Processing method, processing device, and processing program related to electrochemical cells

Abstract

An embodiment of the present invention provides a processing method related to an electrochemical cell in which at least one of an anode or a cathode has a catalyst. In the processing method, for a target electrochemical cell, it is determined whether the target electrochemical cell is reusable as is, on the basis of the sum of the cell membrane resistance caused by membranes and the cell catalyst resistance caused by the catalyst. In the processing method, when it is determined that the target electrochemical cell is not reusable as is, it is determined whether the target electrochemical cell is renewable without separating the anode and the cathode, on the basis of the cell catalyst resistance.

Description

[Technical Field]

[0001] FIELD OF THE INVENTION An embodiment of the present invention relates to a processing method, a processing device, and a processing program related to an electrochemical cell. [Background technology]

[0002] Electrochemical cells are used that generate electric power through an electrochemical reaction in response to an input of electric power, or that output electric power generated through the electrochemical reaction. In electrochemical cells that receive electric power, an electrochemical reaction such as electrolysis of water occurs in response to the input of electric power, and products of the electrochemical reaction, such as hydrogen, are recovered. In electrochemical cells that output electric power, electric power is generated through an electrochemical reaction in response to a supply of fuel, such as hydrogen, and oxygen, and the generated electric power is supplied.

[0003] After an electrochemical cell has been used, it is reused or recycled. Whether the electrochemical cell is reused or recycled is determined based on the state of the electrochemical cell, including its degradation state. For example, an electrochemical cell with a low degree of degradation is reused. For an electrochemical cell with a high degree of degradation, the anode and cathode are separated, and then the catalyst contained in at least one of the anode and cathode is decomposed, etc., to recover elements or compounds of elements contained in the catalyst. Then, for example, the recovered elements are synthesized to regenerate the catalyst, and the electrochemical cell is recycled.

[0004] Depending on the condition of a used electrochemical cell, the electrochemical cell may be reusable by being regenerated without separating the anode and cathode. Therefore, when determining whether an electrochemical cell can be reused or recycled, it is necessary to appropriately determine whether the electrochemical cell can be regenerated without separating the anode and cathode. It is also necessary to appropriately determine whether the electrochemical cell can be regenerated without separating the anode and cathode, so that the electrochemical cell can be effectively reused in accordance with the condition of the electrochemical cell. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2022-45497 [Patent Document 2] Japanese Patent Publication No. 2014-171335 [Patent Document 3] Japanese Patent Application Publication No. 2014-126532 [Patent Document 4] Japanese Patent Application Publication No. 2017-106889 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a processing method, processing device, and processing program related to an electrochemical cell that enables the electrochemical cell to be effectively reused by determining whether the electrochemical cell should be reused or recycled in accordance with the state of the electrochemical cell. [Means for solving the problem]

[0007] In an embodiment, a processing method is provided for an electrochemical cell in which at least one of the anode and cathode is provided with a catalyst, and an electrochemical reaction occurs in response to the input of electric power, or the cell outputs electric power generated by the electrochemical reaction. The processing method determines whether the target electrochemical cell can be reused as is based on the sum of the cell membrane resistance due to the membrane and the cell catalyst resistance due to the catalyst for the target electrochemical cell. If the processing method determines that the target electrochemical cell cannot be reused as is, it determines whether the target electrochemical cell can be regenerated without separating the anode and cathode based on the cell catalyst resistance. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram illustrating an example of a processing system according to an embodiment. [Figure 2] FIG. 2 is a flowchart illustrating an example of a diagnostic process performed by a processing circuit or the like of the processing device by executing a diagnostic program in the embodiment. [Figure 3] FIG. 3 is a schematic diagram illustrating an example of a process for estimating the cell membrane resistance and the cell catalyst resistance for a certain electrochemical cell in the embodiment. [Figure 4] FIG. 4 is a schematic diagram illustrating an example of a process for estimating the anode catalyst resistance and the cathode catalyst resistance for a certain electrochemical cell in an embodiment, when both the anode and the cathode of the electrochemical cell are provided with catalysts. [Figure 5] FIG. 5 is a flowchart schematically illustrating an example of a determination process performed by a processing circuit or the like of the processing device by executing a determination program in the embodiment. [Figure 6] FIG. 6 is a flowchart schematically illustrating an example of a determination process for the electrochemical cell of FIG. [Figure 7] FIG. 7 is a flowchart schematically illustrating an example of a determination process for the catalyst of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described with reference to the drawings.

[0010] FIG. 1 is a block diagram illustrating an example of a processing system 1 according to an embodiment. In the example illustrated in FIG. 1, the processing system 1 includes an electrochemical module to be processed (target electrochemical module) 2, and a processing device 3. The electrochemical module 2 is used for a predetermined application or for a predetermined device. In one example, the electrochemical module 2 can be connected to a power grid (not shown), and when the electrochemical module 2 is in use, power is input from the power grid to the electrochemical module 2, or power is output from the electrochemical module 2 to the power grid.

[0011] The electrochemical module 2 includes an electrochemical cell 5, and in the example of FIG. 1 , the electrochemical module 2 is provided with a plurality of electrochemical cells 5. When the electrochemical module 2 is composed of a plurality of electrochemical cells 5, the plurality of electrochemical cells 5 are electrically connected to one another in the electrochemical module 2. In this case, in each electrochemical module 2, the plurality of electrochemical cells may be electrically connected in series, or the plurality of electrochemical cells may be electrically connected in parallel. Furthermore, in each electrochemical module 2, both a structure in which a plurality of electrochemical cells are electrically connected in series and a structure in which a plurality of electrochemical cells are electrically connected in parallel may be formed.

[0012] In the electrochemical module 2, each of the electrochemical cells 5 includes an anode and a cathode. In each of the electrochemical cells 5, a membrane such as an ion exchange membrane or an electrolyte membrane is interposed between the anode and the cathode. In each of the electrochemical cells 5, at least one of the anode and the cathode includes a catalyst. In each of the electrochemical cells 5, only one of the anode and the cathode may include a catalyst, or both the anode and the cathode may include a catalyst. In each of the electrochemical cells 5, the anode, the cathode, and the membrane form an electrode group.

[0013] In a configuration in which power is input to the electrochemical module 2, power such as DC power is input to the electrochemical module 2, and thereby power is input to each of the electrochemical cells 5. Then, in each of the electrochemical cells 5, an electrochemical reaction occurs due to the input of power. In this case, products generated by the electrochemical reaction in each of the electrochemical cells 5 of the electrochemical module 2 are collected.

[0014] In one example, the electrochemical module 2 includes water electrolysis cells as electrochemical cells 5. Water is supplied to the electrochemical module 2, which serves as a water electrolysis module. In this case, in each of the electrochemical cells 5 of the electrochemical module 2, hydrogen ions and oxygen are generated at the anode when electric power is input. In each of the electrochemical cells 5, when electric power is input, the hydrogen ions generated at the anode move through the membrane to the cathode, and hydrogen is generated at the cathode. In this example, as described above, in each of the electrochemical cells 5 of the electrochemical module 2, electrolysis of water occurs as an electrochemical reaction when electric power is input. Then, hydrogen, which is a product of the electrolysis of water, is collected.

[0015] In one example, the electrochemical module 2 includes P2C (power to chemicals) cells as electrochemical cells 5. In the electrochemical module 2, water is supplied to the anode of each of the P2C cells, which are electrochemical cells 5, and carbon dioxide is supplied to the cathode of each of the P2C cells. When electric power is input to each of the electrochemical cells 5 of the electrochemical module 2, oxygen is produced from water at the anode, and carbon monoxide is produced from carbon dioxide at the cathode. In this example, as described above, when electric power is input to each of the electrochemical cells 5 of the electrochemical module 2, electrolysis of water and carbon dioxide occurs as an electrochemical reaction. Then, oxygen, which is a product of the electrolysis of water, and carbon monoxide, which is a product of the electrolysis of carbon dioxide, are recovered.

[0016] In a configuration in which electric power is output from the electrochemical module 2, electric power is generated by an electrochemical reaction in each of the electrochemical cells 5. Then, electric power such as DC power generated by the electrochemical reaction in each of the electrochemical cells 5 is output from the electrochemical module 2.

[0017] In one example, the electrochemical module 2 includes fuel cells as electrochemical cells 5. In each of the electrochemical cells 5 of the electrochemical module 2, a fuel such as hydrogen is supplied to the anode, and oxygen is supplied to the cathode. In each of the electrochemical cells 5, an electrochemical reaction occurs due to the supply of fuel and oxygen, and a current is output from the cathode (positive electrode) and input to the anode (negative electrode). As a result, power is generated in each of the electrochemical cells 5. In this example, as described above, oxygen and fuel are supplied to the electrochemical module 2, and power is generated in each of the electrochemical cells 5, and the generated power is output from the electrochemical module 2.

[0018] In the example of FIG. 1 , the processing system 1 includes a measurement circuit 6. The measurement circuit 6 measures parameters related to the electrochemical module 2 to be processed and the electrochemical cells 5 that constitute the electrochemical module 2. The measurement circuit 6 includes an ammeter and a voltmeter. The measurement circuit 6 measures at least one of the current flowing through the entire electrochemical module 2 and the current flowing through each of the electrochemical cells 5 that constitute the electrochemical module 2, as parameters related to the electrochemical module 2 and the electrochemical cells 5. The measurement circuit 6 also measures at least one of the voltage applied to the entire electrochemical module 2 and the voltage applied to each of the electrochemical cells 5 that constitute the electrochemical module 2, as parameters related to the electrochemical module 2 and the electrochemical cells 5.

[0019] In one example, in the electrochemical module 2, the multiple electrochemical cells 5 are electrically connected in series. The measurement circuit 6 measures the overall current of the electrochemical module 2 and also measures the voltage of each of the multiple electrochemical cells 5 that make up the electrochemical module 2. In another example, in the electrochemical module 2, the multiple electrochemical cells 5 are electrically connected in parallel. The measurement circuit 6 measures the overall voltage of the electrochemical module 2 and also measures the current of each of the multiple electrochemical cells 5 that make up the electrochemical module 2. In another example, the measurement circuit 6 may include a temperature sensor or the like and measure either the temperature of the electrochemical module 2 or the temperature of each of the multiple electrochemical cells 5 that make up the electrochemical module 2.

[0020] The processing system 1 includes a diagnostic power supply circuit 7. The power supply circuit 7 is used in diagnosing the electrochemical module 2 and the like, which will be described later. The power supply circuit 7 is capable of outputting a diagnostic current signal, which will be described later.

[0021] The processing device 3 performs processing related to the electrochemical module 2 and the plurality of electrochemical cells 5 that constitute the electrochemical module 2. In one example, the processing device 3 is configured as a computer such as a server, and includes a processing circuit 11 and a storage medium 12. The processing circuit 11 is configured as a processor or an integrated circuit, and the processor that constitutes the processing circuit 11 includes any of a CPU (Central Processing Unit), ASIC (Application Specific Integrated Circuit), microcomputer, FPGA (Field Programmable Gate Array), DSP (Digital Signal Processor), etc. The processing circuit 11 may be configured as a single processor or as multiple processors. The storage medium 12 may be a main storage device such as a memory, or may be an auxiliary storage device. The processing device 3 may be provided with only one storage medium 12, or multiple storage media 12.

[0022] In the processing device 3, the processing circuitry 11 performs processing by executing a program or the like stored in the storage medium 12. The storage medium 12 also stores data or the like used for processing by the processing circuitry 11. In one example, in the processing device 3, the program executed by the processing circuitry 11 may be stored in a computer (server) connected via a network such as the Internet, or in a server in a cloud environment. In this case, the processing circuitry 11 downloads the program via the network.

[0023] 1 , a data management program 15, a diagnostic program 16, and a determination program 17 are stored in the storage medium 12 as programs executed by the processing circuit 11. The processing circuit 11 writes data to the storage medium 12 and reads data from the storage medium 12 by executing the data management program 15. The processing circuit 11 also executes the diagnostic program 16 to perform a diagnostic process, described below, on the electrochemical module 2 and the plurality of electrochemical cells 5 that constitute the electrochemical module 2. The processing circuit 11 also executes the determination program 17 to perform a determination process, described below, on the electrochemical module 2 and the plurality of electrochemical cells 5 that constitute the electrochemical module 2.

[0024] In one example, the processing device 3 is configured from multiple computers such as multiple servers, and the processors of the multiple computers work together to perform the diagnostic processing and determination processing described below. In this case, for example, the diagnostic processing described below is performed by one of the multiple computers, and the determination processing described below is performed by another computer among the multiple computers other than the computer that performs the diagnostic processing. When the processing device 3 is configured from multiple computers, the multiple computers that make up the processing device 3 can communicate with each other wirelessly or via wires.

[0025] In another example, at least a part of the processing device 3 is configured from a cloud server in a cloud environment. The infrastructure of the cloud environment is configured from a virtual processor such as a virtual CPU and a cloud memory. When at least a part of the processing device 3 is configured from a cloud server, at least a part of the diagnostic processing and determination processing, which will be described later, is performed by the virtual processor. Furthermore, the program executed by the virtual processor and the data used in the processing by the virtual processor are stored in the cloud memory.

[0026] The processing device 3 also includes a communication interface 13. The processing circuit 11 communicates with devices external to the processing device 3 via the communication interface 13. Communication via the communication interface 13 is performed wirelessly or via a wired connection. The processing circuit 11 and the like of the processing device 3 receive information indicating measurement results for parameters related to the electrochemical module 2 and the electrochemical cell 5 from the measurement circuit 6 via the communication interface 13. The processing circuit 11 and the like also transmit commands related to drive control of the power supply circuit 7 to a power supply device (not shown) in which the power supply circuit 7 is installed, via the communication interface 13.

[0027] In one example, the processing device 3 may be provided with a user interface (not shown). In this case, various operations, including operations related to the electrochemical module 2 and the electrochemical cell 5, are input to the user interface by users of the processing device 3 and the processing system 1, etc. For this reason, the user interface is provided with any of a button, a mouse, a touch panel, a keyboard, etc. as an operation unit through which operations are input by users, etc. The user interface is also provided with a notification unit that notifies users of information related to the electrochemical module 2 and the electrochemical cell 5. The notification unit notifies users of information by displaying a screen, emitting a sound, etc. Note that the user interface may be provided separately from the computer, etc. that constitutes the processing device 3.

[0028] In this embodiment, when an electrochemical module 2 including a plurality of electrochemical cells 5 is in use, the electrochemical module 2 and each of the electrochemical cells 5 are periodically diagnosed. The diagnosis of the electrochemical module 2 and the electrochemical cells 5 is performed by the processing circuit 11 and the like executing a diagnostic program 16. FIG. 2 is a flowchart showing an example of diagnostic processing performed by the processing circuit 11 and the like by executing the diagnostic program 16. The example processing of FIG. 2 is performed periodically when the electrochemical module 2 is in use. Furthermore, the example processing of FIG. 2 is performed when the temperatures of the electrochemical module 2 and the electrochemical cells 5, i.e., the environmental temperature of the environment in which the electrochemical module 2 is placed, are within a specified temperature range. The specified temperature range is, for example, 15°C or higher and 90°C or lower, and preferably 50°C or higher and 80°C or lower.

[0029] 2 is started, the processing circuit 11 and the like start inputting a diagnostic current signal to the electrochemical module 2 by, for example, controlling the driving of the diagnostic power supply circuit 7 (S101). As a result, the diagnostic current signal is input to the electrochemical module 2 and each of the electrochemical cells 5 that make up the electrochemical module 2. In one example, a pseudo-random pulse signal such as an M-sequence signal is input to the electrochemical module 2 as the diagnostic current signal. The pseudo-random pulse signal input to the electrochemical module 2 includes multiple types of pulses that have different pulse widths.

[0030] In another example, an AC current whose current value changes periodically is input to the electrochemical module 2 as a diagnostic current signal. In this case, the AC current is input to the electrochemical module 2 in any waveform, such as a sine wave, a triangular wave, or a sawtooth wave. In this example, the processing circuit 11 and the like can adjust the frequency of the AC current input to the electrochemical module 2 by controlling the driving of the diagnostic power supply circuit 7. Then, the processing circuit 11 and the like input the AC current that serves as the diagnostic current signal to the electrochemical module 2 in a state in which the AC current changes over time to multiple frequencies.

[0031] Then, while the diagnostic current signal is being input to the electrochemical module 2, the processing circuit 11 and the like cause the measurement circuit 6 to measure parameters related to the electrochemical module 2 and the electrochemical cell 5, thereby acquiring diagnostic measurement data (S102). The diagnostic measurement data is generated based on the measurement results by the measurement circuit 6 while the diagnostic current signal is being input to the electrochemical module 2. The diagnostic measurement data indicates, for example, the time changes (time history) of the current of the electrochemical module 2 and the currents of the electrochemical cells 5 while the diagnostic current signal is being input to the electrochemical module 2. The diagnostic measurement data also indicates, for example, the time changes (time history) of the voltage of the electrochemical module 2 and the voltages of the electrochemical cells 5 while the diagnostic current signal is being input to the electrochemical module 2.

[0032] Note that a diagnostic current signal may be input to the electrochemical module 2 while an electrochemical reaction is occurring in the electrochemical module 2 due to the input of electric power, or while electric power generated by the electrochemical reaction is being output from the electrochemical module 2. In this case, the diagnostic current signal is superimposed on the current input to the electrochemical module 2 to cause the electrochemical reaction, or on the current output from the electrochemical module 2 due to the occurrence of the electrochemical reaction. Therefore, measurement data for diagnosis is measured in parallel with the operation of the electrochemical module 2.

[0033] When the measurement ends with the diagnostic current signal being input to the electrochemical module 2 and the processing circuit 11 etc. acquires the diagnostic measurement data, the processing circuit 11 etc. stops the input of the diagnostic current signal to the electrochemical module 2 by, for example, controlling the drive of the diagnostic power supply circuit 7 (S103). As a result, the diagnostic current signal is no longer input to the electrochemical module 2 and each of the electrochemical cells 5 that make up the electrochemical module 2.

[0034] Then, the processing circuit 11 etc. analyzes the diagnostic measurement data to measure the frequency characteristics of impedance for the electrochemical module 2 and each of the electrochemical cells 5 that make up the electrochemical module 2 (S104). Here, the process of measuring the frequency characteristics of impedance for one electrochemical cell 5 will be described.

[0035] In measuring the frequency characteristics of the impedance of the electrochemical cell 5, current time series data showing the time change in the current of the electrochemical cell 5 while the diagnostic current signal is input to the electrochemical module 2 is Fourier transformed to generate current spectrum data showing the frequency characteristics of the current of the electrochemical cell 5. Then, voltage time series data showing the time change in the voltage of the electrochemical cell 5 while the diagnostic current signal is input to the electrochemical module 2 is Fourier transformed to generate voltage spectrum data showing the frequency characteristics of the voltage of the electrochemical cell 5.

[0036] Then, an operation is performed using the current spectrum data and the voltage spectrum data of the electrochemical cell 5 to calculate impedance spectrum data that indicates the frequency characteristics of the impedance of the electrochemical cell 5. The impedance spectrum data of the electrochemical cell 5 is calculated, for example, by dividing the voltage spectrum data of the electrochemical cell 5 by the current spectrum data of the electrochemical cell 5. The impedance spectrum data of the electrochemical cell 5 indicates the impedance of the electrochemical cell 5 at each of a plurality of frequencies.

[0037] A method for calculating the frequency characteristics of the impedance of a battery using current time-series data on the battery current and voltage time-series data on the battery voltage is disclosed in Patent Document 3 (Japanese Patent Laid-Open Publication No. 2014-126532). In the embodiment, etc., the frequency characteristics of the impedance of the electrochemical cell 5 may be calculated in the same manner as the calculation of the frequency characteristics of the impedance of the battery in Patent Document 3. In this case, the processing circuit 11 etc. calculates an autocorrelation function of the current spectrum data of the electrochemical cell 5 and also calculates a cross-correlation function between the current spectrum data and voltage spectrum data of the electrochemical cell 5. Then, the processing circuit 11 etc. calculates the frequency characteristics of the impedance of the electrochemical cell 5 using the calculated autocorrelation function and cross-correlation function.

[0038] Furthermore, when AC currents at multiple frequencies are input to the electrochemical module 2 as diagnostic current signals, the processing circuit 11 and the like calculate the impedance of the electrochemical cell 5 for each of the multiple frequencies based on the current and voltage values ​​of the electrochemical cell 5 indicated by measurement data and the like. In this case, for example, the impedance of the electrochemical cell 5 is calculated by dividing the voltage value of the electrochemical cell 5 by the current value for each of the multiple frequencies. In this way, the frequency characteristics of the impedance of the electrochemical cell 5, which indicate the impedance of the electrochemical cell 5 at each of the multiple frequencies, are calculated.

[0039] The impedance frequency characteristics of the other electrochemical cells 5 constituting the electrochemical module 2 are also measured using one of the methods described above. The impedance frequency characteristics of the electrochemical module 2 are also measured using current time series data showing the time change in the current of the electrochemical module 2 while a diagnostic current signal is being input to the electrochemical module 2, and voltage time series data showing the time change in the voltage of the electrochemical module 2 while a diagnostic current signal is being input to the electrochemical module 2. In this case, the impedance frequency characteristics of the electrochemical module 2 are calculated in the same manner as the impedance frequency characteristics of the electrochemical cell 5. That is, the impedance frequency characteristics of the electrochemical module 2 are measured using one of the methods described above.

[0040] Then, the processing circuit 11 etc. estimates, for each of the electrochemical cells 5, a cell membrane resistance Rc1, which is a resistance component due to a membrane such as an ion exchange membrane, and a cell catalyst resistance Rc2, which is a resistance component due to a catalyst (S105). The processing circuit 11 etc. also estimates, for the electrochemical module 2, a module membrane resistance Rm1, which is a resistance component due to the membrane, and a module catalyst resistance Rm2, which is a resistance component due to the catalyst (S106). For each of the electrochemical cells 5, the cell membrane resistance Rc1 and the cell catalyst resistance Rc2 are calculated based on the measurement results of the impedance frequency characteristics. For the electrochemical module 2, the module membrane resistance Rm1 and the module catalyst resistance Rm2 are also calculated based on the measurement results of the impedance frequency characteristics.

[0041] FIG. 3 illustrates an example of a process for estimating the cell membrane resistance Rc1 and the cell catalyst resistance Rc2 for a given electrochemical cell 5. FIG. 3 shows a complex impedance plot (Cole-Cole plot). As shown in FIG. 3, in the complex impedance plot, the horizontal axis represents the real component Zre of the impedance, and the vertical axis represents the imaginary component −Zim of the impedance. In addition, in the example of FIG. 3, the frequency characteristics of the impedance in a state εa for the electrochemical cell 5 are shown by a dashed line, and the frequency characteristics of the impedance in a state εb different from the state εa are shown by a solid line.

[0042] As shown in FIG. 3, a complex impedance plot showing the frequency characteristics of the impedance of the electrochemical cell 5 forms an arc portion A that is convex on the negative side of the imaginary component of the impedance. The arc portion A has a vertex T of the convex shape, where the imaginary component of the impedance is negative. Furthermore, on the complex impedance plot, an intersection C where the arc portion A intersects with the horizontal axis, which is the axis of the real component, is present on the high-frequency side of the vertex T of the convex shape. In the example of FIG. 3, the value (positive value) of the real component of the impedance at the intersection C of the complex impedance plot is calculated as the cell membrane resistance Rc1 of the electrochemical cell 5. The diameter of the arc portion A is calculated as the cell catalyst resistance Rc2 of the electrochemical cell 5.

[0043] In the example of FIG. 3, for state εa, the resistance value Rc1a of the cell membrane resistance Rc1 and the resistance value Rc2a of the cell catalyst resistance are shown. For state εb, the resistance value Rc1b of the cell membrane resistance Rc1 and the resistance value Rc2b of the cell catalyst resistance are shown. In the electrochemical cell 5, the higher the degree of membrane degradation, the higher the cell membrane resistance Rc1. Furthermore, for the electrochemical cell 5, the higher the degree of catalyst degradation, the higher the cell catalyst resistance Rc2. In the example of FIG. 3, the resistance value Rc1b is higher than the resistance value Rc1a, and the resistance value Rc2b is higher than the resistance value Rc2a. Therefore, in state εb, the degree of membrane degradation of the electrochemical cell 5 is higher than in state εa, and the degree of catalyst degradation of the electrochemical cell 5 is higher. The cell membrane resistance Rc1 and the cell catalyst resistance Rc2 of the other electrochemical cells 5 constituting the electrochemical module 2 are calculated in the same manner as described above.

[0044] Furthermore, for the electrochemical module 2, the module membrane resistance Rm1 and the module catalyst resistance Rm2 are estimated using a complex impedance plot that shows the frequency characteristics of the impedance of the electrochemical module 2. In this case, the module membrane resistance Rm1 is calculated from the complex impedance plot for the electrochemical module 2 in the same manner as the cell membrane resistance Rc1 was calculated in the example of FIG. 3. Then, the module catalyst resistance Rm2 is calculated from the complex impedance plot for the electrochemical module 2 in the same manner as the cell catalyst resistance Rc2 was calculated in the example of FIG.

[0045] In the electrochemical module 2, the module membrane resistance Rm1 increases as the degree of degradation of the membrane in the electrochemical cell 5 constituting the electrochemical module 2 increases. Also, in the electrochemical module 2, the module catalyst resistance Rm2 increases as the degree of degradation of the catalyst in the electrochemical cell 5 constituting the electrochemical module 2 increases.

[0046] Then, the processing circuit 11 etc. estimates at least one of the anode catalyst resistance Rα, which is a resistance component caused by the anode catalyst, and the cathode catalyst resistance Rβ, which is a resistance component caused by the cathode catalyst, for each electrochemical cell 5 (S107). Below, the process of estimating the anode catalyst resistance Rα and / or the cathode catalyst resistance Rβ for one electrochemical cell 5 will be described. In the embodiment etc., in the diagnostic process, the anode catalyst resistance Rα and / or the cathode catalyst resistance Rβ for other electrochemical cells 5 are also estimated in the same manner as the process below.

[0047] When only the anode in the electrochemical cell 5 is equipped with a catalyst, the cell catalyst resistance Rc2 estimated in S105 is calculated as the resistance value of the anode catalyst resistance Rα of the electrochemical cell 5. In this case, the cathode of the electrochemical cell 5 is not equipped with a catalyst, so the cathode catalyst resistance Rβ of the electrochemical cell 5 is not estimated. Also, when only the cathode in the electrochemical cell 5 is equipped with a catalyst, the cell catalyst resistance Rc2 estimated in S105 is calculated as the resistance value of the cathode catalyst resistance Rβ of the electrochemical cell 5. In this case, the anode of the electrochemical cell 5 is not equipped with a catalyst, so the anode catalyst resistance Rα of the electrochemical cell 5 is not estimated.

[0048] 4 illustrates an example of a process for estimating the anode catalyst resistance Rα and the cathode catalyst resistance Rβ for a given electrochemical cell 5 when both the anode and cathode of the electrochemical cell 5 are provided with catalysts. A complex impedance plot is shown in FIG. 4. The frequency characteristics of the impedance of the electrochemical cell 5 are shown by a solid line.

[0049] In one process shown in Figure 4, the aforementioned arc portion A shown as the impedance of the electrochemical cell 5 in the complex impedance plot is separated into the anode impedance due to the anode catalyst, etc., and the cathode impedance due to the cathode catalyst, etc. As a result, in the complex impedance plot, the arc portion A showing the impedance of the electrochemical cell 5 is separated into the arc portion Aα showing the anode impedance, and the arc portion Aβ showing the cathode impedance. In Figure 4, the arc portion Aα showing the anode impedance is shown by a dashed line, and the arc portion Aβ showing the cathode impedance is shown by a dashed line.

[0050] The diameter of the arc portion Aα is calculated as the anode catalyst resistance Rα of the electrochemical cell 5, and the diameter of the arc portion Aβ is calculated as the cathode catalyst resistance Rβ of the electrochemical cell 5. The arc portion Aα is convex on the negative side of the imaginary component of the impedance, and the imaginary component of the impedance takes a negative value at the apex Tα of the convex shape of the arc portion Aα. The arc portion Aβ is also convex on the negative side of the imaginary component of the impedance, and the imaginary component of the impedance takes a negative value at the apex Tβ of the convex shape of the arc portion Aβ.

[0051] The process of separating the arc portion A into the arc portions Aα and Aβ is performed using, for example, measurement results of the frequency characteristics of the impedance of the electrochemical cell 5, such as a complex impedance plot, and an equivalent circuit model of the electrochemical cell 5. The equivalent circuit model of the electrochemical cell 5 is stored in a storage medium 12 or the like, and circuit parameters (electrical characteristic parameters) including resistance components of the electrochemical cell 5 are set in the equivalent circuit model. The circuit parameters set in the equivalent circuit model include an anode catalyst resistance Rα and a cathode catalyst resistance Rβ. The equivalent circuit model also indicates the relationship between the set circuit parameters and the impedance of the electrochemical cell 5, and indicates, for example, a relational equation for calculating the impedance of the electrochemical cell 5 using the circuit parameters and frequency.

[0052] In calculating the anode catalytic resistance Rα and the cathode catalytic resistance Rβ of the electrochemical cell 5, the processing circuit 11 and the like perform fitting calculations using, for example, the relationship between the circuit parameters and impedance shown in the equivalent circuit model and measurement results of the impedance frequency characteristics of the electrochemical cell 5. At this time, the fitting calculations are performed using the circuit parameters set in the equivalent circuit model including the anode catalytic resistance Rα and the cathode catalytic resistance Rβ as variables to calculate the circuit parameters that serve as variables. Furthermore, in the fitting calculations, values ​​of the circuit parameters that serve as variables are calculated so that the difference between the calculated value calculated using the relationship shown in the equivalent circuit model and the measured value that is the measurement result is as small as possible, at each of the multiple frequencies at which the impedance is measured. By calculating the circuit parameters through the fitting calculations, the anode catalytic resistance Rα and the cathode catalytic resistance Rβ of the electrochemical cell 5 are calculated.

[0053] Note that a method of performing fitting calculations using measurement results of the frequency characteristics of the impedance of a battery and the relationship between the impedance and circuit parameters (circuit constants) shown in an equivalent circuit model of the battery, calculating values ​​of the circuit parameters set in the equivalent circuit model, and calculating the resistance components of the battery is disclosed in Patent Document 4 (Japanese Patent Laid-Open Publication No. 2017-106889). In embodiments, the anode catalyst resistance Rα and cathode catalyst resistance Rβ of the electrochemical cell 5 may be calculated in the same manner as the calculation of the resistance components of the battery in Patent Document 4.

[0054] In this embodiment, a determination is made on the electrochemical module 2 and the electrochemical cells 5 constituting the electrochemical module 2 using a diagnosis result such as the example diagnostic process of Fig. 2. The determination on the electrochemical module 2 and the electrochemical cells 5 is made by the processing circuit 11 and the like executing a determination program 17. Fig. 5 is a flowchart showing an example of the determination process performed by the processing circuit 11 and the like by executing the determination program 17. The example process of Fig. 5 is performed, for example, every time a new diagnosis is performed on the electrochemical module 2 and the diagnosis result is updated.

[0055] 5 uses the estimation results from the above-described diagnostic process. That is, in the determination process, determination is made using the estimation results of the module membrane resistance Rm1 and module catalyst resistance Rm2 of the electrochemical module 2, and the estimation results of the cell membrane resistance Rc1, cell catalyst resistance Rc2, anode catalyst resistance Rα, and cathode catalyst resistance Rβ of each of the electrochemical cells 5, as estimation results from the diagnosis during use of the electrochemical module 2.

[0056] In one example, the judgment process is performed using only the diagnostic results from the most recent diagnosis. In this case, for estimated parameters including module catalyst resistance Rm2 and cell catalyst resistance Rc2, estimated values ​​from the most recent diagnosis are used in the judgment process described below. In another example, the judgment process is performed using diagnostic results from multiple diagnoses including the most recent diagnosis. In this case, for estimated parameters including module catalyst resistance Rm2 and cell catalyst resistance Rc2, the average or weighted average of estimated values ​​from multiple diagnoses is used in the judgment process described below.

[0057] 5 begins, the processing circuit 11, etc. determine whether the sum Rm0 of the module membrane resistance Rm1 and the module catalyst resistance Rm2 of the electrochemical module (target electrochemical module) 2 is equal to or greater than a threshold value Rm0th (S111). If the sum Rm0 is less than the threshold value Rm0th (S111-No), the processing circuit 11, etc. determine to continue using the electrochemical module 2 for a predetermined purpose or in a predetermined device (S112). On the other hand, if the sum Rm0 is equal to or greater than the threshold value Rm0th (S111-Yes), the processing circuit 11, etc. determine to end use of the electrochemical module 2 for a predetermined purpose or in a predetermined device (S113). The electrochemical module 2 is then determined to be a used electrochemical module 2 whose use for a predetermined purpose or in a predetermined device has ended.

[0058] In one example, instead of the process of S111, the processing circuit 11 etc. determines whether the amount of change (amount of increase) in the sum Rm0 from a predetermined point in time, such as the start of use of the electrochemical module 2, is equal to or greater than a threshold. If the amount of change in the sum Rm0 is smaller than the threshold, the processing circuit 11 etc. determines to continue using the electrochemical module 2. On the other hand, if the amount of change in the sum Rm0 is equal to or greater than the threshold, the processing circuit 11 etc. determines to end use of the electrochemical module 2. As described above, in the processes of S111 to S113 etc., it is determined whether to continue using the electrochemical module 2 based on the sum Rm0 of the module membrane resistance Rm1 and the module catalyst resistance Rm2 of the electrochemical module 2.

[0059] When ending use of the electrochemical module 2, the processing circuit 11, etc. determine whether the module catalyst resistance Rm2 of the electrochemical module 2 is equal to or greater than a threshold value Rm2th (S114). If the module catalyst resistance Rm2 is less than the threshold value Rm2th (S114-No), the processing circuit 11, etc. determine that it is not necessary to separate the multiple electrochemical cells 5 that make up the electrochemical module 2 from one another. The processing circuit 11, etc. then determine that the electrochemical module 2 can be regenerated without separating the multiple electrochemical cells 5 from one another (S115). On the other hand, if the module catalyst resistance Rm2 is equal to or greater than the threshold value Rm2th (S114-Yes), the processing circuit 11, etc. determine that it is necessary to separate the multiple electrochemical cells 5 from one another (S116). The processing circuit 11, etc. then determine that it is not possible to regenerate the electrochemical module 2 without separating the multiple electrochemical cells 5 from one another.

[0060] In one example, instead of the process of S114, the processing circuit 11 etc. determines whether the amount of change (amount of increase) in the module catalyst resistance Rm2 from a predetermined point in time, such as when the electrochemical module 2 starts to be used, is equal to or greater than a threshold. If the amount of change in the module catalyst resistance Rm2 is smaller than the threshold, the processing circuit 11 etc. determines that it is not necessary to separate the multiple electrochemical cells 5 from each other. On the other hand, if the amount of change in the module catalyst resistance Rm2 is equal to or greater than the threshold, the processing circuit 11 etc. determines that it is necessary to separate the multiple electrochemical cells 5 from each other. As described above, in the processes of S114 to S116 etc., it is determined based on the module catalyst resistance Rm2 of the electrochemical module 2 whether the electrochemical module 2 can be regenerated without separating the multiple electrochemical cells 5 from each other.

[0061] If it is determined that the electrochemical module 2 cannot be restored without separating the multiple electrochemical cells 5 from one another, the processing circuit 11 etc. executes a determination process for each electrochemical cell 5 (S117). The determination process of S117 is performed with any one of the electrochemical cells 5 constituting the electrochemical module 2 as the target electrochemical cell to be processed. When the determination process of S117 is completed for one electrochemical cell 5, the processing circuit 11 etc. determines whether the determination process of S117 has been completed for all electrochemical cells 5 constituting the electrochemical module 2 (S118).

[0062] If the determination process has not been completed for one or more electrochemical cells 5 (S118-No), the process returns to S117. Then, the processing circuit 11 etc. performs the determination process of S117 for any one of the electrochemical cells 5 for which the determination process has not been performed. Therefore, if it is determined that multiple electrochemical cells 5 need to be separated from each other, the processing circuit 11 etc. perform the determination process of S117 for each of all of the electrochemical cells 5 that make up the electrochemical module 2.

[0063] Fig. 6 is a flowchart showing an example of the determination process for a single electrochemical cell 5, which is the process of S117 in Fig. 5. The example process in Fig. 6 is performed with any one of the electrochemical cells 5 constituting the electrochemical module 2 as the target electrochemical cell to be processed.

[0064] 6 starts, the processing circuit 11 etc. determines whether the sum Rc0 of the cell membrane resistance Rc1 and the cell catalyst resistance Rc2 of the electrochemical cell (target electrochemical cell) 5 is equal to or greater than a threshold Rc0th (S121). If the sum Rc0 is smaller than the threshold Rc0th (S121-No), the processing circuit 11 etc. determines that the electrochemical cell 5 can be reused as is (S122). On the other hand, if the sum Rc0 is equal to or greater than the threshold Rc0th (S121-Yes), the processing circuit 11 etc. determines that the electrochemical cell 5 cannot be reused as is (S123).

[0065] In one example, instead of the process of S121, the processing circuit 11 etc. determines whether the amount of change (amount of increase) in the sum Rc0 from a predetermined point in time, such as the start of use of the electrochemical module 2, is equal to or greater than a threshold value. If the amount of change in the sum Rc0 is smaller than the threshold value, the processing circuit 11 etc. determines that the electrochemical cell 5 can be reused as is. On the other hand, if the amount of change in the sum Rc0 is equal to or greater than the threshold value, the processing circuit 11 etc. determines that the electrochemical cell 5 cannot be reused as is. As described above, in the processes of S121 to S123 etc., it is determined whether the electrochemical cell 5 can be reused as is based on the sum Rc0 of the cell membrane resistance Rc1 and the cell catalyst resistance Rc2 of the electrochemical cell (target electrochemical cell) 5.

[0066] If it is determined that the electrochemical cell 5 cannot be reused as is, the processing circuit 11 etc. determines whether the cell catalyst resistance Rc2 of the electrochemical cell 5 is equal to or greater than a threshold value Rc2th (S124). If the cell catalyst resistance Rc2 is less than the threshold value Rc2th (S124-No), the processing circuit 11 etc. determines that separation of the anode and cathode in the electrochemical cell 5 is not necessary. Then, the processing circuit 11 etc. determines that the electrochemical cell 5 can be regenerated without separating the anode and cathode (S125). Therefore, it is determined that the electrochemical cell 5 can be regenerated without separating the catalyst contained in at least one of the anode and cathode.

[0067] On the other hand, if the cell catalyst resistance Rc2 is equal to or greater than the threshold value Rc2th (S124—Yes), the processing circuit 11 etc. determines that it is necessary to separate the anode and the cathode in the electrochemical cell 5 (S126). Then, the processing circuit 11 etc. determines that the electrochemical cell 5 cannot be regenerated without separating the anode and the cathode. Therefore, it is determined that the electrochemical cell 5 cannot be regenerated without separating the catalyst contained in at least one of the anode and the cathode.

[0068] In one example, instead of the process of S124, the processing circuit 11 etc. determines whether the amount of change (increase) in the cell catalyst resistance Rc2 from a predetermined point in time, such as when the electrochemical module 2 was first used, is equal to or greater than a threshold value. If the amount of change in the cell catalyst resistance Rc2 is smaller than the threshold value, the processing circuit 11 etc. determines that separation of the anode and cathode in the electrochemical cell (target electrochemical cell) 5 is unnecessary. On the other hand, if the amount of change in the cell catalyst resistance Rc2 is equal to or greater than the threshold value, the processing circuit 11 etc. determines that separation of the anode and cathode in the electrochemical cell 5 is necessary. As described above, in the processes of S124 to S126 etc., it is determined based on the cell catalyst resistance Rc2 of the electrochemical cell (target electrochemical cell) 5 whether the electrochemical cell 5 can be regenerated without separating the anode and cathode. In other words, it is determined based on the cell catalyst resistance Rc2 whether the electrochemical cell 5 can be regenerated without separating the catalyst from the electrode group.

[0069] If it is determined that the electrochemical cell 5 cannot be regenerated without separating the anode and the cathode, the processing circuit 11 and the like execute a determination process for the catalyst (S127). The determination process of S127 is performed for the electrochemical cell 5 determined to be unable to be regenerated without separating the catalyst. Fig. 7 is a flowchart showing an example of the determination process for the catalyst, which is the process of S127 in Fig. 6.

[0070] 7 starts, the processing circuit 11 etc. determines whether or not a catalyst is present in the anode of the electrochemical cell (target electrochemical cell) 5 (S131). In one example, information about the anode of the electrochemical cell 5 is stored in the storage medium 12, and the processing circuit 11 etc. makes the determination in S131 based on the stored information about the anode. If a catalyst is present in the anode (S131-Yes), the processing circuit 11 etc. determines whether or not the anode catalyst resistance Rα is equal to or greater than a threshold value Rαth (S132).

[0071] If the anode catalyst resistance Rα is smaller than the threshold value Rαth (S132-No), the processing circuit 11 etc. determines that decomposition of the anode catalyst is not necessary. That is, the processing circuit 11 etc. determines that the anode catalyst can be reused as is (S133). On the other hand, if the anode catalyst resistance Rα is equal to or greater than the threshold value Rαth (S132-Yes), the processing circuit 11 etc. determines that the anode catalyst needs to be decomposed and that recycling by decomposition of the anode catalyst will be performed (S134). That is, it is determined that the anode catalyst cannot be reused as is.

[0072] In one example, instead of the process of S132, the processing circuit 11 etc. determines whether the amount of change (amount of increase) in the anode catalyst resistance Rα from a predetermined point in time, such as when the electrochemical module 2 was first used, is equal to or greater than a threshold value. If the amount of change in the anode catalyst resistance Rα is smaller than the threshold value, the processing circuit 11 etc. determines that decomposition of the anode catalyst is unnecessary. On the other hand, if the amount of change in the anode catalyst resistance Rα is equal to or greater than the threshold value, the processing circuit 11 etc. determines that decomposition of the anode catalyst is necessary. As described above, in the processes of S132 to S134 etc., it is determined whether the anode catalyst can be reused as is based on the anode catalyst resistance Rα of the electrochemical cell (target electrochemical cell) 5.

[0073] After the process of S133 or S134 is performed, the process proceeds to S135. If no catalyst is present at the anode of the electrochemical cell 5 (S131-No), the processes of S132 to S134 are not performed and the process proceeds to S135.

[0074] Then, the processing circuit 11 etc. determines whether or not a catalyst is present at the cathode of the electrochemical cell (target electrochemical cell) 5 (S135). In one example, information about the cathode of the electrochemical cell 5 is stored in the storage medium 12, and the processing circuit 11 etc. makes the determination of S135 based on the stored information about the cathode. If a catalyst is present at the anode (S135-Yes), the processing circuit 11 etc. determines whether or not the cathode catalyst resistance Rβ is equal to or greater than a threshold value Rβth (S136).

[0075] If the cathode catalyst resistance Rβ is smaller than the threshold value Rβth (S136-No), the processing circuit 11 etc. determines that decomposition of the cathode catalyst is not necessary. That is, the processing circuit 11 etc. determines that the cathode catalyst can be reused as is (S137). On the other hand, if the cathode catalyst resistance Rβ is equal to or greater than the threshold value Rβth (S136-Yes), the processing circuit 11 etc. determines that the cathode catalyst needs to be decomposed and that recycling by decomposition of the cathode catalyst will be performed (S138). That is, it is determined that the cathode catalyst cannot be reused as is.

[0076] In one example, instead of the process of S136, the processing circuit 11 etc. determines whether the amount of change (amount of increase) in the cathode catalyst resistance Rβ from a predetermined point in time, such as when the electrochemical module 2 begins to be used, is equal to or greater than a threshold. If the amount of change in the cathode catalyst resistance Rβ is smaller than the threshold, the processing circuit 11 etc. determines that decomposition of the cathode catalyst is unnecessary. On the other hand, if the amount of change in the cathode catalyst resistance Rβ is equal to or greater than the threshold, the processing circuit 11 etc. determines that decomposition of the cathode catalyst is necessary. As described above, in the processes of S136 to S138 etc., it is determined whether the cathode catalyst can be reused as is based on the cathode catalyst resistance Rβ of the electrochemical cell (target electrochemical cell) 5.

[0077] The catalyst determination process ends when the process of S137 or S138 is performed. If no catalyst is present at the cathode of the electrochemical cell 5 (S135-No), the catalyst determination process ends without performing the processes of S136 to S138.

[0078] As described above, at least one of the anode and cathode of the electrochemical cell 5 includes a catalyst. Therefore, when a determination process for the catalyst is performed for a certain electrochemical cell 5, at least one of the process of S132 and the process of S136 is performed. That is, the processing circuit 11 and the like perform at least one of the process of determining whether or not the catalyst of the anode of the electrochemical cell 5 can be reused as is, based on the anode catalyst resistance Rα, and the process of determining whether or not the catalyst of the cathode of the electrochemical cell 5 can be reused as is, based on the cathode catalyst resistance Rβ.

[0079] 6, if it is determined that the electrochemical cell 5 cannot be regenerated without separating the anode and the cathode, the determination process of S127 is not performed. In this example, if it is determined that the electrochemical cell 5 cannot be regenerated without separating the anode and the cathode, the processing circuit 11 etc. determine that it is necessary to decompose the catalyst contained in the electrochemical cell 5. In other words, it is determined that it is necessary to decompose the catalyst regardless of whether it is the catalyst in the anode or the cathode.

[0080] 5 , when it is determined that the plurality of electrochemical cells 5 need to be separated from one another, the processing circuit 11, etc. perform the determination process of S117 for each of all of the electrochemical cells 5. Therefore, when it is determined that the plurality of electrochemical cells 5 need to be separated from one another, the processing circuit 11, etc. determine, for each of the plurality of electrochemical cells 5 constituting the electrochemical module 2, whether or not the electrochemical cell 5 can be reused as is, based on Rc0, which is the sum of the cell membrane resistance Rc1 and the cell catalyst resistance Rc2. Then, when there is an electrochemical cell 5 determined to be unusable as is, the processing circuit 11, etc. determine, for the electrochemical cell 5 determined to be unusable as is, whether or not the electrochemical cell 5 can be regenerated without separating the anode and cathode, based on the cell catalyst resistance Rc2.

[0081] In this embodiment, when it is determined by the process of S115 in the example of FIG. 5 that separation of the plurality of electrochemical cells 5 is not necessary, the electrochemical module 2 is regenerated without separating the plurality of electrochemical cells 5. Regeneration of the electrochemical module 2 without separating the electrochemical cells 5 is also referred to as "refurbishment of the electrochemical module 2." In refurbishment of the electrochemical module 2, the electrochemical module 2 is regenerated without regenerating each of the electrochemical cells 5 individually, as described below.

[0082] In refurbishing the electrochemical module 2, for example, the electrochemical module 2 is washed with an acidic solution while the multiple electrochemical cells 5 are not separated from one another. This removes metal ions and the like adhering to the membranes of each of the electrochemical cells 5 that make up the electrochemical module 2. In one example, the electrochemical module 2 is regenerated by, for example, swapping the positions of the electrochemical cells 5 that make up the electrochemical module 2. However, replacing the electrochemical cells 5 that make up the electrochemical module 2 with electrochemical cells different from those that make up the electrochemical module 2 does not constitute refurbishing the electrochemical module 2 because it requires separating the electrochemical cells 5 to be replaced with new electrochemical cells.

[0083] When it is determined by the process of S125 in the example of FIG. 6 that separation of the anode and cathode in the electrochemical cell 5 is not necessary, the electrochemical cell 5 is regenerated without separating the anode and cathode. Regeneration of the electrochemical cell 5 without separating the anode and cathode is also referred to as "refurbishment of the electrochemical cell 5." In refurbishing the electrochemical cell 5, the electrochemical cell 5 is regenerated without separating the catalyst from the electrode group formed by the anode, cathode, and membrane. In refurbishing the electrochemical cell 5, for example, the electrochemical cell 5 is washed with an acidic solution without separating the catalyst. This removes metal ions and the like adhering to the membrane in the electrochemical cell 5.

[0084] Furthermore, if it is determined that at least one of the catalysts in the anode and cathode needs to be decomposed by the processes in S134 and S138 in the example of FIG. 7, a process for decomposing the corresponding catalyst (either one or both of the catalysts in the anode and cathode) is performed. In this case, the decomposition of the target catalyst is performed using one or both of dry refining and wet refining. By decomposing the target catalyst, elements contained in the catalyst, or compounds or mixtures of elements, are recovered. The recovered elements, compounds or mixtures of elements are then synthesized to regenerate the catalyst. The process of recovering elements, etc. by decomposing the catalyst and regenerating the catalyst by synthesizing the recovered elements, etc. is also simply referred to as "recycling."

[0085] As described above, in this embodiment, it is determined whether the electrochemical cell 5 to be treated can be reused as is based on the sum Rc0 of the cell membrane resistance Rc1 and the cell catalyst resistance Rc2. Then, it is determined whether the electrochemical cell 5 can be regenerated without separating the anode and cathode based on the cell catalyst resistance Rc2. Therefore, in cases where the electrochemical cell 5 can be regenerated by a regeneration process without separating the catalyst from the electrode group, the electrochemical cell 5 can be regenerated and reused without separating the anode and cathode. This allows the electrochemical cell 5 to be effectively reused in accordance with the state of the electrochemical cell 5, and the electrochemical cell 5 can be reused in a state with high added value.

[0086] Furthermore, in an electrochemical cell 5 in which both the anode and the cathode are provided with catalysts, even when the cell catalyst resistance Rc2 of the electrochemical cell 5 is high, the degree of catalyst degradation may be high in one of the anode and the cathode, and low in the other of the anode and the cathode. In one example of this embodiment, when it is determined that the electrochemical cell 5 cannot be regenerated without separating the anode and the cathode, at least one of the following determinations is made: whether the anode catalyst needs to be decomposed based on the anode catalyst resistance Rα; or whether the cathode catalyst needs to be decomposed based on the cathode catalyst resistance Rβ. Therefore, in cases where the degree of catalyst degradation is high only in one of the anode and the cathode, the anode catalyst or the cathode catalyst with the low degree of degradation can be reused without decomposition. This allows the catalyst of the electrochemical cell 5 to be effectively reused in accordance with the state of the electrochemical cell 5, thereby enabling the catalyst to be reused in a state with high added value.

[0087] Furthermore, in this embodiment, for an electrochemical module 2 configured from a plurality of electrochemical cells 5, it is determined based on the module catalyst resistance Rm2 whether the electrochemical module 2 can be regenerated without separating the plurality of electrochemical cells 5 from one another. Therefore, in cases where the electrochemical module 2 can be regenerated by a regeneration process without separating the electrochemical cells 5 from one another, the electrochemical module 2 becomes regenerative and reusable without performing a regeneration process on each electrochemical cell 5 individually. This makes it possible to effectively reuse the electrochemical module 2 in accordance with the state of the electrochemical cells 5 that configure the electrochemical module 2, and to reuse the electrochemical module 2 in a state with high added value.

[0088] Furthermore, in this embodiment, for each electrochemical cell 5, parameters used in the above-described determination, such as the cell membrane resistance Rc1 and the cell catalyst resistance Rc2, are estimated based on the measurement results of the impedance frequency characteristics of the electrochemical cell 5. Therefore, for each electrochemical cell 5, a determination regarding reuse, recycling, etc. is made based on parameters appropriately estimated in correspondence with the internal state. Furthermore, for the electrochemical module 2, parameters used in the above-described determination, such as the module catalyst resistance Rm2, are estimated based on the measurement results of the impedance frequency characteristics of the electrochemical module 2. Therefore, for the electrochemical module 2, a determination regarding reuse, recycling, etc. is made based on parameters appropriately estimated in correspondence with the internal state.

[0089] Furthermore, in this embodiment, in each of the diagnoses that are periodically performed while the electrochemical module 2 is in use, the impedance frequency characteristics are measured for each of the electrochemical module 2 and the electrochemical cell 5, and the above-mentioned parameters used to determine the cell catalyst resistance Rc2, the module catalyst resistance Rm2, etc. are estimated. Therefore, in the determination process, it is possible to make a determination using the parameters estimated in the diagnosis, reducing the effort required to newly obtain parameters to be used in the determination.

[0090] Furthermore, in the determination process, instead of using the value of a parameter such as cell catalyst resistance Rc2, the determination is made based on the amount of change (increase) in the parameter from a predetermined point in time, such as when the electrochemical module 2 began to be used, thereby improving the accuracy of the determination. This allows for a more appropriate determination regarding reuse, recycling, etc. of the electrochemical cell 5. Furthermore, in the determination process, the determination is made using the results of parameter estimation from multiple diagnoses performed over different periods of time, rather than the results of parameter estimation from a single diagnosis, thereby improving the accuracy of the determination. This allows for a more appropriate determination regarding reuse, recycling, etc. of the electrochemical cell 5.

[0091] In the processing system 1, a temperature adjustment device that adjusts the environmental temperature of the environment in which the electrochemical module 2 is placed may be provided around the electrochemical module 2 so that the environmental temperature falls within the specified temperature range. In addition, any of an air cooling device or liquid cooling device that can lower the environmental temperature of the electrochemical module 2, or a heater that can raise the environmental temperature may be provided around the electrochemical module 2.

[0092] In at least one of the above-described embodiments or examples, a determination is made as to whether a target electrochemical cell can be reused as is based on the sum of the cell membrane resistance due to the membrane and the cell catalyst resistance due to the catalyst. If it is determined that the target electrochemical cell cannot be reused as is, a determination is made as to whether the target electrochemical cell can be regenerated without separating the anode and cathode based on the cell catalyst resistance. It is possible to provide a processing method, processing device, and processing program related to an electrochemical cell that enables the electrochemical cell to be effectively reused in accordance with the state of the electrochemical cell in determining whether the electrochemical cell can be reused or recycled.

[0093] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied 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 modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims.

Claims

1. A processing method relating to an electrochemical cell in which at least one of an anode and a cathode is provided with a catalyst, and an electrochemical reaction occurs in response to an input of electric power, or an electric power generated by the electrochemical reaction is output, comprising: determining whether or not a target electrochemical cell can be reused as is based on the sum of a cell membrane resistance due to a membrane and a cell catalyst resistance due to a catalyst for the target electrochemical cell; When it is determined that the target electrochemical cell cannot be reused as it is, determining whether or not the target electrochemical cell can be restored without separating the anode and the cathode based on the cell catalyst resistance; A processing method comprising:

2. When it is determined that the target electrochemical cell cannot be regenerated without separating the anode and the cathode, Determine whether the catalyst of the anode of the target electrochemical cell can be reused as is based on an anode catalyst resistance caused by the catalyst of the anode; and Determine whether the catalyst of the cathode of the target electrochemical cell can be reused as is based on the cathode catalyst resistance caused by the catalyst of the cathode; The method of claim 1 , further comprising performing at least one of:

3. 3. The treatment method of claim 2, further comprising recovering elements contained in the catalyst, or compounds or mixtures of the elements, by decomposing the catalyst determined to be unable to be reused as is in the target electrochemical cell.

4. For a target electrochemical module in which a plurality of the electrochemical cells are electrically connected, determining whether the target electrochemical module can be regenerated without isolating the plurality of the electrochemical cells from each other based on a module catalyst resistance caused by a catalyst; When it is determined that the target electrochemical module cannot be regenerated without separating the plurality of electrochemical cells from each other, determining whether each of the plurality of electrochemical cells constituting the target electrochemical module can be reused as is based on the sum of the cell membrane resistance and the cell catalyst resistance; When there is an electrochemical cell determined to be unable to be reused as it is, determining whether or not the electrochemical cell determined to be unable to be reused as it is can be regenerated without separating the anode and the cathode based on the cell catalyst resistance; The method of any one of claims 1 to 3, further comprising:

5. and diagnosing the target electrochemical module and each of the plurality of electrochemical cells constituting the target electrochemical module by estimating the module catalyst resistance of the target electrochemical module and the cell membrane resistance and the cell catalyst resistance of each of the plurality of electrochemical cells constituting the target electrochemical module during use of the target electrochemical module; The determination of the target electrochemical module is made using the estimated result of the module catalyst resistance obtained in the diagnosis during use; the determination for each of the plurality of electrochemical cells constituting the target electrochemical module is performed using the estimated results of the cell membrane resistance and the cell catalyst resistance obtained in the diagnosis during use. The processing method according to claim 4.

6. diagnosing the target electrochemical cell by estimating the cell membrane resistance and the cell catalyst resistance of the target electrochemical cell during use of the target electrochemical cell; The determination of the target electrochemical cell is made using the estimated results of the cell membrane resistance and the cell catalyst resistance obtained in a diagnosis during use. The processing method according to any one of claims 1 to 3.

7. 4. The treatment method according to claim 1, further comprising: regenerating the target electrochemical cell determined to be regenerable without separating the anode and the cathode, without separating the anode and the cathode.

8. In the determination of the target electrochemical cell, any one of a water electrolysis cell that electrolyzes water by the input of electric power, a P2C cell that electrolyzes carbon dioxide by the input of electric power, and a fuel cell that generates the electric power by supplying oxygen and fuel is determined as the target electrochemical cell. The processing method according to any one of claims 1 to 3.

9. A processing device associated with an electrochemical cell in which at least one of an anode and a cathode is provided with a catalyst, and in which an electrochemical reaction occurs in response to an input of electric power, or which outputs electric power generated by the electrochemical reaction, determining whether or not the target electrochemical cell can be reused as is based on the sum of the cell membrane resistance due to the membrane and the cell catalyst resistance due to the catalyst; when it is determined that the target electrochemical cell cannot be reused as it is, determining whether or not the target electrochemical cell can be restored without separating the anode and the cathode based on the cell catalyst resistance; A processing device comprising a processor.

10. A processing program related to an electrochemical cell in which at least one of an anode and a cathode is provided with a catalyst, and an electrochemical reaction occurs in response to an input of electric power, or the electrochemical cell outputs electric power generated by the electrochemical reaction, the processing program being configured to execute the following on a computer: determining whether or not a target electrochemical cell can be reused as is based on the sum of a cell membrane resistance due to the membrane and a cell catalyst resistance due to the catalyst; when it is determined that the target electrochemical cell cannot be reused as it is, determining whether or not the target electrochemical cell can be restored without separating the anode and the cathode based on the cell catalyst resistance; Processing program.

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