Dispersion storage device and storage method

Abstract

To provide a storage unit for maintaining a proper particle dispersion state while restraining particle precipitation and flowability lowering in a stored dispersion liquid.SOLUTION: A storage unit in an embodiment comprises a vessel, impeller, dispersion blade, detection part, and control part. The impeller enables autorotation around a first shaft as a center in an internal cavity of the vessel. The dispersion blade enables autorotation in a larger revolution than that of the impeller around a second shaft different from the first shaft as the center in the internal cavity and further, the second shaft enables revolution in a smaller revolution than that of autorotation of the dispersion blade around the first shaft as the center. The detection part can detect a dispersion state of particles in a dispersion liquid, and the control part can control the impeller and dispersion blade based on a detection result.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION Embodiments of the present invention relate to a storage device and method for a dispersion. [Background technology]

[0002] In the storage of a dispersion liquid such as a slurry for forming an active material-containing layer of an electrode in a battery, a storage device having a container capable of storing the dispersion liquid is used. In such a storage device, an agitator blade is disposed in the internal cavity of the container, and the agitator blade is rotated while the dispersion liquid is stored in the container, thereby suppressing particle settling and a decrease in fluidity of the dispersion liquid.

[0003] Here, the dispersion liquid stored in the container may be one in which particles tend to aggregate together. When a dispersion liquid in which particles tend to aggregate together is stored in a container, it is required to suppress particle settling and a decrease in fluidity, as described above, in the stored dispersion liquid, and to appropriately redisperse the aggregated particles. It is also required to maintain the particles in an appropriately dispersed state in the stored dispersion liquid. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-168189 [Patent Document 2] International Publication No. 2016 / 039067 [Patent Document 3] Japanese Patent Application Laid-Open No. 2016-46188 Summary of the Invention [Problem to be solved by the invention]

[0005] The problem to be solved by the present invention is to provide a storage device and a storage method that suppresses sedimentation of particles and a decrease in fluidity in a stored dispersion liquid, and maintains an appropriate dispersion state of the particles. [Means for solving the problem]

[0006] According to an embodiment, the dispersion storage device comprises a container, an agitating blade, a dispersing blade, a detection unit, and a control unit. The container is capable of storing the dispersion in an internal cavity, and the agitating blade is capable of rotating about a first axis in the internal cavity of the container. The dispersing blade is capable of rotating about a second axis different from the first axis in the internal cavity of the container at a rotation speed greater than the rotation speed of the agitating blade, and the second axis is capable of revolving about the first axis at a rotation speed smaller than the rotation speed of the agitating blade. The detection unit is capable of detecting the dispersion state of particles in the dispersion stored in the internal cavity. The control unit is capable of controlling the rotation operation of the agitating blade and the rotation and revolution operation of the dispersing blade based on the detection result by the detection unit. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram illustrating an example of a storage device according to an embodiment. [Figure 2] FIG. 2 is a schematic view showing an example of an agitating blade of the storage device according to the embodiment. [Figure 3] FIG. 3 is a perspective view schematically illustrating an example of a dispersion blade of the storage device according to the embodiment. [Figure 4] FIG. 4 is a schematic diagram showing the internal cavity of the container and the stirring blades and dispersing blades arranged in the internal cavity in the storage device according to the embodiment, as viewed from vertically above. [Figure 5] FIG. 5 is a schematic diagram showing an example of the configuration of the circulation flow path and its vicinity in the storage device according to the embodiment. [Figure 6] FIG. 6 is a schematic diagram showing another example of the configuration of the circulation flow path and its vicinity in the storage device according to the embodiment, different from that shown in FIG. [Figure 7] FIG. 7 is a flowchart schematically showing an example of processing in the operation control of the stirring blades and dispersing blades, which is performed by the control unit according to the embodiment. [Figure 8]FIG. 8 is a flowchart schematically illustrating an example of a process performed by the control unit according to the embodiment to calculate an index relating to the dispersion state of particles from an image showing the dispersion state of particles in a dispersion liquid. [Figure 9] FIG. 9 is a schematic diagram showing an example of a process performed by the control unit according to the embodiment to calculate the particle size of a carbon material from an image showing the dispersion state of the particles in a dispersion liquid. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments will be described with reference to the drawings.

[0009] FIG. 1 shows an example of a storage device 1 according to an embodiment. As shown in FIG. 1, the storage device 1 includes a container (tank) 2, an agitator blade 3, a dispersing blade 5, a detector 6, and a controller 7. An internal cavity 8 is formed inside the container 2, and the container 2 has a central axis (not shown) along the vertical direction (the direction indicated by arrow Z). The internal cavity 8 of the container 2 can store a dispersion liquid L. An example of the dispersion liquid L is a slurry that forms an active material-containing layer of an electrode in a battery such as a lithium-ion secondary battery. When the slurry that forms the active material-containing layer is the dispersion liquid L, the dispersion liquid L may contain particles of a carbon material.

[0010] The storage device 1 is also formed with a supply flow path 11 that supplies the dispersion L to the internal cavity 8 of the container 2, and a discharge flow path 12 that discharges the dispersion L from the internal cavity 8. The dispersion L prepared in a previous step or the like is supplied to the internal cavity 8 through the supply flow path 11 by, for example, discharging or pressure-feeding using a pump (arrow F1 in FIG. 1). In one example, an on-off valve (not shown) is provided at the connection portion of the discharge flow path 12 to the internal cavity 8, and by opening the on-off valve, the dispersion L is discharged from the internal cavity 8 through the discharge flow path 12 (arrow F2 in FIG. 1).

[0011] FIG. 2 shows an example of an agitator impeller 3. In the example shown in FIG. 2, the agitator impeller 3 includes a shaft portion 15, a pair of blade portions 16, and a pair of relay portions 17. The shaft portion 15 and the pair of blade portions 16 each extend vertically. The agitator impeller 3 is disposed in the internal cavity 8 such that the central axis of the shaft portion 15 is coaxial or approximately coaxial with the central axis of the container 2. In the internal cavity 8, each of the pair of blade portions 16 is disposed on the outer circumferential side of the shaft portion 15. In addition, in the example shown in FIGS. 1 and 2, the pair of blade portions 16 are disposed 180° or approximately 180° apart from each other in the axial direction around the central axis of the shaft portion 15 (the circumferential direction of the internal cavity 8). Each of the pair of relay portions 17 connects the vertically lower end of the shaft portion 15 to the vertically lower end of a corresponding one of the pair of blade portions 16. Due to the above-described configuration, the agitating impeller 3 has the shaft portion 15, the pair of blade portions 16, and the pair of relay portions 17 forming a W-shape or an approximately W-shape.

[0012] FIG. 3 shows an example of a dispersion impeller 5. In the example shown in FIG. 3, the dispersion impeller 5 includes a shaft portion 21 and a base plate portion 22. The shaft portion 21 extends vertically, and the base plate portion 22 is connected to the vertically lower end of the shaft portion 21. In the dispersion impeller 5, the central axis of the shaft portion 21 is coaxial or approximately coaxial with the central axis of the base plate portion 22. A plurality of blade portions 23 are formed on the outer peripheral end of the base plate portion 22. The plurality of blade portions 23 are arranged side by side along the circumferential direction of the base plate portion 22, and the outer peripheral end of the base plate portion 22 is formed into a jagged or uneven shape around the entire circumference of the base plate portion 22 by the plurality of blade portions 23. Furthermore, in the base plate portion 22, each of the plurality of blade portions 23 is bent toward a portion on the inner peripheral side relative to the blade portion 23. The dispersion impeller 5 is arranged on the outer peripheral side of the shaft portion 15 of the agitator impeller 3 in the internal cavity 8.

[0013] FIG. 4 shows the internal cavity 8 of the container 2 and the agitator 3 and disperser 5 disposed in the internal cavity 8, viewed from vertically above. As shown in FIGS. 1, 2, and 4, the agitator 3 is rotatable about an axis (first axis) R1 in the internal cavity 8. The axis R1 is coaxial or approximately coaxial with the central axis of the shaft portion 15 and is also coaxial or approximately coaxial with the central axis of the container 2. When the dispersion L is stored in the internal cavity 8 of the container 2, the agitator 3 rotates on its axis (arrow A1 in FIGS. 1 and 4), thereby stirring the dispersion L. Stirring the dispersion L using the agitator 3 suppresses particle settling and a decrease in fluidity in the dispersion L. In the example shown in FIG. 4, the agitator 3 rotates in the direction of arrow A1, but the agitator 3 may also rotate in the direction opposite to arrow A1.

[0014] As shown in Figures 1 and 4, in the internal cavity 8, the dispersion blade 5 is disposed on the outer periphery of the axis R1. The dispersion blade 5 is rotatable about an axis (second axis) R2 in the internal cavity 8. The axis R2 is aligned vertically and is coaxial or substantially coaxial with the central axis of the shaft portion 21. The axis R2 is located on the outer periphery of the axis R1 in the internal cavity 8. Even if particles aggregate in the dispersion liquid L stored in the internal cavity 8 of the container 2, the dispersion blade 5 rotates (arrow B1 in Figures 1 and 4), and a shear force acts on the particle aggregates, i.e., on aggregated particles formed by aggregating a large number of particles. This redisperses the aggregated particles. While the dispersion blade 5 rotates in the direction of arrow B1 in the example shown in Figure 4, the dispersion blade 5 may also rotate in the opposite direction to arrow B1.

[0015] Furthermore, the dispersion impeller 5 can revolve around the axis (first axis) R1, which is the central axis of the rotation of the agitator 3. That is, the dispersion impeller 5 can revolve around the axis R2 (a second axis different from the first axis), which is the central axis of the rotation of the dispersion impeller 5, in the direction around the axis R1, which is the central axis of the rotation of the agitator 3 (the circumferential direction of the shaft portion 15 of the agitator 3). As the dispersion impeller 5 revolves (i.e., the central axis R2 of the rotation of the dispersion impeller 5 rotates around the central axis R1 of the rotation of the agitator 3) (arrow B2 in Figures 1 and 4), the region in the dispersion L stored in the internal cavity 8 where aggregated particles are redispersed by the rotation of the dispersion impeller 5 changes. Furthermore, as the dispersion impeller 5 revolves, the dispersion L stored in the internal cavity 8 is stirred even when the agitator 3 is not rotating.

[0016] The storage device 1 is equipped with drive sources 25 and 26. Drive source 25 is provided with a drive member such as a motor. By driving the drive member in drive source 25, the agitator blade 3 rotates around axis R1 as described above. Drive source 26 is provided with one or more drive members such as a motor. By driving the drive member in drive source 26, the dispersion blade 5 rotates around axis R2 as described above and revolves around axis R1 as described above. In one example, by driving one drive member in drive source 26, both power to rotate the dispersion blade 5 and power to revolve the dispersion blade 5 are generated. In another example, drive source 26 is provided with a drive member that generates power to rotate the dispersion blade 5 when driven and a drive member that generates power to revolve the dispersion blade 5 when driven, as separate members.

[0017] The control unit (controller) 7 is configured, for example, by one or more computers, and includes a processor or integrated circuit, and a storage medium such as a memory. The processor or integrated circuit includes any of a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), a microcomputer, an FPGA (Field Programmable Gate Array), and a DSP (Digital Signal Processor). The control unit 7 may include only one processor or multiple processors. In one example, the control unit 7 is configured by a server in a cloud environment. In this case, the control unit 7 includes a virtual processor such as a virtual CPU and cloud memory.

[0018] The control unit 7 can control the rotational motion of the agitating blade 3 by controlling the drive of the drive source 25, and controls the rotational motion of the agitating blade 3. The control unit 7 can control the rotational motion and revolutional motion of the dispersing blade 5 by controlling the drive of the drive source 26, and controls the rotational motion and revolutional motion of the dispersing blade 5. The rotational speed (rotational speed) of the dispersing blade 5 is faster (greater) than the rotational speed (agitating blade rotational speed) of the agitating blade 3. The revolutional speed (revolutional speed) of the dispersing blade 5 is slower (smaller) than the rotational speed of the agitating blade 3. In one example, the rotational speed of the agitating blade 3 is 40 rpm or more and 50 rpm or less. The rotational speed of the dispersing blade 5 is 500 rpm or more and 1000 rpm or less, and the revolutional speed of the dispersing blade 5 is 10 rpm or more and 20 rpm or less. The rotation speed of the agitating blade 3 (agitating blade rotation speed), the rotation speed of the dispersing blade 5 (dispersing blade rotation speed), and the revolution speed of the dispersing blade 5 (dispersing blade revolution speed) may each be variable within a predetermined range. Even in this case, it is preferable to set the minimum value of the dispersing blade rotation speed to be greater than the maximum value of the agitating blade rotation speed, and the maximum value of the dispersing blade revolution speed to be smaller than the minimum value of the agitating blade rotation speed.

[0019] The detection unit 6 is capable of detecting the dispersion state of particles in the dispersion liquid L stored in the internal cavity 8, and detects the dispersion state of particles in the dispersion liquid L. In one example, such as FIG. 1 , the storage device 1 is provided with a circulation flow path 30 that can communicate with the internal cavity 8 of the container 2. The dispersion liquid L can be introduced into the circulation flow path 30 from the internal cavity 8, and the dispersion liquid L introduced into the circulation flow path 30 can be discharged to the internal cavity 8. In one example, such as FIG. 1 , the detection unit 6 detects the dispersion state of particles in the dispersion liquid L in the circulation flow path 30.

[0020] FIG. 5 shows an example of the configuration of the circulation flow path 30 and its vicinity. In the example shown in FIG. 5, the circulation flow path 30 has an inlet 31 and an outlet 32, and is connected to the internal cavity 8 at each of the inlet 31 and the outlet 32. In the circulation flow path 30, the dispersion state of particles in the dispersion liquid L is detected by the detection unit 6 in the inspection region 33. A pump 35 is disposed in the circulation flow path 30, and the operation of the pump 35 is controlled by, for example, the control unit 7. By operating the pump 35, the dispersion liquid L is introduced from the internal cavity 8 through the inlet 31 into the circulation flow path 30. The dispersion liquid L introduced into the circulation flow path 30 is then discharged into the internal cavity 8 through the outlet 32. Therefore, by operating the pump 35, the dispersion liquid L circulates between the internal cavity 8 and the inspection region 33 of the circulation flow path 30 (arrow F3 in FIG. 5). The detection unit 6 detects the dispersion state of particles in the dispersion liquid L in the inspection area 33 while the dispersion liquid L is circulating between the internal cavity 8 and the inspection area 33 .

[0021] FIG. 6 shows another example of the configuration of the circulation flow path 30 and its vicinity, different from that shown in FIG. 5 . In the example shown in FIG. 6 , similar to the example shown in FIG. 5 , the circulation flow path 30 has an inlet 31 and an outlet 32, and a pump 35 is disposed in the circulation flow path 30. In the circulation flow path 30, the dispersion state of particles in the dispersion liquid L is detected by a detection unit 6 in an inspection region 33. However, in this example, an on-off valve 36 is disposed in the inlet 31, and an on-off valve 37 is disposed in the outlet 32. At the inlet 31, the dispersion liquid L can be introduced from the internal cavity 8 into the circulation flow path 30 only when the on-off valve 36 is open. When the on-off valve 36 is closed, the dispersion liquid L is not introduced from the internal cavity 8 into the circulation flow path 30. Furthermore, at the outlet 32, the dispersion liquid L can be discharged from the circulation flow path 30 to the internal cavity 8 only when the on-off valve 37 is open. When the on-off valve 37 is closed, the dispersion liquid L is not discharged from the circulation flow path 30 to the internal cavity 8. The opening and closing of the on-off valves 36 and 37 is controlled by the control unit 7, for example.

[0022] In the example shown in FIG. 6 , a bypass flow path 38 is formed in parallel to the testing region 33 of the circulation flow path 30. One end of the bypass flow path 38 communicates with the circulation flow path 30 at a position closer to the inlet 31 of the testing region 33 and the pump 35. The other end of the bypass flow path 38 communicates with the circulation flow path 30 at a position closer to the outlet 32 ​​of the testing region 33 and the pump 35. When detection is performed using the detection unit 6, the pump 35 is operated with the on-off valves 36 and 37 open to circulate the dispersion liquid L between the internal cavity 8 and the testing region 33 of the circulation flow path 30. Then, while the dispersion liquid L is circulating between the internal cavity 8 and the testing region 33, the on-off valves 36 and 37 are closed with the pump 35 still operating. This prevents the dispersion liquid L from being introduced from the internal cavity 8 into the circulation flow path 30, and prevents the dispersion liquid L from being discharged from the internal cavity 8 into the circulation flow path 30. Then, the dispersion liquid L circulates between the inspection region 33 and the bypass flow path 38 of the circulation flow path 30 (arrow F4 in FIG. 6). The detection unit 6 detects the dispersion state of particles in the dispersion liquid L in the inspection region 33 while the dispersion liquid L circulates between the bypass flow path 38 and the inspection region 33.

[0023] In one example, the detection unit 6, in detecting the dispersion state of particles in the dispersion liquid L, acquires an image showing the dispersion state of particles in the dispersion liquid L. That is, an image showing the dispersion state of particles in the dispersion liquid L is acquired as a detection result of the detection unit 6. In this case, detection by the detection unit 6 is performed in either the example configuration of FIG. 5 or the example configuration of FIG. 6. The detection unit 6 includes an imaging device such as a camera, and in detection by the detection unit 6, an image of the dispersion liquid L circulating between the internal cavity 8 or the bypass flow path 38 in the inspection region 33 is acquired. As a result, an image showing the dispersion state of particles in the dispersion liquid L is acquired.

[0024] In another example, the detection unit 6 measures the viscosity of the dispersion liquid L when detecting the dispersion state of the particles in the dispersion liquid L. That is, the viscosity of the dispersion liquid L is obtained as the detection result of the detection unit 6. In this case, detection is performed by the detection unit 6 in the example configuration of FIG. 6. The detection unit 6 includes a viscometer, and in detection by the detection unit 6, the viscosity of the dispersion liquid L circulating between the inspection area 33 and the bypass flow path 38 is measured. The more aggregated the particles are in the dispersion liquid L, the higher the viscosity of the dispersion liquid L, and the more dispersed the particles are in the dispersion liquid L, the lower the viscosity of the dispersion liquid L.

[0025] In another example, when detecting the dispersion state of particles in the dispersion liquid L, the detection unit 6 measures a parameter indicating the mobility of molecules in the dispersion liquid L by a pulsed NMR (Nuclear Magnetic Resonance) method. That is, the parameter indicating the mobility of molecules in the dispersion liquid L is acquired as the detection result of the detection unit 6. In this case, detection by the detection unit 6 is performed in the example configuration of FIG. 6. Then, in the inspection region 33, a magnetic field is applied in a pulsed manner to the dispersion liquid L circulating between the inspection region 33 and the bypass flow path 38. By applying the magnetic field in a pulsed manner, the nuclear spins of protons in the dispersion liquid L are excited, and the magnetization intensity of the dispersion liquid L circulating through the inspection region 33 increases. Then, after a certain amount of time has passed since the magnetic field was applied in a pulsed manner, the nuclear spins of protons in the dispersion liquid L return from the excited state to the ground state, and the magnetization intensity of the dispersion liquid L decreases to its original magnitude.

[0026] In this example, the detection unit 6 measures the relaxation time, which is the time required for the nuclear spins of protons in the dispersion L in which the nuclear spins are in an excited state to return to the ground state, as a parameter indicating the mobility of molecules in the dispersion L. At this time, the detection unit 6 measures the time change in magnetization intensity from the time when a pulsed magnetic field is applied to the dispersion L circulating through the inspection region 33. Then, the time required for the magnetization intensity increased by the application of the magnetic field to return to its original magnitude is measured as the relaxation time. The more aggregated the particles in the dispersion L, the longer the relaxation time measured as described above. And, the more dispersed the particles in the dispersion L, the shorter the relaxation time.

[0027] Note that detection of the dispersion state of particles in the dispersion liquid L may involve one or more of acquiring an image showing the dispersion state of particles in the dispersion liquid L, measuring the viscosity of the dispersion liquid L, and measuring a parameter showing the mobility of molecules in the dispersion liquid L by pulsed NMR. Therefore, in one example, detection of the dispersion state of particles in the dispersion liquid L may involve more than one of acquiring an image showing the dispersion state of particles in the dispersion liquid L, measuring the viscosity of the dispersion liquid L, and measuring a parameter showing the mobility of molecules in the dispersion liquid L by pulsed NMR.

[0028] The control unit 7 acquires the detection results by the detection unit 6 regarding the dispersion state of particles in the dispersion liquid L. To this end, the control unit 7 acquires one or more of the following as the detection results by the detection unit 6: an image showing the dispersion state of particles in the dispersion liquid L, a measurement result of the viscosity of the dispersion liquid L, and a measurement result of a parameter showing the mobility of molecules in the dispersion liquid L, such as the measurement result of the relaxation time described above. Based on the detection results by the detection unit 6, the control unit 7 controls the rotation of the agitating blade 3 and the rotation and revolution of the dispersing blade 5.

[0029] 7 shows an example of a process for controlling the operation of the agitating blade 3 and the dispersing blade 5, which is performed by the control unit 7 in this embodiment. The process of the example in FIG. 7 is performed periodically while the dispersion liquid L is stored in the internal cavity 8 of the container 2. The process of the example in FIG. 7 is started in any of the following states: only the agitating blade 3 rotates on its axis and the dispersing blade 5 does not rotate or revolve; only the dispersing blade 5 rotates and revolves on its axis and the agitating blade 3 does not rotate; or the agitating blade 3 rotates on its axis and the dispersing blade 5 rotates and revolves on its axis.

[0030] When the processing of the example of FIG. 7 is started, the control unit 7 acquires an index related to the dispersion state of the particles in the dispersion liquid L based on the detection result of the detection unit 6 (S101). At this time, for example, if the viscosity of the dispersion liquid L is measured in the detection by the detection unit 6, the measured viscosity of the dispersion liquid L is acquired as an index related to the dispersion state of the particles. Also, if a parameter indicating the mobility of molecules in the dispersion liquid L, such as the relaxation time described above, is measured, the measured parameter is acquired as an index related to the dispersion state of the particles. Also, if an image indicating the dispersion state of the particles in the dispersion liquid L is acquired by the detection by the detection unit 6, the control unit 7 calculates an index related to the dispersion state of the particles by, for example, image processing the image indicating the dispersion state of the particles.

[0031] Then, the control unit 7 determines whether or not the particles in the dispersion L have aggregated beyond a reference level based on the acquired index (S102). At this time, for example, if the viscosity of the dispersion L is acquired as the index, the control unit 7 sets a threshold value for the viscosity of the dispersion L. Then, if the measured viscosity of the dispersion L is equal to or greater than the threshold value, the control unit 7 determines that the particles in the dispersion L have aggregated beyond the reference level. On the other hand, if the measured viscosity of the dispersion L is smaller than the threshold value, the control unit 7 determines that the aggregation state of the particles in the dispersion L does not exceed the reference level.

[0032] Furthermore, when the aforementioned relaxation time is acquired as the index, the control unit 7 sets a threshold value for the relaxation time. Then, when the measured relaxation time is equal to or greater than the threshold value, the control unit 7 determines that the particles in the dispersion L have aggregated beyond the reference level. On the other hand, when the measured relaxation time is shorter than the threshold value, the control unit 7 determines that the aggregation state of the particles in the dispersion L does not exceed the reference level. Furthermore, when the index is calculated by image processing an image showing the dispersion state of the particles, the control unit 7 sets a threshold value for the calculated index. Then, the control unit 7 determines whether the particles in the dispersion L have aggregated beyond the reference level based on whether the calculated index is equal to or greater than the threshold value, etc.

[0033] If the aggregation state of particles in the dispersion L does not exceed the reference level (S102-No), the control unit 7 rotates the agitating impeller 3 (S103). At this time, the dispersing impeller 5 does not rotate or revolve. On the other hand, if particles in the dispersion L are aggregated above the reference level (S102-Yes), the control unit 7 rotates the agitating impeller 3 (S104). Then, the control unit 7 rotates and revolves the dispersing impeller 5 (S105). Therefore, the control unit 7 rotates and revolves the dispersing impeller 5 based on the fact that particles in the dispersion L are aggregated above the reference level. In one example, if particles in the dispersion L are aggregated above the reference level, the process of S104 is not performed, and the control unit 7 does not rotate the agitating impeller 3. In this case, the control unit 7 also performs the process of S105 and rotates and revolves the dispersing impeller 5 based on the fact that particles in the dispersion L are aggregated above the reference level.

[0034] In one example, such as FIG. 7 , if the particle aggregation state in the dispersion L does not exceed the reference level, the control unit 7 continues to rotate the agitating blade 3 until the next determination of whether the particles have aggregated beyond the reference level. In another example, if the particles in the dispersion L have aggregated beyond the reference level, the control unit 7 continues to rotate and revolve the dispersion blade 5 until the next determination of whether the particles have aggregated beyond the reference level. In another example, after determining that the particles in the dispersion L have aggregated beyond the reference level, the control unit 7 continues to rotate and revolve the dispersion blade 5 for a specified time. Then, at the end of the specified time, the control unit 7 stops the rotation and revolution of the dispersion blade 5. Then, from the end of the specified time until the next determination of whether the particles have aggregated beyond the reference level, the control unit 7 continues to rotate the agitating blade 3. At this time, the dispersion blade 5 does not rotate or revolve.

[0035] Fig. 8 shows an example of a process for calculating an index related to the dispersion state of particles from an image showing the dispersion state of particles in the dispersion liquid L. The process of the example of Fig. 8 corresponds to the process of S101 of the example of Fig. 7. Before performing the process of the example of Fig. 8, the control unit 7 acquires an image showing the dispersion state of particles in the dispersion liquid L as a detection result by the detection unit 6. Furthermore, in the example of Fig. 8, the dispersion liquid L is, for example, a slurry or the like that forms an active material-containing layer in a battery electrode, and contains a carbon material.

[0036] When the process of the example of FIG. 8 is started, the control unit 7 performs a process for increasing contrast and an edge detection process on the acquired image to detect particles contained in the dispersion liquid L from the image (S111). At this time, in addition to fine particles, aggregated particles formed by aggregating a large number of fine particles are also detected as particles. The control unit 7 then detects carbon material particles from the detected particles based on the brightness and color of the image (S112). At this time, for example, particles whose darkness exceeds a reference value among the particles detected in S111 are detected as carbon material particles. Particles detected as carbon material particles include fine carbon material particles and aggregated particles formed by aggregating a large number of carbon material fine particles.

[0037] Then, the control unit 7 sets a rectangle for each detected carbon material particle so that the entire particle of the carbon material is included (S113). Each rectangle is set to the smallest size possible within the range that includes the entire particle of the corresponding carbon material. The control unit 7 then calculates the length of the long side for each set rectangle (S114). The control unit 7 then calculates the average length of the long sides of all the set rectangles (S115). In the example of FIG. 8 , the average value of the long side lengths of the rectangles calculated in S115 is calculated as the size of the carbon material particles in the dispersion liquid L. The calculated particle size of the carbon material is then used as an index related to the dispersion state of the particles in the dispersion liquid L. Therefore, the particle size of a specific material is calculated as an index related to the dispersion state of the particles in the dispersion liquid L.

[0038] FIG. 9 shows an example of calculating the particle size of a carbon material from an image showing the dispersion state of particles in dispersion liquid L. In the example of FIG. 9, image I1 is acquired as an image showing the dispersion state of particles in dispersion liquid L. Carbon material particles C1, C2, and C3 are detected in image I1. In FIG. 9, particles C1 to C3 are indicated by diagonal hatching. Rectangle α1 is set as the smallest rectangle that contains particle C1, rectangle α2 is set as the smallest rectangle that contains particle C2, and rectangle α3 is set as the smallest rectangle that contains particle C3. The average of the length L1 of the long side of rectangle α1, the length L2 of the long side of rectangle α2, and the length L3 of the long side of rectangle α3 is calculated as the particle size of the carbon material in dispersion liquid L, and is used as an index related to the dispersion state of the particles in dispersion liquid L.

[0039] As in the example of FIG. 8, when the particle size of the carbon material in the dispersion L is calculated as the index, the control unit 7 sets a threshold value for the particle size of the carbon material. If the calculated particle size of the carbon material is equal to or greater than the threshold value, the control unit 7 determines that the particles in the dispersion L have aggregated beyond a reference level. On the other hand, if the calculated particle size of the carbon material is smaller than the threshold value, the control unit 7 determines that the aggregation state of the particles in the dispersion L does not exceed the reference level. Even when an index is calculated as in the example of FIG. 8, the control unit 7 rotates and revolves the dispersion blade 5 based on the fact that the particles in the dispersion L have aggregated beyond a reference level. Therefore, when an index is calculated as in the example of FIG. 8, the control unit 7 rotates and revolves the dispersion blade 5 based on the fact that the calculated particle size is equal to or greater than the threshold value, i.e., based on the fact that the particle size of a specific material is equal to or greater than the threshold value.

[0040] In this embodiment, the agitating blade 3 is rotatable about an axis (first axis) R1, and the dispersing blade 5 is disposed on the outer circumferential side of the axis R1 in the internal cavity 8 of the container 2. The dispersing blade 5 is rotatable about an axis (second axis) R2 at a rotation speed faster than the rotation speed of the agitating blade 3, and is revolvable about the axis R1 at a revolution speed slower than the rotation speed of the agitating blade 3. Therefore, the dispersion L can be agitated by the rotation of the agitating blade 3, and the particles that have aggregated in the dispersion L can be redispersed by the rotation and revolution of the dispersing blade 5.

[0041] Furthermore, in this embodiment, the detection unit 6 detects the dispersion state of particles in the dispersion L, and the rotational movement of the agitating blade 3 and the rotational movement and revolution movement of the dispersing blade 5 are appropriately controlled based on the detection result of the detection unit 6. Therefore, the operations of the agitating blade 3 and the dispersing blade 5 are controlled based on the dispersion state of particles in the dispersion L. This makes it possible to appropriately suppress particle settling and a decrease in fluidity in the stored dispersion L, and also makes it possible to appropriately redisperse aggregated particles. Therefore, it is possible to maintain an appropriate dispersion state of particles in the dispersion L.

[0042] Furthermore, in this embodiment, the control unit 7 determines whether or not particles in the dispersion L have aggregated beyond a reference level based on the detection result from the detection unit 6. Then, based on the fact that particles in the dispersion L have aggregated beyond the reference level, the dispersion blades 5 are rotated and revolved. Therefore, in a state in which it is necessary to redisperse the aggregated particles, the dispersion blades 5 rotate and revolve, and the particles are appropriately redispersed in the dispersion L. This allows the particles in the dispersion L to be maintained in an appropriately dispersed state.

[0043] By maintaining the particles in an appropriate dispersed state in the dispersion liquid L, when a product is manufactured using the dispersion liquid L, the yield in a subsequent process using the dispersion liquid L is improved. This enables stable production of products using the dispersion liquid L. Furthermore, by maintaining the particles in an appropriate dispersed state in the dispersion liquid L, deterioration in the performance of products using the dispersion liquid L is effectively prevented. This allows appropriate quality control of products using the dispersion liquid L.

[0044] Furthermore, in this embodiment, the detection of the dispersion state of particles in the dispersion liquid L involves one or more of acquiring an image showing the dispersion state of particles in the dispersion liquid L, measuring the viscosity of the dispersion liquid L, and measuring a parameter showing the mobility of molecules in the dispersion liquid L by pulsed NMR. Therefore, the dispersion state of particles in the dispersion liquid L is appropriately detected. Then, a determination is made based on the appropriately detected detection result, so that it is appropriately determined whether particles in the dispersion liquid L have aggregated beyond a reference level.

[0045] Furthermore, when acquiring an image showing the dispersion state of particles in the dispersion liquid L, the image of the dispersion liquid L is acquired in a state in which the dispersion liquid L is circulating between the internal cavity 8 and the inspection region 33 of the circulation flow path 30, or in a state in which the dispersion liquid L is circulating between the bypass flow path 38 and the inspection region 33 of the circulation flow path 30. In this way, an image showing the dispersion state of particles in the dispersion liquid L is appropriately acquired as a detection result of the dispersion state of particles in the dispersion liquid L.

[0046] Furthermore, when an image showing the dispersion state of particles in the dispersion liquid L is acquired, the control unit 7 calculates the size of the particles in the dispersion liquid L by analyzing the image acquired by the detection unit 6. This allows the size of particles of a specific material, such as the size of particles of a carbon material, to be properly calculated. Therefore, the size of the particles of the specific material is properly calculated as an index related to the dispersion state of the particles in the dispersion liquid L. Then, the control unit 7 causes the dispersion blade 5 to rotate and revolve on its axis based on the properly calculated particle size being equal to or greater than a threshold value. Therefore, when it is necessary to redisperse the aggregated particles, the dispersion blade 5 rotates and revolves, and the particles are properly redispersed in the dispersion liquid L.

[0047] Furthermore, when measuring the viscosity of the dispersion liquid L and when measuring parameters indicating the mobility of molecules in the dispersion liquid L by pulse NMR, the viscosity and the parameters indicating the mobility of molecules are each measured in a state in which the dispersion liquid L is circulating between the bypass flow path 38 and the inspection region 33 of the circulation flow path 30. As a result, the viscosity of the dispersion liquid L and the parameters indicating the mobility of molecules in the dispersion liquid L are each appropriately acquired as detection results of the dispersion state of particles in the dispersion liquid L.

[0048] According to at least one of these embodiments or examples, the agitating blade is rotatable about a first axis in the internal cavity of the container. The dispersing blade is rotatable about a second axis different from the first axis in the internal cavity at a rotation speed greater than the rotation speed of the agitating blade, and the second axis is revolvable about the first axis at a rotation speed less than the rotation speed of the agitating blade. The detection unit is capable of detecting the dispersion state of particles in the stored dispersion, and the control unit is capable of controlling the operation of the agitating blade and dispersing blade based on the detection results. This makes it possible to provide a storage device and storage method that suppresses particle settling and a decrease in fluidity in the stored dispersion, and maintains an appropriate dispersion state of particles.

[0049] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0050] 1...storage device, 2...container, 3...stirring blade, 5...dispersing blade, 6...detection unit, 7...control unit, 25, 26...driving source, 30...circulation flow path, L...dispersion liquid, R1...axis (first axis), R2...axis (second axis).

Claims

1. a container capable of storing a dispersion liquid in an internal cavity; an agitating blade rotatable about a first axis in the internal cavity of the vessel; a dispersion blade that can rotate around a second axis different from the first axis in the internal cavity of the container at a rotation speed greater than the rotation speed of the agitating blade, and the second axis can revolve around the first axis at a rotation speed smaller than the rotation speed of the agitating blade; a detection unit capable of detecting a dispersion state of particles in the dispersion liquid stored in the internal cavity; a control unit capable of controlling the rotation of the stirring blade and the rotation and revolution of the dispersion blade based on the detection result of the detection unit; A storage device for a dispersion liquid, comprising:

2. The storage device of claim 1, wherein the detection unit performs one or more of the following: acquiring an image showing the dispersion state of the particles in the dispersion liquid; measuring the viscosity of the dispersion liquid; and measuring a parameter showing the mobility of molecules in the dispersion liquid using a pulsed NMR method.

3. the control unit calculates the size of the particles in the dispersion liquid by analyzing the image acquired by the detection unit. The storage device of claim 2.

4. the control unit determines whether the particles in the dispersion liquid have aggregated beyond a reference level based on the detection result from the detection unit.

4. A storage device according to any one of claims 1 to 3.

5. storing a dispersion in an interior cavity of a container; Detecting a dispersion state of particles in the dispersion liquid stored in the internal cavity; Controlling the rotation of an agitating blade that is rotatable about a first axis in the internal cavity based on the detection result of the dispersion state of the particles; Based on the detection result of the dispersion state of the particles, controlling the rotation and revolution of a dispersion impeller that can rotate around a second axis different from the first axis in the internal cavity at a rotation speed greater than the rotation speed of the stirring impeller, and that can revolve around the first axis at a revolution speed lower than the rotation speed of the stirring impeller; A method for storing a dispersion liquid, comprising:

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