Patent Description:
Hitherto, a slurry manufacturing apparatus for producing a slurry by mixing a powder and a solvent has been known. For example, PTL <NUM> discloses a slurry manufacturing apparatus for producing a slurry for a positive electrode of a non-aqueous electrolyte secondary battery by mixing a powder (an active material that occludes and releases alkali metal ions, a carbon-based conductivity aid, and an aqueous binder) and a solvent (water). PTL <NUM> discloses an apparatus for treating slurries containing minerals, soils and sludges which have been contaminated with toxic organic compounds making them hazardous waste under environmental laws and regulations. PTL <NUM> discloses a novel process and apparatus for transferring gas in liquid which combine various advantages of the existing methods but eliminate certain disadvantages. PTL <NUM> discloses a process and a device for mixing fluid into a pulp suspension of cellulose-containing fibre material.

In lithium composite oxides contained in the slurry for the positive electrode, lithium hydroxide added during the synthesis remains. Lithium hydroxide comes into contact with water and increases the pH value of the slurry. There is concern that the slurry that is strongly alkaline and has a pH value of more than <NUM> may corrode an aluminum current collector during coating.

In the slurry manufacturing apparatus disclosed in PTL <NUM>, carbon dioxide gas is supplied into the apparatus, and the carbon dioxide gas is dissolved in the slurry for the positive electrode produced in the apparatus. Accordingly, an alkaline component in the slurry is neutralized. As the alkaline component in the slurry is neutralized, corrosion of the aluminum current collector is prevented.

The slurry manufacturing apparatus disclosed in <CIT> emits a surplus of carbon dioxide gas supplied into the apparatus from an air emission pipe to the outside. However, there is concern that the emission of carbon dioxide gas may increase the environmental load on the surrounding environment.

In addition, of the carbon dioxide gas supplied into the apparatus, the carbon dioxide gas emitted to the outside does not contribute to the neutralization of the alkaline component in the slurry. Therefore, it is required to reduce the amount of carbon dioxide gas that does not contribute to the neutralization of the alkaline component in the slurry and reduce the amount of carbon dioxide gas supplied into the apparatus.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a slurry manufacturing apparatus capable of reducing the amount of reaction gas emitted from the apparatus and reducing the amount of reaction gas supplied into the apparatus. Solution to Problem.

A slurry manufacturing apparatus according to the present invention is specified in claim <NUM>. A corresponding method is specified in claim <NUM>.

According to the said configuration, the surplus of the reaction gas supplied to the mixing chamber by the supply unit is recovered by the circulation unit and resupplied to the mixing chamber. Accordingly, at least a portion of the reaction gas to be supplied to the mixing chamber by the supply unit can be replaced by the reaction gas resupplied from the circulation unit. As a result, the amount of the reaction gas supplied to the mixing chamber by the supply unit can be reduced. Accordingly, the amount of the reaction gas emitted to the outside can be reduced, so that the environmental load can be reduced.

According to the present invention, the amount of the reaction gas emitted from the apparatus can be reduced, and the amount of the reaction gas supplied into the apparatus can be reduced.

Hereinafter, a slurry manufacturing apparatus <NUM> according to a first embodiment of the present invention will be described. Embodiments described below are merely an example of the present invention, and it is needless to say that the embodiments of the present invention can be appropriately changed without changing the concept of the present invention.

A slurry manufacturing apparatus <NUM> illustrated in <FIG> and <FIG> includes a dispersion mixing pump <NUM>, a powder supply unit <NUM>, a solvent supply unit <NUM>, a gas supply unit <NUM>, and a circulation unit <NUM>. In <FIG>, the powder supply unit <NUM> is omitted. The dispersion mixing pump <NUM> is an example of a mixing unit. The gas supply unit <NUM> is an example of a supply unit.

As illustrated in <FIG>, the dispersion mixing pump <NUM> has a mixing chamber <NUM>. The dispersion mixing pump <NUM> illustrated in <FIG> and <FIG> mixes a powder P and a solvent R in the mixing chamber <NUM> and produces a slurry F with a reaction gas G supplied. The powder supply unit <NUM> illustrated in <FIG> supplies the powder P to the mixing chamber <NUM>. The solvent supply unit <NUM> illustrated in <FIG> and <FIG> supplies the solvent R to the mixing chamber <NUM>. The gas supply unit <NUM> illustrated in <FIG> and <FIG> supplies the reaction gas G to the mixing chamber <NUM>. The circulation unit <NUM> illustrated in <FIG> and <FIG> recovers the reaction gas G from the mixing chamber <NUM> and resupplies the recovered reaction gas G to the mixing chamber <NUM>.

The slurry manufacturing apparatus <NUM> in the present embodiment is an apparatus for manufacturing a slurry for a positive electrode of a non-aqueous electrolyte secondary battery using an aqueous solvent containing an alkali metal composite oxide. The powder P is a slurry material used for manufacturing an electrode for the non-aqueous electrolyte secondary battery, and is an active material that occludes and releases alkali metal ions, a carbon-based conductivity aid, and an aqueous binder. The solvent R is water, and the reaction gas G is carbon dioxide gas.

As illustrated in <FIG>, the powder supply unit <NUM> includes a hopper <NUM>, a powder supply pipe <NUM>, and a valve <NUM>.

The hopper <NUM> is formed in an inverted conical shape which is decreased in diameter from the upper portion toward the lower portion, and is disposed in a posture with a center axis along a vertical direction. The hopper <NUM> discharges the powder P received from an upper opening portion <NUM> from a lower opening portion <NUM>. The lower opening portion <NUM> of the hopper <NUM> is connected to the powder supply pipe <NUM>.

The powder supply pipe <NUM> is a cylindrical pipe disposed in a state with a center axis inclined with respect to the vertical direction. The upper portion of the powder supply pipe <NUM> is connected to the lower opening portion <NUM> of the hopper <NUM>. The lower portion of the powder supply pipe <NUM> is connected to the dispersion mixing pump <NUM> (specifically, a first supply unit <NUM> of the dispersion mixing pump <NUM>). A position where the powder supply pipe <NUM> and the first supply unit <NUM> are connected is a connection position P1.

As illustrated in <FIG> and <FIG>, the valve <NUM> opens and closes the powder supply pipe <NUM> by a shutter <NUM> (see <FIG>) moved by an air cylinder <NUM> (see <FIG>). Means for moving the shutter <NUM> does not have to be the air cylinder <NUM> and may be, for example, a hydraulic cylinder or a motor. In a state where the valve <NUM> is opened, the hopper <NUM> and the first supply unit <NUM> communicate with each other via the powder supply pipe <NUM>. That is, the powder P can move from the hopper <NUM> to the first supply unit <NUM> through the powder supply pipe <NUM>. In a state where the valve <NUM> is closed, the communication between the hopper <NUM> and the first supply unit <NUM> is blocked by the shutter <NUM>. At this time, the powder P cannot move from the hopper <NUM> to the first supply unit <NUM>.

As illustrated in <FIG>, the solvent supply unit <NUM> includes a storage tank (an example of a storage unit) <NUM> and a slurry resupply pipe <NUM>.

The solvent R and the slurry F are stored in the storage tank <NUM>. The solvent R is supplied to the storage tank <NUM> via a solvent supply port <NUM>. The slurry F is recovered from the dispersion mixing pump <NUM> via a recovery pipe <NUM> of the circulation unit <NUM> and a recovery port <NUM>.

The storage tank <NUM> includes a gas port <NUM> and a stirring mechanism <NUM>. The gas port <NUM> is connected to an intake pipe <NUM> of the circulation unit <NUM>. The reaction gas G inside the storage tank <NUM> can move to the intake pipe <NUM> via the gas port <NUM>. The stirring mechanism <NUM> is disposed inside the storage tank <NUM>. The stirring mechanism <NUM> is driven by a motor <NUM> to stir the solvent R and the slurry F inside the storage tank <NUM>.

The slurry resupply pipe <NUM> connects the storage tank <NUM>, the powder supply pipe <NUM>, and the first supply unit <NUM>. One end of the slurry resupply pipe <NUM> is connected to the storage tank <NUM>. The other end of the slurry resupply pipe <NUM> is connected to the powder supply pipe <NUM> and the first supply unit <NUM> at the connection position P1.

The slurry resupply pipe <NUM> is provided with a pump <NUM> and a flow rate sensor <NUM>. The pump <NUM> suctions the solvent R and the slurry F stored in the storage tank <NUM> and delivers the solvent R and the slurry F toward the other end of the slurry resupply pipe <NUM>, that is, toward the first supply unit <NUM>. The flow rate sensor <NUM> outputs a signal corresponding to the flow rates of the solvent R and the slurry F flowing through the slurry resupply pipe <NUM> to a control unit (not illustrated).

The control unit controls operations of the slurry manufacturing apparatus <NUM>. The control unit may be realized by a central processing unit (CPU) that executes a program stored in the memory, may be realized by a hardware circuit, or may be a combination thereof.

As illustrated in <FIG> and <FIG>, the gas supply unit <NUM> includes a cylinder <NUM>, a gas supply pipe <NUM>, and a valve <NUM>.

The cylinder <NUM> stores the reaction gas G.

As illustrated in <FIG>, the gas supply pipe <NUM> is a cylindrical pipe. One end of the gas supply pipe <NUM> is connected to the upper end portion of the cylinder <NUM>. As illustrated in <FIG>, the other end of the gas supply pipe <NUM> is connected to the slurry resupply pipe <NUM> at a connection position P2. The connection position P2 is a position between the flow rate sensor <NUM> and the connection position P1 in the slurry resupply pipe <NUM>.

The valve <NUM> illustrated in <FIG> and <FIG> opens and closes the gas supply pipe <NUM>. In a state where the valve <NUM> is opened, the cylinder <NUM> and the dispersion mixing pump <NUM> communicate with each other via the gas supply pipe <NUM>, the connection position P2, the slurry resupply pipe <NUM>, the connection position P1, and the powder supply pipe <NUM>. At this time, the reaction gas G can move to the first supply unit <NUM> through the gas supply pipe <NUM> and the slurry resupply pipe <NUM> between the connection position P2 and the connection position P1. In a state where the valve <NUM> is closed, the communication between the cylinder <NUM> and the first supply unit <NUM> is blocked by the valve <NUM>. At this time, the reaction gas G cannot move from the cylinder <NUM> to the first supply unit <NUM>.

As illustrated in <FIG> and <FIG>, the dispersion mixing pump <NUM> includes a casing <NUM>, the first supply unit <NUM>, a discharge unit <NUM>, a second supply unit <NUM>, a mixing rotor <NUM>, a pump drive motor <NUM>, a partition plate <NUM>, and a stator <NUM>, a pressure sensor <NUM>, and a discharge pipe <NUM>.

As illustrated in <FIG>, the casing <NUM> includes a cylindrical outer peripheral wall portion <NUM> having openings at both ends closed by a front wall portion <NUM> and a rear wall portion <NUM>. The casing <NUM> has the mixing chamber <NUM> therein, which is divided by the front wall portion <NUM>, the rear wall portion <NUM>, and the outer peripheral wall portion <NUM>. The mixing chamber <NUM> is divided into a blade chamber <NUM> and an introduction chamber by the stator <NUM>. The introduction chamber is divided into a first introduction chamber <NUM> and a second introduction chamber <NUM> by the partition plate <NUM>. That is, the mixing chamber <NUM> is constituted of the blade chamber <NUM>, the first introduction chamber <NUM>, and the second introduction chamber <NUM>.

The first supply unit <NUM> is provided at a position shifted to the outer peripheral side of the center axis (axial center A3 of the casing <NUM>) of the front wall portion <NUM>. In the present embodiment, the downward inclination angle of the first supply unit <NUM> with respect to a horizontal direction (left-right direction in <FIG>) is about <NUM> degrees. The first supply unit <NUM> has a substantially cylindrical shape.

One end of the first supply unit <NUM> communicates with the first introduction chamber <NUM>. As illustrated in <FIG>, the other end of the first supply unit <NUM> communicates with the connection position P1. As illustrated in <FIG>, one end portion of the first supply unit <NUM> (an opening portion of the first supply unit <NUM> that opens into the casing <NUM>) has a part of an annular groove <NUM> formed in the front wall portion <NUM> therein. The powder P supplied by the powder supply unit <NUM>, the solvent R supplied by the solvent supply unit <NUM>, and the reaction gas G supplied by the gas supply unit <NUM> are introduced to the first introduction chamber <NUM> via the first supply unit <NUM>.

The discharge unit <NUM> discharges the slurry F produced by mixing the powder P and the solvent R in the mixing chamber <NUM>. The discharge unit <NUM> has a substantially cylindrical shape. The discharge unit <NUM> is provided at one location in the circumferential direction of the outer peripheral wall portion <NUM> and communicates with the blade chamber <NUM>.

As illustrated in <FIG>, the discharge unit <NUM> extends in the tangential direction of the outer peripheral wall portion <NUM>. In other words, the discharge unit <NUM> and a discharge pipe <NUM> extend from the mixing chamber <NUM> in a direction perpendicular to the axial center A3. Accordingly, the rotation of the mixing rotor <NUM> can generate a gas flow from the mixing chamber <NUM> toward the discharge unit <NUM> and the discharge pipe <NUM>. Along this flow, the reaction gas G in the mixing chamber <NUM> can be easily sent to the discharge unit <NUM> and the discharge pipe <NUM>.

The discharge unit <NUM> and the discharge pipe <NUM> do not necessarily have to be perpendicular to the axial center A3. As long as the discharge unit <NUM> and the discharge pipe <NUM> extend in a direction in which the gas is introduced into the discharge unit <NUM> and the discharge pipe <NUM> along the gas flow formed by the rotation of the mixing rotor <NUM>, an effect of easily sending the reaction gas G in the mixing chamber <NUM> can be obtained. That is, the rotation direction of the mixing rotor <NUM> in the vicinity of the discharge unit <NUM> and the discharge pipe <NUM> and the extension direction of the discharge unit <NUM> and the discharge pipe <NUM> may be substantially the same direction.

In addition, the discharge unit <NUM> extends from the upper portion side of the mixing chamber <NUM>. The upper portion side of the mixing chamber <NUM> is, in the mixing chamber <NUM>, a position above a height <NUM> which is the midpoint between an upper end <NUM> and a lower end <NUM> of the mixing chamber <NUM>, that is, above the height <NUM> the same as the axial center A3. In the mixing chamber <NUM>, the reaction gas G, which is a gas, tends to be located above the slurry F, which is a solid or a liquid. Therefore, with the discharge unit <NUM> extending from the upper portion side of the mixing chamber <NUM>, the reaction gas G can be easily sent to the discharge pipe <NUM>.

As illustrated in <FIG>, the second supply unit <NUM> protrudes from the center portion of the front wall portion <NUM>. One end of the second supply unit <NUM> is connected to the front wall portion <NUM> and communicates with the second introduction chamber <NUM>. As illustrated in <FIG>, the other end of the second supply unit <NUM> is connected to a circulation flow path <NUM> of a recirculation mechanism unit <NUM>. The second supply unit <NUM> has a cylindrical shape. As illustrated in <FIG>, the axial center of the second supply unit <NUM> coincides with the axial center A3 of the casing <NUM>. A throttle portion <NUM> is formed in the second supply unit <NUM>. The inner diameter of the throttle portion <NUM> is smaller than the inner diameter of the circulation flow path <NUM>, and is smaller than the inner diameter of a tubular sliding contact portion <NUM> of the partition plate <NUM>. That is, the flow path area of the throttle portion <NUM> is smaller than the flow path area of the circulation flow path <NUM>, and is smaller than the flow path area of the tubular sliding contact portion <NUM>.

As illustrated in <FIG> and <FIG>, the mixing rotor <NUM> is rotatably provided inside the casing <NUM>. The axial center of the mixing rotor <NUM> coincides with the axial center A3 of the casing <NUM>.

The mixing rotor <NUM> is configured to have a shape in which the front surface bulges substantially into a truncated cone shape. A plurality of rotor blades <NUM> are attached to the outer peripheral side of the mixing rotor <NUM>. The plurality of rotor blades <NUM> are arranged at equal intervals in a state of protruding forward from the mixing rotor <NUM>. In <FIG>, ten rotor blades <NUM> are arranged at equal intervals in the circumferential direction. The rotor blade <NUM> protrudes from the outer peripheral side toward the inner peripheral side of the mixing rotor <NUM> so as to be inclined rearward in the rotation direction from the inner peripheral side toward the outer peripheral side.

As illustrated in <FIG>, the mixing rotor <NUM> is connected to a drive shaft <NUM> of the pump drive motor <NUM> inserted into the casing <NUM> through the rear wall portion <NUM>. The mixing rotor <NUM> is driven by the pump drive motor <NUM> to rotate.

Since the rotor blade <NUM> has the above-described configuration, when the mixing rotor <NUM> is driven to rotate in a direction in which the tip part of the rotor blade <NUM> faces forward when viewed in the axial center direction (rotation direction indicated by arrows in <FIG>), cavitation (local boiling) occurs according to the pressure difference between the inside and the outside of the mixing chamber <NUM> in the slurry F located in a space behind a rear surface <NUM>, which is the surface on the rear side in the rotation direction of the rotor blade <NUM>.

As illustrated in <FIG> and <FIG>, the partition plate <NUM> is disposed between the front wall portion <NUM> and the mixing rotor <NUM> in the mixing chamber <NUM>. As illustrated in <FIG>, the partition plate <NUM> divides the introduction chamber, which is the space on the inner peripheral side of the stator <NUM> in the mixing chamber <NUM>, into the first introduction chamber <NUM> on the front wall portion <NUM> side and the second introduction chamber <NUM> on the mixing rotor <NUM> side.

As illustrated in <FIG> and <FIG>, the partition plate <NUM> is configured in a substantially funnel shape having an outer diameter slightly smaller than the inner diameter of the stator <NUM>. The partition plate <NUM> is provided with a funnel-shaped portion <NUM> protruding in a cylindrical shape at the center portion thereof. The tubular sliding contact portion <NUM> at the top of the funnel-shaped portion <NUM> is open. In addition, the partition plate <NUM> is provided with an annular flat plate portion <NUM> at the outer peripheral portion of the funnel-shaped portion <NUM> with both the front surface and the rear surface being in a state perpendicular to the axial center A3 of the casing <NUM>.

The partition plate <NUM> is attached to attachment portions <NUM> of the front surface of the mixing rotor <NUM> via spacing members <NUM> in a posture in which the tubular sliding contact portion <NUM> faces the front wall portion <NUM> side. As illustrated in <FIG>, the spacing members <NUM> are arranged at a plurality of (in this embodiment, four) locations at equal intervals in the circumferential direction. Stirring blades <NUM> are attached to the spacing members <NUM>.

As illustrated in <FIG> and <FIG>, scraping blades <NUM> are provided on the surface of the partition plate <NUM> on the front wall portion <NUM> side. As illustrated in <FIG>, a plurality of (in <FIG>, four) scraping blades <NUM> are concentrically provided at equal intervals in the circumferential direction. As illustrated in <FIG>, the scraping blades <NUM> are located in the first introduction chamber <NUM>. The tip part of the scraping blade <NUM> is fitted into the annular groove <NUM>.

As illustrated in <FIG>, the scraping blade <NUM> is formed in a rod shape. A base end part <NUM> of the scraping blade <NUM> is fixed to rotate integrally with the mixing rotor <NUM> in an inclined posture in which the scraping blade <NUM> is located closer to the front wall portion <NUM> toward the tip end side of the scraping blade <NUM> when viewed in a radial direction of the mixing rotor <NUM> (viewed in a direction into the paper of <FIG>) and is located closer to the radially inner side of the mixing rotor <NUM> toward the tip end side of the scraping blade <NUM> when viewed in the axial center direction of the mixing rotor <NUM> (viewed in a direction into the paper of <FIG>).

When the mixing rotor <NUM> rotates, the partition plate <NUM> rotates integrally with the mixing rotor <NUM>. At this time, each of the scraping blades <NUM> revolves integrally with the mixing rotor <NUM> in a state where a tip part <NUM> thereof enters the annular groove <NUM> (see <FIG>).

As illustrated in <FIG> and <FIG>, the stator <NUM> is a cylindrical member. As illustrated in <FIG>, the stator <NUM> is disposed in the mixing chamber <NUM>. Specifically, the stator <NUM> is disposed between the front wall portion <NUM> and the mixing rotor <NUM> as illustrated in <FIG>, and is disposed to surround the mixing rotor <NUM> when viewed in the horizontal direction along the axial center A3 as illustrated in <FIG>. As illustrated in <FIG>, the stator <NUM> is attached to the inner surface of the front wall portion <NUM> (the surface facing the mixing rotor <NUM>). As illustrated in <FIG>, the partition plate <NUM> divides the mixing chamber <NUM> into the blade chamber <NUM> on the outer peripheral wall portion <NUM> side and the introduction chamber (the first introduction chamber <NUM> and the second introduction chamber <NUM>) on the mixing rotor side.

As illustrated in <FIG>, the blade chamber <NUM> is annular. The plurality of rotor blades <NUM> protruding from the mixing rotor <NUM> are located in the blade chamber <NUM>.

As illustrated in <FIG> and <FIG>, a plurality of through-holes <NUM> and <NUM> are formed in the stator <NUM>. A plurality of the through-holes <NUM> are arranged at equal intervals in the circumferential direction at a portion of the stator <NUM> facing the first introduction chamber <NUM>. A plurality of the through-holes <NUM> are arranged at equal intervals in the circumferential direction at a portion of the stator <NUM> facing the second introduction chamber <NUM>. Therefore, as illustrated in <FIG>, the blade chamber <NUM> communicates with the first introduction chamber <NUM> through the through-holes <NUM> and communicates with the second introduction chamber <NUM> through the through-holes <NUM>.

As illustrated in <FIG> and <FIG>, the pressure sensor <NUM> is attached to the front wall portion <NUM>. The pressure sensor <NUM> outputs a signal corresponding to the pressure inside the first introduction chamber <NUM> to the control unit.

As illustrated in <FIG>, the discharge pipe <NUM> is connected to the lower portion of the mixing chamber <NUM> via a valve <NUM>. The discharge pipe <NUM> is connected to a slurry outlet. The valve <NUM> is opened when the produced slurry F is taken out. The position where the discharge pipe <NUM> is connected is not limited to the mixing chamber <NUM>, and for example, the discharge pipe <NUM> may be connected to the slurry resupply pipe <NUM>.

The recirculation mechanism unit <NUM> illustrated in <FIG> separates the dissolved liquid in a cylindrical container <NUM> by specific gravity. Specifically, the recirculation mechanism unit <NUM> may separate, in the slurry F supplied from the discharge unit <NUM> of the dispersion mixing pump <NUM> via the discharge pipe <NUM>, an undispersed slurry Fr in a state in which the powder P that is not completely dispersed and mixed may be contained from the slurry F in a state in which the powder P is almost completely dispersed and mixed. The undispersed slurry Fr is sent to the circulation flow path <NUM>. The slurry F is sent to the recovery pipe <NUM> of the circulation unit <NUM> together with bubbles contained in the slurry F. The discharge pipe <NUM> and the circulation flow path <NUM> are each connected to the lower portion of the cylindrical container <NUM>. The recovery pipe <NUM> is connected to the upper portion of the cylindrical container <NUM>.

As illustrated in <FIG> and <FIG>, the circulation unit <NUM> includes the recovery pipe <NUM>, the intake pipe <NUM>, a pump <NUM>, a gas resupply pipe <NUM>, a temperature sensor <NUM>, a valve <NUM>, the discharge pipe <NUM>, and the cylindrical container <NUM>. Here, in the following description, the discharge pipe <NUM> and the recovery pipe <NUM> for recovering the slurry F and a surplus of the reaction gas from the mixing chamber <NUM> to the storage tank <NUM> are collectively referred to as a first pipe. In addition, the intake pipe <NUM> and the gas resupply pipe <NUM> for resupplying the surplus of the reaction gas from the storage tank <NUM> to the mixing chamber <NUM> are collectively referred to as a second pipe. Furthermore, in the second pipe, the intake pipe <NUM> is also referred to as a first part, and the gas resupply pipe <NUM> is also referred to as a second part.

The recovery pipe <NUM> connects the cylindrical container <NUM> to the storage tank <NUM>. One end of the recovery pipe <NUM> is connected to the upper portion of the cylindrical container <NUM>. The other end of the recovery pipe <NUM> is connected to the recovery port <NUM> of the storage tank <NUM>.

The temperature sensor <NUM> is disposed in the recovery pipe <NUM>. The temperature sensor TI outputs a signal corresponding to the temperature of the slurry F flowing through the inside of the recovery pipe <NUM> to the control unit.

The intake pipe <NUM> connects the storage tank <NUM> to the pump <NUM>. One end of the intake pipe <NUM> is connected to the gas port <NUM> of the storage tank <NUM>. The other end of the intake pipe <NUM> is connected to a suction port <NUM> of the pump <NUM>.

The pump <NUM> suctions the reaction gas G from the mixing chamber <NUM> via the discharge unit <NUM>, the discharge pipe <NUM>, the cylindrical container <NUM>, the recovery pipe <NUM>, the storage tank <NUM>, and the intake pipe <NUM>.

In addition, the pump <NUM> sends the suctioned reaction gas G to the mixing chamber <NUM> via the gas resupply pipe <NUM>, (specifically, via the gas resupply pipe <NUM>, the gas supply pipe <NUM> between a connection position P3 and the connection position P2, the slurry resupply pipe <NUM> between the connection position P2 and the connection position P1, and the first supply unit <NUM>). The connection position P3 is a position in the gas supply pipe <NUM> between the valve <NUM> and the connection position P2.

In the present embodiment, the pump <NUM> is a vacuum pump. Since the configuration of the vacuum pump is known, detailed descriptions thereof will be omitted here. A vacuum pump has a strong force of pulling a gas and is thus suitable as a pump used in the present embodiment. The pump <NUM> is not limited to the vacuum pump, and for example, other known pumps such as a diaphragm pump may be adopted.

The pump <NUM> includes the suction port <NUM> and a discharge port <NUM>. The intake pipe <NUM> is connected to the suction port <NUM> as described above. The gas resupply pipe <NUM> is connected to the discharge port <NUM>.

The gas resupply pipe <NUM> connects the pump <NUM> to the gas supply pipe <NUM>. One end of the gas resupply pipe <NUM> is connected to the discharge port <NUM> of the pump <NUM> as described above. The other end of the gas resupply pipe <NUM> is connected to the gas supply pipe <NUM> at the connection position P3.

The valve <NUM> is disposed in the gas resupply pipe <NUM>. The valve <NUM> is an example of a pipeline on-off valve. The valve <NUM> opens and closes the gas resupply pipe <NUM>. In a state where the valve <NUM> is open, the pump <NUM> and the mixing chamber <NUM> communicate with each other via the gas resupply pipe <NUM>, the gas supply pipe <NUM> between the connection position P3 and the connection position P2, the slurry resupply pipe <NUM> between the connection position P2 and the connection position P1, and the first supply unit <NUM>. At this time, the reaction gas G suctioned by the pump <NUM> can move to the mixing chamber <NUM>. In a state where the valve <NUM> is closed, the communication between the pump <NUM> and the mixing chamber <NUM> is blocked by the valve <NUM>. At this time, the reaction gas G suctioned by the pump <NUM> cannot move to the mixing chamber <NUM>.

In the present embodiment, the valve <NUM> is provided in the gas resupply pipe <NUM>, but the valve <NUM> may be provided in at least one of the intake pipe <NUM> and the gas resupply pipe <NUM>. The valve <NUM> may not be provided.

Hereinafter, a method for manufacturing a slurry by the slurry manufacturing apparatus <NUM> will be described with reference to <FIG> and <FIG>. In addition, other figures are referenced as appropriate.

In the following description, a method for manufacturing a slurry for a positive electrode of a non-aqueous electrolyte secondary battery using an aqueous solvent containing an alkali metal composite oxide will be described.

First, in a state where the valve <NUM> is closed and the suction of the powder P via the powder supply pipe <NUM> is stopped, the mixing rotor <NUM> is driven to rotate while the pump <NUM> is operated, and the operation of the dispersion mixing pump <NUM> is started.

By operating the pump <NUM>, the solvent R is supplied from the storage tank <NUM> to the mixing chamber <NUM>. That is, at this time, only the solvent R is supplied to the mixing chamber <NUM> via the first supply unit <NUM>.

When the mixing rotor <NUM> is driven to rotate, the stirring blades <NUM> (see <FIG>) and the rotor blades <NUM> rotate integrally with the mixing rotor <NUM>.

As the rotor blades <NUM> rotate, the solvent R in the mixing chamber <NUM> is discharged from the discharge unit <NUM>. The discharged solvent R is supplied to the recirculation mechanism unit <NUM> via the discharge pipe <NUM>, and flows from the recirculation mechanism unit <NUM> to the second supply unit <NUM> through the circulation flow path <NUM>. Then, the solvent R is introduced into the mixing chamber <NUM> via the throttle portion <NUM> of the second supply unit <NUM>. Here, the flow path area of the throttle portion <NUM> is smaller than the flow path area of the discharge unit <NUM>. Therefore, the mixing chamber <NUM> is depressurized and enter a negative pressure state. Those that depressurize the mixing chamber <NUM>, that is, the mixing rotor <NUM>, the discharge unit <NUM>, the throttle portion <NUM>, and the rotor blades <NUM> are examples of a depressurization unit.

When the mixing chamber <NUM> is in a negative pressure state, the valve <NUM> is opened. Accordingly, the powder P stored in the hopper <NUM> is supplied from the lower opening portion <NUM> of the hopper <NUM> to the mixing chamber <NUM> by the negative pressure suction force of the mixing chamber <NUM>. The powder P and the solvent R are premixed in the first supply unit <NUM>, and a preliminary mixture Fp thereof is introduced into the annular groove <NUM>.

A step of supplying the solvent R and the powder P to the mixing chamber <NUM> described above is an example of a material supply step.

When the mixing rotor <NUM> is driven to rotate, the partition plate <NUM> rotates integrally with the mixing rotor <NUM>, and the scraping blades <NUM> revolve. At this time, the tip part <NUM> of the scraping blade <NUM> is in a state of being fitted into the annular groove <NUM>. Accordingly, the preliminary mixture Fp introduced into the annular groove <NUM> is scraped out by the tip part <NUM> of the scraping blade <NUM>. The scraped preliminary mixture Fp flows in the first introduction chamber <NUM> in the rotation direction of the mixing rotor <NUM>, passes through the through-holes <NUM>, and flows into the blade chamber <NUM>.

The preliminary mixture Fp introduced into the annular groove <NUM> undergoes a shearing action when scraped by the scraping blade <NUM>. Here, since the mixing chamber <NUM> is in a negative pressure state, there is a pressure difference between the inside and the outside of the mixing chamber <NUM>. Therefore, at this time, cavitation (local boiling) occurs in the preliminary mixture Fp located in the space behind the rear surface <NUM> (see <FIG>) of the rotor blade <NUM>.

That is, in the first introduction chamber <NUM>, a shearing force can be applied to the preliminary mixture Fp and cavitation (local boiling) can be generated. Therefore, the scraped preliminary mixture Fp undergoes the shearing action from the scraping blades <NUM> and the through-holes <NUM> and is mixed, and better dispersion of the powder P in the solvent R is achieved the cavitation (local boiling). Therefore, such a preliminary mixture Fp can be supplied to the blade chamber <NUM>, so that good dispersion of the powder P in the solvent R can be expected in the blade chamber <NUM>. Accordingly, the powder P and the solvent R are mixed to produce the slurry F.

Although cavitation was generated in the present embodiment, cavitation may not necessarily be generated as long as the powder P is preferably dispersed.

The preliminary mixture Fp that has flowed into the blade chamber <NUM> flows in the rotation direction of the mixing rotor <NUM> and is discharged as the slurry F from the discharge unit <NUM>. The slurry F discharged from the discharge unit <NUM> is supplied to the recirculation mechanism unit <NUM> through the discharge pipe <NUM>, and in the recirculation mechanism unit <NUM>, the undispersed slurry Fr is separated from the slurry F and bubbles of the solvent R are separated. The undispersed slurry Fr is supplied to the second supply unit <NUM> again via the circulation flow path <NUM>, and the slurry F and bubbles move to the storage tank <NUM> through the recovery pipe <NUM>.

The undispersed slurry Fr is introduced into the second introduction chamber <NUM> via the throttle portion <NUM> of the second supply unit <NUM> in a state where the flow rate thereof is limited. In the second introduction chamber <NUM>, the undispersed slurry Fr is subjected to the shearing action by the plurality of rotating stirring blades <NUM> (see <FIG>) and is further finely crushed. Furthermore, the undispersed slurry Fr is also subjected to the shearing action and is crushed when passing through the through-holes <NUM>. The undispersed slurry Fr is introduced into the blade chamber <NUM> via the through-holes <NUM> in a state where the flow rate thereof is limited. Then, in the blade chamber <NUM>, the slurry F, which is crushed by being subjected to the shearing action by the rotor blades <NUM> rotating at a high speed and the cavitation and is thus further reduced in the amount of agglomerates (lumps) of the powder P is mixed with the slurry F from the first introduction chamber <NUM> and is discharged from the discharge unit <NUM>.

When the supply of a predetermined amount of powder P from the hopper <NUM> is ended, the valve <NUM> is closed and the supply of the powder P to the mixing chamber <NUM> is stopped.

In this state, the operation of the dispersion mixing pump <NUM> is continued for a predetermined period of time. At this time, the slurry F replaced with the solvent R is supplied from the storage tank <NUM> to the mixing chamber <NUM>.

When the powder P is not supplied, air is not suctioned from the first supply unit <NUM>, so that the degree of vacuum in the mixing chamber <NUM> is increased. By rotating the rotor blades <NUM> in this state, at least the region in the blade chamber <NUM> can be made into a fine bubble region in which a large number of fine bubbles (microbubbles) of the solvent R are generated. Accordingly, the solvent R that has permeated the agglomerates (so-called lumps) of the powder P foams over the entire circumference in the blade chamber <NUM> to promote the crushing of the agglomerates, and furthermore, the dispersion of the powder P is further promoted by an impact force when the generated fine bubbles are pressurized and disappear in the blade chamber <NUM> or when the diameter of the bubbles becomes smaller. As a result, in almost the entire slurry F present in the entire circumference of the blade chamber <NUM>, it is possible to more reliably produce a high-quality slurry F in which the powder P is well dispersed in the solvent R.

A step of mix the solvent R and the powder P by driving the mixing rotor <NUM> described above is an example of a mixing step.

While continuing the operation of the dispersion mixing pump <NUM>, a supply step of supplying the reaction gas G to the slurry F produced in the mixing step is performed.

In the supply step, the valve <NUM> is opened after the operation of the dispersion mixing pump <NUM> is continued for a predetermined period of time. Accordingly, the reaction gas G stored in the cylinder <NUM> is supplied to the mixing chamber <NUM> by the negative pressure suction force of the mixing chamber <NUM>.

In the present embodiment, a timing at which the reaction gas G is supplied to the mixing chamber <NUM> is after the operation of the dispersion mixing pump <NUM> is continued for a predetermined period of time, that is, after the mixing step, but is not limited to this timing. For example, the timing at which the reaction gas G is supplied to the mixing chamber <NUM> may be a timing before the material supply step, or a timing after the material supply step and before the mixing step. In this case, by acidifying the water component of the solvent R in advance, it is possible to suppress rapid alkalization due to contact between lithium hydroxide contained in the slurry and water. Therefore, it is possible to suppress the production of a strongly alkaline slurry having a pH value of more than <NUM>, and thus it is possible to suppress the corrosion of the aluminum current collector during coating.

By supplying the reaction gas G to the mixing chamber <NUM>, the reaction gas G is supplied to the slurry F flowing through the mixing chamber <NUM>. Accordingly, the reaction gas G is dissolved in the slurry F. As a result, the alkaline component in the slurry F is neutralized.

Here, as described above, cavitation (local boiling) occurs in the slurry F located in the space behind the rear surface <NUM> of the rotor blade <NUM>. In the space, the slurry F is subjected to a neutralization treatment while generating cavitation (local boiling). Due to cavitation (local boiling), the bubbles of the reaction gas G repeatedly expand and contract, and the contact area with the solvent R or the slurry F increases, so that neutralization can proceed rapidly. Accordingly, it is possible to neutralize the alkaline component in the slurry F within a shorter period of time.

Through the supply step, in addition to the good dispersion of the powder P in the solvent R, it is possible to produce a higher quality slurry F in which the alkaline component is neutralized.

While the supply step is being performed, a circulation step described in detail below is performed.

In the circulation step, the pump <NUM> is driven. Accordingly, the surplus of the reaction gas G supplied to the mixing chamber <NUM> is suctioned and recovered by the pump <NUM> via the discharge pipe <NUM>, the recirculation mechanism unit <NUM>, the recovery pipe <NUM>, the storage tank <NUM>, and the intake pipe <NUM>.

Here, the surplus of the reaction gas G is, in the reaction gas G supplied to the mixing chamber <NUM> in the supply step, one that has not been dissolved in the slurry F and one that has been dissolved in the slurry F but has been subsequently degassed from the slurry F. The reaction gas G is degassed from the slurry F by operating the dispersion mixing pump <NUM> to cause cavitation (local boiling) in the slurry F in the mixing chamber <NUM>.

In addition, by driving the pump <NUM>, the suctioned reaction gas G is resupplied to the mixing chamber <NUM> via the gas resupply pipe <NUM>, the gas supply pipe <NUM> between the connection position P3 and the connection position P2, the slurry resupply pipe <NUM> between the connection position P2 and the connection position P1, and the first supply unit <NUM>.

By opening and closing the valve <NUM>, it is possible to switch whether or not the reaction gas G is resupplied to the mixing chamber <NUM>. Accordingly, it is possible to prevent an excessive resupply of the reaction gas G.

At least a portion of the reaction gas G resupplied to the mixing chamber <NUM> is dissolved in the slurry F and neutralizes the alkaline component in the slurry F.

In the present embodiment, the circulation step is executed while the supply step is being performed. That is, while the supply of the reaction gas G from the cylinder <NUM> to the mixing chamber <NUM> is performed, the surplus of the reaction gas G is resupplied to the mixing chamber <NUM> by the pump <NUM>. However, the circulation step may be performed after the supply step is performed. That is, when a predetermined amount of the reaction gas G is supplied from the cylinder <NUM> to the mixing chamber <NUM>, the valve <NUM> is closed to stop the supply, and thereafter the resupply of the surplus of the reaction gas G to the mixing chamber <NUM> by the pump <NUM> may be resumed. Furthermore, in a case where the circulation step is performed while the supply step is being performed, the circulation step may be continuously performed even if only the supply step is ended first.

The surplus of the reaction gas G supplied to the mixing chamber <NUM> by the gas supply unit <NUM> is recovered by the circulation unit <NUM> and resupplied to the mixing chamber <NUM>. Accordingly, at least a portion of the reaction gas G to be supplied to the mixing chamber <NUM> by the gas supply unit <NUM> can be replaced by the reaction gas G resupplied from the circulation unit <NUM>. As a result, the amount of the reaction gas G supplied to the mixing chamber <NUM> by the gas supply unit <NUM> can be reduced. Accordingly, the amount of the reaction gas G emitted to the outside can be reduced, so that the environmental load can be reduced.

The produced high-quality slurry F is supplied to subsequent steps via the discharge pipe <NUM> of the slurry F.

In the above embodiment, an example in which cavitation (local boiling) is generated to mix the powder P and the solvent R has been described. However, the powder P and the solvent R may be mixed only by stirring by rotating the mixing rotor <NUM> without generating cavitation (local boiling).

In the above embodiment, an example of mixing the powder P and the solvent R in a state where the mixing chamber <NUM> is depressurized has been described. However, the powder P and the solvent R may be mixed without depressurizing the mixing chamber <NUM> (for example, while maintaining the mixing chamber <NUM> at atmospheric pressure).

In the above embodiment, the reaction gas G is supplied to the first introduction chamber <NUM> of the mixing chamber <NUM>, but may also be supplied to other than the first introduction chamber <NUM> of the mixing chamber <NUM> (the second introduction chamber <NUM> or the blade chamber <NUM>).

Filters for preventing the powder P from erroneously reaching the pump <NUM> may be provided in the intake pipe <NUM>, the gas port <NUM>, the suction port <NUM>, and the like. The filter is, for example, a semipermeable membrane that restricts the passage of liquids and solids and allows the passage of gases.

In the above embodiment, the slurry manufacturing apparatus <NUM> has a configuration as illustrated in <FIG>. The slurry manufacturing apparatus <NUM> illustrated in <FIG> is for external circulation, and the solvent R and the slurry F stored in the storage tank <NUM> are supplied to the first supply unit <NUM> of the dispersion mixing pump <NUM> via the slurry resupply pipe <NUM>. However, the slurry manufacturing apparatus <NUM> is not limited to the configuration illustrated in <FIG>. For example, the slurry manufacturing apparatus <NUM> may be for internal circulation as illustrated in <FIG>. In the slurry manufacturing apparatus <NUM> illustrated in <FIG>, the solvent R and the slurry F stored in the storage tank <NUM> are supplied to the second supply unit <NUM> of the dispersion mixing pump <NUM> via a supply pipe <NUM>.

In the above embodiment, the slurry F is a slurry for a positive electrode of a non-aqueous electrolyte secondary battery using an aqueous solvent containing an alkali metal composite oxide. The powder P is a predetermined slurry material used for manufacturing an electrode for a non-aqueous electrolyte secondary battery, the solvent R is water, and the reaction gas G is carbon dioxide gas.

<FIG> illustrates a slurry manufacturing apparatus <NUM> according to a second embodiment of the present invention. The second embodiment illustrated in <FIG> is characterized in that in addition to the configuration of the first embodiment, a first pressure gauge <NUM>, a second pressure gauge <NUM>, and a control unit <NUM> are provided, and the control unit <NUM> controls the pump <NUM> based on the values of the first pressure gauge <NUM> and the second pressure gauge <NUM>. The description of the same configuration as that of the first embodiment will be omitted.

The first pressure gauge <NUM> is provided in the recovery pipe <NUM> and measures the pressure in the recovery pipe <NUM>. The second pressure gauge <NUM> is provided in the storage tank <NUM> and measures the pressure in the storage tank <NUM>. The kind, material, and the like of the first pressure gauge <NUM> and the second pressure gauge <NUM> are not limited as long as the pressure can be measured.

In the supply step of the first embodiment, the reaction gas G is supplied from the gas supply unit <NUM> to the slurry F, but the reaction gas G that has not been dissolved in the slurry F is collected in the storage tank <NUM> during the introduction or suspension of the introduction of the reaction gas G, whereby the pressure in the storage tank <NUM> increases. When the pressure in the storage tank <NUM> becomes higher than the pressure in the recovery pipe <NUM>, there may be cases where the slurry does not flow through the recovery pipe <NUM>.

Therefore, in the slurry manufacturing apparatus <NUM> according to the second embodiment, the pressure in the recovery pipe <NUM> and the pressure in the storage tank <NUM> are respectively measured by using the first pressure gauge <NUM> and the second pressure gauge <NUM>, so that a state where the slurry F flows can be measured. In a case where the pressure in the storage tank <NUM> becomes higher than the pressure in the recovery pipe <NUM>, an unreacted gas in the storage tank <NUM> is circulated through the gas resupply pipe <NUM> to the mixing chamber <NUM> by driving the pump <NUM>. Accordingly, the pressure in the storage tank <NUM> is reduced, and the slurry can flow through the recovery pipe <NUM>.

The first pressure gauge <NUM> may measure the pressure in front of the storage tank <NUM>, and may be installed, for example, in the cylindrical container <NUM>. The second pressure gauge <NUM> may measure the pressure after the storage tank <NUM>, and may be installed, for example, in the intake pipe <NUM>.

The control unit <NUM> is electrically connected to the first pressure gauge <NUM>, the second pressure gauge <NUM>, and the pump <NUM> to control the pump <NUM> based on the measurement results of the first pressure gauge <NUM> and the second pressure gauge <NUM>, and may be, for example, a computer. The control unit <NUM> is not limited to a computer and may perform control by another method. For example, manual control by an observer or the like can be considered.

By performing control by the control unit <NUM>, the pressures in the recovery pipe <NUM> and the storage tank <NUM> can be controlled more accurately and quickly, and the slurry can be efficiently flowed to the recovery pipe <NUM>.

<FIG> illustrates a slurry manufacturing apparatus <NUM> according to a third embodiment of the present invention. The third embodiment illustrated in <FIG> is characterized in that, in addition to the configuration of the second embodiment, a gas recovery tank <NUM> and a check valve <NUM> are provided. The description of the same configuration as that of the second embodiment will be omitted.

The gas recovery tank <NUM> recovers the surplus of the reaction gas G in the recovery pipe <NUM>, and is installed in the gas resupply pipe <NUM>. In addition, the gas recovery tank <NUM> may be installed anywhere as long as the surplus of the reaction gas G in the recovery pipe <NUM> can be recovered, and may be installed, for example, in the recovery pipe <NUM> or the intake pipe <NUM>. The kind, material, size, and the like of the gas recovery tank <NUM> are not limited as long as the gas recovery tank <NUM> has a valve capable of recovering a gas and allowing the gas to pass therethrough as appropriate.

The check valve <NUM> is backflow preventing means for preventing the unreacted gas recovered in the gas recovery tank <NUM> from flowing back into the storage tank <NUM> by the check valve <NUM>, and the kind, material, and the like thereof are not limited as long as the backflow of the unreacted gas recovered in the gas recovery tank <NUM> can be prevented. Specific examples of the check valve include a ball type check valve and a noval type check valve.

In addition, the check valve <NUM> may be installed anywhere as long as the unreacted gas recovered in the gas recovery tank <NUM> can be prevented from flowing back to the storage tank <NUM>, and may be installed, for example, at a connection portion between the gas recovery tank <NUM> and the gas resupply pipe <NUM>, or on the storage tank <NUM> side of the gas resupply pipe <NUM>.

The backflow preventing means may be other than the check valve. For example, the backflow preventing means may be means for preventing backflow by continuously driving the pump <NUM>, or means for preventing backflow by closing a valve and stopping the outflow of the unreacted gas stored in the gas recovery tank <NUM>.

In the slurry manufacturing apparatus <NUM> according to the third embodiment, when the pump <NUM> is driven and the pressure in the storage tank <NUM> is reduced, the unreacted gas discharged from the storage tank <NUM> can be recovered in the recovery tank <NUM>. The unreacted gas recovered in the recovery tank <NUM> is supplied to the dispersion mixing pump <NUM> as needed by opening and closing the valve <NUM> installed on the downstream side. Furthermore, since a negative pressure state is established between the connection position P2 and the connection position P1 of the slurry resupply pipe <NUM> by driving the dispersion mixing pump <NUM>, when the valve <NUM> is opened, the unreacted gas is naturally supplied from the recovery tank <NUM> to the dispersion mixing pump <NUM>.

Claim 1:
A slurry manufacturing apparatus comprising:
a powder supply unit (<NUM>) configured to supply a predetermined powder to a mixing chamber (<NUM>);
a solvent supply unit (<NUM>) configured to supply a solvent to the mixing chamber (<NUM>),
a mixing unit (<NUM>) configured to mix the predetermined powder and the solvent in the mixing chamber (<NUM>) to produce a slurry;
a gas supply unit (<NUM>) configured to supply a reaction gas to the mixing chamber (<NUM>) when the slurry is produced by the mixing unit (<NUM>); and
a circulation unit (<NUM>) configured to recover a surplus of the reaction gas from the mixing chamber (<NUM>) and resupply the surplus of the reaction gas to the mixing chamber (<NUM>);
a storage unit (<NUM>) configured to recover the slurry produced in the mixing chamber (<NUM>) and store the slurry,
wherein the circulation unit (<NUM>) has a first pipe (<NUM>, <NUM>) that connects the mixing chamber (<NUM>) to the storage unit (<NUM>), and that is configured to recover the slurry and the surplus of the reaction gas from the mixing chamber (<NUM>) to the storage unit (<NUM>), and a second pipe (<NUM>, <NUM>) that connects the storage unit (<NUM>) to the mixing chamber (<NUM>), and that is configured to supply the surplus of the reaction gas from the storage unit (<NUM>) to the mixing chamber (<NUM>);
wherein the mixing unit (<NUM>) is configured to rotate a mixing rotor (<NUM>) in the mixing chamber (<NUM>) to produce the slurry, and
the first pipe (<NUM>, <NUM>) is connected to the mixing chamber (<NUM>) such that the slurry is introduced into the first pipe (<NUM>, <NUM>) along a flow of the slurry formed by the rotation of the mixing rotor (<NUM>).