Defoaming device for paste and production method of paste

Abstract

To provide a defoaming device for a paste that can effectively perform defoaming, and a production method of a paste.SOLUTION: A defoaming device 100 includes each rotary blade 140 rotatable about a rotation axis O1 and defoams a cathode paste 20A supplied into a container 110. The defoaming device 100 includes a collision part 140c that performs defoaming by causing the cathode paste 20A supplied into a container 120 to collide with the rotary blades 140 that rotate about the rotation axis O1. The defoaming device 100 includes a spreading portion 140d that is located below and radially outward of the collision part 140c, and spreads the cathode paste 20A defoamed in the collision part 140c with the gravitational force and the centrifugal force generated by the rotation of the rotary blades 140 to perform defoaming. The defoaming device 100 includes an upper inner wall portion 111b that causes the cathode paste 20A scattered from an outer end portion 140e on the radial outer side of the spreading portion 140d with the centrifugal force generated by the rotation of the rotary blades 140 to collide with an inner wall 111a of the container 110 to perform defoaming.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an apparatus for degassing a paste and a method for producing a paste. [Background technology]

[0002] Patent Document 1 discloses a paste degassing device capable of degassing the paste. This degassing device includes a container to which the paste is supplied, and a rotating plate that can rotate around a rotation axis inside the container, and the rotating plate is circular in plan view. In this degassing device, the paste before degassing is supplied near the center of the rotating plate inside the container. As a result, the paste is first stretched thinly (thinned) on the rotating plate by the centrifugal force caused by the rotation of the rotating plate, and the bubbles contained in the paste are broken and degassed. Next, the paste that has reached the periphery of the rotating plate is scattered radially outward from the periphery of the rotating plate by the centrifugal force and collides with the inner wall of the container. As a result, the bubbles contained in the scattered paste are broken and degassed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-152184 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, as described above, the two-step degassing method of forming a paste thin film on a rotating plate and then colliding the paste with the inner wall of a container has already become a common method, and therefore a paste degassing device and a paste manufacturing method that can more effectively degas the paste are desired.

[0005] The present disclosure has been made in consideration of the above-mentioned current situation, and has an object to provide a paste degassing device capable of effectively degassing a paste, and a method for producing a paste. [Means for solving the problem]

[0006] (1) One aspect of the present disclosure is A rotor that can rotate around a vertical axis of rotation; A container that accommodates the rotating body, In the paste degassing apparatus for degassing the paste supplied into the container, a collision degassing unit that causes the paste supplied into the container to collide with the rotor that rotates around the vertical rotation axis to degas the paste; a spreading / defoaming section located below and radially outward of the collision / defoaming section, which spreads and defoams the paste defoamed in the collision / defoaming section by gravity and centrifugal force due to rotation of the rotor; and an inner wall degassing section which causes the paste to be scattered from the radially outer spreading outer edge portion of the spreading degassing section by centrifugal force caused by rotation of the rotating body, and degassssing the paste by colliding it with the inner wall of the storage container.

[0007] In the above-mentioned defoaming device, first, the paste is defoamed by the collision defoaming section. Specifically, the paste supplied into the container is defoamed by colliding with a rotor rotating around a vertical rotation axis. Next, the paste is defoamed by the spreading defoaming section located below and radially outside the collision defoaming section. Specifically, the paste defoamed by the collision defoaming section is spread by gravity and centrifugal force due to the rotation of the rotor, and defoamed. Furthermore, the paste is defoamed by the inner wall defoaming section. Specifically, the paste scattered from the spreading outer edge part on the radially outer side of the spreading defoaming section by centrifugal force due to the rotation of the rotor is collided with the inner wall of the container, and defoamed. In this way, the paste is defoamed in three stages by the three defoaming sections, so that effective defoaming can be performed.

[0008] (2) Furthermore, in the degassing device of (1), the rotating body may be provided with an extension portion extending radially outward from the rotating shaft, the extension portion having the collision degassing section and the spreading degassing section, and the spreading degassing section may include a spreading curved surface portion that forms a curved surface that increases the area over which the paste spreads.

[0009] In the above-mentioned defoaming device, the extension portion extending radially outward from the rotating shaft has an impingement defoaming portion and a spreading defoaming portion. The spreading defoaming portion includes a spreading curved surface portion that forms a curved surface that increases the area over which the paste spreads. In this way, the spreading curved surface portion can increase the distance of the paste that is spread to the spreading outer edge portion of the spreading defoaming portion. As a result, the speed at which the paste scatters from the spreading outer edge portion toward the inner wall of the storage container can be increased, and the paste that collides with the inner wall of the storage container can be effectively defoamed.

[0010] (3) Furthermore, in the degassing device of (1) or (2), the rotating body may have a receiving section located below the collision degassing section and the spreading degassing section, and rotate while receiving non-collision paste that has not collided with the collision degassing section from the paste supplied into the storage vessel, and the device may further include a second inner wall degassing section that causes the non-collision paste scattered from the receiving outer edge portion radially outside of the receiving section to collide with the inner wall of the storage vessel by centrifugal force generated by the rotation of the receiving section, thereby degassing the non-collision paste.

[0011] In the above-mentioned defoaming device, the receiving section located below the collision defoaming section and the spreading defoaming section rotates while receiving non-collision paste that has not collided with the collision defoaming section among the paste supplied into the container. The non-collision paste is then defoamed by the second inner wall defoaming section. Specifically, the non-collision paste scattered from the receiving outer edge section on the radial outside of the receiving section by the centrifugal force caused by the rotation of the rotor is caused to collide with the inner wall of the container and is defoamed. In this way, the non-collision paste can be effectively defoamed even if the paste does not collide with the collision defoaming section.

[0012] (4) Another aspect of the present disclosure is a paste manufacturing method using a rotor rotatable about a rotation axis and a storage container that houses the rotor to degas a paste supplied into the storage container to produce a degassed paste, the method including: a collision degassing step in which the paste supplied into the storage container is collided with the rotor rotating about the rotation axis to degas the paste; a spreading degassing step in which the paste degassed in the collision degassing step is spread by gravity and centrifugal force due to the rotation of the rotor to degas the paste; and an inner wall degassing step in which the paste scattered from a radially outer edge of the rotor by centrifugal force due to the rotation of the rotor is collided with an inner wall of the storage container to degas the paste.

[0013] In the above-mentioned manufacturing method, first, in the collision defoaming process, the paste supplied into the container is defoamed by colliding with a rotor rotating around the rotation axis. Then, in the spreading defoaming process, the paste defoamed in the collision defoaming section is spread by gravity and centrifugal force due to the rotation of the rotor, and defoamed. Furthermore, in the inner wall defoaming process, the paste scattered from the outer peripheral part of the rotor on the radial outside by centrifugal force due to the rotation of the rotor is collided with the inner wall of the container and defoamed. Thus, the paste is defoamed in three stages by the three defoaming processes, so that effective defoaming can be performed.

[0014] (5) Furthermore, in the manufacturing method of (4), the rotating body may be provided with an extension portion extending radially outward from the rotating shaft, the extension portion having a spreading / degassing section that spreads the paste and degassssing it in the spreading / degassing process, and the spreading / degassing section may include a spreading curved surface portion that forms a curved surface that increases the area over which the paste spreads.

[0015] In the above-mentioned manufacturing method, the extension portion extending radially outward from the rotating shaft has a spreading / defoaming portion that spreads the paste to defoam it in the spreading / defoaming step. The spreading / defoaming portion includes a spreading curved surface portion that forms a curved surface that increases the area over which the paste spreads. In this way, the spreading curved surface portion can increase the distance over which the paste is spread in the spreading / defoaming portion. As a result, the speed at which the paste is scattered from the radially outer outer edge portion of the rotating body toward the inner wall of the storage container can be increased, and the paste that collides with the inner wall of the storage container can be effectively defoamed.

[0016] (6) Furthermore, in the manufacturing method of (4) or (5), the rotating body may have a receiving portion that rotates while receiving non-collision paste that has not collided in the collision degassing step among the paste supplied into the storage container, and the method may further include a second inner wall degassing step in which the non-collision paste that has been scattered from the receiving outer edge portion on the radially outer side of the receiving portion is caused to collide with an inner wall of the storage container by centrifugal force caused by the rotation of the receiving portion, thereby degassing the non-collision paste.

[0017] In the above-mentioned manufacturing method, the receiving part rotates while receiving the non-collision paste that did not collide in the collision degassing step among the pastes supplied into the container. Then, in the second inner wall degassing step, the non-collision paste scattered from the receiving outer edge part on the radial outside of the receiving part is caused to collide with the inner wall of the container by the centrifugal force caused by the rotation of the rotor, and is degassed. In this way, even if the paste does not collide in the collision degassing step, the non-collision paste can be effectively degassed. [Brief description of the drawings]

[0018] [Figure 1] FIG. 2 is a schematic cross-sectional view of a positive electrode plate according to an embodiment. [Diagram 2] FIG. 2 is a schematic cross-sectional view of a degassing device according to an embodiment. [Diagram 3] 3 is a perspective view showing each rotor, a rotary shaft, and a rotary tray of the degassing apparatus shown in FIG. 2. FIG. [Figure 4]4 is a flowchart showing the flow of a method for producing a positive electrode composite paste. [Diagram 5] FIG. 4 is a cross-sectional view of each rotor in a first modified embodiment. [Figure 6] FIG. 11 is a cross-sectional view of each rotor in a second modified embodiment. [Figure 7] FIG. 13 is a perspective view of each rotor in a third modified embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Next, a paste degassing device 100 and a paste manufacturing method according to an embodiment will be described. FIG. 1 shows a schematic cross-sectional view of a positive electrode plate 1. As shown in FIG. 1, the positive electrode plate 1 includes a positive electrode current collector foil 10 and a positive electrode composite layer 20 laminated on the surface of the positive electrode current collector foil 10. The positive electrode current collector foil 10 is made of, for example, aluminum foil. The positive electrode composite layer 20 is formed by applying a positive electrode composite paste 20B (see FIG. 2) containing a positive electrode active material 21, a conductive material 22, a binder 23, and a solvent 24 to the surface of the positive electrode current collector foil 10, drying the paste, and then performing press processing or the like.

[0020] In this embodiment, the positive electrode active material 21 is a lithium transition metal composite oxide particle, specifically, Li(Ni 1 / 3 Mn 1 / 3 Co 1 / 3 )O2 particles are used. Acetylene black is used as the conductive material 22. PVDF is used as the binder 23. NMP (N-methylpyrrolidone) is used as the solvent 24.

[0021] The positive electrode composite paste 20B is produced by degassing the positive electrode paste 20A (see FIG. 2). The positive electrode paste 20A is produced by kneading a solid content such as the positive electrode active material 21 with a solvent 24. The kneaded positive electrode paste 20A usually contains air bubbles. Therefore, if the positive electrode paste 20A containing air bubbles is applied to the surface of the positive electrode current collector foil 10, a part of the film of the applied positive electrode paste 20A (the part where the air bubbles were present) may have holes, which may cause a see-through defect (a defect in which the surface of the positive electrode current collector foil 10 is partially exposed). Therefore, the positive electrode composite paste 20B is produced by degassing the positive electrode paste 20A using the degassing device 100.

[0022] Next, the degassing device 100 will be described with reference to Fig. 2. As shown in Fig. 2, the degassing device 100 includes a container 110, a rotating shaft 120, a motor 130, four rotors 140, and a rotating tray 150, and degasses the positive electrode paste 20A supplied to the container 110 to produce a positive electrode composite paste 20B.

[0023] The container 110 (container) is a sealable reduced pressure tank (reduced pressure container), and the inside of the container 110 is reduced pressure by a vacuum device Vac including a vacuum pump. In this embodiment, the pressure inside the container 110 is set to a range of -80 kPa to -30 kPa, with the atmospheric pressure being the reference pressure of "0". The container 110 includes a cylindrical side wall portion 111, a disk-shaped lid portion 112, and a funnel-shaped lower portion 113, and accommodates each rotor 140. The lid portion 112 closes the opening at the upper end of the side wall portion 111, and has a supply port (not shown) for supplying the positive electrode paste 20A into the container 110. The side wall portion 111 and the lower portion 113 are connected, and an outlet 113a for taking out the degassed positive electrode composite paste 20B is provided at the lower end of the lower portion 113. In this manner, positive electrode paste 20A is supplied into container 110 from the supply port of lid 112 , and degassed positive electrode composite paste 20B is discharged to the outside of container 110 from outlet 113 a of lower portion 113 .

[0024] The rotating shaft 120 is cylindrical and extends long in the vertical direction (up and down direction), and is rotatable around a rotation axis O1 extending in the vertical direction. The rotating shaft 120 has the rotors 140 assembled thereto so as to be integrally rotatable inside the container 110. The upper end of the rotating shaft 120 is assembled to the motor 130. In addition, a rotating tray 150 is assembled to the lower end of the rotating shaft 120 so as to be integrally rotatable.

[0025] The motor 130 is provided on the lid 112 of the container 110, and is configured to rotate the rotating shaft 120 around the rotation axis O1. Therefore, when the motor 130 is driven, the rotating shaft 120 rotates around the rotation axis O1, and the rotor blades 140 and the rotary tray 150 assembled to the rotating shaft 120 also rotate around the rotation axis O1. In this embodiment, the driving of the motor 130 causes the rotating shaft 120, the rotor blades 140, and the rotary tray 150 to rotate at a rotation speed of 1200 rpm.

[0026] As shown in FIG. 3, each rotor 140 (rotor) is made of a rectangular thin plate extending in the axial and radial directions, and is arranged at equal intervals (90 degree intervals) in the circumferential direction around the rotor shaft 120. The rotors 140 are identical in shape and arranged in an upright state. Therefore, each rotor 140 has a rectangular front surface 140a that stands up on the front side in the rotation direction, and a rectangular rear surface 140b that stands up on the rear side in the rotation direction. Hereinafter, the axial direction of the rotor shaft 120 will be referred to simply as the "axial direction" and the radial direction of the rotor shaft 120 will be referred to simply as the "radial direction" with the rotor shaft 120 as the reference.

[0027] In this embodiment, the axial length L1 of each rotor 140 is 1000 mm, the radial length R1 of each rotor 140 is 800 mm, and the thickness T1 of each rotor 140 is 1 mm. Also, the distance D1 (see FIG. 2) from the radial outer end of each rotor 140 to the inner wall 111a of the side wall portion 111 of the container 110 is 200 mm. Also, in this embodiment, each rotor 140 is made of stainless steel. Note that the above-mentioned length L1, length R1, thickness T1, distance D1, and material of each rotor 140 are merely examples and can be changed as appropriate.

[0028] Rotating tray 150 (receiving portion) is formed in a tray shape so that it can receive positive electrode paste 20A supplied into container 110 below each rotor 140. Rotating tray 150 has disk-shaped horizontal portion 151 and inclined portion 152 that is inclined so that the diameter increases toward the top. The upper side of horizontal portion 151 is a horizontal, circular horizontal surface 151a, and the radial outer end of horizontal portion 151 and the lower end of inclined portion 152 are connected.

[0029] Next, a process in which the positive electrode paste 20A is degassed using the degassing device 100 will be described. First, the positive electrode paste 20A is supplied from a supply port (not shown) of the lid 112 of the container 110. In this embodiment, the flow rate of the supplied positive electrode paste 20A is within a range of 0.3 to 3.6 (L / min). In this manner, the positive electrode paste 20A flowing downward from the top of the container 110 collides with the front surface 140a of the rotor 140 rotating at high speed around the rotation axis O1. Here, in FIG. 3, the portion of the front surface 140a of the rotor 140 that collides with the positive electrode paste 20A is shown generally as a collision portion 140c (collision degassing portion).

[0030] As described above, when front surface 140a of rotor 140 rotating at high speed collides with flowing positive electrode paste 20A in the direction of rotation, the pressure inside positive electrode paste 20A that has been collided with rises sharply. This causes bubbles contained in positive electrode paste 20A to break, and positive electrode paste 20A is degassed. Then, positive electrode paste 20A that has collided with collision portion 140c of front surface 140a of rotor 140 rotates at high speed together with rotor 140 while adhering to front surface 140a of rotor 140.

[0031] Thereafter, the positive electrode paste 20A attached to the front surface 140a of the rotor 140 spreads radially outward and downward due to gravity and centrifugal force caused by the high-speed rotation of the rotor 140. That is, the positive electrode paste 20A is thinly spread radially outward and downward due to gravity and centrifugal force caused by the high-speed rotation of the rotor 140. As a result, the positive electrode paste 20A is made low-viscosity and thin-filmed on the front surface 140a of the rotor 140, and degassing of the positive electrode paste 20A is promoted. Here, in FIG. 3, the part of the front surface 140a of the rotor 140 where the positive electrode paste 20A is spread is shown as a spreading part 140d (spreading degassing part). Also in FIG. 3, the area where the positive electrode paste 20A is spread on the front surface 140a of the rotor 140 is shown as a two-dot chain line 20K.

[0032] Thereafter, the positive electrode paste 20A spread by the spreading portion 140d of the rotor 140 reaches the outer end portion 140e (spreading outer edge portion) of the spreading portion 140d on the radially outer side by the centrifugal force caused by the high-speed rotation of the rotor 140. Then, the positive electrode paste 20A that has reached the outer end portion 140e is scattered toward the inner wall 111a of the side wall portion 111 of the container 110 by the centrifugal force caused by the high-speed rotation of the rotor 140, and collides with the inner wall 111a. This collision breaks the bubbles contained in the positive electrode paste 20A, and the positive electrode paste 20A is defoamed. Note that FIG. 2 shows a schematic view of the positive electrode paste 20A scattered from the outer end portion 140e of the rotor 140 colliding with the upper inner wall portion 111b (inner wall defoaming portion) of the inner wall 111a of the container 110.

[0033] As a result, the degassed positive electrode paste 20A flows down along the inner wall 111a of the container 110 toward the outlet 113a of the lower portion 113 of the container 110. As a result, the degassed positive electrode paste 20A is discharged from the outlet 113a to the outside of the degassing apparatus 100 as the positive electrode composite paste 20B.

[0034] Thus, according to the degassing device 100 of this embodiment, first, the positive electrode paste 20A supplied into the container 110 collides with the collision portion 140c (see FIG. 3) of the rotor 140 rotating at high speed around the rotation axis O1, and is degassed. Next, the positive electrode paste 20A that collides with the collision portion 140c spreads in the spreading portion 140d of the rotor 140 located below and radially outward of the collision portion 140c due to gravity and the centrifugal force caused by the high-speed rotation of the rotor 140, and is degassed. Furthermore, the positive electrode paste 20A scattered from the outer end portion 140e of the spreading portion 140d due to the centrifugal force caused by the high-speed rotation of the rotor 140 collides with the inner wall 111a of the side wall portion 111 of the container 110, and is degassed. As described above, in degassing apparatus 100 of the present embodiment, positive electrode paste 20A is degassed in three stages, and therefore degassing can be performed more effectively than in a conventional degassing apparatus that degassssing paste in two stages.

[0035] In addition, the defoaming device 100 of the present embodiment has a high defoaming ability, and therefore can defoam a large amount of the positive electrode paste 20A, compared to a conventional defoaming device that defoams the paste in two stages. Specifically, as described above, the flow rate of the positive electrode paste 20A supplied to the container 110 can be increased to 3.6 (L / min) to defoam a large amount of the positive electrode paste 20A. In addition, the defoaming device 100 of the present embodiment has a high defoaming ability, and therefore can defoam the positive electrode paste 20A without making the pressure inside the container 110 a high vacuum pressure. Specifically, the pressure inside the container 110 can be made a low vacuum pressure, such as -30 kPa, to suppress evaporation of the solvent 24, and can defoam the positive electrode paste 20A.

[0036] However, there is a risk that the positive electrode paste 20A supplied from a supply port (not shown) of the lid 112 of the container 110 will flow down below each of the four rotors 140 rotating at high speed without colliding with any of the rotors 140. Hereinafter, the positive electrode paste 20A supplied to the container 110 that does not collide with the four rotors 140 will be referred to as the "non-collision paste 20A1." Although the non-collision paste 20A1 flows down below the four rotors 140, it is received by the horizontal surface 151a of the horizontal portion 151 of the rotating tray 150.

[0037] As a result, the non-collision paste 20A1 received on the horizontal surface 151a spreads radially outward on the horizontal surface 151a due to the centrifugal force caused by the high-speed rotation of the rotating tray 150. That is, the non-collision paste 20A1 is thinly stretched radially outward by the centrifugal force caused by the high-speed rotation of the rotating tray 150. Therefore, the non-collision paste 20A1 is degassed by being made low-viscosity and thin-filmed on the horizontal surface 151a of the rotating tray 150.

[0038] Thereafter, the non-collision paste 20A1 reaches the outer end portion of the horizontal surface 151a of the rotating tray 150 on the radially outer side by the centrifugal force due to the high-speed rotation of the rotating tray 150, and then moves along the inclined surface 152a of the inclined portion 152, climbing the inclined surface 152a. Then, the non-collision paste 20A1 that reaches the outer end portion 152b (receiving outer edge portion) on the radially outer side of the inclined surface 152a is scattered toward the inner wall 111a of the side wall portion 111 of the container 110 by the centrifugal force due to the high-speed rotation of the rotating tray 150, and collides with the inner wall 111a. Due to this collision, the bubbles contained in the non-collision paste 20A1 are broken, and the non-collision paste 20A1 is defoamed. FIG. 2 shows a schematic diagram of the non-collision paste 20A1 scattered from the outer edge portion 152b of the rotary tray 150 colliding with a lower inner wall portion 111c (second inner wall degassing portion) of the inner wall 111a of the container 110.

[0039] As a result, the degassed non-collision paste 20A1 flows down along the inner wall 111a of the container 110 toward the outlet 113a of the lower portion 113 of the container 110. As a result, the degassed non-collision paste 20A1 is discharged from the outlet 113a to the outside of the degassing apparatus 100 as the positive electrode composite paste 20B.

[0040] Here, even if a portion of the positive electrode paste 20A supplied into the container 110 collides with the rotor 140 rotating at high speed, it may not scatter from the outer end portion 140e of the rotor 140 toward the inner wall 111a, but may fall downward from the rotor 140 due to gravity. Even in this case, the positive electrode paste 20A falling downward from the rotor 140 is received by the rotating tray 150 and is degassed in the same manner as the non-collision paste 20A1 described above.

[0041] Next, a manufacturing method of the positive electrode composite paste 20B according to this embodiment will be described. FIG. 4 is a flowchart showing the flow of the manufacturing method of the positive electrode composite paste 20B. First, in step S1 (positive electrode paste supply step), the positive electrode paste 20A manufactured by kneading the solid content such as the positive electrode active material 21 and the solvent 24 is supplied from a supply port (not shown) of the lid portion 112 of the container 110. At this time, the positive electrode paste 20A is supplied to a portion of each rotor 140 that is as close as possible to the inner side in the radial direction (the rotating shaft 120 side). This is because the distance of the positive electrode paste 20A spread radially outward on the rotor 140 can be made as long as possible, and degassing of the thinly spread positive electrode paste 20A can be promoted. In addition, the longer the distance of the positive electrode paste 20A spread radially outward, the faster the speed of the positive electrode paste 20A scattering from the outer end portion 140e of the rotor 140 toward the inner wall 111a of the container 110. This is because the energy of scattered positive electrode paste 20A when it collides with inner wall 111a of container 110 is increased, and degassing of the colliding positive electrode paste 20A can be promoted.

[0042] Next, in step S2 (impingement degassing step), positive electrode paste 20A supplied into container 110 is collided in the direction of rotation with front surface 140a of rotor 140 rotating at high speed. As a result, bubbles contained in the collided positive electrode paste 20A are broken, and positive electrode paste 20A is degassed. In this way, positive electrode paste 20A that has collided with front surface 140a of rotor 140 rotating at high speed rotates at high speed together with rotor 140 while adhering to front surface 140a of rotor 140.

[0043] Next, in step S3 (spreading and degassing step), positive electrode paste 20A attached to front surface 140a of rotor 140 is spread radially outward and downward by gravity and centrifugal force due to high-speed rotation of rotor 140. As a result, positive electrode paste 20A is made low-viscosity and thin-filmed on front surface 140a of rotor 140, accelerating degassing of positive electrode paste 20A. Then, positive electrode paste 20A spread on front surface 140a of rotor 140 reaches outer end portion 140e of rotor 140 by centrifugal force due to high-speed rotation of rotor 140.

[0044] Next, in step S4 (inner wall degassing step), positive electrode paste 20A that has reached outer end portion 140e of rotor 140 is scattered toward inner wall 111a of container 110 by centrifugal force due to high speed rotation of rotor 140, and collides with inner wall 111a of container 110. This collision breaks air bubbles contained in positive electrode paste 20A, and positive electrode paste 20A is degassed. Positive electrode paste 20A that has collided with inner wall 111a of container 110 flows down along inner wall 111a of container 110 toward outlet 113a of lower portion 113 of container 110.

[0045] Next, in step S5 (second inner wall degassing process), the rotating tray 150 rotating at high speed below each rotor 140 receives the non-collision paste 20A1 that has not collided with each rotor 140. The non-collision paste 20A1 received by the rotating tray 150 is spread radially outward on the horizontal surface 151a of the rotating tray 150 by centrifugal force due to the high speed rotation of the rotating tray 150. As a result, the non-collision paste 20A1 is reduced in viscosity and thinned on the horizontal surface 151a of the rotating tray 150, and is degassed.

[0046] Thereafter, the non-collision paste 20A1 reaches the outer edge portion 152b of the inclined surface 152a of the rotating tray 150 by the centrifugal force due to the high speed rotation of the rotating tray 150, and then scatters toward the inner wall 111a of the side wall portion 111 of the container 110 and collides with the inner wall 111a. This collision breaks the air bubbles contained in the non-collision paste 20A1, and the non-collision paste 20A1 is degassed. The non-collision paste 20A1 that has collided with the inner wall 111a of the container 110 flows down along the inner wall 111a of the container 110 toward the outlet 113a of the lower portion 113 of the container 110.

[0047] In the above, step S5 (second inner wall degassing process) has been described as a process executed after step S4 (inner wall degassing process). However, step S5 (second inner wall degassing process) is a process executed in parallel with step S2 (impingement degassing process), step S3 (spreading degassing process), and step S4 (inner wall degassing process), and is not necessarily a process executed after step S4 (inner wall degassing process).

[0048] Next, in step S6 (positive electrode composite paste discharge step), the degassed positive electrode paste 20A and non-collision paste 20A1 are discharged as positive electrode composite paste 20B to the outside of degassing apparatus 100 from outlet 113a of lower portion 113 of container 110. In this manner, positive electrode composite paste 20B is produced.

[0049] As described above, according to the manufacturing method of the positive electrode composite paste 20B according to the present embodiment, the positive electrode paste 20A is degassed in three stages by the three degassing steps of step S2 (impingement degassing step), step S3 (spreading degassing step), and step S4 (inner wall degassing step). Therefore, compared to the conventional manufacturing method in which the paste is degassed in two stages to manufacture a degassed paste, degassing can be performed more effectively.

[0050] Furthermore, according to the manufacturing method of the positive electrode composite paste 20B according to this embodiment, in step S5 (second inner wall degassing step), the rotary tray 150 receives the non-collision paste 20A1 that has not collided with each rotor 140. Then, the centrifugal force caused by the rotation of the rotary tray 150 causes the non-collision paste 20A1 scattered from the outer edge portion 152b of the rotary tray 150 to collide with the inner wall 111a of the container 110 and is degassed. In this way, even if the positive electrode paste 20A does not collide with each rotor 140 in step S2 (collision degassing step), the non-collision paste 20A1 can be effectively degassed.

[0051] Next, the first modified embodiment will be described with reference to FIG. 5. FIG. 5 shows a cross-sectional view of each rotor 240 in the first modified embodiment when viewed from above. In the first modified embodiment, the shape of each rotor 240 is different from the shape of each rotor 140 in the embodiment, and the other points are the same as those in the embodiment. As shown in FIG. 5, each rotor 240 (extension portion) does not extend radially outward in a straight line, unlike each rotor 140 in the embodiment, but extends radially outward in a curved line. However, each rotor 240 is arranged in an upright state like each rotor 140 in the embodiment, and differs from each rotor 140 in the embodiment only in that it extends radially outward in a curved line.

[0052] In each rotor 240, a curved front curved surface 240a is formed on the front side in the rotation direction, and a curved rear curved surface 240b is formed on the rear side in the rotation direction. As shown in FIG. 5, each front curved surface 240a is curved such that a central portion 240a1, which is the center side in the radial direction, is located on the rear side in the rotation direction, while an outer end portion 240a2, which is the outer end in the radial direction, is located on the front side in the rotation direction. Thus, each front curved surface 240a is not flat like the front surface 140a (see FIG. 3) of the embodiment, and can be said to be a curved surface (spreading curved surface portion) that increases the area over which the positive electrode paste 20A spreads after the positive electrode paste 20A collides.

[0053] In the first modified embodiment, the positive electrode paste 20A supplied into the container 110 collides with the front curved surface 240a of the rotor 240 rotating at high speed, and is degassed. Next, the positive electrode paste 20A that collides with the front curved surface 240a spreads downward and radially outward along the front curved surface 240a by gravity and centrifugal force due to the high speed rotation of the rotor 240, and is degassed. Next, the positive electrode paste 20A scattered from the outer end portion 240a2 of the front curved surface 240a by the centrifugal force due to the high speed rotation of the rotor 240 collides with the inner wall 111a of the container 110, and is degassed.

[0054] Here, in the first modified embodiment, when the positive electrode paste 20A spreads along the front curved surface 240a, the positive electrode paste 20A does not spread in a straight line radially outward, but spreads in a curved line radially outward. Therefore, the distance of the positive electrode paste 20A spread to the outer end portion 240a2 along the curved front curved surface 240a can be increased. This makes it possible to increase the speed of the positive electrode paste 20A scattering from the outer end portion 240a2 of the front curved surface 240a toward the inner wall 111a of the container 110. As a result, the energy when the scattered positive electrode paste 20A collides with the inner wall 111a of the container 110 is increased, and the degassing of the collided positive electrode paste 20A can be promoted more than in the embodiment.

[0055] Next, the second modified embodiment will be described with reference to Fig. 6. Fig. 6 shows a cross-sectional view of each rotor 340 in the second modified embodiment when viewed from above. In the second modified embodiment, the shape of each rotor 340 is different from the shape of each rotor 240 in the first modified embodiment, and other points are the same as those of the first modified embodiment. As shown in Fig. 6, each rotor 340 (extension portion) does not extend radially outward in a straight line, but extends radially outward in a curved line.

[0056] Each rotor 340 has a curved front curved surface 340a that stands on the front side in the rotation direction, and a curved rear curved surface 340b that stands on the rear side in the rotation direction. As shown in FIG. 6, each front curved surface 340a is curved such that a central portion 340a1, which is the center side in the radial direction, is located on the front side in the rotation direction, while an outer end portion 340a2, which is the outer end in the radial direction, is located on the rear side in the rotation direction. Thus, each front curved surface 340a is not flat like the front surface 140a (see FIG. 3) of the embodiment, and can be said to be a curved surface (spreading curved surface portion) that increases the area over which the positive electrode paste 20A spreads after the positive electrode paste 20A collides with the positive electrode paste 20A.

[0057] In the second modified embodiment, as in the first modified embodiment, when the positive electrode paste 20A spreads along the front curved surface 340a, the positive electrode paste 20A spreads in a curved shape radially outward. Therefore, the distance of the positive electrode paste 20A spread to the outer end portion 340a2 along the curved front curved surface 340a can be increased. This makes it possible to increase the speed of the positive electrode paste 20A scattering from the outer end portion 340a2 of the front curved surface 340a toward the inner wall 111a of the container 110. As a result, the energy when the scattered positive electrode paste 20A collides with the inner wall 111a of the container 110 becomes larger, and degassing of the collided positive electrode paste 20A can be promoted more than in the embodiment.

[0058] Here, the rotor 240 of the first modified embodiment shown in Fig. 5 is compared with the rotor 340 of the second modified embodiment shown in Fig. 6. As shown in Fig. 5, in the front curved surface 240a of the rotor 240 of the first modified embodiment, the central portion 240a1 is located on the rear side in the rotation direction, whereas the outer end portion 240a2 is located on the front side in the rotation direction. Therefore, the positive electrode paste 240A that collides with the front curved surface 240a is likely to reach the outer end portion 240a2 along the central portion 240a1 due to the centrifugal force caused by the rotation of the rotor 340.

[0059] In contrast, in the front curved surface 340a of the rotor 340 of the second modified embodiment, the central portion 340a1 is located at the front side in the direction of rotation, while the outer end portion 340a2 is located at the rear side in the direction of rotation. Therefore, the positive electrode paste 20A that collides with the front curved surface 340a is scattered radially outward from the central portion 340a1 due to the centrifugal force caused by the rotation of the rotor 340, and may not reach the outer end portion 340a2 along the central portion 340a1. As a result, the rotor 240 of the first modified embodiment is advantageous over the rotor 340 of the second modified embodiment in that the positive electrode paste 20A scattered from the outer end portion 240a2 of the front curved surface 240a can be easily caused to collide with the inner wall 111a of the container 110.

[0060] Next, the third modified embodiment will be described with reference to FIG. 7. FIG. 7 shows a perspective view of each rotor 440 in the third modified embodiment. In the third modified embodiment, the shape and number of each rotor 440 are different from those of each rotor 140 in the embodiment, and the other points are the same as those in the embodiment. In the third modified embodiment, as shown in FIG. 7, two spiral rotors 440 are assembled to the rotating shaft 120. In each rotor 440 (extension portion), a front spiral surface 440a is formed on the front side in the rotation direction, and a rear spiral surface 440b is formed on the rear side in the rotation direction. Thus, each front spiral surface 440a is not flat like the front surface 140a (see FIG. 3) in the embodiment, and can be said to be a curved surface (spreading curved surface portion) that increases the area over which the positive electrode paste 20A spreads after the positive electrode paste 20A collides.

[0061] In the third modified embodiment, after the positive electrode paste 20A supplied into the container 110 collides with the front spiral surface 440a of the rotor 440 rotating at high speed, the collided positive electrode paste 20A spreads downward and radially outward in a spiral shape along the front spiral surface 440a due to gravity and centrifugal force caused by the high speed rotation of the rotor 440. In other words, since the positive electrode paste 20A spreads downward while rotating along the front spiral surface 440a, the distance of the positive electrode paste 20A spread to the radial outer end of the front spiral surface 440a can be increased. This makes it possible to increase the speed at which the positive electrode paste 20A scatters from the radial outer end of the front spiral surface 440a toward the inner wall 111a of the container 110. As a result, the energy when the scattered positive electrode paste 20A collides with the inner wall 111a of the container 110 is increased, and degassing of the collided positive electrode paste 20A can be promoted more than in the embodiment.

[0062] In the above, the present disclosure has been described in accordance with the embodiments and various modified forms. However, the present disclosure is not limited to the above-mentioned embodiments and various modified forms, and it goes without saying that the present disclosure can be appropriately modified and applied without departing from the spirit of the present disclosure.

[0063] In the embodiment and each modified embodiment, a case has been described in which positive electrode paste 20A is degassed to produce degassed positive electrode composite paste 20B. However, the paste produced by degassing is not limited to positive electrode composite paste 20B, and for example, a negative electrode paste may be degassed to produce a degassed negative electrode composite paste.

[0064] In the embodiment, the first modified embodiment, and the second modified embodiment, the number of rotors 140, 240, and 340 is four, and in the third modified embodiment, the number of rotors 440 is two. However, the number of rotors is not limited to two or four, and may be one, three, five or more. However, in order to make it easier for the positive electrode paste 20A supplied to the container 110 to collide with the rotor (rotating body), in other words, to prevent the positive electrode paste 20A supplied to the container 110 from falling directly below the rotor without colliding with the rotor, it is preferable that there are multiple rotors.

[0065] In the embodiment, as shown in Fig. 3, the axial length L1 of the rotor 140 is 1000 mm, and the radial length R1 of the rotor 140 is 800 mm. However, the axial length L1 of the rotor 140 and the radial length R1 of the rotor 140 can be changed as appropriate. However, in order to make it easier for the positive electrode paste 20A supplied to the container 110 to collide with the rotor 140, it is preferable that the axial length L1 of the rotor 140 is longer than the radial length R1 of the rotor 140.

[0066] In the embodiment, each rotor 140 (rotating body) is rotatable around a rotation axis O1 extending in the vertical direction. However, the rotating body may be rotatable around a rotation axis extending in a direction other than the vertical direction. For example, the rotating body may be rotatable around a rotation axis extending diagonally upward or around a rotation axis extending in the horizontal direction. [Explanation of symbols]

[0067] 20A Positive Paste 20A1 Non-collision paste 20B Positive electrode mixture paste 100 Deaerator 110 Container 111a Interior wall 111b Upper inner wall part 111c Lower inner wall part 120 Rotating Shaft 140, 240, 340, 440 rotor blades 140c Collision part 140d extension part 140e outer end part 150 Rotating tray 152b Outer end part 240a, 340a Front curved surface 440a Anterior spiral surface O1 Rotational Axis

Claims

1. A rotor that can rotate around a vertical axis of rotation; A container that accommodates the rotating body, In the paste degassing apparatus for degassing the paste supplied into the container, a collision degassing unit that causes the paste supplied into the container to collide with the rotor that rotates around the vertical rotation axis to degas the paste; a spreading / defoaming section located below and radially outside the collision / defoaming section, which spreads and defoams the paste defoamed in the collision / defoaming section by gravity and centrifugal force due to rotation of the rotor; and an inner wall degassing section that causes the paste to be scattered from the radially outer spreading outer edge portion of the spreading degassing section by centrifugal force caused by rotation of the rotor, and degasssing the paste by colliding it with an inner wall of the container.

2. The paste degassing apparatus according to claim 1, The rotor includes an extension portion extending radially outward from the rotary shaft, The extension portion has the collision degassing portion and the spreading degassing portion, The spreading and degassing section is a paste degassing device including a spreading curved surface portion that forms a curved surface that increases the area over which the paste spreads.

3. The paste degassing apparatus according to claim 1 or 2, The rotating body is a receiving section that is located below the collision degassing section and the spreading degassing section and rotates while receiving non-collision paste that has not collided with the collision degassing section out of the paste supplied into the storage container, The paste degassing device further includes a second inner wall degassing section which causes the non-collision paste scattered from the radially outer receiving outer edge portion of the receiving section to collide with the inner wall of the container by centrifugal force caused by rotation of the receiving section, thereby degassing the paste.

4. A rotor that can rotate around a rotation axis; A container for housing the rotating body, A method for producing a degassed paste by degassing the paste supplied into the container, comprising: a collision degassing process in which the paste supplied into the container is collided with the rotor rotating around the rotation axis to degas the paste; a spreading and degassing step in which the paste degassed in the collision degassing step is spread by gravity and centrifugal force due to the rotation of the rotor to degas the paste; and an inner wall degassing process in which the paste scattered from the radially outer end portion of the rotating body is collided with an inner wall of the container by centrifugal force caused by rotation of the rotating body, thereby degassing the paste.

5. The method for producing a paste according to claim 4, The rotor includes an extension portion extending radially outward from the rotary shaft, The extension portion has a spreading / defoaming portion that spreads the paste and defoams it in the spreading / defoaming step, The spreading and degassing section includes a spreading curved surface portion that forms a curved surface that increases the area over which the paste spreads.

6. The method for producing a paste according to claim 4 or 5, the rotating body has a receiving portion that rotates while receiving non-collision paste that has not collided in the collision degassing step among the paste supplied into the storage container, The method for producing a paste further includes a second inner wall degassing process in which the non-collision paste scattered from the radially outer receiving outer edge portion of the receiving portion is collided with the inner wall of the storage container by centrifugal force caused by rotation of the receiving portion, thereby degassing the non-collision paste.

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