Impedance measurement device and impedance measurement method

Abstract

When a non-measurement object and a measurement object formed by connecting a plurality of impedance elements in series are connected in parallel, the impedance of the measurement object impedance element is measured. The present invention is provided with: a measurement current output unit (3) for supplying an alternating current (Im) for measurement using a portion of electrochemical cells (C1-C5) as measurement target cells in a state in which a power supply device (PD) is connected in parallel to a measurement target (DUT); a current sensor (5-1) that measures the supply current value of the alternating current (Im) for measurement; and a processing unit (6) that calculates the impedance of the cell to be measured on the basis of the supply current value and the voltage value of the voltage across both ends of the cell to be measured, and the measurement current output unit (3) outputs the impedance of the cell to be measured via a measurement current supply line (Li) connected to the measurement current supply points (Ps1, Ps3) so as to include the cell to be measured between the measurement current supply points (Ps1, Ps3) and the measurement current supply points (Ps1, Ps3). A current sensor (5-1) is disposed between the electrochemical cell (C1) and the connection point (Pc1) and the measurement current supply point (Ps1), and supplies an alternating current (Im) for measurement to the cell to be measured, and the current sensor (5-1) is disposed between the connection point (Pc1) and the measurement current supply point (Ps1).

Description

Technical Field

[0001] The present invention relates to an impedance measuring device and an impedance measuring method capable of measuring the impedance of some or all of the multiple impedance elements when a non-object to be measured is connected in parallel to an object to be measured, which is composed of multiple impedance elements connected in series, via a connecting line. Background Technology

[0002] An impedance measuring device that can measure the impedance of a target object when a non-target object is connected in parallel with the target object via a connecting line is known, as disclosed in the following patent document. This impedance measuring device is configured to measure the internal impedance of a secondary battery when a load (not the target object) is connected in parallel with the target secondary battery via a power supply line (the connecting line). Specifically, this impedance measuring device includes an AC current supply unit, an AC voltage detection unit, an AC current detection unit, an A / D conversion (analog-to-digital conversion) unit, and an arithmetic control unit. In this case, the AC current detection unit is configured to include a clamp-type current sensor.

[0003] When using this impedance measuring device to measure the internal impedance of a secondary battery, firstly, the power cord is plugged into the opening of the clamp-on current sensor in the AC current detection unit. In this state, the AC current supply unit supplies the measuring AC current to the power cord. As a result, a portion of the measuring AC current flows through the secondary battery. Furthermore, the remaining portion of the measuring AC current flows through the load, and a DC current output from the secondary battery also flows. In this case, the current sensor in the AC current detection unit detects the AC current flowing in the power cord plugged into the opening and outputs a negative feedback current corresponding to the AC current value. At this time, an AC voltage is generated across the detection resistor by the flow of the feedback current. Next, the A / D conversion unit performs A / D conversion on the AC current data representing the AC current value and outputs it to the arithmetic control unit. Furthermore, the AC voltage detection unit detects the voltage generated across the secondary battery and outputs AC voltage data representing the voltage value to the arithmetic control unit. Next, the arithmetic control unit calculates the internal impedance of the secondary battery based on the AC current value represented by the input AC current data and the voltage value of the two terminals represented by the input AC voltage data.

[0004] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2004-251625 (pp. 3-8, Figure 1) Summary of the Invention The problem that the invention aims to solve However, the impedance measuring device described above has the following problems. Specifically, as explained below... Figure 5 As conceptually illustrated, this presents a problem when, for example, an electrolysis apparatus that generates hydrogen and oxygen is used as the test object (DUT), and the impedance measuring device 1X described above is used to measure the impedance of the test object DUT in operation. In this case, the test object DUT is connected in parallel with a power supply device PD that supplies DC current to the test object DUT via a power supply line Lp, which serves as a connection line. Therefore, when measuring the impedance of the test object DUT in operation, the AC current supply unit U1 supplies a measuring AC current Im to the test object DUT via the measuring current supply line Li and terminals T1 and T11 at both ends of the test object DUT. In this state, the current sensor U4 measures the current value of the measuring AC current Im flowing in the test object DUT, and the AC voltage detection unit U2 measures the voltage value of the AC voltage generated between terminals T1 and T11 of the test object DUT. Next, the arithmetic control unit U3 measures the impedance of the DUT (Device Under Test) based on the current value of the measuring AC current Im detected by the current sensor U4 and the voltage value of the AC voltage detected by the AC voltage detection unit U2.

[0005] In this case, the impedance of the power supply device PD in operation is extremely small compared to the impedance of the object being measured, DUT. Therefore, in Figure 5 In the measurement state shown, the terminals T1 and T11 of the DUT being measured are essentially short-circuited due to the power supply line Lp. Therefore, even if the AC current supply unit UI outputs a measurement AC current Im, almost all of the measurement AC current Im is shunted to the power supply device PD, resulting in the measurement AC current Im not flowing through the DUT. Consequently, the AC voltage between terminals T1 and T11 of the DUT is approximately zero volts. As a result, the AC voltage detection unit U2 cannot detect the AC voltage generated across the DUT. Therefore, in this impedance measurement device 1X, the following problem exists: the impedance of the DUT cannot be measured when a low-impedance non-measuring object is connected in parallel with the DUT.

[0006] The present invention was made in view of the above-mentioned problems, and its main objective is to provide an impedance measuring device and an impedance measuring method that can measure the impedance of some or all of the multiple impedance elements when the non-measured object is connected in parallel to the measured object, which is composed of multiple impedance elements connected in series, via a connecting line.

[0007] Solution for solving the problem To achieve the above objectives, the impedance measuring apparatus of the present invention comprises: a measuring current supply unit, which, for a measuring object configured to have a plurality of impedance elements connected in series between a pair of terminals, and in a state where a non-measuring object is connected in parallel to the measuring object via a connecting line, supplies a portion of the plurality of impedance elements as measuring object impedance elements via a measuring current supply line to the measuring object impedance elements, wherein the connecting line is connected to a pair of connection points respectively defined on the pair of terminals, and the measuring current supply line is respectively connected to one measuring current supply point and another measuring current supply point defined on any one of the pair of terminals; a first current sensor, which measures the supply current value of the measuring AC current supplied to the measuring object impedance element; and a voltage measuring unit, which measures the voltage value across the two ends of the measuring object impedance element. The impedance measuring device comprises a measuring current supply unit and a processing unit, which calculate the impedance of the impedance element to be measured based on the measured supply current value and the voltage value of the voltage across the two terminals. In the impedance measuring device, the measuring current supply unit supplies the measuring alternating current to the impedance element to be measured via a pair of measuring current supply lines that are respectively connected to the one measuring current supply point and the other measuring current supply point in a manner that includes the impedance element to be measured in the current path between the one measuring current supply point and the other measuring current supply point. The other measuring current supply point is connected to the connection point of any two impedance elements that are connected in series among the plurality of impedance elements. The first current sensor is disposed between the connection point specified on the terminal side of the pair of connection points and the impedance element connected to the terminal of the one measuring current supply point.

[0008] Furthermore, to achieve the above objectives, the impedance measurement method of the present invention is for a measurement object configured to have multiple impedance elements connected in series between a pair of terminals. With a non-measurement object connected in parallel to the measurement object via a connecting line, a portion of the multiple impedance elements is used as the measurement object impedance element. A measurement alternating current is supplied to the measurement object impedance element via a measurement current supply line. The connecting line is connected to a pair of connection points defined on the pair of terminals, and the measurement current supply line is connected to one measurement current supply point and another measurement current supply point defined on either of the pair of terminals. A first current sensor is used to measure the supply current value of the measurement alternating current supplied to the measurement object impedance element, and the voltage value across the two ends of the measurement object impedance element is measured. Based on the measured supply current... The impedance of the impedance element to be measured is determined by the voltage value of the voltage across the two ends. In the impedance measurement method, the measuring alternating current is supplied to the impedance element to be measured via a pair of measuring current supply lines that are respectively connected to one measuring current supply point and the other measuring current supply point in a manner that includes the impedance element to be measured in the current path between the one measuring current supply point and the other measuring current supply point. The other measuring current supply point is connected to the connection point of any two of the plurality of impedance elements that are connected in series. The first current sensor is arranged between the connection point specified on the terminal side of the pair of connection points and the impedance element connected to the terminal of the one measuring current supply point, and the supply current value of the measuring alternating current supplied to the impedance element to be measured is measured.

[0009] In this impedance measuring device and impedance measuring method, an alternating current for measuring is supplied to the impedance element to be measured via a pair of measuring current supply lines, which are respectively connected to one measuring current supply point and another measuring current supply point in a manner that includes the impedance element to be measured within a current path between one measuring current supply point and another measuring current supply point. The other measuring current supply point is connected to the connection point of any two of the impedance elements that are connected in series among a plurality of impedance elements. A first current sensor is disposed between a connection point on the terminal side of one of the pair of connection points and a measuring current supply point and an impedance element connected to the terminal.

[0010] Therefore, according to this impedance measuring device and impedance measuring method, even when a non-measuring object with low impedance is connected in parallel with a measuring object configured to have multiple impedance elements, by using a portion of the multiple impedance elements as the measuring object impedance element, a measuring alternating current can be supplied to the measuring object impedance element. As a result, the supply current value of the measuring alternating current flowing only in the measuring object impedance element and the voltage value of the voltage across the measuring object impedance element when the measuring alternating current is supplied to the measuring object impedance element can be measured, thus reliably measuring the impedance of the measuring object impedance element.

[0011] Furthermore, in this impedance measuring device and method, a portion of the multiple impedance elements is used as the target impedance element. A measuring alternating current is supplied to the target impedance element via a measuring current supply line connected to one measuring current supply point and another measuring current supply point defined on either side of a pair of terminals. Therefore, the current path through the connecting line includes one or more target impedance elements with sufficiently high impedance. Thus, even if the non-target has low impedance, the overall impedance of the current path becomes high. Therefore, according to this impedance measuring device and method, the value of the measuring alternating current shunted to the non-target can be reduced, and the supply current value of the measuring alternating current shunted to the target impedance element can be correspondingly increased. As a result, the voltage value generated across the target impedance element can be increased. Therefore, according to this impedance measuring device and method, the ratio (S / N) of the signal level (S) to the noise level (N) of the measured voltage across the target can be sufficiently improved, thus enabling the measurement of the impedance of the target impedance element with sufficiently high accuracy.

[0012] Furthermore, the impedance measuring device of the present invention uses either an electrolytic device or an electrolytic reduction device having multiple impedance elements as the object of measurement, and uses a portion of the multiple impedance elements as the object of measurement impedance elements to measure the impedance.

[0013] Furthermore, the impedance measurement method of the present invention takes either an electrolytic device or an electrolytic reduction device having multiple impedance elements as the measurement object, and uses a portion of the multiple impedance elements as the measurement object impedance elements to measure the impedance.

[0014] In this impedance measuring device and impedance measuring method, a power supply device with multiple impedance elements is taken as the non-measured object, and either an electrolysis device or an electrolytic reduction device is taken as the measured object. A portion of the multiple impedance elements is taken as the measured object impedance elements to measure the impedance. Thus, when a power supply device with extremely low output impedance is connected in parallel with the measured object, the impedance of the measured object impedance elements can be reliably measured.

[0015] Furthermore, the impedance measuring device of the present invention includes: a first switch for switching between a first switching state and a second switching state, wherein the first switching state is a state in which any one terminal is used as one of the terminals in the pair of terminals, and the second switching state is a state in which any one terminal is used as the other terminal in the pair of terminals; and a second switch for switching the impedance element to be measured connected to the voltage measuring unit, wherein the processing unit controls the switching of the first switch and the second switch.

[0016] According to the impedance measuring device, the processing unit controls the switching of the first switch and the second switch, thereby automatically switching the connection between the voltage measuring unit and the impedance elements of the two groups of objects to be measured, without having to manually connect the voltage measuring unit to the impedance elements of the objects to be measured.

[0017] Furthermore, in the impedance measuring device of the present invention, the processing unit calculates the impedance of the target impedance element by treating a portion of the impedance elements as the target impedance element in the first switching state, and calculates the impedance of the target impedance element by treating all the other impedance elements except the portion of impedance elements as the target impedance element in the second switching state. The sum of the impedances of all the target impedance elements calculated in the first switching state and the impedances of all the target impedance elements calculated in the second switching state is used as the impedance of the target.

[0018] According to the impedance measuring device, the processing unit calculates the impedance of the measuring object impedance element calculated in the first switching state and the impedance of the measuring object impedance element calculated in the second switching state as the impedance of the measuring object. Thus, the impedance of the measuring object (that is, all the measuring object impedance elements) can be calculated by performing only two impedance measurements.

[0019] Furthermore, in the impedance measuring device of the present invention, the first current sensor is disposed on the one terminal side, and the impedance measuring device includes: a second current sensor disposed on the other terminal side, for measuring the supply current value of the measuring AC current supplied to the impedance element to be measured; and a third switch for switching the supply current value measured by the first current sensor and the supply current value measured by the second current sensor and outputting them to the processing unit. The second current sensor is disposed between a connection point on the other terminal side of one of the pair of connection points and the one measuring current supply point in the second switching state and the impedance element connected to the other terminal. The processing unit controls the switching of the third switch, thereby inputting the supply current value measured by the first current sensor in the first switching state and inputting the supply current value measured by the second current sensor in the second switching state.

[0020] In this impedance measuring device, the processing unit controls the switching of the third switch, thereby inputting the supply current value measured by the first current sensor when the first switch is switched to the first switching state, and inputting the supply current value measured by the second current sensor when the first switch is switched to the second switching state.

[0021] Therefore, according to this impedance measuring device, two current sensors are used, so there is no need to remove the first current sensor to use as the second current sensor. The processing unit switches the third switch, so that the supply current value measured by the first current sensor and the supply current value measured by the second current sensor can be input automatically in a short time.

[0022] Furthermore, in the impedance measuring device of the present invention, the first current sensor and the second current sensor are configured as non-contact current sensors that can be opened and closed.

[0023] According to the impedance measuring device, the first current sensor and the second current sensor are composed of non-contact current sensors configured as clamps that can be opened and closed, so the first current sensor and the second current sensor can be assembled at any position in the object being measured.

[0024] Furthermore, the impedance measurement method of the present invention uses a non-contact current sensor configured as an openable and closable clamp as the first current sensor.

[0025] According to this impedance measurement method, a non-contact current sensor configured as an openable and closable clamp is used, thereby allowing the first current sensor to be mounted at any position in the object being measured.

[0026] Furthermore, in the impedance measuring apparatus of the present invention, the measuring current supply unit is configured to change the frequency of the measuring AC current according to a frequency control signal, and the processing unit outputs the frequency control signal to the measuring current supply unit to change the frequency of the measuring AC current, thereby obtaining the frequency characteristics of the impedance of the measured impedance element at the plurality of frequencies.

[0027] Furthermore, the impedance measurement method of the present invention obtains the frequency characteristics of the impedance of the measured impedance element at multiple frequencies.

[0028] Based on the impedance measuring device and impedance measuring method, the frequency characteristics of the impedance of the measured impedance element at multiple frequencies can be obtained, thereby enabling the determination of the performance and degradation of the measured impedance element.

[0029] Furthermore, in the impedance measuring apparatus of the present invention, the processing unit obtains the frequency characteristics of the impedance of the measured object based on the frequency characteristics of the impedance of the measured object's impedance element.

[0030] Furthermore, the impedance measurement method of the present invention obtains the frequency characteristics of the impedance of the object being measured based on the frequency characteristics of the impedance of the impedance element of the object being measured.

[0031] Based on the impedance measuring device and impedance measuring method, the frequency characteristics of the impedance of the object under test at multiple frequencies can be obtained, thereby enabling the determination of the performance and degradation of the object under test.

[0032] Furthermore, in the impedance measuring device of the present invention, the processing unit acquires either the Cole-Cole diagram or the Bode plots as the frequency characteristic.

[0033] Furthermore, the impedance measurement method of the present invention obtains either the Cole-Cole plot or the Bode plot as the frequency characteristic.

[0034] Based on the impedance measuring device and impedance measuring method, either the Cole-Cole plot or the Bode plot can be obtained as the frequency characteristic, thereby enabling high-precision identification of the performance and degradation related to the impedance element and the measured object.

[0035] Invention Effects According to the impedance measuring apparatus and impedance measuring method of the present invention, even when a non-measuring object with low impedance is connected in parallel with a measuring object configured to have multiple impedance elements, by using a portion of the multiple impedance elements as the measuring object impedance element, a measuring alternating current can be supplied to the measuring object impedance element, and the supply current value of the measuring alternating current flowing only in the measuring object impedance element can be measured, thus reliably measuring the impedance of the measuring object impedance element. Attached Figure Description

[0036] Figure 1 This is a configuration diagram showing the structure of impedance measuring device 1.

[0037] Figure 2 This is a configuration diagram showing the structure of the scanning unit 2.

[0038] Figure 3 This is a configuration diagram showing the connection relationships of the constituent elements of the impedance measuring device 1 when no control signal Sc is output.

[0039] Figure 4 This is a diagram showing the connection relationships of the components of the impedance measuring device 1 when the output control signal Sc is received.

[0040] Figure 5 This is an explanatory diagram illustrating the use of the conventional impedance measuring device 1X. Detailed Implementation

[0041] Hereinafter, with reference to the accompanying drawings, embodiments of the impedance measuring device and the impedance measuring method using the impedance measuring device will be described.

[0042] Figure 1 The impedance measuring device 1 shown is an example of an impedance device that performs an impedance measuring method. It is configured such that when a non-measured object is connected in parallel to a measured object consisting of multiple impedance elements connected in series via a power supply line Lp, it can measure the impedance of the measured object impedance element by treating some or all of the multiple impedance elements as the measured object impedance element.

[0043] In this case, the following can be considered as the object of measurement: an electrolysis apparatus that consists of multiple electrochemical units (an example of impedance elements) connected in series and stacked; an electrolytic reduction apparatus that consists of multiple electrolyte membranes (an example of impedance elements) connected in series and stacked; an apparatus using ion exchange membranes (an example of impedance elements) connected in series and stacked; a fuel cell that consists of multiple power generation units (an example of impedance elements) connected in series and stacked; and lithium-ion batteries, lead-acid batteries, etc., that consist of multiple battery units (an example of impedance elements) connected in series and stacked. Furthermore, as non-objects of measurement, power supply devices such as inverters and converters, various loads such as electronic devices, and various power generation devices such as fuel cells in operation or not in operation can be considered. Hereinafter, as an example, an example will be given where the electrolysis apparatus is the object of measurement (DUT), and the power supply device (PD) supplying driving power to the object of measurement (DUT) is a non-object of measurement.

[0044] First, the object of measurement should be described. For example... Figure 1 As shown, in this example, an electrolysis device configured as a stack of multiple electrochemical units C1 to C10 (hereinafter, without distinction, also referred to as "electrochemical unit C") connected in series is used as the DUT to be measured. It should be noted that the electrolysis device is actually constructed by connecting dozens to hundreds of electrochemical units C in series, but in this example, for ease of understanding, a device configured by connecting ten electrochemical units C1 to C10 in series is used as the DUT to be measured. In this case, the DUT to be measured has a pair of input terminals T1 and T11 (an example of a pair of terminals) and terminals T2 to T10 (hereinafter, without distinction, also referred to as "terminal T") connected to the connection points of each electrochemical unit C1 to C10.

[0045] Next, the configuration of impedance measuring device 1 will be described. For example... Figure 1 As shown, the impedance measuring device 1 is configured to include a scanning unit 2, a current measuring output unit 3, voltage measuring units 4-1 to 4-5 (hereinafter, without distinction, also referred to as "voltage measuring unit 4"), current sensors 5-1 and 5-2 (hereinafter, without distinction, also referred to as "current sensor 5"), a processing unit 6, an output unit 7, voltage detection probes P1 to P20 (hereinafter, without distinction, also referred to as "probe P"), and current supply probes Pi1 to Pi3.

[0046] like Figure 2As shown, the scanning unit 2 is configured to include switches S1, S2, S11 to S20 (hereinafter, without distinguishing between the switches, they are also referred to as "switches S"), and terminals T21 to 25 and terminals T31 to T64. In this case, when no control signal Sc is output from the processing unit 6 (when no control signal Sc is output), each switch S maintains a first switching state in which the fixed contact c is connected to the movable contact a (the state in which any one terminal is set as terminal T1 of a pair of terminals T1 and T11). When the processing unit 6 outputs the control signal Sc (when the control signal Sc is output), each switch S maintains a second switching state in which the fixed contact c is connected to the movable contact b (the state in which any one terminal is set as the other terminal T11 of a pair of terminals T1 and T11).

[0047] Furthermore, switch S1 functions as a first switch, switching the supply destination of the AC measuring current Im output from the measuring current output unit 3 according to the control signal Sc output from the processing unit 6 via terminal 64. Specifically, when no control signal Sc is output, switch S1 connects terminal T61, which is connected to one output unit of the measuring current output unit 3 and to the fixed contact c, to terminal T21, which is connected to probe Pi1 and to the movable contact a. When the control signal Sc is output, switch S1 connects terminal T61 to terminal T22, which is connected to probe Pi2 and to the movable contact b. It should be noted that terminal 23 and terminal 62 are connected inside the scanning unit 2, thereby connecting probe Pi3, which will be described later, connected to terminal 23, to another output unit of the measuring current output unit 3 connected to terminal 62.

[0048] Furthermore, switch S2 functions as a third switch, switching and outputting the current value data Di (supply current value) measured by current sensor 5-1 (which is described later as the first current sensor) and current value data Di (supply current value) measured by current sensor 5-2 (which is described later as the second current sensor) to the processing unit 6 according to the control signal Sc output from the processing unit 6. Specifically, when no control signal Sc is output, switch S2 connects terminal T63, which is connected to the processing unit 6 and to the fixed contact c, to terminal T24, which is connected to current sensor 5-1 and to the movable contact a. When the control signal Sc is output, switch S2 connects terminal T63 to terminal T25, which is connected to current sensor 5-2 and to the movable contact b.

[0049] Furthermore, switches S11 to S20 function as second switches, switching the electrochemical unit C, which is the unit to be measured, connected to the voltage measuring unit 4 according to the control signal Sc output from the processing unit 6. Specifically, switches S11 and S12 have the function of connecting either electrochemical unit C1 or electrochemical unit C10 to the voltage measuring unit 4-1. In this case, when the control signal Sc is not output, switch S11 connects terminal T51, which is connected to an input part of the voltage measuring unit 4-1 and to the fixed contact c of switch S11, to terminal T31, which is connected to terminal T1, the unit to be measured, and to the movable contact a. When the control signal Sc is output, switch S11 connects terminal T51 to terminal T50, which is connected to terminal T11, the unit to be measured, and to the movable contact b. Furthermore, when no control signal Sc is output, switch S12 connects terminal T52, which is connected to another input unit of voltage measuring unit 4-1 and to fixed contact c of switch S12, to terminal T2, which is connected to the measuring object DUT and to movable contact a. When the control signal Sc is output, switch S12 connects terminal T52 to terminal T49, which is connected to terminal T10, which is connected to the measuring object DUT and to movable contact b.

[0050] Furthermore, switches S13 and S14 have the function of connecting either electrochemical unit C2 or electrochemical unit C9 to voltage measuring unit 4-2. In this case, when no control signal Sc is output, switch S13 connects terminal T53, which is connected to an input section of voltage measuring unit 4-2 and to fixed contact c of switch S13, to terminal T2, which is connected to the test object DUT, and to terminal T33, which is connected to movable contact a. When the control signal Sc is output, switch S13 connects terminal T53 to terminal T10, which is connected to the test object DUT, and to terminal T48, which is connected to movable contact b. Furthermore, when no control signal Sc is output, switch S14 connects terminal T54, which is connected to another input part of voltage measuring unit 4-2 and to fixed contact c of switch S14, to terminal T34, which is connected to terminal T3 of the measured object DUT and to movable contact a. When the control signal Sc is output, switch S14 connects terminal T54 to terminal T9 of the measured object DUT and to terminal T47, which is connected to movable contact b.

[0051] Furthermore, switches S15 and S16 have the function of connecting either electrochemical unit C3 or electrochemical unit C8 to voltage measuring unit 4-3. In this case, when no control signal Sc is output, switch S15 connects terminal T55, which is connected to an input section of voltage measuring unit 4-3 and to fixed contact c of switch S15, to terminal T35, which is connected to terminal T3 of the test object DUT and to movable contact a. When the control signal Sc is output, switch S15 connects terminal T55 to terminal T9 of the test object DUT and to terminal T46, which is connected to movable contact b. Furthermore, when no control signal Sc is output, switch S16 connects terminal T56, which is connected to another input part of voltage measuring unit 4-3 and to fixed contact c of switch S16, to terminal T4, which is connected to the measured object DUT, and to terminal T36, which is connected to movable contact a. When the control signal Sc is output, switch S16 connects terminal T56 to terminal T8, which is connected to the measured object DUT, and to terminal T45, which is connected to movable contact b.

[0052] Furthermore, switches S17 and S18 have the function of connecting either electrochemical unit C4 or electrochemical unit C7 to voltage measuring unit 4-4. In this case, when no control signal Sc is output, switch S17 connects terminal T57, which is connected to an input section of voltage measuring unit 4-4 and to fixed contact c of switch S17, to terminal T4, which is connected to the test object DUT, and to terminal T37, which is connected to movable contact a. When the control signal Sc is output, switch S17 connects terminal T57 to terminal T8, which is connected to the test object DUT, and to terminal T44, which is connected to movable contact b. Furthermore, when no control signal Sc is output, switch S18 connects terminal T58, which is connected to another input part of voltage measuring unit 4-4 and to fixed contact c of switch S18, to terminal T5, which is connected to the measuring object DUT, and to terminal T38, which is connected to movable contact a. When the control signal Sc is output, switch S18 connects terminal T58 to terminal T7, which is connected to the measuring object DUT, and to terminal T43, which is connected to movable contact b.

[0053] Furthermore, switches S19 and S20 have the function of connecting either electrochemical unit C5 or electrochemical unit C6 to voltage measuring unit 4-5. In this case, when no control signal Sc is output, switch S19 connects terminal T59, which is connected to an input section of voltage measuring unit 4-5 and to fixed contact c of switch S19, to terminal T5, which is connected to the test object DUT, and to terminal T39, which is connected to movable contact a. When the control signal Sc is output, switch S19 connects terminal T59 to terminal T7, which is connected to the test object DUT, and to terminal T42, which is connected to movable contact b. Furthermore, when no control signal Sc is output, switch S20 connects terminal T60, which is connected to another input part of voltage measuring unit 4-5 and to fixed contact c of switch S20, to terminal T40, which is connected to terminal T6 of the measured object DUT and to movable contact a. When the control signal Sc is output, switch S20 connects terminal T60 to terminal T41, which is connected to terminal T6 of the measured object DUT and to movable contact b.

[0054] The measuring current output unit 3 functions as a measuring current supply unit, supplying measuring AC current to the measurement target unit. Following the instructions of the processing unit 6, it generates and outputs a sinusoidal AC signal, i.e., a measuring AC current Im, for measuring the impedance of the measurement target unit. Furthermore, measuring current supply lines Li are connected to one output unit and the other output unit of the measuring current output unit 3. Therefore, as... Figure 3 As shown, when no control signal Sc is output, the measuring current output unit 3 outputs a measuring AC current Im to the electrochemical units C1 to C5, which are the units to be measured, via the measuring current supply line Li, the measuring current supply line Li, and probes Pi1 and Pi3. Furthermore, as... Figure 4 As shown, when the output control signal Sc is output, the measuring current output unit 3 outputs a measuring AC current Im to the electrochemical units C10 to C6, which are the units to be measured, via the measuring current supply line Li, the measuring current supply line Li, and probes Pi2 and Pi3. Furthermore, the measuring current output unit 3 is configured to change the frequency of the measuring AC current Im, and outputs the current after scanning (changing) the frequency of the measuring AC current Im according to the frequency control signal Sf output from the processing unit 6.

[0055] like Figure 3 As shown, the voltage measuring unit 4-1, following the instructions of the processing unit 6, measures the voltage (V1 across the electrochemical unit C1, the unit being measured) generated between probes P1 and P2 when no control signal Sc is output, and outputs the voltage value data Dv1, representing the measured value (the voltage value across the two ends), to the processing unit 6. Furthermore, as... Figure 4As shown, the voltage measuring unit 4-1, following the instructions of the processing unit 6, measures the voltage (V1 across the two ends of the electrochemical unit C10, which is the unit to be measured) generated between the probes P20 and P19 when outputting the control signal Sc, and outputs the voltage value data Dv1 representing the measured value to the processing unit 6.

[0056] like Figure 3 As shown, the voltage measuring unit 4-2, following the instructions of the processing unit 6, measures the voltage (V2 across the electrochemical unit C2, the unit being measured) generated between probes P3 and P4 when no control signal Sc is output, and outputs the voltage value data Dv2, representing the measured value (the voltage value across the two ends), to the processing unit 6. Furthermore, as... Figure 4 As shown, the voltage measuring unit 4-2, following the instructions of the processing unit 6, measures the voltage (V2 across the two ends of the electrochemical unit C9, which is the unit to be measured) generated between the probes P18 and P17 when outputting the control signal Sc, and outputs the voltage value data Dv2 representing the measured value to the processing unit 6.

[0057] like Figure 3 As shown, the voltage measuring unit 4-3, following the instructions of the processing unit 6, measures the voltage (V3 across the electrochemical unit C3, the unit being measured) generated between probes P5 and P6 when no control signal Sc is output, and outputs the voltage value data Dv3, representing the measured value (the voltage value across the two ends), to the processing unit 6. Furthermore, as... Figure 4 As shown, the voltage measuring unit 4-3, following the instructions of the processing unit 6, measures the voltage (V3 across the two ends of the electrochemical unit C8, which is the unit to be measured) generated between the probes P16 and P15 when outputting the control signal Sc, and outputs the voltage value data Dv3 representing the measured value to the processing unit 6.

[0058] like Figure 3 As shown, the voltage measuring unit 4-4, following the instructions of the processing unit 6, measures the voltage (V4 across the electrochemical unit C4, the unit to be measured) generated between probes P7 and P8 when no control signal Sc is output, and outputs the voltage value data Dv4, representing the measured value (the voltage value across the two ends), to the processing unit 6. Furthermore, as... Figure 4 As shown, the voltage measuring unit 4-4, following the instructions of the processing unit 6, measures the voltage (V4 across the two ends of the electrochemical unit C7, which is the unit to be measured) generated between the probes P14 and P13 when outputting the control signal Sc, and outputs the voltage value data Dv4 representing the measured value to the processing unit 6.

[0059] like Figure 3As shown, the voltage measuring unit 4-5, following the instructions of the processing unit 6, measures the voltage (V5 across the electrochemical unit C5, the unit being measured) generated between probes P9 and P10 when no control signal Sc is output, and outputs the voltage value data Dv5, representing the measured value (the voltage value across the two ends), to the processing unit 6. Furthermore, as... Figure 4 As shown, the voltage measuring unit 4-5, following the instructions of the processing unit 6, measures the voltage generated between probes P12 and P11 (the voltage V5 across the two ends of the electrochemical unit C6, which is the unit to be measured) when outputting the control signal Sc, and outputs the voltage value data Dv5 representing the measured value to the processing unit 6. It should be noted that, hereinafter, when not distinguishing between the two-end voltages V1 to V5, it is also referred to as "two-end voltage V", and when not distinguishing between the voltage value data Dv1 to Dv5, it is also referred to as "voltage value data Dv".

[0060] Current sensors 5-1 and 5-2 can be, for example, current sensors disclosed in Japanese Patent Application Publication No. 2014-235045, which are composed of clamp-type galvanometers capable of clamping covered metal wires or other wires in a non-contact manner. Specifically, the current sensor 5 is configured to have two semi-circular magnetic cores 5a and 5b and a magnetic detection element 5c composed of, for example, a Hall element or a fluxgate element, etc., and functions as a clamp-type non-contact current sensor configured in the following way (openable and closable): by operating the operation part (not shown), the magnetic cores 5a and 5b are brought close together to form an annular opening 5d to clamp (insert) the wire; by operating the operation part, the magnetic cores 5a and 5b are separated to release the clamping of the wire. Furthermore, in this current sensor 5, the magnetic detection element 5c detects the magnetic flux generated in the magnetic cores 5a and 5b due to the current flowing through the wire inserted into the opening 5d. This allows for the measurement of the current value of the current flowing through the wire, ranging from DC to high frequencies, and the output of current value data Di representing the measured current value. However, as the current sensor 5, a sensor capable of measuring the current value of high-frequency signals other than DC can be used, or a current sensor configured with a ring core that cannot be opened or closed can be used instead of a clamp-on current sensor.

[0061] The processing unit 6, for example, is composed of a CPU (Central Processing Unit) and comprehensively controls the impedance measuring device 1. Specifically, during impedance measurement, the processing unit 6 controls the measuring current output unit 3 to generate and output a measuring alternating current Im. Furthermore, as described later, during impedance measurement, when the control signal Sc is not output, the processing unit 6 measures (calculates) the impedance of each electrochemical unit C1 to C5 as the measurement target unit; when the control signal Sc is output, the processing unit 6 measures (calculates) the impedance of each electrochemical unit C10 to C6 as the measurement target unit.

[0062] Specifically, the processing unit 6 controls the current sensor 5 to measure the current flowing in the wires (terminals T1 and T11 in this example) inserted into the opening 5d of the current sensor 5 and outputs current value data Di. It also controls each voltage measuring unit 4 to measure the voltage between probes P and output voltage value data Dv. Furthermore, the processing unit 6 inputs the current value data Di output from the current sensor 5 and the voltage value data Dv output from the voltage measuring unit 4. Additionally, the processing unit 6 measures (calculates) the impedance of the measurement target unit based on the input current value data Di and voltage value data Dv. Specifically, the processing unit 6 calculates the current value (I: supply current value) of the measuring AC current Im flowing through the measurement target unit based on the amplitude of the AC current contained in the current value data Di, and calculates the AC voltage (voltage across the terminals) at both ends of each measurement target unit as a voltage value (V) based on the amplitude of the AC voltage contained in the voltage value data Dv. Furthermore, the processing unit 6 calculates the phase difference (θ) between the alternating current and the alternating voltage based on the current value data Di and the voltage value data Dv, that is, the phase difference (θ) between the alternating current flowing through the measurement target unit and the alternating voltage generated at both ends of the measurement target unit. In addition, based on the calculated measurement alternating current Im (I), the alternating voltage (V), and the phase difference (θ), the processing unit 6 measures (calculates) the impedance of the measurement target unit (impedance Z = V / I, R = Z·cosθ, X = Z·sinθ).

[0063] Furthermore, in the first switching state, the processing unit 6 calculates the impedance of a subset of units as the units to be measured, and in the second switching state, it calculates the impedance of all units except the subset of units as the units to be measured. The sum of the impedances of all units to be measured calculated in the first switching state and the sum of the impedances of all units to be measured calculated in the second switching state is used as the impedance of the DUT (that is, all the units to be measured). Specifically, the processing unit 6 calculates the impedance of each electrochemical unit C1 to C5 (a subset of units) measured when the control signal Sc is not output (first switching state) and the sum of the impedances of each electrochemical unit C10 to C6 (all units except the subset of units) measured when the control signal Sc is output (second switching state) as the overall impedance of the DUT (impedance between terminals T1 to T11).

[0064] Furthermore, processing unit 6, following instructions from the operation unit (not shown in the diagram), outputs a frequency control signal Sf to the measurement current output unit 3, causing the frequency of the measurement AC current Im to scan between the low-frequency band and the high-frequency band. Additionally, processing unit 6 outputs display data Dd to output unit 7, which displays the frequency characteristics of the measured object unit's impedance, the overall impedance of the measured object DUT, and impedances such as the Cole-Cole diagram and Bode diagram (described later).

[0065] As an example, the output unit 7 is composed of a display device (display) such as a liquid crystal panel or an organic EL (electroluminescent) panel. It inputs the display data Dd output from the processing unit 6 and displays the impedance of the measurement object unit, the impedance of the measurement object DUT as a whole, and the frequency characteristics of the impedance on the screen. It should be noted that the output unit 7 can also be configured as an interface device for data communication with an external device instead of a display device, outputting impedance data representing the impedance of the measurement object unit, the impedance of the measurement object DUT as a whole, and the frequency characteristics of the impedance to the external device.

[0066] Probes Pi1, Pi2, and Pi3 are contact-type probes that are connected (in contact) to terminals T of the target device (DUT) to supply a measurement AC current Im. In this case, probes Pi1, Pi2, and Pi3 are connected to terminals T21, T22, and T23 of the scanning unit 2. Furthermore, probes P1 to P20 are contact-type probes used to measure AC voltage, which is the voltage generated between terminals T when the measurement AC current Im is supplied to the target device unit after each tip is connected (in contact) to terminal T. In this case, probes P1 to P20 are connected to terminals T31 to T50 of the scanning unit 2.

[0067] Next, referring to the accompanying drawings, the impedance measurement method for measuring the impedance of each electrochemical unit C1 to C10 and the impedance of the DUT as a whole using the impedance measuring device 1 will be described.

[0068] First, the method for measuring the impedance of a portion of the ten electrochemical units C1 to 10 within the target device DUT (five of the ten electrochemical units C in this example) will be described. It should be noted that the power supply device PD is connected via a connecting line to a pair of connection points defined on each pair of terminals. In this example, the power supply device PD is connected via a power line Lp, which serves as the connecting line, to a pair of connection points Pc1 and Pc2 defined on each pair of terminals T1 and T11. In this case, as a pair of terminals, wires may be connected to the pair of terminals T1 and T11 and extended, with a pair of connection points defined on each of these extended wires.

[0069] Next, probes Pi1, Pi2, and Pi3 are connected. In this case, probe Pi1 is connected to a current supply point designated on either side of a pair of terminals, and probe Pi3 is connected to the other current supply point. In this example, probe Pi1 is connected to a current supply point Ps1 designated on the side of terminal T1 (an example of one terminal in a pair). Furthermore, probe Pi2 is connected to a current supply point Ps2 designated on the side of terminal T11 (an example of the other terminal in a pair). Additionally, probe Pi3 is connected to terminal T6 (an example of another current supply point) at the connection point of the series-connected electrochemical units C5 and C6. In this case, terminal T6 functions as another current supply point Ps3. It should be noted that, similar to connection points Pc1 and Pc2, as a pair of terminals, wires can be connected to and extended from terminals T1, T6, and T11, with each extended wire defining a current supply point.

[0070] Next, connect probe P1 to terminal T1 of the DUT being measured, connect probes P2 and P3 to terminal T2, connect probes P4 and P5 to terminal T3, connect probes P6 and P7 to terminal T4, connect probes P8 and P9 to terminal T5, connect probes P10 and P11 to terminal T6, connect probes P12 and P13 to terminal T7, connect probes P14 and P15 to terminal T8, connect probes P16 and P17 to terminal T9, connect probes P18 and P19 to terminal T10, and connect probe P20 to terminal T11.

[0071] Next, a current sensor 5-1 is positioned between a connection point Pc1 (terminal T1 in this example) on the side of either of the pair of connection points PC1 and PC2, and a measuring current supply point Ps1 that functions as a measuring current supply point in the first switching state, and an electrochemical unit C1 connected to terminal T1 (which is one of the terminals). Furthermore, a current sensor 5-2 is positioned between a connection point Pc2 (terminal T11 in this example) on the side of the other terminal of the pair of connection points Pc1 and Pc2, and a measuring current supply point Ps2 that functions as a measuring current supply point in the second switching state, and an electrochemical unit C10 connected to terminal T11 (another example of a terminal) in the second switching state. The current sensor 5-2 clamps terminal T11.

[0072] In this connection state, firstly, the five electrochemical units C1 to C5 within the target DUT are used as the target units for measurement, and the impedance between the two ends of each electrochemical unit C1 to C5 is measured. At this time, the measurement start switch (not shown in the diagram) is activated. Consequently, the processing unit 6 outputs a frequency control signal Sf to control the measurement current output unit 3 to output the measurement AC current Im, and stops the output of the control signal Sc. In this state, the scanning unit 2 enters a first switching state, therefore each switch S1, S2, S11 to S20 connects the fixed contact c to the movable contact a. Therefore, as... Figure 3 As shown, a pair of inputs of voltage measuring unit 4-1 are connected to the two ends of electrochemical unit C1, a pair of inputs of voltage measuring unit 4-2 are connected to the two ends of electrochemical unit C2, a pair of inputs of voltage measuring unit 4-3 are connected to the two ends of electrochemical unit C3, a pair of inputs of voltage measuring unit 4-4 are connected to the two ends of electrochemical unit C4, and a pair of inputs of voltage measuring unit 4-5 are connected to the two ends of electrochemical unit C5.

[0073] In addition, the measuring AC current Im output from the measuring current output unit 3 is supplied between the measuring current supply point Ps1 and the terminal T6 of the measured object DUT. In this state, the AC current Im used for measurement is divided into: the current value I1 flowing in the current path IR1 formed by one output section of the current measurement output section 3, the current measurement supply line Li, the scanning section 2, the probe Pi1, the current measurement supply point Ps1, the terminal T1, the electrochemical units C1 to C5, the terminal T6 of the target DUT, the probe Pi3, the scanning section 2, the current measurement supply line Li, and the other output section of the current measurement output section 3; and the current value I2 flowing in the current path IR2 formed by one output section of the current measurement output section 3, the current measurement supply line Li, the scanning section 2, the probe Pi1, the current measurement supply point Ps1, the terminal T1, the connection point Pc1, the power line Lp, the power supply device PD, the power line Lp, the connection point Pc2, the terminal T11, the electrochemical units C10 to C6, the terminal T6 of the target DUT, the probe Pi3, the scanning section 2, the current measurement supply line Li, and the other output section of the current measurement output section 3. It should be noted that the DC current output from the power supply device PD flows through connection points Pc1 and Pc2 into the electrochemical units C1 to C10 within the test object DUT. In other words, the power line Lp becomes the active line supplying the DC current.

[0074] In this case, the impedance of the power supply device PD is extremely small, but the impedance of the five electrochemical units C10 to C6 becomes sufficiently large. Therefore, regarding the measuring AC current Im shunted into the current path IR2 including the power supply device PD, since it includes the five electrochemical units C10 to C6 connected in series within the current path IR2, the current value I2 becomes sufficiently small compared to the large current value flowing in the short-circuit state excluding the electrochemical units C10 to C6. On the other hand, the current value I1 of the measuring AC current Im shunted into the five electrochemical units C1 to C5 becomes approximately the same as the current value I2. That is, the current value I2 of the measuring AC current Im shunted into the power supply device PD becomes smaller, and the current value I1 of the measuring AC current Im shunted into the electrochemical units C1 to C5 correspondingly becomes larger. As a result, the voltage values ​​V generated at each of the two ends of the electrochemical units C1 to C5 become larger. Therefore, the ratio (S / N) of the signal level (S) of the measured alternating current Im to the noise level (N) of the voltage across the terminals V measured by each voltage measuring unit 4 is improved, thus enabling high-precision impedance measurement during the impedance calculation process described later by the processing unit 6. At this time, the current sensor 5-1 measures the current value flowing in the terminal T1 inserted (clamped) into the opening 5d. In this case, the current sensor 5-1 measures the current value of the direct current output from the power supply device PD and flowing within the test object DUT, and the current value I1 of the measured alternating current Im flowing in the electrochemical units C1 to C5, and outputs the current value data Di to the processing unit 6.

[0075] In addition, voltage measuring unit 4-1 measures the voltage V1 (voltage across two ends) across electrochemical unit C1 and outputs the voltage value data Dv1 to processing unit 6; voltage measuring unit 4-2 measures the voltage V2 (voltage across two ends) across electrochemical unit C2 and outputs the voltage value data Dv2 to processing unit 6; voltage measuring unit 4-3 measures the voltage V3 (voltage across two ends) across electrochemical unit C3 and outputs the voltage value data Dv3 to processing unit 6; voltage measuring unit 4-4 measures the voltage V4 (voltage across two ends) across electrochemical unit C4 and outputs the voltage value data Dv4 to processing unit 6; and voltage measuring unit 4-5 measures the voltage V5 (voltage across two ends) across electrochemical unit C5 and outputs the voltage value data Dv5 to processing unit 6.

[0076] Next, the processing unit 6 inputs the current value data Di output from the current sensor 5-1 and the voltage value data Dv output from each voltage measuring unit 4. Furthermore, the processing unit 6 measures (calculates) the impedance of the measurement target units C1 to C5 based on the input current value data Di and voltage value data Dv.

[0077] Specifically, firstly, the processing unit 6 corrects the current value shown in the current value data Di by subtracting the current value of the direct current from the data representing the current value (the current value of the direct current and the current value I1 of the measuring alternating current Im) contained in the current value data Di. Thus, the current value represented by the corrected current value data Di becomes the current value I (supply current value) of the measuring alternating current Im flowing only in electrochemical units C1 to C5. It should be noted that when no direct current flows in the target device DUT, and when the current sensor 5-1 is a current sensor that does not detect direct current, the current value represented by the current value data Di is only the current value I1 of the measuring alternating current Im; therefore, it is not necessary to subtract the current value of the direct current from the current value data Di to correct the current value represented by the current value data Di.

[0078] Furthermore, the processing unit 6 calculates the current value (I) of the measuring AC current Im flowing in the electrochemical units C1 to C5 based on the amplitude of the measuring AC current Im contained in the corrected current value data Di, and calculates the voltage (V) of each terminal of the electrochemical units C1 to C5, i.e., the AC voltage, based on the amplitude of the AC voltage contained in the voltage value data Dv1 to Dv5. In addition, the processing unit 6 calculates the phase difference (θ) between the AC current and the AC voltage based on the corrected current value data Di and the voltage value data Dv, i.e., the phase difference (θ) between the AC current (measuring AC current Im) flowing in the electrochemical units C1 to C5, which are the units to be measured, and the respective AC voltages generated at the terminals of each electrochemical unit C1 to C5, which are the units to be measured. Furthermore, based on the calculated current value (I), voltage value (V), and phase difference (θ), the processing unit 6 measures (calculates) the impedances of each of the electrochemical units C1 to C5, which are the units to be measured (impedance Z = V / I, R = Z·cosθ, X = Z·sinθ).

[0079] Furthermore, the processing unit 6 outputs a frequency control signal Sf to the current measurement output unit 3, thereby scanning the frequency of the measuring AC current Im. Then, the processing unit 6 measures (calculates) the impedances of the electrochemical units C1 to C5, which are the units to be measured, at multiple frequencies as described above. Next, the processing unit 6 acquires the frequency characteristics of the impedances of the electrochemical units C1 to C5, which are the units to be measured, at multiple frequencies. In this case, the processing unit 6 acquires the Cole-Cole plot, which represents the impedance characteristics of the electrochemical unit C relative to the frequency, and the Bode plot, which represents the gain characteristics and phase characteristics relative to the frequency, as frequency characteristics. Afterward, the processing unit 6 outputs display data Dd to the output unit 7, and displays the measured impedances of the electrochemical units C1 to C5, the acquired Cole-Cole plot, and the Bode plot on the display device of the output unit 7. In summary, the processing unit 6 completes the measurement processing of the impedances of the electrochemical units C1 to C5, which are the units to be measured.

[0080] Next, the method for measuring the impedance of each electrochemical unit C10 to C6, excluding the aforementioned electrochemical units C1 to C5, will be described. It should be noted that, in the following descriptions of the processing and impedance measurement methods of the impedance measuring device 1, repeated descriptions of the same processing and measurement methods as in the examples described above will be omitted.

[0081] At this time, the processing unit 6 outputs a control signal Sc to the scanning unit 2. In this state, the scanning unit 2 enters a second switching state, therefore each switch S1, S2, S11 to S20 connects the fixed contact c to the movable contact b. Therefore, as... Figure 4 As shown, a pair of inputs of voltage measuring unit 4-1 are connected to the two ends of electrochemical unit C10, a pair of inputs of voltage measuring unit 4-2 are connected to the two ends of electrochemical unit C9, a pair of inputs of voltage measuring unit 4-3 are connected to the two ends of electrochemical unit C8, a pair of inputs of voltage measuring unit 4-4 are connected to the two ends of electrochemical unit C7, and a pair of inputs of voltage measuring unit 4-5 are connected to the two ends of electrochemical unit C6.

[0082] In addition, the measuring AC current Im output from the measuring current output unit 3 is supplied between the measuring current supply point Ps2 and the terminal T6 of the measured object DUT. In this state, the AC current Im used for measurement is divided into: the current value I3 flowing in the current path IR3 formed by one output section of the current measurement output section 3, the current measurement supply line Li, the scanning section 2, the probe Pi2, the current measurement supply point Ps2, the terminal T11, the electrochemical units C10 to C6, the terminal T6 of the target DUT, the probe Pi3, the scanning section 2, the current measurement supply line Li, and the other output section of the current measurement output section 3; and the current value I4 flowing in the current path IR4 formed by one output section of the current measurement output section 3, the scanning section 2, the probe Pi2, the current measurement supply point Ps2, the terminal T11, the connection point Pc2, the power line Lp, the power supply device PD, the power line Lp, the connection point Pc1, the terminal T1, the electrochemical units C1 to C5, the terminal T6 of the target DUT, the probe Pi3, the scanning section 2, the current measurement supply line Li, and the other output section of the current measurement output section 3. It should be noted that the DC current output from the power supply device PD flows through connection points Pc1 and Pc2 into the electrochemical units C1 to C10 within the test object DUT. In other words, the power line Lp becomes the active line supplying the DC current.

[0083] In this case, the impedance of the power supply device PD is extremely small, but the impedance of the five electrochemical units C1 to C5 becomes sufficiently large. Therefore, regarding the measuring AC current Im flowing in the current path IR4, which includes the power supply device PD, the current value I4 becomes sufficiently small compared to the large current value flowing in the short-circuit state excluding the electrochemical units C1 to C5, since it includes the five electrochemical units C1 to C5 connected in series within the current path IR4. On the other hand, the current value I3 of the measuring AC current Im flowing in the five electrochemical units C10 to C6 becomes approximately the same as the current value I4. That is, the current value I4 of the measuring AC current Im shunted to the power supply device PD becomes smaller, and the current value I3 of the measuring AC current Im shunted to the electrochemical units C10 to C6 becomes correspondingly larger. As a result, the voltage values ​​V generated at each of the two ends of the electrochemical units C10 to C6 become larger. Therefore, the ratio (S / N, signal-to-noise ratio) of the signal level (S) of the AC current Im used for measurement to the noise level (N) of the voltage V across the terminals measured by each voltage measuring unit 4 is improved, thus enabling high-precision impedance measurement during the impedance calculation process described later by the processing unit 6. At this time, the current sensor 5-2 measures the current value flowing in the terminal T11 that is inserted (clamped) into the opening 5d. In this case, the current sensor 5-2 measures the current value of the DC current output from the power supply device PD and flowing in the measurement object DUT, and the current value I3 of the AC current Im used for measurement flowing in the electrochemical units C10 to C6, and outputs the current value data Di to the processing unit 6.

[0084] In addition, voltage measuring unit 4-1 measures the voltage V1 (voltage across two ends) across electrochemical unit C10 and outputs the voltage value data Dv1 to processing unit 6; voltage measuring unit 4-2 measures the voltage V2 (voltage across two ends) across electrochemical unit C9 and outputs the voltage value data Dv2 to processing unit 6; voltage measuring unit 4-3 measures the voltage V3 (voltage across two ends) across electrochemical unit C8 and outputs the voltage value data Dv3 to processing unit 6; voltage measuring unit 4-4 measures the voltage V4 (voltage across two ends) across electrochemical unit C7 and outputs the voltage value data Dv4 to processing unit 6; and voltage measuring unit 4-5 measures the voltage V5 (voltage across two ends) across electrochemical unit C6 and outputs the voltage value data Dv5 to processing unit 6.

[0085] Next, the processing unit 6 inputs the current value data Di output from the current sensor 5-2 and the voltage value data Dv output from each voltage measuring unit 4. Furthermore, the processing unit 6 measures (calculates) the impedance of the measurement target units C10 to C6 based on the input current value data Di and voltage value data Dv.

[0086] Specifically, firstly, the processing unit 6 corrects the current value represented by the current value data Di, just as it would when measuring electrochemical units C1 to C5 as the measurement target units. As a result, the current value represented by the corrected current value data Di becomes the current value I3 (supply current value) of the measuring alternating current Im that flows only in electrochemical units C10 to C6.

[0087] Furthermore, the processing unit 6 calculates the current value (I) of the measuring AC current Im flowing in the electrochemical units C10 to C6 based on the amplitude of the measuring AC current Im contained in the corrected current value data Di, and calculates the voltage (V) of each terminal of the electrochemical units C10 to C6, i.e., the AC voltage, based on the amplitude of the AC voltage contained in the voltage value data Dv1 to Dv5. In addition, the processing unit 6 calculates the phase difference (θ) between the AC current and the AC voltage based on the corrected current value data Di and the voltage value data Dv, i.e., the phase difference (θ) between the AC current (measuring AC current Im) flowing in the electrochemical units C10 to C6, which are the units to be measured, and the respective AC voltages generated at the terminals of each electrochemical unit C10 to C6, which are the units to be measured. Furthermore, based on the calculated current value (I), voltage value (V), and phase difference (θ), the processing unit 6 measures (calculates) the impedances (impedance Z=V / I, R=Z·cosθ, X=Z·sinθ) of the electrochemical units C10 to C6, which are the units to be measured.

[0088] Furthermore, similar to when measuring electrochemical units C1 to C5 as the target units, processing unit 6 scans the frequency of the measuring alternating current Im to obtain the frequency characteristics (such as the Cole-Cole plot and Bode plot) of the impedance of electrochemical units C10 to C6 as the target units. Then, processing unit 6 outputs display data Dd to output unit 7, displaying the measured impedances of electrochemical units C10 to C6, along with the obtained Cole-Cole plot and Bode plot, on the display device of output unit 7. In summary, processing unit 6 completes the measurement of the impedances of electrochemical units C10 to C6 as the target units.

[0089] Furthermore, the processing unit 6 calculates the impedance of the DUT as the sum of the impedances of all electrochemical units C1 to C5 (the units to be measured) calculated in the first switching state and the impedances of all electrochemical units C10 to C6 (the units to be measured) calculated in the second switching state. Next, based on the frequency characteristics of the impedances of the electrochemical units C10 to C6 (the units to be measured), the processing unit 6 acquires the frequency characteristics (such as the Cole-Cole plot and Bode plot) of the DUT's impedance at each frequency. Then, the processing unit 6 outputs the display data Dd to the output unit 7, displaying the measured impedance of the DUT, the acquired Cole-Cole plot, and the Bode plot on the display device of the output unit 7. In summary, the processing unit 6 completes the measurement of the impedance of the DUT.

[0090] In this impedance measuring device 1 and impedance measuring method, a measuring alternating current Im is supplied to the target unit via a pair of measuring current supply lines Li, which are respectively connected to one measuring current supply point and the other measuring current supply point in a current path (current path IR1 or current path IR3) between one measuring current supply point (connection point Pc1 or connection point Pc2 in this example) and the other measuring current supply point (connection point Pc3 in this example), including the target unit (electrochemical units C1 to C5 or electrochemical units C10 to C6 in this example). The current supply point is connected to the connection point (terminal T6) of any two units (electrochemical unit C5 and electrochemical unit C6 in this example) that are connected in series among multiple electrochemical units C1 to C10. The first current sensor (current sensor 5-1 in this example) is configured at the connection point (connection point Pc1 in this example) on the side of either of the pair of connection points Pc1 and Pc2, and a current measurement supply point (current measurement supply point Ps1 in this example) is connected to the unit (electrochemical unit C1) connected to either terminal (terminal T1 in this example).

[0091] Therefore, according to the impedance measuring device 1 and the impedance measuring method, even when a low-impedance non-measured object (power supply device PD in this example) is connected in parallel with a measured object DUT configured to have multiple electrochemical units C1 to C10, by using a portion of the multiple electrochemical units C1 to C10 (electrochemical units C1 to C5 in this example) as the measured object unit, a measuring AC current Im can be supplied to the measured object unit. As a result, the supply current value (current value data Di) of the measuring AC current Im flowing only in the measured object unit (electrochemical units C1 to C5 in this example) and the voltage value of the voltage across the measured object unit when the measuring AC current Im is supplied to the measured object unit can be measured. Therefore, the impedance of the measured object unit (electrochemical units C1 to C5 in this example) can be reliably measured.

[0092] Furthermore, in this impedance measuring device 1 and impedance measuring method, a portion of the multiple units (electrochemical units C1 to C5 in this example) are used as the target units for measurement. A measuring current Im is supplied to the target units via a measuring current supply line Li, which is connected to one measuring current supply point (Ps1 in this example) and another measuring current supply point (Ps3 in this example) on the side of one of a pair of terminals (terminals T1 and T11 in this example). Therefore, the current path IR2 through which the measuring current Im flows through the power supply line Lp includes one or more target units with sufficiently high impedance (five electrochemical units C10 to C6 in this example). Thus, even if the power supply device PD has low impedance, the overall impedance of the current path IR2 becomes high. Therefore, according to the impedance measuring device 1 and the impedance measuring method, the current value of the measuring AC current Im flowing through the power supply device PD can be reduced, and the supply current value of the measuring AC current Im flowing through the measured object unit (electrochemical units C1 to C5 in this example) can be increased accordingly. As a result, the voltage value of the voltage across the measured object unit can be increased. Thus, according to the impedance measuring device 1 and the impedance measuring method, the ratio (S / N) of the signal level (S) to the noise level (N) of the measured voltage across the two ends can be sufficiently improved, and the impedance of the measured object unit can be measured with sufficiently high accuracy.

[0093] Furthermore, according to the impedance measuring device 1 and the impedance measuring method, the power supply device PD is taken as the non-measurement object and the electrolysis device is taken as the measurement object DUT. A portion of the multiple electrochemical units C1 to C10 in the electrolysis device (electrochemical units C1 to C5 or electrochemical units C10 to C6 in this example) is taken as the measurement object unit to measure the impedance. Thus, when the power supply device PD with extremely low output impedance is connected in parallel with the measurement object DUT, the impedance of the measurement object unit (electrochemical units C1 to C5 or electrochemical units C10 to C6 in this example) can be reliably measured.

[0094] Furthermore, the impedance measuring device 1 includes: a switch S1 that switches between a first switching state and a second switching state, wherein the first switching state is a state in which any terminal (in this example, terminal T1 or terminal T11) is used as one of a pair of terminals (in this example, terminal T1 or terminal T11), and the second switching state is a state in which any terminal is used as the other terminal of a pair of terminals (in this example, terminal T11); and switches S11 to S20 that switch the measurement target units (in this example, electrochemical units C1 to C5 or electrochemical units C10 to C6) connected to the voltage measuring unit (in this example, voltage measuring units 4-1 to 4-5). The processing unit 6 controls the switching of switches S1 and S11 to S20, thereby automatically switching the connection between the voltage measuring unit and the measurement target units divided into two groups, without the need for manual connection of the voltage measuring unit and the measurement target units.

[0095] Furthermore, according to the impedance measuring device 1, the processing unit 6 calculates the impedance of the target unit (electrochemical units C1 to C5 in this example) calculated in the first switching state and the impedance of the target unit (electrochemical units C10 to C6 in this example) calculated in the second switching state as the impedance of the target DUT. Thus, the impedance of the target DUT (that is, all the target units) can be calculated by performing only two impedance measurements.

[0096] Furthermore, in this impedance measuring device 1, a first current sensor (current sensor 5-1 in this example) is disposed on one terminal side (terminal T1 in this example). The impedance measuring device 1 includes: a second current sensor (current sensor 5-2 in this example) disposed on the other terminal side (terminal T11 in this example) to measure the supply current value of the measuring AC current Im supplied to the measurement target unit; and a third switch (switch S2 in this example) to switch between the supply current value (current value data Di in this example) measured by the first current sensor (current sensor 5-1 in this example) and the supply current value (current value data Di in this example) measured by the second current sensor (current sensor 5-2 in this example) and output them to the processing unit 6. The second current sensor (current sensor 5-2 in this example) is disposed at a pair of connection points (in In this example, the connection point (connection point Pc2) is specified on the other terminal side (terminal T11 in this example) of the connection point Pc1 and the connection point Pc2. In the second switching state, a current supply point (connection point Pc2 in this example) is connected to the unit (electrochemical unit C10) connected to the other terminal (terminal T11 in this example). The processing unit 6 performs switching control on the third switch (switch S2 in this example). Thus, when the first switch (switch S1 in this example) is switched to the first switching state, the supply current value (current value data Di in this example) measured by the first current sensor (current sensor 5-1 in this example) is input. When the first switch is switched to the second switching state, the supply current value (current value data Di in this example) measured by the second current sensor (current sensor 5-2 in this example) is input.

[0097] Therefore, according to the impedance measuring device 1, two current sensors 5-1 and 5-2 are used, so there is no need to remove the current sensor 5-1 to use as the current sensor 5-2. The processing unit 6 controls the switching of the switch S2, so that the supply current value (current value data Di in this example) measured by the current sensor 5-1 and the supply current value (current value data Di in this example) measured by the current sensor 5-2 can be input automatically in a short time.

[0098] Furthermore, according to the impedance measuring device 1 and the impedance measuring method, a non-contact current sensor configured as an openable and closable clamp is used, thereby allowing the first current sensor to be mounted at any position in the DUT being measured.

[0099] Furthermore, based on the impedance measuring device 1 and the impedance measuring method, the frequency characteristics of the impedance of the target unit (electrochemical units C1 to C10 in this example) at multiple frequencies can be obtained, thereby enabling the determination of the performance and degradation of the target unit.

[0100] Furthermore, based on the impedance measuring device 1 and the impedance measuring method, the frequency characteristics of the impedance of the DUT at multiple frequencies can be obtained, thereby enabling the determination of the performance and degradation of the DUT.

[0101] Furthermore, based on the impedance measurement device 1 and the impedance measurement method, either the Cole-Cole plot or the Bode plot can be obtained as the frequency characteristic, thereby enabling high-precision identification of the performance and degradation related to the measured unit and the measured DUT.

[0102] It should be noted that the present invention is not limited to the above embodiments and can be appropriately modified. For example, in the above embodiments, five of the ten electrochemical units C1 to C10 are used as the measurement target units in a single impedance measurement, but this is not limited to this. In a single impedance measurement, a portion (one or more but no more than nine) of all the electrochemical units C1 to C10 can be used. In this case, in a single impedance measurement, half of the multiple electrochemical units C constituting the measurement target DUT are used as the measurement target units, thereby allowing the impedance of all electrochemical units C to be measured in a short time by performing only two impedance measurements.

[0103] Furthermore, examples were given of measuring the voltage V1 across electrochemical units C1 and C10 using voltage measuring unit 4-1, measuring the voltage V2 across electrochemical units C2 and C9 using voltage measuring unit 4-2, measuring the voltage V3 across electrochemical units C3 and C8 using voltage measuring unit 4-3, measuring the voltage V4 across electrochemical units C4 and C7 using voltage measuring unit 4-4, and measuring the voltage V5 across electrochemical units C5 and C6 using voltage measuring unit 4-5. However, it can also be configured such that voltage measuring unit 4-1 measures the voltage V1 across electrochemical units C1 and C6, voltage measuring unit 4-2 measures the voltage V2 across electrochemical units C2 and C7, voltage measuring unit 4-3 measures the voltage V3 across electrochemical units C3 and C8, voltage measuring unit 4-4 measures the voltage V4 across electrochemical units C4 and C9, and voltage measuring unit 4-5 measures the voltage V5 across electrochemical units C5 and C10.

[0104] Furthermore, an example using two current sensors 5-1 and 5-2 has been described, but it is also possible to configure the system to use only one current sensor 5-1 without using current sensor 5-2. In this case, current sensor 5-1 is configured as a clamp-on non-contact current sensor that can be opened and closed. Therefore, in the second switching state, current sensor 5-1 is opened and removed, and clamped in the position of current sensor 5-2, thereby enabling the measurement current value of the AC current Im supplied during the second switching state to be measured.

[0105] Furthermore, while an example of the current sensor 5 outputting current value data Di has been described, it can also be configured such that the current sensor 5 outputs a current measurement signal as an analog signal, and the processing unit 6 measures (operates) the impedance based on the input current measurement signal. Similarly, it can also be configured such that the voltage measurement unit 4 outputs a voltage measurement signal as an analog signal, and the processing unit 6 measures (operates) the impedance based on the input voltage measurement signal.

[0106] Furthermore, in the above embodiments, the first and second current sensors are configured as non-contact current sensors capable of opening and closing clamps. However, shunt resistors can also be used to configure the first and second current sensors. In this case, by connecting wires to terminals T1 and T11 and placing a shunt resistor in the middle of the wires, the supply current value of the measuring AC current Im can be measured.

[0107] Furthermore, in the above embodiments, examples using switches S1, S2, S11 to S20 were described, but in configurations where connection switching is performed manually, configurations in which these switches S1, S2, S11 to S20 are omitted may also be adopted.

[0108] Furthermore, examples of measuring the impedance of each electrochemical unit C have been described, but the method is not limited to this. For example, when it is only necessary to measure the impedance of the target DUT (all electrochemical units C1 to C10), the impedance of the electrochemical units C1 to C5 as a whole can be measured by measuring the voltage values ​​across the terminals of electrochemical units C1 to C5 using a voltage measuring unit 4, and the impedance of the electrochemical units C10 to C6 as a whole can be measured by measuring the voltage values ​​across the terminals of electrochemical units C10 to C6 using the same voltage measuring unit 4. The sum of the measured impedances is then used as the impedance of the target DUT. Moreover, the impedance of the multiple electrochemical units C as a whole can be measured by measuring the voltage values ​​across the terminals of multiple electrochemical units C out of ten electrochemical units C using a voltage measuring unit 4. Furthermore, in the above embodiments, examples of measuring the impedance of all electrochemical units C have been described, but the impedance of only specific electrochemical units C can also be measured.

[0109] Furthermore, in the above embodiments, another measurement current supply point (measurement current supply point Ps3 in this example) is specified at the connection point of two electrochemical units C5 and C6 connected in series, so that the measurement target unit (electrochemical units C1 to C5 or electrochemical units C10 to C6 in this example) is included in the current path (current path IR1 or current path IR3 in this example) between this other measurement current supply point and one measurement current supply point (measurement current supply point Ps1 or measurement current supply point Ps2 in this example), but is not limited to this example. As long as the measurement target unit is included in the current path, it is acceptable. For example, when electrochemical units C1 to C5 are used as measurement target units, the other measurement current supply point (measurement current supply point Ps3) can be specified at the connection point of any one of the two electrochemical units C6 and C7, two electrochemical units C7 and C8, two electrochemical units C8 and C9, and two electrochemical units C9 and C10 connected in series. Similarly, for example, when electrochemical units C10 to C6 are used as the measurement target units, another measurement current supply point (measurement current supply point Ps3) can be specified at the connection point of any one of the two electrochemical units C5 and C4, two electrochemical units C4 and C3, two electrochemical units C3 and C2, and two electrochemical units C2 and C1 connected in series. However, when measuring the impedance of some or all of the electrochemical units C by two impedance measurements, it is preferable to specify the connection point of the two electrochemical units C and C (in this example, electrochemical units C5 and C6) located on the central side of the measurement target DUT in each impedance measurement, as this eliminates the need to switch the connection between the probe Pi3 and the terminals of the measurement target DUT.

[0110] Furthermore, while the examples described above use an electrolysis apparatus as the DUT to be measured, electrolytic reduction apparatuses, devices using ion exchange membranes, fuel cells, lithium-ion batteries, and lead-acid batteries can also be used as DUTs to be measured. It should be noted that, as an electrolytic reduction apparatus, an organic electrolytic reduction apparatus used in the production of MCH (methylcyclohexane), one of the hydrogen carriers, is known (see Japanese Patent Application Publication No. 2022-30943).

[0111] Industrial availability According to the invention of this application, even when a non-measuring object with low impedance is connected in parallel with the measuring object, by using a portion of the multiple impedance elements as the measuring object impedance element, a measuring alternating current Im can be supplied to the measuring object impedance element. As a result, the current value of the measuring alternating current flowing only in the measuring object impedance element and the voltage value across the measuring object impedance element can be measured, thus reliably measuring the impedance of the measuring object impedance element. Therefore, the invention of this application can be widely applied to impedance measuring devices and impedance measuring methods for such impedance measurement.

[0112] Explanation of reference numerals in the attached figures 1: Impedance measuring device; 2: Scanning unit; 3: Measure the current output section; 4-1~4-5: Voltage measuring section; 5-1, 5-2: Current sensors; 6: Processing Department; C1~C10: Electrochemical units; Di: Current value data; DUT: Measurement Object; Dv1~Dv5: Voltage value data; Lc: Connecting wire; Li: Measurement current supply line; Pc1, Pc2: Connection points; PD: Power supply unit; Ps1~Ps3: Measurement current supply points.

Claims

1. An impedance measuring device, comprising: The measurement current supply section supplies, to a part of the plurality of impedance elements as measurement object impedance elements, an alternating current for measurement, in a state in which a non-measurement object is connected in parallel to the measurement object via a connection line, with respect to a measurement object configured to have a plurality of impedance elements connected in series between a pair of terminals, wherein The connecting line is connected to a pair of connection points specified on each of the pair of terminals, and the measuring current supply line is connected to one measuring current supply point and the other measuring current supply point specified on either of the pair of terminals. The first current sensor measures the supply current value of the measuring alternating current supplied to the impedance element of the object being measured. The voltage measuring unit measures the voltage value across the two ends of the impedance element being measured. as well as The processing unit calculates the impedance of the measured impedance element based on the measured supply current value and the voltage value across the terminals. In the impedance measuring device The measuring current supply unit supplies the measuring alternating current to the measuring impedance element via a pair of measuring current supply lines respectively connected to one measuring current supply point and the other measuring current supply point in a manner that includes the impedance element of the object being measured within the current path between the one measuring current supply point and the other measuring current supply point. The other measuring current supply point is connected to the connection point of any two of the plurality of impedance elements that are connected in series. The first current sensor is disposed between the connection point specified on the side of either terminal of the pair of connection points and the current measuring point and the impedance element connected to either terminal.

2. The impedance measuring device according to claim 1, wherein, The impedance is measured by taking the power supply device as the non-measured object and either the electrolysis device or the electrolytic reduction device having multiple impedance elements as the measured object, and taking a portion of the multiple impedance elements as the measured object impedance elements.

3. The impedance measuring device according to claim 1, wherein, The impedance measuring device includes: A first switch switches between a first switching state and a second switching state, wherein the first switching state is a state in which any one terminal is used as one of the terminals in the pair, and the second switching state is a state in which any one terminal is used as the other terminal in the pair; and The second switch switches the impedance element of the measurement object connected to the voltage measuring unit. The processing unit controls the switching between the first switch and the second switch.

4. The impedance measuring device according to claim 3, wherein, In the first switching state, the processing unit calculates the impedance of the target impedance element by treating a portion of the impedance elements as the target impedance elements, and in the second switching state, it calculates the impedance of the target impedance element by treating all the impedance elements other than the portion of impedance elements as the target impedance elements, and calculates the impedance of the target impedance element by taking the sum of the impedance of all the target impedance elements calculated in the first switching state and the impedance of all the target impedance elements calculated in the second switching state as the impedance of the target.

5. The impedance measuring device according to claim 3, wherein, The first current sensor is disposed on the terminal side. The impedance measuring device includes: A second current sensor, disposed on the other terminal side, measures the supply current value of the measuring AC current supplied to the impedance element of the object being measured. as well as The third switch switches between the supply current value measured by the first current sensor and the supply current value measured by the second current sensor, and outputs the result to the processing unit. The second current sensor is disposed between the connection point specified on the other terminal side of the pair of connection points and the measuring current supply point in the second switching state and the impedance element connected to the other terminal. The processing unit performs switching control on the third switch, thereby inputting the supply current value measured by the first current sensor in the first switching state, and inputting the supply current value measured by the second current sensor in the second switching state.

6. The impedance measuring device according to claim 5, wherein, The first current sensor and the second current sensor are composed of non-contact current sensors configured as clamp-type sensors that can be opened and closed.

7. The impedance measuring device according to claim 1, wherein, The measuring current supply unit is configured to change the frequency of the measuring AC current according to a frequency control signal. The processing unit outputs the frequency control signal to the measuring current supply unit to change the frequency of the measuring AC current, thereby obtaining the frequency characteristics of the impedance of the measuring object impedance element at the plurality of frequencies.

8. The impedance measuring device according to claim 7, wherein, The processing unit obtains the frequency characteristics of the impedance of the object being measured based on the frequency characteristics of the impedance of the impedance element of the object being measured.

9. The impedance measuring device according to claim 7 or 8, wherein, The processing unit acquires either the Cole-Cole plot or the Bode plot as the frequency characteristic.

10. An impedance measurement method, wherein, For a test object configured to have multiple impedance elements connected in series between a pair of terminals, with a non-test object connected in parallel to the test object via a connecting line, a portion of the multiple impedance elements are used as the test object impedance elements. A measuring alternating current is supplied to the test object impedance elements via a measuring current supply line. The connecting line is connected to a pair of connection points defined on each of the pair of terminals, and the measuring current supply line is connected to one measuring current supply point and another measuring current supply point defined on either of the pair of terminals. A first current sensor is used to measure the supply current value of the measuring alternating current supplied to the impedance element of the object being measured. The voltage value across the two ends of the impedance element being measured is determined. The impedance of the measured impedance element is determined based on the measured supply current value and the voltage value across the two terminals. In the impedance measurement method described above The measuring alternating current is supplied to the measuring impedance element via a pair of measuring current supply lines, each connected in a manner that includes the impedance element of the object being measured within the current path between the one measuring current supply point and the other measuring current supply point, wherein the other measuring current supply point is connected to the connection point of any two of the plurality of impedance elements connected in series. The first current sensor is disposed between the connection point specified on the side of either terminal in the pair of connection points and the impedance element connected to the either terminal, and the supply current value of the measuring AC current supplied to the impedance element to be measured is measured.

11. The impedance measurement method according to claim 10, wherein, The impedance is measured by taking the power supply device as the non-measured object and either the electrolysis device or the electrolytic reduction device having multiple impedance elements as the measured object, and taking a portion of the multiple impedance elements as the measured object impedance elements.

12. The impedance measurement method according to claim 10, wherein, The first current sensor is a non-contact current sensor configured as an openable and closable clamp.

13. The impedance measurement method according to claim 10, wherein, The frequency characteristics of the impedance of the measured impedance element are obtained at multiple frequencies.

14. The impedance measurement method according to claim 13, wherein, The frequency characteristics of the impedance of the measured object are obtained based on the frequency characteristics of the impedance of the measured object's impedance element.

15. The impedance measurement method according to claim 13 or 14, wherein, Take either the Cole-Cole plot or the Bode plot as the frequency characteristic.

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