Physical property measuring apparatus

Abstract

To accurately measure impedance simultaneously with viscosity measurement even for a sample such as a slurry having low viscosity and low electric resistance.SOLUTION: A material property measuring apparatus 10 includes an upper plate 31, a lower plate 35, a viscosity measuring device 3 configured to measure a viscosity η [Pa·s] of a sample S, and an impedance measuring device 4 configured to measure an impedance of the sample S, wherein a bottom surface of the upper plate 31 in contact with the sample S is made of an insulator, and an upper electrode 41 is disposed in an annular strip-shaped region concentric with a rotation axis of the upper plate so as to be in electrical contact with the sample S at a part of the insulator.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a physical property measuring device, and more particularly to a physical property measuring device that can measure the impedance with high accuracy simultaneously with viscosity measurement even for a slurry with low viscosity and low electrical resistance. [Background technology]

[0002] Conventionally, for example, to measure the physical properties of electrode slurry to be applied to the electrodes of lithium-ion secondary batteries, the viscosity η [Pa·s] was measured using a rheometer, and the electrical properties were obtained by impedance measurement.

[0003] However, measurements of viscosity η [Pa s] and impedance Z [Ω] vary depending on the temperature [°C] of the object being measured, shear rate D [1 / s], etc. For this reason, if viscosity η [Pa s] or impedance is measured at different locations or times, the measurement conditions will be different, which can lead to the problem of inaccurate measurements.

[0004] Therefore, a physical property measuring device such as that described in Patent Document 1 has a first plate that can rotate and vibrate and a second plate that is positioned opposite the first plate and has an impedance measurement unit. A sample is placed between the first and second plates, and stress is measured in response to strain applied to the sample by rotating the first plate. In addition, a physical property measuring device has been proposed that uses the first and second plates as electrodes to measure the impedance of the sample in the impedance measurement unit. With such a physical property measuring device, it is possible to simultaneously measure the viscosity η [Pa s] and impedance Z [Ω] of the same sample. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-288049 Summary of the Invention [Problem to be solved by the invention]

[0006] However, for example, the electrode slurry used to coat the electrodes of lithium-ion secondary batteries has low electrical resistance due to the conductive additives and low viscosity η [Pa·s] to enable coating. Therefore, if the gap between the opposing plates is too narrow, the electrical resistance is too low for impedance measurement. On the other hand, if the gap is too wide, there is a contradictory problem that the sample cannot be maintained because it is scattered by the rotation of the plates.

[0007] The problem to be solved by the physical property measuring device of the present invention is to measure the impedance with high accuracy at the same time as measuring the viscosity, even for a sample such as a slurry that has low viscosity and low electrical resistance. [Means for solving the problem]

[0008] In order to solve the above problems, the physical property measuring device of the present invention includes a measuring section in which an upper measuring section and a lower measuring section are arranged below the upper measuring section so as to face each other and are rotatably driven relative to each other; a viscosity measuring device that calculates shear stress τ [Pa] from the cross-sectional area of ​​a sample sandwiched between the upper measuring section and the lower measuring section, and shear rate [1 / s] from the radius of the sample and the gap between the upper measuring section and the lower measuring section, based on the torque and rotation speed when the upper measuring section and the lower measuring section rotate relative to each other, and measures viscosity η [Pa s] of the sample; and an impedance measuring device that measures the impedance of the sample using the upper electrode and the lower electrode, wherein the surface of at least one of the upper measuring part and the lower measuring part that contacts the sample is made of an insulator, and at least one of the upper electrode of the upper measuring part and the lower electrode of the lower measuring part is arranged in at least a part of an annular band-shaped area concentric with the center of rotation of the measuring part so as to be in electrical contact with the sample at a part of the insulator.

[0009] At least one of the upper measuring part and the lower measuring part may have a flat, disk-shaped opposing surface, or at least one of the upper measuring part and the lower measuring part may have a conical opposing surface, but is not limited thereto.

[0010] The electrode may be an annular electrode arranged in an annular region concentric with the center of rotation of the measuring unit, or the upper electrode may be one or more circular electrodes arranged in a part of the annular region concentric with the center of rotation of the measuring unit.

[0011] At least one of the upper measuring portion and the lower measuring portion may have an inner insulator region and an outer insulator region, and the upper electrode may be disposed between the inner insulator region and the outer insulator region.

[0012] The radial width of the upper electrode is preferably 1% or more and 50% or less of the diameter of the measuring portion. At least one of the upper measuring part and the lower measuring part may be made of a conductor, and the entire lower measuring part may be configured as the lower electrode.

[0013] It is also preferable that the upper measuring portion and the lower measuring portion are formed by the insulator, and that the lower electrode is circumferentially disposed on a part of the insulator so as to face the upper electrode. The present invention can be suitably carried out particularly when the sample is an electrode slurry, and further when the electrode slurry is an electrode slurry containing a conductive additive for a positive electrode of a lithium ion secondary battery. [Effects of the Invention]

[0014] According to the physical property measuring device of the present invention, it is possible to measure the impedance with high accuracy simultaneously with the viscosity measurement even for a sample such as a slurry having low viscosity and low electrical resistance. [Brief explanation of the drawings]

[0015] [Figure 1]FIG. 1 is a schematic diagram showing an example of the configuration of a physical property measuring device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view taken along the center of rotation, showing the configuration of an upper plate and a lower plate. [Figure 3] FIG. [Figure 4] 4 is a cross-sectional view of the upper plate taken along the center of rotation of the portion IV-IV of FIG. 3. [Figure 5] FIG. [Figure 6] 6 is a cross-sectional view of the lower plate taken along the center of rotation of the portion VI-VI in FIG. 5. [Figure 7] 1 is a table summarizing the advantages and disadvantages of wide and narrow gaps G between plates in a physical property measuring device according to the prior art. [Figure 8] 10 is a graph showing changes in the Nyquist plot depending on the width of the gap G [mm]. [Figure 9] 10 is a Nyquist plot showing impedance measurements using the conventional technique and the upper electrode 41 of this embodiment at a shear rate of D=0 [1 / s], i.e., in a stationary state. [Figure 10] 10 is a Nyquist plot showing impedance measurements using the upper electrode of the conventional technology and the present embodiment when rotating at a shear rate of D=1000 [1 / s], i.e., at high speed. [Figure 11] FIG. 10 is a cross-sectional view taken along the center of rotation of a modified example of the upper plate. [Figure 12] FIG. 10 is a cross-sectional view taken along the center of rotation of a modified example of the lower plate. [Figure 13] FIG. 10 is a plan view of a modified example of the lower plate. [Figure 14] FIG. 10 is a bottom view of another modified example of the upper plate. [Figure 15] FIG. 10 is a bottom view of yet another modified example of the upper plate. [Figure 16] FIG. 1 is a schematic diagram showing the configuration of an upper plate and a lower plate of a conventional physical property measuring device. [Figure 17]1 is a schematic diagram showing the difference in velocity V [mm / s] depending on the position from the center of rotation O when viewing an upper plate of the conventional technology from below. [Figure 18] FIG. 1 is a diagram showing the relationship between the shear rate D [1 / s] of a sample S in a viscosity measurement device of a physical property measurement device according to the prior art. [Figure 19] FIG. 2 is a diagram schematically illustrating the uniformity of the positive electrode active material and the conductive additive in the electrode slurry, and the state of the degree of network development. [Figure 20] 1 is a Nyquist plot showing properly measured impedance of an electrode slurry. [Figure 21] 1 is a Nyquist plot comparing the impedance of electrode slurries containing different amounts of conductive additive SE. DETAILED DESCRIPTION OF THE INVENTION

[0016] (Outline of this embodiment) <Problems with the prior art> First, the problems of the prior art of the present invention described in the background art will be supplemented with a description of the technical premise.

[0017] <Measurement using conventional physical property measuring equipment> FIG. 16 is a schematic diagram showing the configuration of an upper plate 131 and a lower plate 135 of a viscosity measuring device 103, a physical property measuring device of the prior art. In the physical property measuring device described in Patent Document 1 mentioned in the background art, as shown in FIG. 16, an electrode slurry serving as a sample S is placed on a lower plate 135 having a flat upper surface. A disk-shaped upper plate 131 having a flat lower surface is brought into close contact with the sample S from above, with a predetermined gap G formed between them. The upper plate 131 rotates around a rotation center O by a rotation shaft 32. The upper plate 131 and the lower plate 135 of the prior art are entirely made of a conductor made of steel such as stainless steel or Al.

[0018] FIG. 17 is a schematic diagram showing the difference in velocity V [mm / s] at different positions of radius r from the center of rotation O when viewing an upper plate 131 of the prior art from below. The upper surface of the sample S, which is in close contact with the lower surface of the upper plate 131, moves in the rotation direction together with the upper plate 131 due to the rotation shaft 132 rotating at an angular velocity ω around the rotation center O. At this time, the lower surface of the sample S, which is in close contact with the lower plate 135, is basically fixed by the lower plate 135 and does not move.

[0019] FIG. 18 shows the relationship between the shear rate D [1 / s] of the sample S in the viscosity measurement device 103, a conventional physical property measurement device. The shear rate D [1 / s] is determined by the difference in relative velocity V [mm / s] between the upper plate 131 and the lower plate 135 and the gap G between them. In FIG. 17, the velocity V [mm / s] is proportional to the length of each dotted line. Here, when the shear stress τ [Pa], the viscosity η [Pa·s], the shear rate D [1 / s], and the gap G [mm] are taken as the shear stress, τ = η(V / G) = η·D. In a rotational viscometer, the upper plate 131 and the lower plate 135 move relative to each other, but this is a rotational movement rather than a parallel movement. That is, as shown in FIG. 17, the velocity V in the region close to the center of rotation O, i.e., the region of radius r1 where the radius r is small, is r1 [mm / s] is the velocity V in the area of ​​radius r4 where radius r is large. r4 The shear rate D [1 / s] is proportional to the velocity V [mm / s] when the gap G [mm] is constant. Therefore, the shear rate D [1 / s] increases toward the outer periphery of the upper plate 131. In other words, the torque M [N·m] resulting from the shear stress τ [Pa] applied to the rotating shaft 32 is generated by the composite shear rate D [1 / s] at each position on the upper plate 131. Based on the torque M [N·m] when the upper plate 131 rotates, the shear stress τ [Pa] is calculated from the cross-sectional area of ​​the sample S sandwiched between the upper plate 131 and the lower plate 135, and the viscosity η [Pa·s] of the sample S is measured. However, in the viscosity measurement device 3 of this embodiment, the relationship between the viscosity η [Pa·s] and the torque M [N·m] can actually be experimentally derived, and using this relationship does not pose a measurement problem.

[0020] <Measurement using conventional impedance measuring device 104> Next, a description will be given of measurements using the conventional impedance measuring device 104. The impedance measuring device 4 of this embodiment and the conventional impedance measuring device 104 have the same configuration except for the upper electrode 41 and the lower electrode 42. Prior to this description, a brief description will be given of impedance measurements and Nyquist plots that represent the results.

[0021] FIG. 19 shows the positive electrode active material S in the electrode slurry. A and conductive additive S E 10 is a diagram showing a schematic diagram for comparing the uniformity of the network and the state of network development. As shown in FIG. 19, the electrode slurry of sample S contains positive electrode active material S. A and conductive additive S E and organic solvent S S As an example of this embodiment, the positive electrode active material S A The conductive additive S is made of particles of a so-called ternary lithium transition metal oxide containing Ni, Co, and Mn. E Carbon nanotubes are used as the binder, and polyvinylidene fluoride (PVdF) is used as the binder. S N-methyl-2-pyrrolidone (NMP) is used as the solvent.

[0022] The diagram at the bottom left of Figure 19 shows the organic solvent S in a state where the network is not uniform and has not yet developed. S Positive electrode active material S A and conductive additive S E The figure shows the state in which the binder is added. In this case, the positive electrode active material S is made of particles of a ternary lithium transition metal oxide. A and conductive additive S made of carbon nanotubes E Since both of these materials tend to aggregate, simply mixing the powders together will not produce a uniform positive electrode active material S. A and conductive additive S E In the upper left figure, for example, the organic solvent S S Conductive additive S dispersed in E and positive electrode active material SA When these are mixed, the organic solvent S S Among them, the positive electrode active material S A and conductive additive S E This indicates a dispersed state. The network is highly uniform, but the degree of development is low. Therefore, the conductive additive S E is in a dispersed state, but the conductive additive S E Therefore, the positive electrode active material S A Between them, the organic solvent S, which is an insulator, S functions as a capacitor having a capacitance.

[0023] Furthermore, by kneading these under specified conditions, a state in which a network and aggregates are mixed is created, as shown in the lower right. As a result, the network in which carbon nanotubes are linked in a chain shape is not uniform, but in some areas the network is highly developed. In this case, sample S is mixed with organic solvent S. S The capacitor and the conductive additive S E This results in a combined resistance with the resistor.

[0024] Then, when the network is highly uniform and well developed as shown in the upper right corner by proper kneading, the positive electrode active material S is formed, in which chained carbon nanotubes are dispersed. A Then, the positive electrode active material S A is the conductive additive S E A network structure is constructed, and this conductive network reduces the DC resistance DC-R.

[0025] Therefore, the mixed positive electrode slurry, which is sample S, can be regarded as a CR circuit as an electrical equivalent circuit. Therefore, its state can be measured by performing complex impedance measurements on the resistance component and capacitance component.

[0026] Figure 20 is a Nyquist plot showing the impedance Z [Ω] of properly measured electrode slurry. The horizontal axis of the graph is the real axis, and R SThe vertical axis is an imaginary axis, representing -X [Ohm]. For the measurement, for example, an LCR meter IM3536 manufactured by Hioki E.E. Corporation can be used. A voltage [V] or current [A] is applied to the sample S from the impedance measuring device 104 so as to sweep the voltage or current, continuously changing from high frequency to low frequency.

[0027] When the impedance Z [Ω] is measured properly, the positive electrode active material S contained in the electrode slurry A , Conductive additive S E , binder, organic solvent S S Since the capacitance component at the interface between each material changes depending on the state of each material, multiple arcs corresponding to each component are observed. As the amount of material increases, the arcs become smaller. Furthermore, the size of the arcs can be used to estimate the degree of mixing of the conductive materials in terms of electronic conductivity.

[0028] Figure 21 shows the conductive additive S E This is a Nyquist plot comparing the impedance Z [Ω] of electrode slurries with different amounts of R added. The horizontal axis of the graph is the real axis, and S The vertical axis is the imaginary axis, and represents -X [Ohm]. As shown in Figure 21, the conductive additive S E When the amount of conductive additive S is different, E This type of analysis is possible because the arc portion corresponding to

[0029] It should be noted here that the state of a sample changes not only with its composition but also with the temperature (°C) of the sample being measured and the shear rate (D) (1 / s), so viscosity (η) (Pa·s) and impedance (Z) (Ω) must be measured at the same shear rate (D) (1 / s).

[0030] However, in the impedance measurement using the conventional impedance measuring device 104, the impedance was measured using the entire first plate and second plate as electrodes. Therefore, the measurement results include a composite of results at different shear rates D [1 / s]. This posed a problem in that it was not possible to accurately evaluate the electrode slurry.

[0031] <Gap G [mm] setting> 8 is a graph showing the change in the Nyquist plot depending on the gap G [mm]. When the gap G is sufficient (for example, 2 [mm] or more), the positive electrode active material S A and conductive additive S E On the other hand, when the gap G is too narrow (for example, less than 0.1 mm), the resistance of sample S drops significantly in graph L2, that is, the entire graph is compressed to the left, and the positive electrode active material S A and conductive additive S E The arc portion showing the impedance is not clear, making impedance analysis difficult.

[0032] As described above, when the gap G is narrow (for example, less than 0.1 mm), if the sample S has low resistance such as electrode slurry, it is found that there is a problem that impedance measurement may become difficult.

[0033] On the other hand, depending on the viscosity η [Pa·s] of the sample S, widening the gap G [mm] (e.g., 2 mm or more) can cause the following problems. For example, if the sample S is an electrode slurry, a low viscosity η [Pa·s] is required for coating. In such a case, if the gap G is set large for the reasons described above, the rotation of the rotating shaft 32 must be performed at a higher angular velocity ω proportional to the gap G, compared to when the gap G is narrow, in order to measure at the same shear rate D [1 / s]. In other words, a higher angular velocity ω is required for measurement. For example, if the sample S is an electrode slurry with a low viscosity η [Pa·s], a large gap G [mm] makes it difficult to hold the sample S between the upper plate 31 and the lower plate 35. Furthermore, if the sample S is rotated at a high speed, the large centrifugal force generated by the high speed rotation can prevent the sample S from being held between the upper plate 31 and the lower plate 35, resulting in the sample S scattering.

[0034] 7 is a table summarizing the advantages and disadvantages of widening or narrowing the gap G between the plates in the conventional physical property measuring device described above. As can be seen from the comparison in this table, there are disadvantages both when the gap G is wide and when it is narrow, so in the conventional physical property measuring device 110, the widening or narrowing of the gap G posed a trade-off that could not be resolved.

[0035] To address this issue, it is possible to increase the electrical resistance [Ω] of the sample S between the electrodes by reducing the area of ​​the electrodes and the cross-sectional area [mm2] of the sample S between the electrodes. However, simply reducing the cross-sectional area [mm2] of the sample S between the electrodes leads to the following problems:

[0036] <Setting the shear rate D [1 / s]> In the impedance measuring device 4, the impedance Z [Ω] changes depending on the shear rate D [1 / s], which will be explained below.

[0037] FIG. 9 is a Nyquist plot showing impedance measurements at a shear rate D=0 [1 / s], i.e., in a stationary state, using the conventional technology and the upper electrode 41 of this embodiment. Here, graph L3 is a Nyquist plot showing the results of impedance measurements using the upper plate 31 configured with the upper electrode 41 of this embodiment. Graph L4 is a Nyquist plot showing the results of impedance measurements using the conventional technology with the entire upper plate 131 as an electrode. As shown in FIG. 9, graph L4 of the impedance measurements using the conventional technology with the entire upper plate 131 as an electrode shows the positive electrode active material S A and conductive additive S E No arc appears, making impedance analysis difficult.

[0038] On the other hand, in the graph L3 of the impedance measurement for the upper plate 31 having the upper electrode 41 of this embodiment, the positive electrode active material S A and conductive additive S E The arc indicating the shear rate D [1 / s] clearly appears, indicating that impedance analysis can be performed appropriately. This shows that the area of ​​the upper electrode 41 is important in measuring the impedance of the sample S, regardless of the shear rate D [1 / s].

[0039] FIG. 10 is a Nyquist plot showing impedance measurements using the upper electrode 41 of the present embodiment and the conventional technology when the average shear rate D is 1000 [1 / s], i.e., when rotated at high speed. Here, graph L5 is a Nyquist plot showing the results of impedance measurements using the configuration of the upper electrode 41 of the present embodiment. Graph L6 is a Nyquist plot showing the results of impedance measurements using the entire upper plate 31 of the conventional technology as an electrode. Graph L6 of the impedance measurements using the entire upper plate 131 of the conventional technology as an electrode shows the results of impedance measurements using the positive electrode active material S A and conductive additive S E It can be seen that the arc indicating the impedance does not appear, making it difficult to analyze the impedance.

[0040] On the other hand, in the graph L5 of the impedance measurement of the upper plate 31 having the upper electrode 41 of this embodiment, the positive electrode active material S A and conductive additive S E The arc representing the shear rate D [1 / s] clearly appears, indicating that impedance analysis can be performed appropriately. In other words, it can be seen that the real component of impedance Rs [Ω] decreases when the shear rate D [1 / s] is high. Therefore, it can be seen that the shear rate D [1 / s] is also an important factor for accurate impedance measurement.

[0041] The reason why the ion migration resistance [Ω] decreases as the shear rate D [1 / s] increases is considered to be as follows. For example, when the conductive additive S is added to the electrode slurry of the positive electrode of the lithium ion secondary battery of this embodiment, E Carbon nanotubes and other conductive additives are mixed in. E When left standing, the conductive additive S aggregates, but when the shear rate D [1 / s] is high, the conductive additive S aggregates. E It is presumed that the ions disperse and form a conductive network in the electrode slurry, which is thought to reduce the ion migration resistance Rct [Ω].

[0042] When parallel plates are used, the shear rate D [1 / s] at the center is zero, and the shear rate D [1 / s] increases in proportion to the radius r from the center of rotation O, as shown in Figure 3. In other words, if the entire parallel plate is treated as an electrode, currents at various shear rates D [1 / s] are applied to the sample.

[0043] However, since the aggregation structure of particles dispersed in the slurry changes depending on the shear rate D [1 / s], measuring the impedance Z [Ω] from the center to the outermost periphery will result in measuring the impedance Z [Ω] of a variety of structural states.

[0044] To address this problem, the physical property measuring device 10 of this embodiment forms the upper electrode 41 and the lower electrode 42 in the shape of a concentric ring or arc. By using the upper electrode 41 and the lower electrode 42 to measure the current in the area where the shear rate D [1 / s] is the same, it becomes possible to measure the impedance only in the area where the shear rate D [1 / s] is the same.

[0045] Furthermore, by forming the electrodes in the shape of concentric rings or arcs, it becomes possible to use cone plates for the upper plate 31 and the lower plate 35. (Configuration of this embodiment) Next, the physical property measuring device 10 of this embodiment for solving such problems will be described in detail. First, the electrode slurry, which is the sample S of this embodiment, will be briefly described.

[0046] <Electrode slurry> The sample S in this embodiment is described as an example of a positive electrode slurry among electrode slurries for a lithium ion secondary battery. Of course, it is not limited to a positive electrode, and it goes without saying that it can also be applied to a negative electrode slurry. Furthermore, the object of the physical property measuring device 10 in this embodiment is not limited to a slurry.

[0047] The electrode slurry for the positive electrode of this embodiment is a positive electrode active material S A In addition to the particles, conductive additive S E , binders and dispersants, and other additives, organic solvents S The positive electrode mixture layer is formed by adjusting the electrode slurry to the appropriate viscosity η [Pa·s] in the coating process and coating it on the positive electrode current collector. It is then dried and fixed in the drying process. At the electrode slurry stage, the organic solvent S S However, the positive electrode mixture layer after the drying process contains the organic solvent S. S It evaporates and disappears.

[0048] <Cathode active material S A Composition of Cathode active material S AThe particles contain a lithium transition metal oxide having a layered crystal structure. The lithium transition metal oxide contains one or more predetermined transition metal elements in addition to Li. The transition metal element contained in the lithium transition metal oxide is preferably at least one of Ni, Co, and Mn. A suitable example of the lithium transition metal oxide is a lithium transition metal oxide containing all of Ni, Co, and Mn.

[0049] The positive electrode active material particles may contain one or more additional elements in addition to a transition metal element (i.e., at least one of Ni, Co, and Mn). The additional elements may include any of elements belonging to Group 1 (alkali metals such as sodium), Group 2 (alkaline earth metals such as magnesium and calcium), Group 4 (transition metals such as titanium and zirconium), Group 6 (transition metals such as chromium and tungsten), Group 8 (transition metals such as iron), Group 13 (metalloid element boron or metals such as aluminum), and Group 17 (halogens such as fluorine) of the periodic table.

[0050] <Binding material> The binder may be, for example, polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), polyacrylic acid, polyacrylate, or the like.

[0051] <Conductive additive S E > Since the binder has a high electrical resistance, it is necessary to increase the conductivity between the positive electrode active material particles. E is a material that forms a conductive path in the positive electrode mixture layer to enhance conductivity. E By mixing the conductive additive S of this embodiment, a conductive network is formed to increase the conductivity inside the positive electrode mixture layer, thereby improving the charge / discharge efficiency and output characteristics of the battery. ECarbon materials such as carbon nanotubes (CNTs) and carbon nanofibers (CNFs) can be used as the electrode material. Furthermore, string-like materials with an aspect ratio of 30 or more are used. Carbon nanotubes (CNTs) and other materials tend to aggregate easily, and are supplied as raw materials dispersed in organic solvents. However, as the aggregation and dispersion state changes during mixing and other processes, the state of the conductive network that is formed also changes. Therefore, when measuring the impedance of electrode slurries, the shear rate D [1 / s] and other factors affect the state, and this must be taken into consideration.

[0052] < Organic Solvents S > The electrode slurry having such a composition can be prepared by dissolving the electrode in an organic solvent such as N-methyl-2-pyrrolidone (NMP). S The viscosity can be adjusted to a desired value (e.g., 0.5 to 20 Pa·s) by the addition of the organic solvent S. S The amount of is determined by the viscosity η [Pa·s] required in the coating process.

[0053] <Physical property measuring device 10> Fig. 1 is a schematic diagram showing an example of the configuration of a physical property measuring device 10 according to this embodiment. It goes without saying that the physical property measuring device 10 is not limited to the example shown. As shown in Fig. 1, the physical property measuring device 10 includes a viscosity measuring device 3 that is supported by a support 1 and can be raised and lowered by a gap adjusting device 2.

[0054] The support 1 includes a housing 13, a stage 11 on which a lower plate 35 is horizontally arranged on the housing 13, and a column 12 that extends vertically upward from the housing 13 and supports the viscosity measuring device 3 so that it can be raised and lowered.

[0055] The gap adjustment device 2 includes a lifting stage 21 that can be raised and lowered relative to the column 12, a spindle 22 that raises and lowers the lifting stage 21 with a screw, a motor 23 that rotates the spindle 22, and an encoder 24 that detects the rotation of the motor 23. The motor 23 is rotated by a control device (not shown) to adjust the gap G. Note that the adjustment of the gap G described here is just one example, and adjustment can be made using, for example, a spindle 22 that is not fixed to the stage 11. Adjustment can also be made using two columns 12. Furthermore, adjustment can also be made by using two motors 23 for the stage 11.

[0056] The viscosity measurement device 3 includes an upper plate 31 that contacts the sample S horizontally from above, a rotating shaft 32 that rotates the upper plate 31, and a measurement motor 33. The measurement motor 33 drives the rotating shaft 32 with a predetermined output and detects the torque M [N m] applied to the rotating shaft 32. In addition, an encoder 34 detects the rotation of the measurement motor 33.

[0057] The lower plate 35 constituting the lower measurement section is placed on the horizontal stage 11 of the support 1. In this embodiment, the lower plate 35 is fixed to the stage 11, but this is not limiting. The upper plate 31 constituting the upper measurement section may not be rotated, and the lower plate 35 may be rotated relative to the upper plate 31. The upper plate 31 and lower plate 35 constituting the measurement section are placed horizontally and parallel to face each other vertically, and a sample S is filled between the upper plate 31 and the lower plate 35.

[0058] An upper electrode 41 is disposed on the upper plate 31, and a lower electrode 42 is disposed on the lower plate 35. The upper electrode 41 and the lower electrode 42 constitute an electrode. The upper electrode 41 is electrically connected to the measuring unit 43 of the impedance measuring device 4. In this embodiment, an insulator 32a is disposed on a part of the rotating shaft 32 to provide electrical insulation from the upper part of the rotating shaft 32. A contact 32b is provided between the insulator 32a and the lower end of the rotating shaft 32, and the contact 32b presses the electrode against the rotating shaft 32, which rotates, using a spring. The upper electrode 41 and the lower end of the rotating shaft 32 are electrically connected and fixed. This configuration ensures electrical continuity with the upper electrode 41, allowing impedance measurement. This configuration blocks electrical noise from the upper part of the rotating shaft 32 as it is driven, and the signal from the upper electrode 41 can be accurately transmitted to the measuring unit 43.

[0059] Alternatively, a rotating disk electrode (not shown) can be used as an alternative connection method. The upper electrode 41 and the lower end of the rotating shaft 32 are electrically fixed and connected. An insulator 32a is provided on a portion of the rotating shaft 32 to electrically insulate it from the upper portion of the rotating shaft 32. A rotating disk electrode 32c is then provided between the insulator 32a and the lower end of the rotating shaft 32. For the rotating disk electrode 32c, a liquid reservoir is formed around the rotating shaft 32, with the insulator tightly attached. This reservoir is filled with an electrolyte solution, such as KCl. A spring-contact contact electrically connected to the measuring unit 43 is provided on the portion of the rotating shaft 32 immersed in the liquid reservoir. This configuration establishes electrical continuity with the upper electrode 41, allowing impedance measurement. This configuration blocks electrical noise from the upper portion of the rotating shaft 32 and suppresses noise generated by dynamic contacts, creating a steady state. This allows signals from the upper electrode 41 to be accurately transmitted to the measuring unit 43.

[0060] The measurement unit 43 of the impedance measurement device 4 includes an application device that can continuously apply a current [A] or a voltage [V] to the sample S from the upper electrode 41 and the lower electrode 42 while changing the frequency [Hz], from high to low frequencies. It also includes a measurement device that measures the resistance [Ω] for the current [A] or voltage [V] applied to the sample S. It also includes an analysis device that analyzes this data and outputs the analysis results as a Nyquist plot. This function allows impedance measurement to be performed by applying a current [A] or a voltage [V] to the sample S while changing the frequency [Hz] using the upper electrode 41 disposed on the upper plate 31 and the lower electrode 42 disposed on the lower plate 35. The measurement unit 43 measures the complex impedance of the sample S from the changes in the current [A] or voltage [V] and outputs a Nyquist plot.

[0061] <Configuration of upper plate 31 and lower plate 35> FIG. 2 is a schematic cross-sectional view taken along the center of rotation O, showing the configuration of the upper plate 31 and the lower plate 35. As shown in FIG.

[0062] FIG. 3 is a bottom view of the upper plate 31. As shown in FIG. 3, the entire upper plate 31 has a circular shape centered on the rotation center O when viewed from the bottom. The diameter φ of the bottom surface 31c is, for example, 50 mm. Furthermore, on this bottom surface 31c, at a radius r3=33.3 / 2 mm, a conductive annular upper electrode 41 made of, for example, Cu is formed in a portion having a width of 1.0 mm in the radial direction centered on the circumference of the radius. An inner insulator region 31a made of, for example, polyacetal resin (POM resin) in this embodiment is formed on the radial inner side of this upper electrode 41. Polyacetal resin (POM resin) has high insulating properties. Furthermore, it has high strength, abrasion resistance, heat resistance, and organic solvent resistance, and is therefore suitable for preventing the sample S from being dissolved in an organic solvent S such as an electrode slurry. S It can also be suitably used in cases where the composition contains

[0063] Similarly, an outer insulator region 31b made of polyacetal resin (POM resin) is formed on the outer side of the upper electrode 41 in the radial direction. The bottom surface 31c is a horizontal flat surface so that the inner insulator region 31a, the upper electrode 41, and the outer insulator region 31b are flush with each other.

[0064] FIG. 4 is a cross-sectional view of the upper plate 31 along the center of rotation O at the IV-IV portion of FIG. 3. The upper plate 31 has an annular outer insulator region 31b at its outermost periphery. The thickness of the outer insulator region 31b in the radial direction r is uniform from top to bottom. The inner periphery of the outer insulator region 31b has a disk-shaped upper electrode 41 with the same thickness in the height direction. The inner insulator region 31a fills a cylindrical recess formed in the lower part of this upper electrode 41. The thickness of the inner insulator region 31a in the height direction is approximately 45% of the thickness of the upper plate 31. The upper surface 31d of the upper plate 31 is a horizontal, flat surface such that the inner insulator region 31a, upper electrode 41, and outer insulator region 31b are flush with each other.

[0065] Furthermore, a connecting portion 31e that connects to the rotating shaft 32 is provided near the center of rotation O on the upper surface 31d of the upper plate 31. Although the detailed configuration of the connecting portion 31e is not shown in the figure, the connecting portion 31e can connect the upper plate 31 to the rotating shaft 32 so that the upper plate 31 can rotate synchronously with the rotating shaft 32, with the rotating shaft 32 and the connecting portion 31 having the common center of rotation O, and can accurately transmit the torque M [N m]. Therefore, upper plates 31 with different configurations can be attached to the rotating shaft 32 by replacing them as desired. Note that the connecting portion 31e is not limited to the example shown, and for example, a recess may be formed on the upper surface 31d of the upper plate 31, into which the lower end of the rotating shaft 32 is fitted or screwed.

[0066] FIG. 5 is a plan view of the lower plate 35. As shown in FIG. 5, the lower plate 35 is formed in a disk shape similar to the upper plate 31 when viewed in plan. FIG. 6 is a cross-sectional view of the lower plate 35 taken along the rotation center O of the portion VI-VI in FIG. 5. As shown in FIG. 6, the lower plate 35 of this embodiment has a configuration obtained by turning the upper plate 31 shown in FIG. 4 upside down. Therefore, as shown in FIG. 2, the upper electrode 41 on the bottom surface 31c of the upper plate 31 and the lower electrode 42 on the top surface 35c of the lower plate 35 appear symmetrical with respect to the horizontal plane and face each other in the vertical direction with the sample S sandwiched therebetween.

[0067] The lower plate 35 has a circular outer insulator region 35b at its outermost periphery. The thickness of the outer insulator region 35b in the direction of radius r is uniform from top to bottom. A disk-shaped lower electrode 42 with the same thickness in the height direction is located on the inner periphery of the outer insulator region 31b. The inner insulator region 35a fills a cylindrical recess formed below the lower electrode 42. The thickness of the inner insulator region 35a in the height direction is approximately 45% of the thickness of the lower plate 35. The upper surface 35c of the lower plate 35 is a horizontal, flat surface such that the inner insulator region 35a, lower electrode 42, and outer insulator region 35b are flush with each other.

[0068] (Action of this embodiment) The physical property measuring device 10 of this embodiment has the following functions. First, the electrode slurry, which is the sample S to be measured, is made of organic solvent S. S In this embodiment, the viscosity is adjusted to a desired value η [Pa·s]. In this embodiment, the viscosity is set to, for example, η=1.000 to 5.000 [Pa·s].

[0069] 1, first, the bottom surface 35d of the lower plate 35 is placed at a predetermined position on the stage 11. At this time, the center of rotation O of the lower plate 35 is placed so as to coincide with the center of rotation O of the rotation shaft 32. The lower electrode 42 of the lower plate 35 is connected to a measurement unit 43 of the impedance measurement device 4.

[0070] Next, the upper plate 31 is attached to the rotating shaft 32. At this time, the rotation center O of the upper plate 31 is set to coincide with the rotation center O of the rotating shaft 32. The upper electrode 41 of the upper plate 31 is connected to the measuring unit 43 of the impedance measuring device 4.

[0071] The upper plate 31 can be raised and lowered by the gap adjustment device 2 to adjust the gap G. For example, a control device (not shown) for the gap adjustment device 2 rotates the spindle 22 using the motor 23 of the gap adjustment device 2 to raise and lower the lift stage 21, thereby adjusting the gap G. Initially, the gap G is set large, and the sample S is placed on the upper surface 35c of the lower plate 35. Then, the control device rotates the spindle 22 using the motor 23 of the gap adjustment device 2 to raise and lower the lift stage 21, and the gap G is adjusted to a predetermined value while measuring the gap G using the encoder 24. In this embodiment, the gap G is set in the range of 0.1 mm to 2.0 mm, for example. The gap G is determined by the viscosity η [Pa·s] of the sample S. If the viscosity η [Pa·s] of the sample S is high, the gap G is set large; if the viscosity η [Pa·s] of the sample S is low, the gap G is set small. In particular, when the viscosity η [Pa s] of the sample S is low and the rotation speed [ω / s] of the measurement motor 33 is high, the gap G is set small so that the sample S does not move radially outward due to centrifugal force, taking into consideration the stability of the sample S. On the other hand, when the viscosity η [Pa s] of the sample S is high, the gap G is set large within the range in which the sample S is stable, so that the resistance [Ω] in the impedance measurement increases.

[0072] Once the adjustment of the gap G is complete, a control device (not shown) of the viscosity measuring device 3 rotates the measurement motor 33 at the set rotation speed [ω / s]. At the same time, it measures the change in the torque M [N m] of the measurement motor 33. The control device (not shown) of the viscosity measuring device 3 detects the rotation speed [ω / s] using a signal from the encoder 34, and calculates the viscosity η [Pa s] of the sample S from the torque M [N m] of the measurement motor 33 based on the gap G for that rotation speed. The viscosity η [Pa s] of the sample S is calculated based on the pre-stored relationship between the rotation speed [ω / s], gap G, and torque M [N m] of the measurement motor 33.

[0073] Meanwhile, at the same time, the measurement unit 43 of the impedance measuring device 4 continuously applies a current [A] or a voltage [V] from high to low frequencies to the sample S from the upper electrode 41 and the lower electrode 42 while changing the frequency [Hz]. Then, the measurement unit 43 measures the resistance [Ω] to the current [A] or voltage [V] applied to the sample S. The measurement unit 43 analyzes this measurement data and outputs the analysis results as a Nyquist plot.

[0074] In this embodiment, the diameter φ of the bottom surface 31c of the upper plate 31 is 50 [mm]. The upper electrode 41 is disposed on a portion of the bottom surface 31c with a width of 1.0 [mm], centered on the circumference of the bottom surface 31c with a radius r3 = 33.3 / 2 [mm]. In other words, it is located at approximately 2 / 3 of the radius r, and its width is 4% of the radius r (2% of the diameter φ). In addition, its area is 1963 [mm], which is the area of ​​the bottom surface 31c. 2 ], 105 [mm 2 ], and the area ratio is approximately 5.6%. In other words, the area of ​​the upper electrode 41 is 1 / 19 of the area of ​​the bottom surface 31c. The lower electrode 42 of the lower plate 35 is also arranged to face the upper electrode 41 in the same position and in the same area. The area where the upper electrode 41 and the lower electrode 42 are arranged is an area where the shear rate D [1 / s] is roughly the same.

[0075] Therefore, the region of the sample S sandwiched between the upper electrode 41 and the lower electrode 42 can be said to be under substantially the same shear rate D [1 / s]. Therefore, the electrical resistance between the upper electrode 41 and the lower electrode 42 substantially reflects the electrical resistance [Ω] of the sample S between the upper electrode 41 and the lower electrode 42. As described above, it is known that impedance measurement is affected by the shear rate D [1 / s]. Therefore, the upper electrode 41 and the lower electrode 42 can measure the electrical resistance [Ω] in a region where the shear rate D [1 / s] is substantially the same. In particular, in this embodiment, the positions at which the upper electrode 41 and the lower electrode 42 are disposed are substantially the average value of the shear rate D [1 / s] generated by the rotation of the sample S, which is believed to enable more accurate impedance measurement.

[0076] In addition, since the shear rate D [1 / s] near the rotation center O of the upper plate 31 and the lower plate 35 is extremely small, the sample S is not sufficiently stirred, and the positive electrode active material S of the electrode slurry A In this embodiment, the positions where the upper electrode 41 and the lower electrode 42 are disposed are sufficiently far from the center of rotation O, so that such a problem is unlikely to occur.

[0077] Furthermore, the shear rate D [1 / s] near the periphery of the upper plate 31 and the lower plate 35 is unstable because the sample S moves outward due to centrifugal force, which may prevent accurate impedance measurement. Furthermore, if electrodes are provided up to the periphery of the upper plate 31 and the lower plate 35, the sample S that moves out from the periphery will adhere to the upper electrode 41 and the lower electrode 42 on the side of the upper plate 31 and the lower plate 35, which also results in a problem of preventing accurate impedance measurement.

[0078] In this embodiment, the positions at which the upper electrode 41 and the lower electrode 42 are arranged are sufficiently far from the center of rotation O and the periphery, and data on the sample S is measured only in the region of the average shear rate D [1 / s], so such problems are less likely to occur and accurate impedance measurements can be performed.

[0079] <Experimental Example> An experimental example of physical property measurement using the physical property measuring apparatus 10 of this embodiment will be described. As shown in FIGS. 3 and 5, in the impedance measurement of this embodiment, the diameter φ of the bottom surface 31c of the upper plate 31 and the lower plate 35 is 50 mm. The upper electrode 41 is disposed on a portion of the bottom surface 31c with a width of 1.0 mm, centered on a circumference with a radius r3 = 33.3 / 2 mm. The lower electrode 42 is disposed in a position always facing the upper electrode 41.

[0080] Graph L1, which shows the Nyquist plot shown in Figure 8, clearly shows the arcs caused by the positive electrode active material SA and the conductive additive SE, compared to graph L2, which shows the Nyquist plot of the prior art where the entire upper plate 31 and lower plate 35 are set as electrodes. Furthermore, the boundary with the straight line portion representing the low frequency is clear, and the straight line portion itself is clearly distinguishable. This enables extremely accurate complex impedance measurement.

[0081] In this experimental example, the shear rate D at the center of the region of the upper electrode 41 was set to 1000 [1 / s]. Therefore, as shown in Fig. 10, by changing the measurement conditions to measure only data near the shear rate D = 1000 [1 / s], it was possible to obtain a Nyquist plot graph L5 that more accurately reflects the impedance characteristics of the sample S.

[0082] In this experimental example, an electrode slurry with a viscosity η of 1.000 [Pa·s] was used as sample S. The gap G was set to 0.1 [mm]. As a result, even when the shear rate D at the center of the upper electrode 41 region was set to 1000 [1 / s], sample S with such a low viscosity η [Pa·s] could be stably held between the upper plate 31 and the lower plate 35 without scattering. Therefore, the viscosity of sample S could be measured accurately and stably.

[0083] (Effects of this embodiment) (1) The physical property measuring device 10 of this embodiment has the advantage that it can accurately measure impedance at the same time as viscosity measurement, even for a sample S such as a slurry having a low viscosity η [Pa·s] and a low electrical resistance [Ω].

[0084] (2) The surface of the upper plate 31 that contacts the sample S is made of an insulator, and the upper electrode 41 of the upper plate 31 is arranged in a ring-shaped band-like region concentric with the rotation axis 32 of the upper plate 31 so that part of the insulator is in electrical contact with the sample S. Therefore, the small electrode area makes it possible to obtain a sufficient electrical resistance [Ω] for measurement even if the gap G is narrow. Furthermore, there is an advantage that impedance can be measured based only on data for the portion with a constant shear rate D [1 / s].

[0085] (3) The upper electrode 41 is an annular electrode arranged in an annular region concentric with the rotation axis 32 of the upper plate 31. Therefore, even if the upper plate 31 rotates, it is possible to measure data only in a fixed region.

[0086] (4) The upper plate 31 has an inner insulator region 31a and an outer insulator region 31b, and the upper electrode 41 is disposed between the inner insulator region 31a and the outer insulator region 31b. This has the effect of reliably blocking data in regions other than the upper electrode 41.

[0087] (5) The radial width of the upper electrode 41 is 2% of the diameter φ of the upper plate 31. This has the effect of enabling impedance measurement based only on data from an extremely limited range of shear rates D [1 / s].

[0088] (6) The lower electrode 42 of the lower plate 35 is disposed only at a position that always faces the upper electrode 41. This has the effect of reliably blocking data other than that of an extremely limited shear rate D [1 / s].

[0089] (7) In this embodiment, the gap G is set to 0.1 mm, which has the effect of preventing the sample S made of electrode slurry from scattering even when rotating at high speed.

[0090] (8) In this embodiment, the shear rate D [1 / s] of the sample S for which the impedance measurement is performed is 1000 [1 / s]. Therefore, the conductive additive S contained in the electrode slurry E Since the measurement can be performed in a state where the particles are sufficiently dispersed, there is an effect that the characteristics of the positive electrode mixture layer formed on the positive electrode can be more accurately estimated.

[0091] (Variation) Although the present invention has been described with reference to the above-described embodiment, the present invention is not limited to the above-described embodiment. The present invention can be implemented, for example, in the following modified forms.

[0092] FIG. 11 is a cross-sectional view of an upper plate 231, a modified example of the upper plate 31, taken along the rotation center O. In this embodiment, the upper plate 31 has a so-called parallel plate configuration, with flat opposing surfaces, as shown in FIGS. 3 and 4. In contrast, the upper plate 231 shown in FIG. 11 has a so-called cone plate configuration. A cone plate has a convex conical opposing surface. The gap G [mm] between the lower plate 35 and the upper plate 231 is, for example, 0.1 [mm] at the rotation center O. The upper plate has side surfaces that slope upward at an angle of approximately 1 degree toward the radially outward direction. Therefore, the gap G is small at 0.1 [mm] at the center of the upper plate 231 and approximately 0.45 [mm] at the periphery. In the upper plate 31 made of parallel plates in this embodiment, the shear rate D [1 / s] is calculated by V / G [1 / s], where V [mm / s] is the speed of movement based on the radius r. In this embodiment, since the gap G [mm] is constant, the shear rate D [1 / s] at the center and peripheral portions depends on the moving speed V [mm / s] based on the radius r. Therefore, the position of the upper electrode 41 for measuring impedance was set to approximately 2 / 3 of the radius r of the upper plate 31.

[0093] On the other hand, in the cone-plate configuration of the upper plate 231 of this modified example, not only the moving speed V [mm / s] but also the gap G [mm] varies depending on the radius r. Therefore, V / G [1 / s] is approximately a constant value at any position on the upper plate 231 of this modified example. Therefore, the configuration of the upper plate 231 of this modified example has the advantage that the arrangement of the upper electrode 41 can be freely selected without depending on the radius r.

[0094] Furthermore, the cone plate is not limited to the upper plate 31, but can also be applied to the lower plate 35. In this case, it is preferable that the upper plate 31 be a parallel plate with flat opposing surfaces.

[0095] In this embodiment, the upper plate 31 is rotationally driven, and the lower plate 35 facing the upper plate 31 is fixed to the stage 11. However, this is not limited to this configuration, and a configuration in which the upper plate 31 is not rotated, but the lower plate 35 is rotationally driven, may be configured to rotate the upper plate 31 and the lower plate 35 relative to each other.

[0096] FIG. 12 is a cross-sectional view of a lower plate 235, a modified example of the lower plate 35 of the present embodiment, taken along the rotation center O. FIG. 13 is a plan view of a lower plate 235, a modified example of the lower plate 35 of the present embodiment. The lower plate 35 of the present embodiment includes the upper electrode 41 and the lower electrode 42, which are inverted upside down, as shown in FIGS. 5 and 6. In contrast, in the lower electrode 242 of this modified example, the entire lower plate 235 is formed of a conductive material, such as SUS or Al. In other words, the entire lower plate 235 serves as the lower electrode 242. The upper electrode 41 of this modified example has the same configuration as the present embodiment, as shown in FIGS. 3 and 4. Therefore, in this embodiment, the range to which a voltage [V] or a current [A] is applied by the impedance measuring device 4 is only the portion where the upper electrode 41 and the lower electrode 42 face each other. In this modified example, the current-carrying range also depends on the portion where the upper electrode 41 is disposed. However, compared to the lower electrode 42 of the present embodiment, in the lower electrode 242 of the modified example, the voltage [V] or current [A] applied to the upper electrode 41 flows over a wider range than in the lower electrode 42. For this reason, when evaluating only the accuracy of the impedance measurement, it cannot be denied that the accuracy is somewhat reduced.

[0097] On the other hand, the lower electrode 242 of this modified example has the advantage of being simple in structure. Furthermore, because temperature [°C] has a significant effect on not only impedance measurement but also viscosity measurement of the sample S, it is important to maintain the sample S at a constant temperature [°C]. For this reason, the lower plate 235 is provided with a structure for heating and cooling. A method of maintaining the temperature by contacting the lower plate 235 with the sample S and using conductive heat has been used in the past, including this embodiment. In this case, the lower plate 35 of this embodiment uses an insulator made of polyacetal resin (POM resin) in part. Insulators made of polyacetal resin (POM resin) also have low thermal conductivity, reducing the efficiency of heating and cooling. From this perspective, the configuration in which the lower electrode 242 of this modified example is the entire lower plate 235 has the advantageous effect of extremely high heating and cooling efficiency.

[0098] Although an example has been described in which the entire lower plate 35 is an electrode, this is not limited to this, and the entire upper plate 31 may be an electrode, and the lower plate 35 may be configured so that the lower electrode 42 is disposed in at least a part of a ring-shaped band area concentric with the rotation center O of the lower plate 35.

[0099] FIG. 14 is a bottom view of an upper plate 431 of another modified example of the upper plate 31 of this embodiment. In the upper plate 31 of this embodiment, the upper electrode 41 is formed circumferentially. However, considering that the upper plate 331 of this modified example rotates around the rotation center O, it is not necessary to provide the upper electrode 41 around the entire circumference. As shown in FIG. 14, even if only a portion of the upper electrode 41 of the upper plate 31 of this embodiment is formed in an arc shape, the same effect as this embodiment can be obtained. Furthermore, such a configuration has the effect of facilitating manufacturing. While the upper plate 31 is exemplified here, this is not limiting, and the lower plate 35 may also have an arc-shaped electrode.

[0100] 15 is a bottom view of an upper plate 431, which is yet another modification of the upper plate 31. The upper electrode 41 does not necessarily have to be strip-shaped, but can also be a circular electrode. Of course, it is not limited to a circular shape, and an elliptical or rectangular shape can also be used. Such a configuration has the advantage of being even easier to manufacture.

[0101] In this embodiment, the diameter φ of the upper plate 31 is exemplified as 50 mm. However, the diameter φ of the upper plate 31 is not limited to 50 mm, and a diameter of 25 mm, for example, can also be used. Furthermore, a larger or smaller diameter φ can also be used.

[0102] The upper plate 31 in this embodiment is illustrated as a cylindrical disk. However, as long as the opposing surfaces are flat, the shape is not limited, and the upper plate may have a convex shape. Although the details of the connection between the upper plate 31 and the rotating shaft 32 are omitted, it goes without saying that various mounting structures can be used.

[0103] In this embodiment, the upper electrode 41 on the upper plate 31 is centered at approximately 2 / 3 of the radius r. This is because it is preferable that this position corresponds to the average shear rate D [1 / s] across the entire upper plate 31. However, this position is not necessarily limited to this. For example, if the viscosity η [Pa s] of the sample S is low, the upper electrode 41 can be positioned closer to the center of rotation O. Furthermore, if dispersion of the sample S is desired at a sufficient shear rate D [1 / s], the upper electrode 41 can be positioned closer to the periphery.

[0104] In particular, in the case of the upper plate 231 having the cone-plate configuration shown in Fig. 11, the shear rate D [1 / s] is constant at any position of radius r. Therefore, the shear rate D [1 / s] is not restricted and can be set freely.

[0105] In this embodiment, the radial width of the upper electrode 41 is set to 2% of the diameter φ of the upper plate 31. However, this width is not limited to this. For example, a range of 1 to 50% of the diameter φ of the upper plate 31 is suitable. More specifically, when the sample S is an electrode slurry and the diameter φ of the upper plate 31 is 50 mm, the radial width of the upper electrode 41 can be 0.5 mm or more and 20 mm or less. Furthermore, when the diameter φ of the upper plate 31 is 25 mm, the radial width of the upper electrode 41 can be 0.5 mm or more and 7.5 mm or less. Of course, this range is not limited to these ranges because it depends on the physical properties of the sample S.

[0106] Although the sample S in this embodiment is an electrode slurry for a positive electrode of a lithium-ion secondary battery, the sample S is not limited to this and can also be applied to a negative electrode slurry and electrode slurries for other types of batteries. Furthermore, the sample S can be widely applied to materials that have a relatively low electrical resistance [Ω] and a relatively low viscosity η [Pa s], not limited to batteries.

[0107] The physical property measuring device 10 illustrated in FIG. 1 is a schematic illustration of its function, and the configurations of the support 1, gap adjustment device 2, viscosity measuring device 3, and impedance measuring device 4 are not limited to those in the embodiment as long as they can perform their functions.

[0108] Although the upper plate 31 is made of polyacetal resin (POM resin) as an insulator and Cu as a conductor, other materials may be used as long as they function as an insulator and a conductor. The same applies to the material of the lower plate 35.

[0109] The gap G is, for example, 0.1 mm, but can be adjusted depending on the viscosity η [Pa·s] of the sample S. For example, A Depending on the particle size and the electrical resistance [Ω] of the electrode slurry, the gap may be even closer. Conversely, if the viscosity η [Pa s] of the sample S is high and the electrical resistance [Ω] is low, the gap G may be set to, for example, more than 2.0 [mm].

[0110] In this embodiment, the shear rate D [1 / s] for impedance measurement is set to 1000 [1 / s], but this can be increased or decreased depending on the viscosity η [Pa·s] of the sample S.

[0111] It goes without saying that the present invention can be implemented by those skilled in the art by adding, deleting, or modifying its configuration without departing from the scope of the claims. Furthermore, it goes without saying that the numerical values ​​exemplified can be optimized by those skilled in the art. [Explanation of symbols]

[0112] τ [Pa]...shear stress D [1 / s]...shear velocity (velocity gradient) D r1 ~D r4 [1 / s]…Shear rate at radius r ω…angular velocity η[Pa·s]…Viscosity (=S / D) M [N m]...torque E [V]...Voltage Z [Ω]...Impedance O...Center of rotation G...Gap L 1~6 ...Graph of Nyquist plot S...Sample (electrode slurry) S A ...Cathode active material S E …Conductive additive S S …organic solvent 10...Physical property measuring device 1...Support 11...Stage 12...Column 2...Gap adjustment device 21...Lifting stage 22...Spindle 23...Motor 24...Encoder 3...Viscosity measuring device 31...Upper plate (upper measuring part) 31a...Inner insulator region 31b...Outer insulator area 31c…Bottom surface 31d…Top surface 32...Rotation axis 33...Measurement motor 34...Encoder 35...Lower plate (lower measuring part) 35a...Inner insulator region 35b...Outer insulator area 35c…Top surface 35d…Bottom surface 4. Impedance measuring device 41...Top electrode 42...lower electrode 43… Measurement Department

Claims

1. a measuring section in which an upper measuring section and a lower measuring section disposed below the upper measuring section so as to face each other are arranged so as to be rotatable relative to each other; a viscosity measuring device that calculates a shear stress τ [Pa] from the cross-sectional area of ​​a sample sandwiched between the upper measurement part and the lower measurement part, and a shear rate [1 / s] from the radius of the sample and the gap between the upper measurement part and the lower measurement part, based on the torque and rotation speed when the upper measurement part and the lower measurement part rotate relative to each other, and measures a viscosity η [Pa s] of the sample; an impedance measuring device provided with electrodes consisting of an upper electrode of the upper measuring section and a lower electrode of the lower measuring section, the impedance measuring device measuring the impedance of the sample using the upper electrode and the lower electrode; A physical property measuring device characterized in that the surface of at least one of the upper measurement unit and the lower measurement unit that contacts the sample is made of an insulator, and at least one of the upper electrode of the upper measurement unit and the lower electrode of the lower measurement unit is arranged in at least a part of an annular band-shaped region concentric with the center of rotation of the upper measurement unit and the lower measurement unit so as to be in electrical contact with the sample at a part of the insulator.

2. 2. The physical property measuring device according to claim 1, wherein at least one of the upper measuring section and the lower measuring section has a facing surface formed in a flat disk shape.

3. 2. The physical property measuring device according to claim 1, wherein at least one of the upper measuring section and the lower measuring section has a facing surface formed in a conical shape.

4. 4. The physical property measuring device according to claim 1, wherein the electrode is an annular or arc-shaped electrode arranged in an annular region concentric with the center of rotation of the measuring unit.

5. The physical property measuring device according to any one of claims 1 to 3, characterized in that the electrode is one or more circular electrodes arranged in a part of an annular region concentric with the center of rotation of the measuring unit.

6. The physical property measuring device of claim 1, characterized in that at least one of the upper measuring section and the lower measuring section has an inner insulator region and an outer insulator region, and the electrode is arranged between the inner insulator region and the outer insulator region.

7. 2. The physical property measuring device according to claim 1, wherein the radial width of the electrode is 1% or more and 50% or less of the diameter of the measuring portion.

8. 2. The physical property measuring device according to claim 1, wherein at least one of the upper measuring section and the lower measuring section is made of a conductor, and the entire upper measuring section or the entire lower measuring section is configured as the electrode.

9. 2. The physical property measuring device according to claim 1, wherein the upper measuring section and the lower measuring section are formed by the insulator, and the upper electrode and the lower electrode are arranged circumferentially on a part of the insulator so as to face each other.

10. 2. The physical property measuring apparatus according to claim 1, wherein the sample is an electrode slurry.

11. 11. The physical property measuring device according to claim 10, wherein the electrode slurry contains a conductive additive for a positive electrode of a lithium ion secondary battery.

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