Abnormality detection device, abnormality detection method, and computer program

Abstract

To improve detection accuracy of abnormality of a detection object without causing an abnormality due to abnormality detection on the detection object while considerably shortening abnormality determination time.SOLUTION: An abnormality detection device for detecting abnormality in a detection object including an electrochemical device comprises: a voltage application part which applies voltage to the detection object; a current acquisition part which acquires the response current of the detection object to which voltage is applied; and a calculation part, which calculates the amount of electricity by integrating the acquired response current for a predetermined amount of time. The voltage application part applies the sum of a DC voltage and an AC voltage to the detection object.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an abnormality detection device, an abnormality detection method, and a computer program. [Background technology]

[0002] There is known a technique for detecting an abnormality in the internal state of an electrochemical device such as a secondary battery (see, for example, Patent Document 1). In the state detection method described in Patent Document 1, basic data is obtained, which is data on the battery voltage and the amount of stored or discharged electricity when a normal secondary battery is charged and discharged at various temperatures and currents. The voltage value or the voltage value and current value of the secondary battery to be detected for an abnormality are measured, and the measured data is compared with the basic data to detect an abnormality in the internal state of the secondary battery to be detected. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5074648 Summary of the Invention [Problem to be solved by the invention]

[0004] Electrochemical devices such as secondary batteries such as lithium ion batteries and primary batteries, which are the subject of abnormality detection described in Patent Document 1, have electromotive force even when no electrical energy is input. Therefore, when an abnormality such as a short circuit occurs inside an electrochemical device having electromotive force, a closed circuit occurs at the short circuit point, causing a change in the electromotive force. Therefore, it is relatively easy to detect a short circuit in an electrochemical device having electromotive force.

[0005] On the other hand, when an electrochemical device such as a water electrolysis cell is supplied with electrical energy from the outside, an electrochemical reaction occurs and generates an electromotive force. That is, in an electrochemical device such as a water electrolysis cell, the time during which an electromotive force is generated is limited to the time during which electrical energy is supplied. Therefore, in a state in which electrical energy is not being supplied to the electrochemical device, such as immediately after manufacture or during downtime, an abnormality detection using an electromotive force does not function.

[0006] In the aging process, which is a short circuit detection of an electrochemical device by a change in electromotive force, the electrochemical device to be detected is left in a certain environment for at least "days", and the voltage is measured each time. By excluding solids whose measured voltages are outside the population, the occurrence of accidents in electrochemical devices in the market is suppressed. The accuracy of detecting an abnormality improves the longer the time left until an abnormality is judged, that is, the aging time. However, since the cost required for aging increases if the aging time, which is left at least in "days", is longer, the relationship between the aging time and the detection accuracy is a trade-off with cost. In addition, the combination of the aging process and voltage measurement cannot be applied to electrochemical devices that do not have an electromotive force in the first place. Therefore, the polarization method, in which a voltage is applied to the detection target and the response current is measured, can be applied to electrochemical devices that do not have an electromotive force. Regarding the time required for an abnormality judgment, the polarization method measures the response current to the application of a voltage, and therefore can be significantly shorter than the aging method, which uses leaving it for "days" and the change in voltage over time. This polarization method can also be applied to electrochemical devices that have electromotive force, but the polarization method may cause another problem that does not occur in the aging method. That is, in DC voltage polarization, an inrush current immediately after polarization may cause another abnormality such as a breakdown in the detection target.

[0007] The present invention is intended to solve at least part of the above-mentioned problems, and aims to improve the detection accuracy of abnormalities in a detection target without causing an abnormality in the detection target due to abnormality detection, while significantly shortening the time until an abnormality is determined. [Means for solving the problem]

[0008] The present invention is intended to solve at least a part of the above-mentioned problems, and can be realized in the following forms.

[0009] (1) According to one aspect of the present invention, there is provided an abnormality detection device for detecting an abnormality in a detection target including an electrochemical device. The abnormality detection device includes a voltage application unit that applies a voltage to the detection target, a current acquisition unit that acquires a response current of the detection target to which the voltage has been applied, and a calculation unit that calculates an electric quantity by integrating the acquired response current for a predetermined time, and the voltage application unit applies a voltage obtained by adding a DC voltage and an AC voltage to the detection target.

[0010] According to this configuration, a voltage obtained by adding a DC voltage and an AC voltage is applied to the detection target in which an abnormality is detected. The amount of electricity obtained by integrating the response current of the detection target when the voltage is applied is used to detect an abnormality in the detection target. Here, in a conventional technique different from this configuration, an abnormality such as a short circuit occurring in the detection target is detected by integrating the response current of DC polarization in which only a DC voltage is applied to the detection target. However, in the application of only a DC voltage, i.e., simple DC polarization, an inrush current may cause another abnormality such as a failure in the detection target. On the other hand, in the conventional technique in which only an AC voltage is applied to the detection target, a voltage below zero volts may be applied to the detection target, causing damage to the detection target and causing another abnormality such as a failure. In contrast, in this configuration, a voltage obtained by adding a DC voltage and an AC voltage is applied to the detection target, so that it is possible to suppress the occurrence of an abnormality in the detection target. In other words, the polarization method significantly shortens the time until an abnormality is determined compared to the aging method without causing an abnormality in the detection target due to the abnormality detection, and the detection accuracy of the abnormality of the detection target is improved.

[0011] (2) The abnormality detection device of the above aspect may further include a temperature acquisition unit that acquires a temperature of the detection object, and a determination unit that determines whether or not an abnormality has occurred in the detection object by comparing the electrical quantity calculated by the calculation unit with a threshold value that is set in advance according to the temperature of the detection object. According to this configuration, an abnormality occurring in the detection object is easily determined by comparing the integral value of the response current with a threshold value that is set in advance as a normal value. Since the electrical resistance of the detection object is affected by temperature, the detection accuracy of the abnormality of the detection object is further improved by setting different threshold values ​​according to the temperature of the detection object.

[0012] (3) In the abnormality detection device according to the above aspect, the voltage application unit may set a voltage value of the DC voltage and a maximum voltage value of the AC voltage to be the same. According to this configuration, the voltage value of the DC voltage and the maximum voltage value of the AC voltage are set to be the same, and thus the minimum voltage value of the sum of the DC voltage and the AC voltage is set to zero V. As a result, a voltage below zero V is not applied to the detection object, and an abnormality in the detection object is determined without applying a voltage higher than necessary.

[0013] (4) In the abnormality detection device of the above aspect, the voltage application unit may set the frequency of the AC voltage to 10 Hz or more and 10 kHz or less. According to this configuration, the frequency is not too high, so that integral calculation of the response current is easy, and since the frequency is not too low, the time for applying voltage to detect an abnormality in the detection target can be reduced.

[0014] The present invention can be realized in various forms, for example, in the form of an anomaly detection device, an inspection device, a system including these devices, a control method for these devices and systems, a computer program executed in these devices and systems, a server device for distributing the computer program, a non-transitory storage medium on which the computer program is stored, etc. [Brief description of the drawings]

[0015] [Figure 1] 1 is a schematic block diagram of an abnormality detection device according to an embodiment of the present invention; [Diagram 2] FIG. 1 is a schematic circuit diagram of an equivalent circuit including a water electrolysis cell. [Diagram 3] FIG. 3 is a Nyquist diagram of the impedance of the equivalent circuit shown in FIG. 2. [Figure 4] This is a vector diagram in a Bode diagram of the impedance of an equivalent circuit. [Diagram 5] FIG. 1 is a phase diagram in a Bode diagram of the impedance of an equivalent circuit. [Figure 6] 4 is a flowchart of a method for detecting an abnormality in a water electrolysis cell. [Figure 7] FIG. 4 is an explanatory diagram of voltage changes in an embodiment. [Figure 8] FIG. 11 is an explanatory diagram of a DC voltage in Comparative Example 1. [Figure 9] FIG. 11 is an explanatory diagram of a change in AC voltage in Comparative Example 2. [Figure 10] FIG. 1 is an explanatory diagram of a response current when a voltage according to an embodiment is applied to a water electrolysis cell without an abnormality. [Figure 11] FIG. 1 is an explanatory diagram of a response current when a voltage according to an embodiment is applied to a water electrolysis cell having an abnormality. [Figure 12] FIG. 2 is a graph showing the response current when a DC voltage of Comparative Example 1 is applied to a normal water electrolysis cell. [Figure 13] FIG. 1 is a graph showing a response current when a DC voltage of Comparative Example 1 is applied to a water electrolysis cell having an abnormality. [Figure 14] FIG. 13 is a graph showing the response current when an AC voltage of Comparative Example 2 is applied to a normal water electrolysis cell. [Figure 15] FIG. 13 is a graph showing the response current when the AC voltage of Comparative Example 2 is applied to a water electrolysis cell having an abnormality. [Figure 16] FIG. 1 is a diagram illustrating the amount of electricity when a voltage according to an embodiment is applied to a water electrolysis cell without a defect. [Figure 17] FIG. 1 is an explanatory diagram of the amount of electricity when a voltage according to an embodiment is applied to a water electrolysis cell having an abnormality. [Figure 18] FIG. 2 is a diagram illustrating the quantity of electricity when a DC voltage of Comparative Example 1 is applied to a normal water electrolysis cell. [Figure 19] FIG. 1 is a diagram illustrating the amount of electricity when a DC voltage of Comparative Example 1 is applied to a water electrolysis cell having an abnormality. [Figure 20] FIG. 2 is an explanatory diagram of the evaluation results of an example and comparative examples 1 and 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] <Embodiment> FIG. 1 is a schematic block diagram of an anomaly detection device 100 according to one embodiment of the present invention. In this embodiment, the anomaly detection device 100 detects an anomaly in a water electrolysis cell CL, which is a detection target. The water electrolysis cell CL generates an electromotive force when electric energy is input. The anomaly detection device 100 applies a voltage obtained by adding a DC voltage and an AC voltage to the water electrolysis cell CL and obtains a response current of the water electrolysis cell CL. The presence or absence of an anomaly in the water electrolysis cell CL is determined using an electrical quantity obtained by integrating the response current over time. In this embodiment, the voltage applied to the water electrolysis cell CL is the sum of a DC voltage and an AC voltage, which reduces the detection time and improves the detection accuracy of an anomaly in the detection target.

[0017] As shown in FIG. 1, the abnormality detection device 100 includes a DC power supply 40 that applies a DC voltage to the water electrolysis cell CL, an AC power supply 50 that applies an AC voltage to the water electrolysis cell CL, a control device 10 that controls the DC power supply 40 and the AC power supply 50, a thermometer 61 that detects the temperature of the water electrolysis cell CL, an ammeter 62 that detects the current flowing through the water electrolysis cell CL, and a voltmeter 63 that detects the voltage applied to the water electrolysis cell CL.

[0018] When raw water is supplied to the water electrolysis cell CL and electric power is supplied to the water electrolysis cell CL, the water electrolysis cell CL undergoes a water decomposition reaction to generate hydrogen and oxygen. As shown in Fig. 1, the DC power supply 40 and the AC power supply 50 are connected in parallel to the water electrolysis cell CL. Therefore, the voltage applied to the water electrolysis cell CL is the sum of the DC voltage of the DC power supply 40 and the AC voltage of the AC power supply 50.

[0019] The control device 10 is configured, for example, by a personal computer. The control device 10 includes a CPU (Central Processing Unit) 20 and a storage unit 30. The storage unit 30 includes a hard disk drive (HDD: Hard Disk Drive) and the like. The storage unit 30 includes a threshold database (threshold DB) 31 and an electric quantity database (electric quantity DB) 32.

[0020] The threshold DB 31 stores a threshold for determining whether or not an abnormality has occurred in the water electrolysis cell CL. The threshold DB 31 stores an amount of electricity (C: coulomb) obtained by integrating the response current when the water electrolysis cell CL is normal and has no abnormality, and a numerical value of a ratio used as a threshold. The amount of electricity and the ratio stored in the threshold DB 31 are numerical values ​​that differ in advance depending on the temperature of the water electrolysis cell CL. The amount of electricity DB 32 stores an amount of electricity obtained by time-integrating the response current calculated when an abnormality is detected in the water electrolysis cell CL. The threshold values ​​stored in the threshold DB 31 and the amounts of electricity stored in the amount of electricity DB 32 will be described in detail later.

[0021] The CPU 20 is connected to a read only memory (ROM) and a random access memory (RAM), not shown, and controls each part of the abnormality detection device 100 by expanding a computer program stored in the ROM into the RAM and executing it. In addition, the CPU 20 also functions as a voltage control part 21, a temperature acquisition part 22, a current acquisition part 23, a calculation part 24, and a determination part 25.

[0022] The voltage control unit 21 controls the DC power supply 40 and the AC power supply 50 to set the voltage to be applied to the water electrolysis cell CL. In this embodiment, the voltage control unit 21 sets the DC voltage applied by the DC power supply 40 to the same value as the maximum AC voltage applied by the AC power supply 50. The voltage control unit 21 applies to the water electrolysis cell CL a voltage obtained by adding the DC voltage generated by the DC power supply 40 and the AC voltage generated by the AC power supply 50. The voltage control unit 21 also acquires the voltage applied to the water electrolysis cell CL detected by the voltmeter 63. The voltage control unit 21 sets a voltage value at which polarization occurs in the water electrolysis cell CL as the voltage to be applied to the water electrolysis cell CL. The set voltage value does not need to reach an electromotive force at which an electrochemical reaction occurs (for example, 0.06 V). The voltage control unit 21, the DC power supply 40, and the AC power supply 50 function as a voltage application unit that applies a voltage to the water electrolysis cell CL to be detected.

[0023] The temperature acquisition unit 22 acquires the temperature of the water electrolysis cell CL detected by the thermometer 61. The acquired temperature is used to determine whether or not there is an abnormality in the water electrolysis cell CL. The current acquisition unit 23 acquires the response current flowing through the water electrolysis cell CL detected by the ammeter 62. The calculation unit 24 calculates the amount of electricity by integrating the response current acquired by the current acquisition unit 23 over a predetermined time period. In this embodiment, the predetermined time period is set in advance.

[0024] The determination unit 25 determines whether or not an abnormality has occurred in the water electrolysis cell CL. The determination unit 25 applies a predetermined voltage to the water electrolysis cell CL, and compares the voltage detected by the voltmeter 63 with the threshold stored in the threshold DB 31 to identify the detection target in which an obvious abnormality has occurred. The determination unit 25 also determines whether or not an abnormality such as a short circuit has occurred in the detection target by comparing an amount of electricity obtained by integrating the response current calculated by the calculation unit 24 with the threshold stored in the threshold DB 31. The threshold amount of electricity is set as the amount of electricity of the water electrolysis cell CL in which no abnormality has occurred, depending on the temperature of the water electrolysis cell CL. In the present embodiment, if the ratio of the difference between the amount of electricity calculated by the calculation unit 24 and the amount of electricity of the water electrolysis cell CL in which no abnormality has occurred (normal) divided by the amount of electricity of the normal water electrolysis cell CL is equal to or smaller than a threshold (e.g., 0.8%) set as a numerical value, it is determined that there is no abnormality. On the other hand, if the calculated ratio is greater than the threshold, it is determined that there is an abnormality in the water electrolysis cell CL in which the detection target has occurred.

[0025] FIG. 2 is a schematic circuit diagram of an equivalent circuit including a water electrolysis cell CL. The power source PW is a power source combining a DC power source 40 and an AC power source 50. The resistance R0 is an electron transfer resistance (e.g., 0.1 Ω) generated by the electrolyte membrane of the water electrolysis cell CL. The resistance R1 connected in series with the resistance R0 is a reaction resistance (e.g., 0.5 Ω). The electric capacitance C1 connected in parallel with the resistance R1 is an electric capacitance (e.g., 0.2 mF) generated by the generation of an electric double layer. The resistance R2 connected in parallel with the resistance R0 and the like is a resistance generated by the occurrence of an abnormality such as an internal short circuit. In this embodiment, the resistance R2 is 50 Ω when an internal short circuit occurs as an abnormality, and is 5.0×10 12 Ω is set.

[0026] FIG. 3 is a Nyquist diagram of the impedance of the equivalent circuit shown in FIG. 2. In FIG. 3, the resistance R2 that is judged to be normal is 5.0×10 12The impedance when the resistor R2 is 50 Ω is shown by the solid curve C01. On the other hand, the impedance when the resistor R2 is determined to have an abnormality is shown by the dashed curve C11. As shown in Fig. 3, the difference between the impedance represented by the curve C01 showing no abnormality and the impedance represented by the curve C11 showing an abnormality is very small.

[0027] 4 and 5 are Bode plots of each component of the impedance of the equivalent circuit. In FIG. 4, the horizontal axis shows the vector change in impedance that changes according to the frequency of the applied AC power supply 50. In FIG. 5, the horizontal axis shows the phase difference θ that changes according to the frequency of the applied AC power supply 50. In each of FIGS. 4 and 5, the resistance R2 that is determined to be normal is 5.0×10 12 The solid curves C02 and C03 show the impedance and phase difference θ when the resistance R2, which is determined to be abnormal, is 50 Ω. On the other hand, the dashed curves C12 and C13 show the impedance and phase difference θ when the resistance R2, which is determined to be abnormal, is 50 Ω. As shown in Figures 4 and 5, the difference between the impedance and phase difference θ represented by the curves C02 and C03 indicating no abnormality and the impedance and phase difference θ represented by the curves C12 and C13 indicating an abnormality is very small. Therefore, to correctly detect an abnormality occurring in the water electrolysis cell CL, highly accurate abnormality detection is required.

[0028] FIG. 6 is a flowchart of a method for detecting an abnormality in a water electrolysis cell CL. In the abnormality detection flow of this embodiment shown in FIG. 6, first, the voltmeter 63 is connected (step S1). Next, a preset voltage is applied to the water electrolysis cell CL, and an abnormality in the water electrolysis cell CL is determined using the voltage value detected by the voltmeter 63 (step S2). In this process, a detection target having an obvious abnormality is excluded before the determination using the amount of electricity. The voltage applied to the water electrolysis cell CL and the threshold value used for the determination are stored in the threshold DB 31. In the process of step S2, if it is determined that there is an abnormality based on the detected voltage value (step S2: NO), the abnormality detection flow ends. On the other hand, if it is determined that there is no abnormality based on the detected voltage value (step S2: YES), the voltage control unit 21 sets the voltage applied to the water electrolysis cell CL (step S3). In this embodiment, the voltage control unit 21 sets the voltage value of the DC power supply 40 to 0.06 V and the maximum voltage (amplitude) of the AC power supply 50 to 0.06 V. The voltage that is set may be lower than 1.23 V at which the water electrolysis cell CL that is the detection target causes electrolysis of water.

[0029] The voltage control unit 21 performs a voltage application step of applying a set voltage to the water electrolysis cell CL (step S4). The current acquisition unit 23 performs a current acquisition step of acquiring a response current flowing through the water electrolysis cell CL via the ammeter 62 (step S5). The temperature acquisition unit 22 acquires the temperature of the water electrolysis cell CL via the thermometer 61 (step S6). The calculation unit 24 performs a calculation step of calculating the quantity of electricity by integrating the response current acquired by the current acquisition unit 23 over a predetermined time period (step S7).

[0030] Each of Figs. 7 to 9 is an explanatory diagram of the voltage applied to the water electrolysis cell CL. Fig. 7 shows the time change of a voltage AC1 in the embodiment obtained by adding up the DC voltage and the AC voltage applied to the water electrolysis cell CL. Fig. 8 shows the DC voltage DC1 (0.06 V) applied to the water electrolysis cell CL by the DC power supply 40 as Comparative Example 1. Fig. 9 shows the time change of an AC voltage AC2 applied to the water electrolysis cell CL by the AC power supply 50 as Comparative Example 2. The AC voltage AC2 shown in Fig. 9 is a sine wave having half-wave symmetry with an amplitude of 0.06 V, a minimum value of -0.06 V, and a frequency of 1 kHz. The voltage AC1 applied to the water electrolysis cell CL shown in Fig. 7 is a voltage obtained by adding up the DC voltage DC1 shown in Fig. 8 and the AC voltage AC2 shown in Fig. 9. Therefore, the voltage AC1 is a sine wave having half-wave symmetry with an amplitude of 0.06 V, a minimum value of 0 V, a frequency of 1 kHz, and a maximum value of 0.12 V.

[0031] Each of the figures from Fig. 10 to Fig. 15 is an explanatory diagram of the response current of the water electrolysis cell CL. In Figs. 10 and 11, curves C04 and C14 show the time change of the response current when a voltage AC1, which is the sum of the DC voltage and the AC voltage shown in Fig. 7, is applied. In Figs. 12 and 13, curves C05 and C15 show the time change of the response current when a DC voltage DC1 shown in Fig. 8 is applied. When a DC voltage DC1 is applied to the water electrolysis cell CL, polarization occurs, so that the response current is not constant but changes as shown by curves C05 and C15 in Figs. 2 and 13. In Figs. 14 and 15, curves C06 and C16 show the time change of the response current when an AC voltage AC2 shown in Fig. 9 is applied. The response current shown by the solid line in Figs. 10, 12, and 14 is determined to be normal when the resistance R2 is 5.0×10 12 11, 13, and 15, the response current indicated by the dashed lines is the current when the resistance R2, at which it is determined that there is an abnormality, is 50 Ω.

[0032] Each of Figs. 16 to 19 is an explanatory diagram of the quantity of electricity calculated by the calculation unit 24. In Figs. 16 and 17, straight lines L07 and L08 show the time change in the quantity of electricity obtained by integrating the response current when a voltage AC1 obtained by adding up the DC voltage and the AC voltage shown in Figs. 10 and 11 is applied. In Figs. 18 and 19, curves C08 and C18 show the time change in the quantity of electricity obtained by integrating the response current when a DC voltage DC1 shown in Figs. 12 and 13 is applied. The quantity of electricity shown by the solid line in Figs. 16 and 18 is the quantity of electricity obtained by integrating the response current when a resistance R2 of 5.0×10 12 The quantity of electricity is the quantity of electricity when the resistance R2, which is determined to be abnormal, is 50 Ω. The quantity of electricity shown by the dashed line in Figures 17 and 19 is the quantity of electricity when the resistance R2, which is determined to be abnormal, is 50 Ω. Note that the quantity of electricity of the response current when the AC voltage AC2 shown in Figures 14 and 15 is applied is zero because the current values ​​are offset by the integral value of the positive and negative currents. For this reason, the change in the quantity of electricity over time is not shown.

[0033] After the process of step S7 in FIG. 6 is performed, the determination unit 25 determines whether or not the water electrolysis cell CL has an abnormality by using the amount of electricity calculated by the calculation unit 24 (step S8). The determination unit 25 obtains a threshold value corresponding to the temperature acquired by the temperature acquisition unit 22 from the threshold DB 31. In this embodiment, the determination unit 25 obtains an amount of electricity in a normal state in which the water electrolysis cell CL has no abnormality and a threshold value for determination (e.g., 0.8%) from the threshold DB 31. The determination unit 25 calculates a ratio obtained by subtracting the amount of electricity in a normal state from the amount of electricity calculated by the calculation unit 24 and dividing the difference by the amount of electricity in the normal state. The determination unit 25 determines whether or not the calculated ratio is equal to or greater than the threshold (step S9). If the calculated ratio is equal to or greater than the threshold, the determination unit 25 determines that an abnormality has occurred in the water electrolysis cell CL to be detected. On the other hand, if the calculated ratio is less than the threshold, the determination unit 25 determines that no abnormality has occurred in the water electrolysis cell CL.

[0034] If it is determined in step S9 that the water electrolysis cell CL has an abnormality (step S9: YES), a notice is issued to stop using the water electrolysis cell CL to be detected (step S10), and the abnormality detection flow ends. The determination unit 25 may, for example, display an image on a monitor or transmit information to another device as a method for notifying the stop of use. If it is determined in step S9 that the water electrolysis cell CL has no abnormality (step S9: NO), the determination unit 25 stores the quantity of electricity calculated by the calculation unit 24 in the electricity quantity DB 32 in association with the water electrolysis cell CL to be detected (step S11), and the detection flow ends. The quantity of electricity stored in the electricity quantity DB 32 may be used for determining aging deterioration of the water electrolysis cell CL to be detected, etc.

[0035] FIG. 20 is an explanatory diagram of the effect of this embodiment. FIG. 20 shows the results of determination in an example in which the voltage AC1 obtained by adding the DC voltage DC1 and the AC voltage AC2 shown in FIG. 7 was applied as in this embodiment, in a comparative example 1 in which only the DC voltage DC1 was applied, and in a comparative example 2 in which only the AC voltage AC2 was applied. As shown in FIG. 20, in this example, the integral time of the response current, i.e., the inspection time of the water electrolysis cell CL, is 6.306 s, and the proportion used for anomaly determination is 0.9% (>0.8%). In this case, it is determined that an anomaly has occurred in the water electrolysis cell CL to be inspected. Similarly, the proportion in the comparative example 1 in which only the DC voltage DC1 was applied is 1.2% (>0.8%), and it is determined that no anomaly has occurred in the water electrolysis cell CL. In the comparative example 1, as shown in FIGS. 12 and 13, the current value decreases as the integral time (detection time) becomes longer due to the occurrence of polarization. Although the proportion in the comparative example 1 is larger than the proportion in the examples, there is a risk that the inrush current in the comparative example 1 causes an anomaly other than a short circuit. In addition, in Comparative Example 2 in which only the AC voltage AC2 is applied, the integral amount of the electric quantity is zero.

[0036] As described above, the voltage control unit 21 of the present embodiment applies a voltage obtained by adding up the DC voltage generated by the DC power supply 40 and the AC voltage generated by the AC power supply 50 to the water electrolysis cell CL to be detected. The current acquisition unit 23 acquires the response current flowing through the water electrolysis cell CL detected by the ammeter 62. The calculation unit 24 calculates the amount of electricity by integrating the response current acquired by the current acquisition unit 23 for a predetermined time. In the present embodiment, a voltage AC1 obtained by adding up the DC voltage DC1 and the AC voltage AC2 is applied to the water electrolysis cell CL in which an abnormality is detected. The amount of electricity obtained by integrating the response current of the water electrolysis cell CL during voltage application is used to detect an abnormality in the water electrolysis cell CL. Here, in Comparative Example 1 different from the present embodiment, an abnormality such as a short circuit occurring in the water electrolysis cell CL is detected by integrating the response current of DC polarization when the DC voltage DC1 is applied to the water electrolysis cell CL as shown in FIG. 9. However, in the case of application of only the DC voltage DC1, i.e., simple DC polarization, the inrush current may cause other abnormalities, such as a breakdown, in the water electrolysis cell CL. As shown in FIG. 20, the difference between the integrals of the response currents, which differ depending on whether an abnormality occurs, is small, and it takes time to detect the abnormality in order to improve the detection accuracy. On the other hand, in Comparative Example 2 in which only the AC voltage AC2 is applied to the water electrolysis cell CL, the water electrolysis cell CL may be damaged when a voltage below 0 V is applied to the water electrolysis cell CL. In Comparative Example 2, as in Comparative Example 1 in which only the DC voltage DC1 is applied, the difference between the integrals of the response currents, which differ depending on whether an abnormality occurs, is small, and it takes time to detect the abnormality in order to improve the detection accuracy. In contrast, in the present embodiment, the voltage AC1 obtained by adding the DC voltage DC1 and the AC voltage AC2 is applied to the water electrolysis cell CL, which can prevent the water electrolysis cell CL from being caused to have an abnormality. As shown in FIG. 20, the difference between the integrals of the response currents, which differ depending on whether an abnormality occurs, is large, and the abnormality in the water electrolysis cell CL can be detected more accurately in a short time. In other words, the time required for determining an abnormality is significantly shortened without causing an abnormality due to the abnormality detection, and the accuracy of detecting an abnormality in the water electrolysis cell CL is improved.

[0037] In addition, the determination unit 25 of this embodiment determines the presence or absence of an abnormality in the detection target by comparing the amount of electricity obtained by integrating the response current calculated by the calculation unit 24 with the threshold value stored in the threshold DB 31. The amount of electricity and the ratio as the threshold value stored in the threshold DB 31 are numerical values ​​that differ in advance depending on the temperature of the water electrolysis cell CL. The temperature of the water electrolysis cell CL is acquired by the temperature acquisition unit 22. In this embodiment, the integrated value of the response current is compared with a threshold value that is set in advance as a normal value, thereby easily determining whether an abnormality has occurred in the water electrolysis cell CL. Since the resistance R0 of the water electrolysis cell CL ( FIG. 2 ) is affected by temperature, the accuracy of detecting an abnormality in the water electrolysis cell CL is further improved by setting a different threshold value depending on the temperature of the water electrolysis cell CL.

[0038] Furthermore, the voltage control unit 21 of this embodiment sets the voltage value of the DC voltage applied by the DC power supply 40 to be the same as the maximum voltage value of the AC voltage applied by the AC power supply 50. In this embodiment, the voltage value of the DC voltage DC1 and the maximum voltage value of the AC voltage AC2 are set to be the same, and thus the minimum voltage value of the voltage AC1, which is the sum of the DC voltage DC1 and the AC voltage AC2, is set to 0 V. As a result, a voltage below 0 V is not applied to the water electrolysis cell CL, and a voltage higher than necessary is not applied, and an abnormality in the water electrolysis cell CL is determined.

[0039] In addition, the voltage control unit 21 of this embodiment sets the frequency of the AC voltage AC2, of the voltage AC1 applied to the water electrolysis cell CL, to 1 kHz. With this configuration, the frequency of the AC voltage AC2 is not too high, making it easy to perform integral calculation of the response current. Furthermore, because the frequency of the AC voltage AC2 is not too low, the time required for applying a voltage to detect an abnormality in the water electrolysis cell CL can be reduced.

[0040] <Modifications of the embodiment> The present invention is not limited to the above-described embodiment, and can be embodied in various forms without departing from the spirit of the present invention, for example, the following modifications are possible: In the above-described embodiment, a part of the configuration realized by hardware may be replaced by software, and conversely, a part of the configuration realized by software may be replaced by hardware.

[0041] In the above embodiment, the anomaly detection device 100 is described as an example that detects an anomaly in the water electrolysis cell CL that is the detection target. However, the anomaly detection device 100 can be modified in the range of applying a voltage AC1 obtained by adding a DC voltage DC1 and an AC voltage AC2 to the detection target and calculating an amount of electricity obtained by time-integrating a response current of the detection target. For example, the anomaly detection device 100 does not need to include the thermometer 61, the voltmeter 63, and the storage unit 30, and does not need to function as the temperature acquisition unit 22 and the determination unit 25. For example, another device that acquires the amount of electricity calculated by the calculation unit 24 from the anomaly detection device 100 may determine an anomaly in the water electrolysis cell CL. The amount of electricity at the time of determining that the water electrolysis cell CL is not abnormal may not be stored in the electricity quantity DB 32 of the storage unit 30.

[0042] In the above embodiment, the amount of electricity of the water electrolysis cell CL when no abnormality occurs, which is set according to the temperature of the water electrolysis cell CL, is used as the threshold for determining the presence or absence of an abnormality occurring in the detection target. However, the threshold may be a parameter other than the amount of electricity of the water electrolysis cell CL when no abnormality occurs, and may not be set according to the temperature of the detection target. For example, when the temperature of the storage location of the manufactured water electrolysis cells CL is kept constant and initial abnormalities of the manufactured water electrolysis cells CL are sequentially determined, the abnormality detection device 100 may determine the presence or absence of an abnormality in the water electrolysis cell CL using a threshold that is independent of the temperature of the water electrolysis cell CL. Furthermore, when abnormalities are determined for multiple water electrolysis cells CL, it may be determined that an abnormality exists in the water electrolysis cell CL for which an amount of electricity calculated for each of the multiple water electrolysis cells CL deviates from the population in the set of the amounts of electricity calculated for each of the multiple water electrolysis cells CL. In this way, an abnormality may be determined using the calculated amount of electricity instead of a preset threshold.

[0043] In the above embodiment, the electrochemical device to be detected is a water electrolysis cell CL that generates an electromotive force when electrical energy is input. However, the detection target may be a lithium ion battery or a fuel cell that generates an electromotive force even when electrical energy is not input.

[0044] In the above embodiment, specific values ​​are given as examples for the voltage value of the DC voltage DC1 of the DC power supply 40, the voltage value and frequency of the AC voltage AC2 of the AC power supply 50, the integral time of the response current, and the application time of the voltage in the abnormality determination, but these values ​​can be modified. For example, the frequency of the AC voltage AC2 may be less than 1 kHz or may exceed 1 kHz. Note that the frequency of the AC voltage AC2 is preferably 10 Hz or more and 10 kHz or less. If the frequency is within this range, the integral calculation of the response current is easy, and the time for applying the voltage to the detection target to detect an abnormality can be reduced.

[0045] In the above embodiment, the voltage value of the DC voltage DC1 of the DC power supply 40 and the maximum voltage value of the AC voltage AC2 of the AC power supply 50 are set to be the same, but they may be set to different values. For example, when the AC voltage AC2 is 0.06 V, the DC voltage DC1 may be set to 0.10 V, which is higher than the AC voltage AC2.

[0046] In the above embodiment, an example was given as specific values ​​for the resistances R0, R1, R2 and the capacitance C1 in the equivalent circuit shown in FIG. 2, but these values ​​can be modified. For example, a value other than 50 Ω may be set as the resistance R2 when an internal break occurs as an abnormality. Also, 5.0×10 12 A value other than Ω may be set.

[0047] Although the present aspect has been described above based on the embodiment and modified examples, the above-mentioned embodiment of the aspect is intended to facilitate understanding of the present aspect and does not limit the present aspect. The present aspect may be modified or improved without departing from the spirit and scope of the claims, and equivalents are included in the present aspect. Furthermore, if a technical feature is not described as essential in this specification, it may be deleted as appropriate.

[0048] The present invention can also be realized in the following forms. [Application example 1] An abnormality detection device for detecting an abnormality in a detection target including an electrochemical device, A voltage application unit that applies a voltage to the detection object; a current acquisition unit that acquires a response current of the detection target to which a voltage is applied; A calculation unit that calculates an amount of electricity by integrating the acquired response current for a predetermined time period; Equipped with The voltage application unit applies a voltage obtained by adding a DC voltage and an AC voltage to the detection object. [Application example 2] The abnormality detection device according to Application Example 1, further comprising: A temperature acquisition unit that acquires a temperature of the detection object; a determination unit that determines whether or not an abnormality has occurred in the detection object by comparing the amount of electricity calculated by the calculation unit with a threshold value that is set in advance according to a temperature of the detection object; and An abnormality detection device comprising: [Application example 3] The abnormality detection device according to the first or second aspect of the present invention, The voltage application unit sets a voltage value of the DC voltage and a maximum voltage value of the AC voltage to be the same. [Application example 4] The abnormality detection device according to any one of Application Examples 1 to 3, The voltage application unit sets the frequency of the AC voltage to 10 Hz or more and 10 kHz or less. [Application example 5] An anomaly detection method for detecting an anomaly in a detection target including an electrochemical device, the method comprising: a voltage application step of applying a voltage obtained by adding a DC voltage and an AC voltage to the detection target; a current acquiring step of acquiring a response current of the detection target to which a voltage is applied; A calculation step of integrating the acquired response current for a predetermined time period to calculate an amount of electricity; The anomaly detection method comprises: [Application Example 6] A computer program comprising: A voltage application function that applies a voltage to a detection target including an electrochemical device; a current acquisition function for acquiring a response current of the detection target to which a voltage is applied; A calculation function for integrating the acquired response current for a predetermined time period to calculate an electrical quantity; Run the following on your computer: The voltage application function is a computer program that applies a voltage obtained by adding a DC voltage and an AC voltage to the detection target. [Explanation of symbols]

[0049] 10...Control device 20…CPU 21...Voltage control unit (voltage application unit) 22...Temperature acquisition section 23…Current acquisition section 24...Calculation section 25...Judgment section 30...Storage section 31...Threshold database 32...Electric quantity database 40...DC power supply (voltage application section) 50...AC power supply (voltage application section) 61...Thermometer 62...Ammeter 63…Voltmeter 100...Anomaly detection device AC1…Voltage AC2…AC voltage C1…Capacitance CL: Water electrolysis cell (detection target) DC1: DC voltage PW…Power supply R0~R2…Resistance

Claims

1. An abnormality detection device for detecting an abnormality in a detection target including an electrochemical device, A voltage application unit that applies a voltage to the detection object; a current acquisition unit that acquires a response current of the detection target to which a voltage is applied; A calculation unit that calculates an amount of electricity by integrating the acquired response current for a predetermined time period; Equipped with The voltage application unit applies a voltage obtained by adding a DC voltage and an AC voltage to the detection object.

2. The abnormality detection device according to claim 1, further comprising: A temperature acquisition unit that acquires a temperature of the detection object; a determination unit that determines whether or not an abnormality has occurred in the detection object by comparing the amount of electricity calculated by the calculation unit with a threshold value that is set in advance according to a temperature of the detection object; An abnormality detection device comprising:

3. The abnormality detection device according to claim 1 , The voltage application unit sets a voltage value of the DC voltage and a maximum voltage value of the AC voltage to be the same.

4. The abnormality detection device according to any one of claims 1 to 3, The voltage application unit sets the frequency of the AC voltage to 10 Hz or more and 10 kHz or less.

5. An anomaly detection method for detecting an anomaly in a detection target including an electrochemical device, the method comprising: a voltage application step of applying a voltage obtained by adding a DC voltage and an AC voltage to the detection target; a current acquiring step of acquiring a response current of the detection target to which a voltage is applied; A calculation step of integrating the acquired response current for a predetermined time period to calculate an amount of electricity; The anomaly detection method comprises:

6. A computer program comprising: A voltage application function that applies a voltage to a detection target including an electrochemical device; a current acquisition function for acquiring a response current of the detection target to which a voltage is applied; A calculation function for integrating the acquired response current for a predetermined time period to calculate an electrical quantity; Run the following on your computer: The voltage application function is a computer program that applies a voltage obtained by adding a DC voltage and an AC voltage to the detection target.

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