Capacitor degradation diagnostic device and degradation diagnostic method

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

[Technical Field]

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

[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 lose capacitance and their internal resistance increases over time. 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 that determines the slope of the portion of the voltage waveform during discharge where a linear change holds. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2010-139304 A [Non-patent literature]

[0005] [Non-Patent Document 1] Kinoshita, "Electric Double Layer Capacitor <edlc>Characteristics and Effective Use of ", First Edition, Nikkan Kogyo Shimbun, March 30, 2010, pp.38-44 [Non-patent document 2] T.Funaki,"Evaluating Energy Storage Efficiency by Modeling the Voltage and Temperature Dependency in EDLC Electrical Characteristics",IEEE TRANSACTIOINS ON POWER ELECTRONICS,VOL.25,NO.5,MAY 2010 Summary of the Invention [Problem to be solved by the invention]

[0006] However, Patent Document 1 requires a certain period of pause at the end of discharge, making it unsuitable for devices that cannot accommodate 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. [Means for solving the problem]

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

[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 capacitor temperature changes to 25°C or below. [Brief explanation of the drawings]

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

[0011] The capacitor degradation diagnostic device according to the first embodiment will be described below with reference to the drawings.

[0012] Embodiment 1 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 diagnostic device 1 (see the dotted-line frame (bottom)) includes an information acquisition unit 3, a control device 4, and a charge / discharge circuit 5, and performs degradation diagnosis of an electric double layer capacitor 2 (EDLC2) by a degradation diagnostic unit 6 using the electrical characteristics (such as voltage) of the capacitor as an index. Note that the diagnostic results may also be used to predict a lifespan.

[0014] The EDLC2 can be of various shapes, such as cylindrical, rectangular, or laminated. It can also be configured as a module with multiple EDLCs connected in series or parallel. It is also possible to use a lithium ion capacitor instead of an 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] Fig. 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 voltage, current, and temperature data of the EDLC 2 output from the information acquisition unit 3 is input to the input unit 41. 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] FIG. 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. Data such as the voltage, current, and temperature of the EDLC 2 output from the information acquisition unit 3 is input to the input unit 61. Based on the data from the input unit 61, the calculation unit 62 calculates the capacitance or internal resistance (value). 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 change in the capacitance or internal resistance value due to degradation, and output the result to a monitor, a recording device, etc.

[0018] Here, we will explain a general method for calculating the capacitance of an EDLC. 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). Before degradation (when not degraded) refers to a new state in which the capacitance has not decreased. In other words, when the capacitance at the beginning of use (hereinafter simply referred to as the initial state) is used as the reference, this is a state in which the capacity retention rate is 100%. Furthermore, the room temperature environment refers to a temperature around 25°C, but a high temperature environment (25°C or higher) can 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 EDLCs changes significantly, with the internal resistance increasing in a curved fashion as the temperature drops, and that this influences the terminal voltage of an EDLC at -10°C when discharging lower and the terminal voltage when charging higher. It is also important to note that capacitance tends to decrease, particularly when the voltage drops below the rated voltage (see, for example, Non-Patent Documents 1 and 2).

[0020] As shown in Figure 5, the initial voltage of the EDLC is V0. When discharging occurs at a current value I from time t1 to t2, the voltage of the EDLC changes from V1 to V2. 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, so in Figure 5, it is calculated using ΔV, the difference between V1 and V2, and Δt, the difference between t1 and t2, using the following formula (1):

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

[0022] Figure 6 shows the voltage fluctuation and current waveform of an EDLC during degradation or in a low-temperature environment. Degradation refers to a state in which the capacitance has decreased since a new product and the current capacity retention rate is lower than the initial capacity retention rate. For example, when the capacity retention rate of a new product is taken as 100%, this refers to a state in which the capacity retention rate is 99% or less (this value will be referred to as the threshold value hereinafter). As mentioned above, a low-temperature environment refers to a temperature below 25°C, more preferably 0°C or less.

[0023] When an EDLC deteriorates (in a low-temperature environment), the voltage fluctuations at the beginning of discharge become 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 described above in the voltage fluctuations during discharge decreases (ΔV > ΔVa, Δt > Δta). Therefore, the range of data used to calculate the capacitance narrows, increasing the impact 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), it is possible to maintain diagnostic accuracy similar to that in the reference measurement environment by controlling the discharge time. In other words, 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 it is ultimately desirable to control the time so that Δta = Δt.

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

[0027] FIG. 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 period 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] In FIG. 7, the control is based on time, but it may also be based on voltage. When controlling by voltage, the discharge cut-off voltage should be 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 lookup table or the like, and may be referenced each time for control.

[0030] As described above, the capacitor degradation diagnostic device of the first embodiment can obtain electrical characteristics (voltage change over time, voltage fluctuation) similar to those in the reference measurement environment by lengthening the discharge time and widening the voltage range in the non-reference measurement environment. Pressure It is possible to ensure a time during which the voltage change (also called time variation) becomes linear. The magnitude of the voltage change over a certain time range is also called the amount of time change. As a result, the impact on measurement variation in a non-reference measurement environment can be reduced and can be made to the same level as measurement variation in a reference measurement environment, making it possible to maintain diagnostic accuracy (for example, the accuracy of the error included in the calculation of capacitance).

[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 (which are devices that calculate capacitance from the slope of voltage fluctuations during charging and discharging), as described above. Note that while the first embodiment has been mainly described with respect to the case of discharging a capacitor, the device can also be implemented in the case of charging. That is, in capacitor degradation diagnosis, particular attention is paid to the characteristics during discharging, in which voltage changes significantly over time, or the characteristics during charging, and whether or not these characteristics have deteriorated is often used as a criterion for judgment. Therefore, in the following, when describing both the characteristics during discharge and the characteristics during charge, they are referred to as charge / discharge characteristics. That is, the charge / discharge characteristics refer to electrical characteristics such as voltage that change over time during charging or discharging. These charge / discharge characteristics change significantly during charging or discharging.

[0032] Embodiment 2 A method for controlling the charge and discharge time will be described in this embodiment 2. The overall configuration of the degradation diagnosis device used here is the same as in the embodiment 1, so a description thereof will be omitted. As described in the first embodiment, in a non-standard measurement environment, the voltage fluctuation of an EDLC becomes curved rather than linear immediately after the start of charging and discharging. Therefore, using the voltage measured by the information acquisition unit 3, the control device 4 calculates dV / dt, which is the time derivative of the voltage.

[0033] FIG. 8 shows the slope dV / dt obtained from the voltage fluctuation (also called voltage change) during discharge. In the standard measurement environment, the dashed line C in the figure 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 small (negative) constant value S compared to 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 discharge starts (see Fig. 6). Therefore, the solid line C in Fig. 8 b As shown in Figure 8, dV / dt fluctuates for a certain period of time (the time during which dV / dt fluctuates is called t b ), and then a constant value S b Therefore, the time it takes for dV / dt to reach a constant value, t b The discharge time is extended by the time C b (See the thick solid line, which is the extension.) This makes the time of the linear portion in the reference measurement environment equal to the time of the linear portion in the non-reference measurement environment.

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

[0036] In addition, in the above, if it is difficult to calculate dV / dt instantly during discharge due to the equipment used 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). This makes it possible to make the effect of measurement variation the same as in the reference measurement environment (suppress it), and maintain a consistent accuracy in deterioration diagnosis. In the second embodiment, the explanation has been limited to the contents relating to the discharge time, but the same explanation can be given not only to the discharge time but also to the contents relating to the charge time, and the same effect can be obtained.

[0038] As explained above, by setting a longer charge / discharge time in the non-reference measurement environment, a time for linear change can be ensured in the non-reference measurement environment as well, similar to the reference measurement environment. As a result, the influence of measurement variations can be suppressed in the non-reference measurement environment as well, similar to the reference measurement environment, and diagnostic accuracy can be maintained (the error included in the capacitance calculation can be suppressed to the same or less).

[0039] Embodiment 3 In the third embodiment, a method of controlling time or voltage different from that in the second embodiment will be described.

[0040] FIG. 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 measuring the degradation diagnostic data of the EDLC, 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] Figure 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 Figure 10, the relationship between t b By recording the past b From the transition of t b can be predicted. In Figure 10, the time of use or the amount of deterioration is b Taking advantage of 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, 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 calculates t b The predicted t b Discharged using the measured t b If there is a difference, compare it with the actual measured value. b Record the time and the next time b By using it to predict the temperature, measurement accuracy can be improved.

[0044] Figure 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, you can use a quadratic function or other methods to predict. For example, all the t b Instead of using the data from 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 this data to control the discharge time, it is possible to simplify the calculation process. In other words, by using the data on the time when the voltage change measured so far is on the curve 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 equally applicable to the case of controlling voltage.

[0046] Embodiment 4 In the fourth embodiment, the deterioration diagnosis device does not control the charge / discharge time or voltage range in deterioration diagnosis. Also, the time of the curved portion in a non-reference measurement environment (after deterioration or in a low-temperature environment) is t b 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, so a detailed description will be omitted here.

[0047] 12 is a diagram showing discharge characteristics in a standard measurement environment. In the first to third embodiments, the discharge time in the standard measurement environment (before deterioration or at room temperature) is Δt. In the present embodiment, however, t b 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 portion is Δt+t b However, the capacitance is calculated using data for Δt seconds. 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] Note that it is also possible to control by voltage instead of time, as in the first to third embodiments. In this case, the discharge cut-off voltage may be changed from V2 to V2-Vb (=V2-(V1-Va1)). Although the above description has been given of specific implementation details for discharging, the specific implementation details are similar for charging. That is, 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 to the processor 101 from the auxiliary storage device 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 the present application describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to application to a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless variations not illustrated are conceivable within the scope of the technology disclosed in the present specification, including, for example, cases where at least one component is modified, added, or omitted, and cases where at least one component is extracted and combined with components of another embodiment.

[0054] Specifically, for example, in the above explanation, as shown in Figure 1, the information acquisition unit 3 and the charge / discharge circuit 5 constitute part of the deterioration diagnosis device 1, but this is not limited to this. As shown in Figure 14, the information acquisition unit 3 and the charge / discharge circuit 5 are not components of the deterioration diagnosis device 1, and the deterioration diagnosis device 1b may be constituted by only the deterioration diagnosis unit 6 and the control device 4 (see the dotted 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, which acquires 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. [Explanation of symbols]

[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 Charge / discharge control unit, 43 Output unit, 5 Charge / discharge circuit, 6 Degradation diagnosis unit, 61 Input unit, 62 Calculation unit, 63 Output unit, 7 Memory unit, 100, 100a Hardware, 101 Processor, 102 Memory device< / edlc>

Claims

1. an information acquisition unit that measures and acquires physical quantities of the capacitor; a charge / discharge circuit that charges and discharges the capacitor; a control device that controls the charge / discharge circuit based on the physical quantity of the capacitor acquired by the information acquisition unit so that a measurement range of charge / discharge characteristics, which are electrical characteristics that occur over time during charging or discharging, in a non-standard measurement environment of the capacitor is wider than a measurement range of charge / discharge characteristics in a standard measurement environment of the capacitor; Equipped with The deterioration of the capacitor is diagnosed based on the difference between the electrical characteristics of the capacitor at the beginning of use and the electrical characteristics of the capacitor after the lapse of time when the capacitor is charged and discharged. A capacitor deterioration diagnostic device characterized by:

2. a degradation diagnosis unit that diagnoses performance degradation of the capacitor using the electrical characteristics of the capacitor as an index; the degradation diagnosis unit calculates electrical characteristics of the capacitor and amounts of change in the electrical characteristics based on the physical quantities obtained from the information acquisition unit, and diagnoses degradation of the capacitor based on whether or not the calculated amounts of change in the electrical characteristics of the capacitor from values ​​at the beginning of use exceed a predetermined threshold.

2. The capacitor deterioration diagnostic device according to claim 1.

3. the measurement range of the charge / discharge characteristics is a measurement range of time fluctuation of voltage during charge / discharge, The control device so that the range of time fluctuation of the voltage during charging and discharging in the non-reference measurement environment of the capacitor coincides with the range of time fluctuation of the voltage during charging and discharging in the reference measurement environment of the capacitor, controlling the charge / discharge circuit to make the charge / discharge time of the capacitor in the non-standard measurement environment longer than the charge / discharge time of the capacitor in the standard measurement environment; 3. The capacitor deterioration diagnostic device according to claim 1 or 2.

4. the measurement range of the charge / discharge characteristics is a measurement range of a change in voltage during charge / discharge, The control device so that the amount of change over time of the linear portion of the electrical characteristics during charging and discharging in the non-standard measurement environment of the capacitor coincides with the amount of change over time of the linear portion of the electrical characteristics during charging and discharging in the standard measurement environment of the capacitor, controlling the charge / discharge circuit so that the length of a portion where the electrical characteristics of the capacitor during charging / discharging in the reference measurement environment are linear is longer than the length of a portion where the electrical characteristics of the capacitor during charging / discharging in the non-reference measurement environment are linear; 3. The capacitor deterioration diagnostic device according to claim 1 or 2.

5. The control device The charge / discharge circuit is controlled to make the charge / discharge time of the capacitor in the non-standard measurement environment longer than the charge / discharge time of the capacitor in the standard measurement environment by the time from the start of charging / discharging until a value obtained by differentiating a voltage fluctuation during charging / discharging of the capacitor with respect to the charge / discharge time becomes a constant value.

3. The capacitor deterioration diagnostic device according to claim 1 or 2.

6. a storage unit that records voltage fluctuations during charging and discharging of the capacitor; The control device Control is performed to set the charge / discharge time for a new measurement or the charge / discharge time in a low-temperature environment for the first measurement, based on data of the portion where the measured time variation of the voltage is curved, for the charge / discharge circuit.

3. The capacitor deterioration diagnostic device according to claim 1 or 2.

7. The control device When the time period during which the voltage fluctuation of the capacitor when being charged or discharged in a non-standard measurement environment is curved or the amount of voltage change is known, the charge / discharge circuit performs control to set the charge / discharge time or the voltage measurement range in the standard measurement environment in advance, taking into consideration the time period during which the voltage fluctuation is curved or the amount of voltage change in the curved portion of the voltage fluctuation.

3. The capacitor deterioration diagnostic device according to claim 1 or 2.

8. 3. The capacitor degradation diagnosis device according to claim 1, wherein the physical quantities of the capacitor are voltage, current, and temperature, the charge / discharge characteristics of the capacitor are charge / discharge voltage characteristics of the capacitor, and the electrical characteristics of the capacitor are capacitance, internal resistance, or voltage change.

9. 3. The capacitor deterioration diagnostic device according to claim 1, wherein the capacitor is an electric double layer capacitor or a lithium ion capacitor.

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.

3. The capacitor deterioration diagnostic device according to claim 2.

11. The reference measurement environment is an environment in which the capacitance retention rate of the capacitor is 100% when the capacitance at the initial stage of use is used as a reference, 3. The capacitor degradation diagnosis device according to claim 1, wherein the non-standard measurement environment is an environment in which the capacity retention rate of the capacitor is 99% or less when the capacity retention rate of a new capacitor is 100%.

12. The reference measurement environment is a room temperature environment, 3. The capacitor degradation diagnostic device according to claim 1, wherein the non-reference measurement environment is an environment in which the temperature of the capacitor is below 25°C.

13. A capacitor degradation diagnosis method using the capacitor degradation diagnosis device according to claim 1, comprising: The measurement range of the charge / discharge characteristics of the capacitor in the non-standard measurement environment is made wider than the measurement range of the charge / discharge characteristics of the capacitor in the standard measurement environment. A method for diagnosing deterioration of a capacitor, comprising:

14. The measurement range of the charge / discharge characteristics is a measurement range of a time variation of a voltage during charge / discharge, and the measurement range of the time variation of the voltage during charge / discharge in the non-standard measurement environment of the capacitor is set to coincide with the measurement range of the time variation of the voltage during charge / discharge in the standard measurement environment of the capacitor. The charge / discharge time of the capacitor in the non-standard measurement environment is made longer than the charge / discharge time of the capacitor in the standard measurement environment.

14. The method for diagnosing deterioration of a capacitor according to claim 13.

15. the measurement range of the charge / discharge characteristics is a measurement range of a change in voltage during charge / discharge, so that the amount of change over time of the linear portion of the electrical characteristics during charging and discharging in the non-standard measurement environment of the capacitor coincides with the amount of change over time of the linear portion of the electrical characteristics during charging and discharging in the standard measurement environment of the capacitor, The length of the portion where the electrical characteristics of the capacitor during charging and discharging in the reference measurement environment are linear is made longer than the length of the portion where the electrical characteristics of the capacitor during charging and discharging in the non-reference measurement environment are linear.

14. The method for diagnosing deterioration of a capacitor according to claim 13.

16. The charge / discharge time of the capacitor in the non-standard measurement environment is made longer than the charge / discharge time of the capacitor in the standard measurement environment by the time until a value obtained by differentiating the voltage fluctuation during charge / discharge of the capacitor with respect to the charge / discharge time becomes a constant value.

14. The method for diagnosing deterioration of a capacitor according to claim 13.

17. A capacitor degradation diagnosis method using the capacitor degradation diagnosis device according to claim 5, comprising: The measurement range of the charge / discharge characteristics of the capacitor in the non-standard measurement environment is made wider than the measurement range of the charge / discharge characteristics of the capacitor in the standard measurement environment. A method for diagnosing deterioration of a capacitor, comprising:

18. The measurement range of the charge / discharge characteristics is a measurement range of a time variation of a voltage during charge / discharge, and the measurement range of the time variation of the voltage during charge / discharge in the non-standard measurement environment of the capacitor is set to coincide with the measurement range of the time variation of the voltage during charge / discharge in the standard measurement environment of the capacitor. The charge / discharge time of the capacitor in the non-standard measurement environment is made longer than the charge / discharge time of the capacitor in the standard measurement environment.

18. The method for diagnosing deterioration of a capacitor according to claim 17.

19. the measurement range of the charge / discharge characteristics is a measurement range of a change in voltage during charge / discharge, so that the amount of change over time of the linear portion of the electrical characteristics during charging and discharging in the non-standard measurement environment of the capacitor coincides with the amount of change over time of the linear portion of the electrical characteristics during charging and discharging in the standard measurement environment of the capacitor, The length of the portion where the electrical characteristics of the capacitor during charging and discharging in the reference measurement environment are linear is made longer than the length of the portion where the electrical characteristics of the capacitor during charging and discharging in the non-reference measurement environment are linear.

18. The method for diagnosing deterioration of a capacitor according to claim 17.

20. The charge / discharge time of the capacitor in the non-standard measurement environment is made longer than the charge / discharge time of the capacitor in the standard measurement environment by the time until a value obtained by differentiating the voltage fluctuation during charge / discharge of the capacitor with respect to the charge / discharge time becomes a constant value.

18. The method for diagnosing deterioration of a capacitor according to claim 17.

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