JP7272839B2 - Feeding device and method for manufacturing electrode for lithium ion battery - Google Patents

Description

The present invention relates to a feeding device and a method for manufacturing an electrode for a lithium ion battery.

In recent years, it is strongly desired to reduce carbon dioxide emissions for environmental protection. In the automotive industry, expectations are high for the introduction of electric vehicles (EV) and hybrid electric vehicles (HEV) to reduce carbon dioxide emissions. It is done. As a secondary battery, attention is focused on a lithium ion battery (also called a lithium ion secondary battery) capable of achieving high energy density and high output density.

An electrode used in a lithium ion battery has an active material layer containing an active material on a current collector, and a homogeneous active material layer is formed to exhibit stable battery performance. This active material layer is produced by supplying a slurry electrode material in which an active material is dispersed in a liquid medium to a current collector, drying it, and then compacting it. As a method for manufacturing at low cost, a method using granulated particles obtained by granulating active material particles and a binder is known (see Patent Document 1).

As a method for producing a lithium ion battery in which a homogeneous active material layer can be obtained even with particles having low fluidity such as granulated particles obtained by granulating active material particles and a binder, for example, a current collector is transported. a supply unit for supplying granulated particles containing active material particles and a binder to the surface of the current collector being conveyed; a squeegee for leveling the supplied granulated particles; Granulation is performed by a device comprising an adjusting unit for controlling the height of the granulated particles stored on the upstream side of the squeegee and rolling rolls for rolling the flattened granulated particles to form an active material layer. A method of rolling particles is disclosed (see Patent Document 2).

JP 2014-078497 A JP 2016-119207 A

However, in the method described in Patent Document 2, the granulated particles are not stably supplied from the supply unit, and the surface of the active material is roughened, resulting in variations in the density of the active material layer, which leads to deterioration in electrical properties. This has been the cause of variations in production and a decrease in yield.

The present invention has been made in view of the above problems, and even when an electrode composition with low fluidity such as granulated particles is used, the electrode composition can be stably supplied and the surface roughness can be reduced. It is an object of the present invention to provide a supply device capable of obtaining an electrode active material layer free from ions and a method for manufacturing a lithium ion battery using the supply device.

The present inventors arrived at the present invention as a result of intensive studies in order to solve the above problems.
That is, the present invention provides a supply device for supplying an electrode composition containing an electrode active material and a non-aqueous electrolyte, comprising: a storage chamber for storing the electrode composition; A rotating belt portion for transporting the electrode composition, and a supply port for supplying the electrode composition to the outside, wherein the rotating belt portion is an annular transport belt that rotates in one direction along the surface thereof; and a first end and a second end forming a rotation axis of the annular transport belt, the annular transport belt on the first major surface is a direction from the first end toward the second end, and the second end of the rotating belt portion constitutes a part of the supply port. A supply device to be; a method for manufacturing a lithium ion battery electrode using the supply device of the present invention, wherein a sheet-like substrate is arranged below the supply port of the supply device, and the substrate is placed against the supply port An electrode composition supply step of supplying the electrode composition from the supply port onto the substrate while changing the position of the substrate in one direction, and on the substrate in the gap between the substrate and the supply device and an electrode active material layer forming step of adjusting the thickness of the electrode composition and obtaining an electrode active material layer made of the electrode composition by passing the electrode composition supplied to the A method for manufacturing an electrode for a lithium ion battery, characterized by:

The supply device of the present invention can stably supply the electrode composition even when the fluidity of the electrode composition is low.
The method for producing a lithium ion battery electrode of the present invention can obtain an electrode active material layer with no surface roughness even when the fluidity of the electrode composition is low.

FIG. 1 is a perspective view schematically showing an example of the feeding device of the present invention. FIG. 2 is a cross-sectional view taken along line AA in FIG. FIG. 3 is a cross-sectional view schematically showing another example of the supply device of the present invention. FIG. 4 is a cross-sectional view schematically showing still another example of the supply device of the present invention. FIG. 5 is a cross-sectional view schematically showing an example of the method for producing a lithium ion battery electrode of the present invention. FIG. 6 is a cross-sectional view schematically showing another example of the method for producing the lithium ion battery electrode of the present invention.

The present invention will be described in detail below.
In addition, in this specification, when describing a lithium ion battery, the concept includes a lithium ion secondary battery.

[Supply device]
A supply device of the present invention is a supply device for supplying an electrode composition containing an electrode active material and a non-aqueous electrolyte, comprising: a storage chamber for storing the electrode composition; It has a rotating belt portion for transporting the electrode composition and a supply port for supplying the electrode composition to the outside, and the rotating belt portion includes an annular transport belt that rotates in one direction along the surface thereof, and the supply The annular transport belt on the first major surface, having a first major surface in contact with the electrode composition inside the apparatus, and a first end and a second end forming the axis of rotation of the annular transport belt. is a direction from the first end toward the second end, and the second end of the rotating belt portion constitutes a part of the supply port. and

An example of the supply device of the present invention will be described with reference to FIGS. 1 and 2. FIG.
FIG. 1 is a perspective view schematically showing an example of the supply device of the present invention, and FIG. 2 is a cross-sectional view taken along line AA in FIG.
As shown in FIGS. 1 and 2, the supply device 1 includes a storage chamber 10 for storing an electrode composition containing an electrode active material and a non-aqueous electrolyte, and an electrode active material stored in the storage chamber 10. It has a rotating belt portion 20 for conveying and a supply port 30 for supplying the electrode composition to the outside.
As shown in FIG. 2 , the rotating belt portion 20 includes an annular conveying belt 21 that rotates in one direction along its surface, and a first main surface 20 a and a first main surface 20 a that come into contact with the electrode composition inside the supply device 1 . It has a second main surface 20b facing the surface 20a, and a first end portion 20c and a second end portion 20d that constitute the rotating shaft of the annular conveying belt 21. As shown in FIG.
The moving direction of the annular conveying belt 21 on the first main surface 20a is the direction from the first end 20c toward the second end 20d (the direction indicated by the arrow a in FIG. 2). 2 is a direction from the second end 20d toward the first end 20c (the direction indicated by the arrow b in FIG. 2).
The second end portion 20d of the rotating belt portion 20 constitutes one side of the supply port 30, and the opposite side thereof is formed of the lower end portion 40a of the wall material 40. As shown in FIG.
The supply port 30 has a substantially rectangular shape, the second end portion 20d of the rotating belt portion 20 forms one long side, and the lower end portion 40a of the wall member 40 forms the other long side.

In the supply device 1 , the annular conveying belt 21 extends toward the second end 20 d of the rotating belt portion 20 forming part of the supply port 30 on the first main surface 20 a arranged on the surface in contact with the electrode composition. The electrode active material stored in the storage chamber 10 is transported to the supply port 30 by the annular transport belt 21 .
Therefore, the supply device of the present invention can stably supply the electrode active material to the outside even when the fluidity of the electrode active material is low. In addition, by stably supplying the electrode active material onto the substrate using the supply device of the present invention, it is possible to suppress the density unevenness of the electrode active material and the surface roughness, thereby stabilizing the electrical characteristics and improving the product yield. can contribute to the improvement of

The shape and size of the storage chamber are not particularly limited as long as the storage chamber can store the electrode composition.
The inner wall of the storage chamber is preferably made of a material that does not adhere to the electrode composition.
As a material forming the inner wall, a material having a non-adhesive surface (hereinafter also referred to as a non-adhesive material) such as fluororesin can be used.
When the inner wall of the storage chamber is made of a non-adhesive material, the electrode composition can be stably discharged from the storage chamber.
Moreover, the inner wall of the storage chamber may be formed by coating the surface of a non-adhesive material such as metal with a non-adhesive material.

The moving speed of the circular conveying belt may be appropriately set according to the fluidity of the electrode composition, and is preferably 0.001 to 1 m/s, for example.

Although the material constituting the circular conveying belt is not particularly limited, non-adhesive materials such as fluororesins are preferred.
When the material constituting the circular conveying belt is a non-adhesive material, the electrode composition is less likely to adhere to the surface of the circular conveying belt, and variation in the supply amount of the electrode composition is suppressed.

Although the means for rotating the annular conveying belt is not particularly limited, for example, a method of rotating a rotating shaft using a rotating body such as a motor can be used.

In the supply device of the present invention, the shape of the supply port is not particularly limited, but a substantially rectangular shape is preferred. The substantially rectangular shape preferably has a short side length of 1 to 50 mm.
Moreover, it is preferable that one of the long sides of the substantially rectangular shape is formed by the second end portion of the rotating belt portion.

The position where the supply port is provided may be the bottom surface or the side surface of the supply device.

An example in which the supply port is provided on the side surface of the supply device will be described with reference to FIG.
FIG. 3 is a cross-sectional view schematically showing another example of the supply device of the present invention.
The supply device 2 shown in FIG. 3 has a storage chamber 10 , a rotating belt portion 20 and a supply port 30 .
The movement direction of the annular conveying belt 21 that constitutes the rotating belt portion 20 is the same as in FIG.
Therefore, even when the fluidity of the electrode active material is low, the electrode active material can be stably supplied to the outside.

In the feeding device of the present invention, the position where the rotating belt is disposed is not particularly limited as long as the second end of the rotating belt forms part of the supply port. For example, the rotating belt portion may be provided on the bottom surface inclined toward the supply port of the storage chamber, or may be provided on the side surface of the storage chamber.

An example in which the rotating belt portion is provided on the side surface of the storage chamber will be described with reference to FIG.
FIG. 4 is a cross-sectional view schematically showing still another example of the supply device of the present invention.
The supply device 3 shown in FIG. 4 has a storage chamber 10 , a rotating belt portion 20 and a supply port 30 . One side of the supply port 30 is formed by the second end portion 20 d of the rotating belt portion 20 , and the opposite side is formed by the lower end portion 41 a of the wall member 41 .
In the supply device 3, the annular conveying belt 21 constitutes one side of the supply port 30 on the first main surface 20a of the rotary belt portion 20, which is arranged on the surface facing the inside of the storage chamber 10 and in contact with the electrode composition. The electrode active material stored in the storage chamber 10 is transported to the supply port 30 by the annular transport belt 21 while moving toward the second end portion 20d of the rotating belt portion 20 (in the direction indicated by the arrow a). . Therefore, even when the fluidity of the electrode active material is low, the electrode active material can be stably supplied to the outside.
When the rotating belt portion is provided on the side surface of the storage chamber, the side surface of the storage chamber may be arranged perpendicular to the moving direction of the substrate, and the side surface of the storage chamber may be inclined from the vertical direction. may be placed.

[Method for producing electrode for lithium ion battery]
A method for producing a lithium ion battery electrode of the present invention is a method of producing a lithium ion battery electrode using the supply device of the present invention, wherein a sheet-like substrate is arranged below the supply port of the supply device. an electrode composition supplying step of supplying the electrode composition onto the substrate from the supply port while changing the position of the substrate with respect to the supply port in one direction; The thickness of the electrode composition is adjusted by allowing the electrode composition supplied on the base material to pass through the gap between the electrode active material layers to obtain the electrode active material layer composed of the electrode composition. and a forming step.

[Electrode composition supply step]
In the electrode composition supply step, a sheet-like substrate is placed below the supply port of the supply device of the present invention, and the electrode active material and the non-aqueous electrolyte are supplied while changing the position of the substrate with respect to the supply port in one direction. and is supplied onto the substrate from the supply port.
By using the supply device of the present invention, the electrode composition is stably supplied onto the substrate.

The material constituting the base material is not particularly limited, but a material that functions as a current collector such as a positive electrode current collector or a negative electrode current collector can be preferably used. When the base material functions as a current collector such as a positive electrode current collector or a negative electrode current collector, the manufacturing process of the electrode becomes simple, which is preferable.
Current collectors include metal current collector foils such as copper, aluminum, carbon-coated aluminum, titanium, stainless steel and nickel, and resin current collectors made of conductive polymers (described in JP-A-2012-150905, etc.). ), a conductive carbon sheet, a conductive glass sheet, and the like.
Resin films and fluororesins whose surfaces have been subjected to anti-adhesion treatment such as mold release treatment are preferable as materials that facilitate the separation of the electrode composition from the surface of the base material.
When the substrate does not function as a current collector such as a positive electrode current collector or a negative electrode current collector, it is preferable that the material facilitates separation of the electrode composition from the substrate surface. When a material that does not function as a current collector, such as a positive electrode current collector or a negative electrode current collector, is used as the base material, the electrode active material layer obtained after the electrode active material layer forming step described below is collected from the base material. An electrode can be manufactured by performing the process of transferring to an electric body.

[Electrode active material layer forming step]
In the electrode active material layer forming step, the electrode composition supplied onto the substrate in the electrode composition supplying step is passed through the gap between the substrate and the supply device of the present invention, thereby increasing the thickness of the electrode composition. By adjusting the thickness, an electrode active material layer made of the electrode composition is obtained.
Since the electrode composition supplied onto the substrate in the electrode composition supplying step has little density unevenness, the electrode active material layer forming step can provide an electrode active material layer with less surface roughness and less density unevenness.

In the electrode active material layer forming step, it is preferable to allow the electrode composition to pass through the gap between the substrate and the second end of the rotating belt.
When the electrode composition is to pass through the gap between the substrate and the second end of the rotating belt portion, the moving direction of the circular conveying belt at the position facing the substrate should be the same as the moving direction of the substrate. Just do it.
The electrode composition supplied onto the substrate by the circular transport belt passes through the gap between the substrate and the second end of the rotating belt portion, at the position of the circular transport belt facing the substrate. Since the direction of movement and the direction of movement of the substrate are the same, the shear stress applied to the electrode composition when passing through the gap between the substrate and the second end of the rotating belt portion is reduced, and the surface roughness is particularly reduced. can be suppressed.

Therefore, when the electrode composition is passed through the gap between the substrate and the second end of the rotating belt, the portion of the supply device that comes into contact with the electrode composition is the second end of the rotating belt. .
In the step of forming the electrode active material layer, the portion of the supplying device that comes into contact with the electrode composition includes the second end portion of the rotating belt portion described above, as well as the wall material that constitutes the supply port.

In the method for producing a lithium ion battery electrode of the present invention, the direction of movement of the circular conveying belt and the direction of movement of the substrate at the position facing the substrate may be the same direction or may be opposite directions. .
When the direction of movement of the circular conveying belt at the position facing the substrate and the direction of movement of the substrate are the same, in the step of forming the electrode active material layer, there is a gap between the substrate and the second end of the rotating belt portion. The electrode active material layer is passed through the gap. At this time, since the moving direction of the circular conveying belt and the moving direction of the base material are the same at the position facing the base material, the electrode active material layer passes through the gap between the base material and the supply device. The shearing force applied to the material layer is reduced, and roughening of the surface of the electrode active material layer can be particularly suppressed.

An example in which the moving direction of the circular conveying belt at the position facing the substrate is the same as the moving direction of the substrate will be described with reference to FIG.
FIG. 5 is a cross-sectional view schematically showing an example of the method for producing a lithium ion battery electrode of the present invention.
In FIG. 5, a sheet-like base material 100 is placed below the supply port 30 of the supply device 1, and the base material 100 is moved in one direction (the direction indicated by arrow A in FIG. 5) by rotating the rotor 110. Thereby, the position of the substrate 100 with respect to the supply port 30 is changed in one direction.
The electrode composition 50 is stored in the storage chamber 10 of the supply device 1, and on the first main surface 20a of the rotating belt portion 20, the annular conveying belt 21 moves from the first end portion 20c toward the second end portion 20d. The electrode composition 50 stored in the storage chamber 10 is conveyed toward the supply port 30 by moving the electrode composition 50 (in the direction indicated by the arrow a), and is supplied from the supply port 30 to the outside, that is, onto the substrate 100. , to become the electrode active material layer 51 .
One side of the supply port 30 is formed by the second end portion 20d of the rotating belt portion 20, and the opposite side is formed by the lower end portion 40a of the wall material 40 of the supply device 1. As shown in FIG.
The electrode active material layer 51 formed on the substrate 100 passes through the gap between the substrate 100 and the second end portion 20d of the rotating belt portion 20 as the substrate 100 moves in one direction. Thereby, the thickness of the electrode active material layer 51 is adjusted.
Since the moving direction of the annular conveying belt 21 at the position facing the substrate 100 is the same as the moving direction of the substrate 100, the shear stress applied to the surface of the electrode active material layer 51 is small. Therefore, roughening of the surface of the electrode active material layer 51 can be particularly suppressed.

An example in which the direction of movement of the circular conveying belt and the direction of movement of the substrate at the position facing the substrate are different will be described with reference to FIG.
FIG. 6 is a cross-sectional view schematically showing another example of the method for producing the lithium ion battery electrode of the present invention.
The method shown in FIG. 6 is similar to the method shown in FIG. 5, except that the orientation of the feeding device 1 is reversed.
In FIG. 6, the electrode active material layer 51 formed on the substrate 100 by the supply device 1 passes through the gap between the substrate 100 and the lower end portion 40a of the wall material 40 forming one side of the supply port 30. Thereby, the thickness of the electrode active material layer 51 is adjusted to a predetermined thickness.

In the method for producing a lithium ion battery electrode of the present invention, the method of changing the position of the base material in one direction with respect to the supply port is not particularly limited, and as shown in FIGS. You may move, and you may move a supply apparatus to one direction. Further, if the positions of the base material and the supply port change, the supply device may be moved in one direction while moving the base material in one direction. At this time, the moving direction of the substrate and the moving direction of the supply device may be the same or different.

As a method for moving the base material in one direction, for example, a belt conveyor can be used.
Examples of the method of moving the feeding device in one direction include a method of providing the feeding device with driving wheels and a method of winding a wire connected to the feeding device with a winch.

The length of the gap between the substrate and the supply device can be appropriately adjusted according to the thickness of the electrode active material layer to be obtained, and is preferably 0.03 to 2 mm, for example.

Further, in the electrode active material layer forming step, when the electrode active material layer is passed between the substrate and the second end of the rotating belt portion, the movement direction of the annular conveying belt at the position facing the substrate and the substrate is preferably the same as the moving direction of .

The angle formed by the first main surface of the rotating belt portion and the surface of the substrate is preferably more than 0° and 90° or less, more preferably 10° to 90°.

The electrode composition used in the electrode composition supply step contains an electrode active material and a non-aqueous electrolyte.

The electrode active material may be a positive electrode active material or a negative electrode active material.
Moreover, the electrode composition may contain a conductive aid, if necessary.

Examples of positive electrode active materials include composite oxides of lithium and transition metals (composite oxides containing one type of transition metal (LiCoO ₂ , LiNiO ₂ , LiAlMnO ₄ , LiMnO ₂ and LiMn ₂ O ₄ , etc.), transition metal elements Two kinds of composite oxides (for example, LiFeMnO ₄ , LiNi _1-x Co _x O ₂ , LiMn _1-y Co _y O ₂ , LiNi _1/3 Co _1/3 Al _1/3 O ₂ and LiNi _0.8 Co _0.15 Al _0.05 O ₂ ) and composite oxides containing three or more metal elements [for example, LiM _a M′ _b M″ _c O ₂ (M, M′ and M″ are different transition metal elements _{and satisfies a + b} + _c = _{1 .} ), transition metal oxides (eg MnO ₂ and V ₂ O ₅ ), transition metal sulfides (eg MoS ₂ and TiS ₂ ) and conductive polymers (eg polyaniline, polyvinylidene fluoride, polypyrrole, polythiophene, polyacetylene and poly- p-phenylene and polyvinylcarbazole) and the like, and two or more of them may be used in combination.
The lithium-containing transition metal phosphate may have a transition metal site partially substituted with another transition metal.

The volume average particle size of the positive electrode active material is preferably 0.01 to 100 μm, more preferably 0.1 to 35 μm, even more preferably 2 to 30 μm, from the viewpoint of the electrical characteristics of the battery. .

Examples of negative electrode active materials include carbon-based materials [graphite, non-graphitizable carbon, amorphous carbon, baked resin bodies (for example, carbonized products obtained by baking phenolic resin and furan resin, etc.), cokes (for example, pitch coke, needle coke and petroleum coke, etc.) and carbon fiber, etc.], silicon-based materials [silicon, silicon oxide (SiOx), silicon-carbon composites (carbon particles whose surface is coated with silicon and / or silicon carbide, silicon particles or oxide Silicon particles coated with carbon and/or silicon carbide, silicon carbide, etc.) and silicon alloys (silicon-aluminum alloy, silicon-lithium alloy, silicon-nickel alloy, silicon-iron alloy, silicon-titanium alloy, silicon - manganese alloys, silicon-copper alloys and silicon-tin alloys, etc.)], conductive polymers (e.g., polyacetylene and polypyrrole, etc.), metals (tin, aluminum, zirconium, titanium, etc.), metal oxides (titanium oxide and lithium-titanium oxides, etc.), metal alloys (eg, lithium-tin alloys, lithium-aluminum alloys, lithium-aluminum-manganese alloys, etc.), mixtures of these with carbonaceous materials, and the like.
Of the negative electrode active materials described above, those that do not contain lithium or lithium ions inside may be pre-doped in advance to include lithium or lithium ions in part or all of the negative electrode active material.

Among these, carbon-based materials, silicon-based materials, and mixtures thereof are preferable from the viewpoint of battery capacity and the like. As the carbon-based material, graphite, non-graphitizable carbon, and amorphous carbon are more preferable, and as the silicon-based material, , silicon oxide and silicon-carbon composites are more preferred.

The volume average particle size of the negative electrode active material is preferably 0.01 to 100 μm, more preferably 0.1 to 20 μm, even more preferably 2 to 10 μm, from the viewpoint of the electrical characteristics of the battery.

In the present specification, the volume average particle size of the negative electrode active material means the particle size (Dv50) at 50% integrated value in the particle size distribution determined by the microtrack method (laser diffraction/scattering method). The microtrack method is a method of obtaining a particle size distribution by utilizing scattered light obtained by irradiating particles with laser light. For the measurement of the volume average particle size, a Microtrac manufactured by Nikkiso Co., Ltd. or the like can be used.

The conductive aid is selected from materials having conductivity.
Specifically, metal [nickel, aluminum, stainless steel (SUS), silver, copper, titanium, etc.], carbon [graphite and carbon black (acetylene black, ketjen black, furnace black, channel black, thermal lamp black, etc.), etc. ], and mixtures thereof, but are not limited thereto.
One of these conductive aids may be used alone, or two or more thereof may be used in combination. Also, alloys or metal oxides thereof may be used. From the viewpoint of electrical stability, aluminum, stainless steel, carbon, silver, copper, titanium and mixtures thereof are preferred, silver, aluminum, stainless steel and carbon are more preferred, and carbon is even more preferred. These conductive aids may also be those obtained by coating a conductive material (a metal material among the materials of the conductive aids described above) around a particulate ceramic material or a resin material by plating or the like.

The average particle size of the conductive aid is not particularly limited, but from the viewpoint of the electrical characteristics of the battery, it is preferably 0.01 to 10 μm, more preferably 0.02 to 5 μm. It is more preferably 0.03 to 1 μm. In this specification, "particle size" means the maximum distance L among the distances between any two points on the contour line of the conductive aid. The value of "average particle size" is the average value of the particle size of particles observed in several to several tens of fields of view using an observation means such as a scanning electron microscope (SEM) or a transmission electron microscope (TEM). The calculated value shall be adopted.

The shape (form) of the conductive aid is not limited to a particle form, and may be in a form other than the particle form. good.

The conductive aid may be a conductive fiber having a fibrous shape.
Examples of conductive fibers include carbon fibers such as PAN-based carbon fibers and pitch-based carbon fibers, conductive fibers obtained by uniformly dispersing highly conductive metals and graphite in synthetic fibers, and metals such as stainless steel. Examples include fibrillated metal fibers, conductive fibers obtained by coating the surface of organic fibers with metal, and conductive fibers obtained by coating the surfaces of organic fibers with a resin containing a conductive substance. Among these conductive fibers, carbon fibers are preferred. A polypropylene resin in which graphene is kneaded is also preferable.
When the conductive aid is conductive fiber, the average fiber diameter is preferably 0.1 to 20 μm.

The electrode active material may be a coated active material in which at least part of the surface is coated with a coating layer containing a polymer compound.
When the periphery of the electrode active material is covered with the covering layer, the volume change of the electrode is moderated, and the expansion of the electrode can be suppressed.
The coated active material when the positive electrode active material is used as the electrode active material is called the coated positive electrode active material, and the coated active material layer is also called the coated positive electrode active material layer. Further, when the negative electrode active material is used as the electrode active material, the coated active material is called the coated negative electrode active material, and the coated negative electrode active material layer is also called the coated negative electrode active material layer.

As the polymer compound constituting the coating layer, those described as resins for non-aqueous secondary battery active material coating in JP-A-2017-054703 can be preferably used.

As the non-aqueous electrolyte, a known non-aqueous electrolyte containing an electrolyte and a non-aqueous solvent, which is used for manufacturing lithium ion batteries, can be used.

As _the electrolyte _, those used in known non _- aqueous _{electrolytes can} be used _{. 2} ) Lithium _salts of organic acids such as LiN( _{C2F5SO2 ) 2} , _LiC ( _{CF3SO2 ) 3} , and the like. Among these, LiPF ₆ is preferable from the viewpoint of battery output and charge-discharge cycle characteristics.

As the non-aqueous solvent, those used in known non-aqueous electrolytes can be used. , nitrile compounds, amide compounds, sulfones, sulfolane, etc. and mixtures thereof can be used.

Examples of lactone compounds include 5-membered ring (γ-butyrolactone, γ-valerolactone, etc.) and 6-membered ring lactone compounds (δ-valerolactone, etc.).

Cyclic carbonates include propylene carbonate, ethylene carbonate and butylene carbonate.
Chain carbonates include dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, methyl-n-propyl carbonate, ethyl-n-propyl carbonate and di-n-propyl carbonate.

Chain carboxylic acid esters include methyl acetate, ethyl acetate, propyl acetate and methyl propionate.
Cyclic ethers include tetrahydrofuran, tetrahydropyran, 1,3-dioxolane and 1,4-dioxane.
Chain ethers include dimethoxymethane and 1,2-dimethoxyethane.

Phosphate esters include trimethyl phosphate, triethyl phosphate, ethyldimethyl phosphate, diethylmethyl phosphate, tripropyl phosphate, tributyl phosphate, tri(trifluoromethyl) phosphate, tri(trichloromethyl) phosphate, Tri(trifluoroethyl) phosphate, tri(triperfluoroethyl) phosphate, 2-ethoxy-1,3,2-dioxaphospholan-2-one, 2-trifluoroethoxy-1,3,2- dioxaphospholan-2-one, 2-methoxyethoxy-1,3,2-dioxaphospholan-2-one and the like.
Acetonitrile etc. are mentioned as a nitrile compound. DMF etc. are mentioned as an amide compound. Sulfones include dimethylsulfone, diethylsulfone, and the like.
The non-aqueous solvent may be used singly or in combination of two or more.

Among non-aqueous solvents, lactone compounds, cyclic carbonates, chain carbonates and phosphates are preferred from the viewpoint of battery output and charge-discharge cycle characteristics, and lactone compounds, cyclic carbonates and chains are more preferred. Carbonic acid ester is particularly preferred is a mixture of cyclic carbonic acid ester and chain carbonic acid ester. Most preferred is a mixture of ethylene carbonate and dimethyl carbonate or a mixture of ethylene carbonate and diethyl carbonate.

A method for producing the above-described coated active material will be described.
The coated active material may be produced, for example, by mixing a polymer compound, an electrode active material, and an optional conductive agent. When a conductive agent is used in the coating layer, the polymer compound and conductive agent are mixed. After preparing the coating material, the coating material may be mixed with the electrode active material, or the polymer compound, the conductive agent and the electrode active material may be mixed.
When the electrode active material, the polymer compound, and the conductive agent are mixed, the mixing order is not particularly limited, but after mixing the electrode active material and the polymer compound, the conductive agent is further added and further mixed. is preferred.
By the above method, at least part of the surface of the electrode active material is coated with a coating layer containing a polymer compound and optionally a conductive agent.

As the conductive agent, which is an optional component of the coating material, the same conductive aids that constitute the electrode composition can be suitably used.

The electrode composition may further contain known solvent-drying binders for electrodes (carboxymethylcellulose, SBR latex, polyvinylidene fluoride, etc.), adhesive resins, and the like.
However, it is desirable to contain an adhesive resin instead of a known electrode binder. When the electrode composition contains the known solution-drying type electrode binder, it is necessary to integrate the electrode composition by performing a drying step after the electrode active material layer forming step. When containing, the electrode composition can be integrated with a slight pressure at normal temperature without performing a drying process. If the drying step is not performed, the electrode composition will not shrink or crack due to heating, which is preferable.
Further, in the electrode composition containing the electrode active material, the non-aqueous electrolyte and the adhesive resin, the electrode active material layer is maintained as a non-bonded body even after the electrode active material layer forming step. . If the electrode active material layer is a non-binder, the thickness of the electrode active material layer can be increased, and a high-capacity battery can be obtained, which is preferable.
As the adhesive resin, a polymer compound constituting the coating layer (such as a non-aqueous secondary battery active material coating resin described in JP-A-2017-054703) is mixed with a small amount of an organic solvent to obtain a glass transition. Those whose temperature is adjusted to room temperature or lower, and those described as adhesives in JP-A-10-255805 and the like can be preferably used.
Here, the non-bonded body means that the electrode active materials constituting the electrode composition are not bonded to each other, and the bonded body means that the electrode active materials are irreversibly fixed to each other. do.
The solution-drying type electrode binder is one that evaporates the solvent component to dry and solidify, thereby firmly adhering and fixing the active materials to each other. On the other hand, the tacky resin means a resin having tackiness (property of adhering by applying slight pressure without using water, solvent, heat, etc.).
The solution-drying type electrode binder and the adhesive resin are different materials.

In the method for producing a lithium ion battery electrode of the present invention, the electrode composition is a wet powder containing an electrode active material and a non-aqueous electrolyte.
More preferably, the wet powder is in a pendular or funicular state.

The ratio of the non-aqueous electrolyte in the wet powder is not particularly limited, but in the case of the positive electrode, the ratio of the non-aqueous electrolyte to the entire wet powder is 0.5 to 0.5 to make the pendular state or funicular state. 15% by weight, and in the case of the negative electrode, the ratio of the non-aqueous electrolyte is preferably 0.5 to 25% by weight of the entire wet powder.

The supply device of the present invention can stably supply not only a conventional electrode composition with good fluidity but also an electrode composition with low fluidity.

The supply device of the present invention is particularly useful as a manufacturing device for manufacturing electrodes for bipolar secondary batteries and lithium ion secondary batteries used for mobile phones, personal computers, hybrid vehicles and electric vehicles.
In addition, the method for producing a lithium ion battery electrode of the present invention particularly produces electrodes for bipolar secondary batteries and lithium ion secondary batteries used for mobile phones, personal computers, hybrid automobiles and electric automobiles. It is useful as a method.

1, 2, 3 supply device 10 storage chamber 20 rotating belt portion 20a first main surface 20b second main surface 20c first end portion 20d second end portion 21 annular conveying belt 30 supply port 40, 41, 42 wall material 40a, 41a Lower end portion 50 of wall material Electrode composition 51 Electrode active material layer 100 Base material 110 Rotating body

Claims (3)

A supply device for supplying an electrode composition comprising an electrode active material and a non-aqueous electrolyte,
A storage chamber for storing the electrode composition, a rotating belt portion for conveying the electrode composition stored in the storage chamber, and a supply port for supplying the electrode composition to the outside,
The rotating belt portion constitutes a circular conveying belt that rotates in one direction along its surface, a first main surface that contacts the electrode composition inside the supply device, and a rotating shaft of the circular conveying belt. having a first end and a second end;
a moving direction of the annular conveying belt on the first main surface is a direction from the first end toward the second end;
The supply device, wherein the second end of the rotating belt part constitutes a part of the supply port. A method for manufacturing a lithium ion battery electrode using the supply device according to claim 1 ,
A sheet-like substrate is placed below the supply port of the supply device, and the electrode composition is supplied onto the substrate from the supply port while changing the position of the substrate with respect to the supply port in one direction. an electrode composition supplying step;
By passing the electrode composition supplied onto the substrate through a gap between the substrate and the supply device, the thickness of the electrode composition is adjusted, and an electrode made of the electrode composition and an electrode active material layer forming step of obtaining an active material layer. 3. The electrode composition according to claim 2 , wherein in the electrode active material layer forming step, the electrode composition supplied onto the substrate is allowed to pass through a gap between the substrate and the second end of the rotating belt portion. A method for producing an electrode for a lithium ion battery.

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