JP2015077698A - Kneading machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove lump from obtained kneaded object without adding a piping and a pump between a kneading machine and a coater.SOLUTION: A kneading machine 10 comprises: a tank formed of a tank body 11a storing raw materials including at least an active material, a binder and a solvent and a hood 11b; kneading means 12 for kneading the raw materials in the tank body 11a; and a discharge part 13 for discharging the raw materials after being kneaded in the tank body 11a. The discharge part 13 has a filter 14 for filtering a slurry-state mixture for electrode which passes the discharge part 13.

Description

  The present invention relates to a kneading machine, and more particularly to a kneading machine for producing an electrode mixture for a power storage device.

  Power storage devices such as secondary batteries and capacitors are widely used as power sources because they can be recharged and can be used repeatedly. Conventionally, lithium ion secondary batteries, nickel-hydrogen secondary batteries, and the like are well known as power storage devices mounted on vehicles such as EVs (Electric Vehicles) and PHVs (Plug-in Hybrid Vehicles). In these secondary batteries, an electrode having an active material layer formed by applying a paste-like or slurry-like active material mixture containing an active material on the surface of a metal foil is laminated with a separator interposed therebetween. The electrode assembly is formed by winding or the like, and the electrode assembly is housed in a case.

  Adjustment of a slurry-like electrode active material mixture (hereinafter simply referred to as electrode mixture) includes at least an active material, a binder and a solvent, and kneads a raw material containing a thickener as necessary. The active material, the binder, and the thickener are powders, and the powder and solvent are uniformly mixed to produce a slurry-like active material mixture. A kneading method (kneading) followed by dilution with a solvent is used.

  There are batch and continuous kneading methods. In the continuous type, the raw material is continuously supplied from the introduction port into the casing provided with the stirring body therein, and after being stirred and mixed by the stirring body, is discharged from the discharge port. For example, in Patent Document 1, as a biaxial continuous kneader, two rotating shafts are arranged in a kneading chamber, and powder and liquid charged by a feed screw supported by the rotating shaft are fed from upstream to downstream. Similarly, a structure is described in which powder and liquid are stirred by a barrel (stirring body) supported by a rotating shaft. An example of an electrode manufacturing apparatus including such a kneader is disclosed in Patent Document 2. The electrode manufacturing apparatus of patent document 2 consists of a manufacturing part, a storage part, and a coating part, and each part is connected with the pipe line and the pump. On the other hand, in the batch type, once the kneading of the raw materials is completed in the tank of the kneader, the slurry-like electrode mixture is recovered from the recovery port (discharge port) of the tank. use. As an example of such a batch-type kneader, Patent Document 3 discloses a configuration in which the kneading means can be lifted and lowered together with the lid with respect to the paste in the container.

  When the batch type and the continuous type are compared, the batch type is excellent in traceability. For example, in a continuous kneading machine, the relationship between the powder and liquid materials that are continuously charged and the electrode mixture discharged from the discharge port is confirmed structurally. difficult. Specifically, even when there is a change in the characteristics of the manufactured electrode mixture or the active material layer of the electrode, it is difficult to specify when and which material is charged. For this reason, when importance is attached to quality control at the time of kneading, a batch type is used.

JP 2011-83703 A JP 2011-181465 A JP 2009-22890 A

  In a batch kneader, it is desirable to remove lumps (aggregates of powder) after kneading in order to obtain a higher quality electrode mixture. Patent Document 2 discloses a circulation system that circulates an electrode slurry in a storage unit and a coarse particle removal filter in which the circulation system is arranged. However, the batch-type kneader does not have a pipe for arranging the filter as in Patent Document 2 and a pump for feeding the electrode mixture to the filter.

  The present invention has been made in view of the above problems, and its purpose is a batch type capable of removing lumps without providing a pipe or a pump between the kneading machine and the coating machine. Is to provide a kneading machine.

  A kneading machine that solves the above problems is a kneading machine that produces a kneaded material from a plurality of raw materials, a container that contains the raw materials, a kneading means that kneads the raw materials in the container, and kneading from within the container. A discharge unit capable of discharging an object, and a filter provided in the discharge unit.

  According to this kneading machine, when the raw materials are put into the container, the kneaded product is kneaded by the kneading means. When the kneaded material is discharged (collected) from the discharge portion, the kneaded material is removed by passing through a filter provided in the discharge portion. Therefore, it is possible to remove lumps from the obtained kneaded product without providing piping or a pump between the kneading machine and the coating machine, and without adding a new operation for filtration.

  The kneaded material is an electrode mixture containing at least an active material, a binder, and a solvent as raw materials, and the discharge portion includes opening / closing means disposed on the inner side of the container than the filter, and the opening / closing means includes the raw material when closed. It is preferable to prevent intrusion into the filter. When the raw materials in the container are kneaded by the kneading means, if the raw materials are kneaded in contact with the filter, the raw material powder enters the filter during the kneading. Since the raw material that has entered the filter is not subjected to a shearing action by the kneading means, there is a possibility that the dispersed state of the generated electrode mixture may deteriorate. However, by disposing the opening / closing means inside the container from the filter at the discharge portion, entry of raw materials into the filter is prevented during kneading. Thereby, there is no possibility that the dispersion state of the active material in the slurry-like electrode mixture is deteriorated.

  It is preferable that the container includes a supply port that allows gas to be introduced into the container at an upper part of the container. According to this configuration, when the slurry-like electrode mixture is discharged (recovered) from the discharge portion after the raw materials have been kneaded, the pressurized gas is supplied into the container from the supply port, whereby the filter is provided at the discharge portion. Even if it is arranged, the time required for discharging (collecting) the electrode mixture can be shortened.

  According to the present invention, it is possible to remove lumps from the obtained kneaded product without adding piping or a pump between the kneading machine and the coating machine.

(A) is a partially broken front view of the kneading machine of one Embodiment, (b) is a partial expanded sectional view. The schematic cross section of the state where the kneading means is disposed at the kneading position. (A) is a typical fragmentary sectional view of the state which connected piping at the time of collection | recovery of the electrode mixture, (b) is a schematic fragmentary sectional view of the state which has arrange | positioned the cover in the open position and collect | recovered the electrode mixture. (A) is a typical fragmentary sectional view of another embodiment, (b) is the elements on larger scale. The typical fragmentary sectional view of another embodiment. The typical fragmentary sectional view of another embodiment. The typical fragmentary sectional view of another embodiment.

Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS.
As shown in FIG. 1, the batch-type kneader 10 is basically configured in the same manner as a planetary mixer, and has a bottomed cylindrical tank body 11 a and a top of the tank 11 as containers for containing raw materials. A tank 11 composed of a hooded cylindrical hood 11b covering the opening of the tank body 11a and a kneading means 12 for kneading the raw materials stored in the tank body 11a are provided. The tank body 11a includes a discharge portion 13 that discharges the raw material after being kneaded in the tank body 11a, and the discharge portion 13 is provided with a filter 14 that filters the electrode mixture that passes through the discharge portion 13. Yes. The tank 11 is made of metal such as stainless steel.

  Above the tank 11, a stirring head 15 is provided so as to be movable up and down by a cylinder 16, and the hood 11 b is fixed to the stirring head 15 so as to be movable up and down together with the stirring head 15. The hood 11 b includes a pressurizing port 17 as a supply port that enables introduction of gas into the tank 11. The pressurizing port 17 is configured to be connectable to a pressurized gas supply unit via a pipe. That is, the tank 11 includes a pressurizing port 17 that can be connected to a pressurized gas supply unit that pressurizes the inside of the tank 11.

  The stirring head 15 includes a rotor 18, and the rotor 18 is driven by a drive shaft that is driven by a motor 19 via a speed reducer 20. The rotor 18 includes a planetary gear mechanism, and the kneading means 12 is driven by the rotor 18 in a state of performing planetary gear movement.

  The kneading means 12 can be moved to a stirring position (the state shown in FIG. 2) for stirring in the tank body 11a and a standby position retracted from the tank body 11a by raising and lowering the stirring head 15. The kneading means 12 has a plurality (two in this embodiment) of blades 12a, and the blade 12a is limited to the amount of the object to be stirred in the tank main body 11a with the stirring head 15 moved to the lowest position. First, the stirring object is disposed at a stirring position where stirring is possible. The kneading means 12 is configured to be able to mix powder or knead powder and liquid while performing a planetary motion in the tank body 11a at the stirring position.

  The blade 12a is formed in a triangular frame shape by joining, for example, metal squares such as stainless steel. Further, the blade 12a is disposed so as to have a distance for applying a large shearing force to the raw material between the blade 12a and the inner surface of the bottom wall of the tank body 11a in a state where the kneading means 12 is disposed at the stirring position.

  As shown in FIG.1 (b), the discharge part 13 has the opening part 13a formed in the bottom wall 21 of the tank main body 11a, and the cylinder part 13b protrudingly provided by the outer periphery of the tank main body 11a from the periphery of the opening part 13a. And. A filter 14 is provided on the proximal end side of the cylindrical portion 13b to filter the kneaded raw material that passes through the opening 13a, that is, the electrode mixture (electrode active material mixture).

  The discharge unit 13 is an opening / closing unit for the discharge unit 13 and includes a cover 23 that covers the filter 14. The cover 23 is provided closer to the inside of the tank body 11a than the position where the filter 14 is provided in the opening 13a. The cover 23 has a shielding position shown in FIG. 1B that prevents the raw material existing in the tank main body 11 a from entering the discharge portion 13 and a retreat position that allows the raw material to enter the discharge portion 13. It is provided to be movable.

  More specifically, the bottom wall 21 is provided with an accommodating portion 24 that accommodates the cover 23 so as to be slidable parallel to the bottom surface of the tank body 11a. The cover 23 is formed wider than the diameter of the opening 13a, and a guide groove 25 that allows the movement of the cover 23 is formed in the bottom wall 21 continuously to the end of the accommodating portion 24 near the opening 13a. As shown in FIG. 1 (b), the cover 23 is adapted to be fitted at a position where the tip of the cover 23 faces the accommodating portion 24 of the guide groove 25 in the state where the cover 23 is disposed at the shielding position.

  A groove 24 a that opens to the outer surface side of the bottom wall 21 is formed in the accommodating portion 24. A rod-like operation member 26 is fixed to the cover 23 on the rear end side, on the right end side in FIG. The cover 23 is shown in FIG. 3B where the operator moves the operating member 26 along the groove 24a, and in FIG. 3B where the cover 23 opens the opening 13a. It is moved to the retracted position. A seal member 27 for preventing the raw material stored in the tank body 11a from leaking to the outside from the groove 24a is provided at the end of the storage portion 24 near the opening 13a.

Next, the operation of the kneader 10 configured as described above will be described by taking as an example the production of a positive electrode mixture for a lithium ion battery, which is a secondary battery.
The raw material of the positive electrode mixture is, for example, a positive electrode active material made of a metal composite oxide of lithium and a transition metal, such as a lithium / manganese composite oxide, a lithium / cobalt composite oxide, or a lithium / nickel composite oxide, A conductive agent such as acetylene black, a binder such as polyvinylidene fluoride (PVDF), and a solvent such as N-methylpyrrolidone (NMP) are included.

  When kneading raw materials, as shown in FIG. 1 (a), the hood 11b is placed in the raised position, the tank body 11a is opened, and as shown in FIG. 1 (b), the cover 23 is in the shielding position. The raw material is accommodated (injected) in the tank main body 11a in the arranged state. At this time, it is preferable to add the powder in a state where the liquid (solvent) of the raw materials is placed in the tank body 11a. In addition, since kneading is performed after solid kneading and further kneading by adding a solvent, the amount of the solvent is smaller than the amount of the solvent contained in the electrode mixture 31 when the adjustment is completed.

  Next, the cylinder 16 is driven, and as shown in FIG. 2, the tank 11 is disposed in a state in which the hood 11 b covers the tank body 11 a and the blade 12 a of the kneading means 12 can knead the raw material 30. In this state, the motor 19 is driven and the blade 12a rotates while performing planetary motion, whereby the raw material 30 is kneaded and kneaded. Kneading is performed for a predetermined time set in advance, and the motor 19 is stopped. Then, after the hood 11b is arranged at the open position, the solvent is added, and the hood 11b is arranged again at a position covering the opening, kneading is resumed. Then, the kneading is continued for a predetermined time, and the adjustment of the electrode mixture 31 is completed.

  When the raw material 30 in the tank 11 is kneaded by the kneading means 12, if the raw material 30 is kneaded in contact with the filter 14, the powder or a mixture of the powder and the solvent enters the filter 14 during the kneading. Since the powder or mixture that has entered the filter 14 is not subjected to the shearing action of the blade 12a, the dispersion of the produced positive electrode mixture or the active material layer of the electrode may be deteriorated. However, since the kneading is performed in a state where the cover 23 is disposed at a shielding position that prevents contact between the filter 14 and the raw material 30 being kneaded, a powder or a mixture of the powder and the solvent is mixed with the filter 14 during the kneading. Intrusion into the cathode is avoided, and there is no possibility that the dispersion state of the positive electrode mixture deteriorates.

  When the kneading of the raw material 30 is completed and the adjustment of the slurry-like electrode mixture 31 is completed, the slurry-like electrode mixture 31 in the tank main body 11a is discharged (collected) from the discharge portion 13. First, as shown to Fig.3 (a), the 1st end part of the pipe 28 is connected to the cylinder part 13b. The second end of the pipe 28 is disposed at a position where the electrode mixture 31 is supplied to the active material mixture storage tank of the coating machine. Next, when the operator holds the operating member 26 of the cover 23 and moves the cover 23 to the retracted position, as shown in FIG. 3 (b), the electrode mixture 31 passes from the tank body 11 a through the discharge portion 13. Move into the pipe 28.

  The electrode mixture 31 that moves from the tank body 11 a into the pipe 28 through the discharge portion 13 passes through the filter 14 provided in the discharge portion 13, and the filter 14 causes a dama present in the electrode mixture 31. Is filtered to remove lumps.

  After the cover 23 is moved to the retracted position, pressurized gas is supplied into the tank 11 from the pressure port 17. For example, nitrogen gas or dry air is used as the pressurized gas. Since the discharge part 13 is provided in the bottom wall 21 of the tank main body 11a, when the cover 23 is moved to the retracted position, the electrode mixture 31 moves from the tank main body 11a to the pipe 28 by its own weight. However, the time required to discharge (collect) the electrode mixture 31 can be shortened by supplying the pressurized gas from the pressure port 17 into the tank 11.

  After the collection of the electrode mixture 31 is completed, the supply of the pressurized gas is stopped. Thereafter, the hood 11b is moved to the raised position, and at least the filter 14 is washed. As a result, when collecting the electrode mixture 31, the lumps and the like separated from the electrode mixture 31 passing through the filter 14 and adhering to the filter 14 are removed. 14 functions normally.

According to this embodiment, the following effects can be obtained.
(1) The kneading machine 10 is a batch type kneading machine for producing a kneaded product from a plurality of raw materials. The tank 11 accommodates the raw material 30; the kneading means 12 for kneading the raw material 30 in the tank 11; The discharge part 13 which discharges the raw material 30 after being kneaded inside, and the filter 14 which is provided in the discharge part 13 and filters the electrode mixture 31 which is the raw material 30 after kneading that passes through the discharge part 13. And. According to this configuration, the slurry-like electrode mixture obtained without adding piping and a pump between the kneading machine 10 and the coating machine and without newly adding a work for filtration. The lumps can be removed from 31.

  (2) The kneading machine 10 includes a cover 23 that prevents the filter 14 from contacting the raw material 30 being kneaded. The cover 23 prevents the raw material 30 existing in the tank 11 from entering the discharge unit 13. It is provided so as to be movable between a shielding position where the raw material 30 is moved and a retreat position where the raw material 30 is allowed to enter the discharge portion 13. According to this configuration, the cover 23 is disposed at the shielding position during the kneading of the raw material 30, thereby preventing the powder from entering the filter 14 during the kneading and the dispersed state of the slurry-like electrode mixture 31. There is no risk of deterioration.

  (3) The tank 11 includes a pressurizing port 17 that can be connected to a pressurized gas supply unit that pressurizes the inside of the tank 11. According to this configuration, when the slurry-like electrode mixture 31 is discharged (collected) from the discharge unit 13 after the kneading of the raw material 30, the pressurized gas can be supplied into the tank 11 from the pressure port 17. it can. Thereby, also when the filter 14 is attached to the discharge part 13, the time required for discharge | emission (collection | recovery) of the electrode mixture 31 can be shortened.

  (4) The discharge unit 13 includes an opening 13a formed in the bottom wall 21 of the tank main body 11a, and a cylindrical portion 13b protruding from the periphery of the opening 13a to the outside of the tank main body 11a. Therefore, compared with the case where the opening 13a is formed on the side wall of the tank main body 11a, all the electrode mixture 31 in the tank main body 11a is collected when the kneaded and adjusted electrode mixture 31 is recovered. It becomes easy to collect. Moreover, the dead weight of the electrode mixture 31 can be efficiently used for recovery.

The embodiment is not limited to the above, and may be embodied as follows, for example.
O The discharge part 13 is not restricted to the structure provided in the bottom wall 21 of the tank main body 11a. For example, as shown to Fig.4 (a), (b), you may provide in the side wall 22 of the tank main body 11a. In this case, since the cover 23 is also provided on the side wall, it is necessary to increase the thickness of at least the portion where the cover 23 is provided compared to the case where the cover 23 is not provided. The cover 23 is not a flat plate but a curved plate corresponding to the curvature of the side wall 22. The accommodating portion 24 that accommodates the cover 23 is also formed in a curved shape corresponding to the shape of the cover 23.

  The cover 23 that prevents contact between the filter 14 provided in the discharge unit 13 and the raw material being kneaded is not essential, and the cover 23 may not be provided. When the cover 23 is not provided, the discharge part 13 may be provided on the bottom wall 21 or the discharge part 13 may be provided on the side wall 22 as shown in FIG. When the cover 23 is not provided, as shown in FIG. 5, the filter 14 may be provided near the inner end of the opening 13a or may be provided in the middle of the opening 13a.

  When providing the discharge part 13 in the bottom wall 21, you may form so that the lower end of the opening part 13a may become the same height as the upper surface of the bottom wall 21, as shown in FIG. In this case, even when the amount of the electrode mixture 31 in the tank body 11a is reduced when the electrode mixture 31 is recovered, the electrode mixture 31 can smoothly pass through the opening 13a in the tank body 11a. Is discharged (recovered).

  The shape of the blade 12a constituting the kneading means 12 is not limited to the triangular frame shape, and may be changed as appropriate. For example, as shown in FIG. 7, the shape of the blade 12a may be a shape having a portion parallel to the bottom wall 21 of the tank body 11a and portions extending vertically upward from both ends of the parallel portion. In this case, unlike the case where the shape of the blade 12a is triangular, the powder agglomerates are reduced between the inner surface of the tank body 11a and the blade 12a even in the portion extending parallel to the side wall 22 of the blade 12a during kneading. Effect is obtained.

  In the case where the raw material 30 is put into the tank body 11a, instead of putting the powders of the individual materials into the tank body 11a separately, a mixture of a plurality of powders previously stirred without a solvent may be put in.

  In the case where the raw material 30 is charged into the tank body 11a, the solvent may be charged after the powder is first charged instead of the powder after the solvent is charged. In this case, a plurality of powder materials may be charged into the tank body 11a and stirred with only the powder, and then the solvent may be charged. Alternatively, a part of the powder, for example, a binder, may be put into a kneader in a state of being mixed in advance with a liquid.

  ○ When the inside of the tank 11 is pressurized with pressurized gas at the time of collecting the electrode mixture 31, pressurization is not performed from the beginning of the collection, but is performed during the collection or added at the end of the collection. You may make it perform a pressure.

(Circle) you may make it collect | recover without performing pressurization at the time of collection | recovery of the electrode mixture 31. FIG. In this case, the collection destination needs to exist below the tank body 11a.
The configuration for moving the cover 23 to the shielding position and the retracted position may be a configuration for rotating the cover 23 instead of the configuration for sliding the cover 23 linearly.

O The raw material of the positive electrode mixture as the electrode mixture is not limited to the substances described above, and may be appropriately changed.
○ When preparing a negative electrode mixture as an electrode mixture, raw materials include, for example, an active material such as graphite, a thickener such as carboxycellulose (CMC), and a styrene butadiene block copolymer (SBR). A polymer dispersed in water that can function as a binder and a solvent such as water are included.

  O The raw material of the negative electrode mixture as the electrode mixture is not limited to the substances described above, and may be appropriately changed. For example, the active material for the negative electrode may be a material that can occlude and release lithium ions.

  DESCRIPTION OF SYMBOLS 10 ... Kneading machine, 11 ... Tank, 12 ... Kneading means, 13 ... Discharge part, 14 ... Filter, 17 ... Pressurization port, 23 ... Cover, 30 ... Raw material, 31 ... Electrode mixture.

Claims (4)

A kneader for producing a kneaded product from a plurality of raw materials,
A container for containing the raw materials;
Kneading means for kneading the raw materials in the container;
A discharge part capable of discharging the kneaded material from the container;
A kneading machine comprising a filter provided in the discharge unit.   The kneaded material is an electrode mixture containing at least an active material, a binder, and a solvent, and the discharge portion includes opening / closing means disposed inside the container from the filter, and the opening / closing means is configured to close the raw material when closed. The kneading machine according to claim 1 which prevents penetration to said filter.   The kneading machine according to claim 1 or 2, wherein the container is provided with a supply port that enables introduction of gas into the container at an upper part of the container.   The kneading machine according to any one of claims 1 to 3, wherein the discharge portion is disposed at a bottom portion of the container.