Deterioration diagnostic device and deterioration diagnostic method for capacitor

Abstract

This capacitor deterioration diagnostic device (1) comprises: an information acquisition unit (3) that measures and acquires the physical quantity of a capacitor; a charge / discharge circuit (5) that charges and discharges the capacitor; and a control device (4) that, on the basis of the physical quantity of the capacitor acquired by the information acquisition unit (3), controls the charge / discharge circuit (5) so that the measurement range of the charge / discharge characteristics in a non-standard measurement environment of the capacitor is wider than the measurement range of the charge / discharge characteristics in a standard measurement environment of the capacitor. When the capacitor is charged and discharged, deterioration of the capacitor is diagnosed according to the difference between properties of the initial period of usage and properties after a lapse of time, with regard to the electrical characteristics of the capacitor.

Description

Capacitor degradation diagnostic device and degradation diagnostic method

[0001] The present application relates to a deterioration diagnosis for a capacitor.

[0002] An electric double-layer capacitor (hereinafter referred to as EDLC) is a power storage device used in voltage sag compensation devices or vehicles. It is known that EDLCs decrease in capacitance and increase in internal resistance due to aging. The degradation state of such EDLCs can be estimated based on the capacitance or internal resistance calculated from the voltage fluctuation, current, and charge / discharge time during charging and discharging.

[0003] For example, in the capacitance evaluation method described in Patent Document 1, an EDLC is discharged to a predetermined voltage at a constant current, and then the capacitance is calculated using the voltage of the EDLC after a certain time has elapsed. Patent Document 1 also describes a conventional capacitance calculation method, which is a method of determining the slope of a portion where a linear change is established in the voltage waveform during discharge.

[0004] JP 2010-139304 A

[0005] Kinoshita, "Characteristics and Effective Use of Electric Double Layer Capacitors (EDLC)," First Edition, Nikkan Kogyo Shimbun, March 30, 2010, pp. 38-44; T. Funaki, "Evaluating Energy Storage Efficiency by Modeling the Voltage and Temperature Dependency in EDLC Electrical Characteristics," IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 25, NO. 5, MAY 2010

[0006] However, Patent Document 1 requires a certain period of pause at the end of discharge, making it inapplicable to devices that do not allow pauses. Furthermore, since the voltage fluctuation of an EDLC immediately after discharge begins after degradation or in a low-temperature environment becomes a curve, the range of data (the range of the linear portion) that can be used to calculate capacitance in conventional calculation methods narrows if the discharge time is fixed. This increases the impact of measurement variations, potentially resulting in reduced accuracy in lifespan estimation or degradation diagnosis before and after degradation, or at different temperatures.

[0007] The present application discloses a technique for solving the above-mentioned problems, and aims to provide a capacitor degradation diagnosis device that can maintain a constant accuracy of degradation diagnosis even when the capacitor deteriorates or when the capacitor temperature drops below 25°C.

[0008] The capacitor degradation diagnosis device disclosed in the present application comprises: an information acquisition unit that measures and acquires physical quantities of a capacitor; a charge / discharge circuit that charges and discharges the capacitor; and a control device that controls the charge / discharge circuit based on the physical quantities of the capacitor acquired by the information acquisition unit so that the measurement range of the charge / discharge characteristics, which are electrical characteristics that occur over time when charging or discharging, in a non-standard measurement environment of the capacitor is wider than the measurement range of the charge / discharge characteristics in the standard measurement environment of the capacitor, and is characterized in that the degradation of the capacitor is diagnosed based on the difference between the electrical characteristics of the capacitor at the beginning of use and the characteristics after the passage of time when the capacitor is charged and discharged.

[0009] According to the capacitor degradation diagnosis device disclosed in the present application, it is possible to provide a capacitor degradation diagnosis device that can maintain constant accuracy in degradation diagnosis even when the capacitor deteriorates or when the temperature of the capacitor changes to 25°C or below.

[0010] 1 is a diagram showing the overall configuration of a capacitor degradation diagnosis device according to a first embodiment; FIG. 2 is a diagram showing the configuration of an information acquisition unit of the capacitor degradation diagnosis device according to the first embodiment; FIG. 3 is a diagram showing the configuration of a control device of the capacitor degradation diagnosis device according to the first embodiment; FIG. 4 is a diagram showing the configuration of a degradation diagnosis unit of the capacitor degradation diagnosis device according to the first embodiment; FIG. 5 is a diagram showing voltage fluctuations and current waveforms of an EDLC when it is deteriorated or in a room temperature environment according to the first embodiment; FIG. 6 is a diagram showing voltage fluctuations and current waveforms of an EDLC when it is deteriorated or in a low temperature environment according to the first embodiment; FIG. 7 is a diagram showing a flowchart of EDLC degradation diagnosis according to the first embodiment; FIG. 8 is a diagram showing dV / dt calculated from voltage fluctuations during discharge in the capacitor degradation diagnosis device according to the second embodiment; FIG. 9 is a diagram showing the overall configuration of a capacitor degradation diagnosis device according to the third embodiment; FIG. 10 is a diagram showing the relationship between the time of use or the amount of deterioration of an EDLC according to the third embodiment and the time of a curved portion; FIG. 11 is a diagram showing the relationship between the temperature of an EDLC according to the third embodiment and the time of a curved portion; FIG. 12 is a diagram showing the discharge characteristics of an EDLC before deterioration or in a room temperature environment according to the fourth embodiment; FIG. 13 is a diagram showing an example of hardware included in the capacitor degradation diagnosis devices according to the first to fourth embodiments; FIG. 14 is a diagram showing an example of the overall configuration of a capacitor degradation diagnosis device other than the first to third embodiments.

[0011] Hereinafter, a capacitor degradation diagnostic device according to a first embodiment will be described with reference to the drawings.

[0012] First Embodiment Fig. 1 is a diagram showing the overall configuration of a degradation diagnostic device for an electric double layer capacitor (EDLC) according to a first embodiment (hereinafter, also simply referred to as a "degradation diagnostic device for a capacitor").

[0013] 1, a capacitor degradation diagnosis device 1 (see the dotted-line frame (bottom)) includes an information acquisition unit 3, a control unit 4, and a charge / discharge circuit 5, and performs degradation diagnosis of an electric double layer capacitor 2 (EDLC 2) by a degradation diagnosis unit 6 using the electrical characteristics (e.g., voltage) of the capacitor as an index. Note that the diagnosis results may also be used to predict a lifespan.

[0014] The EDLC 2 can be of various shapes, such as cylindrical, rectangular, or laminated. It may also be configured as a module in which multiple EDLCs are connected in series or parallel. Furthermore, a lithium ion capacitor may be used instead of the EDLC.

[0015] 2 is a diagram showing the configuration of the information acquisition unit 3. As shown in FIG. 2, the information acquisition unit 3 is made up of a voltage measurement unit 31, a current measurement unit 32, a temperature measurement unit 33, and an output unit 34. The voltage measurement unit 31 measures the voltage of the EDLC 2. The current measurement unit 32 measures the current flowing through the EDLC 2. The temperature measurement unit 33 is made up of a temperature sensor using, for example, a thermistor, and measures the temperature of the EDLC 2. The measured voltage, current, and temperature of the EDLC 2 are output to the control device 4 by the output unit 34.

[0016] 3 is a diagram showing the configuration of the control device 4. As shown in FIG. 3, the control device 4 is composed of an input unit 41, a charge / discharge control unit 42, and an output unit 43. The input unit 41 receives voltage, current, and temperature data of the EDLC 2 output from the information acquisition unit 3. Based on the data from the input unit 41, the charge / discharge control unit 42 determines the range of charge / discharge time or voltage to be used for deterioration diagnosis, and controls the charge / discharge circuit 5 via the output unit 43. The charge / discharge circuit 5 may be any circuit as long as it is capable of charging or discharging the EDLC 2.

[0017] 4 is a diagram showing the configuration of the degradation diagnosis unit. As shown in FIG. 4, the degradation diagnosis unit 6 is composed of an input unit 61, a calculation unit 62, and an output unit 63. The input unit 61 receives data such as the voltage, current, and temperature of the EDLC 2 output from the information acquisition unit 3. The calculation unit 62 calculates the capacitance or internal resistance (value) based on the data from the input unit 61. The calculation result is output to a monitor, a recording device, etc. by the output unit 63. It is also possible for the calculation unit 62 to predict the life of the EDLC from the transition of the capacitance or internal resistance value due to degradation, and output the result to a monitor, a recording device, etc.

[0018] Here, a general method for calculating the capacitance of an EDLC will be described. Figure 5 shows the voltage fluctuation and current waveform of an EDLC before degradation (when not degraded) or in a room temperature environment (hereinafter also referred to as the reference measurement environment). The term "before degradation (when not degraded)" refers to a new product in which the capacitance has not decreased. In other words, the capacitance at the beginning of use (hereinafter also simply referred to as the initial state) is used as the reference, and the capacity retention rate is 100%. The "room temperature environment" refers to a temperature around 25°C, but a high temperature environment (25°C or higher) may also be used because similar voltage fluctuations occur at temperatures above 25°C.

[0019] It is known that in low-temperature environments (here, this generally refers to environments with temperatures lower than room temperature, and more specifically to temperature environments below 0°C), the internal resistance of EDLC changes significantly, with the internal resistance increasing in a curved fashion as the temperature drops, and that this influences the terminal voltage of EDLC at -10°C when discharging lower and the terminal voltage when charging higher. It is also important to note that capacitance has the characteristic of decreasing when the voltage drops below the rated voltage (see, for example, Non-Patent Documents 1 and 2).

[0020] As shown in Fig. 5, the initial voltage of the EDLC is V0. When discharging is performed at a current value I from time t1 to t2, the voltage of the EDLC changes from V1 to V2. Since the capacitance C of the EDLC uses the portion where the change in the voltage waveform (the shape of the change in voltage value over time) becomes linear, in Fig. 5 it is calculated using the following formula (1) using ΔV, which is the difference between V1 and V2, and Δt, which is the difference between t1 and t2.

[0021] Capacitance C = (I × (t2 - t1)) / (V1 - V2) = (I × Δt) / ΔV (1) Note that Δt / ΔV on the right side of equation (1) is the reciprocal of the slope indicated by the change in the linear portion in FIG. 5, so the capacitance can be calculated by multiplying the reciprocal of the slope dV / dt when the linear portion is linearly approximated by the current value. Also, although the voltage fluctuation during discharge is illustrated here, the capacitance can also be calculated from the voltage fluctuation during charge. Note that the internal resistance R of the EDLC can be calculated using the above I and ΔV from R = ΔV / I.

[0022] 6 shows voltage fluctuations and current waveforms of an EDLC during degradation or in a low-temperature environment. A degradation state refers to a state in which the capacitance has decreased from that of a new EDLC and the current capacity retention rate is lower than the initial capacity retention rate. For example, the capacity retention rate of a new EDLC is 100%, and this value is 99% or less (hereinafter referred to as the threshold value). Furthermore, a low-temperature environment refers to a temperature below 25°C, preferably 0°C or less, as described above.

[0023] When an EDLC deteriorates (in a low-temperature environment), the voltage fluctuation at the beginning of discharge becomes curved rather than linear due to the effects of ion diffusion. If the discharge end time t2 or discharge end voltage V2 is fixed, the proportion of the linear portion of the voltage fluctuation during discharge decreases (ΔV > ΔVa, Δt > Δta). Therefore, the range of data used to calculate the capacitance narrows, increasing the influence of measurement variations in voltage, etc. As a result, the accuracy of deterioration diagnosis may decrease.

[0024] Therefore, when the EDLC is deteriorated or in a low-temperature environment (hereinafter also referred to as a non-reference measurement environment), the same diagnostic accuracy as in the reference measurement environment can be maintained by controlling the discharge time. That is, by comparing Figures 5 and 6, the discharge time is lengthened or the discharge end voltage is lowered so that Δta ≥ Δt or ΔVa ≥ ΔV.

[0025] This ensures that the time required for voltage fluctuation in the non-reference measurement environment is equal to or longer than the time required for the linear portion of the voltage fluctuation in the reference measurement environment. In practice, it is better to shorten the time required for degradation diagnosis, so ultimately it is desirable to control the relationship so that Δta = Δt.

[0026] Next, an example of a method for diagnosing deterioration of the capacitor of the EDLC 2 according to the first embodiment will be described.

[0027] 7 is a flowchart showing the degradation diagnosis of an EDLC. First, in step S1, charging or discharging of the EDLC is started. In step S2, the time of the curved portion is measured. Next, in step S3, charging or discharging is extended for a time equal to or longer than the time measured in step S2, and in step S4, charging or discharging is continued for a certain period of time. Finally, in step S5, the capacitance and internal resistance are calculated, and the degradation diagnosis is completed.

[0028] 7, the control is based on time, but it may also be based on voltage. In the case of voltage control, the discharge cut-off voltage is reduced by the difference Vb (=V1-Va1) between the voltage V1 in the reference measurement environment and the voltage Va1 in the non-reference measurement environment.

[0029] Here, the time of the curved portion is measured in step S2, but the relationship between the temperature of the EDLC and the time of the curved portion, or the relationship between the capacitance and the time of the curved portion, may be stored as a look-up table or the like, and may be referenced each time for control.

[0030] As described above, the capacitor degradation diagnosis device of the first embodiment can ensure a time period during which electrical characteristics (voltage change over time, also referred to as time fluctuation of voltage change) similar to those in the reference measurement environment become linear by lengthening the discharge time or widening the voltage range in a non-reference measurement environment. The magnitude of voltage change over a certain time range is also referred to as the amount of change over time. As a result, the impact of measurement variation in the non-reference measurement environment can be reduced and can be made to the same level as that in the reference measurement environment, thereby maintaining diagnostic accuracy (e.g., accuracy of error included in capacitance calculation).

[0031] Furthermore, the capacitor degradation diagnosis device of the first embodiment can be applied not only to electric double-layer capacitors but also to lithium-ion capacitors (devices that calculate capacitance from the slope of voltage fluctuations during charging and discharging), as described above. While the first embodiment has been described primarily in terms of the discharge of a capacitor, the device can also be applied to the charge of a capacitor. That is, in capacitor degradation diagnosis, particular attention is paid to the characteristics during discharge, in which voltage changes significantly over time, or the characteristics during charge, and the assessment criteria often include whether or not these characteristics have deteriorated. Therefore, hereinafter, when describing both the characteristics during discharge and the characteristics during charge, the term "charge and discharge characteristics" is used. That is, the charge and discharge characteristics refer to electrical characteristics, such as voltage, that change over time during charging or discharging. These charge and discharge characteristics change significantly during charging or discharging.

[0032] Second Embodiment In the second embodiment, a method for controlling the charge and discharge time will be described. The overall configuration of the degradation diagnosis device used here is the same as that in the first embodiment, and therefore a description thereof will be omitted. As described in the first embodiment, in a non-standard measurement environment, the voltage fluctuation of an EDLC immediately after the start of charge and discharge becomes curved rather than linear. Therefore, using the voltage measured by the information acquisition unit 3, the control device 4 calculates dV / dt by differentiating the voltage with respect to time.

[0033] 8 is a graph showing the slope dV / dt obtained from the voltage fluctuation (also called voltage change) during discharge. In the reference measurement environment, the dashed line C in the graph a As shown in Fig. 1, due to the effect of the voltage drop immediately after the start of discharge, dV / dt momentarily shows a large (negative) value, but after that, the voltage fluctuation becomes linear, so the absolute value becomes a constant (negative) value S that is smaller than the initial value. a This becomes:

[0034] On the other hand, in the non-standard measurement environment, a curved portion exists for a certain period of time immediately after the start of discharge (see FIG. 6). b As shown in Fig. 8, dV / dt fluctuates for a certain period of time (the time during which dV / dt fluctuates is represented as t b ), and then a constant value S bTherefore, the time it takes for dV / dt to reach a constant value, t b (See the thick solid line portion shown as the Cb extension in FIG. 8.) This makes the duration of the linear portion in the reference measurement environment equal to the duration of the linear portion in the non-reference measurement environment.

[0035] In the above, the control was described so that the time of the linear portion in the reference measurement environment and the time of the linear portion in the non-reference measurement environment are equal. However, the extension time is the time to reach a certain value (t b Strictly speaking, the slope is not a completely constant value, but contains some fluctuations, so the constant value is determined taking this into consideration.

[0036] In addition, in the above, due to the nature of the equipment used, when discharging, if it is difficult to calculate dV / dt instantaneously and extend the discharge time, the t b Then, if the time of the curved portion measured is significantly different from the time of the curved portion measured previously, b By correcting the value and performing the diagnosis again, there is no practical problem even if the calculation processing speed is slow.

[0037] As described above, by using dV / dt, which is the value obtained by differentiating the voltage during discharge with respect to time, the discharge time of the linear portion in the reference measurement environment and the non-reference measurement environment can be made equal (or longer), so the influence of measurement variations can be made the same as (reduced to) that in the reference measurement environment, and the accuracy of deterioration diagnosis can be maintained constant. Note that in the second embodiment, the explanation has been limited to matters related to discharge time, but the same explanation can be applied to matters related to charge time as well as discharge time, and the same effect can be obtained.

[0038] As described above, by setting a longer charge / discharge time in the non-reference measurement environment, it is possible to ensure a time for linear change in the non-reference measurement environment, just as in the reference measurement environment. As a result, it is possible to suppress the effects of measurement variations in the non-reference measurement environment, just as in the reference measurement environment, and therefore it is possible to maintain diagnostic accuracy (reducing the error included in the capacitance calculation to the same or less).

[0039] Third Embodiment In a third embodiment, a method of controlling time or voltage different from that in the second embodiment will be described.

[0040] 9 is a diagram showing the overall configuration of an EDLC capacitor degradation diagnostic device 1a (see the dotted line frame (bottom)) according to the third embodiment. In addition to the configuration of the first embodiment, a storage unit 7 is provided. The storage unit 7 stores voltage data at the time of EDLC degradation diagnostic data measurement, the value of dV / dt obtained by differentiating the voltage with respect to time, and the time t of the curved portion. b etc. are recorded.

[0041] FIG. 10 shows the relationship between the time of use or the amount of deterioration of the EDLC and the time t b As shown in FIG. 10, the relationship between t b By recording the past b From the transition of t b In FIG. 10, it is possible to predict t b By utilizing the fact that is linear, b is predicted.

[0042] In addition, between the first and second diagnosis, t b Since it is impossible to predict the time t, as described in the first and second embodiments, it is sufficient to appropriately control the charge / discharge circuit or lengthen the charge / discharge time by an appropriate amount. b From the transition of t b can be predicted.

[0043] This eliminates the need to differentiate the voltage with respect to time before and after degradation, and simply gives bThe predicted t b Discharged using the measured t b If there is a difference, compare it with the actual measured value. b Record the next time b By using it to predict the temperature, measurement accuracy can be improved.

[0044] FIG. 11 shows the relationship between the temperature of the EDLC and the time t b This is a graph showing the relationship between t and the temperature measured. b Record the value of t b Taking advantage of the linearity of b If the relationship is not linear, it may be predicted using a quadratic function or other methods. For example, all the t b Instead of using the data of t b Select two points, and start from the approximate equation of the line connecting the two points, and calculate t at the temperature to be measured. b may be predicted.

[0045] As mentioned above, the t b By using the data and controlling the discharge time, it is possible to simplify the calculation process. In other words, by using the data on the time of the curved portion of the voltage change measured up to now and controlling the discharge time, it is possible to simplify the calculation process using dV / dt. Note that although the case of controlling time has been described here, it is also possible to similarly apply to the case of controlling voltage.

[0046] Fourth Embodiment In the fourth embodiment, the degradation diagnosis device does not control the charge / discharge time or voltage range in degradation diagnosis. Also, the time tb of the curved portion in a non-reference measurement environment (after degradation or a low-temperature environment) is assumed to be known by prior evaluation or the like and recorded in the storage unit 7. Note that the overall configuration is the same as in the third embodiment, and therefore a detailed description thereof will be omitted here.

[0047] 12 is a diagram showing the discharge characteristics in the reference measurement environment. In the first to third embodiments, the discharge time in the reference measurement environment (before deterioration or in a room temperature environment) is Δt. In the present embodiment, however, the discharge time is tb The time (Δt + t b ) is the discharge time in the standard measurement environment.

[0048] In the discharge under the standard measurement environment, the voltage fluctuation in the linear part is Δt + t b However, data for Δt seconds is used to calculate the capacitance. In a non-standard measurement environment, the data for the linear part is t b However, since this is added to the discharge time in advance, data from the linear portion similar to that in the reference measurement environment can be used in non-reference measurement environments.

[0049] As described above, the discharge time Δt in the reference measurement environment is the time t b By adding this, even if the capacitor deteriorates or the temperature of the capacitor changes, the time of the linear portion used to calculate the capacitance can be set with the same measurement accuracy as in the standard measurement environment, and the accuracy of deterioration diagnosis can be maintained constant.

[0050] As in the first to third embodiments, it is also possible to control by voltage rather than time. In this case, the discharge cut-off voltage may be changed from V2 to V2-Vb (=V2-(V1-Va1)). Furthermore, the above description has been given of specific implementation details for discharging, but the specific implementation details are similar for charging. In other words, even if the same control method as above is implemented for charging, the same effect as in discharging can be obtained.

[0051] In the above-described first to fourth embodiments, the hardware 100 of the control device 4 and the degradation diagnosis unit 6, which are the main components of the capacitor degradation diagnosis device 1, and the hardware 100a of the control device 4 and the degradation diagnosis unit 6, which are the main components of the capacitor degradation diagnosis device 1a, may each include, as an example, a processor 101 and a storage device 102 as shown in Fig. 13. In addition, in the above-described third and fourth embodiments, the storage unit 7 may include, as an example, at least the storage device 102 of the processor 101 and the storage device 102 shown in Fig. 13 as its component.

[0052] Here, the storage device 102 includes a volatile storage device such as a random access memory (not shown) and a non-volatile auxiliary storage device such as a flash memory. Alternatively, an auxiliary storage device such as a hard disk may be included instead of the flash memory. The processor 101 executes a program input from the storage device 102. In this case, the program is input from the auxiliary storage device to the processor 101 via the volatile storage device. The processor 101 may output data such as calculation results to the volatile storage device of the storage device 102, or may store the data in the auxiliary storage device via the volatile storage device.

[0053] Although various exemplary embodiments and examples are described in this application, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless variations not illustrated are contemplated within the scope of the technology disclosed in this specification. For example, this includes cases where at least one component is modified, added, or omitted, or where at least one component is extracted and combined with components of another embodiment.

[0054] Specifically, for example, in the above description, as shown in FIG. 1, the information acquisition unit 3 and the charge / discharge circuit 5 constitute part of the degradation diagnosis device 1. However, this is not limited to this. As shown in FIG. 14, the information acquisition unit 3 and the charge / discharge circuit 5 are not components of the degradation diagnosis device 1, and the degradation diagnosis device 1b may consist only of the degradation diagnosis unit 6 and the control device 4 (see the dotted line frame (bottom)). In such a case, information is exchanged between the information acquisition unit 3 and the charge / discharge circuit 5 and the degradation diagnosis device 1b by wireless communication or the like. The degradation diagnosis unit, having obtained information from the information acquisition unit 3, is configured to send control command information to the control device 4. The degradation diagnosis device 1b configured in this way also achieves the same effects as the above-mentioned degradation diagnosis devices 1 and 1a.

[0055] 1, 1a, 1b Degradation diagnosis device, 2 Electric double layer capacitor (EDLC), 3 Information acquisition unit, 31 Voltage measurement unit, 32 Current measurement unit, 33 Temperature measurement unit, 34 Output unit, 4 Control device, 41 Input unit, 42 Charging / discharging control unit, 43 Output unit, 5 Charging / discharging circuit, 6 Degradation diagnosis unit, 61 Input unit, 62 Calculation unit, 63 Output unit, 7 Memory unit, 100, 100a Hardware, 101 Processor, 102 Storage device

Claims

1. An information acquisition unit that measures and acquires a physical quantity of a capacitor; A charge / discharge circuit that charges and discharges the capacitor; Based on the physical quantity of the capacitor acquired by the information acquisition unit, in a non-reference measurement environment of the capacitor, a control device that controls the charge / discharge circuit so that a measurement range of charge / discharge characteristics, which are electrical characteristics accompanying the passage of time during charging or discharging, is wider than a measurement range of charge / discharge characteristics in a reference measurement environment of the capacitor; Comprising: Diagnosing deterioration of the capacitor based on a difference between an initial property and a property after the passage of time of the electrical characteristics of the capacitor when the capacitor is charged and discharged; A capacitor deterioration diagnosis device characterized by the above.

2. Comprising a deterioration diagnosis unit that diagnoses performance deterioration of the capacitor using the electrical characteristics of the capacitor as an index; The deterioration diagnosis unit calculates the electrical characteristics of the capacitor and the amount of change in the electrical characteristics based on the physical quantity obtained from the information acquisition unit, and diagnoses deterioration of the capacitor based on whether the amount of change from the initial value of the calculated electrical characteristics of the capacitor exceeds a predetermined threshold value; The capacitor deterioration diagnosis device according to claim 1, characterized by the above.

3. The measurement range of the charge / discharge characteristics is a measurement range of temporal variation of voltage during charge / discharge; The control device: Controls the charge / discharge circuit to make the range of temporal variation of voltage during charge / discharge in the non-reference measurement environment of the capacitor coincide with the range of temporal variation of voltage during charge / discharge in the reference measurement environment of the capacitor; Performs control to make the charge / discharge time in the non-reference measurement environment of the capacitor longer than the charge / discharge time in the reference measurement environment of the capacitor with respect to the charge / discharge circuit; The capacitor deterioration diagnosis device according to claim 1 or 2, characterized by the above.

4. The measurement range of the charge / discharge characteristics is a measurement range of the amount of change in voltage during charge / discharge; The control device: Makes the temporal change amount of a portion where the electrical characteristics during charge / discharge in the non-reference measurement environment of the capacitor are linear coincide with the temporal change amount of a portion where the electrical characteristics during charge / discharge in the reference measurement environment of the capacitor are linear; Perform control to make the length of the portion where the electrical characteristics during charging and discharging in the reference measurement environment of the capacitor are linear greater than the length of the portion where the electrical characteristics during charging and discharging in the non-reference measurement environment of the capacitor are linear, with respect to the charge / discharge circuit. The capacitor degradation diagnosis device according to claim 1 or 2, characterized in that.

5. The control device is With respect to the charge / discharge circuit, perform control to make the charge / discharge time of the capacitor in the non-reference measurement environment longer than the charge / discharge time of the capacitor in the reference measurement environment for a time period from the start of charge / discharge until the value obtained by differentiating the voltage fluctuation during charge / discharge of the capacitor with respect to the charge / discharge time becomes a constant value. The capacitor degradation diagnosis device according to claim 1 or 2, characterized in that.

6. Comprising a storage unit for recording the voltage fluctuation during charge and discharge of the capacitor, The control device is With respect to the charge / discharge circuit, perform control to set the charge / discharge time in a new measurement or the charge / discharge time in a low-temperature environment measured for the first time, from the data of the portion where the time variation of the measured voltage is curved. The capacitor degradation diagnosis device according to claim 1 or 2, characterized in that.

7. The control device is With respect to the charge / discharge circuit, for the time of the portion where the voltage fluctuation during charge and discharge of the capacitor in the non-reference measurement environment is curved, or when the voltage change amount is known, in advance, considering the time of the portion where the voltage fluctuation is curved or the voltage change amount of the portion where the voltage fluctuation is curved, perform control to set the charge / discharge time in the reference measurement environment or the measurement range of the voltage. The capacitor degradation diagnosis device according to claim 1 or 2, characterized in that.

8. The physical quantity of the capacitor is voltage, current, or temperature, the charge / discharge characteristic of the capacitor is the charge / discharge voltage characteristic of the capacitor, and the electrical characteristic of the capacitor is capacitance, internal resistance, or voltage change. The capacitor degradation diagnosis device according to claim 1 or 2, characterized in that.

9. The capacitor is an electric double layer capacitor or a lithium ion capacitor. The capacitor degradation diagnosis device according to claim 1 or 2, characterized in that.

10. The degradation diagnosis unit includes a monitor or a recording device that displays the capacitance or the internal resistance calculated from the measured physical quantity of the capacitor. The capacitor degradation diagnosis device according to claim 2, characterized in that.

11. The reference measurement environment is an environment in which the capacitance retention rate is 100% when based on the initial capacitance of the capacitor at the time of use, The non-reference measurement environment is an environment in which the capacitance retention rate of the capacitor is 99% or less when the capacitance retention rate of a new capacitor is set to 100%, and the capacitor degradation diagnosis device according to claim 1 or 2, characterized in that.

12. The reference measurement environment is a room temperature environment, The non-reference measurement environment is an environment in which the temperature of the capacitor is less than 25°C, and the capacitor degradation diagnosis device according to claim 1 or 2, characterized in that.

13. A method for diagnosing degradation of a capacitor using the capacitor degradation diagnosis device according to claim 1, The measurement range of the charge and discharge characteristics of the capacitor in the non-reference measurement environment is made wider than the measurement range of the charge and discharge characteristics of the capacitor in the reference measurement environment, A method for diagnosing degradation of a capacitor, characterized in that.

14. The measurement range of the charge and discharge characteristics is the measurement range of the time variation of the voltage during charge and discharge. The measurement range of the time variation of the voltage during charge and discharge of the capacitor in the non-reference measurement environment and the measurement range of the time variation of the voltage during charge and discharge of the capacitor in the reference measurement environment of the capacitor are made to coincide, The charge and discharge time of the capacitor in the non-reference measurement environment is made longer than the charge and discharge time of the capacitor in the reference measurement environment of the capacitor, A method for diagnosing degradation of a capacitor according to claim 13, characterized in that.

15. The measurement range of the charge and discharge characteristics is the measurement range of the amount of change in the voltage during charge and discharge, The time variation amount of the portion where the electrical characteristics during charge and discharge of the capacitor in the non-reference measurement environment are linear and the time variation amount of the portion where the electrical characteristics during charge and discharge of the capacitor in the reference measurement environment are linear are made to coincide, The length of the portion where the electrical characteristics during charge and discharge of the capacitor in the reference measurement environment are linear is made larger than the length of the portion where the electrical characteristics during charge and discharge of the capacitor in the non-reference measurement environment are linear, A method for diagnosing degradation of a capacitor according to claim 13, characterized in that.

16. The charge and discharge time of the capacitor in the non-reference measurement environment is made longer than the charge and discharge time of the capacitor in the reference measurement environment until the value obtained by differentiating the voltage fluctuation during charge and discharge of the capacitor with respect to the charge and discharge time becomes a constant value. The method for diagnosing deterioration of a capacitor according to claim 13, characterized in that...

17. A method for diagnosing deterioration of a capacitor using the capacitor deterioration diagnosis device according to claim 5, wherein... the measurement range of the charge-discharge characteristics of the capacitor in a non-reference measurement environment of the capacitor is made wider than the measurement range of the charge-discharge characteristics of the capacitor in a reference measurement environment of the capacitor. A method for diagnosing deterioration of a capacitor, characterized in that...

18. The measurement range of the charge-discharge characteristics is the measurement range of the time variation of the voltage during charge and discharge. The measurement range of the time variation of the voltage during charge and discharge of the capacitor in the non-reference measurement environment of the capacitor and the measurement range of the time variation of the voltage during charge and discharge of the capacitor in the reference measurement environment of the capacitor are made to coincide. The charge-discharge time of the capacitor in a non-reference measurement environment of the capacitor is made longer than the charge-discharge time of the capacitor in a reference measurement environment of the capacitor. The method for diagnosing deterioration of a capacitor according to claim 17, characterized in that...

19. The measurement range of the charge-discharge characteristics is the measurement range of the amount of change in voltage during charge and discharge. The time variation amount of the portion where the electrical characteristics during charge and discharge of the capacitor in the non-reference measurement environment of the capacitor are linear and the time variation amount of the portion where the electrical characteristics during charge and discharge of the capacitor in the reference measurement environment of the capacitor are linear are made to coincide. The length of the portion where the electrical characteristics during charge and discharge of the capacitor in the reference measurement environment of the capacitor are linear is made larger than the length of the portion where the electrical characteristics during charge and discharge of the capacitor in the non-reference measurement environment of the capacitor are linear. The method for diagnosing deterioration of a capacitor according to claim 17, characterized in that...

20. The charge-discharge time of the capacitor in a non-reference measurement environment of the capacitor is made longer than the charge-discharge time of the capacitor in a reference measurement environment of the capacitor by the time until the value obtained by differentiating the voltage fluctuation during charge and discharge of the capacitor with respect to the charge-discharge time becomes a constant value. The method for diagnosing deterioration of a capacitor according to claim 17, characterized in that...