Method for diagnosing electrolysis unit, method for diagnosing electrolysis device, device for diagnosing electrolysis unit, operation system, and storage medium

Abstract

The embodiment of the invention relates to a diagnosis method for an electrolysis unit, a diagnosis method for an electrolysis device, a diagnosis device for an electrolysis unit, an operation system, and a storage medium. The technical problem to be solved by the present invention is to provide a method for diagnosing an electrolysis cell, a method for diagnosing an electrolysis device, a device for diagnosing an electrolysis cell, an operation system, and a storage medium, with which it is possible to appropriately grasp the degradation state and operation state of the electrolysis cell. In an embodiment, a diagnostic method for an electrolysis unit is provided in which an electrochemical reaction using a supplied supply occurs by an input of power. In the diagnostic method, the membrane resistance caused by the membrane, the anode resistance caused by the anode, and the cathode resistance caused by the cathode are estimated, respectively, from the measurement results of the frequency characteristics of the impedance for the electrolysis cell. In the diagnostic method, the operating state and the deterioration state of the electrolysis cell are determined on the basis of the respective temporal changes in the membrane resistance, the anode resistance, and the cathode resistance.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to a diagnosis method of an electrolytic unit, a diagnosis method of an electrolytic device, a diagnosis device of an electrolytic unit, an operation system, and a storage medium. BACKGROUND

[0002] An electrolytic unit in which an electrochemical reaction using a supply is caused by input of electric power is used in a state in which the supply is supplied. For example, in an electrolytic unit (water electrolytic unit) in which water is supplied as a supply, electrolysis of water is caused as an electrochemical reaction by input of electric power. Then, as a product generated by the electrochemical reaction in the electrolytic unit, hydrogen or the like is generated, and the generated hydrogen or the like is recovered.

[0003] In the electrolytic unit as described above, when continuous operation is performed, material degradation or the like occurs, and the degradation is intensified. In addition, in a state in which the electrolytic unit is operated, an operation abnormality such as excessive temperature rise, excessive current, and supply shortage of the supply can occur in the electrolytic unit. Therefore, in the state in which the electrolytic unit is operated, it is required to appropriately grasp, for example, occurrence of material degradation and an operation abnormality or the like, and thus to appropriately grasp a degradation state and an operation condition of the electrolytic unit. SUMMARY

[0004] The present application relates to a diagnosis method of an electrolytic unit, a diagnosis method of an electrolytic device, a diagnosis device of an electrolytic unit, an operation system, and a storage medium, which can appropriately grasp a degradation state and an operation condition of the electrolytic unit.

[0005] According to the embodiments, a diagnosis method of an electrolytic unit in which an electrochemical reaction using a supplied supply is caused by input of electric power is provided. In the diagnosis method, for the electrolytic unit, a membrane resistance caused by a membrane, an anode resistance caused by an anode, and a cathode resistance caused by a cathode are respectively estimated from a measurement result of a frequency characteristic of an impedance. In the diagnosis method, an operation condition and a degradation state of the electrolytic unit are determined from a temporal change of each of the membrane resistance, the anode resistance, and the cathode resistance.

[0006] According to the above structure, a diagnosis method of an electrolytic unit, a diagnosis method of an electrolytic device, a diagnosis device of an electrolytic unit, an operation system, and a storage medium, which can appropriately grasp a degradation state and an operation condition of the electrolytic unit, can be provided. BRIEF DESCRIPTION OF DRAWINGS

[0007] Figure 1 A schematic view showing an example of the operation system of the first embodiment.

[0008] Figure 2A flowchart schematically showing an example of the estimation processing of the resistance components of the electrolytic unit by the processing circuit or the like in the first embodiment.

[0009] Figure 3 A schematic diagram showing an example of the equivalent circuit of the equivalent circuit model for estimating the plurality of resistance components of the electrolytic unit in the first embodiment.

[0010] Figure 4 A schematic diagram for explaining an example of the processing of estimating the plurality of resistance components of the electrolytic unit by the processing circuit or the like in the first embodiment.

[0011] Figure 5 A flowchart schematically showing an example of the determination processing of the operating condition and the deterioration state of the electrolytic unit by the processing circuit or the like in the first embodiment.

[0012] Figure 6 A schematic diagram showing a verification result of the verification associated with the first embodiment or the like.

[0013] Figure 7 A flowchart schematically showing an example of the determination processing of the operating condition and the deterioration state of the electrolytic unit by the processing circuit or the like in the first modification.

[0014] Figure 8 A flowchart schematically showing an example of the processing related to the input of the diagnosis current to the electrolytic unit by the processing circuit or the like in the third modification.

[0015] Figure 9 A schematic diagram for explaining an example of the timing of the input of the diagnosis current to the electrolytic unit in the third modification.

[0016] Figure 10 A schematic diagram showing the structure of the electrolytic device of the fourth modification.

[0017] REFERENCE NUMERALS

[0018] 1: operating system; 2: electrolytic unit; 3: electrolytic cell; 6: power regulator; 7: current measurement circuit; 8: voltage measurement circuit; 10: electrolytic device; 12: supply pump; 13: flow sensor; 15: temperature adjustment unit; 17: temperature sensor; 20: diagnosis device; 21: processing circuit; 22: storage medium; 25: diagnosis program; 28: power supply circuit; Rm: membrane resistance; Ra: anode resistance; Rc: cathode resistance; γm, γa, γc: time change rate; εm, εa, εc: time change amount. DETAILED DESCRIPTION

[0019] Embodiments will be described below with reference to the drawings.

[0020] (First Embodiment)

[0021] First, as an example of an implementation method, the first implementation method will be described. Figure 1 A schematic diagram illustrating an example of the operating system 1 of the first embodiment. Figure 1 As shown, the operating system 1 includes an electrolysis unit 2, which is operated within the operating system 1. Figure 1 In one example, the electrolysis unit 2 includes an electrolysis block or electrolysis module formed by electrically connecting multiple electrolysis cells 3. Furthermore, the electrolysis unit 2 is formed by at least one of a series connection structure where multiple electrolysis cells 3 are electrically connected in series and a parallel connection structure where multiple electrolysis cells 3 are electrically connected in parallel. Additionally, in one example, the electrolysis unit 2 may be formed from a single electrolysis cell 3.

[0022] The electrolytic cell 3 constituting the electrolysis unit 2 includes an anode and a cathode. In the electrolytic cell 3, a membrane such as an ion exchange membrane or an electrolyte membrane is located between the anode and the cathode. Furthermore, in the electrolytic cell 3, at least one of the anode and the cathode contains a catalyst, or both the anode and the cathode may contain catalysts. In the electrolytic cell 3, the catalyst used as the cathode may be, for example, a metal or alloy containing any element from Pt, Ru, Rh, Pd, Au, Os, Ir, etc., and the catalyst used as the anode may be, for example, a metal, alloy, or oxide containing any element from Ir, Ru, Rh, Pd, Au, Os, etc.

[0023] Electrolysis unit 2 can be connected to power system 5, and when electrolysis unit 2 is running, power is input from power system 5 to electrolysis unit 2. Examples of power system 5 include power systems that supply power from generators that generate electricity using natural energy sources such as sunlight and wind power, and power systems that supply power from power plants.

[0024] The operating system 1 includes a power regulator 6 as a power regulation unit. The power regulator 6 performs power conversion on the power from the power system 5, inputting the converted power as operating power to the electrolysis unit 2. At this time, the power regulator 6, for example, converts the AC power from the power system 5 into DC power within the voltage range corresponding to the electrolysis unit 2 through AC / DC conversion and transformation, and inputs the converted DC power to the electrolysis unit 2. Furthermore, in the operating system 1, the magnitude of the power input to the electrolysis unit 2 as operating power varies correspondingly with the operating state of the power regulator 6. Therefore, the magnitude of the operating current input to the electrolysis unit 2 and the magnitude of the voltage applied to the electrolysis unit 2 vary correspondingly with the operating state of the power regulator 6, thereby regulating the current and voltage of the electrolysis unit 2.

[0025] In addition, supplies are provided to electrolysis unit 2, in Figure 1In the example, water is supplied as the feed to electrolysis unit 2. Thus, electrolysis unit 2 becomes a water electrolysis unit, and each of the electrolysis cells 3 constituting electrolysis unit 2 becomes a water electrolysis cell. During operation of electrolysis unit 2, electricity is input to electrolysis unit 2 while the feed is being supplied. While the feed is being supplied, by inputting electricity to electrolysis unit 2, an electrochemical reaction utilizing the feed occurs within electrolysis unit 2. Figure 1 In the example, by inputting electricity into the electrolysis unit 2, the electrolysis of water occurs as an electrochemical reaction in each of the electrolysis cells 3 that constitute the electrolysis unit 2.

[0026] When electrochemical reactions such as water electrolysis occur in electrolysis unit 2 due to the input of electricity, the anode has a relatively higher potential than the cathode in each electrolysis cell 3 constituting electrolysis unit 2. At this time, the potentials of the anode and cathode in each electrolysis cell 3 vary correspondingly to the materials constituting the electrodes and the operating conditions of electrolysis unit 2. In each electrolysis cell 3, under the condition of water electrolysis, i.e., under the condition of operating electrolysis unit 2, at least hydrogen ions and oxygen are generated at the anode. Then, in each electrolysis cell 3, the hydrogen ions generated at the anode move through the membrane to the cathode side, generating hydrogen at the cathode. In electrolysis unit 2, the products generated by the electrochemical reaction are recovered. Figure 1 In the example, hydrogen, a product of the electrolysis of water, is recovered.

[0027] The operating system 1 includes a current measuring circuit 7 and a voltage measuring circuit 8. The current measuring circuit 7 includes, for example, a current sensor, and the voltage measuring circuit 8 includes, for example, a voltage sensor. When operating power is supplied to the electrolysis unit 2, the current measuring circuit 7 measures the current in the electrolysis unit 2, i.e., the current input to the electrolysis unit 2. Conversely, when operating power is supplied to the electrolysis unit 2, the voltage measuring circuit 8 measures the voltage in the electrolysis unit 2, i.e., the voltage applied to the electrolysis unit 2.

[0028] Furthermore, the operating system 1 includes a water tank 11, a supply pump 12, and a flow sensor 13. Water, the feed material for the electrolysis unit 2, is stored in the water tank 11. The water in the water tank 11 is supplied to the electrolysis unit 2 by the operation of the supply pump 12. The water supply status to the electrolysis unit 2, including the amount of water supplied, changes correspondingly to the operating status of the supply pump 12. The flow sensor 13 detects, for example, the flow rate of water from the supply pump 12 to the electrolysis unit 2, to detect the amount of water supplied to the electrolysis unit 2 as the feed material.

[0029] In addition, the operating system 1 includes a temperature control unit 15, a flow path 16, and a temperature sensor 17. The temperature control unit 15 includes a heat exchanger 18. Cooling fluids such as cooling water or cooling gas flow in the flow path 16. The temperature control unit 15 uses the heat exchanger 18 to move heat between the cooling fluid flowing through the flow path 16 and the electrolysis unit 2, thereby regulating the temperature of the electrolysis unit 2. The temperature of the electrolysis unit 2 changes in accordance with the operating state of the temperature control unit 15, including the heat exchanger 18. The temperature sensor 17 detects the temperature of the electrolysis unit 2.

[0030] In this embodiment, the operating system 1 includes a diagnostic device 20 as a processing unit. The diagnostic device 20 performs processing related to the diagnosis of the electrolysis unit 2 in operation. Therefore, in the operating system 1, the electrolysis unit 2 becomes the object of diagnosis by the diagnostic device 20. Figure 1 In the example, the diagnostic device 20 is composed of a computer such as a server, and has a processing circuit 21 and a storage medium 22.

[0031] The processing circuit 21 is composed of a processor or integrated circuit, etc. The processor or other components constituting the processing circuit 21 include any of the following: CPU (Central Processing Unit), ASIC (Application Specific Integrated Circuit), microcomputer, FPGA (Field Programmable Gate Array), and DSP (Digital Signal Processor). The processing circuit 21 can be composed of one processor or multiple processors. Furthermore, the storage medium 22 can be a main storage device such as a memory or an auxiliary storage device. In the diagnostic device 20, only one storage medium 22 may be provided, or multiple storage media 22 may be provided.

[0032] In the diagnostic device 20, the processing circuit 21 performs processing by executing programs stored in the storage medium 22. Furthermore, the storage medium 22 stores data used for the processing in the processing circuit 21. In one example, the program executed by the processing circuit 21 in the diagnostic device 20 may be stored on a computer (server) connected via a network such as the Internet, or a server in a cloud environment. In this case, the processing circuit 21 downloads the program via the network.

[0033] exist Figure 1In the example, storage medium 22 stores a data management program 23 and a diagnostic program 25 as programs executed in processing circuit 21. Processing circuit 21 executes the data management program 23 to write data to and read data from storage medium 22. Additionally, diagnostic program 25 includes a resistance calculation program 26 and a determination program 27. In the diagnosis of electrolysis unit 2, processing circuit 21 performs the processing described later based on diagnostic program 25.

[0034] Furthermore, in one example, the diagnostic device 20 is composed of multiple computers, such as multiple servers, and the processors of the multiple computers cooperate to perform subsequent processing based on the diagnostic program 25. In the case where the diagnostic device 20 is composed of multiple computers, the multiple computers constituting the diagnostic device 20 can communicate with each other wirelessly or via wired means.

[0035] In another example, a cloud server in a cloud environment constitutes at least a part of the diagnostic device 20. The infrastructure of the cloud environment consists of virtual processors such as virtual CPUs and cloud storage. When at least a part of the diagnostic device 20 is constituted by a cloud server, the virtual processor performs at least a portion of the processing described later based on the diagnostic program 25. Furthermore, the program executed by the virtual processor and the data used for processing within the virtual processor are stored in the cloud storage.

[0036] In one example, a user interface may be provided for the diagnostic device 20. In this case, the user of the operating system 1 or others inputs various operations, including operations related to the operation and diagnosis of the electrolysis unit 2, through the user interface. Therefore, any one of buttons, a mouse, a touch panel, or a keyboard may be provided as the operation unit for the user to input operations. Furthermore, a notification unit may be provided on the user interface to inform the user of information related to the electrolysis unit 2. This notification unit may provide information through screen display or sound transmission. Moreover, the user interface may be provided separately from the computer or other components constituting the diagnostic device 20. However, providing a user interface is not mandatory.

[0037] exist Figure 1 In the example, the processing circuit 21 of the diagnostic device 20 acquires the measurement results of the current of the electrolysis unit 2 by the current measurement circuit 7 and the measurement results of the voltage of the electrolysis unit 2 by the voltage measurement circuit 8. Then, based on the measurement results of the current and voltage of the electrolysis unit 2, the processing circuit 21 controls the operation of the power regulator 6 and adjusts the amount of operating power input to the electrolysis unit 2. Accordingly, it adjusts the operating current input to the electrolysis unit 2 and the voltage applied to the electrolysis unit 2.

[0038] In addition, Figure 1In the example, the processing circuit 21 acquires the detection result of the water supply volume by the flow sensor 13. Then, based on the detection result of the water supply volume to the electrolysis unit 2, the processing circuit 21 controls the operation of the supply pump 12 to adjust the flow rate of the water supplied to the electrolysis unit 2. Additionally, the processing circuit 21 acquires the detection result of the temperature of the electrolysis unit 2 by the temperature sensor 17. Then, based on the detection result of the temperature of the electrolysis unit 2, the processing circuit 21 controls the operation of the temperature regulating unit 15, including the heat exchanger 18, to regulate the temperature of the electrolysis unit 2.

[0039] Furthermore, a diagnostic power supply circuit 28 is provided in the operating system 1. During the diagnostic process of the electrolysis unit 2, the power supply circuit 28, for example, converts power from the power system 5 into diagnostic power to generate diagnostic power for diagnosing the electrolysis unit 2. Then, during the diagnostic process of the electrolysis unit 2, the processing circuit 21, etc., controls the operation of the power supply circuit 28 to input the diagnostic power into the electrolysis unit 2. By inputting the diagnostic power into the electrolysis unit 2, a diagnostic current is input into the electrolysis unit 2. With operating power input into the electrolysis unit 2, the diagnostic current is superimposed on the operating current input into the electrolysis unit 2 by inputting the diagnostic power from the power supply circuit 28 into the electrolysis unit 2.

[0040] In this embodiment, the diagnostic program 25 is executed by the processing circuit 21 and the like to repeatedly perform diagnostic processing on the operating electrolytic unit 2 over time. In one example, the diagnostic processing is performed periodically on the electrolytic unit 2, which is the object of the diagnostic. In one diagnostic processing of the electrolytic unit 2, the resistance component of the electrolytic unit 2 is calculated by executing the resistance calculation program 26 included in the diagnostic program 25.

[0041] Furthermore, in the first diagnostic process of electrolysis unit 2, after the resistance component calculation process is performed, the judgment procedure 27 included in the diagnostic procedure 25 is executed, thereby performing a judgment process on electrolysis unit 2 based on the resistance component calculation results. In the judgment process of electrolysis unit 2, the operating condition and deterioration state of electrolysis unit 2 are judged. By repeatedly performing the diagnostic process described above over time, the resistance component calculation process and the judgment process on the operating condition and deterioration state are repeatedly performed on the operating electrolysis unit 2 over time.

[0042] Figure 2 The flowchart illustrates, for the sake of simplicity, an example of the calculation process for the resistance component of the electrolysis unit 2 performed by the processing circuit 21, etc., in the first embodiment. In each diagnostic process for the electrolysis unit 2, which is repeated over time, before performing the subsequent determination process for the operating condition and deterioration state of the electrolysis unit 2, a... Figure 2 The example calculation process. When it begins Figure 2In the example processing, the processing circuit 21, etc., controls the drive of the power supply circuit 28, etc., so that the diagnostic current is input from the power supply circuit 28 to the electrolysis unit 2 (S101). The diagnostic current is a current signal corresponding to the measurement of the impedance of the electrolysis unit 2.

[0043] In one example, an alternating current with a periodically changing current value is input to the electrolysis unit 2 as a diagnostic current. In this case, the alternating current is input to the electrolysis unit 2 with arbitrary waveforms such as sine waves, triangular waves, and sawtooth waves. Furthermore, when generating the alternating current as a diagnostic current, the processing circuit 21, etc., controls the drive of the power supply circuit 28, etc., to adjust the frequency of the alternating current input to the electrolysis unit 2. Then, the processing circuit 21, etc., inputs the alternating current as a diagnostic current to the electrolysis unit 2 while the alternating current changes to multiple frequencies over time. In another example, a pseudo-random pulse signal such as an M-sequence signal is input to the electrolysis unit 2 as a diagnostic current. In this case, the pseudo-random pulse signal input to the electrolysis unit 2 contains multiple pulses with different pulse widths.

[0044] Then, with the diagnostic current input to the electrolysis unit 2, the processing circuit 21, etc., causes the current measuring circuit 7 to measure the current of the electrolysis unit 2 and the voltage measuring circuit 8 to measure the voltage of the electrolysis unit 2. Then, the processing circuit 21, etc., acquires timing data (S102) representing the time changes (time history records) of the current and voltage of the electrolysis unit 2 under the condition that the diagnostic current is input to the electrolysis unit 2. The time change of the current of the electrolysis unit 2 represented by the timing data is generated based on the measurement results of the current measuring circuit 7, and the time change of the voltage of the electrolysis unit 2 represented by the timing data is generated based on the measurement results of the voltage measuring circuit 8.

[0045] In one example, a diagnostic current is input to electrolysis unit 2 while the operating current is being input—that is, while an electrochemical reaction is occurring in electrolysis unit 2 due to the input of operating power. In this case, the diagnostic current corresponding to the impedance measurement is superimposed on the operating current input to electrolysis unit 2 to generate the electrochemical reaction. Thus, timing data representing the time changes of current and voltage in electrolysis unit 2 under the condition of input diagnostic current are measured simultaneously with the operation of electrolysis unit 2.

[0046] When the aforementioned timing data (measurement data) is acquired, the processing circuit 21 and the like measure the frequency characteristics of the impedance of the electrolytic unit 2 by analyzing the acquired timing data (S103). Furthermore, when the timing data is acquired, the input of diagnostic current to the electrolytic unit 2 is stopped. In one example, when measuring the frequency characteristics of the impedance of the electrolytic unit 2, a current spectrum representing the frequency characteristics of the current of the electrolytic unit 2 is generated by performing a Fourier transform on the time variation of the current of the electrolytic unit 2 represented by the aforementioned timing data, i.e., the current timing data contained in the timing data. Moreover, a voltage spectrum representing the frequency characteristics of the voltage of the electrolytic unit 2 is generated by performing a Fourier transform on the time variation of the voltage of the electrolytic unit 2 represented by the aforementioned timing data, i.e., the voltage timing data contained in the timing data.

[0047] Then, using the current spectrum and voltage spectrum data of electrolytic cell 2, calculations are performed to determine the impedance spectrum data, which represents the frequency characteristics of the impedance of electrolytic cell 2. For example, the impedance spectrum data of electrolytic cell 2 is calculated by dividing the voltage spectrum data of electrolytic cell 2 by the current spectrum data of electrolytic cell 2. The impedance spectrum data of electrolytic cell 2 shows the impedance of electrolytic cell 2 at various frequencies across multiple frequencies.

[0048] Furthermore, a method for calculating the frequency characteristics of battery impedance using current-time data about the battery current and voltage-time data about the battery voltage is shown in Reference 1 (Japanese Patent Application Publication No. 2014-126532). In the embodiment, the frequency characteristics of the impedance of the electrolytic unit 2 can be calculated in the same manner as the calculation of the frequency characteristics of battery impedance in Reference 1. In this case, the processing circuit 21 calculates the autocorrelation function of the current spectrum data of the electrolytic unit 2, and calculates the cross-correlation function between the current spectrum data and the voltage spectrum data of the electrolytic unit 2. Then, the processing circuit 21 uses the calculated autocorrelation function and cross-correlation function to calculate the frequency characteristics of the impedance of the electrolytic unit 2.

[0049] In another example, alternating current is input to the electrolytic cell 2 as a diagnostic current at multiple frequencies. The processing circuit 21, etc., calculates the impedance of the electrolytic cell 2 for each of these frequencies based on the current and voltage values ​​of the electrolytic cell 2, expressed as timing data (measurement data), etc. For example, the impedance of the electrolytic cell 2 is calculated by dividing the voltage value of the electrolytic cell 2 by the current value for each of the multiple frequencies. Based on this, the frequency characteristic of the impedance of the electrolytic cell 2, representing the impedance of the electrolytic cell 2 at each of the multiple frequencies, is calculated.

[0050] When the frequency characteristics of the impedance of electrolysis unit 2 are measured, the processing circuit 21 and the like calculate the membrane resistance Rm, anode resistance Ra, and cathode resistance Rc as resistance components based on the measurement results of the frequency characteristics of the impedance of electrolysis unit 2 (S104). The membrane resistance Rm is the resistance component caused by the membrane of the electrolytic cell 3 constituting electrolysis unit 2. Furthermore, the anode resistance Ra is the resistance component caused by the anode of the electrolytic cell 3 constituting electrolysis unit 2, mainly caused by the catalyst at the anode. Moreover, the cathode resistance Rc is the resistance component caused by the cathode of the electrolytic cell 3 constituting electrolysis unit 2, mainly caused by the catalyst at the cathode.

[0051] For example, the measurement results of the frequency characteristics of the impedance of electrolytic unit 2 and the equivalent circuit model of electrolytic unit 2 are used to calculate multiple resistance components of electrolytic unit 2, namely, the film resistance Rm, anode resistance Ra, and cathode resistance Rc of electrolytic unit 2. The equivalent circuit model of electrolytic unit 2 is stored in storage medium 22, etc., and the equivalent circuit of electrolytic unit 2 is shown in the equivalent circuit model. In the equivalent circuit of the equivalent circuit model, circuit parameters (electrical characteristic parameters) including the resistance components to be calculated are set. Therefore, circuit parameters including film resistance Rm, anode resistance Ra, and cathode resistance Rc are set in the equivalent circuit.

[0052] Figure 3 This is a schematic diagram illustrating an example of an equivalent circuit for calculating the multiple resistive components of the electrolysis unit 2 in the first embodiment. Figure 3 In the example equivalent circuit, the film resistance Rm, anode resistance Ra, and cathode resistance Rc are set as circuit parameters. Additionally, in Figure 3 In the equivalent circuit of the example, the capacitive components caused by the anode, namely capacitance Ca and the capacitive components caused by the cathode, namely capacitance Cc, are also set as circuit parameters. Furthermore, the impedance during the diffusion process of hydrogen ion plasma, namely the Warburg impedance Zw, is set as a circuit parameter. In electrolysis unit 2, the resistive component of the Warburg impedance Zw is the diffusion resistance.

[0053] In the equivalent circuit model used to calculate the multiple resistance components of electrolytic unit 2, the relationship between the circuit parameters set in the equivalent circuit and the impedance of electrolytic unit 2 is shown. For example, the formula for calculating the impedance of electrolytic unit 2 using circuit parameters and frequency is shown. When calculating the film resistance Rm, anode resistance Ra, and cathode resistance Rc of electrolytic unit 2, the processing circuit 21, etc., performs fitting calculations, for example, using the relationship between the circuit parameters and impedance shown in the equivalent circuit model and the measurement results of the frequency characteristics of the impedance of electrolytic unit 2.

[0054] In the fitting calculation using the equivalent circuit model, circuit parameters set in the equivalent circuit, including the multiple resistance components to be calculated, are used as variables in the calculation, and the circuit parameters as variables are calculated. Furthermore, in the fitting calculation, at each of the multiple frequencies where impedance is measured, the values ​​of the circuit parameters as variables are calculated while minimizing the difference between the calculated impedance value obtained using the relationship shown by the equivalent circuit model and the measured impedance value as the measurement result. The circuit parameters are calculated using the fitting calculation, thereby calculating the film resistance Rm, anode resistance Ra, and cathode resistance Rc as multiple resistance components for electrolytic unit 2.

[0055] Figure 4 A schematic diagram illustrating an example of the processing of multiple resistance components of the electrolysis unit 2 performed by the processing circuit 21, etc., in the first embodiment. Figure 4 The graph shows the real component of impedance Zre on the horizontal axis and the imaginary component of impedance -Zim on the vertical axis. Therefore, in Figure 4 The measurement results of the frequency characteristics of the impedance of electrolytic unit 2 are shown in the diagram using a complex impedance diagram (Cole-Cole diagram). Additionally, in... Figure 4 In the figure, the measurement results of the frequency characteristics of the impedance of electrolytic unit 2 are shown by solid lines.

[0056] like Figure 4 As shown, in the complex impedance diagram representing the measurement results of the frequency characteristics of the impedance of electrolytic unit 2, a convex arc portion A is formed on the negative side of the imaginary component of the impedance. The arc portion A has a convex vertex T, at which the imaginary component of the impedance is negative. Furthermore, in the complex impedance diagram, on the side with a frequency higher than the vertex T of the convex shape of the arc portion A, there exists an intersection point D that intersects the axis of the real component, i.e., the horizontal axis.

[0057] exist Figure 4 In the example, by performing fitting calculations using an equivalent circuit model as described above, the real component (positive value) of the impedance at the intersection D of the complex impedance diagram is calculated and used as the membrane resistance Rm of electrolytic unit 2. Additionally, in Figure 4 In the example complex impedance diagram, the impedance component on the side with a frequency lower than that of the arc portion A, i.e., the impedance component of region α, is equivalent to the Warburg impedance.

[0058] By performing fitting calculations using an equivalent circuit model as described above, the anode impedance caused by the anode and the cathode impedance caused by the cathode are separated from the complex impedance diagram representing the frequency characteristics of the impedance of electrolytic unit 2. Accordingly, the arc portion A of the complex impedance diagram is separated into an arc portion Aa representing the anode impedance and an arc portion Ac representing the cathode impedance. Figure 4 In the diagram, the arc portion Aa of the anode impedance is represented by a dashed line, and the arc portion Ac of the cathode impedance is represented by a single-dot dashed line.

[0059] In addition, Figure 4 In the example, by performing fitting calculations using an equivalent circuit model as described above, the diameter of the arc portion Aa of the anode impedance is calculated, which serves as the anode resistance Ra of electrolytic unit 2. Similarly, the diameter of the arc portion Ac of the cathode impedance is calculated, which serves as the cathode resistance Rc of electrolytic unit 2. Here, the arc portion Aa of the anode impedance bulges on the negative side of the imaginary component of the impedance, and the imaginary component of the impedance is negative at the apex Ta of the convex shape of the arc portion Aa. Likewise, the arc portion Ac of the cathode impedance bulges on the negative side of the imaginary component of the impedance, and the imaginary component of the impedance is negative at the apex Tc of the convex shape of the arc portion Ac.

[0060] Furthermore, Reference 2 (Japanese Patent Application Publication No. 2017-106889) illustrates a method in which the values ​​of the circuit parameters set in the equivalent circuit model are calculated by fitting the relationship between the frequency characteristics of the battery's impedance and the circuit parameters (circuit constants) shown in the equivalent circuit model of the battery, and the resistance component of the battery is calculated. In the implementation, the membrane resistance Rm, anode resistance Ra, and cathode resistance Rc of the electrolytic unit 2 can be calculated in the same manner as the calculation of the resistance component of the battery in Reference 2.

[0061] Figure 5 The flowchart illustrates, for the sake of simplicity, an example of the process performed by the processing circuit 21 and the like in the first embodiment to determine the operating status and deterioration state of the electrolysis unit 2. In each diagnostic process for the electrolysis unit 2, which is repeated over time, after the aforementioned calculation process for the resistance component of the electrolysis unit 2 is performed, the following steps are taken: Figure 5 The example is determined by processing. Furthermore, the calculation results of the membrane resistance Rm, anode resistance Ra, and cathode resistance Rc of electrolytic unit 2 are based on the calculation processing of the resistance components. Figure 5 The example of judgment processing.

[0062] When it started Figure 5In the example processing, the processing circuit 21 and the like calculate the time change ratios γm, γa, and γc for the membrane resistance Rm, anode resistance Ra, and cathode resistance Rc of the electrolysis unit 2, respectively, as parameters associated with time change (S111). Each time change ratio γm, γa, and γc, as parameters associated with time change, is calculated and used as a determination parameter in the determination process. Here, the time change ratio γm for the membrane resistance Rm is, for example, the ratio of the calculated membrane resistance Rm in the real-time diagnostic process to the calculated membrane resistance Rm in the previous diagnostic process, as the final value. When the membrane resistance Rm remains unchanged since the last diagnostic process, the time change ratio γm is 1. Furthermore, when the membrane resistance Rm increases since the last diagnostic process, the time change ratio γm is a value greater than 1; when the membrane resistance Rm decreases since the last diagnostic process, the time change ratio γm is a value less than 1.

[0063] Furthermore, the time-varying factor γa of the anode resistance Ra is, for example, the ratio of the calculated anode resistance Ra during real-time diagnostic processing to the calculated anode resistance Ra during the previous diagnostic processing, and is used as the final value. If the anode resistance Ra remains unchanged since the last diagnostic processing, the time-varying factor γa is 1. Conversely, if the anode resistance Ra has increased since the last diagnostic processing, the time-varying factor γa is greater than 1; if the anode resistance Ra has decreased since the last diagnostic processing, the time-varying factor γa is less than 1.

[0064] Furthermore, the time-varying ratio γc of the cathode resistance Rc is, for example, the ratio of the calculated cathode resistance Rc during the real-time diagnostic process to the calculated cathode resistance Rc during the previous diagnostic process, and is used as the final value. When the cathode resistance Rc remains constant since the last diagnostic process, the time-varying ratio γc is 1. Conversely, when the cathode resistance Rc has increased since the last diagnostic process, the time-varying ratio γc is greater than 1; when the cathode resistance Rc has decreased since the last diagnostic process, the time-varying ratio γc is less than 1.

[0065] Furthermore, in one example, during the calculation of the time change factors γm, γa, and γc in S111, the processing circuit 21, etc., uses the calculated values ​​of the time change factors of each of the most recent reference number Nref (Nref is a natural number greater than 2) diagnostic processes, including the diagnostic processes currently being performed in real time, as temporary values ​​to calculate the final values ​​of the time change factors. In this case, the processing circuit 21, etc., calculates, for example, the average or median value of the calculated values ​​of the most recent reference number Nref diagnostic processes as the final value for each time change factor γm, γa, and γc, which are used as determination parameters.

[0066] When the final values ​​of each time change factor γm, γa, and γc are calculated in the same manner as in any of the aforementioned examples, the processing circuit 21, etc., uses the time change factors γm, γa, and γc calculated as decision parameters to perform processing after S112. Figure 5 In the example processing, reference ranges are set for the time change factors γm, γa, and γc. Each reference range for the time change factors γm, γa, and γc includes the value of the resistance component corresponding to a resistance value that does not change with time, i.e., 1.

[0067] Therefore, the reference range for the time-varying rate γm includes the value of the film resistance Rm when it does not change with time. That is, the reference range for the time-varying rate γm includes the value 1, which is above the lower limit γmlow and below the upper limit γmup. Similarly, the reference range for the time-varying rate γa includes the value of the anode resistance Ra when it does not change with time. That is, the reference range for the time-varying rate γa includes the value 1, which is above the lower limit γalow and below the upper limit γaup. Furthermore, the reference range for the time-varying rate γc includes the value of the cathode resistance Rc when it does not change with time. That is, the reference range for the time-varying rate γc includes the value 1, which is above the lower limit γclow and below the upper limit γcup.

[0068] In one example, the range of ±Δγm with a median value of 1 is the baseline range for the time change factor γm. Similarly, the range of ±Δγa with a median value of 1 is the baseline range for the time change factor γa, and the range of ±Δγc with a median value of 1 is the baseline range for the time change factor γc. In this case, the values ​​1-Δγm and 1+Δγm are the lower limit γmlow and upper limit γmup of the baseline range for the time change factor γm, respectively. Likewise, the values ​​1-Δγa and 1+Δγa are the lower limit γalow and upper limit γaup of the baseline range for the time change factor γa, respectively, and the values ​​1-Δγc and 1+Δγc are the lower limit γclow and upper limit γcup of the baseline range for the time change factor γc, respectively.

[0069] exist Figure 5In the example processing, when the final values ​​of the time change factors γm, γa, and γc are calculated as determination parameters, the processing circuit 21, etc., compares the calculation results of the processing in S111 with the reference range set as described above for each time change factor γm, γa, and γc. That is, the processing circuit 21, etc., compares the calculation results of the determination parameters, which are parameters related to time change, with the reference range for each resistance of the film resistance Rm, the anode resistance Ra, and the cathode resistance Rc. Then, the processing circuit 21, etc., determines whether at least one of the time change factors γa and γc is lower than the reference range (S112). At this time, the processing circuit 21, etc., determines whether the time change factor γa of the anode resistance Ra is less than the lower limit value γalow of the reference range and whether the time change factor γc of the cathode resistance Rc is less than the lower limit value γclow of the reference range.

[0070] If at least one of the time change factors γa and γc is below the reference range (S112-Yes), that is, if at least one of the time change factors γa and γc is less than the lower limit of the reference range (γalow; γclow), the processing circuit 21 determines whether the time change factor γm is below the reference range (S113). At this time, the processing circuit 21 determines whether the time change factor γm of the film resistance Rm is less than the lower limit of the reference range γmlow.

[0071] If the time change rate γm is lower than the reference range (S113-Yes), that is, if the time change rate γm is less than the lower limit of the reference range γmlow, the processing circuit 21 and the like determine that excessive heating has occurred in the electrolysis unit 2 (S114). On the other hand, if the time change rate γm is not lower than the reference range (S113-No), that is, if the time change rate γm is higher than the lower limit of the reference range γmlow, the processing circuit 21 and the like determine that overcurrent has occurred in the electrolysis unit 2 (S115).

[0072] exist Figure 5In the example, by processing in the order of S112, S113, and S114, the processing circuit 21 determines that excessive heating has occurred in the electrolysis unit 2 based on the condition that the time change factor (γa; γc) of at least one of the anode resistance Ra and the cathode resistance Rc is below a reference range and the time change factor γm of the membrane resistance Rm is below a reference range. Furthermore, by processing in the order of S112, S113, and S115, the processing circuit 21 determines that overcurrent has occurred in the electrolysis unit 2 based on the condition that the time change factor (γa; γc) of at least one of the anode resistance Ra and the cathode resistance Rc is below a reference range and the time change factor γm of the membrane resistance Rm is not below a reference range. Therefore, by determining in S112, it is determined whether at least one of excessive heating and overcurrent has occurred in the electrolysis unit 2. Then, by determining in S113, it is determined which of the two—excessive heating and overcurrent—has occurred in the electrolysis unit 2.

[0073] exist Figure 5 In the example processing, thresholds γmth, γath, and γcth are set for the time change factors γm, γa, and γc used as judgment parameters, respectively. For each time change factor γm, γa, and γc, the thresholds (γmth, γath, and γcth) are set higher than the reference range. Therefore, for the time change factor γm of the film resistance Rm, the threshold γmth is set higher than the upper limit of the reference range γmup. Similarly, for the time change factor γa of the anode resistance Ra, the threshold γath is set higher than the upper limit of the reference range γaup, and for the time change factor γc of the cathode resistance Rc, the threshold γcth is set higher than the upper limit of the reference range γcup.

[0074] In S112, if neither the time change factors γa nor γc are lower than the reference range (S112-No), the processing circuit 21 determines whether one or more of the time change factors γm, γa, and γc exceeds the threshold (γmth; γath; γcth) (S116). At this time, the processing circuit 21 compares the calculation result of the processing in S111 with the threshold (γmth; γath; γcth) for the time change factors (γm; γa; γc) of the film resistance Rm, the anode resistance Ra, and the cathode resistance Rc, and determines whether they are greater than the threshold (γmth; γath; γcth). That is, the processing circuit 21 determines whether the time change factor γm exceeds the threshold γmth, whether the time change factor γa exceeds the threshold γath, and whether the time change factor γc exceeds the threshold γcth.

[0075] If one or more of the time change factors γm, γa, and γc exceed the threshold (γmth; γath; γcth) (S116-Yes), the processing circuit 21 determines that a shortage of the feedstock, i.e., water, has occurred in the electrolysis unit 2 (S117). Figure 5 In the example, by processing in the order of S112, S116, and S117, if the processing circuit 21 determines that a water (supply material) shortage has occurred in the electrolysis unit 2 if the time change factor (γm; γa; γc) of at least one of the membrane resistance Rm, anode resistance Ra, and cathode resistance Rc exceeds a threshold, then the water (supply material) supply in the electrolysis unit 2 is insufficient. Therefore, if the time change factors γa and γc are not lower than the reference range in S112 (S112-No), that is, if no excessive heating or overcurrent occurs in the electrolysis unit 2, the determination in S116 determines whether a water shortage has occurred in the electrolysis unit 2.

[0076] If the time change factors γm, γa, and γc are all below the threshold values ​​(γmth, γath, γcth) (S116-No), the processing circuit 21 determines whether one or more of the time change factors γm, γa, and γc exceed the reference range (S118). At this time, the processing circuit 21 determines whether the time change factors (γm, γa, γc) of the film resistance Rm, anode resistance Ra, and cathode resistance Rc are greater than the upper limit values ​​(γmup, γaup, γcup) of the reference range. That is, the processing circuit 21 determines whether the time change factor γm exceeds the upper limit value γmup of the reference range, whether the time change factor γa exceeds the upper limit value γaup of the reference range, and whether the time change factor γc exceeds the upper limit value γcup of the reference range.

[0077] If one or more of the time change rates γm, γa, and γc exceed the reference range (S118-Yes), that is, if one or more of the time change rates γm, γa, and γc are greater than the upper limit of the reference range (γmup; γaup; γcup), the processing circuit 21 determines that material degradation has occurred in the electrolysis unit 2 (S119). On the other hand, if none of the time change rates γm, γa, and γc exceed the reference range (S118-No), that is, if the time change rates γm, γa, and γc are all below the upper limit of the reference range (γmup; γaup; γcup), the processing circuit 21 determines that neither operational abnormality nor material degradation has occurred in the electrolysis unit 2 (S120).

[0078] exist Figure 5In the example, by processing in the order of S112, S116, S118, and S119, the processing circuit 21 determines that material degradation has occurred in the electrolysis unit 2 if the time change factor (γm; γa; γc) of at least one of the film resistance Rm, anode resistance Ra, and cathode resistance Rc exceeds the reference range, and the time change factors (γm; γa; γc) of all three resistances (Rm, Ra, and Rc) are below the threshold. Therefore, if the time change factors γa and γc are not lower than the reference range in S112, that is, if no excessive heating or overcurrent occurs in the electrolysis unit 2, the determination in S116 and S118 determines whether material degradation has occurred in the electrolysis unit 2.

[0079] By conducting Figure 5 In the example processing, the processing circuit 21, etc., compares the calculation results of real-time diagnostic processing with a reference range that includes values ​​where the resistance does not change over time, based on the time-varying rates (γm; γa; γc) of the membrane resistance Rm, anode resistance Ra, and cathode resistance Rc of the electrolysis unit 2, thereby determining the operating condition and deterioration state of the electrolysis unit 2. Therefore, by performing... Figure 5 In the example processing, the processing circuit 21 and others determine the operating status and deterioration state of the electrolysis unit 2 based on the time changes of the membrane resistance Rm, anode resistance Ra and cathode resistance Rc.

[0080] Here, in electrolysis unit 2, as the temperature rises, according to Arrhenius's law, the resistive components, including the membrane resistance Rm, anode resistance Ra, and cathode resistance Rc, decrease. Therefore, when excessive heating occurs in electrolysis unit 2, the time-varying factors (γm; γa; γc) of the membrane resistance Rm, anode resistance Ra, and cathode resistance Rc, relative to the state without excessive heating, tend to be below the reference range.

[0081] As the current increases, the catalytic activity of the catalysts at the anode and cathode in each electrolytic cell 3 increases according to the Butler-Folmer equation, thus decreasing the anode resistance Ra and the cathode resistance Rc. On the other hand, the membrane resistance Rm is a resistive component that does not follow the Butler-Folmer equation; therefore, even with an increase in current, the membrane resistance Rm remains unchanged or almost unchanged. Thus, when an overcurrent is generated in electrolysis unit 2, the time-varying factors (γa; γc) of the anode resistance Ra and cathode resistance Rc, relative to the state without an overcurrent, tend to be below the reference range. Furthermore, even when an overcurrent is generated in electrolysis unit 2, the time-varying factor γm of the membrane resistance Rm, relative to the state without an overcurrent, is 1 or approximately 1, tending to converge to the reference range.

[0082] In this embodiment, it is determined whether the time-varying rates (γa; γc) of the anode resistance Ra and the cathode resistance Rc are below a reference range. Then, if the time-varying rate (γa; γc) of at least one of the anode resistance Ra and the cathode resistance Rc is below the reference range, it is determined whether the time-varying rate (γm) of the membrane resistance Rm is below the reference range. Then, if the time-varying rate (γm) of the membrane resistance Rm is below the reference range, it is determined that excessive heating has occurred in the electrolysis unit 2; if the time-varying rate (γm) of the membrane resistance Rm is not below the reference range, it is determined that overcurrent has occurred in the electrolysis unit 2. By performing such determinations, the occurrence of excessive heating and overcurrent in the electrolysis unit 2 can be appropriately determined and monitored.

[0083] Furthermore, in electrolysis unit 2, since the reaction rate of water electrolysis decreases when the supply of water as the feed material decreases, the resistive components, including membrane resistance Rm, anode resistance Ra, and cathode resistance Rc, tend to increase sharply in a short period of time. Therefore, when insufficient water supply occurs in electrolysis unit 2, the time-varying factors (γm; γa; γc) of the membrane resistance Rm, anode resistance Ra, and cathode resistance Rc, relative to the state without insufficient water supply, tend to exceed the threshold values ​​(γmth; γath; γcth).

[0084] Furthermore, in electrolysis unit 2, even if material degradation occurs, at least one of the resistance components, including membrane resistance Rm, anode resistance Ra, and cathode resistance Rc, tends to increase. However, in the case of material degradation, the increase in resistance over time is slower compared to the case of insufficient water supply. That is, in the case of material degradation, the rate of increase in resistance over time tends to be lower compared to the case of insufficient water supply. Therefore, even if material degradation occurs in electrolysis unit 2, and at least one of the membrane resistance Rm, anode resistance Ra, and cathode resistance Rc increases over time, the rate of change of the increased resistance component over time (at least one of γm, γa, and γc) although exceeding the reference range, tends to be below the threshold.

[0085] In this embodiment, if the time-varying rates (γa; γc) of both the anode resistance Ra and the cathode resistance Rc are not lower than a reference range, it is determined whether the time-varying rates (γm; γa; γc) of the membrane resistance Rm, anode resistance Ra, and cathode resistance Rc exceed a threshold (γmth; γath; γcth) set above the reference range. Then, if the time-varying rate (γm; γa; γc) of one or more of the membrane resistance Rm, anode resistance Ra, and cathode resistance Rc exceeds the threshold (γmth; γath; γcth), it is determined that a water (supply material) shortage has occurred in the electrolysis unit 2. By making such a determination, the occurrence of a water (supply material) shortage in the electrolysis unit 2 can be appropriately determined and monitored.

[0086] Furthermore, in this embodiment, when the time-varying rates (γa; γc) of both the anode resistance Ra and the cathode resistance Rc are not lower than the reference range, it is determined whether the time-varying rates (γm; γa; γc) of the membrane resistance Rm, anode resistance Ra, and cathode resistance Rc exceed the threshold (γmth; γath; γcth) and whether they exceed the reference range. Then, if the time-varying rate (γm; γa; γc) of one or more of the membrane resistance Rm, anode resistance Ra, and cathode resistance Rc exceeds the reference range, and the time-varying rates (γm; γa; γc) of all three resistances are below the threshold (γmth; γath; γcth), it is determined that material degradation has occurred in the electrolysis unit 2. By performing this determination, the occurrence of material degradation in the electrolysis unit 2 can be appropriately determined and monitored.

[0087] As mentioned above, in this embodiment, by performing Figure 5 The example-based judgment process determines the operating condition and deterioration state of electrolysis unit 2 based on the time-varying changes of membrane resistance Rm, anode resistance Ra, and cathode resistance Rc. Furthermore, by using the judgment process based on the time-varying changes of resistance components, the occurrence of operational anomalies in electrolysis unit 2, such as overheating, overcurrent, and insufficient feedstock supply, can be accurately detected. Additionally, by using the judgment process based on the time-varying changes of resistance components, the occurrence of material deterioration in electrolysis unit 2 can be accurately detected. Therefore, in this embodiment, by using the judgment process based on the time-varying changes of resistance components, the deterioration state and operating condition of electrolysis unit 2 can be accurately determined.

[0088] Furthermore, by monitoring the occurrence of operational anomalies in electrolysis unit 2, users of operating system 1 can identify potential fault components within operating system 1. For example, if overheating is detected in electrolysis unit 2, it can be determined that temperature sensor 17 may have malfunctioned. Similarly, if overcurrent is detected in electrolysis unit 2, it can be determined that current measurement circuit 7 (current sensor) may have malfunctioned. Finally, if insufficient feedstock is detected in electrolysis unit 2, it can be determined that feed pump 12 may have malfunctioned.

[0089] (Verification associated with the first embodiment)

[0090] Here, the following verification was performed as a verification associated with the first embodiment. In the verification, the six electrolysis units β1 to β6, which are water electrolysis units, were evaluated. As electrolysis units β1 to β6, water electrolysis units with at least one different operating condition and deterioration state were used.

[0091] In the verification, the membrane resistance Rm, anode resistance Ra, and cathode resistance Rc were calculated at multiple time points for each electrolysis unit β1 to β6. Then, for each electrolysis unit β1 to β6, the time variation factors γm, γa, and γc were calculated as parameters related to the time variation of the membrane resistance Rm, anode resistance Ra, and cathode resistance Rc. The calculation of the membrane resistance Rm, anode resistance Ra, and cathode resistance Rc, as well as the calculation of the time variation factors γm, γa, and γc, were performed using the method described in the first embodiment. Then, for each electrolysis unit β1 to β6, the calculation results of the time variation factors γm, γa, and γc were compared with… Figure 5 The example uses the same method to determine the operating condition and deterioration status.

[0092] Figure 6 A schematic diagram illustrating the verification results associated with the first embodiment, etc. In Figure 6 In this paper, for each of the six electrolysis units β1 to β6, the calculated results of the time-varying rates (γm; γa; γc) of the membrane resistance Rm, anode resistance Ra, and cathode resistance Rc, as well as the judgment results of the operating condition and deterioration state, are presented in a table. For example... Figure 6As shown, the time-varying ratios γm of the membrane resistance Rm for electrolytic units β1 to β6 are 1.001, 0.940, 0.992, 9.7, 2.01, and 1.87, respectively. Furthermore, the time-varying ratios γa of the anode resistance Ra for electrolytic units β1 to β6 are 1.002, 0.890, 0.780, 8.7, 1.007, and 1.81, respectively, and the time-varying ratios γc of the cathode resistance Rc for electrolytic units β1 to β6 are 0.999, 0.910, 0.810, 8.8, 1.004, and 1.003, respectively.

[0093] Furthermore, in determining the operating conditions and deterioration status of electrolysis units β1 to β6, a range of 0.99 to 1.11 was set as the baseline range for each time-varying factor γm, γa, and γc, and 3.0 was set as the threshold (γmth; γath; γcth). Electrolysis units β1 to β6 were respectively subjected to comparisons with... Figure 5 The same determination process applies to the example. For electrolytic cell β1, the determination is performed in the order of S112-No, S116-No, and S118-No. In S120, it is determined that neither operational abnormality nor material degradation has occurred in electrolytic cell β1. Furthermore, for electrolytic cell β2, the determination is performed in the order of S112-Yes and S113-Yes. In S114, it is determined that excessive heating has occurred in electrolytic cell β2. In electrolytic cell β2, corresponding to the occurrence of excessive heating, the parameters associated with the time change of the resistance component, namely the time change factors γm, γa, and γc, exhibit the tendency described in the first embodiment.

[0094] For electrolysis unit β3, the determination is performed in the order of S112 - Yes and S113 - No. In S115, it is determined that an overcurrent has occurred in electrolysis unit β3. In electrolysis unit β3, corresponding to the occurrence of an overcurrent, the parameters associated with the time change of the resistance component, namely the time change factors γm, γa, and γc, exhibit the tendency described in the first embodiment. Furthermore, for electrolysis unit β4, the determination is performed in the order of S112 - No and S116 - Yes. In S117, it is determined that insufficient water supply has occurred in electrolysis unit β4. In electrolysis unit β4, corresponding to the occurrence of insufficient water supply, the parameters associated with the time change of the resistance component, namely the time change factors γm, γa, and γc, exhibit the tendency described in the first embodiment.

[0095] For each electrolysis unit β5 and β6, a determination is made in the order of S112-No, S116-No, and S118-Yes. In S119, it is determined that material degradation has occurred in each electrolysis unit β5 and β6. In each electrolysis unit β5 and β6, corresponding to material degradation, the parameters associated with the time change of the resistance component, namely the time change factors γm, γa, and γc, exhibit the tendency described in the first embodiment. Furthermore, in electrolysis unit β5, only the time change factor γm of the membrane resistance Rm exceeds the reference range and is below the threshold γmth. Therefore, for electrolysis unit β5, it is determined that material degradation has occurred in the membrane. In addition, in electrolysis unit β6, the time change factors γm of the membrane resistance Rm and the time change factors γa of the anode resistance Ra exceed the reference range and are below the thresholds (γmth; γath). Therefore, for electrolysis unit β6, it is determined that material degradation has occurred in the membrane and anode, respectively.

[0096] (Modified Example)

[0097] The following describes variations of the above-described embodiments, etc. Figure 7 A flowchart illustrating an example of the processing procedure performed by the processing circuit 21, etc., to determine the operating status and deterioration state of the electrolysis unit 2 in the first modification is shown for schematic purposes. Figure 7 In the example determination process, it is also done in accordance with the above-described implementation methods, etc. Figure 5 The same processing method is used for S111 to S115 in the example. However, in this modified example, if the time change ratios γa and γc are not lower than the reference range in S112 (S112-No), the processing circuit 21 determines whether one or more of the time change ratios γm, γa, and γc exceeds the reference range (S121). Then, if the time change ratios γm, γa, and γc do not exceed the reference range, that is, if the time change ratios γm, γa, and γc are all below the upper limit of the reference range (γmup; γaup; γcup) (S121-No), the processing circuit 21 determines that no abnormal operation or material deterioration has occurred in the electrolysis unit 2 (S120).

[0098] exist Figure 7In the example processing, if one or more of the time change factors γm, γa, and γc exceed the reference range (S121-Yes), the processing circuit 21, etc., determines whether the time change factors (γm, γa, and γc) exceeding the reference range exceed the threshold (γmth; γath; γcth). Then, the processing circuit 21, etc., determines whether one or more of the time change factors (γm, γa, and γc) exceeding the reference range exceed the threshold (γmth; γath; γcth) (S122). If one or more of the time change factors (γm, γa, and γc) exceeding the reference range also exceed the threshold (γmth; γath; γcth) (S122-Yes), the processing circuit 21, etc., determines that insufficient water supply has occurred in the electrolysis unit 2 (S117). Furthermore, if the time variation factor (one or more of γm, γa, γc) exceeding the reference range is below the threshold (γmth; γath; γcth) (S122-No), the processing circuit 21 and others determine that material degradation has occurred in the electrolysis unit 2 (S118).

[0099] This variation also includes Figure 5 Similarly to the aforementioned embodiments of the processing example, when the time-varying factors (γa; γc) of both the anode resistance Ra and the cathode resistance Rc are not lower than the reference range, it is determined whether the time-varying factors (γm; γa; γc) of the membrane resistance Rm, anode resistance Ra, and cathode resistance Rc exceed the threshold (γmth; γath; γcth) and the reference range. Furthermore, in this modified example, the operating status and deterioration state of the electrolysis unit 2 are also determined based on the time changes of the membrane resistance Rm, anode resistance Ra, and cathode resistance Rc. Therefore, the same function and effect as the aforementioned embodiments are achieved in this modified example. That is, in this modified example, by determining the time changes of the resistance components, it is possible to properly monitor the occurrence of operational abnormalities in the electrolysis unit 2, such as excessive heating, overcurrent, and insufficient supply of feedstock.

[0100] Through the Figure 6 Each of the electrolysis units β1 to β6 shown is subjected to interaction with… Figure 7 The same judgment process is applied to the example. For electrolysis unit β1, the judgment is performed in the order of S112-No and S121-No. In S120, it is determined that no operational abnormality or material degradation has occurred in electrolysis unit β1. Furthermore, for each electrolysis unit β2 and β3, the judgment is performed in accordance with... Figure 5The same judgment process was performed for the example. For electrolysis unit β4, the judgment was performed in the order of S112-No, S121-Yes, and S122-Yes. In S117, it was determined that insufficient water supply had occurred in electrolysis unit β4. Then, for each electrolysis unit β5 and β6, the judgment was performed in the order of S112-No, S121-Yes, and S122-No, and it was determined that material degradation had occurred in each of the electrolysis units β5 and β6.

[0101] In the second variation, for each resistance of the membrane resistance Rm, anode resistance Ra, and cathode resistance Rc of electrolysis unit 2, the time changes εm, εa, and εc are calculated and replaced with the time change factors γm, γa, and γc as parameters associated with time changes. In this variation, the time changes εm, εa, and εc, which are parameters associated with time changes, are calculated and used as decision parameters in the decision processing.

[0102] Here, the time change εm of the membrane resistance Rm is calculated as the final value, for example, by measuring the increase or decrease in membrane resistance Rm from the last diagnostic process to the current diagnostic process. For example, in the k-th diagnostic process, the calculated membrane resistance Rm is obtained by subtracting the calculated membrane resistance Rm from the (k-1)-th diagnostic process. Then, the time change εm is calculated by dividing the calculated subtraction value by the calculated membrane resistance Rm from the k-th diagnostic process. If the membrane resistance Rm remains unchanged since the last diagnostic process, the time change εm is 0. Conversely, if the membrane resistance Rm has increased since the last diagnostic process, the time change εm is positive (greater than 0); if the membrane resistance Rm has decreased since the last diagnostic process, the time change εm is negative (less than 0).

[0103] Regarding the time change εa, for example, the anode resistance Ra is used instead of the film resistance Rm, and the time change εa is defined in the same way as the time change εm. Then, regarding the time change εc, for example, the cathode resistance Rc is used instead of the film resistance Rm, and the time change εc is defined in the same way as the time change εm. Furthermore, in one example, in the calculation of the time changes εm, εa, and εc, the processing circuit 21, etc., uses the calculated values ​​of the time changes from each of the most recent reference number Nref (Nref is a natural number greater than 2) diagnostic processes, including real-time diagnostic processes, as temporary values ​​to calculate the final value of the time change. In this case, the processing circuit 21, etc., for each time change εm, εa, and εc, calculates, for example, the average or intermediate value of the calculated values ​​from the most recent reference number Nref diagnostic processes as the final value.

[0104] In this variation, reference ranges are set for each time change quantity εm, εa, and εc. The reference ranges for each of the time change quantities εm, εa, and εc include the value of the corresponding resistance component when it does not change over time, i.e., 0. Therefore, the reference range for the time change quantity εm includes the value of the film resistance Rm when it does not change over time. That is, the reference range for the time change quantity εm, which is above the lower limit εmlow and below the upper limit εmup, includes the value 0. Similarly, the reference range for the time change quantity εa, which is above the lower limit εalow and below the upper limit εaup, includes the value 0, and the reference range for the time change quantity εc, which is above the lower limit εclow and below the upper limit εcup, includes the value 0. In one example, the range of ±Δεm with the value 0 as the median is the reference range for the time change quantity εm, the range of ±Δεa with the value 0 as the median is the reference range for the time change quantity εa, and the range of ±Δεc with the value 0 as the median is the reference range for the time change quantity εc.

[0105] In addition, in this modified example, threshold values ​​εmth, εath, and εcth are set for the time changes εm, εa, and εc, respectively. For each time change εm, εa, and εc, the threshold values ​​(εmth, εath, and εcth) are set higher than the reference range and higher than the upper limit of the reference range (εmup, εaup, and εcup).

[0106] In this modified example, the processing circuit 21, etc., compares the calculation results of the real-time diagnostic processing with a reference range that includes the value when the resistance value does not change with time (i.e., 0), for the time changes (εm; εa; εc) of the membrane resistance Rm, anode resistance Ra, and cathode resistance Rc of the electrolysis unit 2, rather than the time change factors γm, γa, γc, thereby determining the operating condition and deterioration state of the electrolysis unit 2. Furthermore, when determining the operating condition and deterioration state of the electrolysis unit 2, the processing circuit 21, etc., compares the calculation results of the real-time diagnostic processing with a threshold (εmth; εath; εcth) that is set higher than the reference range for each time change εm, εa, εc. The same processing as in any of the aforementioned examples is performed in determining the operating condition and deterioration state of the electrolysis unit 2, for example, comparing with... Figure 5 The same processing as S111 to S120 in the examples, or the same as... Figure 7 The same treatment applies to S111~S115, S117, and S119~S122 in the examples.

[0107] By performing the determination process described above, in this modified example, it is determined whether the time-varying amounts (εa; εc) of the anode resistance Ra and the cathode resistance Rc are below a reference range. Then, if the time-varying amounts (εa; εc) of at least one of the anode resistance Ra and the cathode resistance Rc are below the reference range, it is determined whether the time-varying amount (εm) of the membrane resistance Rm is below the reference range. Then, if the time-varying amount (εm) of the membrane resistance Rm is below the reference range, it is determined that excessive heating has occurred in the electrolysis unit 2; if the time-varying amount (εm) of the membrane resistance Rm is not below the reference range, it is determined that overcurrent has occurred in the electrolysis unit 2. Therefore, in this modified example, similar to the aforementioned embodiments, the occurrence of excessive heating and overcurrent in the electrolysis unit 2 is appropriately determined and monitored.

[0108] Furthermore, in this modified example, if the time-varying amounts (εa; εc) of both the anode resistance Ra and the cathode resistance Rc are not below the reference range, it is determined whether the time-varying amounts (εm; εa; εc) of each of the membrane resistance Rm, anode resistance Ra, and cathode resistance Rc exceed a threshold (εmth; εath; εcth) that is set above the reference range. Then, if the time-varying amounts (εm; εa; εc) of one or more of the membrane resistance Rm, anode resistance Ra, and cathode resistance Rc exceed the threshold (εmth; εath; εcth), it is determined that a water (supply) shortage has occurred in the electrolysis unit 2. Therefore, in this modified example, similar to the aforementioned embodiments, the occurrence of a water shortage as a supply in the electrolysis unit 2 is appropriately determined and monitored.

[0109] Furthermore, in this modified example, when the time-varying amounts (εa; εc) of both the anode resistance Ra and the cathode resistance Rc are not lower than the reference range, it is determined whether the time-varying amounts (εm; εa; εc) of the membrane resistance Rm, anode resistance Ra, and cathode resistance Rc exceed the threshold (εmth; εath; εcth) and the reference range. Then, if the time-varying amounts (εm; εa; εc) of one or more of the membrane resistance Rm, anode resistance Ra, and cathode resistance Rc exceed the reference range, and the time-varying amounts (εm; εa; εc) of all three are below the threshold (εmth; εath; εcth), it is determined that material degradation has occurred in the electrolysis unit 2. Therefore, in this modified example, similar to the aforementioned embodiments, the occurrence of material degradation in the electrolysis unit 2 is appropriately determined and monitored.

[0110] As mentioned earlier, in this modified example, the processing circuit 21 and others determine the operating status and deterioration state of the electrolysis unit 2 based on the time-varying changes of the film resistance Rm, anode resistance Ra, and cathode resistance Rc. Furthermore, by processing the determination based on the time-varying changes of the resistance components, the occurrence of operational anomalies in the electrolysis unit 2, such as excessive heating, overcurrent, and insufficient supply of feedstock, can be accurately detected. Additionally, by processing the determination based on the time-varying changes of the resistance components, the occurrence of material deterioration in the electrolysis unit 2 can be accurately detected. Therefore, in this modified example, the deterioration state and operating status of the electrolysis unit 2 can also be accurately detected by processing the determination based on the time-varying changes of the resistance components.

[0111] Furthermore, the parameters associated with the time variation of the resistance component used as decision parameters are not limited to time variation factors γm, γa, γc or time variation amounts εm, εa, εc. In one variation, as decision parameters, parameters obtained by adding or subtracting a constant to each time variation factor γm, γa, γc or each time variation amount εm, εa, εc can be used, or parameters obtained by multiplying each time variation factor γm, γa, γc or each time variation amount εm, εa, εc by a constant can be used. In another variation, parameters that are standardized from each time variation factor γm, γa, γc or each time variation amount εm, εa, εc can also be used as decision parameters.

[0112] In one variation, the sum or product of the time change factor (γm; γa; γc) and the time change amount (εm; εa; εc) is used as the determination parameter for each of the film resistance Rm, anode resistance Ra, and cathode resistance Rc. Alternatively, in another variation, λm = γm / (γm + γa + γc) can be used as the determination parameter for the film resistance Rm, λa = γa / (γm + γa + γc) for the anode resistance Ra, and λc = γc / (γm + γa + γc) for the cathode resistance Rc. Alternatively, ξm = εm / (εm + εa + εc) can be used as the determination parameter for the film resistance Rm, ξa = εa / (εm + εa + εc) for the anode resistance Ra, and ξc = εc / (εm + εa + εγc) for the cathode resistance Rc.

[0113] Furthermore, regardless of which parameter is used as the judgment parameter, the judgment parameter is a parameter calculated for each resistance of the film resistance Rm, anode resistance Ra, and cathode resistance Rc that is related to the time change. At this time, for each resistance of the film resistance Rm, anode resistance Ra, and cathode resistance Rc, any one of the following is calculated as the judgment parameter: time change factor (γm; γa; γc), parameter corresponding to the time change factor, time change amount (εm; εa; εc), and parameter corresponding to the time change amount. Then, the judgment is performed using the judgment parameter in the same manner as in the above-described implementation, for example, by comparing... Figure 5 The same judgment processing as the example or the same as Figure 7 The same decision processing applies to examples.

[0114] In addition, in the third variation, the timing of inputting diagnostic current to the electrolysis unit 2 is adjusted in the following manner during the measurement of the frequency characteristics of the impedance of the electrolysis unit 2. Figure 8 The flowchart illustrates, for the sake of simplicity, an example of the processing performed by the processing circuit 21 and the like related to inputting a diagnostic current into the electrolysis unit 2 in the third variation. In the calculation of the resistance component of the electrolysis unit 2, this process is repeated over time when a diagnostic current is input into the electrolysis unit 2. Figure 8 The example processing. Additionally, the process is performed while an operating current is input to electrolysis unit 2. Figure 8 The example processing is as follows. Therefore, it is performed with the operating current input to the electrolysis unit 2 and the voltage applied to the electrolysis unit 2 regulated. Figure 8 The processing of examples.

[0115] When it started Figure 8 In the example processing, the processing circuit 21, etc., uses the voltage measurement circuit 8 to acquire the real-time voltage V of the electrolytic unit 2 as a measurement result (S131). Then, the processing circuit 21, etc., determines whether the voltage V of the electrolytic unit 2 is within a specified voltage range (S132). In this modified example, for the voltage V of the electrolytic unit 2, a reference voltage Vref is set under the condition of input operating power (operating current), and a specified voltage range including the reference voltage Vref is set. At this time, for example, the range of ±ΔV with the reference voltage Vref as the midpoint is the specified voltage range.

[0116] When the voltage V is within the specified voltage range (S132 - Yes), the processing circuit 21, etc., controls the operation of the power supply circuit 28 to input a diagnostic current to the electrolysis unit 2 (S133). Accordingly, the diagnostic current is superimposed on the operating current input to the electrolysis unit 2. On the other hand, when the voltage V deviates from the specified voltage range (S132 - No), the processing circuit 21, etc., stops inputting the diagnostic current to the electrolysis unit 2 by controlling the operation of the power supply circuit 28 (S134).

[0117] By conductingFigure 8 In this modified example, the processing circuit 21, etc., causes the diagnostic current to be superimposed on the operating current input to the electrolytic unit 2 when the voltage V of the electrolytic unit 2 is adjusted to a predetermined voltage range. Furthermore, in this modified example, timing data representing the time variation (time history record) of the current and voltage of the electrolytic unit 2 under the condition that the diagnostic current is superimposed on the operating current is used to measure the frequency characteristics of the impedance of the electrolytic unit 2. Therefore, the frequency characteristics of the impedance of the electrolytic unit 2 are measured under the condition that the diagnostic current is superimposed on the operating current.

[0118] Figure 9 A schematic diagram illustrating an example of timing the diagnostic current input to the electrolysis unit 2 in the third variation. Figure 9 The graph shows a time-varying curve with time as the horizontal axis and voltage V of electrolytic unit 2 as the vertical axis, illustrating an example of the time-varying voltage V of electrolytic unit 2. Figure 9 In the example, during time period Y1, the voltage V of electrolysis unit 2 is within the specified voltage range, which is above the lower limit Vref-ΔV and below the upper limit Vref+ΔV. Therefore, during time period Y1, a diagnostic current is input to electrolysis unit 2, and this diagnostic current is superimposed on the operating current input to electrolysis unit 2.

[0119] Furthermore, in time period Y2 following time period Y1, the voltage V of electrolytic unit 2 deviates from the specified voltage range. Therefore, in time period Y2, the diagnostic current input to electrolytic unit 2 is stopped, and the diagnostic current is not superimposed on the operating current input to electrolytic unit 2. Then, in time period Y3 following time period Y2, the voltage V of electrolytic unit 2 is within the specified voltage range. Therefore, in time period Y3, the diagnostic current is input to electrolytic unit 2, and the diagnostic current is superimposed on the operating current input to electrolytic unit 2.

[0120] In this modified example, the same functions and effects as in the embodiments described above are achieved. Furthermore, in this modified example, the diagnostic current is input as described above, so even when the magnitude of the operating power varies over time, the diagnostic current is appropriately input to the electrolysis unit 2 at a timing within the specified voltage range of the voltage V. Therefore, the measurement of the frequency characteristics of the impedance of the electrolysis unit 2 is performed appropriately and simultaneously with the operation of the electrolysis unit 2.

[0121] In the fourth variation, in the electrolysis apparatus 10 having multiple electrolysis units 2_1 to 2_M, the operating status and deterioration status of each of the multiple electrolysis units 2_1 to 2_M are determined in the same manner as in any of the aforementioned embodiments. Figure 10 A schematic diagram showing the structure of the electrolysis apparatus 10 in the fourth modified example is provided. Figure 10As shown, in this modified example, M electrolysis units 2_1 to 2_M are disposed in the electrolysis device 10, and each electrolysis unit 2_1 to 2_M is composed of an electrolysis block or electrolysis module formed by multiple electrolysis cells 3 electrically connected together.

[0122] In this modified example, the processing circuit 21, etc., calculates the film resistance Rm, anode resistance Ra, and cathode resistance Rc for each of the multiple electrolysis units 2_1 to 2_M in the electrolysis apparatus 10 based on the measurement results of the frequency characteristics of the impedance. At this time, the processing circuit 21, etc., calculates the film resistance Rm, anode resistance Ra, and cathode resistance Rc for each electrolysis unit 2_1 to 2_M, for example, by performing a comparison with… Figure 2 The resistance component is calculated using the same processing as in the previous example. Furthermore, in this modified example, the processing circuit 21, etc., determines the operating condition and deterioration state for each of the multiple electrolysis units 2_1 to 2_M based on the time changes of the film resistance Rm, anode resistance Ra, and cathode resistance Rc. At this time, the determination is performed in the same manner as in any of the above embodiments, for example, by performing the same... Figure 5 The same processing as the example or the same Figure 7 The same process is used to determine the outcome of the example.

[0123] In this modified example, the same functions and effects as in the aforementioned embodiments are achieved. Furthermore, in this modified example, for each of the plurality of electrolysis units 2_1 to 2_M provided in the electrolysis apparatus 10, the degradation state and operating condition can be properly grasped by determining the time-varying nature of the resistance components.

[0124] Furthermore, in the aforementioned embodiments, the case where a water electrolysis unit is used as electrolysis unit 2 has been described, but the electrolysis unit 2 that is the subject of diagnosis is not limited to a water electrolysis unit. In one example, a carbon dioxide electrolysis unit is used as electrolysis unit 2 and becomes the subject of diagnosis. In this case, in the carbon dioxide electrolysis unit that is the subject of diagnosis, one or more carbon dioxide electrolysis cells are provided as one or more electrolysis cells 3.

[0125] In the carbon dioxide electrolysis cell constituting the carbon dioxide electrolysis unit, water is supplied to the anode and carbon dioxide to the cathode as feedstocks. Then, when operating power is input to the carbon dioxide electrolysis unit, oxygen is generated from water at the anode and carbon monoxide is generated from carbon dioxide at the cathode. In this example, in the carbon dioxide electrolysis unit 2, which is in operation, the electrolysis of water and carbon dioxide occurs as an electrochemical reaction. Then, the product of water electrolysis, namely oxygen, and the product of carbon dioxide electrolysis, namely carbon monoxide, are recovered.

[0126] When electrolysis unit 2 is a carbon dioxide electrolysis unit, diagnostics are performed in the same manner as in any of the embodiments described above to determine the operating condition and deterioration status. Therefore, when electrolysis unit 2 is a carbon dioxide electrolysis unit, it is possible to properly monitor the occurrence of operational abnormalities in electrolysis unit 2, including overheating, overcurrent, and insufficient feedstock supply. Furthermore, when electrolysis unit 2 is a carbon dioxide electrolysis unit, it is also possible to properly monitor the occurrence of material deterioration in electrolysis unit 2.

[0127] In at least one of the foregoing embodiments or examples, for the electrolysis unit, the membrane resistance caused by the membrane, the anode resistance caused by the anode, and the cathode resistance caused by the cathode are calculated based on the measurement results of the frequency characteristics of the impedance. Then, based on the time changes of the membrane resistance, anode resistance, and cathode resistance, the operating condition and deterioration state of the electrolysis unit are determined. Accordingly, a diagnostic method for an electrolysis unit, a diagnostic method for an electrolysis apparatus, a diagnostic device for an electrolysis unit, an operating system, and a diagnostic procedure for an electrolysis unit can be provided to properly grasp the deterioration state and operating condition of the electrolysis unit.

[0128] Furthermore, the above-described embodiments can be summarized into the following technical solutions.

[0129] Technical Solution 1

[0130] A diagnostic method for an electrolytic unit in which an electrochemical reaction occurs using a supplied substance upon input of electricity, comprising:

[0131] For the electrolysis unit, based on the measurement results of the frequency characteristics of the impedance, the membrane resistance caused by the membrane, the anode resistance caused by the anode, and the cathode resistance caused by the cathode are calculated respectively; and

[0132] The operating status and deterioration state of the electrolysis unit are determined based on the time changes of the membrane resistance, the anode resistance, and the cathode resistance.

[0133] Technical Solution 2

[0134] According to the diagnostic method of technical solution 1, wherein,

[0135] In determining the operating status and deterioration state of the electrolysis unit,

[0136] For each of the membrane resistance, the anode resistance, and the cathode resistance, parameters related to time changes are calculated as decision parameters.

[0137] For each of the membrane resistor, the anode resistor, and the cathode resistor, the calculation result of the determination parameter is compared with a reference range that includes the value when the resistance value does not change over time.

[0138] Technical Solution 3

[0139] According to the diagnostic method of technical solution 2, wherein,

[0140] In determining the operating status and deterioration state of the electrolysis unit,

[0141] If the determination parameter of at least one of the anode resistance and the cathode resistance is below the reference range, and the determination parameter of the membrane resistance is also below the reference range, it is determined that excessive temperature rise has occurred in the electrolysis unit.

[0142] If the determination parameter of at least one of the anode resistance and the cathode resistance is lower than the reference range and the determination parameter of the membrane resistance is not lower than the reference range, it is determined that an overcurrent has occurred in the electrolysis unit.

[0143] Technical Solution 4

[0144] According to the diagnostic method of technical solution 3, among which,

[0145] In determining the operating status and deterioration state of the electrolysis unit,

[0146] Determine whether the determination parameters for the anode resistance and the cathode resistance are each below the reference range.

[0147] If the determination parameter of at least one of the anode resistance and the cathode resistance is lower than the reference range, it is determined whether the determination parameter of the membrane resistance is lower than the reference range, and it is determined which of the excessive heating and the overcurrent has occurred in the electrolysis unit.

[0148] Technical Solution 5

[0149] According to the diagnostic method of any one of technical solutions 2 to 4, wherein,

[0150] In determining the operating status and deterioration state of the electrolysis unit, if at least one of the membrane resistance, the anode resistance, and the cathode resistance exceeds a threshold set above the reference range, it is determined that a shortage of the feedstock has occurred in the electrolysis unit.

[0151] Technical Solution 6

[0152] According to the diagnostic method of technical solution 5, among which,

[0153] In determining the operating status and deterioration state of the electrolysis unit,

[0154] Determine whether the determination parameters for the anode resistance and the cathode resistance are each below the reference range.

[0155] If the determination parameters of both the anode resistance and the cathode resistance are not lower than the reference range, it is determined whether the determination parameters of the membrane resistance, the anode resistance, and the cathode resistance exceed the threshold, and it is determined whether the supply shortage of the feed material has occurred in the electrolysis unit.

[0156] Technical Solution 7

[0157] According to the diagnostic method of technical solution 5, among which,

[0158] In determining the operating status and deterioration state of the electrolysis unit, if at least one of the membrane resistance, anode resistance, and cathode resistance has a determination parameter that exceeds the reference range, and the determination parameters of all three resistances are below the threshold, it is determined that material deterioration has occurred in the electrolysis unit.

[0159] Technical Solution 8

[0160] According to the diagnostic method of technical solution 7, among which,

[0161] In determining the operating status and deterioration state of the electrolysis unit,

[0162] Determine whether the determination parameters for the anode resistance and the cathode resistance are each below the reference range.

[0163] If the determination parameters of both the anode resistance and the cathode resistance are not lower than the reference range, it is determined whether the determination parameters of the film resistance, the anode resistance, and the cathode resistance exceed the reference range and whether they exceed the threshold, and it is determined whether the material degradation has occurred in the electrolysis unit.

[0164] Technical Solution 9

[0165] According to the diagnostic method of any one of technical solutions 2 to 8, wherein,

[0166] In determining the operating status and deterioration state of the electrolysis unit, for each of the membrane resistance, the anode resistance, and the cathode resistance, any one of the following is calculated as the determination parameter: time change factor, parameter corresponding to the time change factor, time change amount, and parameter corresponding to the time change amount.

[0167] Technical Solution 10

[0168] According to the diagnostic method of any one of technical solutions 1 to 9, it also has the following features:

[0169] While the electrolysis unit is running, adjust the voltage of the electrolysis unit;

[0170] With the voltage of the electrolysis unit adjusted to a specified voltage range, a diagnostic current is superimposed on the operating current input to the electrolysis unit; and

[0171] With the diagnostic current superimposed on the operating current, the frequency characteristic of the impedance of the electrolysis unit is measured.

[0172] Technical Solution 11

[0173] A diagnostic method for an electrolysis apparatus having multiple electrolysis units, wherein an electrochemical reaction using a supplied feedstock occurs in each of the multiple electrolysis units upon input of electricity, the diagnostic method comprising:

[0174] By implementing any one of the diagnostic methods from technical solutions 1 to 10 on each of the plurality of electrolysis units, the operating status and the deterioration state of each of the plurality of electrolysis units are determined.

[0175] Technical Solution 12

[0176] A diagnostic device is provided for an electrolysis unit that generates an electrochemical reaction using a supplied substance upon input of electricity. The diagnostic device includes a processor that performs the following operations:

[0177] For the electrolysis unit, based on the measurement results of the frequency characteristics of the impedance, the membrane resistance caused by the membrane, the anode resistance caused by the anode, and the cathode resistance caused by the cathode are calculated respectively.

[0178] The operating status and deterioration state of the electrolysis unit are determined based on the time changes of the membrane resistance, the anode resistance, and the cathode resistance.

[0179] Technical Solution 13

[0180] An operating system having:

[0181] The diagnostic device of technical solution 12; and

[0182] The electrolysis unit is assessed by the processor of the diagnostic device to determine its operating status and deterioration state.

[0183] Technical Solution 14

[0184] According to the operating system of technical solution 13, in which,

[0185] The device comprises multiple electrolysis units, wherein an electrochemical reaction using a supplied feedstock occurs in each of the multiple electrolysis units upon input of electricity.

[0186] The processor of the diagnostic device calculates the membrane resistance, anode resistance, and cathode resistance for each of the plurality of electrolytic units based on the measurement results of the frequency characteristics of the impedance. Furthermore, for each of the plurality of electrolytic units, the processor determines the operating status and the deterioration state based on the time changes of the membrane resistance, anode resistance, and cathode resistance.

[0187] Technical Solution 15

[0188] A storage medium storing a diagnostic program for an electrolysis unit that undergoes an electrochemical reaction using a supplied substance upon electrical input, the diagnostic program causing a computer to perform the following operations:

[0189] For the electrolysis unit, the membrane resistance caused by the membrane, the anode resistance caused by the anode, and the cathode resistance caused by the cathode are calculated based on the measurement results of the frequency characteristics of the impedance; and

[0190] The operating status and deterioration state of the electrolysis unit are determined based on the time changes of the membrane resistance, the anode resistance, and the cathode resistance.

[0191] While several embodiments of the invention have been described, these embodiments are provided by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope or spirit of the invention, as well as in the scope of the claims and their equivalents.

Claims

1. A diagnosis method for an electrolytic unit in which an electrochemical reaction using a supply of a supply material is caused by input of electric power, comprising: calculating, for the electrolytic unit, a membrane resistance caused by a membrane, an anode resistance caused by an anode, and a cathode resistance caused by a cathode, respectively, from a measurement result of a frequency characteristic of impedance; and determining an operation state and a deterioration state of the electrolytic unit from time changes in the membrane resistance, the anode resistance, and the cathode resistance, respectively.

2. The diagnosis method according to claim 1, wherein, in the determination of the operation state and the deterioration state of the electrolytic unit, a parameter associated with a time change is calculated as a determination parameter for each of the membrane resistance, the anode resistance, and the cathode resistance, and a calculation result of the determination parameter is compared with a reference range including a value in a case where a resistance value does not change with time for each of the membrane resistance, the anode resistance, and the cathode resistance.

3. The diagnosis method according to claim 2, wherein, in the determination of the operation state and the deterioration state of the electrolytic unit, it is determined that excessive temperature rise occurs in the electrolytic unit according to a case where the determination parameter of at least one of the anode resistance and the cathode resistance is lower than the reference range and the determination parameter of the membrane resistance is lower than the reference range, and it is determined that overcurrent is generated in the electrolytic unit according to a case where the determination parameter of at least one of the anode resistance and the cathode resistance is lower than the reference range and the determination parameter of the membrane resistance is not lower than the reference range.

4. The diagnosis method according to claim 3, wherein, in the determination of the operation state and the deterioration state of the electrolytic unit, it is determined whether the determination parameter of each of the anode resistance and the cathode resistance is lower than the reference range, and it is determined which of the excessive temperature rise and the overcurrent occurs in the electrolytic unit according to a case where the determination parameter of the membrane resistance is lower than the reference range in a case where the determination parameter of at least one of the anode resistance and the cathode resistance is lower than the reference range.

5. The diagnosis method according to claim 2, wherein, in the determination of the operation state and the deterioration state of the electrolytic unit, it is determined that supply shortage of the supply material occurs in the electrolytic unit according to at least a case where the determination parameter of one or more of the membrane resistance, the anode resistance, and the cathode resistance exceeds a threshold value set higher than the reference range.

6. The diagnosis method according to claim 5, wherein, in the determination of the operation state and the deterioration state of the electrolytic unit, it is determined whether the determination parameter of each of the anode resistance and the cathode resistance is lower than the reference range, and it is determined whether the determination parameter of the membrane resistance is lower than the reference range according to a case where the determination parameter of at least one of the anode resistance and the cathode resistance is lower than the reference range. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ In a case where the determination parameter of both the anode resistance and the cathode resistance is not lower than the reference range, it is determined whether the determination parameter of each of the membrane resistance, the anode resistance, and the cathode resistance exceeds the threshold value, and whether the supply shortage of the supply material occurs in the electrolysis unit.

7. The diagnostic method according to claim 5, wherein, In the determination of the operation state and the deterioration state of the electrolysis unit, in a case where the determination parameter of at least one of the membrane resistance, the anode resistance, and the cathode resistance exceeds the reference range and the determination parameter of all of the membrane resistance, the anode resistance, and the cathode resistance is the threshold value or less, it is determined that material deterioration occurs in the electrolysis unit.

8. The diagnostic method according to claim 7, wherein, In the determination of the operation state and the deterioration state of the electrolysis unit, it is determined whether the determination parameter of each of the anode resistance and the cathode resistance is lower than the reference range, In a case where the determination parameter of both the anode resistance and the cathode resistance is not lower than the reference range, it is determined whether the determination parameter of each of the membrane resistance, the anode resistance, and the cathode resistance exceeds the reference range and whether the threshold value is exceeded, and whether the deterioration of the material occurs in the electrolysis unit.

9. The diagnostic method according to claim 2, wherein, In the determination of the operation state and the deterioration state of the electrolysis unit, any one of a time change rate, a parameter corresponding to the time change rate, a time change amount, and a parameter corresponding to the time change amount is calculated as the determination parameter for each of the membrane resistance, the anode resistance, and the cathode resistance.

10. The diagnostic method according to any one of claims 1 to 9, further comprising: adjusting a voltage of the electrolysis unit in a state where the electrolysis unit is operated; in a state where the voltage of the electrolysis unit is adjusted to a prescribed voltage range, superimposing a diagnostic current on an operation current input to the electrolysis unit; and in a state where the diagnostic current is superimposed on the operation current, measuring the frequency characteristics of the impedance of the electrolysis unit.

11. A diagnosis method for an electrolysis device having a plurality of electrolytic cells, wherein The diagnostic method is provided with: by performing the diagnostic method according to any one of claims 1 to 9 on each of the plurality of electrolysis units, the operation state and the deterioration state are determined for each of the plurality of electrolysis units.

12. A diagnostic device for an electrolysis unit in which an electrochemical reaction using a supplied supply material occurs by input of electric power, the diagnostic device is provided with a processor that performs the following operations: for the electrolysis unit, a membrane resistance caused by a membrane, an anode resistance caused by an anode, and a cathode resistance caused by a cathode are respectively calculated from a measurement result of frequency characteristics of an impedance, The operation state and the deterioration state of the electrolytic unit are determined based on the time change of each of the membrane resistance, the anode resistance, and the cathode resistance.

13. An operation system, comprising: the diagnostic device of claim 12; and The operation state and the deterioration state of the electrolytic unit are determined by the processor of the diagnostic device.

14. The operation system according to claim 13, wherein a plurality of electrolytic units are provided as the electrolytic unit, and an electrochemical reaction using a supplied supply occurs in each of the plurality of electrolytic units by input of electric power, the processor of the diagnostic device calculates the membrane resistance, the anode resistance, and the cathode resistance from the measurement result of the frequency characteristic of the impedance for each of the plurality of electrolytic units, and determines the operation state and the deterioration state for each of the plurality of electrolytic units based on the time change of each of the membrane resistance, the anode resistance, and the cathode resistance.

15. A storage medium storing a diagnostic program for an electrolytic unit in which an electrochemical reaction using a supplied supply occurs by input of electric power, the diagnostic program causing a computer to perform: calculating a membrane resistance caused by a membrane, an anode resistance caused by an anode, and a cathode resistance caused by a cathode from a measurement result of a frequency characteristic of an impedance for the electrolytic unit; and determining an operation state and a deterioration state of the electrolytic unit based on a time change of each of the membrane resistance, the anode resistance, and the cathode resistance.

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