Measurement device and measurement method

Abstract

To properly evaluate the characteristics of powder.SOLUTION: A measurement device 100 includes a die 30 provided with an accommodation hole 31a in which a powder P is accommodated, a pair of electrodes 40a and 40b that are inserted into the accommodation hole 31a and sandwich the powder P, a pressurizing unit 50 that applies a high-load pressurizing force for compressing the powder P to the pair of electrodes 40a and 40b, and a measurement unit 60 that applies an AC signal to the pair of electrodes and measures an impedance of the powder P. Each of the pair of electrodes 40a and 40b includes a plate-shaped flange portion 41a and 41b that have a cross-sectional area larger than a cross-sectional area of the accommodation hole 31a, and a boss portion 42a and 42b protruded from the flange portion 41a and 41b and inserted into the accommodation hole 31a.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a measurement device and a measurement method. [Background technology]

[0002] Patent Document 1 discloses a powder resistivity measuring device that measures the volume resistivity of various powders. In this measuring device, the powder in a cylinder is gradually compressed, and the thickness of the powder in each compressed state is measured with a height gauge, and the resistance value is measured with a probe unit, thereby measuring the volume resistivity relative to the bulk density of the powder in each compressed state. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-179352 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventional powder measuring devices apply a DC signal to a powder to measure its electrical resistance. Such conventional measuring devices cannot measure the AC impedance of the measurement target. In addition, in order to properly evaluate the properties of a powder, it is desirable to measure the electrical properties while the powder is being subjected to a molding pressure that molds the powder for use as a product.

[0005] The present invention has been made in consideration of the above problems, and has an object to provide a measuring device and a measuring method for appropriately evaluating the characteristics of various powders. [Means for solving the problem]

[0006] According to one aspect of the present invention, a measuring device for measuring electrical properties of a powder includes a die having a receiving hole for receiving the powder, a pair of electrodes inserted into the receiving hole to sandwich the powder, a pressure unit applying a high pressure load to the pair of electrodes to compress the powder, and a measuring unit applying an AC signal to the pair of electrodes to measure the impedance of the powder. Each of the pair of electrodes has a plate-shaped flange having a cross-sectional area larger than the cross-sectional area of ​​the receiving hole, and a boss protruding from the flange and inserted into the receiving hole.

[0007] According to one aspect of the present invention, a method for measuring electrical properties of a powder using a measuring device includes the steps of: accommodating the powder in a receiving hole provided in a die that accommodates the powder, compressing the powder by applying a high load pressure to a pair of electrodes that sandwich the powder, and measuring the impedance of the powder by applying an AC signal to the pair of electrodes. Each of the pair of electrodes has a plate-shaped flange portion having a cross-sectional area larger than the cross-sectional area of ​​the receiving hole, and a boss portion that protrudes from the flange portion and is inserted into the receiving hole. Effect of the Invention

[0008] In these embodiments, since an AC signal is applied to the powder to measure the impedance, it is possible to perform characteristic evaluation taking into account the capacitance component of the powder. Also, since a high load pressure is applied to the powder, it is possible to measure the electrical characteristics of powder that is subjected to high molding pressure as a product in a state that matches the actual product state.

[0009] In addition, since the pressure force from the pressure unit can be received by the flange unit having a relatively large pressure receiving area, the durability of the electrode unit can be improved compared to a case in which the flange unit is not provided. Therefore, the durability of the electrode unit can be improved while appropriately evaluating the characteristics of various powders. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a cross-sectional view showing a measuring device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a block diagram showing the measurement device of this embodiment. [Diagram 3] FIG. 3 is an enlarged view showing the periphery of the die of the measuring device of this embodiment. [Figure 4] FIG. 4 is a partial enlarged view of the measurement device for explaining the correction step of the measurement method of this embodiment. [Diagram 5] FIG. 5 is a diagram for explaining the correction process of the measurement method of this embodiment, and is a graph showing the load on the slider on the horizontal axis and the displacement of the slider on the vertical axis. [Figure 6] FIG. 6 is a diagram for explaining the correction information of the open correction in the correction step of this embodiment, and is a graph showing the electrode distance on the horizontal axis and the correction value on the vertical axis. [Figure 7] FIG. 7 is a partial enlarged view of the measuring device for explaining the accommodation step of the measuring method of this embodiment. [Figure 8] FIG. 8 is a diagram for explaining the trigger step in the measurement method of this embodiment, and is a graph showing time on the horizontal axis and slider displacement on the vertical axis. [Figure 9] FIG. 9 is a diagram for explaining the calculation process in the measurement method of this embodiment, and is a graph showing the bulk density of powder P on the horizontal axis and the volume resistivity of powder P on the vertical axis. [Figure 10] FIG. 10 is an enlarged cross-sectional view showing a modification of the measuring device of this embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] A measurement device 100 and a measurement method according to an embodiment of the present invention will be described below with reference to the drawings.

[0012] First, the overall configuration of a measuring device 100 according to an embodiment will be described with reference to Fig. 1 to Fig. 3. Fig. 1 is a cross-sectional view showing the measuring device 100 according to an embodiment. Fig. 2 is a block diagram showing the measuring device 100. Fig. 3 is an enlarged view showing the periphery of a die 30 of the measuring device 100 (part A in Fig. 1).

[0013] The measuring device 100 measures the electrical characteristics of powder P (see FIG. 3, etc.) which is the object to be measured. In this embodiment, a case will be described where the powder P which is the object to be measured is a solid electrolyte used in an all-solid-state battery. The measuring device 100 applies a high load pressure to the powder P to compress the powder P, and measures the impedance of the powder P. Note that the powder P which is the object to be measured is not limited to a solid electrolyte for an all-solid-state battery, and may be any other powder.

[0014] As shown in Figures 1 and 2, the measuring device 100 includes a press device 10 having a pair of electrode units 40a, 40b that apply an electrical signal to the powder P and pressurizes the powder P, a measuring unit 60 that measures electrical characteristics based on the electrical signal applied to the powder P, and a processing unit 70 that processes the measurement results of the measuring unit 60.

[0015] The press device 10 includes a frame 2 mounted on a stand 1 placed on the ground, a slider 20 attached to the frame 2 so as to be movable in the vertical direction, a die 30 provided with a storage hole 31a in which powder P is stored, a pair of electrode portions 40a, 40b inserted into the storage hole 31a in which the die 30 is placed and which moves in the vertical direction to sandwich the powder P, and a pressure section 50 which applies a high load pressure to the pair of electrode portions 40a, 40b to compress the powder P.

[0016] The frame 2 has a pair of tables 3a, 3b spaced apart in the vertical direction, a number of posts (not shown) connecting the pair of tables 3a, 3b, and a pair of guide rods 4 that guide the movement of the slider 20 along the vertical direction. The pair of tables 3a, 3b are connected to each other so as to be immovable relative to each other by, for example, four posts that are provided on all four sides of the slider 20 and extend in the vertical direction. The pair of guide rods 4 each extend in the vertical direction, and both ends are connected to the pair of tables 3a, 3b.

[0017] A pair of sleeves 21, through which the pair of guide rods 4 are inserted, are attached to the slider 20, and the slider 20 slides on the guide rods 4 via the sleeves 21. The slider 20 moves vertically along the guide rods 4 between the pair of tables 3a, 3b.

[0018] As shown in FIG. 3, the die 30 has an inner die 31 in which the receiving hole 31a is formed, and an outer die 35 provided outside the inner die 31.

[0019] The inner die 31 is formed in an annular shape, and a receiving hole 31a, which is a circular through-hole, is provided in the center. The inner die 31 is made of an insulating material. In this embodiment, the inner die 31 is made of a ceramic material that has insulating properties and can withstand high load pressure (press pressure).

[0020] The outer die 35 is formed in an annular shape, and a die receiving hole 35a, which is a circular through hole, is provided in the center. The inner die 31 is attached to the outer die 35 in a state where it is inserted into the die receiving hole 35a. By providing the outer die 35 on the outside of the inner die 31, durability against press pressure can be reinforced. The outer die 35 is desirably formed of a material with excellent durability, such as a metal, regardless of whether it has insulating properties or not.

[0021] The die 30 is not limited to a configuration including the inner die 31 and the outer die 35, and may be composed of one member, or may be composed of three or more members.

[0022] The pair of electrode portions 40a, 40b are formed to have the same shape. One electrode portion 40a is fixed to the upper table 3a by an attachment portion 45a. The other electrode portion 40b is fixed to the slider 20 by an attachment portion 45b. When the slider 20 moves in the vertical direction, the electrode portion 40b attached to the slider 20 moves forward and backward in the vertical direction relative to the other electrode portion 40a. In this manner, the pair of electrode portions 40a, 40b are configured to move relative to each other in the vertical direction.

[0023] Each of the electrodes 40a, 40b has a disk-shaped flange 41a, 41b having a cross-sectional area larger than the cross-sectional area of ​​the receiving hole 31a of the die 30, and a cylindrical boss 42a, 42b protruding from one end face of the flange 41a, 41b along the axial direction and inserted into the receiving hole 31a. The boss 42a, 42b is provided coaxially with the corresponding flange 41a, 41b, and is formed with an outer diameter slightly smaller than the inner diameter of the receiving hole 31a of the die 30. Thus, the electrode 40a, 40b has a cross-sectional shape along the central axis that is substantially T-shaped. The die 30 is placed on the lower electrode 40b with the boss 42b of the lower electrode 40b fixed to the slider 20 inserted into the receiving hole 31a of the inner die 31.

[0024] Gas contained in the powder P compressed by the pair of electrodes 40a, 40b is discharged to the outside of the accommodation hole 31a through a gap between the inner periphery of the accommodation hole 31a of the die 30 and the outer periphery of the boss portions 42a, 42b. The electrode portions 40a, 40b have flange portions 41a, 41b having a larger cross-sectional area than the boss portions 42a, 42b inserted into the accommodation hole 31a, and thus the pressure receiving area for the pressurizing force, which is the contact area with the tables 3a, 3b, can be increased, and durability can be ensured.

[0025] Each of the electrode parts 40a, 40b is formed of a material (e.g., metal) having electrical conductivity. As shown in FIG. 1, an application wiring 71a (source wiring) for guiding an electrical signal from the measurement part 60 and a measurement wiring 72a (sense wiring) for guiding a response signal obtained by applying an electrical signal to the powder P are connected to one of the electrode parts 40a. Similarly, the application wiring 71b and the measurement wiring 72b are connected to the other electrode part 40b. The application wirings 71a, 71b and the measurement wirings 72a, 72b are connected to the electrode parts 40a, 40b via connectors (not shown) attached to the outer circumferential surfaces (cylindrical surfaces) of the flange parts 41a, 41b, respectively. The measurement part 60 performs AC impedance measurement by four-terminal measurement in which signals are communicated by a pair of application wirings 71a, 71b and measurement wirings 72a, 72b. Furthermore, since each electrical wiring (71a, 71b, 72a, 72b) is connected to the outer peripheral surfaces of the flange portions 41a, 41b, rather than to the end faces of the flange portions 41a, 41b of the electrode portions 40a, 40b which receive the pressurized force, the electrode portions 40a, 40b and each electrical wiring (71a, 71b, 72a, 72b) can be stably connected without being affected by the pressurized force.

[0026] Moreover, the pair of electrode parts 40a, 40b receive a pressure from the pressure unit 50 and compress the powder P placed between them in the accommodation hole 31a. That is, the pair of electrode parts 40a, 40b function as electrodes that communicate electric signals with the measurement unit 60, and also function as dies that compress the powder P.

[0027] The mounting portion 45a provided on the upper table 3a has a plate-shaped base portion 46a provided between the upper table 3a and the flange portion 41a of the electrode portion 40a, and a holder portion 47a that is engaged with the flange portion 41a of the electrode portion 40a and attached to the upper table 3a. The base portion 46a is formed to have an outer diameter larger than that of the flange portion 41a of the electrode portion 40a. The base portion 46a and the holder portion 47a of the mounting portion 45a are each formed of an insulator.

[0028] The mounting portion 45b provided on the slider 20, like the mounting portion 45a of the upper table 3a, has a plate-shaped base portion 46b provided between the slider 20 and the flange portion 41b of the electrode portion 40b, and a holder portion 47b engaged with the flange portion 41b of the electrode portion 40b and attached to the slider 20. The base portion 46b is formed to have a larger outer diameter than the flange portion 41b of the electrode portion 40b. The base portion 46b and the holder portion 47b of the mounting portion 45b of the slider 20 are each formed of an insulator.

[0029] The pair of electrodes 40a, 40b are attached to the upper table 3a or the slider 20 via attachment parts 45a, 45b made of an insulator, thereby insulating the pair of electrodes 40a, 40b from the upper table 3a and the slider 20. The attachment parts 45a, 45b may be made of any material as long as it is an insulator. In this embodiment, the insulator used for the attachment parts 45a, 45b is a ceramic material, similar to the inner die 31.

[0030] The pressure unit 50 is a pressure source that applies pressure to the pair of electrode units 40a, 40b, and in this embodiment, is an electric hydraulic jack provided between the lower table 3b and the slider 20. When hydraulic pressure is supplied, the pressure unit 50 extends and applies a pressure force to the slider 20 in the vertical upward direction. The slider 20 receives the pressure from the pressure unit 50 and moves vertically upward together with the die 30 and the electrode unit 40b on the slider 20, and the powder P between the electrode unit 40b attached to the slider 20 and the electrode unit 40a attached to the upper table 3a is compressed by the pressure acting on the powder P. When the pressure is released, the pressure unit 50 contracts due to the weight of the slider 20.

[0031] The pressurizing unit 50 is not limited to a hydraulic jack, but may be a mechanical (screw type) or pneumatic jack. The pressurizing unit 50 is not limited to a jack, but may be of any configuration as long as it can exert a pressing force. In other words, the press device 10 is not limited to a hydraulic type, but may be of another hydraulic type, or may be of a mechanical or electric type.

[0032] The hydraulic jack constituting the pressurizing unit 50 is selected so as to apply a desired pressure to the powder P. In this embodiment, since the powder P, which is a material of the solid electrolyte of the all-solid-state battery, is the measurement target, a hydraulic jack capable of applying a high-load pressure close to the molding pressure of the solid electrolyte to the powder P in the accommodation hole 31a is selected for the area (pressure-receiving area) of the tips of the boss portions 42a, 42b of the pair of electrode portions 40a, 40b that contact the powder P. Specifically, the pressurizing unit 50 is configured to be capable of exerting a high-load pressure to apply a pressure of 750 MPa or more to the powder P in the accommodation hole 31a.

[0033] The measuring unit 60 is an LCR meter that measures inductance, capacitance, resistance, impedance, etc. The measuring unit 60 is not limited to an LCR meter, and may be, for example, a vector network analyzer (VNA). More specifically, the measuring unit 60 applies an AC signal to the pair of electrodes 40a, 40b through application wirings 71a, 71b, and measures the frequency characteristic of the complex impedance based on a response signal transmitted through measurement wirings 72a, 72b.

[0034] The processing unit 70 is a computer equipped with an arithmetic processing device such as a CPU, a storage device, a display device, an input device, a network connection device, etc. The processing unit 70 is electrically connected to the measurement unit 60, and controls the operation of the measurement unit 60 to obtain the measurement results by the measurement unit 60. The processing unit 70 also controls the operation of the pressurizing unit 50. The processing unit 70 performs various processes described in this specification by the CPU executing a program previously stored in the storage device.

[0035] Although the processing unit 70 is configured by one computer, the present invention is not limited to this, and may be configured by a plurality of microcomputers so that each control is distributed among the plurality of computers.

[0036] The press device 10 has a displacement sensor 55 as a displacement measuring unit that measures the relative displacement of the pair of electrode portions 40a, 40b, and a load sensor 57 as a load measuring unit that measures the load applied to the powder P.

[0037] The displacement sensor 55 is a contact-type displacement sensor attached to the lower table 3b via a bracket 56, with the tip of a contactor 55a coming into contact with the lower surface of the slider 20. The displacement sensor 55 measures the displacement of the slider 20, and thus the relative displacement in the vertical direction between the pair of electrode portions 40a, 40b. The displacement sensor 55 may be of another measurement type, such as an optical type. The measurement results of the displacement sensor 55 are input to the processing unit 70.

[0038] The load sensor 57 is, for example, a load cell, and is provided between the pressure unit 50 and the slider 20. The load sensor 57 measures the pressure force (load) applied from the pressure unit 50 to the slider 20. The measurement result of the load sensor 57 is input to the processing unit 70. The measurement results of the displacement sensor 55 and the load sensor 57 are stored in the processing unit 70 in association with each other.

[0039] Next, the measurement method of this embodiment will be described with reference to Figs. 4 to 9. Fig. 4 is a partially enlarged view of the measurement device 100 for explaining the correction process in the measurement method. Fig. 5 is a diagram for explaining the correction process in the measurement method, and is a graph showing the load on the slider 20 on the horizontal axis and the displacement of the slider 20 on the vertical axis. Fig. 6 is a diagram for explaining correction information for open correction in the correction process, and is a graph showing the distance between the pair of electrode parts 40a, 40b on the horizontal axis and the conductance obtained from the real part of the impedance between the pair of electrode parts 40a, 40b in the open state as an example of a correction value on the vertical axis. Fig. 7 is a partially enlarged view of the measurement device 100 for explaining the accommodation process in the measurement method. Fig. 8 is a diagram for explaining the trigger process in the measurement method, and is a graph showing time on the horizontal axis and the displacement of the slider 20 on the vertical axis. Fig. 9 is a diagram for explaining the calculation process in the measurement method, and is a graph showing the bulk density of the powder P on the horizontal axis and the volume resistivity of the powder P on the vertical axis.

[0040] The measurement method of this embodiment includes a step of correcting the measurement results of the displacement sensor 55 (correction step), a step of accommodating the powder P in the accommodation hole 31a provided in the die 30 in which the powder P is accommodated (accommodation step), a step of compressing the powder P by applying a high load pressure to a pair of electrode portions 40a, 40b that sandwich the powder P (compression step), a step of measuring the impedance of the powder P by applying an AC signal to the pair of electrode portions 40a, 40b (impedance measurement step), and a step of acquiring the volume resistivity of the powder P from the volume of the powder P acquired based on the relative displacement of the pair of electrode portions 40a, 40b measured by the displacement measurement unit and the measured impedance (calculation step).

[0041] First, the correction step performed before measuring the electrical characteristics of the powder P will be described.

[0042] [Correction process] In the measurement method of this embodiment, as described below, the volume resistivity of the powder P is obtained. For this purpose, the displacement of the slider 20 is measured by the displacement sensor 55, and the volume of the compressed powder P is obtained from the displacement of the slider 20.

[0043] In the press device 10, when a pressure is applied to the pair of electrode parts 40a, 40b, the powder P in the housing hole 31a of the die 30 is sandwiched between the pair of electrode parts 40a, 40b and compressed, and gas contained in the powder P is discharged to the outside of the die 30. In the process of compressing the powder P in this manner, the volume of the powder P is reduced by discharging the gas, and the pressure force of the pressure part 50 causes deformation (basically elastic deformation) in each component of the press device 10.

[0044] For this reason, the displacement of the slider 20 measured by the displacement sensor 55 includes the displacement due to the deformation of the press device 10 as well as the compression of the powder P. If the volume of the powder P is obtained from the measurement result of the displacement sensor 55 including the displacement due to the deformation of the press device 10, the error from the actual volume will be large, and it will be impossible to obtain the volume resistivity of the powder P with high accuracy.

[0045] Therefore, in the correction process of this embodiment, the reference point (zero point) of the displacement sensor 55 is adjusted, and the amount of deformation of the press device 10 due to the application of pressure is acquired. During the correction process, the displacement of the slider 20 is measured by the displacement sensor 55, and the pressure applied to the slider 20 is measured by the load sensor 57.

[0046] In the correction process, first, as shown in FIG. 4, in an empty state where the powder P is not accommodated in the accommodation hole 31a of the die 30, the slider 20 is moved upward to insert the boss portion 42a of the upper electrode portion 40a into the accommodation hole 31a, and the tips of the boss portions 42a, 42b of the electrode portions 40a, 40b are directly contacted with each other. Then, from the state where the tips of the boss portions 42a, 42b are in contact, a predetermined first load F1 (for example, 1 kN) larger than zero is applied to the electrode portions 40a, 40b based on the measurement result of the load sensor 57, and the value (first measurement result) of the displacement sensor 55 when the first load F1 is applied is set as a reference point (zero point). Next, a second load F2 (for example, the upper limit value of the pressure force that the pressure unit 50 can exert) larger than the first load F1 is applied to the electrode portions 40a, 40b, and the value (second measurement result) of the displacement sensor 55 at that time is obtained. The value of the displacement sensor 55 when the second load F2 is applied indicates the amount of deformation of the press device 10.

[0047] Next, the relationship between the value of the displacement sensor 55 and the load (the value of the load sensor 57) is obtained from the first measurement result (zero) which is the value of the displacement sensor 55 when the first load F1 is applied and the second measurement result which is the value of the displacement sensor 55 when the second load F2 is applied. In this embodiment, since two types of loads, the first load F1 and the second load F2, are applied to the electrode parts 40a and 40b, as shown in FIG. 5, the displacement of the slider 20 and the load applied to the electrode parts 40a and 40b are assumed to have a linear relationship, and the relationship between the displacement of the slider 20 and the load is obtained as a linear slope a (=u2 / (F2-F1)). Note that the magnitude of the applied load may be set to three or more, and the relationship between the displacement of the slider 20 and the load may be obtained as a nonlinear relational expression from the obtained result of the displacement sensor 55. The relationship between the displacement of the slider 20 and the load thus obtained is stored in the processing unit 70.

[0048] By understanding the relationship between the displacement of the slider 20 and the load in advance, it is possible to understand the amount of deformation of the press device 10 when the powder P is compressed with a predetermined load. Therefore, if the measurement result of the load sensor 57 is F and the measurement result of the displacement sensor 55 is u, the thickness t of the powder P can be obtained by the following formula (1). In the subsequent steps, the thickness of the powder P obtained by correcting the measurement result of the displacement sensor 55 in this manner is used.

[0049] (Number 1) t=ua(F-F1)=u-u2·(F-F1) / (F2-F1)···(1)

[0050] It should be noted that such a correction step needs to be performed only once before measuring the electrical characteristics of the powder P, and does not need to be performed every time measuring the electrical characteristics of the powder P. Furthermore, in the case where the deformation of the press device 10 due to the pressure applied to the powder P is negligible in the evaluation of the characteristics of the powder P, the step of acquiring the deformation amount of the press device 10 and correcting the measurement result of the displacement sensor 55 is not essential.

[0051] In addition, in the correction process, in addition to the configuration of the displacement sensor 55, corrections may be made to the processing unit 70, such as open / short correction for correcting the wiring resistance between the processing unit 70 and the electrode units 40a, 40b or the contact resistance between the electrode units 40a, 40b and the powder P.

[0052] For example, correction information indicating the relationship between the distance between the pair of electrodes 40a, 40b and a correction value for open correction is stored in advance in the processing unit 70. As the correction value for open correction, for example, at least one of the real part and the imaginary part of the impedance at a specific frequency in an open state where the pair of electrodes 40a, 40b are open is used.

[0053] The specific frequency referred to here is one or a plurality of frequencies within a predetermined frequency range required for measuring the impedance of the powder P. Examples of the real part of the impedance include resistance R and conductance G, and examples of the imaginary part of the impedance include reactance X and susceptance B. In this embodiment, the conductance G of the specific frequency in the open state is used as a correction value for open correction.

[0054] The processing unit 70 refers to the previously stored correction information when acquiring the impedance measurement result of the powder P at a specific frequency obtained by applying an AC signal to the powder P in an impedance measurement step described below and the thickness of the powder P at the time of measurement. As a result, the processing unit 70 obtains a correction value corresponding to the thickness of the powder P acquired as the distance between the pair of electrodes 40a, 40b, and corrects the impedance measurement result of the powder P using the correction value. Specifically, the processing unit 70 corrects the impedance measurement result of the powder P at each frequency within a predetermined frequency range by referring to the correction information for multiple frequencies.

[0055] In detail, when the processing unit 70 acquires the measurement result Zm of the impedance of the powder P for each frequency of the AC signal, it refers to the correction information to determine the correction value Yo corresponding to the thickness of the powder P at the time of measurement. Then, the processing unit 70 acquires the corrected measurement result Zx by substituting the measurement result Zm and the correction value Yo into, for example, the following formula (2).

[0056] (Number 2) Zm = 1 / (Yo + 1 / Zx) (2)

[0057] In this way, when the impedance of the powder P is measured by the measuring unit 60, the processing unit 70 refers to the above-mentioned correction information and acquires a correction value corresponding to the distance between the pair of electrode units 40a, 40b acquired from the relative displacement measured by the displacement sensor 55. Then, the processing unit 70 corrects the measurement result of the impedance of the powder P using the acquired correction value.

[0058] Here, an example of a method for acquiring the correction information will be described.

[0059] 4, in an empty state in which no powder P is accommodated in the accommodation hole 31a of the die 30, the slider 20 is moved upward to insert the boss portion 42a of the upper electrode portion 40a into the accommodation hole 31a, and the tips of the boss portions 42a, 42b of the electrode portions 40a, 40b are brought into direct contact with each other. Then, from the state in which the tips of the boss portions 42a, 42b are in contact, the slider 20 is moved downward in stages to measure the real and imaginary parts of the impedance between the pair of electrode portions 40a, 40b in the open state.

[0060] Next, using these measurement results, a correction value is obtained for each interval between the pair of electrode parts 40a, 40b, and the relationship between the interval between the pair of electrode parts 40a, 40b and the correction value is obtained. In this embodiment, as shown in Fig. 6, a nonlinear relational expression indicating the correspondence relationship between the interval between the pair of electrode parts 40a, 40b and the conductance G including the real part of the impedance at a specific frequency between the pair of electrode parts 40a, 40b in the open state is obtained as the correction information. In the example shown in Fig. 6, the conductance G when the measurement frequency is 4k [Hz] is shown as the correction value.

[0061] As the correction information, instead of the relational expression showing the relationship between the distance between the pair of electrodes 40a, 40b and the impedance measurement result at a specific frequency in the open state, a correspondence table showing the relationship may be generated. The correction information obtained in this manner is stored in the processing unit 70.

[0062] In this way, the measurement unit 60 measures the impedance in the open state every time the spacing between the pair of electrode units 40a, 40b is changed by the pressurizing unit 50 in a state in which no powder P is contained. Then, the processing unit 70 generates and stores the above-mentioned correction information based on the measurement results of the impedance in the open state measured by the measurement unit 60 for each spacing 40a, 40b between the pair of electrode units. The correction information may be obtained through testing, simulation, or the like.

[0063] Next, the process of actually measuring the electrical characteristics of the powder P will be described.

[0064] [Containment process] In a preparation state before the measurement of the electrical characteristics of the powder P, the pressurizing unit 50 does not exert a pressing force and re-shrinks due to the weight of the slider 20. In the preparation state, the die 30 on the slider 20 is retracted from the upper electrode portions 40a, 40b, and the boss portions 42a, 42b of the upper electrode portions 40a, 40b are not inserted into the accommodation hole 31a of the die 30 and are separated therefrom.

[0065] In the accommodation step, as shown in Fig. 7, powder P is charged into the accommodation hole 31a of the die 30 of the press device 10 in such a prepared state. The mass of the charged powder P is measured in advance and stored in the processing unit 70. In the accommodation step, the die 30 and the pair of electrode parts 40a, 40b may be removed from the press device 10 (table 3a, slider 20), the boss part 42b of the lower electrode part 40b is inserted into the accommodation hole 31a of the die 30, the powder P is charged into the accommodation hole 31a, the boss part 42a of the upper electrode part 40a is inserted into the accommodation hole 31a, and then the die 30 and the pair of electrode parts 40a, 40b may be attached to the press device 10 with the powder P charged.

[0066] [Compression process] The powder P is put into the receiving hole 31a of the die 30 by the receiving step, and the compression step is started when, for example, an operator operates a measurement start button (not shown). Furthermore, when the compression step is started, measurements by the displacement sensor 55 and the load sensor 57 are each started.

[0067] In the compression step, the operation of the pressure unit 50 is controlled by a control signal from the processing unit 70, and the pressure unit 50 applies a pressure force to the slider 20. This causes the slider 20 to move vertically upward. As the slider 20 moves upward, the bosses 42a, 42b of the upper electrode portions 40a, 40b are inserted into the accommodation hole 31a of the die 30 and eventually come into contact with the powder P in the accommodation hole 31a. As the slider 20 is further pressurized upward from this state, the powder P sandwiched between the pair of electrode portions 40a, 40b is compressed by the pressure force (see FIG. 3).

[0068] When a stop signal is sent from the processing section 70 to the pressure section 50, the pressure exerted by the pressure section 50 is reduced, and the pressure section 50 contracts due to the weight of the slider 20. When the pressure section 50 contracts to its full extent and the press device 10 returns to the ready state, the compression process is completed.

[0069] During such a compression step, the processing unit 70 performs a measurement trigger step of issuing a trigger to start an impedance measurement step, which will be described later.

[0070] The measurement trigger process will now be described.

[0071] Normally, powder P contains gas, so in the early stages of compressing powder P, the volume of powder P changes greatly and the inclusion of gas makes it unsuitable for measuring the electrical characteristics of powder P. When the gas contained in powder P is discharged, the change in thickness of powder P becomes smaller, as shown in Figure 8. In the measurement trigger process, this reduction in the change in thickness of powder P (point T in the figure) is detected and a trigger for impedance measurement is issued.

[0072] More specifically, as described above, the measurement results of the displacement sensor 55 and the load sensor 57 are input and stored in the processing unit 70 at predetermined time intervals (sampling intervals). When the measurement result of the displacement sensor 55 is input, the processing unit 70 calculates the amount of change in displacement of the slider 20 per unit time (hereinafter simply referred to as the "amount of displacement change") based on the measurement result of the displacement sensor 55.

[0073] When the amount of change in displacement of the slider 20 is calculated, the processing unit 70 compares the amount of change in displacement with a threshold value previously stored in the processing unit 70. Then, when the amount of change in displacement of the slider 20 falls below the threshold value, a command signal for executing an impedance measurement process is sent to the measuring unit 60. In this way, a trigger for starting the impedance measurement is issued.

[0074] Alternatively, in the measurement trigger step, for example, a trigger for impedance measurement may be issued after it is detected that the change in impedance of the powder P has become small.

[0075] More specifically, first, the measurement results of the measurement unit 60 are input to and stored in the processing unit 70 at a predetermined time interval before the impedance measurement step is executed. Therefore, when the measurement results of the measurement unit 60 are input to the processing unit 70, the processing unit 70 calculates the amount of change per unit time of the impedance of the powder P based on the measurement results of the measurement unit 60. For example, the processing unit 70 calculates the difference between the previous measurement result input from the measurement unit 60 and the current measurement result as the amount of change per unit time of the impedance of the powder P.

[0076] Then, when the processing unit 70 calculates the amount of change in impedance, it compares the amount of change in impedance with another threshold value previously stored in the processing unit 70. Then, when the amount of change in impedance falls below the other threshold value, it transmits a command signal to the measurement unit 60 to execute an impedance measurement process. In this way, a trigger to start the impedance measurement is issued.

[0077] The processing unit 70 may transmit a command signal to the measuring unit 60 to execute the impedance measurement process only when the amount of change in displacement of the slider 20 falls below a threshold and the amount of change in impedance falls below another threshold. In this manner, a trigger to start the impedance measurement is issued.

[0078] [Impedance measurement process] In the impedance measuring step, which is performed by being triggered by the processing unit 70, an AC signal is applied to the powder P, and the impedance of the powder P is measured as an electrical characteristic.

[0079] In this embodiment, a predetermined AC voltage is applied to the pair of electrodes 40a, 40b as an AC signal from the measuring unit 60 while sweeping the frequency in a predetermined frequency range, and the value of the current flowing between the electrodes 40a, 40b is detected to measure the impedance of the powder P. The measurement result is resolved into, for example, a real part and an imaginary part of the impedance and used for equivalent circuit analysis, etc. The frequency range to be swept is set according to the measurement target, and in this embodiment, it is set, for example, from 4 Hz to 8 MHz.

[0080] The results of the impedance measurement are stored in the storage unit in association with the frequency of the AC voltage and the displacement of the slider 20. When the impedance measurement is completed over the entire range of the predetermined frequency band, a control signal indicating the end of the impedance measurement process is sent from the measurement unit 60 to the processing unit 70. In response to this control signal, the processing unit 70 stops the application of pressure by the pressure unit 50 and ends the compression process. In other words, the impedance measurement process is performed in parallel with the compression process.

[0081] The impedance measurement process is triggered when the displacement change amount of the slider 20 falls below a set value and the volume change of the powder P is detected to be small, so that the measurement can be started immediately when the gas is discharged from the powder P and the powder P becomes stable. Even if the impedance measurement is performed in a state where the powder P contains gas, the impedance of the powder P itself cannot be accurately measured due to the gas contained in the powder P. In addition, if the measurement is not performed even though the gas is discharged from the powder P and the powder P becomes stable, time is wasted and the work efficiency decreases. The impedance measurement process is triggered at an appropriate timing by the measurement trigger process, so that the impedance of the powder P can be measured accurately and efficiently. Furthermore, since the impedance measurement process is automatically triggered based on the measurement result of the displacement sensor 55, the reproducibility during repeated measurements can be improved.

[0082] In addition, the impedance measuring step may be performed by applying an AC current as an AC signal to the pair of electrodes 40a, 40b. Also, the frequency sweep configuration is not essential, and impedance measurement may be performed only at a specific frequency.

[0083] In addition, when the impedance of powder P is sequentially measured while sweeping the frequency of the AC signal within a predetermined frequency range, the processing unit 70 may detect that the change in impedance of powder P has become smaller each time the frequency of the AC signal is changed, and may issue a trigger for impedance measurement.

[0084] Specifically, each time the frequency of the AC signal is changed, the processing unit 70 compares the change in impedance of the powder P per unit time with another threshold value, as described above, and when the change in impedance falls below the other threshold value, it sends a command signal to the measurement unit 60 to perform impedance measurement at the next frequency.

[0085] In this manner, in the impedance measurement process, when the frequency of the AC signal is set and the amount of change in impedance of the powder P per unit time becomes equal to or less than a predetermined threshold value, measurement of the impedance may be started.

[0086] [Calculation process] In the calculation step, the pressure (pressing pressure) applied to the powder P, the bulk density of the powder P in the receiving hole 31a of the die 30, and the volume resistivity and electrical conductivity of the powder P are calculated by the processing unit .

[0087] The pressure applied to the powder P is calculated from the measurement result of the load sensor 57 and the tip diameter (area) of the cylindrical boss portions 42a, 42b inserted into the receiving hole 31a of the die 30.

[0088] The bulk density is calculated from the volume of the powder P obtained from the displacement of the slider 20 (the thickness of the powder P) and the inner diameter of the containing hole 31a, and the mass of the powder P measured in advance.

[0089] The volume resistivity is calculated from the volume of the powder P and the impedance measured in the impedance measurement step. The electrical conductivity can be obtained as the reciprocal of the volume resistivity.

[0090] In this manner, it is possible to obtain the volume resistivity (conductivity) relative to the pressing pressure and bulk density of the powder P in the frequency swept frequency band. By using the obtained volume resistivity (conductivity) relative to the pressing pressure and bulk density, it is possible to perform characteristic evaluation of the powder P.

[0091] As described above, the measurement method of this embodiment performs AC impedance measurement while compressing the powder P under a high load. Therefore, it is useful for measuring the electrical characteristics of the powder P, which takes into account the capacitance component in the characteristic evaluation. In addition, since the powder P is compressed under a high load, the contact resistance between the electrode parts 40a, 40b and the powder P can be reduced, and the measurement accuracy of the impedance of the powder P itself can be improved. In addition, for the powder P used in a product with a high molding pressure, the electrical characteristics can be measured while applying a pressure equivalent to the actual molding pressure, and characteristic evaluation can be performed in a more commercialized state. Since the characteristics of the solid electrolyte of the all-solid-state battery are evaluated by AC impedance measurement and the powder P is molded under a relatively high load pressure, the measurement device 100 and the measurement method of this embodiment are particularly useful for measuring the electrical characteristics of the solid electrolyte of the all-solid-state battery.

[0092] The above calculation process may be performed each time the measurement results of the displacement sensor 55 and the load sensor 57 are input to the processing unit 70 during the compression process, or may be performed for each measurement result of the displacement sensor 55 and the load sensor 57 stored after the compression process and the impedance measurement process are completed.

[0093] In the calculation step, it is also possible to calculate the volume resistivity at the true density of the powder P based on the relationship between the bulk density and the volume resistivity. Hereinafter, the acquisition of the volume resistivity at the true density will be described.

[0094] To obtain the volume resistivity at the true density, the volume resistivity at the true density can be obtained by substituting the true density into the value of the bulk density in the approximate formula from the graph of the volume resistivity against the bulk density as shown in FIG. 9 obtained by the calculation step. The true density of the powder P can be a value measured by a true density meter, a literature value, a theoretical value, etc., and is stored in the processing unit 70 in advance. That is, in the example shown in FIG. 9, the calculation result of the calculation step is plotted with the horizontal axis being the bulk density and the vertical axis being the volume resistivity, an approximation curve extrapolating the plot is obtained, and the value on the approximation curve when the horizontal axis is the value of the true density can be calculated as the volume resistivity at the true density. Such a volume resistivity at the true density can also be used for the characteristic evaluation of the powder P.

[0095] Next, a modification of this embodiment will be described with reference to FIG.

[0096] The measuring device 100 according to the modified example further includes a temperature adjusting unit 80 that is attached to the die 30 and adjusts the temperature of the powder P in the receiving hole 31a.

[0097] The temperature adjustment unit 80 may have any configuration as long as it can adjust the temperature of the powder P in the receiving hole 31a through the die 30. For example, as shown in FIG. 9, the temperature adjustment unit 80 has a liquid passage 81 provided inside the die 30 to guide the liquid, a pump 82 to circulate the liquid in the liquid passage 81, an adjustment unit 83 to adjust the temperature of the liquid circulating through the liquid passage 81, and a temperature sensor 84 as a temperature measurement unit for measuring the temperature of the powder P. The temperature sensor 84 is, for example, a thermocouple attached to the pair of electrode parts 40a, 40b. The temperature sensor 84 may be provided inside the die 30. By measuring the temperature of the pair of electrode parts 40a, 40b with the temperature sensor 84, the temperature of the powder P in contact with the pair of electrode parts 40a, 40b can be obtained. In addition, as another embodiment, the temperature adjustment unit 80 may be a heater provided inside the die 30.

[0098] By measuring the electrical characteristics of the powder P while adjusting the temperature of the powder P by such a temperature adjustment unit 80, it is possible to evaluate the characteristics of the powder P with respect to temperature.

[0099] When providing such a temperature adjustment unit 80 in the die 30, it is also effective to form the inner part of the inner die 31 of the die 30, which is in contact with the powder P, from an insulator, and to form the part that is not in contact with the powder P from a material with high thermal conductivity such as metal. Furthermore, for example, aluminum nitride is excellent in hardness and insulation as well as thermal conductivity, and is therefore suitable as a material for the die 30 when the temperature adjustment unit 80 is provided.

[0100] Next, other modifications will be described.

[0101] In the above embodiment, the measurement unit 60 applies an AC signal to the electrodes 40a, 40b and performs AC impedance measurement by four-terminal measurement. In contrast, the measurement device 100 has a two-electrode structure in which a pair of application wirings 71a, 71b and measurement wirings 72a, 72b are connected to one electrode 40a, 40b. Therefore, the measurement device 100 can also be used to measure DC resistance by applying a DC signal to the electrodes 40a, 40b. Therefore, for example, the press device 10 can be used in common for measuring DC resistance and impedance by using a measurement unit 60 capable of applying both DC and AC signals, or by preparing a measurement unit 60 that applies a DC signal and a measurement unit 60 that applies an AC signal and switching the connection between them.

[0102] The effects of this embodiment will be described below.

[0103] A measuring device 100 for measuring the electrical characteristics of powder P includes a die 30 having a storage hole 31a for storing the powder P, a pair of electrode sections 40a, 40b that are inserted into the storage hole 31a and sandwich the powder P, a pressure section 50 that applies a high load pressure to the pair of electrode sections 40a, 40b to compress the powder P, and a measuring section 60 that applies an AC signal to the pair of electrodes to measure the impedance of the powder P.

[0104] A measurement method for measuring the electrical characteristics of powder P using the measuring device 100 includes the steps of accommodating the powder P in a storage hole 31a provided in a die 30 in which the powder P is accommodated, compressing the powder P by applying a high load pressure to a pair of electrode portions 40a, 40b that sandwich the powder P, and measuring the impedance of the powder P by applying an AC signal to the pair of electrode portions 40a, 40b.

[0105] According to this embodiment, an AC signal is applied to the powder P to measure the impedance, so that it is possible to perform characteristic evaluation taking into consideration the capacitive component of the powder P. In addition, because a high load pressure is applied to the powder P, it is possible to measure the electrical characteristics of the powder P in a state that matches the actual product state even for the powder P that is molded under high pressure as a product. Therefore, it is possible to appropriately perform characteristic evaluation of various powders P.

[0106] In addition, in the measuring device 100 and the measuring method, each of the pair of electrode portions 40a, 40b has a plate-shaped flange portion 41a, 41b having a cross-sectional area larger than the cross-sectional area of ​​the accommodating hole 31a, and a boss portion 42a, 42b protruding from the flange portion 41a, 41b and inserted into the accommodating hole 31a.

[0107] In such a measuring device 100 and measuring method, the pressure force from the pressure applying section 50 can be received by the flange sections 41a, 41b, which have a relatively large pressure receiving area, and therefore the durability of the electrode sections 40a, 40b can be improved compared to when the flange sections 41a, 41b are not provided.

[0108] The measuring device 100 further includes a table 3a on which the electrode portion 40a is attached, a slider 20 on which the electrode portion 40b is attached and which moves relative to the table 3a, and mounting portions 45a, 45b formed of an insulator for mounting the pair of electrode portions 40a, 40b to the table 3a or the slider 20.

[0109] According to the measuring device 100, the electrodes 40a, 40b can be reliably insulated from the tables 3a, 3b and the slider 20.

[0110] Furthermore, in the measuring apparatus 100, the die 30 is made of an insulating ceramic material.

[0111] According to such a measuring device 100, since the die 30 is made of a highly durable ceramic material, it is possible to apply a higher pressure to the powder P and measure the electrical characteristics of the powder P.

[0112] Moreover, in the measuring device 100, the pressurizing unit 50 is configured to be able to apply to the powder P a pressure of 750 MPa or more.

[0113] With such a measuring device 100, in a product in which the powder P is molded under high molding pressure, it is possible to measure the electrical characteristics of the powder P in accordance with the state in which it is used as a product.

[0114] In addition, in the measurement device 100, each of the pair of electrode portions 40a, 40b is connected to application wiring 71a, 71b that guides electrical signals to be applied to the electrode portions 40a, 40b, and measurement wiring 72a, 72b that guides response signals from the electrode portions 40a, 40b.

[0115] Such a measuring device 100 has a two-electrode structure in which four electrical wirings are connected to two electrodes, and therefore can be used for AC impedance measurement by four-terminal measurement (four-terminal method, four-terminal pair method) in which an AC signal is applied to the electrode portions 40a, 40b, and can also be used for DC resistance measurement by four-terminal measurement in which a DC signal is applied to the electrode portions 40a, 40b.

[0116] In addition, the measuring device 100 further includes a temperature adjusting section 80 that is provided in the die 30 and adjusts the temperature of the powder P.

[0117] According to such a measuring device 100, the characteristics of the powder P with respect to the temperature can be evaluated.

[0118] The measuring device 100 further includes a displacement sensor 55 as a displacement measuring unit that measures the relative displacement of the pair of electrode parts 40a, 40b, and a processing unit 70 that acquires the volume resistivity of the powder P from the volume of the powder P acquired from the relative displacement of the pair of electrode parts 40a, 40b and the measured impedance. The processing unit 70 acquires as a first measurement result the relative displacement of the pair of electrode parts 40a, 40b when a predetermined first load F1 is applied in a state in which the pair of electrode parts 40a, 40b are in direct contact with each other without sandwiching the powder P, and acquires as a second measurement result the relative displacement of the pair of electrode parts 40a, 40b when a second load F2 larger than the first load F1 is applied in a state in which the pair of electrode parts 40a, 40b are in direct contact with each other without sandwiching the powder P. Furthermore, the processing unit 70 obtains the relationship between the load applied to the pair of electrode portions 40a, 40b and the deformation amount of the measuring device 100 based on the first measurement result and the second measurement result, and obtains the volume of the powder based on the thickness of the powder P obtained by subtracting the deformation amount of the measuring device 100 when the load is applied from the measurement result of the displacement sensor 55.

[0119] The measurement method of this embodiment further includes a step of correcting a displacement sensor 55 that measures the displacement of the pair of electrode portions 40a, 40b, and a step of acquiring the volume resistivity of the powder P from the volume of the powder P acquired from the relative displacement of the pair of electrode portions 40a, 40b and the measured impedance. In the step of correcting the displacement sensor 55, the relative displacement of the pair of electrode portions 40a, 40b when a predetermined first load F1 is applied in a state in which the pair of electrode portions 40a, 40b are in direct contact with each other without sandwiching the powder P is acquired as a first measurement result, and the volume resistivity of the powder P when the pair of electrode portions 40a, 40b are in direct contact with each other without sandwiching the powder P is acquired as a first measurement result. A relative displacement of the pair of electrode portions 40a, 40b when a second load F2 larger than the first load F1 is applied with the pair of electrode portions 40a, 40b in direct contact with each other without applying the load F1 is obtained as a second measurement result, and a relationship between the load applied to the pair of electrode portions 40a, 40b and the deformation amount of the measuring device 100 is obtained based on the first measurement result and the second measurement result. In a process of obtaining the volume resistivity, the volume of the powder P is obtained based on the thickness of the powder P obtained by subtracting the deformation amount of the measuring device 100 when the load is applied from the measurement result of the displacement sensor 55.

[0120] According to such a measuring device 100 and measuring method, the thickness of the powder P can be obtained more accurately, and therefore the volume resistivity can be obtained with higher accuracy.

[0121] The measuring device 100 further includes a displacement sensor 55 that measures the relative displacement of the pair of electrode parts 40a, 40b, and a processing unit 70 that acquires the measurement results of the displacement sensor 55 and controls the operation of the measuring unit 60, and the processing unit 70 transmits a signal to the measuring unit 60 to start measuring the impedance by frequency sweeping when the amount of change per unit time of the relative displacement of the pair of electrode parts 40a, 40b compressing the powder P becomes equal to or less than a predetermined threshold. As a result, the measuring unit 60 starts measuring the impedance by frequency sweeping when the amount of change per unit time of the relative displacement of the pair of electrode parts 40a, 40b compressing the powder P by the pressurizing unit 50 becomes equal to or less than a predetermined threshold.

[0122] In addition, in the measurement method of this embodiment, in the process of compressing the powder P, the displacement sensor 55 measures the relative displacement of the pair of electrode portions 40a, 40b compressing the powder P, and in the measurement to measure the impedance, when the amount of change per unit time of the relative displacement of the pair of electrode portions 40a, 40b compressing the powder P becomes equal to or less than a predetermined set value, measurement of the impedance by frequency sweeping is started.

[0123] According to such a measurement method, measurement is not performed when gas is contained in the powder P, and it is possible to suppress the occurrence of wasted time waiting for measurement. Therefore, the impedance measurement of the powder P can be performed accurately and efficiently.

[0124] The measuring device 100 further includes a processing unit 70 that sequentially acquires the measurement results of the measuring unit 60 as preliminary results before starting impedance measurement, and controls the operation of the measuring unit 60. Then, when the amount of change per unit time of the preliminary results of the measuring unit 60 becomes equal to or less than a predetermined threshold, the processing unit 70 transmits a signal to the measuring unit 60 to start impedance measurement.

[0125] Furthermore, in the step of measuring impedance, the measurement method of this embodiment starts measuring the impedance when the amount of change in impedance per unit time becomes equal to or less than a predetermined threshold value.

[0126] According to such a measurement device 100 and measurement method, it becomes possible to start the impedance measurement process by frequency sweeping or start measuring the impedance at the next frequency when the change in impedance has become sufficiently small.

[0127] As a result, for example, in the case where the impedance measurement of the powder P is completed while sweeping the frequency in one minute, the impedance measurement is performed in a state where the impedance change is suppressed every time the frequency of the AC signal is changed, so that it is possible to improve the measurement accuracy while suppressing the lengthening of the measurement time. In this way, the impedance of the powder P can be obtained more accurately, and therefore the volume resistivity can be obtained more accurately.

[0128] The measuring device 100 further includes a processing unit 70 that stores correction information indicating a relationship between the distance between the pair of electrodes 40a, 40b and a correction value for open correction of the pair of electrodes 40a, 40b. When the impedance of the powder P is measured by the measuring unit 60, the processing unit 70 refers to the correction information, acquires a correction value corresponding to the distance between the pair of electrodes 40a, 40b acquired by the displacement sensor 55, and corrects the measurement result of the impedance of the powder P using the acquired correction value.

[0129] According to such a measuring device, the processing unit 70 can obtain a correction value for each interval between the pair of electrode units 40a, 40b by referring to the correction information, and therefore can perform open correction suitable for the thickness of the powder P at the time of measuring the impedance on the measurement result of the impedance of the powder P. Therefore, resistance components such as the wiring resistance between the processing unit 70 and the electrode units 40a, 40b and the contact resistance between the electrode units 40a, 40b and the powder P are removed from the measurement result, and therefore the impedance of the powder P can be measured with high accuracy.

[0130] Furthermore, in the measuring device 100 of this embodiment, the measuring unit 60 measures the impedance in an open state where the pair of electrode units 40a, 40b are open, every time the spacing between the pair of electrode units 40a, 40b is changed by the pressurizing unit 50 without sandwiching the powder P. Then, the processing unit 70 generates and stores the above correction information using the measurement results of the impedance in the open state measured by the measuring unit 60 for each spacing between the pair of electrode units 40a, 40b.

[0131] According to the measurement device 100, the distance between the pair of electrode parts 40a, 40b can be finely adjusted by the pressure unit 50, and the amount of information of the correction value can be increased as necessary, so that the correction information can be generated with high accuracy. In addition, since the measurement information is generated based on the actual measurement values ​​obtained by driving the pressure unit 50 and the measurement unit 60, the accuracy of the open correction can be improved compared to the correction information obtained by simulation, test, or the like.

[0132] In addition, the measurement method of this embodiment further includes a step of measuring the relative displacement of a pair of electrode portions 40a, 40b that compress the powder P using a displacement sensor 55, and measuring the volume of the powder P from the thickness of the powder P and the inner diameter of the storage hole 31a obtained based on the relative displacement, and a step of acquiring the volume resistivity of the powder P from the volume of the powder P and the measured impedance.In the step of acquiring the volume resistivity, the relationship between the bulk density and the volume resistivity of the powder P is acquired based on the mass of the powder P that is determined in advance, and the volume resistivity at the true density is acquired from the relationship between the bulk density and the volume resistivity and the true density of the powder P that is determined in advance.

[0133] According to such a measurement method, the characteristics of the powder P can be evaluated taking into account the volume resistivity at the true density of the powder P.

[0134] Although the embodiments of the present invention have been described above, the above-mentioned embodiments merely show some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above-mentioned embodiments. [Explanation of symbols]

[0135] 100 Measuring Equipment 3a Table 20 Slider 30 Die 31a Receiving hole 40a Electrode section 40b Electrode section 41a Flange part 41b Flange part 42a Boss part 42b Boss part 45a Mounting part 45b Mounting part 50 Pressurizing section 55 Displacement sensor (displacement measurement part) 57 Load sensor (load measurement section) 60 Measuring part 70 Processing section 71a Power supply wiring 71b Power supply wiring 72a Measurement wiring 72b Measurement wiring 80 Temperature adjustment section F1 First load F2 Second load P powder

Claims

1. A measuring device for measuring electrical properties of a powder, comprising: a die having a receiving hole for receiving the powder; A pair of electrode portions that are inserted into the containing holes and sandwich the powder therebetween; a pressure applying unit that applies a high load pressure to the pair of electrodes to compress the powder; a measurement unit that applies an AC signal to the pair of electrodes to measure the impedance of the powder, Each of the pair of electrode portions is a plate-shaped flange portion having a cross-sectional area larger than a cross-sectional area of ​​the receiving hole; a boss portion protruding from the flange portion and inserted into the receiving hole, Measuring equipment.

2. 2. The measuring device according to claim 1, a table on which one of the pair of electrode units is attached; a slider to which the other of the pair of electrodes is attached and which moves relatively with respect to the table; and a mounting portion formed of an insulator for mounting the pair of electrodes to the table or the slider. Measuring equipment.

3. 2. The measuring device according to claim 1, An application wiring for guiding an electrical signal to be applied to the electrode portion and a measurement wiring for guiding a response signal from the electrode portion are connected to each of the pair of electrode portions. Measuring equipment.

4. 2. The measuring device according to claim 1, The die further includes a temperature adjusting unit for adjusting the temperature of the powder. Measuring equipment.

5. 2. The measuring device according to claim 1, a displacement measuring unit for measuring a relative displacement of the pair of electrodes; A processing unit that acquires the measurement result of the displacement measurement unit and controls the operation of the measurement unit, the processing unit transmits a signal to the measurement unit to start measuring the impedance by frequency sweeping when a change amount per unit time of a relative displacement of the pair of electrode parts compressing the powder becomes equal to or less than a predetermined threshold value. Measuring equipment.

6. 2. The measuring device according to claim 1, a displacement measuring unit for measuring a relative displacement of the pair of electrodes; a processing unit that acquires a volume resistivity of the powder from the volume of the powder acquired from the relative displacement of the pair of electrode units and the measured impedance, The processing unit includes: a first measurement result is obtained by applying a predetermined first load to the pair of electrode portions in a state where the pair of electrode portions are in direct contact with each other without sandwiching the powder therebetween; a second measurement result is obtained by applying a second load larger than the first load to the pair of electrode portions in a state in which the pair of electrode portions are in direct contact with each other without sandwiching the powder therebetween; obtaining a relationship between a load applied to the pair of electrodes and a deformation amount of the measuring device based on the first measurement result and the second measurement result; and acquiring a volume of the powder based on a thickness of the powder obtained by subtracting the deformation amount of the measuring device when the load is applied from the measurement result of the displacement measuring unit. Measuring equipment.

7. 2. The measuring device according to claim 1, a displacement measuring unit for measuring a relative displacement of the pair of electrodes; a processing unit that acquires a volume resistivity of the powder from a volume of the powder acquired from the relative displacement of the pair of electrode units measured by the displacement measuring unit and the measured impedance, The processing unit includes: obtaining a relationship between the bulk density and the volume resistivity of the powder based on a mass of the powder that is grasped in advance; obtaining a volume resistivity at the true density from the relationship between the bulk density and the volume resistivity and a true density of the powder that is previously determined; Measuring equipment.

8. 2. The measuring device according to claim 1, a displacement measuring unit for measuring a relative displacement of the pair of electrodes; a processing unit that stores correction information indicating a relationship between a distance between the pair of electrode parts and a correction value for open correction of the pair of electrode parts, when the impedance of the powder is measured by the measurement unit, the processing unit refers to the correction information, acquires the correction value corresponding to the interval of the pair of electrode units acquired by the displacement measurement unit, and corrects the measurement result of the impedance of the powder using the acquired correction value. Measuring equipment.

9. The measuring device according to claim 8, the measurement unit measures impedance in an open state in which the pair of electrode units are open every time the spacing between the pair of electrode units is changed by the pressurizing unit; The processing unit generates and stores the correction information by using a measurement result of the impedance in the open state measured by the measurement unit for each interval of the pair of electrode units. Measuring equipment.

10. 2. The measuring device according to claim 1, A processing unit is further provided to sequentially obtain the measurement results of the measurement unit and control the operation of the measurement unit. The processing unit transmits a signal to the measurement unit to start measuring the impedance when a change amount per unit time of the measurement result of the measurement unit becomes equal to or less than a predetermined threshold. Measuring equipment.

11. A method for measuring electrical properties of a powder using a measuring device, comprising the steps of: A step of accommodating the powder in an accommodating hole provided in a die in which the powder is accommodated; a step of applying a high pressure load to a pair of electrodes sandwiching the powder to compress the powder; and applying an AC signal to the pair of electrodes to measure the impedance of the powder. Each of the pair of electrode portions is a plate-shaped flange portion having a cross-sectional area larger than a cross-sectional area of ​​the receiving hole; a boss portion protruding from the flange portion and inserted into the receiving hole, Measurement method.

12. The measurement method according to claim 11, correcting a displacement measuring unit that measures a relative displacement of the pair of electrode units; and acquiring a volume resistivity of the powder from the volume of the powder acquired from the relative displacement of the pair of electrode units and the measured impedance. In the step of correcting the displacement measuring unit, a first measurement result is obtained by applying a predetermined first load to the pair of electrode portions in a state where the pair of electrode portions are in direct contact with each other without sandwiching the powder therebetween; a second measurement result is obtained by applying a second load larger than the first load to the pair of electrode portions in a state in which the pair of electrode portions are in direct contact with each other without sandwiching the powder therebetween; obtaining a relationship between a load applied to the pair of electrodes and a deformation amount of the measuring device based on the first measurement result and the second measurement result; In the step of acquiring the volume resistivity, a volume of the powder is acquired based on a thickness of the powder acquired by subtracting a deformation amount of the measuring device when the load is applied from a measurement result of the displacement measuring unit. Measurement method.

13. The measurement method according to claim 11, In the step of compressing the powder, a displacement measuring unit measures a relative displacement of the pair of electrode units compressing the powder, In the measurement of the impedance, when a change amount per unit time of a relative displacement of the pair of electrodes compressing the powder becomes equal to or less than a predetermined threshold, the measurement of the impedance by frequency sweep is started. Measurement method.

14. The measurement method according to claim 11, In the step of measuring the impedance, measurement of the impedance is started when a change in the impedance per unit time becomes equal to or less than a predetermined threshold. Measurement method.

15. The measurement method according to claim 11, and acquiring a volume resistivity of the powder from the volume of the powder acquired from the relative displacement of the pair of electrode parts measured by a displacement measuring unit and the measured impedance, In the step of acquiring the volume resistivity, obtaining a relationship between the bulk density and the volume resistivity of the powder based on a mass of the powder that is grasped in advance; obtaining a volume resistivity at the true density from the relationship between the bulk density and the volume resistivity and a true density of the powder that is previously determined; Measurement method.

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