Apparatus for producing slurry for electricity storage device electrode and method for producing slurry for electricity storage device electrode

Abstract

The invention provides an apparatus for producing a slurry for an electricity storage device electrode and a method for producing a slurry for an electricity storage device electrode. This electrode slurry manufacturing device is provided with a material input machine, a supply machine, and a multi-shaft kneading machine. The material feeding machine feeds a plurality of electrode materials into the supply machine in a centralized manner. The feeder is provided with an input port, a stirring chamber, a discharge port, a conveying blade, and a spiral blade. An electrode material is fed from a material feeding machine to a feeding port. In the stirring chamber, the electrode material is stirred. The discharge port is formed in the bottom of the stirring chamber. The conveying blade is installed on a shaft arranged at the bottom of the stirring chamber. The conveying blade conveys the electrode material to the discharge port. The spiral blade is disposed on the conveying blade and is attached to the shaft.

Description

Technical Field

[0001] The present invention relates to an apparatus for producing slurry for electrical storage device electrodes and a method for producing slurry for electrical storage device electrodes. Background Art

[0002] Japanese Patent Application Publication No. 2011-233380 discloses a continuous manufacturing apparatus for electrode slurry for secondary batteries that continuously manufactures electrode slurry. The continuous manufacturing apparatus includes a supply unit, a mechanochemical treatment unit, a first kneading and dispersing unit, and a second dispersing unit. The supply unit supplies a powdered battery material containing at least a powdered electrode active material. The mechanochemical treatment unit performs a mechanochemical treatment on the powdered battery material. The first kneading and dispersing unit kneads and disperses the liquid binder and the mechanochemically treated product. The second kneading and dispersing unit dilutes the kneaded product treated in the first kneading and dispersing unit with a diluent. This continuous manufacturing apparatus enables the continuous and reproducible manufacture of electrode slurry.

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2011-233380 Summary of the Invention

[0004] The present inventors have studied to improve the quality of electrode slurries produced using various electrode materials.

[0005] The electrode slurry manufacturing device disclosed herein includes a material input machine, a feeder and a multi-axis kneading machine. The material input machine is configured to collectively input a plurality of electrode materials into the feeder. The feeder includes an input port, a stirring chamber, a discharge port, a conveying blade and a spiral blade. The electrode material is input from the material input machine to the input port. The electrode material is stirred in the stirring chamber. The discharge port is provided at the bottom of the stirring chamber. The electrode material is fed to the multi-axis kneading machine from the discharge port. The conveying blade is mounted on a shaft provided at the bottom of the stirring chamber. The conveying blade feeds the electrode material to the discharge port. The spiral blade is arranged above the conveying blade and mounted on the shaft. If based on this electrode slurry manufacturing device, the quality of electrode slurry manufactured using a plurality of electrode materials can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 This is a flow chart of a method for producing electrode slurry.

[0007] Figure 2 It is a schematic diagram of the electrode slurry production apparatus 10 .

[0008] Figure 3 It is a schematic diagram of the feeder 40.

[0009] Figure 4 It is a schematic diagram of a feeder 40A according to another embodiment.

[0010] Figure 5 It is a schematic diagram of a feeder 40B according to another embodiment.

[0011] Figure 6 It is a schematic diagram of a feeder 40C according to another embodiment.

[0012] Figure 7 It is a schematic diagram of a feeder 40D according to another embodiment. DETAILED DESCRIPTION

[0013] Below, one embodiment of the technology disclosed herein is described with reference to the accompanying drawings. Of course, the embodiments described herein are not intended to limit the present invention in any particular way. The drawings are schematic and do not necessarily reflect actual objects. Components and parts that perform the same function are appropriately labeled with the same reference numerals, and duplicate descriptions are omitted as appropriate.

[0014] <Battery Manufacturing Method>

[0015] Figure 1 This is a flow chart of the method for manufacturing electrode slurry. Figure 1 As shown, the method for manufacturing electrode slurry includes: step S1, in which a plurality of electrode materials are weighed with predetermined weights and fed into a feeder; step S3, in which the plurality of electrode materials are stirred in the feeder; step S5, in which the stirred plurality of electrode materials are fed to a multi-axis kneading machine; and step S7, in which the plurality of electrode materials are kneaded by the multi-axis kneading machine. The electrode slurry is prepared by using an electrode slurry manufacturing apparatus 10 (see Figure 2 ) to manufacture.

[0016] The electrode slurry manufacturing device and the electrode slurry manufacturing method disclosed herein can be applied to the electrode slurry manufacturing device and manufacturing method used in various power storage devices. Here, the so-called "power storage device" refers to the concept including a device that generates a charge and discharge reaction by moving a charge carrier between a pair of electrodes (a positive electrode and a negative electrode). The power storage device in the technology disclosed here includes capacitors such as lithium ion capacitors and double-layer capacitors in addition to secondary batteries such as lithium ion secondary batteries, nickel-metal hydride batteries, and nickel-cadmium batteries. Below, with respect to the technology disclosed here, the manufacturing device and manufacturing method of electrode slurry for lithium ion secondary batteries will be described as an example.

[0017] <Electrode Slurry Manufacturing Apparatus 10>

[0018] Figure 2 FIG. 1 is a schematic diagram of an electrode slurry manufacturing apparatus 10. Figure 2In the embodiment, the direction of supplying or conveying the material is indicated by an arrow. In the electrode slurry manufacturing device 10, the electrode composite material slurry is manufactured by kneading the electrode material and the solvent. In this embodiment, in the electrode slurry manufacturing device 10, the positive electrode composite material slurry including the positive electrode composite material is manufactured. Figure 2 As shown, the electrode slurry production apparatus 10 includes a material feeder 20 , a material input device 30 , a feeder 40 , and a multi-screw kneading machine 50 .

[0019] First, a plurality of electrode materials A to C are weighed to predetermined weights in the material feeder 20 , and are then fed into the feeder 40 via the material feeder 30 ( S1 ).

[0020] <Material Feeder 20>

[0021] The material feeder 20 includes feeders 21 to 23 and weighing machines 27 to 29. Powdered electrode materials A to C are fed from the feeders 21 to 23, respectively. Known devices capable of feeding a constant amount of powdered material can be used as the feeders 21 to 23. Examples of the feeders 21 to 23 include circulating feeders, screw feeders, rotary feeders, and belt feeders.

[0022] The feeders 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 size of 4 μm and a tap density of 2.2 g / cm 3 The electrode material C has an average particle size of 17 μm and a tap density of 2.4 g / cm 3 The electrode material B is contained in the feeder 22. In this embodiment, the electrode material B is polyvinylidene fluoride (PVDF) as a binder. Here, the electrode material B has a density of 1 g / cm 3 of PVDF.

[0023] In addition, the positive electrode active material and the binder are not particularly limited, and various materials that have been used as positive electrode active materials and binders for lithium ion secondary batteries can be used without particular restrictions. For example, as the positive electrode active material, lithium nickel oxide (such as LiNiO2), lithium cobalt oxide (such as LiCoO2), lithium manganese oxide (such as LiMn2O4), and their composites (such as LiNiO2) can be used. 0.5 Mn 1.5 O4、LiNi 1 / 3 Co 1 / 3 Mn 1 / 3O2) and other particles containing lithium and transition metal elements as oxides (lithium transition metal oxides) of the constituent metal elements, lithium manganese phosphate (LiMnPO4), lithium iron phosphate (LiFePO4) and other particles containing lithium and transition metal elements as phosphates of the constituent metal elements, etc. As binders, for example, acrylic resins such as (meth)acrylate polymers, halogenated vinyl resins such as polyvinylidene fluoride (PVDF), polyalkylene oxides such as polyethylene oxide (PEO), etc. can be used. In addition, from the viewpoint of ease of stirring and kneading in subsequent steps, it is preferred that the density (or tap density) of the electrode material of the powder supplied from the supply machine is 0.5 to 3.0 g / cm 3 .

[0024] The weighing machines 27 to 29 are devices for weighing the electrode materials A to C supplied from the feeders 21 to 23. The weighing machines 27 to 29 are respectively provided with containers 31 for placing the electrode materials A to C supplied from the feeders 21 to 23. The containers 31 are arranged on the indexing table 25. A plurality of containers (in the indexing table 25) can be arranged. Figure 2 In the embodiment shown, there are six containers 31. The indexing table 25 is driven and rotated by the drive device 25b connected to the shaft 25a in a predetermined direction and at a predetermined timing. By rotating the indexing table 25, the containers 31 are sequentially moved to the positions where the electrode materials A to C are supplied from the feeders 21 to 23. At this time, the weights of the electrode materials A to C supplied to the containers 31 are weighed by the weighing machines 27 to 29, respectively. When the container 31 moves to the position where the electrode materials A to C are supplied, the other containers 31 are also moved in the same direction and at the same timing. If material is supplied to one container 31, the material is also supplied sequentially to the other containers 31 that are connected to the container 31.

[0025] In weighing machines 27 to 29, electrode materials A to C are weighed to predetermined weights respectively. As weighing machines 27 to 29, for example, a scale, a load cell, etc. can be used. First, container 31 is moved to the position where electrode material A is supplied. Container 31 is placed on weighing machine 27. The weight of electrode material A supplied from supplier 21 to container 31 is weighed by weighing machine 27. Next, container 31 is moved to the position where electrode material B is supplied. Container 31 is placed on weighing machine 28. The weight of electrode material B supplied from supplier 22 to container 31 is weighed by weighing machine 28. Next, container 31 is moved to the position where electrode material C is supplied. Container 31 is placed on weighing machine 29. The weight of electrode material C supplied from supplier 23 to container 31 is weighed by weighing machine 29.

[0026] The weight of the electrode materials A-C weighed by the weighing machines 27-29 is appropriately set according to the target composition of the electrode composite material slurry. The weight ratio of the positive electrode active material, binder, and conductive material contained in the positive electrode composite material slurry can be set, for example, to about 96.0-99.0:0.5-2.0:0.5-2.0. In this embodiment, the weight ratio of the positive electrode active material, binder, and conductive material contained in the positive electrode composite material slurry is set to 97.5:1.0:1.5. The weighing machines 27-29 are used to weigh the electrode materials A-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) is 48.75:1.0:48.75. In addition, in this embodiment, acetylene black (AB) can be used as the conductive material. Acetylene black as a conductive material is placed in a paste state in a multi-screw kneading machine 50 to be described later.

[0027] 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. In container 31, electrode material A (positive electrode active material), electrode material B (binder), and electrode material C (positive electrode active material) are placed in order from the bottom toward the opening of container 31. In step S1 of placing the positive electrode active material in container 31, after the positive electrode active material with a relatively high density is placed in container 31, the binder with a relatively low density is placed in container 31, and then the positive electrode active material with a relatively high density is placed in container 31.

[0028] The method for placing electrode materials A-C into material feeder 30 is not particularly limited. For example, electrode materials A-C may be weighed in separate containers and then placed into container 31. Furthermore, the order in which electrode materials A-C are placed into container 31 is not limited to the above. For example, electrode material C, electrode material B, and electrode material A may be placed into container 31 in that order. The order in which the materials are placed into container 31 can also be appropriately determined based on the physical properties and quantity of the materials.

[0029] Material feeding machine 30

[0030] The material feeder 30 is configured to collectively feed a plurality of electrode materials A to C into the feeder 40. In this embodiment, a reversing feeder can be used as the material feeder 30, which feeds the electrode materials A to C into the feeder 40 by reversing the container 31. Hereinafter, the material feeder 30 will also be referred to as the reversing feeder 30. Furthermore, the material feeder 30 is not limited to the reversing feeder 30; conventionally known material feeders can be used. Alternatively, a circulating feeder, a screw feeder, a rotary feeder, a belt feeder, or the like can be used as the material feeder 30.

[0031] The reverse feeding machine 30 includes an arm 32 and a drive device 33. The arm 32 is configured to grip the container 31. The drive device 33 drives the arm 32 using a fulcrum 32a set on the arm 32 as an axis. The drive device 33 can be implemented by, for example, a motor, a sprocket, or the like.

[0032] In this embodiment, the driving device 33 rotates the arm 32 toward the feeder 40 using the fulcrum 32a as an axis. The driving device 33 stops the arm 32 after rotating it about 180 degrees. Figure 2 The position of the inverting feeding machine 30 and the feeding machine 40 is set so that the container 31 is in the stirring chamber 41 of the feeding machine 40 (refer to Figure 3 ) is inverted above the mixing chamber 41. An inlet 41a for material input is provided at the upper portion of the mixing chamber 41 (see Figure 3 ). Electrode materials A to C fall from the inverted container 31 and are introduced into the stirring chamber 41 from the inlet 41a. Electrode material C, electrode material B, and electrode material A are introduced from the container 31 into the stirring chamber 41 in this order. Furthermore, when introducing electrode materials A to C into the feeder 40, a device other than the inverting feeder 30 may be used. For example, a lifting and reversing feeder may be used that raises and lowers the container along a lifting axis and then inverts it.

[0033] After electrode materials A-C are placed in the feeder 40, the drive device 33 drives the arm 32 in the opposite direction, returning the container 31 to the indexing table 25. The indexing table 25 then rotates, moving the container 31. At this point, a new container 31 containing weighed electrode materials A-C is fed to the reversing feeder 30. By repeating this process, the container 31 containing electrode materials A-C is fed to the reversing feeder 30 at regular intervals.

[0034] Electrode materials A-C are intermittently fed into the feeder 40 via the reversing feeder 30. The weighing of the electrode materials A-C by the material feeder 20 and the reversing feeding of the electrode materials A-C by the reversing feeder 30 can be performed in tandem. In this embodiment, the steps of feeding the electrode materials A-C into the container 31 of the reversing feeder 30 and reversing the feeding from the reversing feeder 30 to the feeder 40 are repeated in a cycle of approximately 30 seconds. Therefore, a substantially constant amount of electrode materials A-C is fed into the feeder 40 at substantially constant intervals. In other words, step S1 of weighing the electrode materials A-C and feeding them into the feeder 40 is repeated at substantially constant intervals. Electrode materials A-C having an adjusted weight ratio can be fed into the feeder 40 at predetermined intervals. Since the electrode materials A-C are weighed each time they are fed into the feeder 40, the weight ratio of the electrode materials A-C within the feeder 40 is easily stabilized. Even when a plurality of electrode materials A to C are used, it is easy to ensure the mixing ratio of the mixed powder material fed into the feeder 40 .

[0035] In the feeder 40 , the electrode materials A to C put into the feeder 40 are stirred ( S3 ).

[0036] <Supply machine 40>

[0037] Figure 3 Schematic diagram of the feeder 40. Figure 3 In FIG, arrows are used to indicate the direction in which the electrode materials A to C are transported and the direction in which the spiral blade 45 rotates. Figure 3 , a schematic cross-section of the feeder 40 along the height direction is shown. In this embodiment, a quantitative feeder (hereinafter referred to as the feeder 40) that continuously supplies a predetermined amount of material can be used as the feeder 40. In this embodiment, the feeder 40 is a so-called circulating feeder. By using a circulating feeder as the feeder 40, the supply amount of electrode materials A to C can be stabilized, and the equipment can be miniaturized.

[0038] like Figure 3 As shown, the feeder 40 includes an inlet 41a, a stirring chamber 41, a discharge port 41b1, conveying blades 43 and 44, and a spiral blade 45. The inlet 41a and the discharge port 41b1 are provided in the stirring chamber 41. Electrode materials A to C are fed into the inlet 41a from the material feeder 30. Electrode materials A to C are stirred in the stirring chamber 41. After being stirred in the stirring chamber 41, the electrode materials A to C are discharged from the discharge port 41b1 to the multi-screw kneading machine 50.

[0039] <Mixing chamber 41>

[0040] The stirring chamber 41 is formed in a roughly cylindrical shape. The upper part of the stirring chamber 41 is open and has an inlet 41a for feeding the electrode materials A to C. The stirring chamber 41 has a roughly disc-shaped bottom 41b. A discharge port 41b1 is formed in a portion of the bottom 41b. The stirring chamber 41 is connected to the quantitative supply chamber 42 via the discharge port 41b1. An intermediate plate 41c is provided above the discharge port 41b1. The intermediate plate 41c is roughly disc-shaped except for the opening 41c1 formed in a portion. The intermediate plate 41c is sized to cover at least the upper portion of the discharge port 41b1. The opening 41c1 of the intermediate plate 41c and the discharge port 41b1 of the bottom 41b are formed in different positions when viewed from above. The opening 41c1 of the intermediate plate 41c and the discharge port 41b1 of the bottom 41b are provided on opposite sides with the shaft 46 provided in the roughly central portion of the bottom 41b interposed therebetween.

[0041] <Conveying blades 43, 44>

[0042] Conveying blades 43 and 44 convey electrode materials A-C toward discharge port 41b1. Conveying blades 43 and 44 are attached to shaft 46. Conveying blades 43 and 44 rotate in response to the rotation of shaft 46. Shaft 46 consists of a lower portion 46a and an upper portion 46b. Both lower portion 46a and upper portion 46b of shaft 46 are roughly cylindrical. The diameter of lower portion 46a is larger than that of upper portion 46b, and lower portion 46a is shorter than upper portion 46b. Shaft 46 is mounted on bottom portion 41b and extends upward from approximately the center of bottom portion 41b.

[0043] The conveying blades 43 and 44 are roughly rod-shaped components. They extend radially outward from the shaft 46. The conveying blade 43 is located below the intermediate plate 41c. The conveying blade 44 is located above the intermediate plate 41c. In other words, the conveying blades 43 and 44 are located so as to sandwich the intermediate plate 41c. The conveying blades 43 extend along the upper surface of the bottom 41b. Four conveying blades 43 extend from the lower portion 46a of the shaft 46 below the intermediate plate 41c. The four conveying blades 43 are arranged at approximately equal intervals around the circumference of the shaft 46. The conveying blades 44 extend along the upper surface of the intermediate plate 41c. Two conveying blades 44 extend in opposite directions from the lower portion 46a of the shaft 46 above the intermediate plate 41c. A drive device 47 is connected to the shaft 46. The drive device 47 is, for example, a motor. The drive device 47 may also be connected to the shaft 46 via a speed reducer, a transmission, or the like. The shaft 46 is driven and rotated by the driving device 47 , thereby rotating the conveying blades 43 and 44 .

[0044] Spiral blade 45

[0045] The spiral blade 45 stirs the electrode materials A to C within the stirring chamber 41. The spiral blade 45 is attached to the upper portion 46b of the shaft 46. The spiral blade 45 rotates in response to the rotation of the shaft 46. The spiral blade 45 is arranged above the conveying blade 43, which is attached to the lower portion 46a of the shaft 46. The shaft 46 is rotated by the drive device 47, so that the conveying blades 43 and 44 and the spiral blade 45 rotate in the same direction and at the same speed along the circumference of the shaft 46. The "spiral blade 45" is a component that is wound in a predetermined direction along the circumference and height of the shaft 46.

[0046] 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 circumference of the shaft 46 in the radial direction of the shaft 46. The spiral blade 45 is a so-called spiral blade. The spiral blade 45 is wound twice clockwise from the base end to the tip. The outer edge of the spiral blade 45 is radially spaced apart from the inner circumference of the stirring chamber 41 by a substantially constant gap. This gap is set to a size that allows the electrode materials A to C to pass through.

[0047] The spiral blade 45 has a plurality of holes 45a formed therein. The holes 45a are sized to allow the electrode materials A to C to pass through. The size of the holes 45a is not particularly limited, but the inner diameter or the interval between the narrowest parts can be set to 1 mm or greater, and for example, preferably 3 mm or greater. The size of the holes 45a is not particularly limited, but the inner diameter or the interval between the narrowest parts can be set to 20 mm or less, and for example, preferably 10 mm or less.

[0048] The hole 45a is a long hole along the radial direction of the shaft 46. The shape of the hole 45a is not particularly limited. In this embodiment, the outer shape of the hole 45a is an approximate elliptical shape consisting of a pair of parallel straight lines and an arc-shaped line connecting the pair of parallel straight lines. In addition, the shape of the hole 45a is not limited to such an elliptical shape, and can be a polygon such as a rectangle, or a standard ellipse. Although not particularly limited, it is preferred that the ratio of the major diameter to the minor diameter of the hole 45a (aspect ratio) is greater than 1, and is greater than 2. The ratio of the major diameter to the minor diameter of the hole 45a can also be less than 10, preferably less than 7. In addition, the hole 45a is not necessarily a long hole, and can be a circle, or a regular polygon such as a square.

[0049] Multiple holes 45a are intermittently formed along the winding direction of the spiral blade 45. The multiple holes 45a are of approximately the same size and shape and are formed at approximately constant intervals. The multiple holes 45a are formed radially close to the outer edge of the spiral blade 45. The holes 45a are located outside the middle portion in the width direction of the spiral blade 45 (radially of the shaft 46). The center of the hole 45a is located outside the middle portion in the width direction of the spiral blade 45.

[0050] The electrode materials A to C are stirred in the feeder 40 . Hereinafter, the supply of the electrode materials A to C to the feeder 40 and the stirring in the feeder 40 will be described.

[0051] By inverting the container 31 above the stirring chamber 41 , the electrode materials A to C introduced from the introduction port 41 a are introduced into the feeder 40 in the reverse order of the introduction into the container 31 (in this embodiment, in the order of electrode materials C, B, A).

[0052] Inside the stirring chamber 41 of the feeder 40, conveying blades 43, 44, and a spiral blade 45 rotate in response to the rotation of a shaft 46 by a drive device 47. The conveying blades 43, 44, and the spiral blade 45 rotate counterclockwise (in the opposite direction to the direction in which the spiral blade 45 winds from the bottom to the front). When electrode materials A-C are added to the stirring chamber 41, they collide with the rotating spiral blade 45 and accumulate within the stirring chamber 41.

[0053] A portion of the electrode materials A-C accumulates below the upper end of the conveying blade 44. The electrode materials A-C accumulated below the upper end of the conveying blade 44 are conveyed toward the opening 41c1 by the conveying blade 44. The conveyed electrode materials A-C fall downward from the opening 41c1 and accumulate at the bottom 41b. The electrode materials A-C accumulated at the bottom 41b are conveyed toward the discharge port 41b1 by the conveying blade 43. The conveyed electrode materials A-C are discharged from the discharge port 41b1.

[0054] A portion of the electrode materials A-C accumulates at a position higher than the conveying blade 44. The electrode materials A-C accumulated at a position higher than the conveying blade 44 are stirred along the rotational direction of the rotating spiral blade 45. Furthermore, the rotating spiral blade 45 can lift a portion of the electrode materials A-C upward. The lifted electrode materials A-C fall downward through the hole 45a formed in the spiral blade 45 or from the outer edge of the spiral blade 45. This also allows the electrode materials A-C to be stirred in the vertical direction.

[0055] If the electrode materials A-C that have fallen down accumulate at a position higher than the conveying blades 44, they can be lifted up again by the spiral blades 45 and stirred. If the electrode materials A-C that have fallen down accumulate below the upper end of the conveying blades 44, they are conveyed toward the opening 41c1 by the conveying blades 44. Next, the electrode materials A-C are conveyed toward the discharge port 41b1 by the conveying blades 43. In this way, while the spiral blades 45 stir the electrode materials A-C, the conveying blades 43 and 44 discharge the electrode materials A-C from the discharge port 41b1 in a substantially constant amount.

[0056] The electrode materials A to C are intermittently fed in by the material feeder 30. The electrode materials A to C fed in from the material feeder 30 can be accumulated on the electrode materials A to C already accumulated in the stirring chamber 41. Therefore, the newly fed electrode materials A to C are stirred by the spiral blade 45 and discharged in sequence 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 can be stored in the stirring chamber 41. Thus, the stirring efficiency of the electrode materials A to C can be improved. As described above, in the stirring chamber 41, the feeding of the electrode materials A to C by the material feeder 30, the stirring of the electrode materials A to C by the spiral blade 45, and the discharge of the electrode materials A to C from the discharge port 41b1 are performed in sequence.

[0057] In this embodiment, a metering chamber 42 is connected to the discharge port 41b1 of the stirring chamber 41. The metering chamber 42 is generally cylindrical and lower than the stirring chamber 41. Conveying blades 42a are provided in the metering chamber 42. The conveying blades 42a are attached to a shaft 42b. The shaft 42b extends upward from approximately the center of the bottom 42c. The conveying blades 42a extend radially outward from the shaft 42b, curving along the bottom 42c. This shape of the conveying blades 42a facilitates stable transport of the electrode materials A-C. The height of the conveying blades 42a decreases as they move radially outward. In this embodiment, four conveying blades 42a extend from the shaft 42b. The shape and number of the conveying blades 42a are not particularly limited and can be appropriately set according to the type of material. A drive device 47 is connected to the shaft 42b. Therefore, the conveying blades 42a rotate at the same timing as the conveying blades 43, 44, and the spiral blade 45. A discharge port 42c1 is formed in the bottom portion 42c of the quantitative supply chamber 42. In addition, the quantitative supply chamber 42 does not necessarily need to be provided.

[0058] The amount of electrode materials A to C discharged from discharge port 42c1 is set by the rotational speed of conveying blades 42a, 43, and 44. By driving conveying blades 42a, 43, and 44 at a constant speed using a drive device 47, a substantially constant amount of electrode materials A to C can be continuously discharged from discharge port 42c1. The rotational speed of conveying blades 42a, 43, and 44 is not particularly limited but can be appropriately set based on the interval and amount of electrode materials A to C that are reversely fed.

[0059] The stirred electrode materials A to C are discharged from the discharge port 41 b 1 of the feeder 40 and supplied to the multi-screw kneading machine 50 ( S5 ).

[0060] Multi-shaft Kneader 50

[0061] Multi-screw mixer 50 (refer to Figure 2 ) is a device for kneading the electrode materials A to C by applying shear force. The electrode materials A to C are kneaded while being conveyed along the conveying direction in the multi-axis kneading machine 50. Figure 2 As shown, the multi-screw kneading machine 50 includes a barrel 51, a shaft 52 disposed in the barrel 51, and a drive device 53 for driving the shaft 52. In this embodiment, a twin-screw kneading machine 50 having two shafts 52 extending substantially parallel to each other in the barrel 51 can be used as the multi-screw kneading machine 50. The twin-screw kneading machine 50 may be provided with a thermometer for measuring the temperature of the material in the barrel 51, a cooling device for adjusting the temperature of the material in the barrel 51, and the like. The device for kneading the electrode material is not limited to a twin-screw kneading machine, and may be a multi-screw kneading machine such as a four-screw kneading machine.

[0062] The barrel 51 is cylindrical and has a space inside for placing electrode materials, solvents, etc. A powder supply port 51a for supplying electrode materials A to C is provided at one end of the barrel 51. The powder supply port 51a is connected to the discharge port 41b1 of the feeder 40. In this embodiment, the powder supply port 51a is connected to the discharge port 41b1 via the discharge port 42c1 of the quantitative 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 Mono pump for maintaining a constant discharge volume may also be connected to the solvent supply device 55. A constant discharge volume of solvent is continuously supplied from the solvent supply port 51b. As the solvent, for example, water, N-methyl-2-pyrrolidone (NMP), etc. can be used. 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 Mono pump for making the discharge volume constant can also be connected to the paste supply device 56. A flow meter for measuring the flow rate of the supplied solvent and paste can also be provided on the Mono pump. In order to stabilize the discharge volume, the rotation of the Mono pump rotor can also be controlled according to the flow rate measured by the flow meter. A constant discharge volume of paste is continuously supplied from the paste inlet 51c. In this embodiment, a paste-like conductive material (acetylene black in this embodiment) is added from the paste inlet 51c. In this way, the materials of the positive electrode composite material slurry are supplied to the barrel 51 in the order of electrode materials A to C, solvent, and conductive material. A discharge port 51d is provided downstream of the paste inlet 51c. The discharge port 51d is provided at the end of the barrel 51 on the opposite side of the powder supply port 51a. The prepared positive electrode composite material slurry is discharged from the discharge port 51d.

[0063] A shaft 52 extending in the conveying direction is provided in the barrel 51. A screw 52a and a stirring blade 52b are provided on the shaft 52. A plurality of screws 52a and stirring blades 52b are provided along the conveying direction. The screw 52a and stirring blades 52b are provided on the outer peripheral surface of the shaft 52. The screw 52a has blades wound into a spiral shape. The stirring blade 52b is a plate-shaped component with its width facing the conveying direction. Although not particularly limited, the stirring blade 52b is a polygon (such as a triangle, a quadrilateral, a hexagon, etc.) with its corners formed into a curved shape. The side circumference of the stirring blade 52b can also be formed into a curved shape. A predetermined gap is formed between the side circumference of the stirring blade 52b and the inner circumference of the barrel 51.

[0064] The driving device 53 can be a motor or the like that drives the shaft 52 to rotate. As the shaft 52 rotates, the screw 52a and the stirring blade 52b rotate along the circumferential direction of the shaft 52. The material in the barrel 51 is pressed by the blades of the screw 52a and conveyed along the conveying direction. A shear force is applied to the material in the barrel 51 between the side circumferential surface of the stirring blade 52b and the inner circumferential surface of the barrel 51. The twin-screw kneading machine 50 can also be provided with a pressure gauge that measures the pressure in the barrel 51. The driving of the driving device 53 can also be controlled by making the pressure in the barrel 51 measured by the pressure gauge fall within a required pressure range.

[0065] The electrode materials A to C are kneaded using the above-mentioned biaxial kneading machine 50 ( S7 ).

[0066] The electrode materials A to C stirred in the feeder 40 are fed from the powder feed port 51a into the barrel 51 of the twin-screw kneader 50. The feeder 40 continuously feeds a substantially constant amount of the electrode materials A to C into the barrel 51 per unit time.

[0067] The electrode materials A-C are conveyed in the conveying direction by the screw 52a. As the electrode materials A-C pass between the side circumference of the stirring blade 52b and the inner circumference of the barrel 51, they are conveyed while being subjected to shear force. The electrode materials A-C conveyed within the barrel 51 are mixed with the solvent supplied from the solvent supply port 51b. The solvent is introduced into the barrel 51 separately from multiple solvent supply ports 51b arranged along the conveying direction. This allows the electrode materials A-C and the solvent to be mixed in stages. This minimizes unevenness within the kneaded materials. The materials conveyed within the barrel 51 (here, the electrode materials A-C and the solvent) are mixed with a paste-like conductive material. The paste-like conductive material enters the barrel 51 from the paste inlet 51c. By kneading and conveying the electrode materials A-C, the solvent, and the conductive material, a positive electrode composite material slurry is produced. The produced positive electrode composite material slurry is discharged from the discharge port 51d.

[0068] The battery can be manufactured using the manufactured positive electrode composite material slurry by a known method. For example, the positive electrode composite material slurry is applied to both sides of the positive electrode collector and dried. By cutting it into a specified size and rolling it using a roller press, a positive electrode sheet having a positive electrode active material layer on both sides of the positive electrode collector is prepared. A negative electrode composite material slurry is manufactured, and a negative electrode sheet having a negative electrode active material is prepared in the same order as the order in which the positive electrode sheet is prepared. The positive electrode sheet and the negative electrode sheet are stacked via a separator sheet to form an electrode body. The electrode body is housed in a battery case to form a battery assembly. An electrolyte is injected into the battery assembly, and an initial charge and an aging treatment are performed to manufacture the battery.

[0069] However, the electrode slurry (electrode composite material slurry) used for the electrode contains a variety of electrode materials. A high shear force is applied to the various electrode materials in a multi-axis mixer while they are kneaded. Next, the mixed electrode material is diluted in a solvent or the like to disperse it. However, the various electrode materials differ in the physical properties of the material, such as specific gravity, particle size, viscosity, etc. In addition, there are cases where the electrode materials contain materials that are difficult to disperse evenly in solvents or the like. Examples of materials that are difficult to disperse evenly include adhesives, thickeners, etc. In the case of containing electrode materials with different physical properties, when it is in a case where it contains electrode materials with poor dispersibility, the material becomes uneven in the multi-axis mixer. In this case, the material may also become uneven in the prepared electrode slurry. In this case, when the electrode slurry is coated as an electrode composite material, it will also be uneven, which may make the quality of the electrode unstable.

[0070] In the above embodiment, the electrode slurry production apparatus 10 includes a material feeder 30, a feeder 40, and a multi-shaft kneading machine 50. The material feeder 30 is configured to collectively feed a plurality of electrode materials A to C into the feeder 40. The feeder 40 includes an inlet 41a, a stirring chamber 41, a discharge port 41b1, conveying blades 43 and 44, and a spiral blade 45. Electrode materials A to C are fed from the material feeder 30 into the inlet 41a. Electrode materials A to C are stirred in the stirring chamber 41. The discharge port 41b1 is provided at the bottom 41b of the stirring chamber 41. Electrode materials A to C are fed from the discharge port 41b1 to the multi-shaft kneading machine 50. The conveying blades 43 and 44 are attached to a shaft 46 provided at the bottom 41b of the stirring chamber 41. The conveying blades 43 and 44 feed the electrode materials A to C toward the discharge port 41b1. The spiral blade 45 is disposed above the conveying blades 43 and 44 and attached to the shaft 46.

[0071] According to the electrode slurry manufacturing apparatus 10, electrode materials A-C introduced into the stirring chamber 41 are stirred by the spiral blades 45 while being discharged from the discharge port 41b1 by the conveying blades 43 and 44, thereby being conveyed to the multi-shaft kneading machine 50. During stirring, the electrode materials A-C are stirred along the rotational direction of the rotating spiral blades 45. Furthermore, the electrode materials A-C can be lifted by the spiral blades 45 or dropped from the spiral blades 45. This allows the electrode materials A-C to be stirred in the vertical direction. Thus, within the stirring chamber 41, the electrode materials A-C can be stirred in both the rotational direction of the spiral blades 45 and the vertical direction. This improves the uniformity of the electrode materials A-C within the stirring chamber 41. By supplying highly uniform electrode materials A-C to the multi-shaft kneading machine 50, uniform shear force can be easily applied to the electrode materials A-C within the multi-shaft kneading machine 50. The electrode materials A to C can be well dispersed in the multi-screw kneading machine 50. As a result, the electrode materials A to C can be well dispersed in the electrode slurry, and the quality of the electrode can be stabilized.

[0072] In the above embodiment, the spiral blades 45 are connected to the shaft 46 in the radial direction of the shaft 46. The lifted electrode materials A-C are easily dropped from the outer edge of the spiral blades 45. This facilitates the electrode materials A-C to circulate along the path where they are lifted and drop outward from the outer edge of the spiral blades 45. As a result, the electrode materials A-C are more easily stirred in the vertical direction.

[0073] In the above embodiment, the spiral blade 45 is formed with a plurality of holes 45a through which the electrode materials A-C pass. The lifted electrode materials A-C fall not only from around the spiral blade 45 but also from the holes 45a. The location where the lifted electrode materials A-C fall can be set by additional means, making it easier to stir the electrode materials A-C.

[0074] In the above embodiment, multiple holes 45a are intermittently formed along the winding direction of the spiral blade 45. The multiple holes 45a are intermittently arranged at different heights. This allows electrode materials A-C to fall through holes 45a at various heights. As a result, electrode materials A-C are more easily stirred.

[0075] In the above embodiment, the hole 45a is an elongated hole extending radially along the shaft 46. Since the hole 45a extends radially along the shaft 46, the electrode materials A to C lifted by the spiral blades 45 easily fall through the hole 45a. This facilitates stirring of the electrode materials A to C.

[0076] In the above embodiment, the plurality of electrode materials A to C include a first electrode material (PVDF as electrode material B in this embodiment) and a second electrode material having a greater density than the first electrode material (the positive electrode active material as electrode materials A and C in this embodiment). In the step of placing the electrode materials in container 31, after a portion of the second electrode material (electrode material A) is placed in container 31, the first electrode material (electrode material B) is placed in container 31, and then the remaining portion of the second electrode material (electrode material C) is placed in container 31. Within container 31, electrode material B, which has a relatively low density, is sandwiched between electrode materials A and C, which have relatively high densities. This reduces the amount of electrode material B that splashes when electrode materials A to C are added to container 31 and when they are added from container 31 to feeder 40. As a result, the weight ratio of electrode materials A to C supplied to the twin-screw kneading machine 50 can be easily stabilized.

[0077] Here, a method for producing a positive electrode composite material slurry is described as an example, but the present invention is not limited to this embodiment. The electrode slurry production apparatus 10 can also produce a negative electrode composite material slurry.

[0078] The negative electrode composite material slurry may contain, for example, a negative electrode active material, a thickener, and a binder. The materials contained in the negative electrode composite material slurry are not particularly limited, and various materials that have been used as materials for lithium-ion secondary batteries in the past can be used without particular restrictions. As the negative electrode active material, for example, carbon materials represented by artificial graphite, natural graphite, amorphous carbon, and composites thereof (for example, amorphous carbon-coated graphite) or materials that form alloys with lithium, such as silicon (Si), and lithium storage compounds such as silicon compounds (SiO, etc.) can be used. As a thickener, for example, carboxymethyl cellulose (CMC) can be used. As a binder, for example, styrene-butadiene rubber (SBR) can be used. The weight ratio of the negative electrode active material, thickener, and binder contained in the negative electrode composite material slurry can be set to, for example, negative electrode active material: thickener: binder = 96.0 to 99.0: 0.5 to 2.0: 0.5 to 2.0.

[0079] When producing the negative electrode composite material slurry, the negative electrode active material and CMC as a thickener can be placed in container 31. Similar to the acetylene black paste used in producing the positive electrode composite material slurry, SBR as a binder can be added through the paste inlet 51c. The process for producing the negative electrode composite material slurry is the same as that for producing the positive electrode composite material slurry, so a detailed description will be omitted.

[0080] In addition, the structure of the feeder 40 is not limited to the above-mentioned embodiment. Figures 4 to 7 Schematic diagram of the feeder 40A to 40D according to another embodiment. Figures 4 to 7The spiral blades 45A to 45D of the feeders 40A to 40D shown in FIG. 4 are formed with holes 45a (see FIG. Figure 3 ).

[0081] exist Figure 4 In the feeder 40A shown, two spiral blades 45A are wound around a shaft 46. The two spiral blades 45A are symmetrical with respect to the shaft 46. The two spiral blades 45A are each wound around the shaft 46 for approximately 1.5 turns. Figure 5 In the illustrated feeder 40B, two spiral blades 45B are each wound approximately once around a shaft 46. The feeder 40B has the same structure as the feeder 40A, except that the two spiral blades 45B are wound approximately once. Thus, the number of turns of the spiral blades wound around the shaft 46 and the number of blades per unit length are not particularly limited and can be appropriately set depending on the structure of the electrode materials A to C, etc.

[0082] exist Figure 6 In the feeder 40C shown, two spiral blades 45C are wound around the shaft 46. The spiral blade 45C is in the shape of a belt wound around the shaft 46 at a substantially constant interval except for the base end and the upper end. The spiral blade 45C has an upper surface on which the electrode materials A to C are placed. The spiral blade 45C is connected to a rod-shaped member extending from the shaft 46 at the base end and the upper end of the shaft 46. Thus, the shaft 46 and the spiral blade 45C are supported with a gap therebetween. The two spiral blades 45C are symmetrical with respect to the shaft 46. The two spiral blades 45C are each wound about 1.5 turns around the shaft 46. 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). In Figure 7 In the illustrated feeder 40D, two spiral blades 45D are each wound approximately once around a shaft 46. The feeder 40D has the same structure as the feeder 40C, except that the two spiral blades 45D are wound approximately once. Thus, gaps may be formed around the shaft 46 and the spiral blades.

[0083] According to the experiments conducted by the inventors, it was found that the fewer the number of spiral blades, the easier it is to stir the electrode material with a small particle size, and the more the number of spiral blades, the easier it is to stir the electrode material with a large particle size. In addition, it was found that the fewer the number of turns of the spiral blade, the easier it is to stir the electrode material with a small particle size, and the more the number of turns of the spiral blade, the easier it is to stir the electrode material with a large particle size. In addition, it was found that when the particle size of the electrode material is small, if a gap is formed between the shaft and the spiral blade, the electrode material is easy to stir. In the case of manufacturing the positive electrode composite material slurry of the above embodiment, among the feeders 40A to 40D, it was found that when the feeder 40A was used, the electrode materials A to C were easy to diffuse.

[0084] The above descriptions of the technology disclosed herein are various. Unless otherwise specified, the embodiments and the like cited herein do not limit the present invention. In addition, the technology disclosed herein can be modified in various ways. Unless special problems arise, the various components and the various processes mentioned herein can be appropriately omitted or appropriately combined. In addition, this specification includes the disclosures described in the following items.

[0085] Item 1:

[0086] An electrode slurry manufacturing device, comprising:

[0087] Material feeding machine;

[0088] a feeder; and

[0089] Multi-shaft mixer,

[0090] The material feeding mechanism is configured to feed a plurality of electrode materials into the feeding machine in a centralized manner.

[0091] The above-mentioned feeding machine has:

[0092] An input port, the input port being used to input the electrode material from the material input machine;

[0093] A stirring chamber, which is used to stir the electrode material;

[0094] a discharge port, the discharge port being provided at the bottom of the stirring chamber and being used for delivering the electrode material to the multi-shaft kneading machine;

[0095] a conveying blade attached to a shaft provided at the bottom of the stirring chamber and configured to convey the electrode material to the discharge port; and

[0096] A spiral blade is arranged on the conveying blade and mounted on the shaft.

[0097] Item 2:

[0098] In the electrode slurry production apparatus described in Item 1,

[0099] The spiral blades are connected to the shaft in a radial direction of the shaft.

[0100] Item 3:

[0101] In the electrode slurry production apparatus according to item 1 or 2,

[0102] The spiral blades are formed with a plurality of holes through which the electrode material passes.

[0103] Item 4:

[0104] In the electrode slurry production device described in item 3,

[0105] The plurality of holes are intermittently formed along a winding direction of the spiral blade.

[0106] Item 5:

[0107] In the electrode slurry production apparatus according to item 3 or 4,

[0108] The hole is an elongated hole extending in the radial direction of the shaft.

[0109] Item 6:

[0110] A method for producing an electrode slurry, comprising the following steps:

[0111] Weighing a plurality of electrode materials to predetermined weights, and feeding them into a feeder;

[0112] Stirring the plurality of electrode materials in the feeder;

[0113] supplying the stirred plurality of electrode materials to a multi-screw kneader; and

[0114] The above-mentioned multiple electrode materials are mixed using the multi-axis mixer.

[0115] The above-mentioned feeding machine has:

[0116] An input port, which is used to input the electrode material from a material input machine;

[0117] A stirring chamber, which is used to stir the electrode material;

[0118] a discharge port, the discharge port being provided at the bottom of the stirring chamber and being used for delivering the electrode material to the multi-shaft kneading machine;

[0119] a conveying blade attached to a shaft provided at the bottom of the stirring chamber and configured to convey the electrode material to the discharge port; and

[0120] A spiral blade is arranged on the conveying blade and mounted on the shaft.

Claims

1. An electrode slurry manufacturing device, characterized in that: have: Material feeding machine; a feeder; and Multi-shaft mixer, The material input mechanism is configured to collectively input a plurality of electrode materials into the feeder. The feeder comprises: An input port, the input port being used to input the electrode material from the material input machine; a stirring chamber, the stirring chamber being used to stir the electrode material; a discharge port, which is provided at the bottom of the stirring chamber and is used to deliver the electrode material to the multi-shaft mixer; a conveying blade mounted on a shaft provided at the bottom of the stirring chamber and configured to convey the electrode material to the discharge port; as well as A spiral blade is arranged on the conveying blade and mounted on the shaft.

2. The electrode slurry production device according to claim 1, characterized in that: The spiral blades are connected to the shaft in a radial direction of the shaft.

3. The electrode slurry production device according to claim 1 or 2, characterized in that: The spiral blades are formed with a plurality of holes through which the electrode material passes.

4. The electrode slurry production device according to claim 3, characterized in that: The plurality of holes are intermittently formed along a winding direction of the spiral blade.

5. The electrode slurry production device according to claim 3, characterized in that: The hole is an elongated hole extending in the radial direction of the shaft.

6. A method for producing an electrode slurry, characterized in that: The process includes the following steps, namely: Weighing a plurality of electrode materials to predetermined weights, and feeding them into a feeder; stirring the plurality of electrode materials in the feeder; supplying the stirred plurality of electrode materials to a multi-screw kneader; and The plurality of electrode materials are mixed using the multi-axis mixer, The feeder comprises: An input port, the input port being used to input the electrode material from a material input machine; a stirring chamber, the stirring chamber being used to stir the electrode material; a discharge port, which is provided at the bottom of the stirring chamber and is used to deliver the electrode material to the multi-shaft mixer; a conveying blade mounted on a shaft provided at the bottom of the stirring chamber and configured to convey the electrode material to the discharge port; as well as A spiral blade is arranged on the conveying blade and mounted on the shaft.

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