KR101615781B1 - Manufacturing apparatus for positive active material and mixing apparatus - Google Patents

Abstract

The present invention relates to an apparatus for producing a cathode active material and a stirring apparatus provided therein. The present invention relates to a pre-mixer for stirring an iron solution and a lithium solution which are fed into the same line or different lines; A main mixer in which a mixed solution and supercritical water are mixed and stirred in a pre-mixer; And a reactor for producing a cathode active material through a supercritical reaction of the mixed mixture in the main mixer, wherein the pre-mixer is composed of a homo-mixer and stirs the iron solution and the lithium solution introduced therein . According to the present invention, since the iron solution and the lithium solution are mixed with the supercritical water in a premixed state in the pre-mixer, it is possible to prevent the Fe salt from being precipitated to block the input line, It is possible to effectively stir the iron solution and the lithium solution.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positive electrode active material production apparatus and a stirring apparatus,

The present invention relates to an apparatus for producing a cathode active material and a stirring apparatus provided therein, and more particularly, to an apparatus for producing a cathode active material and a stirring apparatus for the same which are preliminarily mixed with a preliminary mixer capable of effectively mixing an iron solution and a lithium solution The present invention also relates to an apparatus for manufacturing a cathode active material and a stirring apparatus provided therein.

As the development and demand for portable electronic devices such as mobile devices have increased, the demand for secondary batteries as energy sources has been rapidly increasing. Among these secondary batteries, high energy density and voltage, long cycle life, Low lithium secondary batteries have been commercialized and widely used.

Particularly, the lithium secondary battery has a working voltage of 3.6 V or higher, which is three times higher than a nickel-cadmium battery or a nickel-hydrogen battery which is widely used as a power source for portable electronic devices, and is rapidly expanded in terms of high energy density per unit weight There is a trend.

The lithium secondary battery is manufactured by using a material capable of inserting and desorbing lithium ions as a cathode and an anode, filling an organic electrolyte or a polymer electrolyte between the anode and the cathode, and inserting and removing lithium ions from the anode and the cathode. And generates electrical energy by oxidation and reduction reactions when they are desorbed.

In such a lithium secondary battery, a transition metal oxide having a layered or spinel structure is used as a cathode active material, and recently, a lithium transition metal phosphate cathode active material having excellent safety has been extensively studied.

Lithium transition metal phosphate materials are classified into LixM ₂ (PO ₄ ) ₃ , which is a Nasicon structure, and LiMPO ₄ , which has an olivine structure, and has been studied as a material superior in high temperature stability to LiCoO ₂ .

The current tank top cone structure of _{Li 3 V 2 (PO 4)} 3 (Saphion) the material of the blank structure compound in the development, olivine structure, and is by Valence four are LiFePO ₄ and Li (Mn, Fe) PO ₄ post It is the most widely researched.

In particular, the olivine-structured lithium iron phosphate (LiFePO ₄ ) has a high theoretical capacity of 170 mAh / g, superior high-temperature stability, and low Fe use despite its somewhat low voltage disadvantage of ~ 3.4 V vs. lithium There is a possibility of being applied to a cathode active material of a lithium secondary battery and a lot of research has been conducted as a cathode active material of a lithium ion secondary battery for a hybrid electric vehicle (HEV).

FIG. 1 is a view showing a solution and supercritical water are stirred by a conventional technique.

As shown, the solution reacts with the supercritical water for the preparation of the lithium secondary battery cathode active material. That is, the lithium solution and the iron solution are injected along the lithium solution line 2 and the iron solution line 3, respectively, on both sides of the supercritical water line 1 through which supercritical water passes.

At this time, when the temperature of the iron solution is raised due to the high temperature of the supercritical water (about 400 ° C.), the solubility of the iron solution is decreased, so that the Fe salt precipitates and the end of the iron solution line 3 A clogging problem may occur. If the Fe salt is precipitated in this manner, the iron solution can not be supplied normally and there is a problem that the iron solution must be removed by using a tool such as a hammer or an awl.

It is therefore an object of the present invention to solve the problems of the prior art as described above, and it is an object of the present invention to prevent precipitation of Fe salts due to a supercritical water at a high temperature in a solution feed line, And a stirring device provided in the apparatus.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not intended to limit the invention to the precise forms disclosed. Other objects, which will be apparent to those skilled in the art, It will be possible.

According to an aspect of the present invention, there is provided a lithium ion secondary battery comprising: a premixer for stirring an iron solution and a lithium solution which are introduced into the same line or different lines; A main mixer in which the solution mixed in the pre-mixer and the supernatant coefficient are mixed and stirred; And a reactor for producing a cathode active material through a supercritical reaction of the mixed mixture in the main mixer, wherein the pre-mixer is composed of a homo-mixer and is characterized in that the introduced iron solution and lithium solution are stirred .

Wherein the pre-mixer comprises: an agitating vessel into which the iron solution and the lithium solution are introduced; An agitator for providing power required for stirring; A rotor installed on a rotating shaft of the stirrer and rotated by receiving power from the stirrer; And a stator which is fixed so as to be spaced apart from the rotor and stirs the iron solution and the lithium solution introduced together with the rotor.

And a cutter protruding from the opposite surfaces of the rotor and the stator.

And the rotor is rotated at 8500 rpm or more.

And the mixed solution in the stirring vessel is discharged at an intermediate portion of the height of the stirring vessel.

And a filter for filtering the powder of the cathode active material produced in the reactor.

Water reservoir; A heat exchanger for exchanging heat between the water supplied from the water storage tank and the mixture mixed in the main mixer to bring the mixture into a high temperature state; And a heater for heating the water passing through the heat exchanger to produce supercritical water.

And a cooling device for preventing the inflow of heat generated in the supercritical water is installed in the mixed solution line connecting the premixer and the main mixer.

The cathode active material is an olivine-structured LiMPO ₄ .

According to the present invention, since the iron solution and the lithium solution meet with the supercritical water in the premixed state in the pre-mixer, the Fe salt can be prevented from being deposited and blocking the input line. Therefore, there is no need to separately perform the operation of depositing the Fe salt deposited on the input line, and the cathode active material can be manufactured more smoothly, thereby improving the quality of the product.

In addition, there is an effect that the iron solution and the lithium solution can be effectively stirred through a strong agitation force by using a homomixer.

1 is a schematic view showing that a solution and supercritical water are stirred by a conventional technique;
2 is a process diagram showing an apparatus for producing a cathode active material according to an embodiment of the present invention.
3 is a view showing an embodiment of a pre-mixer according to the present invention.

Hereinafter, an apparatus for producing a cathode active material according to the present invention and a stirring apparatus provided therein will be described in detail with reference to the accompanying drawings.

FIG. 2 is a process diagram showing a manufacturing apparatus for a cathode active material according to an embodiment of the present invention, and FIG. 3 is a view illustrating an embodiment of a pre-mixer according to the present invention.

According to the present invention, the cathode active material according to the present invention is prepared by reacting a mixed solution of an iron solution and a lithium solution with a supercritical water. First, the iron solution and the lithium solution stored in the iron solution reservoir 5 and the lithium solution reservoir 6 respectively flow into the pre-mixer 10 through different lines. In FIG. 2, the iron solution and the lithium solution are shown as being introduced into different lines. However, the present invention is not limited thereto. The iron solution and the lithium solution may flow into the same line.

The pre-mixer 10 serves to pre-mix the iron solution and the lithium solution in order to prevent the Fe salt from being precipitated on the line due to the decrease in solubility due to the supercritical state of the iron solution at high temperature. When the iron solution and the lithium solution are stirred, FePO ₄ -type Phosphrous Fe salt is produced without generating any Fe salt. The Fe salt of phosphoric acid is less hardenable to heat than FeSO ₄ and can prevent the solution input line from being clogged by the Fe salt because it is not precipitated in the mid-temperature range (about 300 ° C). That is, in the pre-mixer 10, the iron solution and the lithium solution are thoroughly stirred sufficiently to prepare a phosphate salt of Fe, so as to meet the supercritical water coefficient in the main mixer 20 to be described later.

FIG. 3 is a block diagram showing an embodiment of a pre-mixer according to the present invention. Referring to this, it is preferable to use a homo-mixer as the pre-mixer 10. The homomixer is a device that mechanically destroys tissues or cells to make or emulsify the particles.

The iron solution and the lithium solution (hereinafter referred to as " mixed solution ") introduced into the pre-mixer 10 made of a homomixer have a gel form. Particles are small in the premixer 10 through strong agitation The standard deviation of the particle is also small and the particle size distribution becomes narrow and can be slurried.

The outer appearance of the pre-mixer 10 is an agitating vessel 11, and an agitator 12 installed inside or outside the agitating vessel 11 provides the power necessary for stirring. That is, the rotor 14 is provided at the end of the rotating shaft 13 of the stirrer 12 and the rotor 14 is rotated by the driving of the stirrer 12. Here, the rotor 14 is preferably rotated at a high-speed rpm of 8500 rpm or more. Since the retention time at which the rotor 14 uniformizes the particles at a low speed of 8,500 rpm or less is insufficient, the stirring vessel 11 must be large or the flow rate to be supplied must be small. As the agitating vessel 11 becomes smaller and the flow rate of the feed is increased, the particles may become uneven in the supercritical reaction. This leads to a decrease in the electrode performance due to the reduction of the electrode surface area in the production as the anode electrode.

Although the rotor 14 is shown as being installed at the end of the rotary shaft 13 in the present embodiment, two or more of the rotor 14 may be provided in multiple layers depending on the size of the stirring container 11, stirring conditions, and the like.

Further, the stator 15 is fixedly installed so as to be spaced apart from the rotor 14 by a predetermined distance. The stator 15 serves to stir the mixed solution introduced into the stirring vessel 11 together with the rotor 14. Concretely, the mixed solution flowing into the stirring vessel 11 is sucked into the space between the rotor 14 and the stator 15 by the strong rotating force of the rotor 14 and stirred. In this process, the gel-like mixed solution is converted into a slurry form.

On the surfaces of the rotor 14 and the stator 15 facing each other, a cutter 16 for stirring the mixed solution is formed. The cutter 16 protrudes in the circumferential direction in a staggered manner, as shown in FIG. 3, to slurry the mixed solution introduced therebetween.

The configuration of the pre-mixer 10 described above is an example of a homo mixer, and various types of homo-mixers as well as the pre-mixer 10 in this embodiment can be used.

The mixed solution introduced into the lower portion of the stirring vessel 11 is discharged to the side. At this time, it is preferable that the portion where the mixed solution is discharged is the middle portion of the height of the stirring vessel 11. This is because a strong suction is generated at the lower part of the homomixer when stirring, and circulation is performed. When the homomixer is discharged to the bottom of the homomixer, the circulation speed is the fastest part. This is because there is a possibility that it will not escape. On the contrary, if the mixed solution is discharged to the upper end of the homomixer, it is easy to discharge, but the middle portion of the height of the stirring vessel 11 is most preferable because the powder can penetrate and break the motor when mounting the motor.

It is preferable that the mixed solution staying in the stirring vessel 11 is at least 1 minute. This is because the iron solution and the lithium solution must remain in the agitating vessel 11 for more than a predetermined time to be sufficiently slurried.

A mixed solution line (17) is connected to a portion where the mixed solution is discharged from the stirring vessel (11). Since the mixed solution line 17 is connected to the main mixer 20 side, the mixed solution introduced through the mixed solution line 17 is mixed with the supercritical water in the main mixer 20.

A cooling device 18 is provided between the pre-mixer 10 and the main mixer 20 to prevent the heat generated from the supercritical water from flowing into the pre-mixer 10 and the main mixer 20. The cooling device 18 serves to prevent the heat generated from the supercritical water at a high temperature from flowing into the premixer 10. In other words, the cooling device 18 is installed in the mixed solution line 17 shown in FIG. 3 and cooled. An example of the cooling device 18 is a cooling pipe in the form of a double pipe tube.

Next, the solution stirred in the main mixer 20 is introduced into the reactor 30. In the reactor 30, a supercritical reaction is performed under a high-temperature and high-pressure condition, and lithium iron phosphate (LiFePO ₄ ) can be produced. Here, the mixed solution has a temperature of about 20 ° C and a supercritical water temperature of about 400 ° C, and a product having a temperature of about 374 ° C to about 383 ° C is produced.

Since the product obtained through the supercritical reaction contains powder, it is introduced into the filter 32 to filter it. The product filtered by the filter 32 is stored in the product storage tank 34.

On the other hand, the water stored in the water storage tank 7 is heat-exchanged with the mixture mixed in the main mixer 20 through the heat exchanger 22, is raised to about 300 ° C, and is introduced into the heater 24. Is raised to a temperature (about 400 DEG C) necessary for the supercritical reaction in the heater 24 and is moved to the main mixer 20 side.

As described above, in the present invention, the supercritical reaction is used to prepare the cathode active material and the supercritical water is mixed with the iron solution and the lithium solution at the same time, So that the supercritical reaction can be performed more smoothly.

Although lithium iron phosphate is described as a cathode active material in this embodiment, it is not necessarily limited thereto, and any material may be used as long as it is an olivine structure of LiMPO ₄ .

The scope of the present invention is not limited to the embodiments described above, but may be defined by the scope of the claims, and those skilled in the art may make various modifications and alterations within the scope of the claims It is self-evident.

5: iron solution reservoir 6: lithium solution reservoir
7: water storage tank 10: pre-mixer
11: Stirring vessel 12: Stirrer
13: rotating shaft 14: rotor
15: stator 16: cutter
17: mixed solution line 18: cooling device
20: main mixer 22: heat exchanger
24: heater 30: reactor
32: filter 34: product storage tank

Claims (14)

A pre-mixer for stirring the iron solution and the lithium solution which are introduced into the same line or different lines;
A main mixer in which the solution mixed in the pre-mixer and the supernatant coefficient are mixed and stirred; And
And a reactor for producing a cathode active material through a supercritical reaction of the mixed mixture in the main mixer,
Wherein the pre-mixer comprises a homo-mixer and stirs the introduced iron solution and the lithium solution. The apparatus of claim 1, wherein the pre-
A stirring vessel into which the iron solution and the lithium solution are introduced;
An agitator for providing power required for stirring;
A rotor installed on a rotating shaft of the stirrer and rotated by receiving power from the stirrer; And
And a stator which is fixed so as to be spaced apart from the rotor and stirs the iron solution and the lithium solution introduced together with the rotor. 3. The method of claim 2,
Wherein a cutter protrudes from the opposite surfaces of the rotor and the stator so as to be offset from each other. 3. The method of claim 2,
Wherein the rotor is rotated at 8500 rpm or more. 3. The method of claim 2,
Wherein the mixed solution in the stirring vessel is discharged at an intermediate portion of the height of the stirring vessel. The method according to claim 1,
Further comprising a filter for filtering the powder of the cathode active material produced in the reactor. The method according to claim 1,
Water reservoir;
A heat exchanger for exchanging heat between the water supplied from the water storage tank and the mixture mixed in the main mixer to bring the mixture into a high temperature state; And
Further comprising a heater for heating the water passing through the heat exchanger to produce supercritical water. The method according to claim 1,
Wherein a cooling device is installed in the mixed solution line connecting the pre-mixer and the main mixer to prevent the heat generated from the supercritical water from flowing into the mixed solution line. 9. The method according to any one of claims 1 to 8,
The cathode active material is an olivine-structured LiMPO ₄ Wherein the positive electrode active material is a positive electrode active material. delete delete delete delete delete

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