KR20120097700A - Manufacturing apparatus for positive active material using sedimentation - Google Patents

Abstract

PURPOSE: A manufacturing apparatus for positive electrode active material is provided to improve energy efficiency in manufacturing positive electrode active material because additional heat energy for heat-exchange is not required by putting water of high temperature separated from a sedimentation tank into a heat exchanger. CONSTITUTION: A manufacturing apparatus for positive electrode active material comprises: a stirrer stirring iron solution and lithium solution, and supercritical water; a heater(14) making a supercritical state by heat-exchanging with water before a supercritical state; a reactor(20) generating a positive electrode active material through a supercritical reaction of a mixture mixed in the stirrer; a precipitation tank(25) separating to water and powder of high temperature through precipitation by putting an outcome in the reactor; and a heat exchanger installed in a front end of the heater, heat-exchanging with the water separated from the precipitation tank, and heat-exchanging with the water before supercritical state.

Description

Manufacturing apparatus for positive active material using sedimentation {Manufacturing apparatus for positive active material using sedimentation}

The present invention relates to an apparatus for manufacturing a cathode active material, and more particularly, to separate the reactants produced in the supercritical process into hot water and powder using sedimentation, and the separated water may be introduced into a heat exchanger to increase energy efficiency. The present invention relates to an apparatus for producing a positive electrode active material using sedimentation.

As the development and demand of technology for portable electronic devices such as mobile devices increases, the demand for secondary batteries as a source of energy is rapidly increasing. Among these secondary batteries, the secondary batteries have high energy density and voltage, have long cycle life, and have a high self discharge rate. Low lithium secondary batteries have been commercialized and widely used.

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

In addition, a lithium secondary battery is prepared by using a material capable of inserting and detaching lithium ions as a negative electrode and a positive electrode, and filling an organic electrolyte or a polymer electrolyte between the positive electrode and the negative electrode, and lithium ions are inserted into the positive electrode and the negative electrode. Electrical energy is generated by oxidation and reduction reactions when desorption.

In the 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 widely studied.

Lithium transition metal phosphate materials are classified into Naxicon-structured LixM ₂ (PO ₄ ) ₃ and Olivine-structured LiMPO ₄ , and have been studied as excellent materials at high temperature stability compared to LiCoO ₂ . .

Currently, Na ₃ Si ₃ Li ₂ V ₂ (PO ₄ ) ₃ (Saphion) has been developed by Valence, and among the olivine compounds, LiFePO ₄ and Li (Mn, Fe) PO ₄ olivine structure materials Most widely studied.

In particular, the lithium iron phosphate (LiFePO ₄ ) of the olivine structure has a high theoretical capacity of 170 mAh / g, excellent high temperature stability, and low-cost Fe, despite the disadvantage of a relatively low voltage of ~ 3.4 V compared to lithium. There is applicability as a lithium secondary battery positive electrode active material, and much research has been made as a positive electrode active material of a lithium ion secondary battery for a hybrid electric vehicle (HEV).

Such a positive electrode active material may be manufactured through a supercritical process, and the heat exchange efficiency is low in the heat exchanger for raising the water to a high temperature in the supercritical process, resulting in a problem of lowering the overall energy efficiency.

Therefore, an object of the present invention is to solve the problems of the prior art as described above, using sedimentation having a structure that can easily separate the hot water and powder using sedimentation and heat exchange through the separated water. It is to provide an apparatus for producing a positive electrode active material.

Technical problems to be achieved by the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned above will be clearly understood by those skilled in the art from the following description. Could be.

According to a feature of the present invention for achieving the object as described above, the present invention is an iron solution and a lithium solution, a supercritical water joining and stirring apparatus; A heater, which heat-exchanges with the water before the supercritical state and makes the supercritical state; A reactor for producing a positive electrode active material through a supercritical reaction of the mixture mixed in the stirring apparatus; A settling tank in which the reactants generated in the reactor are input and separated into hot water and powder by the settling action; And a heat exchanger in which high temperature water separated from the sedimentation tank is inputted to perform heat exchange, and installed at a front end of the heater to exchange heat with water before a supercritical state.

The stirring device may include a premixer for stirring the iron solution and the lithium solution into different lines; And a main mixer in which the solution mixed in the premixer and the supercritical water are joined and stirred.

The tank input line introduced into the sedimentation tank is connected to the sedimentation tank downwardly.

It characterized in that it further comprises a cooling tank for cooling and diluting the powder separated from the sedimentation tank using the stored cooling water.

The cooling water is added to a volume three times or more of the powder, characterized in that to dilute the powder.

It is installed on the rear end of the cooling tank characterized in that it further comprises a filter for filtering the powder.

It is installed on the rear end of the filter, characterized in that it further comprises a back pressure regulator for maintaining a constant pressure of the fluid.

The cooling tank is further characterized in that the auxiliary cooling device for auxiliary cooling of the powder introduced from the sedimentation tank.

The cathode active material is LiMPO ₄ of the olivine structure It is characterized by that.

According to another feature of the invention, the present invention is a premixer for stirring the iron solution and lithium solution to be introduced into different lines; A main mixer in which the solution mixed in the premixer and the supercritical water are joined and stirred; A heater, which heat-exchanges with the water before the supercritical state and makes the supercritical state; A reactor for producing a positive electrode active material through a supercritical reaction of the mixture mixed in the main mixer; A settling tank in which the reactants generated in the reactor are input and separated into hot water and powder by the settling action; A cooling tank for cooling and diluting the powder separated from the sedimentation tank by using the stored cooling water; And a heat exchanger in which high temperature water separated from the sedimentation tank is inputted to perform heat exchange, and installed at a front end of the heater to exchange heat with water before a supercritical state.

According to the present invention, since the high-temperature water separated from the sedimentation tank is introduced into the heat exchanger so that no additional heat energy is required for heat exchange, energy efficiency is improved in the production of the positive electrode active material.

In addition, by cooling the powder separated from the sedimentation tank using cooling water, the purity of the reactant discharged is increased, thereby improving quality.

1 is a block diagram of an apparatus for manufacturing a cathode active material using sedimentation according to an embodiment of the present invention.

Hereinafter will be described in detail with reference to the accompanying drawings an embodiment of an apparatus for producing a positive electrode active material using the sedimentation according to the present invention.

1 is a block diagram of an apparatus for manufacturing a cathode active material using sedimentation according to an embodiment of the present invention.

As shown, the positive electrode active material according to the present invention is prepared by reacting a supercritical water with a solution in which an iron solution and a lithium solution are mixed. First, the iron solution and the lithium solution respectively stored in the iron solution reservoir 1 and the lithium solution reservoir 2 are introduced into the premixer 4 through different lines.

The pre-mixer (4, Pre-mixer) serves to stir the iron solution and the lithium solution in advance to prevent the Fe salt is precipitated on the line by reducing the solubility due to the supercritical water in the iron solution is a high temperature state. When the iron solution and the lithium solution are agitated, independent Fe salts do not occur and form a FePO ₄ form of phosphate Fe salt. The Fe phosphate salt is less hard to heat than FeSO ₄ and does not precipitate in the middle temperature region (about 300 ° C), thereby preventing the solution input line from being blocked by the Fe salt. That is, in the premixer 4, the iron solution and the lithium solution are sufficiently stirred in advance to form Fe phosphate salt so as to meet the supercritical water in the main mixer 6 which will be described below.

In the above description, the premixer 4 and the main mixer 6 have been described as a stirring device for stirring the iron solution and the lithium solution and the supercritical water, but the present invention is not limited thereto. The supercritical water may be configured to be stirred.

Meanwhile, the water stored in the water storage tank 10 undergoes heat exchange while passing through the heat exchanger 12. At this time, the heat exchange in the heat exchanger 12 may be made of hot water separated from the sedimentation tank 25 to be described later without additional thermal energy. That is, heat transferred from the high temperature water separated from the sedimentation tank 25 is transferred to the water introduced from the water storage tank 10, and the water is raised to about 300 ° C. and introduced into the heater 14. The heater 14 is raised to a temperature (about 400 ° C.) necessary for the supercritical reaction, and the water made in the supercritical state is moved to the main mixer 6 to be stirred with the iron solution and the lithium solution.

Next, the stirred solution in the main mixer 6 is introduced into the reactor 20. In the reactor 20, a supercritical reaction may be performed under conditions of high temperature and high pressure, and lithium iron phosphate (LiFePO ₄ ) may be generated. Here, the mixed solution is about 20 ℃, the supercritical water meets about 400 ℃ to produce a product having a temperature of about 374 to 383 ℃.

The reactants produced through the supercritical reaction are introduced into the settling tank 25 along the tank input line 22. At this time, the tank input line 22 is inclined downward with respect to the settling tank 25, which is to use a sufficient deposition speed of the fluid as using the cyclone principle.

Here, the reactants consist of hot water and powder. Therefore, water and powder having a low flow rate in the sedimentation tank 25 are naturally separated by the sedimentation action, and the powder sinks to the lower portion of the sedimentation tank 25. At this time, the flow rate of the reactant introduced into the sedimentation tank 25 is, for example, so that the total solid content (TSC: Total solid content), that is 4.6 cm / s or less when the content of the powder contained in the total slurry is 10% It is desirable to adjust. This is because if the flow rate of the reactants exceeds 4.6 cm / s, the powder may escape in a mixed state with water without settling. In addition, if the total solids content exceeds 10%, the flow rate of the reactants should be designed to lower the sedimentation of the powder. The flow rate of the reactants described above is possible through a design for appropriately adjusting the height and diameter of the sedimentation tank (25).

Then, the hot water in which the powder is filtered is introduced into the heat exchanger 12 along the line ⓐ of FIG. 1. The hot water introduced into the heat exchanger 12 undergoes heat exchange with the water stored in the water storage tank 10.

On the other hand, the powder filtered in the settling tank 25 is discharged along the tank discharge line (26). The discharged powder meets the cooling water in the cooling tank 32 to lower the temperature. Cooling water introduced into the cooling tank 32 is stored in the cooling water storage tank 30. The cooling water is added to a volume three times or more of the powder to cool and dilute the powder. In this embodiment, the powder meets the cooling water to be cooled and diluted because the product discharged through quenching (quenching, a kind of quenching through rapid cooling) may increase the purity.

In addition, one side of the cooling tank 32 may be further provided with an auxiliary cooling device 33 for auxiliary cooling of the powder introduced from the settling tank 25. An example of the auxiliary cooling device 33 is a cooling jacket in the form of a double pipe tube.

On the other hand, the powder obtained through the supercritical reaction is filtered by a filter 34 installed at the rear end of the cooling tank 32. In addition, the product filtered out of the filter 34 is stored in the product reservoir 38. In addition, a back pressure regulator 36 is provided at the rear end of the filter 34 to maintain a constant pressure of the fluid during the operation of the apparatus for manufacturing the cathode active material.

As described above, in the present embodiment, it is possible to increase energy efficiency by utilizing high temperature water separated from the sedimentation tank 25 without inputting additional heat energy for heat exchange of water stored in the water storage tank 10, and sedimentation. Powder separated in the tank 25 has the advantage that can produce a high purity product through the cooling and dilution action in the cooling tank (32).

In addition, the present embodiment has been described using lithium iron phosphate as an example of the positive electrode active material, but is not necessarily limited thereto, and any material may be applied to LiMPO _{4 having} an olivine structure.

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.

1: iron solution reservoir 2: lithium solution reservoir
4: Premixer 6: Main Mixer
10: water reservoir 12: heat exchanger
14 heater 20 reactor
22: tank input line 25: sedimentation tank
26: tank discharge line 30: cooling water storage tank
32: cooling tank 33: auxiliary cooling device
34 filter 36 back pressure regulator
38: product reservoir

Claims (18)

An agitating device in which the iron solution and the lithium solution and the supercritical water are joined and stirred;
A heater, which heat-exchanges with the water before the supercritical state and makes the supercritical state;
A reactor for producing a positive electrode active material through a supercritical reaction of the mixture mixed in the stirring apparatus;
A settling tank in which the reactants generated in the reactor are input and separated into hot water and powder by the settling action; And
High temperature water separated from the sedimentation tank is introduced into the heat exchange, and the apparatus for producing a positive electrode active material using the sedimentation, characterized in that it comprises a heat exchanger is installed in the front of the heater to exchange heat with water before the supercritical state . The method of claim 1, wherein the stirring device,
A premixer for stirring the iron solution and the lithium solution introduced into different lines; And
Apparatus for producing a positive electrode active material using the sedimentation, characterized in that it comprises a main mixer which is stirred by mixing the solution and the supercritical water mixed in the premixer. The method of claim 1,
Tank inlet line is introduced into the sedimentation tank manufacturing apparatus of the positive electrode active material using sedimentation, characterized in that connected to the sedimentation tank inclined downward. The method of claim 1,
Apparatus for producing a positive electrode active material using the sedimentation tank further comprises a cooling tank for cooling and diluting the powder separated from the sedimentation tank using the stored cooling water. The method of claim 4, wherein
The cooling water is added to a volume of three times or more of the powder, the apparatus for producing a positive electrode active material using sedimentation, characterized in that to dilute the powder. The method of claim 4, wherein
Apparatus for producing a positive electrode active material using the sedimentation is installed on the rear end of the cooling tank further comprises a filter for filtering the powder. The method according to claim 6,
It is installed at the rear end of the filter apparatus for producing a positive electrode active material using sedimentation, characterized in that it further comprises a back pressure regulator for maintaining a constant pressure of the fluid. The method of claim 4, wherein
The cooling tank manufacturing apparatus of the positive electrode active material using the sedimentation, characterized in that the auxiliary cooling device for auxiliary cooling of the powder injected from the sedimentation tank is further installed. The method of claim 1,
The sedimentation tank is an apparatus for producing a positive electrode active material using sedimentation, characterized in that the flow rate of the reactant introduced therein is designed to be less than 4.6cm / s. 10. The method according to any one of claims 1 to 9,
The cathode active material is LiMPO ₄ of the olivine structure Apparatus for producing a positive electrode active material using sedimentation, characterized in that. A premixer for stirring the iron solution and the lithium solution introduced into different lines;
A main mixer in which the solution mixed in the premixer and the supercritical water are joined and stirred;
A heater, which heat-exchanges with the water before the supercritical state and makes the supercritical state;
A reactor for producing a positive electrode active material through a supercritical reaction of the mixture mixed in the main mixer;
A settling tank in which the reactants generated in the reactor are input and separated into hot water and powder by the settling action;
A cooling tank for cooling and diluting the powder separated from the sedimentation tank by using the stored cooling water; And
High temperature water separated from the sedimentation tank is introduced into the heat exchange, and the apparatus for producing a positive electrode active material using the sedimentation, characterized in that it comprises a heat exchanger is installed in the front of the heater to exchange heat with water before the supercritical state . The method of claim 11,
The line introduced into the sedimentation tank is an apparatus for manufacturing a positive electrode active material using sedimentation, characterized in that connected to the sedimentation tank inclined downward. The method of claim 11,
The cooling water is added to a volume of three times or more of the powder, the apparatus for producing a positive electrode active material using sedimentation, characterized in that to dilute the powder. The method of claim 11,
Apparatus for producing a positive electrode active material using the sedimentation is installed on the rear end of the cooling tank further comprises a filter for filtering the powder. 15. The method of claim 14,
It is installed at the rear end of the filter apparatus for producing a positive electrode active material using sedimentation, characterized in that it further comprises a back pressure regulator for maintaining a constant pressure of the fluid. The method of claim 11,
The cooling tank manufacturing apparatus of the positive electrode active material using the sedimentation, characterized in that the auxiliary cooling device for auxiliary cooling of the powder injected from the sedimentation tank is further installed. The method of claim 11,
The sedimentation tank is an apparatus for producing a positive electrode active material using sedimentation, characterized in that the flow rate of the reactant introduced therein is designed to be less than 4.6cm / s. 18. The method according to any one of claims 11 to 17,
The cathode active material is LiMPO ₄ of the olivine structure Apparatus for producing a positive electrode active material using sedimentation, characterized in that.

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