Electricity storage device electrode slurry manufacturing apparatus and method of manufacturing electricity storage device electrode slurry

Abstract

To improve the quality of an electrode slurry.SOLUTION: An electrode slurry manufacturing apparatus 10 includes a material loading unit 30, a feeder unit 40, and a multi-screw kneader 50 .The material loading unit 30 puts a plurality of types of electrode materials A-C collectively into the feeder unit 40. The feeder unit 40 includes an inlet opening 41a, an agitation chamber 41, a discharge opening 41b1, feeding blades 43, 44 and a spiral shaped blade 45. Into the inlet opening 41a, the electrode materials A-C are loaded from the material loading unit 30. The electrode materials A-C are agitated in the agitation chamber 41. The discharge opening 41b1 is disposed in a bottom part 41b of the agitation chamber 41. The feeding blades 43, 44 are mounted to a shaft 46 disposed on the bottom part 41b of the agitation chamber 41. The feeding blades 43, 44 feed the electrode materials A-C to the discharge opening 41b1. The spiral shaped blade 45 is disposed above the feeding blades 43, 44 and is mounted to the shaft 46.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an apparatus for producing slurry for an electrode of an electric storage device and a method for producing slurry for an electrode of an electric storage device. Regarding. [Background technology]

[0002] Japanese Patent Application Laid-Open Publication No. 2011-233380 discloses a continuous manufacturing apparatus for secondary battery electrode slurry, which continuously produces electrode slurry. The continuous manufacturing apparatus includes a supply unit, a mechanochemical processing unit, a first kneading / dispersion processing unit, and a second dispersion processing unit. The supply unit supplies a powdered battery material containing at least a powdered electrode active material. The mechanochemical processing unit performs mechanochemical processing on the powdered battery material. The first kneading / dispersion processing unit performs kneading / dispersion processing on a liquid binder and the mechanochemically treated material. The second kneading / dispersion processing unit dilutes the kneaded material processed in the first kneading / dispersion processing unit with a diluent. This continuous manufacturing apparatus is said to be capable of continuously manufacturing electrode slurry with good reproducibility. [Prior art documents] [Patent documents]

[0003] [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-233380 Summary of the Invention [Problem to be solved by the invention]

[0004] The present inventors wish to improve the quality of electrode slurries produced using multiple electrode materials. [Means for solving the problem]

[0005] The electrode slurry manufacturing apparatus disclosed herein comprises a material input device, a feeder, and a multi-shaft kneader. The material feeder is configured to feed multiple types of electrode materials into the feeder all at once. The feeder is equipped with an inlet, a stirring chamber, a discharge outlet, a feed blade, and a spiral blade. The electrode material is fed from the material feeder into the inlet. The electrode material is stirred in the stirring chamber. The discharge outlet is provided at the bottom of the stirring chamber. The electrode material is delivered from the discharge outlet towards the multi-shaft kneader. The feed blade is attached to a shaft provided at the bottom of the stirring chamber. The feed blade delivers the electrode material to the discharge outlet. The spiral blade is positioned above the feed blade and attached to the shaft. Such an electrode slurry manufacturing apparatus improves the quality of electrode slurry manufactured using multiple types of electrode materials. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a flowchart of a method for producing an electrode slurry. [Figure 2] FIG. 2 is a schematic diagram of an electrode slurry production apparatus 10. As shown in FIG. [Figure 3] FIG. 3 is a schematic diagram of the feeder 40. [Figure 4] FIG. 4 is a schematic diagram of a feeder 40A according to another embodiment. [Figure 5] FIG. 5 is a schematic diagram of a feeder 40B according to another embodiment. [Figure 6] FIG. 6 is a schematic diagram of a feeder 40C according to another embodiment. [Figure 7] FIG. 7 is a schematic diagram of a feeder 40D according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] An embodiment of the technology disclosed herein will be described below with reference to the drawings. The embodiment described here is, of course, not intended to limit the present invention. The drawings are schematic and do not necessarily reflect the actual product. Furthermore, the same reference numerals are appropriately used for components and parts that perform the same function, and redundant explanations will be omitted where appropriate.

[0008] <Battery manufacturing method> Fig. 1 is a flowchart of a method for producing electrode slurry. As shown in Fig. 1, the method includes step S1 of measuring out a predetermined weight of each of a plurality of electrode materials and placing the materials in a feeder, step S3 of stirring the plurality of electrode materials in the feeder, step S5 of feeding the stirred plurality of electrode materials to a multi-screw kneader, and step S7 of kneading the plurality of electrode materials in the multi-screw kneader. The electrode slurry is produced using an electrode slurry production apparatus 10 (see Fig. 2).

[0009] The electrode slurry production apparatus and electrode slurry production method disclosed herein are applicable to production apparatuses and production methods for electrode slurries used in various power storage devices. Here, the term "power storage device" is a concept that encompasses devices in which charge carriers move between a pair of electrodes (positive and negative electrodes), causing charge-discharge reactions. Power storage devices in the technology disclosed herein include secondary batteries such as lithium-ion secondary batteries, nickel-metal hydride batteries, and nickel-cadmium batteries, as well as capacitors such as lithium-ion capacitors and electric double-layer capacitors. Below, the technology disclosed herein will be described using as an example a production apparatus and production method for producing electrode slurry for lithium-ion secondary batteries.

[0010] <Electrode slurry manufacturing device 10> FIG. 2 is a schematic diagram of an electrode slurry production apparatus 10. In FIG. 2, the direction in which materials are supplied or fed is indicated by an arrow. In the electrode slurry production apparatus 10, an electrode material and a solvent are mixed together to produce an electrode mixture slurry. In this embodiment, the electrode slurry production apparatus 10 produces a positive electrode mixture slurry containing a positive electrode mixture. As shown in FIG. 2, the electrode slurry production apparatus 10 includes a material supply machine 20, a material input machine 30, a supply machine 40, and a multi-shaft kneader 50.

[0011] First, a plurality of types of electrode materials A to C are each weighed out by a predetermined weight in the material supplying machine 20, and are then put into the supplying machine 40 by the material inputting machine 30 (S1).

[0012] <Material feeder 20> The material supply machine 20 includes supply machines 21 to 23 and weighing machines 27 to 29. The supply machines 21 to 23 supply powder electrode materials A to C, respectively. Known devices capable of supplying a fixed amount of powder material can be used as the supply machines 21 to 23. A circle feeder, a screw feeder, a rotary feeder, a belt feeder, etc. can be used as the supply machines 21 to 23.

[0013] The supplying machines 21 and 23 contain electrode materials A and C. In this embodiment, the electrode materials A and C are lithium nickel cobalt manganese composite oxides as positive electrode active materials. Here, the electrode material A has an average particle diameter of 4 μm and a tap density of 2.2 g / cm. 3 Electrode material C is a lithium nickel cobalt manganese composite oxide with an average particle size of 17 μm and a tap density of 2.4 g / cm 3 The electrode material B is a lithium nickel cobalt manganese composite oxide. The supply device 22 contains an electrode material B. In this embodiment, the electrode material B is polyvinylidene difluoride (PVDF) as a binder. Here, the electrode material B has a density of 1 g / cm 3 It is PVDF.

[0014] The positive electrode active material and binder are not particularly limited, and various materials conventionally used as positive electrode active materials and binders for lithium ion secondary batteries can be used without particular limitations. For example, the positive electrode active material may be lithium nickel oxide (e.g., LiNiO2), lithium cobalt oxide (e.g., LiCoO2), lithium manganese oxide (e.g., LiMn2O4), or a composite thereof (e.g., LiNi 0.5 Mn 1.5 O4, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3Particles of oxides (lithium transition metal oxides) containing lithium and transition metal elements as constituent metal elements, such as lithium manganese phosphate (LiMnPO4) and lithium iron phosphate (LiFePO4), and particles of phosphates containing lithium and transition metal elements as constituent metal elements, such as lithium manganese phosphate (LiMnPO4) and lithium iron phosphate (LiFePO4), can be used. Examples of binders that can be used include acrylic resins such as (meth)acrylic acid ester polymers, vinyl halide resins such as polyvinylidene fluoride (PVDF), and polyalkylene oxides such as polyethylene oxide (PEO). In addition, from the viewpoint of ease of stirring and kneading in subsequent processes, the density (or tap density) of the powder electrode material supplied from the supplying machine should be 0.5 to 3.0 g / cm. 3 It is preferable that:

[0015] The weighing machines 27 to 29 are devices for weighing the electrode materials A to C supplied from the supply machines 21 to 23. The weighing machines 27 to 29 each carry a container 31 into which the electrode materials A to C supplied from the supply machines 21 to 23 are placed. The containers 31 are arranged on an index table 25. A plurality of containers 31 (six in the embodiment shown in FIG. 2) can be arranged on the index table 25. The index table 25 is rotated in a predetermined direction at a predetermined timing by a drive unit 25b connected to an axis 25a. As the index table 25 rotates, the container 31 sequentially moves to positions where the electrode materials A to C are supplied from the supply machines 21 to 23. At this time, the weighing machines 27 to 29 respectively measure the weights of the electrode materials A to C supplied to the container 31. When the container 31 moves to the positions where the electrode materials A to C are supplied, the other containers 31 also move in the same direction and at the same timing. When the material is supplied to one container 31, the material is sequentially supplied to other containers 31 following that container 31.

[0016] The weighing machines 27 to 29 measure predetermined weights of the electrode materials A to C, respectively. Scales, load cells, etc., can be used as the weighing machines 27 to 29. First, the container 31 moves to a position where the electrode material A is supplied. The container 31 is set in the weighing machine 27. The weighing machine 27 measures the weight of the electrode material A supplied from the supply machine 21 to the container 31. Next, the container 31 moves to a position where the electrode material B is supplied. The container 31 is set in the weighing machine 28. The weighing machine 28 measures the weight of the electrode material B supplied from the supply machine 22 to the container 31. Next, the container 31 moves to a position where the electrode material C is supplied. The container 31 is set in the weighing machine 29. The weighing machine 29 measures the weight of the electrode material C supplied from the supply machine 23 to the container 31.

[0017] The weights of the electrode materials A to C measured by the weighing machines 27 to 29 are appropriately set depending on the composition of the target electrode mixture slurry. The weight ratio of the positive electrode active material, binder, and conductive material contained in the positive electrode mixture slurry can be set to, for example, approximately positive electrode active material:binder:conductive material = 96.0 to 99.0:0.5 to 2.0:0.5 to 2.0. In this embodiment, the weight ratio of the positive electrode active material, binder, and conductive material contained in the positive electrode mixture slurry is set to positive electrode active material:binder:conductive material = 97.5:1.0:1.5. The weighing machines 27 to 29 measure the electrode materials A to C in the container 31 so that the weight ratio of electrode material A (positive electrode active material):electrode material B (binder):electrode material C (positive electrode active material) = 48.75:1.0:48.75. In this embodiment, acetylene black (AB) is used as the conductive material. Acetylene black as a conductive material is placed in the form of a paste into a multi-screw kneader 50, which will be described later.

[0018] In this embodiment, electrode materials A to C are placed in container 31 in the order of electrode material A, electrode material B, and electrode material C. Electrode material A (positive electrode active material), electrode material B (binder), and electrode material C (positive electrode active material) are placed in container 31 in this order from the bottom of container 31 toward the opening. In step S1 of placing in container 31, a positive electrode active material with a relatively high density is placed in container 31, followed by a binder with a relatively low density in container 31, and then another positive electrode active material with a relatively high density is placed in container 31.

[0019] The method for putting the electrode materials A to C into the material feeder 30 is not particularly limited. For example, the electrode materials A to C may be weighed in different containers and then put into the container 31. The order in which the electrode materials A to C are put into the container 31 is not limited to the above-mentioned form. For example, the electrode materials A to C may be put into the container 31 in the order of electrode material C, electrode material B, and electrode material A. The order in which the materials are put into the container 31 may be set as appropriate depending on the physical properties, number, etc. of the materials.

[0020] <Material feeder 30> The material feeder 30 is configured to feed a plurality of types of electrode materials A to C collectively into the supply device 40. In this embodiment, a reversing feeder that reversing a container 31 to feed the electrode materials A to C into the supply device 40 is used as the material feeder 30. Hereinafter, the material feeder 30 will also be referred to as a reversing feeder 30. Note that the material feeder 30 is not limited to the reversing feeder 30, and any conventionally known material feeder can be used. The material feeder 30 may be a circle feeder, a screw feeder, a rotary feeder, a belt feeder, or the like.

[0021] The reversing inserter 30 includes an arm 32 and a drive unit 33. The arm 32 is configured to be able to grip the container 31. The drive unit 33 is a device that drives the arm 32 around a fulcrum 32a set on the arm 32 as an axis. The drive unit 33 can be realized by, for example, a motor, a sprocket, etc.

[0022] In this embodiment, the driving device 33 rotates the arm 32 toward the supply device 40 around the fulcrum 32a. The driving device 33 stops the arm 32 after rotating it approximately 180 degrees. As a result, the opening of the container 31 is inverted from an upward-facing state (shown by the dashed line in FIG. 2) to a downward-facing state. The positions of the inverting feeder 30 and the supply device 40 are set so that the container 31 is inverted above the stirring chamber 41 (see FIG. 3) of the supply device 40. An inlet 41a (see FIG. 3) through which the materials are introduced is provided at the top of the stirring chamber 41. The electrode materials A to C fall from the inverted container 31 and are introduced into the stirring chamber 41 through the inlet 41a. The electrode materials A to C are introduced from the container 31 into the stirring chamber 41 in the following order: electrode material C, electrode material B, and electrode material A. Note that a device other than the inverting feeder 30 may be used to introduce the electrode materials A to C into the supply device 40. For example, a lifting type inverting machine may be used in which the container is lifted and inverted along a lifting axis.

[0023] After the electrode materials A to C have been placed in the supply machine 40, the arm 32 is driven in the reverse direction by the drive device 33. The container 31 is returned to the index table 25. Thereafter, the container 31 moves as the index table 25 rotates. At this time, a new container 31 containing the weighed electrode materials A to C is sent to the reversing feeder 30. By repeating this process, the containers 31 containing the electrode materials A to C are sent to the reversing feeder 30 at regular intervals.

[0024] The electrode materials A to C are intermittently charged into the supply device 40 by the reversing charger 30. The weighing of the electrode materials A to C by the material supply device 20 and the reversing charge of the electrode materials A to C by the reversing charger 30 can be performed in conjunction with each other. In this embodiment, the charging of the electrode materials A to C into the container 31 of the reversing charger 30 and the reversing charge from the reversing charger 30 to the supply device 40 are repeated in a cycle of approximately 30 seconds. Therefore, a substantially constant amount of the electrode materials A to C is charged into the supply device 40 at substantially constant intervals. In other words, step S1 of weighing the electrode materials A to C and charging them into the supply device 40 is repeatedly performed at constant intervals. The electrode materials A to C, the weight ratio of which has been adjusted, can be supplied into the supply device 40 at predetermined intervals. Because the electrode materials A to C are weighed each time they are charged into the supply device 40, the weight ratio of the electrode materials A to C in the supply device 40 is likely to be stable. Even when a plurality of electrode materials A to C are used, the compounding ratio of the mixed powder material fed into the feeder 40 is easily guaranteed.

[0025] The electrode materials A to C placed in the supplying machine 40 are stirred inside the supplying machine 40 (S3).

[0026] <Feeder 40> FIG. 3 is a schematic diagram of the feeder 40. In FIG. 3, the direction in which the electrode materials A to C are fed and the direction in which the spiral blade 45 rotates are indicated by arrows. FIG. 3 also shows a schematic cross section of the feeder 40 along its height direction. In this embodiment, a constant volume feeder (hereinafter referred to as feeder 40) that continuously supplies a predetermined amount of material is used as the feeder 40. In this embodiment, the feeder 40 is a so-called circle feeder. By using a circle feeder as the feeder 40, the supply amounts of the electrode materials A to C are stabilized and the equipment can be made more compact.

[0027] 3, the feeder 40 includes an inlet 41a, a stirring chamber 41, a discharge outlet 41b1, feed blades 43 and 44, and a spiral blade 45. The inlet 41a and the discharge outlet 41b1 are provided in the stirring chamber 41. Electrode materials A to C are fed into the inlet 41a from the material feeder 30. The electrode materials A to C are stirred in the stirring chamber 41. The electrode materials A to C stirred in the stirring chamber 41 are sent out from the discharge outlet 41b1 toward the multi-shaft kneader 50.

[0028] <Stirring chamber 41> The stirring chamber 41 is formed in a substantially cylindrical shape. The top of the stirring chamber 41 is open, and an inlet 41a is formed therein through which the electrode materials A to C are introduced. The stirring chamber 41 has a substantially disc-shaped bottom 41b. An outlet 41b1 is formed in a portion of the bottom 41b. The stirring chamber 41 is connected to the constant-quantity feed chamber 42 via the outlet 41b1. An intermediate plate 41c is provided above the outlet 41b1. The intermediate plate 41c is substantially disc-shaped except for an opening 41c1 formed in a portion of the bottom 41b. The intermediate plate 41c is sized to cover at least the upper portion of the outlet 41b1. The opening 41c1 of the intermediate plate 41c and the outlet 41b1 of the bottom 41b are formed at different positions in a plan view. The opening 41c1 of the intermediate plate 41c and the outlet 41b1 of the bottom 41b are provided on opposite sides of a shaft 46 provided in the approximately center of the bottom 41b.

[0029] <Feathers 43, 44> The feed blades 43, 44 feed the electrode materials A to C toward the discharge port 41b1. The feed blades 43, 44 are attached to a shaft 46. The feed blades 43, 44 rotate in accordance with the rotation of the shaft 46. The shaft 46 is composed of a lower portion 46a and an upper portion 46b. The lower portion 46a and the upper portion 46b of the shaft 46 are each approximately cylindrical. The lower portion 46a has a larger diameter and is shorter than the upper portion 46b. The shaft 46 is provided on the bottom portion 41b and extends upward from approximately the center of the bottom portion 41b.

[0030] The feed blades 43, 44 are generally rod-shaped members. The feed blades 43, 44 extend radially outward from the shaft 46. The feed blade 43 is provided below the intermediate plate 41c. The feed blade 44 is provided above the intermediate plate 41c. In other words, the feed blades 43 and 44 are provided at positions sandwiching the intermediate plate 41c. The feed blade 43 extends along the upper surface of the bottom 41b. Four feed blades 43 extend from a portion of the lower part 46a of the shaft 46 below the intermediate plate 41c. The four feed blades 43 are provided at approximately equal intervals in the circumferential direction of the shaft 46. The feed blade 44 extends along the upper surface of the intermediate plate 41c. Two feed blades 44 extend in opposite directions from a portion of the lower part 46a of the shaft 46 below the intermediate plate 41c. A drive unit 47 is connected to the shaft 46. The drive unit 47 is, for example, a motor. The drive unit 47 may be connected to the shaft 46 via a reducer, a transmission, or the like. The drive unit 47 drives the shaft 46 to rotate, thereby rotating the feed blades 43 and 44.

[0031] <Spiral Wing 45> The spiral blade 45 stirs the electrode materials A to C in the stirring chamber 41. The spiral blade 45 is attached to an upper part 46b of the shaft 46. The spiral blade 45 rotates in accordance with the rotation of the shaft 46. The spiral blade 45 is disposed on a feed blade 43 attached to a lower part 46a of the shaft 46. When the drive unit 47 rotates the shaft 46, the feed blades 43 and 44 and the spiral blade 45 rotate in the same direction and at the same rotation speed along the circumferential direction of the shaft 46. The "spiral blade 45" is a member wound in a predetermined direction in the circumferential and height directions of the shaft 46.

[0032] In this embodiment, the spiral blade 45 is plate-shaped and wound around the shaft 46. In other words, the spiral blade 45 is connected to the outer circumferential surface of the shaft 46 in the radial direction of the shaft 46. The spiral blade 45 is a so-called screw blade. The spiral blade 45 is wound two times clockwise from the base end to the tip. A substantially constant gap is left between the outer edge of the spiral blade 45 and the inner circumferential surface of the stirring chamber 41 in the radial direction. The gap is set to a dimension that allows the electrode materials A to C to pass through.

[0033] A plurality of holes 45a are formed in the spiral blade 45. The dimensions of the plurality of holes 45a are set to allow the electrode materials A to C to pass through. The dimensions of the holes 45a are not particularly limited, but the inner diameter or the interval between the narrowest parts may be set to 1 mm or more, and preferably set to, for example, 3 mm or more. The dimensions of the holes 45a are not particularly limited, but the inner diameter or the interval between the narrowest parts may be set to 20 mm or less, and preferably set to, for example, 10 mm or less.

[0034] Hole 45a is an elongated hole extending in the radial direction of shaft 46. The shape of hole 45a is not particularly limited. In this embodiment, the outer shape of hole 45a is a substantially oval shape formed by a pair of parallel straight lines and an arc-shaped line connecting the pair of parallel straight lines. The shape of hole 45a is not limited to this oval shape, and may be a polygonal shape such as a rectangle, or an elliptical shape. Although not particularly limited, the ratio of the major axis to the minor axis of hole 45a (aspect ratio) is preferably greater than 1 and equal to or greater than 2. The ratio of the major axis to the minor axis of hole 45a may be 10 or less, and preferably equal to or less than 7. Hole 45a does not necessarily have to be an elongated hole, and may be a circular shape or a regular polygon such as a square.

[0035] The plurality of holes 45a are formed intermittently along the winding direction of the spiral blade 45. The plurality of holes 45a have approximately the same size and shape and are formed at approximately regular intervals. The plurality of holes 45a are formed radially toward the outer edge of the spiral blade 45. The holes 45a are provided outside the middle portion in the width direction of the spiral blade 45 (radial direction of the shaft 46). The centers of the holes 45a are located outside the middle portion in the width direction of the spiral blade 45.

[0036] The electrode materials A to C are stirred in the above-mentioned feeder 40. Hereinafter, the feeding of the electrode materials A to C to the feeder 40 and the stirring in the feeder 40 will be described.

[0037] By inverting the container 31 above the stirring chamber 41, the electrode materials A to C introduced through the inlet 41a are introduced into the supply machine 40 in the reverse order to the order in which they were introduced into the container 31 (in this embodiment, the order of electrode materials C, B, A).

[0038] Within the stirring chamber 41 of the feeder 40, the feed blades 43, 44 and the spiral blade 45 rotate in response to the rotation of the shaft 46 by the drive device 47. Here, the feed blades 43, 44 and the spiral blade 45 rotate counterclockwise (the opposite direction to the direction in which the spiral blade 45 winds from the bottom end to the top end). When the electrode materials A to C are introduced into the stirring chamber 41, the introduced electrode materials A to C collide with the rotating spiral blade 45 and accumulate within the stirring chamber 41.

[0039] Some of the electrode materials A to C accumulate at a position below the upper end of the feed blade 44. The electrode materials A to C that have accumulated at a position below the upper end of the feed blade 44 are sent by the feed blade 44 toward the opening 41c1. The sent electrode materials A to C fall downward from the opening 41c1 and accumulate at the bottom 41b. The electrode materials A to C that have accumulated at the bottom 41b are sent by the feed blade 43 toward the discharge opening 41b1. The sent electrode materials A to C are discharged from the discharge opening 41b1.

[0040] Some of the electrode materials A to C accumulate at a position higher than the feed blade 44. The electrode materials A to C that have accumulated at a position higher than the feed blade 44 are agitated in the direction of rotation of the rotating spiral blade 45. In addition, some of the electrode materials A to C can be lifted upward by the rotating spiral blade 45. The lifted electrode materials A to C fall downward from holes 45a formed in the spiral blade 45 or fall from the outer edge of the spiral blade 45. This allows the electrode materials A to C to be agitated in the vertical direction as well.

[0041] If the electrode materials A to C that have fallen downward accumulate at a position higher than the feed blade 44, they can be lifted up again and stirred by the spiral blade 45. If the electrode materials A to C that have fallen downward accumulate at a position below the upper end of the feed blade 44, they are sent by the feed blade 44 toward the opening 41c1. Next, the electrode materials A to C are sent by the feed blade 43 toward the discharge opening 41b1. In this way, the electrode materials A to C are discharged from the discharge opening 41b1 at approximately constant amounts by the feed blades 43, 44 while being stirred by the spiral blade 45.

[0042] The electrode materials A to C are intermittently charged by the material charger 30. The electrode materials A to C charged by the material charger 30 may accumulate on top of the electrode materials A to C already accumulated in the stirring chamber 41. For this reason, the newly charged electrode materials A to C are agitated by the spiral blade 45 and sequentially discharged from the discharge port 41b1. In this embodiment, the height of the spiral blade 45 reaches a position higher than the height of the electrode materials A to C that may accumulate in the stirring chamber 41. This can improve the agitation efficiency of the electrode materials A to C. As described above, in the stirring chamber 41, the electrode materials A to C are sequentially charged by the material charger 30, agitated by the spiral blade 45, and discharged from the discharge port 41b1.

[0043] In this embodiment, the constant-volume feed chamber 42 is connected to the discharge port 41b1 of the stirring chamber 41. The constant-volume feed chamber 42 is generally cylindrical and shorter than the stirring chamber 41. A feed blade 42a is provided in the constant-volume feed chamber 42. The feed blade 42a is attached to a shaft 42b. The shaft 42b extends upward from approximately the center of the bottom 42c. The feed blade 42a extends in a curved manner radially outward from the shaft 42b along the bottom 42c. The feed blade 42a having such a shape facilitates stabilizing the amount of electrode materials A to C fed. The height of the feed blade 42a decreases radially outward. In this embodiment, four feed blades 42a extend from the shaft 42b. The shape, number, etc. of the feed blades 42a are not particularly limited and can be appropriately determined depending on the type of material, etc. A drive unit 47 is connected to the shaft 42b. Therefore, feed blade 42a rotates at the same timing as feed blades 43, 44 and spiral blade 45. A discharge port 42c1 is formed in bottom portion 42c of constant quantity supply chamber 42. Note that constant quantity supply chamber 42 does not necessarily have to be provided.

[0044] The amounts of electrode materials A to C discharged from discharge opening 42c1 are set according to the rotation speed of feed blades 42a, 43, and 44. By driving drive device 47 to rotate feed blades 42a, 43, and 44 at a constant speed, approximately constant amounts of electrode materials A to C can be continuously discharged from discharge opening 42c1. The rotation speed of feed blades 42a, 43, and 44 is not particularly limited, but can be set appropriately according to the intervals at which electrode materials A to C are reversed and charged, the amounts, and the like.

[0045] The stirred electrode materials A to C are discharged from the discharge port 41b1 of the feeder 40 and supplied to the multi-screw kneader 50 (S5).

[0046] <Multi-screw kneader 50> The multi-screw kneader 50 (see FIG. 2) is an apparatus for kneading electrode materials A to C while applying shear force to them. The electrode materials A to C are kneaded while being transported in the transport direction inside the multi-screw kneader 50. As shown in FIG. 2, the multi-screw kneader 50 includes a barrel 51, a shaft 52 provided inside the barrel 51, and a drive device 53 for driving the shaft 52. In this embodiment, a twin-screw kneader 50 having two shafts 52 extending approximately parallel inside the barrel 51 is used as the multi-screw kneader 50. The twin-screw kneader 50 may be provided with a thermometer for measuring the temperature of the material inside the barrel 51, a chiller for adjusting the temperature of the material inside the barrel 51, and the like. Note that the apparatus for kneading the electrode material is not limited to a twin-screw kneader and may be, for example, a multi-screw kneader such as a four-screw kneader.

[0047] The barrel 51 is cylindrical and has a space therein for containing electrode materials, a solvent, and the like. One end of the barrel 51 is provided with a powder supply port 51a through which electrode materials A to C are supplied. The powder supply port 51a is connected to an outlet 41b1 of the supply device 40. In this embodiment, the powder supply port 51a is connected to the outlet 41b1 via an outlet 42c1 of the constant-quantity supply chamber 42. A plurality of solvent supply ports 51b are provided downstream of the powder supply port 51a. A solvent supply device 55 is connected to the solvent supply port 51b. A monopump may be connected to the solvent supply device 55 to maintain a constant discharge rate. A constant discharge rate of the solvent is continuously supplied from the solvent supply port 51b. Examples of the solvent that can be used include water and N-methyl-2-pyrrolidone (NMP). A paste inlet 51c is provided downstream of the plurality of solvent supply ports 51b. A paste supply device 56 is connected to the paste inlet 51c. Similar to the solvent supply device 55, a mohno pump may be connected to the paste supply device 56 to maintain a constant discharge rate. The mohno pump may be provided with a flow meter that measures the flow rates of the supplied solvent and paste. To stabilize the discharge rate, the rotation of the rotor of the mohno pump may be controlled according to the flow rate measured by the flow meter. A constant discharge rate of paste is continuously supplied from the paste inlet 51c. In this embodiment, a paste-like conductive material (acetylene black in this embodiment) is introduced from the paste inlet 51c. Thus, the materials for the positive electrode composite slurry are supplied into the barrel 51 in the order of electrode materials A to C, the solvent, and the conductive material. An outlet 51d is provided downstream of the paste inlet 51c. The outlet 51d is provided at the end of the barrel 51 opposite the powder supply port 51a. The completed positive electrode composite slurry is discharged from the outlet 51d.

[0048] A shaft 52 extending in the conveying direction is provided within the barrel 51. A screw 52a and a paddle 52b are provided on the shaft 52. A plurality of screws 52a and paddles 52b are provided along the conveying direction. The screws 52a and paddles 52b are provided on the outer circumferential surface of the shaft 52. The screw 52a has spirally wound blades. The paddle 52b is a plate-like member with its wide surface facing the conveying direction. Although not particularly limited, the paddle 52b has a polygonal shape (e.g., a triangle, a square, a hexagon, etc.) with curved corners. The side circumferential surface of the paddle 52b may also be curved. A predetermined gap is formed between the side circumferential surface of the paddle 52b and the inner circumferential surface of the barrel 51.

[0049] The driving device 53 may be a motor or the like that drives the shaft 52 to rotate. As the shaft 52 rotates, the screw 52a and the paddle 52b rotate in the circumferential direction of the shaft 52. The material in the barrel 51 is pushed by the blades of the screw 52a and transported in the transport direction. A shear force is applied to the material in the barrel 51 between the side circumferential surface of the paddle 52b and the inner circumferential surface of the barrel 51. The twin-screw kneader 50 may be provided with a pressure gauge that measures the pressure in the barrel 51. The driving of the driving device 53 may be controlled so that the pressure in the barrel 51 measured by the pressure gauge falls within a required pressure range.

[0050] The electrode materials A to C are kneaded using the above-mentioned twin-screw kneader 50 (S7).

[0051] The electrode materials A to C stirred in the feeder 40 are supplied from the powder supply port 51a into the barrel 51 of the twin-screw kneader 50. The electrode materials A to C are continuously supplied into the barrel 51 by the feeder 40 at approximately constant amounts per unit time.

[0052] The electrode materials A to C are conveyed in the conveying direction by the screw 52a. The electrode materials A to C are conveyed while being subjected to shear force as they pass between the side circumferential surface of the paddle 52b and the inner circumferential surface of the barrel 51. The electrode materials A to C conveyed inside the barrel 51 are mixed with a solvent supplied from a solvent supply port 51b. The solvent is introduced into the barrel 51 separately from multiple solvent supply ports 51b provided along the conveying direction. Therefore, the electrode materials A to C and the solvent are mixed in stages. This makes it less likely that unevenness will occur in the mixed materials. The materials conveyed inside the barrel 51 (here, the electrode materials A to C and the solvent) are mixed with a paste-like conductive material. The paste-like conductive material is introduced into the barrel 51 through a paste inlet 51c. The electrode materials A to C, the solvent, and the conductive material are conveyed while being mixed, and a positive electrode composite slurry is completed. The produced positive electrode composite slurry is discharged from a discharge port 51d.

[0053] A battery can be manufactured using the produced positive electrode mixture slurry by a known method. For example, the positive electrode mixture slurry is applied to both sides of a positive electrode current collector and dried. This is cut to a predetermined size and rolled using a roll press to prepare a positive electrode sheet with a positive electrode active material layer on both sides of the positive electrode current collector. A negative electrode mixture slurry is produced, and a negative electrode sheet with a negative electrode active material is prepared using a procedure similar to that used to prepare the positive electrode sheet. The positive electrode sheet and the negative electrode sheet are laminated with a separator sheet interposed between them to produce an electrode body. The electrode body is then housed in a battery case to produce a battery assembly. An electrolyte is poured into the battery assembly, and initial charging and aging are performed to produce a battery.

[0054] Incidentally, electrode slurry (electrode mixture slurry) used for electrodes contains multiple electrode materials. The multiple electrode materials are kneaded in a multi-screw kneader while applying high shear force. The kneaded electrode materials are then diluted and dispersed in a solvent or the like. However, the multiple electrode materials may have different physical properties, such as specific gravity, particle size, and viscosity. Furthermore, the electrode materials may contain materials that are difficult to uniformly disperse in a solvent or the like. Examples of materials that are difficult to uniformly disperse include binders and thickeners. When electrode materials with different physical properties are contained, or when an electrode material with poor dispersibility is contained, the materials may become non-uniform in the multi-screw kneader, and there is a concern that the materials may also become non-uniform in the finished electrode slurry. In this case, the electrode slurry may also become non-uniform when applied as an electrode mixture, which may result in unstable electrode quality.

[0055] In the embodiment described above, the electrode slurry manufacturing apparatus 10 includes a material input device 30, a supply device 40, and a multi-shaft kneader 50. The material input device 30 is configured to input multiple types of electrode materials A to C collectively into the supply device 40. The supply device 40 includes an input port 41a, a stirring chamber 41, a discharge port 41b1, feed blades 43 and 44, and a spiral blade 45. The electrode materials A to C are input from the material input device 30 into the input port 41a. The electrode materials A to C are stirred in the stirring chamber 41. The discharge port 41b1 is provided in the bottom 41b of the stirring chamber 41. The electrode materials A to C are sent out from the discharge port 41b1 toward the multi-shaft kneader 50. The feed blades 43 and 44 are attached to a shaft 46 provided in the bottom 41b of the stirring chamber 41. The feed blades 43 and 44 feed the electrode materials A to C to the discharge port 41b1. A spiral blade 45 is disposed above the feed blades 43 and 44 and is attached to a shaft .

[0056] In the electrode slurry production apparatus 10, the electrode materials A to C introduced into the stirring chamber 41 are stirred by the spiral blade 45, discharged from the discharge port 41b1 by the feed blades 43 and 44, and sent to the multi-shaft kneader 50. During stirring, the electrode materials A to C are stirred in the rotation direction of the rotating spiral blade 45. The electrode materials A to C can also be lifted by the spiral blade 45 or dropped from the spiral blade 45. This allows the electrode materials A to C to be stirred in both the rotation direction of the spiral blade 45 and the vertical direction within the stirring chamber 41. This improves the uniformity of the electrode materials A to C within the stirring chamber 41. By supplying the electrode materials A to C with good material uniformity to the multi-shaft kneader 50, it becomes easier to apply a uniform shear force to the electrode materials A to C within the multi-shaft kneader 50. The dispersibility of the electrode materials A to C can be improved within the multi-shaft kneader 50. As a result, the dispersibility of the electrode materials A to C in the electrode slurry is improved, and the quality of the electrode can be stabilized.

[0057] In the above-described embodiment, the spiral blade 45 is connected to the shaft 46 in the radial direction of the shaft 46. The lifted electrode materials A to C tend to fall from the outer edge of the spiral blade 45. This makes it easier for the electrode materials A to C to circulate along a path that lifts them and drops them outward from the outer edge of the spiral blade 45. As a result, the electrode materials A to C are more easily agitated in the vertical direction.

[0058] In the above-described embodiment, a plurality of holes 45a through which the electrode materials A to C pass is formed in the spiral blade 45. The lifted electrode materials A to C fall not only from around the spiral blade 45 but also from the holes 45a. By providing additional positions where the lifted electrode materials A to C fall, the electrode materials A to C are more easily agitated.

[0059] In the above-described embodiment, the plurality of holes 45a are formed intermittently along the winding direction of the spiral blade 45. The plurality of holes 45a are provided intermittently at different heights. This allows the electrode materials A to C to fall through the holes 45a at various heights. As a result, the electrode materials A to C are more easily agitated.

[0060] In the above-described embodiment, the holes 45a are elongated holes extending in the radial direction of the shaft 46. Since the holes 45a are aligned in the radial direction of the shaft 46, the electrode materials A to C lifted by the spiral blade 45 can more easily fall through the holes 45a. This makes it easier to agitate the electrode materials A to C.

[0061] In the above-described embodiment, the plurality of electrode materials A to C include a first electrode material (in this embodiment, PVDF as electrode material B) and a second electrode material (in this embodiment, positive electrode active materials as electrode materials A and C) having a density higher than that of the first electrode material. In the step of placing the materials in the container 31, a portion of the second electrode material (electrode material A) is placed in the container 31, followed by the first electrode material (electrode material B), and then the remainder of the second electrode material (electrode material C) is placed in the container 31. In the container 31, the electrode material B, which has a relatively low density, is sandwiched between the electrode materials A and C, which have a relatively high density. This can reduce the flying up of the electrode material B when the electrode materials A to C are placed in the container 31 and when the electrode materials A to C are placed from the container 31 to the feeder 40. As a result, the weight ratio of the electrode materials A to C supplied to the twin-screw kneader 50 is likely to be stable.

[0062] Although the method for producing a positive electrode composite slurry has been described as an example here, the present invention is not limited to this. The electrode slurry production apparatus 10 may also produce a negative electrode composite slurry.

[0063] The negative electrode mixture slurry may contain, for example, a negative electrode active material, a thickener, and a binder. The materials contained in the negative electrode mixture slurry are not particularly limited, and various materials conventionally used as materials for lithium-ion secondary batteries can be used without particular limitation. Examples of the negative electrode active material include carbon materials such as artificial graphite, natural graphite, amorphous carbon, and composites thereof (e.g., amorphous carbon-coated graphite), as well as materials that form alloys with lithium, such as silicon (Si), and lithium-storing compounds such as silicon compounds (e.g., SiO). Examples of the thickener include carboxymethyl cellulose (CMC). Examples of the binder include styrene butadiene rubber (SBR). The weight ratio of the negative electrode active material, thickener, and binder contained in the negative electrode mixture slurry may be set to, for example, approximately 96.0 to 99.0:0.5 to 2.0:0.5 to 2.0 (negative electrode active material:thickener:binder).

[0064] When producing a negative electrode composite slurry, a negative electrode active material and CMC as a thickener can be placed in container 31. SBR as a binder can be added through paste inlet 51c, similar to the paste-like acetylene black used when producing a positive electrode composite slurry. The process for producing a negative electrode composite slurry is similar to the process for producing a positive electrode composite slurry, and therefore a detailed description thereof will be omitted.

[0065] The configuration of the feeder 40 is not limited to the embodiment described above. Figures 4 to 7 are schematic diagrams of feeders 40A to 40D according to other embodiments. Holes 45a (see Figure 3) may be formed in the spiral blades 45A to 45D of the feeders 40A to 40D shown in Figures 4 to 7.

[0066] In the feeder 40A shown in FIG. 4, two spiral blades 45A are wound around the shaft 46. The two spiral blades 45A are symmetrical with respect to the shaft 46. Each of the two spiral blades 45A is wound about 1.5 times around the shaft 46. In the feeder 40B shown in FIG. 5, each of the two spiral blades 45B is wound about 1 time around the shaft 46. The feeder 40B has the same configuration as the feeder 40A, except that the number of turns of the two spiral blades 45B is about 1 time around the shaft 46. As such, the number of turns and the number of blades per unit length of the spiral blades wound around the shaft 46 are not particularly limited and can be set appropriately depending on the configuration of the electrode materials A to C, etc.

[0067] In the feeder 40C shown in FIG. 6, two spiral blades 45C are wound around a shaft 46. The spiral blades 45C are strip-shaped and wound around the shaft 46 at a substantially constant interval, except for the base and top ends. The spiral blades 45C have an upper surface on which the electrode materials A to C are placed. The spiral blades 45C are connected to rod-shaped members extending from the shaft 46 at the base and top ends of the shaft 46. This supports the shaft 46 and the spiral blades 45C with a gap between them. The two spiral blades 45C are symmetrical with respect to the shaft 46. Each of the two spiral blades 45C is wound around the shaft 46 approximately 1.5 times. The electrode materials A to C can fall not only from the outer edge of the spiral blade 45C but also from the gap (the inner edge of the spiral blade 45C). 7, two spiral blades 45D are each wound approximately one turn around shaft 46. Supply device 40D has the same configuration as supply device 40C, except that two spiral blades 45D are wound approximately one turn around shaft 46. In this manner, a gap may be formed around shaft 46 and the spiral blades.

[0068] According to the inventor's experiments, it was found that the fewer the number of spiral blades, the easier it is to stir an electrode material with a small particle size, and the more the number of spiral blades, the easier it is to stir an electrode material with a large particle size. It was also found that the fewer the number of turns of the spiral blade, the easier it is to stir an electrode material with a small particle size, and the more the number of turns of the spiral blade, the easier it is to stir an electrode material with a large particle size. It was also found that when the particle size of the electrode material is small, forming a gap between the shaft and the spiral blade makes it easier to stir the electrode material. When producing the positive electrode composite slurry of the above-described embodiment, it was found that, among the supplying devices 40A to 40D, using the supplying device 40A makes it easier to diffuse the electrode materials A to C.

[0069] The technology disclosed herein has been described in various ways. Unless otherwise specified, the embodiments and the like described herein do not limit the present invention. Furthermore, the technology disclosed herein can be modified in various ways, and as long as no particular problems arise, each component and each process described herein can be omitted or combined as appropriate. Furthermore, this specification includes the disclosures described in the following sections.

[0070] Section 1: A material feeder, A feeder; Multi-shaft mixer and Equipped with the material input device is configured to input a plurality of types of electrode materials into the supply device at once, The feeder is an inlet through which the electrode material is introduced from the material introduction device; a stirring chamber in which the electrode material is stirred; a discharge port provided at the bottom of the stirring chamber, through which the electrode material is fed toward the multi-shaft kneader; a feed blade attached to a shaft provided at the bottom of the stirring chamber and feeding the electrode material to the discharge port; a spiral blade disposed on the feed blade and attached to the shaft; Equipped with Electrode slurry manufacturing equipment.

[0071] Section 2: Item 2. The electrode slurry manufacturing apparatus according to item 1, wherein the spiral blade is connected to the shaft in the radial direction of the shaft.

[0072] Section 3: Item 3. The electrode slurry producing apparatus according to item 1 or 2, wherein the spiral blade has a plurality of holes formed therein through which the electrode material passes.

[0073] Section 4: Item 4. The electrode slurry manufacturing apparatus according to item 3, wherein the plurality of holes are formed intermittently along the winding direction of the spiral blade.

[0074] Section 5: Item 5. The electrode slurry producing apparatus according to item 3 or 4, wherein the hole is a long hole extending in a radial direction of the shaft.

[0075] Item 6: a step of measuring a plurality of types of electrode materials by a predetermined weight and placing the materials in a supplying machine; agitating the plurality of electrode materials in the feeder; supplying the stirred electrode materials to a multi-screw kneader; kneading the plurality of electrode materials in the multi-screw kneader; Including, The feeder is an inlet into which the electrode material is input from a material input device; a stirring chamber in which the electrode material is stirred; a discharge port provided at the bottom of the stirring chamber, through which the electrode material is fed toward the multi-shaft kneader; a feed blade attached to a shaft provided at the bottom of the stirring chamber and feeding the electrode material to the discharge port; a spiral blade disposed on the feed blade and attached to the shaft; Equipped with A method for producing electrode slurry. [Explanation of symbols]

[0076] A~C Electrode material 10. Electrode slurry manufacturing equipment 20 Material feeding machine 21~23 Feeding machine 25 Index Table 25a axis 25b Drive unit 27~29 Weighing machine 30 Material input machine (reversing input machine) 31 Container 32 Arm 32a Fulcrum 33 Drive unit 40,40A~40D feeding machine 41 Stirring chamber 41a Inlet 41b bottom 41b1,42c1 Outlet 41c intermediate plate 41c1 opening 42 Quantitative supply room 42a, 43, 44 Feed blade 42b axis 42c bottom 43,44 Feed blade 45, 45A~45D Spiral blade 45a hole 46 axes 46a lower part 46b upper part 47 Drive Unit 50 Multi-screw mixer (twin-screw mixer) 51 barrels 51a Powder supply port 51b Solvent supply port 51c Paste inlet 51d outlet 52 Shaft 52a screw 52b Paddle 53 Drive unit 55 Solvent supply device 56 Paste supply device

Claims

1. A material feeder, A feeder; Multi-shaft mixer and Equipped with the material input device is configured to input a plurality of types of electrode materials into the supply device at once, The feeder is an inlet through which the electrode material is introduced from the material introduction device; a stirring chamber in which the electrode material is stirred; a discharge port provided at the bottom of the stirring chamber, through which the electrode material is fed toward the multi-shaft kneader; a feed blade attached to a shaft provided at the bottom of the stirring chamber and feeding the electrode material to the discharge port; a spiral blade disposed on the feed blade and attached to the shaft; Equipped with Electrode slurry manufacturing equipment.

2. 2. The electrode slurry producing apparatus according to claim 1, wherein the spiral blade is connected to the shaft in a radial direction of the shaft.

3. 3. The electrode slurry producing apparatus according to claim 1, wherein the spiral blade has a plurality of holes formed therein through which the electrode material passes.

4. 4. The electrode slurry producing apparatus according to claim 3, wherein the plurality of holes are formed intermittently along the winding direction of the spiral blade.

5. 4. The electrode slurry producing apparatus according to claim 3, wherein the hole is an elongated hole extending in a radial direction of the shaft.

6. a step of measuring a plurality of types of electrode materials by a predetermined weight and placing the materials in a supplying machine; agitating the plurality of electrode materials in the feeder; supplying the stirred electrode materials to a multi-screw kneader; kneading the plurality of electrode materials in the multi-screw kneader; Including, The feeder is an inlet into which the electrode material is input from a material input device; a stirring chamber in which the electrode material is stirred; a discharge port provided at the bottom of the stirring chamber, through which the electrode material is fed toward the multi-shaft kneader; a feed blade attached to a shaft provided at the bottom of the stirring chamber and feeding the electrode material to the discharge port; a spiral blade disposed on the feed blade and attached to the shaft; Equipped with A method for producing electrode slurry.

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