hours in the figure) to the relatively early time ta, and the degree of decrease gradually decreases thereafter. The first feature is that the value decreases toward a value in a steady state (steady value, for example, 0.0003 A).

  The characteristics of the transient current waveform of the charging current Ich (characteristics regarding the waveform shape) for the electric double layer capacitors grouped as the second group GP2 is that the current value is equal to the time ta described above from the start of constant voltage charging. Although the value Ia has not been reached at the time when elapses, the degree of decrease continues to decrease while gradually decreasing, and although not shown in FIG. The second feature is that, when about 40 hours have passed), it reaches a small value almost equal to the steady value for the electric double layer capacitors of the first group GP1 described above.

  The characteristics of the transient current waveform of the charging current Ich for the electric double layer capacitors grouped as the third group GP3 (characteristics regarding the shape of the waveform) are as follows. However, since the degree of decrease suddenly decreases after that, the value of the electric double layer capacitors of the other groups GP1 and GP2 described above is much higher than the steady values for the other groups GP1 and GP2. The third feature is that the steady state is reached at a high value (for example, a value higher by one digit or more like 0.001A).

  Subsequently, for each of the groups GP1, GP2, GP3, the range of the voltage holding ratio B of the samples included in the group GP was obtained as the holding ratio range Rb. In this example, the voltage holding ratio B of the samples included in the first group GP1 is 94.3%, 94.4%, 95.7%, 95.7%, and the samples included in the second group GP2 The voltage holding ratio B was 89.7%, 90.3%, 91.0%, and the voltage holding ratio B of the samples included in the third group GP3 was 68.0%, 88.0%. .

  Therefore, the holding ratio range Rb1 for the voltage holding ratio B of each sample included in the first group GP1 is defined as 93% or more, and the holding ratio range Rb2 for the voltage holding ratio B of each sample included in the second group GP2. Is defined as 89% or more and less than 93%, and the retention rate range Rb3 for the voltage retention rate B of each sample included in the third group GP3 is defined as less than 89%, whereby the retention rate range Rb1 and the first group GP1 It is confirmed that the retention rate range Rb2 and the second group GP2 can be associated with each other, and the retention rate range Rb3 and the third group GP3 can be associated with each other. In other words, in the electric double layer capacitor, there is a correlation between the characteristics appearing in the transient current waveform in the transient period for the charging current Ich during constant voltage charging and the retention ratio range including the voltage retention ratio. It was confirmed.

  The processing unit 5 includes, for example, an A / D converter, a memory, a CPU, and the like, and performs control processing for the charging unit 2 (specifically, processing for setting a current value of the charging current Ich during constant current charging, and Processing for setting a voltage value during constant voltage charging), waveform measurement processing for measuring a transient current waveform of the charging current Ich based on the voltage signal Vi output from the current detection unit 3, and characteristics of the measured transient current waveform And a specific process for specifying the voltage holding ratio A of the capacitor 11 to be inspected based on the acquired characteristic. The processing unit 5 is also configured to be able to execute an output process for outputting the specified voltage holding ratio A. In this output processing, an output device such as a display device is provided in the voltage holding ratio specifying device 1, and the voltage holding rate A is output to this output device, or another device provided outside the voltage holding ratio specifying device 1. Or the voltage holding ratio A can be output.

  Next, the operation of the voltage holding ratio specifying device 1 will be described with reference to the drawings together with the voltage holding ratio specifying method. In this example, as an example, the capacitor 11 having the same specification as that of the above-described sample is to be inspected, and the storage unit 4 stores in advance the above-described association information Dre (information described in FIG. 3) regarding this sample. It is assumed that

  In the voltage holding ratio specifying device 1, the processing unit 5 specifies the voltage holding ratio A of the capacitor 11 in a state where the capacitor 11 to be inspected is connected between the detection terminals P1 and P2 via the probes PL1 and PL2. To execute the process.

  In this process, the processing unit 5 first executes a control process for the charging unit 2, and the current value of the charging current Ich at the time of constant current charging and the voltage value of the charging voltage at the time of constant voltage charging (this example) Then, in order to charge the capacitor 11 to the rated voltage during constant current charging, the charging unit 2 is set to the rated voltage value) and the charging unit 2 is started to perform a charging operation.

  As a result, the charging unit 2 first performs constant current charging with the charging current Ich of the set current value on the capacitor 11, and then when the charging voltage value of the capacitor 11 reaches the rated voltage value. Then, switching from constant current charging to constant voltage charging continues to charge the capacitor 11. When the capacitor 11 that has already been charged to the rated voltage by another charging device or the like is to be inspected, the voltage holding ratio specifying device 1 omits the constant current charging operation and starts from the constant voltage charging operation.

  The current detection unit 3 continuously detects the charging current Ich flowing through the capacitor 11 in time series while the charging unit 2 is charging the capacitor 11, converts the current into a voltage signal Vi, and outputs the voltage signal Vi to the processing unit 5.

  Next, the processing unit 5 executes a waveform measurement process. In this waveform measurement process, the processing unit 5 measures the waveform (transient current waveform) of the charging current Ich in this period T1a based on the voltage signal Vi output from the current detection unit 3 in the period T1a shown in FIG. (get.

  Subsequently, the processing unit 5 executes feature acquisition processing. In this feature acquisition process, the processing unit 5 uses each feature (in this example, the first feature) when the features appearing in the acquired transient current waveform are grouped into each group GP included in the association information Dre. The characteristic of the transient current waveform of the charging current Ich is acquired by determining which of the characteristic, the second characteristic, and the third characteristic).

  Next, the processing unit 5 executes a specific process. In this specifying process, the processing unit 5 specifies the retention rate range Rb associated with the characteristics of the acquired transient current waveform of the charging current Ich by referring to the association information Dre stored in the storage unit 4. (In this example, any one of the retention ranges Rb1 to Rb3 is specified). Thereby, the specific process is completed. Finally, the processing unit 5 performs an output process and outputs that the voltage holding ratio A of the capacitor 11 to be inspected is a value included in the holding ratio range Rb specified in this way. Thereby, the process for specifying the voltage holding ratio A of the capacitor 11 is completed.

  As described above, in the voltage holding ratio specifying device 1 and the voltage holding ratio specifying method for this capacitor (electric double layer capacitor), the current value of the charging current Ich measured in the state of constant voltage charging is constant. Based on the characteristics of the transient current waveform for the charging current Ich in the transition period T1 (specifically, the period T1a) before the transition to the period T2, the voltage holding ratio A of the capacitor 11 is specified. Specifically, a plurality of group GPs generated by grouping a plurality of electric double layer capacitors having the same specifications as the inspection object into those having similar (common) characteristics as described above, and a group for each of the plurality of group GPs The association information Dre for associating with the holding ratio range Rb including the voltage holding ratio B of the converted electric double layer capacitor is acquired in advance, and when specifying the voltage holding ratio A of the capacitor 11 to be inspected, the charging current described above is used. By measuring (acquiring) the characteristics of the transient current waveform for Ich and referring to the acquired association information Dre, the retention ratio range Rb associated with the characteristics of the acquired transient current waveform of the charging current Ich Is specified as a holding ratio range including the voltage holding ratio A of the electric double layer capacitor to be inspected.

  Therefore, according to the voltage holding ratio specifying device 1 and the voltage holding ratio specifying method of this capacitor (electric double layer capacitor), unlike the leakage current inspection system (voltage holding ratio specifying device) described in the background art, charging is performed. Since there is no need to wait until the current Ich reaches a steady state, the time required for specifying the voltage holding ratio A of the capacitor 11 can be sufficiently shortened.

  Further, according to the capacitor voltage holding ratio specifying device 1 and the voltage holding ratio specifying method, the feature (feature concerning the shape) appearing in the shape of the transient current waveform for the charging current Ich is obtained (measured). In addition to the current value at a predetermined time, it is possible to perform grouping more accurately in consideration of the degree of decrease in the current value, and the like. Based on the holding ratio range Rb associated with the group GP, the voltage holding ratio A of the capacitor 11 can be specified more accurately.

  Note that the characteristics of the transient current waveform used when grouping the transient current waveforms of the charging current Ich are not limited to the characteristics of the shape of the transient current waveform as in the above-described example. As shown in FIG. 4, the current value of the transient current waveform when the predetermined time tb (13 hours in this example) has elapsed from the beginning of the transient period T1 (at 0 hour) (the current at the circle in the figure) It is also possible to adopt a configuration in which (value) is acquired as a characteristic of the transient current waveform. In this case, as shown in the figure, capacitors having characteristics with respect to the transient current waveform in which the current value at the predetermined time tb of the transient current waveform is equal to or less than the current threshold value Ith1 are grouped as a first group, and the current threshold value Ith1 is set. Capacitors having a characteristic regarding the transient current waveform that is less than or equal to the overcurrent threshold Ith2 are grouped as a second group, and capacitors having a characteristic about the transient current waveform that exceeds the current threshold Ith2 are grouped as a third group.

  According to this configuration, since it is only necessary to measure the current value of the transient current waveform at the predetermined time tb, the apparatus configuration can be simplified as compared with the configuration for measuring the waveform of the transient current waveform. As a result, the device cost can be reduced.

DESCRIPTION OF SYMBOLS 1 Voltage holding ratio specific device 2 Charging part 3 Current detection part 5 Processing part 11 Capacitor Dre Association information Ich charging current

Claims (5)

A charging unit that performs constant voltage charging at the rated voltage for the electric double layer capacitor to be inspected that is charged at the rated voltage;
A current detection unit that detects a current flowing in the electric double layer capacitor in a constant voltage charged state at the rated voltage and converts the current into a voltage signal and outputs the current signal;
Based on the voltage signal, the characteristics of the transient current waveform in the transient period of the current that transitions to a steady period in which the current value becomes substantially constant after a transient period in which the current value gradually decreases in the constant voltage charging state. And a processing unit that executes a specifying process for specifying the voltage holding ratio of the electric double layer capacitor based on the acquired characteristics. A plurality of groups generated by grouping a plurality of electric double layer capacitors having the same specifications as the inspection object into those having similar characteristics, and the group of the electric double layer capacitors grouped for each of the plurality of groups A storage unit storing association information for associating with a holding ratio range including the voltage holding ratio;
When the processing unit refers to the association information in the specific process, the voltage holding ratio of the electric double layer capacitor to be inspected is included in the holding ratio range associated with the acquired feature. 2. The voltage holding ratio specifying device for an electric double layer capacitor according to claim 1.   The voltage holding ratio specifying device for an electric double layer capacitor according to claim 1, wherein the processing unit acquires the shape of the transient current waveform as the characteristic.   3. The voltage holding ratio specifying device for an electric double layer capacitor according to claim 1, wherein the processing unit acquires, as the characteristic, a current value of the transient current waveform when a predetermined time has elapsed from the beginning of the transient period. A process of charging the electric double layer capacitor charged to the rated voltage at a constant voltage at the rated voltage;
A process of detecting a current flowing in the electric double layer capacitor in a constant voltage charging state at the rated voltage and converting it to a voltage signal and outputting the detected current;
The voltage signal is characterized by a transient current waveform in the transient period of the current that transitions to a steady period in which the current value becomes substantially constant after a transient period in which the current value gradually decreases in the constant voltage charging state. And a specifying process for specifying the voltage holding ratio of the electric double layer capacitor based on the acquired characteristics.

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