Measurement device, measurement method, and program

Abstract

To efficiently measure the frequency characteristics of an object to be measured.SOLUTION: A measurement device 1 detects a response current generated in an object to be measured 9 each time the frequency of an applied voltage V having an AC component applied to the object to be measured 9 is successively increased within a predetermined frequency range. The measurement device 1 selects a set voltage value Vs for the applied voltage V, sets the voltage value of the applied voltage V to the set voltage value Vs, and sets the frequency of the applied voltage V to an upper limit frequency Fu of the predetermined frequency range. The measurement device 1 detects a signal generated in the object to be measured 9 while the set applied voltage V is applied to the object to be measured 9, and if the detected signal does not meet a predetermined condition, changes the set voltage value Vs to a voltage value lower than the set voltage value Vs and lowers the set voltage value Vs until the detected signal meets the predetermined condition. If the detected signal meets the predetermined condition, the measurement device 1 determines the set voltage value Vs as a voltage value at which the frequency of the applied voltage V can be swept.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a measuring device, a measuring method, and a program.

Background Art

[0002] Patent Document 1 discloses a device that calculates circuit constants optimal as an equivalent circuit using impedance data measured by an impedance measuring device.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As the above-described impedance measuring device, there are many devices that detect a response current generated in a measurement object while gradually increasing the frequency of a voltage applied to the measurement object in a predetermined frequency range. In such a measuring device, since the impedance of the measurement object decreases as the frequency of the applied voltage increases, when the frequency of the applied voltage is increased, the impedance of the measurement object at that frequency becomes too small, and it may become impossible to detect the response current. In such a case, there has been a problem that the time required for measurement so far and the time required for impedance measurement in the frequency range where detection has become impossible are wasted.

[0005] The present invention has been made paying attention to such problems, and an object thereof is to efficiently measure the frequency characteristics of a measurement object.

Means for Solving the Problems

[0006] According to an aspect of the present invention, a measuring device detects a response current generated in a measurement object each time the frequency of an applied voltage having an alternating current component applied to the measurement object is sequentially increased within a predetermined frequency range. The measuring device includes a selection means for selecting a set voltage value of the applied voltage, a setting means for setting the voltage value of the applied voltage to the set voltage value and setting the frequency of the applied voltage to the upper limit frequency of the predetermined frequency range, and a detection means for detecting a signal generated in the measurement object in a state where the applied voltage set by the setting means is applied to the measurement object. Further, when the signal does not reach a predetermined condition, the measuring device includes a changing means for changing the set voltage value to a voltage value lower than the set voltage value and lowering the set voltage value until the signal detected by the detection means reaches the predetermined condition, and when the signal reaches the predetermined condition, the measuring device includes a determining means for determining the set voltage value as a voltage value at which the frequency of the applied voltage can be swept.

Advantages of the Invention

[0007] According to this configuration, a set voltage value at which the frequency can be swept is determined before executing a measurement process of detecting a response current each time the frequency of the applied voltage is sequentially increased. Therefore, during the execution of the measurement process, when the frequency of the applied voltage is increased, it is possible to suppress a situation where the impedance of the measurement object at that frequency becomes too small and the response current cannot be detected.

[0008] For this reason, for example, it is less likely that the time required for impedance measurement is wasted because the detection of the response current becomes impossible on the high-frequency side of a predetermined frequency range, so that the frequency characteristics of the measurement object can be efficiently measured.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

[0010] Hereinafter, each embodiment of the present invention will be described with reference to the accompanying drawings. In this specification, the same or equivalent elements are denoted by the same reference numerals throughout.

[0011] (First Embodiment) FIG. 1 is a diagram showing the configuration of a measurement system 100 including a measurement device 1 according to the first embodiment.

[0012] The measurement system 100 is a system for measuring the electrical frequency characteristics of a measurement target 9. The measurement system 100 of the first embodiment measures the frequency characteristics of the AC impedance of the measurement target 9 in a state where the measurement target 9 is compressed at a predetermined pressure.

[0013] The measurement target 9 is an object having a resistance component and a capacitance component. For example, a liquid, a mixed liquid in which an insoluble solid substance is mixed with the liquid, and a powder can be mentioned as candidates for the measurement target 9. Examples of the liquid or the mixed liquid include a slurry used in the production of a positive electrode material or a negative electrode material of a battery. Examples of the powder include a powder used in the production of an all-solid-state battery.

[0014] In the first embodiment, the measurement target 9 is a solid electrolyte used in the manufacture of all-solid-state batteries. The measurement system 100 of the first embodiment for measuring the electrical frequency characteristics of the solid electrolyte includes a measurement device 1 including an AC measuring instrument 2 and a compression device 3.

[0015] The compression device 3 is used to enable measurement of the electrical characteristics of the measurement target 9 in a state where the molding pressure for molding the powder of the measurement target 9 for use as a product acts on the measurement target 9. The compression device 3 compresses the measurement target 9 at a predetermined pressure. For example, a pressure of several tens [kN] is applied to the measurement target 9. Depending on the type of the measurement target 9, the predetermined pressure may be several tens or several hundreds [N].

[0016] The compression device 3 of the first embodiment includes a pair of electrode portions 31a and 31b that sandwich the measurement target 9, and a pressurizing portion 32 that applies a high-load pressing force for compressing the measurement target 9 to the pair of electrode portions 31a and 31b.

[0017] First, the measurement target 9 is placed between the pair of electrode portions 31a and 31b by the measurer. As a specific example, the measurement target 9 is accommodated in a housing hole of a die (not shown), and the pair of electrode portions 31a and 31b are inserted into the die and sandwiched between them. In this state, the die, the pair of electrode portions 31a and 31b, and the measurement target 9 are integrally placed on the compression device 3. Then, a pressure is applied to the measurement target 9 in the vertical direction from the electrode portion 31b toward the electrode portion 31a by the pressurizing portion 32.

[0018] In addition, a voltage application cable of the AC measuring instrument 2 is connected to the pair of electrode portions 31a and 31b, and a current detection cable of the AC measuring instrument 2 is connected to the electrode portion 31b.

[0019] The measurement device 1 constitutes a measurement device that detects a response current I generated in the measurement target 9 each time the frequency of an applied voltage V having an AC component applied to the measurement target 9 is sequentially increased within a predetermined frequency range. The measurement device 1 of the first embodiment measures the frequency characteristics of the AC impedance of the measurement target 9 using the detection results of the response current I at each frequency.

[0020] Then, for example, in order to display the frequency characteristics of the AC impedance, the measuring device 1 plots the measurement data on the complex plane to create a complex plane impedance diagram. As an example of the complex plane impedance diagram, a Nyquist diagram with the real part and the imaginary part of the AC impedance as the real axis and the imaginary axis, respectively, can be mentioned.

[0021] The measuring device 1 is realized by, for example, a computer including one or a plurality of processors and a recording medium. The measuring device 1 according to the first embodiment includes an AC measuring device 2, a storage unit 10, a processing unit 20, an operation unit 30, and a display unit 40.

[0022] The AC measuring device 2 applies an applied voltage V to the measurement target 9 and detects a response current I generated in the measurement target 9 in this state. The shape depicted by the signal variation of the applied voltage V may be a sine wave, or may be a waveform such as a rectangular wave or a sawtooth wave. Further, the applied voltage V may be an AC voltage signal, or may be a voltage signal in which an AC component is superimposed on a DC component.

[0023] The AC measuring device 2 calculates a measured value of the AC impedance, which is a complex number impedance, using the voltage value of the applied voltage V and the detected value of the response current I. Here, the voltage value referred to in the first embodiment is the effective value. Instead of the effective value, a representative value such as an average value may be used.

[0024] The AC measuring device 2 measures the AC impedance for each frequency of the applied voltage V by detecting the response current I generated in the measurement target 9 while sweeping the frequency of the voltage applied to the measurement target 9 within a predetermined frequency range. The predetermined frequency range is also referred to as the sweep frequency range hereinafter.

[0025] The AC measuring device 2 according to the first embodiment includes a constant voltage supply circuit that applies an applied voltage V that is constant voltage controlled so that the voltage value of a sine wave is constant as a signal having an AC component to the measurement target 9, and a current detection circuit that detects the magnitude of the AC response current I flowing through the measurement target 9.

[0026] Furthermore, the AC measuring device 2 includes a control circuit that sweeps the frequency of the applied voltage V output from the constant voltage supply circuit. The AC measuring device 2 also includes a voltage detection circuit that detects the voltage between a pair of electrode portions 31a and 31b sandwiching the measurement target 9, that is, the magnitude of the voltage generated in the measurement target 9, and an output current detection circuit that detects the magnitude of the output current of the voltage supply circuit.

[0027] The sweep frequency range is set, for example, from several [Hz] to several [MHz], and the set voltage value of the applied voltage V is set, for example, from several [mV] to several hundred [mV]. The AC measuring device 2 outputs a group of measured values of the AC impedance at each measured frequency to the processing unit 20 as measurement data indicating the frequency characteristics of the AC impedance. The measurement data shows measured values at frequencies of about 500, for example.

[0028] The storage unit 10 stores the measurement data by the AC measuring device 2 and the calculation results by the processing unit 20. The storage unit 10 of the first embodiment stores the set voltage value of the applied voltage V and the sweep frequency range of the applied voltage V. The set voltage value and the sweep frequency range are determined by the measurer via the operation unit 30, for example.

[0029] The storage unit 10 constitutes a computer-readable recording medium that records a program for controlling the operation of the processing unit 20. The storage unit 10 is realized by a memory such as a ROM (Read Only Memory) and a RAM (Random Access Memory), for example.

[0030] The processing unit 20 executes an AC impedance measurement process for measuring the electrical frequency characteristics of the measurement target 9 based on the measurement data output from the AC measuring device 2. Also, the processing unit 20 of the first embodiment determines the set voltage value of the applied voltage V that can measure the AC impedance over the sweep frequency range by controlling the AC measuring device 2 before executing the AC impedance measurement process.

[0031] The processing unit 20 is realized by a processor such as a CPU (Central Processing Unit), an MPU (Micro Processing Unit), or a DSP (digital signal processor).

[0032] The operation unit 30 is realized by a plurality of push buttons provided around the display screen, a touch sensor arranged within the screen of the display unit 40, or a keyboard and a mouse, etc. The operation unit 30 receives an input operation by a user and generates an operation signal indicating the content of the received input operation.

[0033] Examples of the input operation include an operation of pressing a power button, an operation of setting measurement conditions and display conditions, and an operation of instructing the start or end of an AC impedance measurement process, etc. The operation unit 30 outputs the generated operation signal to the processing unit 20.

[0034] The display unit 40 displays a measurement result indicating the DC resistance of the measurement target 9 or measurement conditions, etc. The display unit 40 is configured by a touch panel, for example, so that a user can visually recognize information and operate it. Alternatively, the display unit 40 may be realized by a liquid crystal display or an LED display, etc. The display unit 40 functions as output means for outputting the calculation result by the processing unit 20.

[0035] As described above, the measurement system 100 according to the first embodiment can measure the electrical characteristics of a powder of a measurement target 9 with a high molding pressure as a product in a state conforming to the actual product state.

[0036] In the first embodiment, an example in which a powder is used as the measurement target 9 has been described. However, the measurement target 9 is not limited to this, and may be an object measurable by the AC measuring device 2 and a liquid and a mixture that do not require the compression device 3. Further, in the first embodiment, the compression device 3 is configured separately from the measuring device 1, but the measuring device 1 may be provided with the compression device 3.

[0037] Next, the detailed configuration of the processing unit 20 will be described with reference to FIG. 2.

[0038] FIG. 2 is a block diagram showing the functional configuration of the processing unit 20 in the measuring apparatus 1 according to the first embodiment.

[0039] The processing unit 20 includes a voltage value selection unit 21, an upper limit frequency acquisition unit 22, a set voltage trial unit 23, a detection signal acquisition unit 24, a voltage decrement processing unit 25, a set voltage determination unit 26, and a measurement command unit 27.

[0040] The voltage value selection unit 21 functions as a selection means for selecting a set voltage value from within the sweep frequency range of the applied voltage V.

[0041] The voltage value selection unit 21 in the first embodiment reads and acquires the set voltage value stored in the storage unit 10 in order to select the initial value of the applied voltage V. Alternatively, the voltage value selection unit 21 may accept, as an initial value, the set voltage value selected by the measurer from within the sweep frequency range via the operation unit 30. The voltage value selection unit 21 outputs the acquired set voltage value to the upper limit frequency acquisition unit 22.

[0042] When the upper limit frequency acquisition unit 22 acquires the set voltage value of the applied voltage V from the voltage value selection unit 21, it reads the sweep frequency range from the storage unit 10 and acquires the upper limit frequency of the sweep frequency range. Alternatively, the upper limit frequency acquisition unit 22 may accept the upper limit frequency of the sweep frequency range set by the measurer via the operation unit 30. The upper limit frequency acquisition unit 22 outputs the acquired set voltage value and upper limit frequency to the set voltage trial unit 23.

[0043] The set voltage trial unit 23 functions as a setting means for setting the voltage value of the applied voltage V to the set voltage value and setting the frequency of the applied voltage V to the upper limit frequency of the sweep frequency range.

[0044] The setting voltage trial unit 23 of the first embodiment tries to apply a voltage to the measurement target 9 in order to measure the applied voltage V with the acquired setting voltage value and determine whether or not AC impedance measurement processing can be executed at each frequency within the sweep frequency range.

[0045] Specifically, the setting voltage trial unit 23 outputs the setting voltage value and the upper limit frequency output from the upper limit frequency acquisition unit 22 to the AC measuring device 2. That is, the setting voltage trial unit 23 instructs the AC measuring device 2 to apply the applied voltage V of the acquired setting voltage value to the measurement target 9 at the acquired upper limit frequency.

[0046] Thereby, the AC measuring device 2 applies the applied voltage V of the setting voltage value to the measurement target 9 at the upper limit frequency, and detects an electrical signal generated in the measurement target 9 in this state. For this reason, the AC measuring device 2 functions as a detection means for detecting a signal generated in the measurement target 9 in a state where the applied voltage V set by the upper limit frequency acquisition unit 22 is applied to the measurement target 9.

[0047] Examples of the signal generated in the measurement target 9 include a voltage signal indicating the voltage value of the voltage generated in the measurement target 9, or a current signal indicating the current value of the current flowing through the measurement target 9. As the current signal, in addition to the current flowing through the measurement target 9 itself, the current supplied from the constant voltage supply circuit to the measurement target 9 is included. The AC measuring device 2 of the first embodiment detects a voltage signal indicating the voltage value of the voltage generated in the measurement target 9 as the signal generated in the measurement target 9.

[0048] The detection signal acquisition unit 24 acquires a detection signal that is a signal detected by the AC measuring device 2. The detection signal acquisition unit 24 of the first embodiment acquires a voltage signal indicating the voltage value of the voltage generated in the measurement target 9 as the detection signal, and outputs the acquired voltage signal to the voltage reduction processing unit 25.

[0049] The voltage reduction processing unit 25 functions as a changing means for changing the setting voltage value of the applied voltage V to a voltage value lower than the setting voltage value.

[0050] The voltage reduction processing unit 25 determines whether or not the signal generated in the measurement target 9 reaches a predetermined condition. Examples of the predetermined condition include, for example, a condition as to whether or not the voltage signal generated in the measurement target 9 reaches the set voltage value, and a condition as to whether or not the current signal flowing through the measurement target 9 exceeds the upper limit allowable value.

[0051] By setting the condition in this way, it becomes possible to detect a state in which the AC impedance of the measurement target 9 becomes too low, the current flowing through the measurement target 9 becomes excessive, and the voltage of the measurement target 9 does not rise to the set value. That is. It becomes possible to detect a non-measurable state in which measurement of the AC impedance becomes impossible due to the above-described predetermined condition.

[0052] In the first embodiment, the voltage reduction processing unit 25 determines whether or not the voltage signal of the measurement target 9 reaches the set voltage value. When it is determined that the voltage signal of the measurement target 9 does not reach the set voltage value, the voltage reduction processing unit 25 predicts that the measurement target 9 will be in a non-measurable state, and changes the set voltage value to a value lower than the set voltage value.

[0053] Then, the voltage reduction processing unit 25 outputs the changed set voltage value to the set voltage trial unit 23. Thereby, the set voltage trial unit 23 instructs the AC measuring device 2 to apply the applied voltage V of the changed set voltage value to the measurement target 9 at the upper limit frequency, and the AC measuring device 2 detects the voltage generated in the measurement target 9 to which the applied voltage V of the changed set voltage value is applied. Then, the voltage reduction processing unit 25 determines whether or not the voltage signal detected by the AC measuring device 2 reaches the set voltage value.

[0054] That is, every time the voltage reduction processing unit 25 changes the set voltage value, it determines whether or not the voltage signal of the measurement target 9 reaches the set voltage value, and sequentially lowers the set voltage value until the voltage signal reaches the set voltage value.

[0055] In this way, when the detection signal does not reach the predetermined condition, the voltage reduction processing unit 25 changes the set voltage value of the measurement target 9 to a voltage value lower than the set voltage value and lowers the set voltage value until the detection signal detected by the AC measuring device 2 reaches the predetermined condition.

[0056] When the detection signal reaches a predetermined condition, the set voltage determination unit 26 functions as a determination means for determining the set voltage value as a voltage value whose frequency can be swept for the applied voltage V. The voltage value whose frequency can be swept here means a voltage value for which the AC impedance can be measured over the sweep frequency range.

[0057] In the first embodiment, when the voltage signal of the measurement target 9 reaches the set voltage value, the set voltage determination unit 26 determines that the measurement target 9 can be measured, and determines the set voltage value as a voltage value whose frequency can be swept.

[0058] The set voltage determination unit 26 outputs the determined voltage value whose frequency can be swept to the measurement command unit 27. Alternatively, the set voltage determination unit 26 may output the determined voltage value whose frequency can be swept to the storage unit 10 or the display unit 40. In this case, the voltage value whose frequency can be swept is recorded in the storage unit 10 or displayed on the display unit 40.

[0059] The measurement command unit 27 functions as a control means for setting the voltage value of the applied voltage V to the voltage value determined by the set voltage determination unit 26 and setting the initial start frequency of the applied voltage V to the lower limit frequency of the sweep frequency range.

[0060] When the measurement command unit 27 of the first embodiment acquires a voltage value whose frequency can be swept from the set voltage determination unit 26, it acquires the lower limit frequency of the sweep frequency range from the storage unit 10 and executes an AC impedance measurement process for measuring the frequency characteristics of the AC impedance regarding the measurement target 9. Specifically, the set voltage determination unit 26 outputs the acquired voltage value and the lower limit frequency to the AC measuring device 2 as a start command for the AC impedance measurement process. That is, the measurement command unit 27 instructs the AC measuring device 2 to apply the applied voltage V of the acquired voltage value to the measurement target 9 at the acquired lower limit frequency.

[0061] As a result, the AC measuring device 2 applies the applied voltage V of the acquired voltage value to the measurement target 9 at the lower limit frequency and detects the response current I generated in the measurement target 9 in this state. Then, the AC measuring device 2 calculates the measured value of the AC impedance at the lower limit frequency using the voltage value of the applied voltage V and the current value of the response current I.

[0062] For this reason, the AC measuring device 2 functions as a measuring means for measuring the AC impedance of the measurement target 9 by detecting the response current I generated in the measurement target 9 in a state where the applied voltage V set by the measurement command unit 27 is applied to the measurement target 9.

[0063] Then, the measurement command unit 27 controls the operation of the AC measuring device 2 to measure the AC impedance for each frequency of the applied voltage V by sequentially increasing the frequency of the applied voltage V from the lower limit frequency.

[0064] In the above-described first embodiment, an example in which the AC impedance measurement process is started immediately after acquiring a voltage value capable of frequency sweep from the set voltage determination unit 26 has been described. However, the timing for executing the AC impedance measurement process is not limited to this. For example, the measurement command unit 27 may wait for the execution of the AC impedance measurement process until an operation for instructing the start of the AC impedance measurement process is received at the operation unit 30 after acquiring a voltage value capable of frequency sweep.

[0065] Next, the frequency characteristics of the AC impedance obtained by the AC impedance measurement process will be briefly described with reference to FIG. 3.

[0066] FIG. 3 is a diagram showing an example of the frequency characteristics of the AC impedance regarding the measurement target 9.

[0067] In FIG. 3, a Nyquist diagram having the real axis representing the real part of the AC impedance as the horizontal axis and the imaginary axis representing the imaginary part as the vertical axis, and a Cole-Cole plot diagram in which the sign of the imaginary axis is inverted is shown.

[0068] The Cole-Cole plot shows an arc drawn by the measurement data generated by the AC measuring device 2. In this arc, as the value of the real part of the AC impedance decreases, the frequency of the AC impedance increases.

[0069] Also, the Cole-Cole plot shows the upper limit frequency Fu set in the AC measuring device 2 by the set voltage trial unit 23 and the lower limit frequency Fl set in the AC measuring device 2 by the measurement command unit 27.

[0070] To obtain the frequency characteristics of the AC impedance shown in Fig. 3, the frequency of the applied voltage V is sequentially increased from the lower limit frequency Fl to the upper limit frequency Fu of the sweep frequency range. When performing such measurement processing, when selecting an object such as a powder with unknown electrical characteristics as the measurement target 9, it is often the case that the optimal set voltage value Vs has not been specified in advance.

[0071] Therefore, if the AC impedance measurement process is executed with the applied voltage V of the predetermined set voltage value Vs, the AC impedance may become too low in the high-frequency region near the upper limit frequency Fu, resulting in the inability to detect the response current I.

[0072] As a countermeasure, the measuring device 1 of the first embodiment determines whether it is possible to detect the response current I generated in the measurement target 9 by applying the applied voltage V of the initial set voltage value Vs to the measurement target 9 at the upper limit frequency Fu, and lowers the set voltage value Vs until it becomes a detectable voltage value. Then, since the measuring device 1 sets the voltage value of the applied voltage V to the set voltage value Vs at which the response current I can be detected at the upper limit frequency Fu and executes the AC impedance measurement process, it is possible to suppress the inability to detect the response current I in the high-frequency region.

[0073] Therefore, it is possible to reduce unnecessary impedance measurements, and since the AC impedance of all frequencies in the sweep frequency range can be obtained, it is possible to accurately estimate the electrical characteristics of the measurement target 9.

[0074] Next, a measurement method by the measurement system 100 according to the first embodiment will be described with reference to FIGS. 4 to 6.

[0075] FIG. 4 is a flowchart showing an example of a processing procedure of a measurement method for measuring the frequency characteristics of the AC impedance regarding the measurement target 9. First, an operation for instructing the execution of the measurement impedance process is input by the measurer to the operation unit 30, and the measurement method of the first embodiment is executed.

[0076] In step S1, the compression device 3 compresses the measurement target 9 at a predetermined pressure according to the actual product state.

[0077] In step S2, the measurement device 1 executes a set voltage determination process for determining a voltage value capable of sweeping the frequency of the applied voltage V applied to the measurement target 9 in a state where the measurement target 9 is compressed by the compression device 3. Details of this process will be described later with reference to FIG. 5.

[0078] In step S3, the AC measuring device 2 executes an AC impedance measurement process of the measurement target 9 in a state where the measurement target 9 is compressed by the compression device 3. Details of this process will be described later with reference to FIG. 6.

[0079] When the process of step S3 is completed, a series of processing procedures for the measurement method of the first embodiment ends.

[0080] Subsequently, FIG. 5 is a flowchart showing an example of the set voltage determination process executed in step S2.

[0081] In step S21, the measurement device 1 selects a set voltage value Vs stored in the storage unit 10 from among the settable voltage ranges of the applied voltage V applied to the measurement target 9. The set voltage value Vs is, for example, a voltage value or an initial value predetermined by the measurer. Note that step S21 corresponds to a selection step of selecting the set voltage value Vs of the applied voltage V.

[0082] In step S22, when the set voltage value is selected in step S21, the measuring device 1 acquires the upper limit frequency Fu of the sweep frequency range from the storage unit 10, and sets the voltage value and the frequency of the applied voltage V to the set voltage value Vs and the upper limit frequency Fu, respectively. The sweep frequency range is a predetermined frequency range, for example, a frequency range or an initial value predetermined by the measurer. The upper limit frequency Fu is set to, for example, several [MHz].

[0083] Note that step S22 corresponds to a setting step of setting the voltage value of the applied voltage V to the set voltage value Vs and setting the frequency of the applied voltage V to the upper limit frequency Fu of a predetermined frequency range.

[0084] In step S23, the measuring device 1 detects a voltage signal generated in the measurement target 9 in a state where the applied voltage V with the set voltage value Vs and the upper limit frequency Fu set in step S22 is applied to the measurement target 9. Instead of the voltage signal, the detection target may be a current flowing through the measurement target 9 or a current signal indicating the current value of the output current of a constant voltage supply circuit that supplies a voltage to the measurement target 9.

[0085] Note that step S23 corresponds to a detection step of detecting a signal generated in the measurement target 9 in a state where the applied voltage V set in step S22 is applied to the measurement target 9.

[0086] In step S24, the measuring device 1 determines whether or not the detection signal obtained in step S23 reaches a predetermined condition. Specifically, the measuring device 1 determines whether or not the voltage signal of the measurement target 9 reaches the set voltage value Vs. Instead of this, the measuring device 1 may be configured to determine whether or not the current signal of the measurement target 9 is equal to or less than the upper limit allowable value.

[0087] When the voltage signal does not reach the set voltage value Vs in step S24, the measuring device 1 proceeds to the process of step S25, and when the voltage signal reaches the set voltage value Vs, the measuring device 1 proceeds to the process of step S26.

[0088] In step S25, since the voltage signal of the measurement target 9 does not reach the set voltage value Vs, the measurement device 1 decreases the set voltage value Vs by a predetermined interval ΔV, and sets the voltage value (Vs - ΔV) decreased by the predetermined interval ΔV as the new set voltage value Vs. The predetermined interval ΔV is set in advance to a value within a range from, for example, 0.1 [V] to 0.01 [V].

[0089] Then, the measurement device 1 returns to the process of step S22, detects the voltage signal of the measurement target 9 in a state where the applied voltage V of the upper limit frequency Fu is applied to the measurement target 9 with the new set voltage value Vs, and decreases the set voltage value Vs step by step by the predetermined interval ΔV until the voltage signal reaches the set voltage value Vs.

[0090] Step S25 corresponds to a change step of changing the set voltage value Vs to a voltage value lower than the set voltage value Vs and decreasing the set voltage value Vs until the signal detected in step S23 reaches a predetermined condition when the signal generated in the measurement target 9 in step S24 does not reach the predetermined condition.

[0091] On the other hand, in step S26, since the voltage signal of the measurement target 9 has reached the set voltage value Vs, the measurement device 1 sets the set voltage value Vs as the determination voltage value Vd. The set determination voltage value Vd means a voltage value within the voltage values of the applied voltage V that can be frequency-swept.

[0092] Note that step S26 corresponds to a determination step of determining the set voltage value Vs as a voltage value that can be frequency-swept of the applied voltage V when the signal generated in the measurement target 9 in step S24 reaches a predetermined condition.

[0093] When the process of step S26 is completed, the set voltage determination process of step S2 ends, and the process returns to the processing procedure of the measurement method shown in FIG. 4 and proceeds to the AC impedance measurement process of step S3.

[0094] Subsequently, FIG. 6 is a flowchart showing an example of the AC impedance measurement process executed in step S3.

[0095] First, the determined voltage value Vd obtained in step S26 and the lower limit frequency Fl of the sweep frequency are set in the AC measuring instrument 2 by the measurement command unit 27. For example, the determined voltage value Vd is set to an effective value of several hundred mV, and the lower limit frequency Fl is the lower limit frequency of the sweep frequency range, and is set to, for example, several Hz.

[0096] In step S31, as shown in FIG. 1, the AC measuring instrument 2 applies to the object to be measured 9 an applied voltage V of a lower limit frequency Fl that is constant-voltage controlled to a constant determined voltage value Vd while the object to be measured 9 is in a compressed state in step S1.

[0097] In step S32, the AC measuring instrument 2 detects the AC response current I that flows through the object to be measured 9 in a state in which the applied voltage V is applied to the object to be measured 9 in step S31. Then, the AC measuring instrument 2 measures the AC impedance, which is expressed as a complex number, based on the current value of the detected response current I and the determined voltage value Vd of the applied voltage V.

[0098] In step S33, the AC measuring instrument 2 calculates a measured value of the AC impedance for each frequency of the applied voltage V while gradually increasing the frequency of the applied voltage V within the sweep frequency range.

[0099] In step S34, the AC measuring instrument 2 outputs a group of calculated AC impedance measurement values as measurement data indicating the frequency characteristics of the AC impedance.

[0100] When the process of step S34 is completed, the AC impedance measurement process of step S3 ends, and the process returns to the process procedure shown in FIG. 4, whereupon the series of process procedures for the measurement method of the first embodiment ends.

[0101] Next, the effects of the first embodiment will be described.

[0102] The measurement device 1 in the first embodiment detects a response current I occurring in the object to be measured 9 each time the frequency of the applied voltage V having an AC component applied to the object to be measured 9 is successively increased within a predetermined frequency range.

[0103] This measuring device 1 includes a voltage value selection unit 21 that functions as a selection means for selecting a set voltage value Vs of the applied voltage V, and a set voltage trial unit 23 that functions as a setting means for setting the voltage value of the applied voltage V to the set voltage value Vs and setting the frequency of the applied voltage V to the upper limit frequency Fu within a predetermined frequency range. Then, the measuring device 1 includes an AC measuring instrument 2 that functions as a detection means for detecting a signal generated in the measurement target 9 in a state where the applied voltage V set by the set voltage trial unit 23 is applied to the measurement target 9.

[0104] Furthermore, when the signal detected by the AC measuring instrument 2 does not reach a predetermined condition, the measuring device 1 includes a voltage decrement processing unit 25 that functions as a changing means for changing the set voltage value Vs to a voltage value lower than the set voltage value Vs and decreasing the set voltage value Vs until the signal detected by the AC measuring instrument 2 reaches the predetermined condition. And when the signal detected by the AC measuring instrument 2 reaches the predetermined condition, the measuring device 1 includes a set voltage determination unit 26 that functions as a determination means for determining the set voltage value Vs as a voltage value (Vd) at which the frequency of the applied voltage V can be swept.

[0105] Also, in the measurement method according to the first embodiment, the response current I generated in the measurement target 9 is detected each time the frequency of the applied voltage V having an AC component applied to the measurement target 9 is sequentially increased within a predetermined frequency range.

[0106] This measurement method includes a selection step (S21) of selecting a set voltage value of the applied voltage V, and a setting step (S22) of setting the voltage value of the applied voltage V to the set voltage value Vs and setting the frequency of the applied voltage V to the upper limit frequency within a predetermined frequency range. And the measurement method includes a detection step (23) of detecting a signal generated in the measurement target 9 in a state where the applied voltage V set in step S22 is applied to the measurement target 9.

[0107] Furthermore, when the signal detected in step S23 does not reach a predetermined condition, the measurement method includes a changing step (S24 and S25) of changing the set voltage value Vs to a voltage value lower than the set voltage value Vs and lowering the set voltage value Vs until the signal detected in step S23 reaches the predetermined condition. When the signal detected in step S23 reaches the predetermined condition, the measurement method includes a determining step (S24 and S26) of determining the set voltage value Vs as a voltage value (Vd) capable of frequency-sweeping the applied voltage V.

[0108] Furthermore, the program stored in the storage unit 10 in the first embodiment is a program for executing each step (S21 to S26) included in the above measurement method.

[0109] According to the configurations of these measuring devices 1, measurement methods, and programs, a set voltage value Vs capable of frequency-sweeping is determined before executing a measurement process of detecting the response current I each time the frequency of the applied voltage V is sequentially increased. Therefore, during the execution of the measurement process, when the frequency of the applied voltage V is increased, it is possible to suppress a situation where the impedance of the measurement target 9 at that frequency becomes too small and the response current I cannot be detected.

[0110] For this reason, for example, it is possible to avoid the inability to detect the response current I on the high-frequency side of a predetermined frequency range, so that the time required for impedance measurement on the high-frequency side is not wasted. Therefore, it is possible to efficiently measure the electrical frequency characteristics of the measurement target 9. Also, since the AC impedance can be obtained at all frequencies within the predetermined frequency range, it is possible to accurately estimate the electrical characteristics of the measurement target 9.

[0111] In addition, the measuring device 1 in the first embodiment includes a measurement command unit 27 that functions as control means for setting the voltage value of the applied voltage V to the voltage value Vd determined by the set voltage determination unit 26 and setting the start frequency of the applied voltage V to the lower limit frequency Fl of a predetermined frequency range. Then, the AC measuring device 2 functions as measuring means for measuring the AC impedance of the measurement target 9 by detecting the response current I generated in the measurement target 9 in a state where the applied voltage V set by the measurement command unit 27 is applied to the measurement target 9. At this time, the measurement command unit 27 controls the operation of the AC measuring device 2 so as to sequentially increase the frequency of the applied voltage V from the lower limit frequency Fl and measure the AC impedance for each frequency of the applied voltage V.

[0112] According to this configuration, since the frequency sweep is performed from the lower limit frequency Fl with the applied voltage V of the determined voltage value Vd, even if the frequency of the applied voltage V approaches the upper limit frequency Fu of the sweep frequency range, it is possible to normally measure the AC impedance of the measurement target 9. Thereby, it is possible to avoid a situation where the response current I becomes undetectable during the measurement of the frequency characteristics of the AC impedance and the previous measurements are wasted.

[0113] In addition, since the AC impedance measurement process is continuously executed after the set voltage determination unit 26 determines the voltage value Vd that allows frequency sweeping, it is possible to quickly measure the frequency characteristics of the AC impedance. Therefore, according to the above configuration, it is possible to quickly and efficiently measure the frequency characteristics of the measurement target 9.

[0114] Further, in the first embodiment, the AC measuring device 2 detects the voltage value of the voltage generated in the measurement target 9, and when the voltage value detected by the AC measuring device 2 does not reach the set voltage value Vs as a predetermined condition, the voltage reduction processing unit 25 changes the set voltage value Vs to a voltage value lower than the set voltage value Vs.

[0115] According to this configuration, by adopting a configuration for determining whether or not the voltage generated in the measurement target 9 has reached the set voltage value Vs, it is possible to realize, with a simple configuration, the determination of whether the frequency characteristics of the AC impedance can be measured or not.

[0116] In addition, the measuring device 1 in the first embodiment includes a compression device 3 that functions as a compression means for compressing the measurement target 9, and the AC measuring device 2 measures the frequency characteristics of the AC impedance of the measurement target 9 in a state where the measurement target 9 is compressed by the compression device 3.

[0117] According to this configuration, when the measurement target 9 is an object with a high molding pressure as a product, it becomes possible to measure the AC impedance of the measurement target 9 in a state that conforms to the actual product state. Therefore, it is possible to measure the electrical characteristics of the measurement target 9 in a state that conforms to the product state.

[0118] In addition to this, by setting the voltage value of the applied voltage V to the determination voltage value Vd, it becomes possible to efficiently measure the frequency characteristics of the AC impedance. Therefore, it is possible to reduce the time for unnecessarily compressing the measurement target 9 by the compression device 3. Accordingly, both the compression device 3 and the AC measuring device 2 can be operated efficiently.

[0119] In addition, the measurement target 9 in the first embodiment is a powder containing a solid electrolyte. According to this configuration, it is possible to efficiently measure the electrical frequency characteristics of a battery such as an all-solid-state battery using a powder containing a solid electrolyte as a material.

[0120] (Second Embodiment) In the first embodiment, an example in which the set voltage value Vs is decreased stepwise at a predetermined interval ΔV has been described. However, the method of decreasing the set voltage value Vs is not limited to this. Therefore, another example of the method of decreasing the set voltage value Vs will be described in the following second embodiment.

[0121] The measurement system of the second embodiment is the same as or equivalent to the configuration of the measurement system 100 of the first embodiment shown in FIGS. 1 and 2. Therefore, the same reference numerals are given to the same or equivalent configurations as those in the first embodiment, and duplicate explanations are omitted.

[0122] FIG. 7 is a flowchart showing an example of the processing procedure of the measurement method according to the second embodiment.

[0123] The measurement method according to the second embodiment includes the process of step S2A instead of the set voltage determination process of step S2 in the first embodiment. Since the other processes are the same as those in the first embodiment, the same reference numerals are given and duplicate explanations are omitted. The process of step S2A in the second embodiment includes the processes of steps S31 to S33 instead of the process of step S25 in the first embodiment.

[0124] In step S31, since it is determined in step S24 that the voltage signal of the measurement target 9 has not reached the set voltage value Vs, the voltage reduction processing unit 25 reduces the set voltage value Vs to a voltage value that is half of the set voltage value Vs (Vs÷2). Then, the voltage reduction processing unit 25 sets the voltage value (Vs÷2) as the new set voltage value Vs.

[0125] In step S32, the measurement device 1 determines whether or not the set voltage value Vs changed in step S31 in the voltage reduction processing unit 25 is equal to or higher than the lower limit threshold value Vt. The lower limit threshold value Vt is set to the lower limit of the voltage value of the applied voltage V required to ensure the signal-to-noise ratio (SN ratio) necessary for detecting the response current I in the AC impedance measurement process.

[0126] Then, when the changed set voltage value Vs is equal to or higher than the lower limit threshold value Vt, the measurement device 1 returns to the process of step S22. On the other hand, when the changed set voltage value Vs is less than the lower limit threshold value Vt, since there is no measurable set voltage value Vs, the process of step S2A is terminated and the measurement method is terminated.

[0127] Thus, in steps S31 and S32, when the detection signal does not reach the predetermined condition, the measuring device 1 sets the voltage value that is the minimum required to ensure the SN ratio of the response current I as the lower limit, and changes the set voltage value to half of the voltage value.

[0128] Also, in step S33, since it is determined in step S24 that the voltage signal of the measurement target 9 has reached the set voltage value Vs, the measuring device 1 determines in the set voltage determination unit 26 whether or not the achievement count exceeds a predetermined value.

[0129] The above-mentioned predetermined value is a natural number and is set to "1" in the second embodiment. Therefore, in the second embodiment, the measuring device 1 applies the applied voltage V to the measurement target 9 twice at the same set voltage value Vs, and determines whether or not the voltage signal generated in the measurement target 9 reaches the set voltage value Vs both times each time it is applied.

[0130] If the achievement count is less than or equal to the predetermined value in step S33, the measuring device 1 returns to the process of step S22. On the other hand, if the achievement count exceeds the predetermined value in step S33, the measuring device 1 proceeds to the process of step S26.

[0131] Thus, in steps S33 and S26, the measuring device 1 applies the applied voltage V at the same set voltage value Vs to the measurement target 9 a plurality of times in the set voltage determination unit 26, and when the detection signal reaches the predetermined condition in all the applied states, determines the set voltage value Vs as a voltage value capable of frequency-sweeping the applied voltage V.

[0132] Note that in the example shown in FIG. 7, when the changed set voltage value Vs is less than the lower limit threshold value Vt, the process of step S2A is terminated, but it is not limited thereto. For example, the measuring device 1 may set the lower limit threshold value Vt as the set voltage value Vs in the AC measuring device 2 and determine whether or not the detection signal detected by the AC measuring device 2 reaches the predetermined condition.

[0133] Subsequently, the operation and effect according to the second embodiment will be described.

[0134] In the measuring device 1, measuring method, and program according to the second embodiment, the same or equivalent configurations as those in the first embodiment can obtain the same operational effects as those in the first embodiment.

[0135] In addition, the set voltage determination unit 26 in the second embodiment determines the set voltage value Vs as the determination voltage value Vd of the applied voltage V when the signal detected by the AC measuring device 2 reaches a predetermined condition a plurality of times.

[0136] According to this configuration, the set voltage determination unit 26 adopts the set voltage value Vs as the determination voltage value Vd only when the detection signal reaches a predetermined condition continuously a plurality of times at the same voltage value. In the sweep frequency range of the applied voltage V in impedance measurement, the high-frequency side is particularly likely to have unstable detection results compared to the low-frequency side. For this reason, it is preferable to execute a process of applying the same voltage value to the measurement target 9 and checking whether the detection signal reaches a predetermined condition a plurality of times.

[0137] In this way, by executing the confirmation process of the detection signal a plurality of times, the risk of becoming unmeasurable during the frequency sweep can be reduced compared to the process of adopting the set voltage value Vs as the determination voltage value Vd when the detection signal reaches a predetermined condition only once.

[0138] In addition, when the signal detected by the AC measuring device 2 does not reach a predetermined condition, the voltage reduction processing unit 25 in the second embodiment changes the set voltage value Vs to a half voltage value with the minimum voltage value required to ensure the SN ratio of the response current I as the lower limit.

[0139] According to this configuration, when the detection signal does not reach a predetermined condition, the set voltage value Vs is lowered to half of the voltage value. Therefore, compared with the process of gradually lowering the set voltage value Vs at a predetermined interval ΔV, the set voltage value Vs at which the detection signal reaches the predetermined condition can be efficiently specified. In addition, even when the response current I has an unacceptable signal-to-noise ratio, it is possible to avoid unnecessarily lowering the set voltage value Vs. Therefore, the measuring device 1 of the second embodiment can determine a voltage value that can be frequency-swept more efficiently than the first embodiment.

[0140] As described above, the embodiments of the present invention have been described. However, the above embodiments merely show a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.

Explanation of Reference Numerals

[0141] 100 Measurement system 1 Measuring device 2 AC measuring instrument (detection means, measurement means) 3 Compression device 20 Processing unit 21 Voltage value selection unit (selection means) 23 Set voltage trial unit (setting means) 25 Voltage decreasing processing unit (changing means) 26 Set voltage determination unit (determination means) 27 Measurement command unit (control means) S21~S23 (selection step, setting step, detection step) S24, S25 (changing step) S24, S26 (determination step)

Claims

1. A measuring device that detects a response current generated in a measurement target each time the frequency of an applied voltage having an AC component applied to the measurement target is sequentially increased within a predetermined frequency range, selection means for selecting a set voltage value of the applied voltage; setting means for setting the voltage value of the applied voltage to the set voltage value and setting the frequency of the applied voltage to the upper limit frequency of the predetermined frequency range; detection means for detecting a signal generated in the measurement target with the applied voltage set by the setting means applied to the measurement target; changing means for, when the signal does not reach a predetermined condition, changing the set voltage value to a voltage value lower than the set voltage value and lowering the set voltage value until the signal detected by the detection means reaches the predetermined condition; determination means for, when the signal reaches the predetermined condition, determining the set voltage value as a voltage value at which the frequency of the applied voltage can be swept; A measuring device comprising.

2. The measuring device according to claim 1, control means for setting the voltage value of the applied voltage to the voltage value determined by the determination means and setting the start frequency of the applied voltage to the lower limit frequency of the predetermined frequency range; measurement means for measuring the AC impedance of the measurement target by detecting the response current generated in the measurement target with the applied voltage set by the control means applied to the measurement target, and the control means controls the operation of the measurement means to sequentially increase the frequency of the applied voltage from the lower limit frequency and measure the AC impedance for each frequency of the applied voltage. A measuring device.

3. The measuring device according to claim 1 or 2, the determination means determines the set voltage value as a voltage value at which the frequency can be swept a plurality of times when the signal reaches the predetermined condition. A measuring device.

4. The measuring device according to claim 1, when the signal does not reach a predetermined condition, the changing means changes the set voltage value to a half voltage value with the minimum voltage value required to ensure the signal-to-noise ratio of the response current as the lower limit. A measuring device.

5. The measuring device according to claim 1, the detection means detects the voltage value of the voltage generated in the measurement target. When the voltage value detected by the detection means does not reach the set voltage value as the predetermined condition, the change means changes the set voltage value to a voltage value lower than the set voltage value. Measuring device. **Claim 6** The measuring device according to claim 2, including compression means for compressing the measurement target, wherein the measuring means measures the frequency characteristics of the AC impedance of the measurement target in a state where the measurement target is compressed by the compression means. Measuring device. **Claim 7** The measuring device according to claim 5, wherein the measurement target is a powder containing a solid electrolyte. Measuring device. **Claim 8** A measuring method for detecting a response current generated in the measurement target each time the frequency of an applied voltage having an AC component applied to the measurement target is sequentially increased within a predetermined frequency range, a selection step of selecting a set voltage value of the applied voltage; a setting step of setting the voltage value of the applied voltage to the set voltage value and setting the frequency of the applied voltage to the upper limit frequency of the predetermined frequency range; a detection step of detecting a signal generated in the measurement target in a state where the applied voltage set in the setting step is applied to the measurement target; a change step of changing the set voltage value to a voltage value lower than the set voltage value and lowering the set voltage value until the signal detected in the detection step reaches the predetermined condition when the signal does not reach the predetermined condition; a determination step of determining the set voltage value as a voltage value at which the frequency of the applied voltage can be swept when the signal reaches the predetermined condition; The measuring method comprising the above steps. **Claim 9** In a computer for detecting a response current generated in a measurement target each time the frequency of an applied voltage having an AC component applied to the measurement target is sequentially increased within a predetermined frequency range, a selection step of selecting a set voltage value of the applied voltage; a setting step of setting the voltage value of the applied voltage to the set voltage value and setting the frequency of the applied voltage to the upper limit frequency of the predetermined frequency range; a detection step of detecting a signal generated in the measurement target in a state where the applied voltage set in the setting step is applied to the measurement target; a change step of changing the set voltage value to a voltage value lower than the set voltage value and lowering the set voltage value until the signal detected in the detection step reaches the predetermined condition when the signal does not reach the predetermined condition; When the signal reaches the predetermined condition, a determination step of determining the set voltage value as a voltage value capable of sweeping the frequency of the applied voltage; A program for causing execution.

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