Manufacturing method and manufacturing apparatus that includes blades having inclined surfaces for manufacturing a granulated body

A manufacturing method for a granulated body includes supplying powder agitated by a dry agitator to a wet agitator, and agitating the powder supplied from the dry agitator with a liquid component in the wet agitator by rotating blades that have inclined surfaces, so as to form a granulated body. The blades are rotated when the powder is supplied to the wet agitator from the dry agitator. The dry agitator agitates the powder in a dry state, and the wet agitator is positioned below the dry agitator. The wet agitator includes an agitation chamber and the blades rotating around a center axis orthogonal to a direction in which the powder is supplied.

INCORPORATION BY REFERENCE

The disclosure of Japanese Patent Application No. 2017-175045 filed on Sep. 12, 2017 including the specification, drawings and abstract is incorporated herein by reference in its entirety.

BACKGROUND

1. Technical Field

The disclosure relates to a method and an apparatus for manufacturing a granulated body made by granulating powder and a liquid component.

2. Description of Related Art

A granulated body in a granulated state is made by mixing powder and a liquid component with a compounding ratio in which the liquid component is less than that in what is known as paste. A technology described in Japanese Unexamined Patent Application Publication No. 2017-104784 (JP 2017-104784 A) is an example. With the technology described in the literature, as shown in FIG. 1, a “dry mixer 1” and a “wet mixer 2” are used. In the “dry mixer 1”, powder is agitated and mixed without a liquid component, and then agitated with a solvent in the “wet mixer 2”. Thus, a granulated body is obtained. The granulated body is formed into a “granulated body sheet 35” by an “A roll 41” and a “B roll 42”.

SUMMARY

However, in the related art, there is a following problem: powder leaks when the powder is transferred from the “dry mixer 1” to the “wet mixer 2”. Therefore, a solid content ratio in a completed granulated body becomes slightly lower than a target ratio. Of course, it is possible to adjust the solid content ratio appropriately by reducing supply of the liquid component to the “wet mixer 2” by an amount of the powder leaked. However, this still results in a lower yield. The leakage of the powder happens while the powder is transferred because airflow is generated against a flow of the powder when the powder is transferred. This is because, as the powder enters the “wet mixer 2”, air is pushed out from the “wet mixer 2”.

The disclosure provides a manufacturing method and a manufacturing apparatus for a granulated body, the manufacturing method and the manufacturing apparatus restrain powder leakage when the powder is transferred from a dry agitator to a wet agitator.

A manufacturing method for a granulated body according to a first aspect of the disclosure includes supplying powder that is agitated in a dry agitator to a wet agitator, and agitating the powder supplied from the dry agitator with a liquid component in the wet agitator by rotation of blades so as to form a granulated body. The blades are rotated when the powder is supplied to the wet agitator from the dry agitator, the dry agitator agitates the powder in a dry state, and the wet agitator is positioned perpendicularly below the dry agitator. The wet agitator includes an agitation chamber and the blades that rotate inside the agitation chamber around a center axis orthogonal to a direction in which the powder is supplied. The blades include a first blade in a region on a first end portion side of the agitation chamber, and a second blade in a region on a second end portion side of the agitation chamber, the second end portion side being positioned across the agitation chamber from the first end portion side in a direction along the center axis. A first surface of the first blade becomes a front side as the first blade rotates around the center axis the first surface includes a first inclined surface directed towards the first end portion side from the second end portion side, and a second surface of the second blade becomes a front side as the second blade rotates around the center axis the second surface includes a second inclined surface directed towards the second end portion side from the first end portion side.

In the manufacturing method for the granulated body according to the aspect, the granulated body is manufactured in the dry agitation process in which powder is agitated in the dry agitator in a dry state, and thereafter in the wet agitation process in which the powder is agitated with the liquid component in the wet agitator by rotation of the blades. Between the dry agitation process and the wet agitation process, a transfer process is carried out. In the transfer process, the powder after the dry agitation process is supplied to the wet agitator that is disposed perpendicularly below the dry agitator. The blades are also rotated in the transfer process. Therefore, due to an action of the inclined surfaces on the front sides of the blades, airflow is generated in a direction from the first end portion side to the second end portion side, and in a direction from the second end portion side to the first end portion side. Therefore, due to suction by the airflow in the direction from the first end portion side to the second end portion side and in the direction from the second end portion side to the first end portion side, blowing-back of air from the wet agitator towards the dry agitator is reduced. Thus, leakage of the powder is reduced. The term “orthogonal” herein means not only “orthogonal” in a strict sense but also “orthogonal” within a range of common technical knowledge.

In the manufacturing method for the granulated body according to the first aspect, the agitation chamber may have a cylindrical shape, and the center axis may be parallel to the horizontal direction and coincide with a center axis of the cylindrical shape.

In the manufacturing method for the granulated body according to the first aspect, the agitation chamber may include a surface in the region on the first end portion side and a surface in the region on the second end portion side. a first exhaust port is provided in the surface in the region on the first end portion side, and a second exhaust port is provided in the surface in the region on the second end portion side. The first and second exhaust ports function as exits for the airflow. Therefore, blowing-back of air from the wet agitator to the dry agitator is reduced more favorably, and leakage of the powder is reduced further.

In the manufacturing method for the granulated body according to the first aspect, rotational speed of the blades may be 100 rpm or lower, or may even be 60 rpm or lower when the powder is supplied form the dry agitator. When the rotational speed is too high, airflow is generated in a centrifugal direction inside the wet agitator, and an effect of the airflow generated by the inclined surfaces is canceled.

In the manufacturing method for the granulated body according to the first aspect, a first transfer port may be open in a side surface of the dry agitator, a second transfer port may be open in a side surface of the wet agitator, and the first transfer port and the second transfer port may communicate with each other. A shutter may be provided between the side surface of the dry agitator and the side surface of wet agitator. The shutter may open and close the first transfer port and the second transfer port. The blades may be rotated when the shutter is closed

A manufacturing apparatus for a granulated body according to a second aspect of the disclosure includes a dry agitator configured to agitate powder in a dry state, and a wet agitator that is positioned perpendicularly below the dry agitator and configured to agitate the powder with a liquid component. The wet agitator includes an agitation chamber and blades configured to rotate around a center axis that is parallel to a horizontal direction inside the agitation chamber, and the blades include a first blade in a region on a first end portion side of the agitation chamber, and a second blade in a region on a second end portion side of the agitation chamber, the second end portion side being positioned across the agitation chamber from the first end portion side in a direction along the center axis. A first surface of the first blade becomes a front side as the first blade rotates around the center axis, the first surface includes a first inclined surface configured to direct towards the first end portion side from the second end portion side, and a second surface of the second blade becomes a front side as the second blade rotates around the center axis, the second surface includes a second inclined surface configured to direct towards the second end portion side from the first end portion side. With the manufacturing apparatus, it is possible to carry out the manufacturing method for the granulated body according to the first aspect. The term “horizontal” herein means not only “horizontal” in a strict sense, but also “horizontal” within a range of common technical knowledge.

In the manufacturing apparatus for the granulated body according to the second aspect, the agitation chamber may have a cylindrical shape, and the center axis may coincide with a center axis of the cylindrical shape.

In the manufacturing apparatus for the granulated body according to the second aspect, an angle of inclination of the first inclined surface from a vertical plane with respect to the center axis may be in a range from 30° to 60°, and an angle of inclination of the second inclined surface from the vertical plane with respect to the center axis may be in the range from 30° to 60°. When the angles of inclination of the first inclined surfaces are within the range, airflow is generated by the first inclined surfaces efficiently in a direction from the second end portion side to the first end portion side when the blades are rotated. When the angles of inclination of the second inclined surfaces are within the range, airflow is generated by the second inclined surfaces efficiently in a direction from the first end portion side to the second end portion side when the blades are rotated.

In the manufacturing apparatus for the granulated body according to the aspect, the agitation chamber may include a surface in the region on the first end portion side and a surface in the region on the second end portion side. A first exhaust port may be provided in the surface in the region on the first end portion side, and a second exhaust port may be provided in the surface in the region on the second end portion side. This is because the exhaust ports function as exits for the airflows.

The manufacturing apparatus for the granulated body according to the second aspect may include a rotation control part configured to rotate the blades when the powder is supplied to the wet agitator from the dry agitator and when the wet agitator agitates the powder supplied from the dry agitator with the liquid component so as to form the granulated body. Thus, it is possible to carry out the manufacturing method for the granulated body automatically.

In the manufacturing apparatus for the granulated body according to the second aspect, a first transfer port may be open in a side surface of the dry agitator, and a second transfer port may be open in a side surface of the wet agitator. Further, a shutter may be provided between the side surface of the dry agitator and the side surface of the wet agitator. The shutter may be configured to open and close the first transfer port and the second transfer port. The manufacturing apparatus may include a rotation control part configured to rotate the blades when the shutter is closed.

The first exhaust port may be positioned within a range of a circle defined by the cylindrical shape on the surface in the region on the first end portion side, the range excluding 20% on a lower side in a vertical upper-lower direction, and also within a range of the circle excluding 20% on an upper side in the vertical upper-lower direction. The second exhaust port may be positioned within a range of the circle on the surface in the region on the second end portion side, the range excluding 20% on a lower side in the vertical upper-lower direction, and also within a range of the circle excluding 20% on an upper side in the vertical upper-lower direction.

With the configuration, the manufacturing method and the manufacturing apparatus for the granulated body are provided, the manufacturing method and the manufacturing apparatus restraining powder leakage when the powder is transferred from the dry agitator to the wet agitator.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment that embodies the disclosure is described in detail with reference to the attached drawings. In the embodiment, the disclosure is embodied as an apparatus and a method suitable for manufacturing a granulated body of active material powder in order to form an electrode active material layer in a battery manufacturing process. A manufacturing apparatus10for the granulated body according to the embodiment is roughly configured as shown inFIG. 1andFIG. 2. As shown in the sectional view inFIG. 1, the manufacturing apparatus10includes a dry agitator3on an upper side and a wet agitator4on a lower side. Further, as seen in a perspective view of a structure11of the manufacturing apparatus10shown inFIG. 2, both the dry agitator3and the wet agitator4have a cylindrical shape and are arranged so that the axis directions of the dry agitator3and the wet agitator4become horizontal.

As shown inFIG. 1, dispersion blades5are provided inside the dry agitator3. The dispersion blades5are mounted on a rotary shaft6. As the rotary shaft6rotates, the dispersion blades5rotate inside the dry agitator3. The rotary shaft6is provided along a center axis of the cylindrical shape of the dry agitator3. Further, a shutter7is provided in an upper side of the dry agitator3. In an upper part of the dry agitator3, a feed port8is open, and the shutter7opens and closes the feed port8.

Rotating blades are also provided inside the wet agitator4. The blades in the wet agitator4are referred to as cutting blades9. The cutting blades9are also mounted on a rotary shaft12and configured to rotate as the rotary shaft12rotates. The rotary shaft12serves as a center axis orthogonal to a direction in which the powder is supplied, and is provided along a center axis of the cylindrical shape of the wet agitator4. Also, inside the wet agitator4, an agitating blade13is provided in addition to the cutting blades9. Although the agitating blade13also rotates axially inside the wet agitator4, the agitating blade13is arranged so as to be separated from the rotary shaft12and rotate along an inner wall14of the wet agitator4. The cutting blades9rotate in a direction opposite to a direction in which the agitating blade13rotates.

In the foregoing configuration, the rotary shaft6and the rotary shaft12receive rotary drive separately from an outside of the structure11. Further, the agitating blade13rotates due to drive from the outside of the structure11, the drive being separate from that for the rotary shaft12. Illustration and description of the drive of the agitating blade13is omitted. A shutter15is provided between the dry agitator3and the wet agitator4. An open transfer port16is formed between the dry agitator3and the wet agitator4, and the shutter15opens and closes the transfer port16. In other words, a first transfer port is open in a side surface of the dry agitator3, and a second transfer port is open in a side surface of the wet agitator4. The shutter15is positioned between the side surface where the first transfer port is located, and the side surface where the second transfer port is located, and is configured to open and close the first transfer port and the second transfer port. Further, on a lower side of the wet agitator4, a shutter17is provided. In a lower portion of the wet agitator4, a discharge port18is formed so as to open, and the shutter17opens and closes the discharge port18.

In the wet agitator4, a liquid discharge nozzle19is also provided. Meanwhile, no liquid discharge nozzle is provided in the dry agitator3.FIG. 2shows only the structure11that is the manufacturing apparatus10without internal components (the rotary shaft6, the dispersion blades5, the rotary shaft12, the cutting blades9, and the agitating blade13) of the dry agitator3and the wet agitator4.

The cutting blades9of the wet agitator4are described further in detail. As shown inFIG. 3, the cutting blades9are distributed over the entire length of the rotary shaft12. This means that the cutting blades9are provided in both a region L on one end portion side (a first end portion side) and a region R on the other end portion side (a second end portion side) in a center axis direction of an agitation chamber20that is a cylindrical internal space of the wet agitator4. The rotary shaft12in which a number of the cutting blades9shown inFIG. 3are provided has a section unit configuration. This means that the rotary shaft12is configured by connecting a plurality of rotary shaft elements21shown inFIG. 4in a longitudinal direction. In the rotary shaft12shown inFIG. 3, each of the regions L, R is made of three of the rotary shaft elements21. In the rotary shaft element21shown inFIG. 4, the eight cutting blades9are formed.

Each of the cutting blades9shown inFIG. 4is a pillar-shaped portion that is formed so as to project radially outwardly from a shaft portion22. However, in each of the cutting blades9, a surface (first surface, second surface) that is on the front side at the time of rotation serves as an inclined surface23. Further description is given with reference toFIG. 5andFIG. 6regarding the cutting blade9in which the inclined surface23is formed.FIG. 5andFIG. 6are views of the cutting blades9seen from top surface sides of the cutting blades9. This means that, in the drawings, the cutting blades9are seen in the radial direction of the rotary shaft12. InFIG. 5andFIG. 6, arrows G show directions in which the cutting blades9advance due to rotation of the rotary shaft12. As shown inFIG. 5andFIG. 6, the inclined surfaces23are positioned on the front side when the cutting blades9move in the direction of arrow G.

The inclined surfaces23of the cutting blades9(first blades) inFIG. 5and the cutting blades9(second blades) inFIG. 6are inclined in the opposite directions to one another. InFIG. 5, the inclined surfaces23(the first inclined surfaces) are inclined to the left (a direction from the second end portion side to the first end portion side), and are referred to as an “L type”. InFIG. 6, the inclined surfaces23(the second inclined surfaces) are inclined to the right (a direction from the first end portion side to the second end portion side), and are referred to as an “R type”. In each of the rotary shaft elements21(seeFIG. 4) shown inFIG. 3, all of the cutting blades9are either the “L type” or the “R type”, and those of the L type and the R type are never mixed. The cutting blades9actually shown inFIG. 4are the L type. In the rotary shaft12and the cutting blades9shown inFIG. 3, the region L portion is made of three of the rotary shaft elements21that are L-type and the region R portion is made of three of the rotary shaft elements21that are R-type.

A circle25illustrated by a broken line in the lid member24shown inFIG. 7is a circle corresponding to the inner wall14of the wet agitator4. A hole26is formed in the center of the circle25. The hole26is used in order to transmit drive to the rotary shaft12shown inFIG. 3. The agitating blade13shown inFIG. 1is also driven through the hole26. In practice, the hole26is closed by drive transmission members for the rotary shaft12and agitating blade13, and is thus in an airtight state. Inside the circle25of the lid member24, an exhaust port27is formed. Even in a state where the end portions of the agitation chamber20are closed by the lid members24, respectively, air is able to move between an inside and an outside of the agitation chamber20through the exhaust port27. The exhaust port27is positioned at a height of almost the middle of the circle25in the upper-lower direction. Further, the exhaust port27is provided at a position separated from the hole26. As a matter of course, both end portions of the agitation chamber20are closed by the lid members24, respectively.

Although not illustrated, the end portions of the dry agitator3are closed by lid members (not shown) almost same as the lid member24shown inFIG. 7, respectively. However, needless to say, the lid members for the dry agitator3have a size that fits the dry agitator3. In each of the lid members for the dry agitator3, it is not necessary to form an exhaust port equivalent to the exhaust port27.

FIG. 8shows a configuration of a control system of the manufacturing apparatus10according to the embodiment. As shown inFIG. 8, the control system is configured around a control part28. A first motor29, a second motor30, a third motor31, and the shutters7,15,17are connected with the control part28. The first motor29is a driving source for the dispersion blades5of the dry agitator3. The second motor30is a driving source for the cutting blades9and the rotary shaft12shown inFIG. 3. The third motor31is a driving source for the wet agitator4and the agitating blade13. The shutters7,15,17are those described earlier. Thus, each part of the manufacturing apparatus10is controlled and operated appropriately. The content of the control is described in detail later. Regarding the shutters7,15,17, a solenoid or an actuator such as hydro-pneumatic equipment is actually interposed between each of the shutters7,15,17and the control part28.

Next, a manufacturing method for a granulated body using the manufacturing apparatus10having the foregoing configuration is described. The manufacturing method for the granulated body according to the embodiment is carried out by two stages of agitation that are dry agitation as the first stage and wet agitation thereafter. As a matter of course, the dry agitation is carried out in the dry agitator3, and the wet agitation is carried out in the wet agitator4.

The dry agitation in the dry agitator3is done only with powder components that are an electrode active material and additives (a conductive material, a binding material, and so on). This means that, in this stage, no liquid component (solvent) is used. This is the meaning of “dry”. In the dry agitation, first, the shutter15is closed and the shutter7is open, and then powder as a raw material is fed into the dry agitator3from the feed port8. Then, the shutter7is closed and the dispersion blades5are rotated by the first motor29. This is the dry agitation. A part of the base powder fed into the dry agitator3is sometimes solidified in an aggregated state. The dry agitation loosens the base powder, and even if a part of the base powder is in the aggregated state, the part is broken up.

Once the dry agitation is finished, the wet agitation is carried out next. Therefore, the shutter17is closed and the shutter15is opened. Thus, the agitated base powder inside the dry agitator3is supplied to the wet agitator4through the transfer port16. As the transfer port16opens, the base powder naturally moves due to its own weight. This is the transfer.

Then, the shutter15is closed again, and the second motor30and the third motor31rotate the cutting blades9and the agitating blade13, respectively. At this time, a solvent is supplied to the wet agitator4from the liquid discharge nozzle19. As described above, using not only the powder components but also the liquid component is the meaning of “wet”. Inside the agitation chamber20of the wet agitator4, the supplied base powder and solvent are agitated by the cutting blades9and the agitating blade13, and form the granulated body. The granulated body is made of the powder and the solvent that are in the granulated state together, and is particles that are way finer than those of the powder in the aggregated state before the dry agitation.

During the wet agitation, the cutting blades9and the agitating blade13have their own roles. The role of the cutting blades9is to cut and micronize particles that are made by the base powder being entangled with the solvent. The role of the agitating blade13is to scoop up the base powder and the solvent accumulated near a bottom portion inside the agitation chamber20so as to make them agitated. As the shutter17opens, the manufactured granulated body is discharged downwardly from the discharge port18by its own weight. By disposing equipment for the next process in the shutter17shown inFIG. 1, the manufactured granulated body is supplied to the next process. An example of the equipment for the next process includes a sheet forming device like “41” and “42” in FIG. 1 of JP 2017-104784 A. Alternatively, the sheet may be formed on a conductive foil. The dry agitation for the next lot may start in the dry agitator3without waiting for the end of the wet agitation in the wet agitator4. Operations of the first motor29, the second motor30, the third motor31, and the shutters7,15,17in each of the processes are instructed by the control part28shown inFIG. 8.

A characteristic of the embodiment is in the stage of the transfer from the dry agitator3to the wet agitator4. In the embodiment, the cutting blades9(the second motor30) are already rotating at the point when the transfer is happening before the wet agitation starts. The purpose of this is to restrain leakage of the base powder at the time of the transfer. If the transfer is carried out without rotating the cutting blades9, leakage happens with the reasons described in the “Summary”. However, in the embodiment, because the cutting blades9are operated during the transfer, leakage is restrained.

Described below are the reasons why leakage is restrained by rotation of the cutting blades9in the embodiment. As describe inFIG. 5andFIG. 6, the inclined surfaces23are formed in the cutting blades9. Then, the inclined surfaces23face outside with respect to the axis direction in each of the regions L, R. Therefore, as the inclined surfaces23advance due to rotation of the cutting blades9(the rotary shaft12) (arrows G inFIG. 5andFIG. 6), air inside the agitation chamber20is pushed outwardly with respect to the axis direction due to inclination of the inclined surfaces23(arrows P, Q inFIG. 5andFIG. 6). Thus, in the entire agitation chamber20, airflow from the center to both ends in the axis direction is formed. In this state, the transfer of the base powder is carried out.

Therefore, the airflow P, Q restrains air from blowing back to the dry agitator3from the wet agitator4. This means that, by opening the transfer port16while rotating the cutting blades9, airflow shown by arrows C inFIG. 9is generated near the transfer port16. To be specific, since the airflow P, Q sucks in air in the periphery due to the Bernoulli's principle, air tends to be sucked in the wet agitator4from the dry agitator3. If the transfer is carried out without rotation of the cutting blades9, airflow that pushes out air is generated as shown by arrows D inFIG. 10as the base powder is transferred. InFIG. 9, the airflow P, Q cancels the pushing-out airflow D and generates the suction airflow C. As a result, inFIG. 9, leakage of the base powder at the time of transfer is restrained.

Further, as described inFIG. 7, the exhaust port27is formed in the lid member24in each of the end portions of the agitation chamber20. In other words, there is the first exhaust port in a surface of the first end portion of the agitation chamber in the center axis direction, and there is the second exhaust port in a surface of the second end portion of the agitation chamber in the center axis direction. The exhaust ports27also contribute to restraint of the base powder leakage because air that reaches the end portions of the agitation chamber20due to the airflow P, Q is able to escape outside from the exhaust ports27. Leakage of the base powder from the exhaust ports27hardly happens, because the exhaust ports27are provided at positions described earlier.

A position near the bottom portion of the agitation chamber20is where the base powder transferred from the dry agitator3is accumulated. Therefore, it is preferred that each of the exhaust ports27is provided at a position in the circle25inFIG. 7within a range that excludes a range of 20% on a lower side in the upper-lower direction. Further, a position near a top portion of the agitation chamber20is extremely close to the transfer port16disposed between the wet agitator4and the dry agitator3. Specifically, the position is close to a falling path of the base powder immediately after the base powder passes the transfer port16. Therefore, it is more preferred that the exhaust port27is provided at a position in the circle25within a range that also excludes a range of 20% on an upper side in the upper-lower direction. In the embodiment, the exhaust port27is provided at a position within the range that satisfies the above.

The agitating blade13may or may not be rotated at the transfer stage. The airflow P, Q caused by the inclined surfaces23is generated not only in the transfer stage, but also during the wet agitation. However, the airflow P, Q does not particularly mean anything at the time of the wet agitation.

Described below are results of tests carried out by the inventors. The tests described here were carried out in order to verify that rotation of the cutting blades9at the time of the transfer is effective for leakage prevention. In the tests, the following was used as an example of the base powder for a negative electrode material for a lithium ion secondary battery.Active material: natural graphiteConductive material: (not used)Binding material: carboxymethyl celluloseComposition ratio: an active material: an binding material=99:1 (weight ratio)

Further, an elevation angle of the inclined surface23of each of the cutting blades9(an angle of the inclined surface23with respect to the advancing direction G inFIG. 5andFIG. 6) was in three levels that are 30° (FIG. 11), 45° (FIG. 12), 60° (FIG. 13). Regarding the direction of inclination of the inclined surfaces23,FIG. 11,FIG. 12, andFIG. 13only show the L type. However, needless to say, there are three-level elevation angles in the R type as well. Further, as a comparative example, the cutting blades9with an elevation angle of 90°, in other words, the cutting blades9without inclined distal end surface were also prepared. The entire cutting blades9in one rotary shaft12had the same angle of inclination (however, as described earlier, the directions of inclination were different between the regions L, R except the case where the angle is 90°).

Conditions of the dry agitation were set as follows.Rotational speed of the dispersion blades5: 1000 rpmRotation time of the dispersion blades5: 20 seconds

Conditions for the transfer operation were set as follows:Opening time of the shutter15: 8 secondsRotational speed of the cutting blades9: three levels of 0 rpm (stop), 60 rpm, and 100 rpmRotation of the agitating blade13: 0 rpm (stop)

Under these conditions, an amount of powder leakage was calculated based on a weight ratio between a feed amount of the base powder to the dry agitator3and an amount of the base powder in the wet agitator4after the transfer operation is ended. The results are shown in Table 1. In Table 1, values in Italic in the columns “rotational speed of cutting blades” and “elevation angle” mean they do not meet the conditions of the disclosure, and that is why they are stated as comparative examples instead of examples. The results are plotted as a graph shown inFIG. 14.

“Comparative Example 1” in Table 1 is a comparative example in which the transfer was carried out without rotating the cutting blades9. As the comparative example in which the rotation is stopped, the test was carried out only for the cutting blades9with the elevation angle of 90°. In the comparative example, an amount of powder leakage was 2.3% that is not a negligible amount.

“Comparative Example 2”, “Example 1”, “Example 2”, and “Example 3” are test examples where rotational speed of the cutting blades9was 60 rpm. When the four test examples are compared to each other, in any of “Example 1”, “Example 2”, and “Example 3” in which elevation angles are provided, an amount of powder leakage is less than that of “Comparative Example 2” where the elevation angle is 90°. In particular, in “Example 1” with the elevation angle of 30°, and “Example 2” with the elevation angle of 45°, the amounts of powder leakage are extremely small.

“Comparative Example 3”, “Example 4”, “Example 5”, and “Example 6” are the test examples where rotational speed of the cutting blades9was 100 rpm. When the four test examples are compared to each other, almost the same trend is observed as that of the case with the rotational speed of 60 rpm. Thus, in any of “Example 4”, “Example 5”, and “Example 6” in which elevation angles are provided, an amount of powder leakage is smaller than that of “Comparative Example 3” with the elevation angle of 90°. In “Example 4” with the elevation angle of 30° and “Example 5” with the elevation angle of 45°, the amounts of powder leakage are far smaller than that of “Comparative Example 3”.

Looking through “Example 1”, “Example 2”, and “Example 3”, and “Example 4”, “Example 5”, and “Example 6”, in any of these examples, the amount of powder leakage is smaller than that of the comparative examples with the same rotational speed of the cutting blades9. Also, when the examples with the same rotational speed of the cutting blades9are compared to each other, the smaller the elevation angle is, the smaller the amount of powder leakage becomes. The reason why a smaller elevation angle produces a more excellent result is considered to be that the inclined surface23becomes wider and generates larger force for pushing air towards the end portions.

Further, compared to the case where the rotational speed of the cutting blades9is 100 rpm, the result is more excellent when the rotational speed of the cutting blades9is 60 rpm that is slightly slower than the fast speed of 100 rpm. When the rotational speed of the cutting blades9is too fast, the effect of the disclosure tends to be reduced. The reason is considered to be that rotation of the cutting blades9itself generates airflow in a centrifugal direction to some extent when the rotational speed of the cutting blades9is too high. However, at 100 rpm, the effect is still recognized even in the case of the most unfavorable “Example 6” in comparison with “Comparative Example 3”, and the result is still better than “Comparative Example 1”.

Accordingly, it is understood that the effect of the disclosure is obtained within a range of the elevation angle of the inclined surface23from 30° to 60°. In particular, it is more preferable when the elevation angle is within a range from 30° to 45°. Also, it is understood that the effect of the disclosure is obtained when the rotational speed of the cutting blades9is at least within a range not exceeding 100 rpm, and the range not exceeding 60 rpm is more favorable.

As described so far, according to the embodiment, it is possible transfer the base powder from the dry agitator3to the wet agitator4while restraining leakage of the base powder. Therefore, it is possible to manufacture the granulated body favorably while the liquid discharge nozzle19adjusts a supply of the solvent to the wet agitator4to a target amount. For example, when the type of the base powder is the one described above, it is considered that water is used as the solvent, and the amount of the base powder to be supplied is equivalent to a solid content ratio of 73% by weight.

As described so far in detail, according to the embodiment, the dry agitator3and the wet agitator4are provided, and the granulated body is manufactured by the wet agitation after the dry agitation. In the manufacturing of the granulated body, when the base powder is transferred from the dry agitator3to the wet agitator4, the airflow P, Q towards the end portions is generated inside the wet agitator4. Thus, at the time of the transfer, air is restrained from blowing back to the dry agitator3from the wet agitator4, thereby reducing leakage of the base powder. In this way, the manufacturing apparatus10and the manufacturing method for the granulated body are realized, the manufacturing apparatus10and the manufacturing method enabling the granulated body having a targeted solid content ratio to be obtained in a favorable fashion.

The embodiment is only an example and does not limit the disclosure at all. Therefore, it is naturally possible to make various improvements and deformations in the disclosure without departing from the gist of the disclosure. For example, the specific configuration of the dry agitator3is optional, and the dry agitation may be carried out with a different configuration from the dispersion blades5. Further, the agitating blade13in the wet agitator4is not essential. When a clearance between distal ends of the cutting blades9and the inner wall14of the agitation chamber20is small enough, the base powder may hardly accumulate at the bottom portion of the agitation chamber20even when the agitating blade13is not provided. Further, the cutting blades9are not limited to those provided outwardly from the rotary shaft12, and may be provided inwardly from a member that rotationally moves along the inner wall14of the agitation chamber20. Also, the total number of the cutting blades9is not particularly limited.

The rotary shaft12and the cutting blades9shown inFIG. 3may not have a configuration that is made of pieces of the rotary shaft elements21shown inFIG. 4. The cutting blades9may be mounted on the integral rotary shaft12, or the rotary shaft12and the cutting blades9may be integrated as a whole. The cutting blades9do not necessarily make a pair as shown inFIG. 5andFIG. 6. Also, a border between the region L and the region R inFIG. 3does not necessarily coincides with the center of the rotary shaft12in the longitudinal direction. Further, one of the rotary shaft elements21shown inFIG. 4may be disposed across the border between the region L and the region R. In this case, in the rotary shaft element21disposed at the position, the cutting blades9on one end side are the L type, and the cutting blades9on the other end side are the R type.

The exhaust port27in the lid member24is not necessarily essential. Even when the exhaust port27is not formed in the lid member24, the airflow P, Q inFIG. 5andFIG. 6is generated, and negative pressure is still generated due to the Bernoulli's principle. Also, when the exhaust port27is provided, the number of the exhaust ports27is not limited to one for each of both sides. More than one exhaust port27may be provided in each of the lid members24. Further, in the embodiment, the exhaust port27is provided at the position separated from the hole26. However, the hole26may also serve as the exhaust port27.

A shutter may be provided in the exhaust port27. In that case, the shutter is open at the transfer stage, and the shutter is closed when the wet agitation is carried out. Because of this, leakage of the base powder from the transfer port16at the transfer stage is prevented more favorably, and, at the same time, leakage of the base powder and the solvent from the exhaust port27at the time of the wet agitation is also prevented. However, even in the configuration where the shutter is not provided and the exhaust port27is left open, leakage of the base powder and the solvent from the exhaust port27is not a big problem. By setting the position of the exhaust port27as described earlier, it is possible to prevent leakage of materials to be agitated from the exhaust port27. Further, by providing a so-called “labyrinth structure” in places that continue from an outer side of the exhaust port27, it is possible to prevent leakage of a solid component and a liquid component while allowing air to escape from the exhaust port27.

Moreover, the inclined surface23may not necessarily be a flat plane. When the inclined surface23is not a flat plane, the elevation angle is different depending on locations within the inclined surface23. In this case, it is determined whether or not the elevation angle is in a preferred range by seeing, for example, whether or not an area of the inclined surface23occupied by a portion where the elevation angle is within the favorable range has a given ratio (for example, 80%) or higher. Alternatively, an average value of the elevation angle in the entire inclined surface23may be used for the determination. Further, with the manufacturing apparatus10for the granulated body according to the embodiment, it is possible to manufacture not only the granulated body of a negative electrode active material, but also a granulated body of a positive electrode active material. Further, it is possible to manufacture a granulated body other than an electrode material for a battery.