WO2008120938A1

WO2008120938A1 - A device for manufacturing rapidly solidified powder alloy including si precipitates of active material for rechargable li-battery and a method thereof

Info

Publication number: WO2008120938A1
Application number: PCT/KR2008/001795
Authority: WO
Inventors: Hyang-Yeon Kim; Jong-Goo Kang
Original assignee: Il Jin Electric Co., Ltd.
Priority date: 2007-03-30
Filing date: 2008-03-31
Publication date: 2008-10-09
Also published as: KR100912830B1; KR20080089024A

Abstract

Provided are an apparatus and a method for manufacturing rapidly solidified silicon based alloy powder that is used as a negative active material of a secondary lithium battery and has a fine grain structure where average grain size of silicon phase at 100 nm or lower in a matrix phase is uniformly dispersed and precipitated. The apparatus includes: a high speed ejection module which melts alloy powder including silicon and ejects the melted material at a high speed; a rotator which rotates relative to the high speed ejection module so as to quickly cool down the melted material ejected from the high speed ejection module by colliding the melted material with the rotator; and a chamber which includes the rotator and blocks airflow from the outside so as to prevent oxidation of particles of the alloy powder that collide with the rotator and scatter. The method includes: a high speed ejection operation which melts alloy powder including silicon and then ejects the melted material at a high speed; a cooling operation which quickly cools down the ejected melted material inside a chamber in which airflow with the air is blocked, by colliding the melted material with a rotator that rotates at a high speed.

Description

A DEVICE FOR MANUFACTURING RAPIDLY SOLIDIFIED POWDER ALLOY

INCLUDING SI PRECIPITATES OF ACTIVE MATERIAL FOR RECHARGABLE

LI-BATTERY AND A METHOD THEREOF

TECHNICAL FIELD

The present invention relates to a device and method for manufacturing rapidly solidified silicon based alloy powder used as a negative active material of a secondary lithium battery, and more particularly, to a device and method for manufacturing alloy powder having a microstructure where average grain size of silicon phase is uniformly distributed in a matrix phase at 100 iim or lower .

BACKGROUND ART

Generally, secondary batteries indicate batteries in which charge and discharge are repeated. Recently, as the use of mobile devices, such as mobile phones, lap tops, and portable multimedia players (PMPs), increases, from among such secondary batteries, secondary lithium batteries, which are light and have a high charge and discharge capacity, have come into the spotlight.

FIG. 1 is a conceptual diagram of a conventional secondary lithium battery 100.

As illustrated in FIG. 1 , in the conventional lithium battery 100, a negative electrode 101 and a positive electrode 102 are separately disposed inside a sealed case, a separation film 103 is interposed between the negative electrode 101 and the positive electrode 102, and an electrolyte 104 is filled in the remaining space of the sealed case. Lithium ions 105, included in the electrolyte 104, electrochemically react with the negative electrode 101 and the positive electrode 102 so as to generate current.

For such an electrochemical reaction, a lithium cobalt oxide is coated on the negative electrode 101 in a gel form, as an anode active material, and a carbon based cathode active material is coated on the positive electrode 102.

As mobile communication devices or mobile electronic devices develop, high efficiency energy storing media are required. In such an environment, high efficiency (high capacity and long durability) of a second lithium battery, which is expected to have the highest energy density, is being studied. The theoretical capacity of a carbon based negative active material of a currently commercialized second lithium battery is 372 mAh/g, however, in the future, this capacity will not fulfill a required performance of a high capacity secondary battery. Among the new anode materials, silicon alloy has been reported to be one of the most promising anode materials as it can substitute the commercial graphite because its much high theoretical capacity (Si:4000mAh/g). However, when silicon alloy reacts with lithium ions, large specific volume changes expands up to 300% of its initial volume, and thus an electrode ruptures. In order to solve such a problem, average grain size of the silicon phase should be uniformly and finely distributed on a matrix phase at 100 ran or lower, so that the matrix phase suppresses the volume expansion of the silicon phase. Also, the matrix phase should have high intensity and excellent electric conductivity.

Generally, examples of a method of manufacturing alloy powder include an atomization method, a melt-spinning method, a rotating electrode (RSR) method, a mechanical alloying method, and a chemical method.

However, since the silicon based alloy powder should have a fine grain structure as stated above, the mechanical alloying method or the chemical method cannot be used. Accordingly, in order to rapidly manufacture rapidly solidified silicon based alloy powder used as a nagative active material of the secondary lithium battery, the silicon based alloy power needs to be manufactured for rapid solidification.

FIGS. 2 and 3 are diagrams for describing apparatuses and methods for manufacturing conventional rapidly solidified metal powder;

FIG. 2 illustrates an atomizing method using gas. According to the atomizing method, an alloy is melted in a crucible 201 , and a nozzle 202 is opened so as to eject the melted alloy, where high speed gas 203 acts as a carrier. Thus, cooling rate is increased since a contact area of the melted alloy and air is maximized. The maximum cooling rate of such an atomizing method is approximately 10^{5 °}C/sec.

FIG. 3 illustrates an apparatus for manufacturing a rapidly solidified alloy using a melt spinning method. Referring to FIG. 3, a melted alloy 302 inside a crucible 301 is contacted with a rotating roller 303 so as to obtain high cooling rate. Such a melt spinning method is generally used to obtain an alloy having an amorphous strip form, and the cooling rate of the melt spinning method is approximately 10^{7 °}C/sec.

When silicon based alloy powder is manufactured by using a conventional rapid solidification method, several problems may occur. The cooling rate of the atomizing method of FIG. 2 is relatively low, and thus average grain size of silicon phase in a matrix phase are several hundreds nm. Also, since it is difficult to uniformly control the size of the final powder, it is difficult to maintain uniform cooling rate for ejected particles. In the case of manufacturing silicon based alloy powder by using the melt spinning method of FIG. 3, it is difficult to realize a critical cooling rate for having a fine grain structure. Such conventional methods are methods having a cooling speed of 10^{7 "}C /sec or lower, and thus are not suitable for average grain size of uniformly dispersing and precipitating silicon phase in a silicon based alloy at 100 ran or lower. Thus, a new apparatus and method for manufacturing powder are required.

A new apparatus for manufacturing silicon based alloy powder should guarantee a cooling rate of 10^{7 "}C /sec or more, and satisfy a condition of not oxidizing the surface of a particle. Also, a fine grain structure having alloy powder should be manufactured.

DETAILED DESCRIPTION OF THE INVENTION

TECHNICAL PROBLEM

The present invention provides an apparatus and method for manufacturing alloy powder for a secondary lithium battery, where average grain size of silicon phase is uniformly distributed in a matrix phase at 100 ran or lower.

TECHNICAL SOLUTION

According to an aspect of the present invention, there is provided an apparatus for manufacturing rapidly solidified silicon based alloy powder that is used as a negative active material of a secondary lithium battery and has a structure where average grain size of silicon phase at 100 nm or lower in a matrix phase are uniformly dispersed and precipitated, the apparatus comprising: a high speed ejection module which melts alloy powder including silicon and ejects the melted material at a high speed; a rotator which rotates relative to the high speed ejection module so as to quickly cool down the melted material ejected from the high speed ejection module by colliding the melted material with the rotator; and a chamber which includes the rotator and blocks airflow from the outside so as to prevent oxidation of particles of the alloy powder that collide with the rotator and scatter. According to another aspect of the present invention, there is provided a method of manufacturing rapidly solidified silicon based alloy powder that is used as a negative active material of a secondary lithium battery and has a fine grain structure where silicon phase at 100 nm or lower in a matrix phase is uniformly dispersed and precipitated, the method comprising: a high speed ejection operation which melts alloy powder including silicon and then ejects the melted material at a high speed; a cooling operation which quickly cools down the ejected melted material inside a chamber in which airflow with the air is blocked, by colliding the melted material with a rotator that rotates at a high speed.

The high speed ejection module may comprise a plasma thermal spray device.

When the high speed ejection module melts the alloy powder and ejects the melted material, argon gas may be used as a carrier of the melted material.

An ejection angle of the melted material that is quickly ejected from the high speed ejection module may be from 0° to less than 40°.

The ejection speed of the melted material may be 150 m/s or more.

The scattering speed of the particles of the alloy powder that collide with the rotator and scatter may be 40 m/s or more.

The initial working pressure of the chamber may be 1.3*10^"5 MPa or lower. The rotator may be any one of a copper plate, a copper plate coated with chrome, and an iron plate.

The rotator may be cooled down by liquid argon or liquid helium that is supplied from the outside of the chamber and is ejected to the rotator.

Argon gas or helium gas may be supplied to the inside the chamber from the outside of the chamber so as to suppress droplets from forming oxides and to increase a cooling effect of the droplets when the melted material collides with the rotator.

The rotator may have any one of a plate shape, a cone shape, a single roll shape, a twin roll shape, and a drum shape.

The high speed ejection operation may be performed via a plasma thermal spray method.

Argon gas may be used as a carrier of the melted material in the high speed ejection operation.

An ejection angle of the melted material ejected in the high speed ejection operation may be from 0° to less than 40°.

The ejection speed of the melted material in the high speed ejection operation may be 150 m/s or more.

The scattering speed of particles of the alloy powder that are scattered by colliding with the rotator in the cooling operation may be 40 m/s or more.

The initial working pressure of the chamber in the cooling operation may be 1.3^χ10^"5 MPa or lower.

The rotator may be any one of a cooper plate, a copper plate coated with chrome, and an iron plate. The rotator may be cooled down by liquid argon or liquid helium that is supplied from the outside of the chamber and ejected to the rotator.

Argon gas or helium gas may be supplied from the outside of the chamber to the inside the chamber so as to suppress droplets formed in the cooling operation from forming oxides and to increase a cooling effect of the droplets. The alloy powder in the high speed ejection operation may be an alloy comprising at least three components, where silicon is included 50 at% or more.

The size of the particles of the alloy powder supplied in the high speed ejection operation may be between 50 μm and 200 μm.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a conceptual diagram of a conventional secondary lithium battery; FIG. 2 is a diagram for describing an apparatus and method for manufacturing conventional rapidly solidified metal powder;

FIG. 3 is a diagram for describing another apparatus and method for manufacturing conventional rapidly solidified metal powder;

FIG. 4 is a diagram for describing an apparatus and method for manufacturing rapidly solidified silicon based alloy powder used as a negative active material of a secondary lithium battery, according to an embodiment of the present invention;

FIG. 5 is a diagram for describing an apparatus and method for manufacturing rapidly solidified silicon based alloy powder used as a negative active material of a secondary lithium battery, according to another embodiment of the present invention;

FIG. 6 is a diagram for describing an apparatus and method for manufacturing rapidly solidified silicon based alloy powder used as a negative active material of a secondary lithium battery, according to another embodiment of the present invention;

FIG. 7 is a diagram for describing an apparatus and method for manufacturing rapidly solidified silicon based alloy powder used as a negative active material of a secondary lithium battery, according to another embodiment of the present invention; FIG. 8 is a diagram for describing an apparatus and method for manufacturing rapidly solidified silicon based alloy powder used as a negative active material of a secondary lithium battery, according to another embodiment of the present invention;

FIG. 9 is a flowchart illustrating a method of manufacturing rapidly solidified silicon based alloy powder used as a negative active material of a secondary lithium battery, according to an embodiment of the present invention; and

FIG. 10 is a diagram for describing the distribution of silicon particles phase in a rapidly solidified silicon based negative active material used in a secondary lithium battery.

< Explanation of Reference numerals designating the Major Elements of the Drawings > 1Oa-IOb₁IOc₁IOd₁IOe...Apparatus for manufacturing silicon based alloy powder 20...High speed Ejection Module 30a,30b,30c,30d,30e... Rotator

40...Chamber 50...Rotary Motor

60...Vacuum Pump 70...Cooling Medium Supply Tube 80...Oxidation Blocking Gas Supply Tube θ... Ejection Angle

MODE OF THE INVENTION

Hereinafter, the present invention will be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown.

FIG. 4 is a diagram for describing an apparatus 10a and a method of manufacturing rapidly solidified silicon based alloy powder used as a negative active material of a secondary lithium battery, according to an embodiment of the present invention. Referring to FIG. 4, the apparatus 10a according to the current embodiment of the present invention includes a high speed ejection module 20, a rotator 30a, a chamber 40, a rotary motor 50, a vacuum pump 60, a cooling medium supply tube 70, and an oxidation blocking gas supply tube 80.

The high speed ejection module 20 uses a well known plasma thermal spray device. Thus, a detailed description about the principle and structure of the plasma thermal spray device is omitted herein. The high speed ejection module 20 receives silicon based alloy powder of which the size is approximately from 20 μm to 200 μm, instantly melts the silicon based alloy powder by using a super high voltage, and ejects the melted material to the outside of the high speed ejection module 20. The high speed ejection module 20 controls the ejection speed of the melted material by using argon gas as a carrier.

An ejection angle θ of the melted material ejected at a high speed from the high speed ejection module 20 may be between 0° to lower than 40°. As illustrated in FIG. 4, the ejection angle θ indicates an angle formed by the length direction of the high speed ejection module 20 and the ejection direction of the melted material. It is the most ideal when the ejection angle θ is 0°, and when the ejection angle θ is 40° or more, the melted material ejected from the high speed ejection module 20 may not collide with the rotator 30a that will be described later. In this case, the cooling speed may not be sufficiently high.

The ejection speed of the melted material may be 150 m/s or more. When the ejection speed is lower than 150 m/s, a cooling speed of 10^7°C/sec or more cannot be obtained.

The rotator 30a is spaced apart from the bottom of high speed ejection module 20, and is installed to rotate relatively to the high speed ejection module 20. The rotator 30a quickly cools down droplets generated when the melted material ejected from the high speed ejection module 20 collides with the rotator 30a at a high speed. The cooling speed of the melted material that collided with the rotator 30a increases with the speed of the rotator 30a. The scattering speed of particles of the alloy powder that are scattered by colliding with the rotator 30a may be 40 m/s or more. The scattering speed indicates a linear speed of the particle that proceeds perpendicular to a rotating direction of the rotator 30a after the particle collides with the rotator 30a that rotates at a high speed. When the scattering speed is lower than 40 m/s, the melted material is not sufficiently dispersed when collided with the rotator 30a, and thus the cooling speed cannot reach 10^{7 °}C /sec.

The rotator 30a may be any one of a copper (Cu) plate, a Cu plate coated with chrome (Cr), and an iron (Fe) plate. The rotator 30a may use a material having an excellent thermal conductivity. Also, the rotator 30a may have high strength since the melted material collides with the rotator 30a at a high speed. Thus considering the above properties, the rotator 30a is manufactured by using the above listed materials. In other words, the Cu plate has high thermal conductivity, Cr has a higher strength than Cu, and thus can suppress abrasion of the Cu plate due to collision of the melted material, and the Fe plate has relatively low thermal conductivity than the Cu plate but is cheap. The shape of the rotator 30a may vary, and the shape is a plate shape, in the current embodiment.

The chamber 40 is installed to include the rotator 3Oa₁ and is prepared to block airflow from the outside in order to prevent the particles of the alloy powder that is scattered after colliding with the rotator 30a from being oxidized. The chamber 40 is combined with the high speed ejection module 20. The initial working pressure of the chamber 40 may be 1.3x10⁵ MPa or lower so as to decrease the number of oxygen molecules inside the chamber 40 and prevent the surface of the particles cooled down in the chamber 40 from being oxidized.

The rotary motor 50 is prepared to rotate the rotator 30a. Since any well known motor can be used as the rotary motor 50, a detailed description about the structure of the rotary motor 50 is omitted herein. The rotary motor 50 is mechanically connected with the rotator 30a, and thus, when the rotary motor 50 rotates, the rotator 30a rotates. The vacuum pump 60 is prepared to decrease the number of oxygen molecules in the chamber 40 by sufficiently decreasing the initial working pressure of the chamber 40 to be lower than the air pressure. The vacuum pump 60 may use at least one of a conventional rotary pump or a diffusion pump. The vacuum pump 60 is only operated in the initial stage, and stops operating when a cooling medium that is described later is supplied.

The cooling medium supply tube 70 is connected with the chamber 40 and operates as a path for supplying the cooling medium from the outside of the chamber 40. The cooling medium supplied to the chamber 40 through the cooling medium supply tube 70 may be liquid argon (Ar) or liquid helium (He). The cooling medium supplied through the cooling medium supply tube 70 is ejected to the rotator 30a to effectively decrease the temperature of the rotator 30a.

The oxidation blocking gas supply tube 80 is connected with the chamber 40, and is prepared to effectively prevent the surface of the particles of the alloy powder, formed by colliding with the rotator 30a and quickly cooling down inside the chamber 40, from being oxidized. Oxidation blocking gas flowed in from the outside of the chamber 40 through the oxidation blocking gas supply tube 80 may be Ar gas or He gas.

FIG. 9 is a flowchart illustrating a method of manufacturing rapidly solidified silicon based alloy powder that is used as a negative active material of a secondary lithium battery and has a fine grain structure where average grain size of silicon phase at 100 ran or lower in a matrix phase is uniformly dispersed and precipitated, according to an embodiment of the present invention. The method using the apparatus 10a will now be described with reference to FIGS. 4 and 9, and with the operations of the apparatus 10a. First, the vacuum pump 60 is operated to decrease the internal pressure of the chamber 40 to be sufficiently low, for example, 1.3x10⁵ MPa or lower.

Then, the high speed ejection module 20 is charged with silicon based alloy powder. The size of the particles of the alloy powder supplied in a high speed ejection operation (operation S1 ) may be 200 μm or lower. When the size exceeds 200 μm, a problem may occur while the high speed ejection module 20 instantly melts the alloy powder, and the cooling speed decreases. Also, the size of the particles that are actually used may be between 50 μm and 200 μm.

The high speed ejection module 20, employing the plasma thermal spray method, is operated to perform the high speed ejection operation (operation S1 ), where a very small amount of alloy powder is instantly melted by applying high electric energy and the melted material thereof is ejected from the high speed ejection module 20 by using liquid argon as a carrier. The alloy powder supplied in the high speed ejection operation (operation S1 ) may be an alloy including at least three components, wherein 50 at% or more of silicon is included. If less than 50 at% silicon is included in the alloy, an electric characteristic as a negative active material of the secondary lithium battery may not show.

The ejection speed of the melted material may be controlled by adjusting the ejection speed of the liquid argon, i.e. the carrier. That is, the ejection speed of the melted material may be 150 m/s or more. The problems that may occur when the ejection speed is less than 150 m/s have been described above while describing the structure of the apparatus 10a, and thus the descriptions thereof are omitted. An ejection angle θ of the melted material ejected at a high speed in the high speed ejection operation (operation S1 ) may be from 0° to lower than 40°. The problems that may occur when the ejection angle θ is out of the above range have been described while describing the structure of the apparatus 10a, and thus the descriptions thereof are omitted.

At the same time, a cooling operation (operation S2) is performed, where the melted material ejected in the high speed ejection operation (operation S1 ) is quickly cooled down by colliding the melted material with the rotator 30a that rotates at a high speed inside the chamber 40 of which the pressure is lower than the air pressure. In the cooling operation (operation S2), the rotary motor 50 is operated to rotate the rotator 30a, which is mechanically connected with the rotary motor 50. The melted material ejected in the high speed ejection operation (operation S1 ) collides with the rotator 30a that rotates at a high speed due to the rotary motor 50, and is cooled down to the alloy powder having a minute particle size. The scattering speed of particles of the alloy powder that is scattered by being collided with the rotator 30a in the cooling operation (operation S2) may be 40 m/s or more. The problems that may occur when the scattering speed is lower than 40 m/s have been described above while describing the structure of the apparatus 10a, and thus the descriptions thereof are omitted.

Airflow between the inside and outside of the chamber 40 should be blocked in the cooling operation (operation S2). Also, the initial working pressure of the chamber 40 may be 1.3x10⁵ MPa or lower. The problems that may occur when the initial working pressure exceeds 1.3*10^~5 MPa, i.e., that the surface of the particles of the alloy powder formed in the cooling operation (operation S2) may be oxidized due to oxygen particles inside the chamber 40, have been described above while describing the structure of the apparatus 10a.

The rotator 30a in the cooling operation (operation S2) may be any one of a Cu plate, a Cu plate coated with Cr, and a Fe plate. The reason for using such materials has been described above while describing the structure of the apparatus 10a, and thus the description thereof is omitted. The rotator 30a can more effectively cool down the melted material by using liquid argon or liquid helium that is supplied from the outside of the chamber 40 and is ejected to the rotator 30a. Also, in order to prevent the particles of the alloy powder from being oxidized in the cooling operation (operation S2), argon gas or helium gas may be supplied to the chamber 40 from the outside of the chamber 40. As such, when a cooling medium, such as liquid argon or liquid helium, or oxidation blocking gas, such as argon gas or helium gas, is supplied, the vacuum pump 60 may stop operating. Here, the pressure of the chamber 40 may increase more than the air pressure, and in this case, an exhaust valve suitable for the chamber 40 may be installed so that the pressure of the chamber 40 does not extremely increase.

The shape of the rotator 30a in the cooling operation (operation S1 ) is a plate shape. FIG. 10 is a diagram for describing the distribution of silicon phase in a rapidly solidified silicon based negative active material used in a secondary lithium battery. FIG. 10 conceptually illustrates a micro-structure of the rapidly solidified silicon based alloy powder used as a negative active material of the secondary lithium battery manufactured by using the above apparatus 10a and method. Referring to FIG. 10, dark circles are precipitates of the silicon phase, and a white portion is a matrix phase. Silicon based alloy powder having the similar micro-structure as shown in FIG. 10 is obtained via an experiment under the following conditions. In the experiment, the high speed ejection module 20, employing the plasma thermal spray device, is used, the particles size of silicon based alloy powder supplied to the high speed ejection module 20 is 90 μm, an ejection angle θ of the melted material is 10°, the ejection speed is 150 m/s, the diameter of the rotator 30a is 200 mm, the rotating speed of the rotator 30a is 4000 rpm, and the linear speed of the particles that are scattered after colliding with the rotator 30a is 71.3 m/s. According to the embodiments of the present invention, the apparatus and method for manufacturing alloy powder having uniformly and finely distributed silicon phase under 10 inn in a matrix phase are provided.

FIG. 5 is a diagram for describing an apparatus 10b and a method of manufacturing rapidly solidified silicon based alloy powder used as a negative active material of a secondary lithium battery, according to another embodiment of the present invention. Referring to FIG. 5, the apparatus 10b is the same as the apparatus 10a of FIG. 4 except that the shape of the rotator 30b is a cone shape, and thus the detailed descriptions of the apparatus 10b are omitted herein.

FIG. 6 is a diagram for describing an apparatus 10c and a method of manufacturing rapidly solidified silicon based alloy powder used as a negative active material of a secondary lithium battery, according to another embodiment of the present invention. Referring to FIG. 6, the apparatus 10c is the same as the apparatus 10a of FIG. 4 except that the shape of the rotator 30c is a single roll shape, and thus the detailed descriptions of the apparatus 10c are omitted herein.

FIG. 7 is a diagram for describing an apparatus 10d and a method of manufacturing rapidly solidified silicon based alloy powder used as a negative active material of a secondary lithium battery, according to another embodiment of the present invention. Referring to FIG. 7, the apparatus 1Od is the same as the apparatus 10a of FIG. 4 except that the shape of the rotator 3Od is a twin roll shape, and thus the detailed descriptions of the apparatus 10d are omitted herein.

FIG. 8 is a diagram for describing an apparatus 10e and a method of manufacturing rapidly solidified silicon based alloy powder used as a negative active material of a secondary lithium battery, according to another embodiment of the present invention. Referring to FIG. 8, the apparatus 10e is the same as the apparatus 10a of FIG. 4 except that the shape of the rotator 3Oe is a drum shape, and thus the detailed descriptions of the apparatus 10e are omitted herein.

As described above, the apparatus and method for manufacturing rapidly solidified silicon based alloy powder used as a negative active material of a secondary lithium battery according to the present invention can be used to manufacture silicon based alloy powder of which the silicon phase in the matrix phase has a uniformly distributed average grain size of 100 nm. By using the apparatus and method, the silicon based powder, which has a bright prospect as an active material of a secondary lithium battery, can be generated in a large amount.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by one of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.

Claims

1. An apparatus for manufacturing rapidly solidified silicon based alloy powder that is used as a negative active material of a secondary lithium battery and has a structure where average grain size of silicon phase at 100 nni or lower in a matrix phase is uniformly dispersed and precipitated, the apparatus comprising: a high speed ejection module which melts alloy powder including silicon and ejects the melted material at a high speed; a rotator which rotates relative to the high speed ejection module so as to quickly cool down the melted material ejected from the high speed ejection module by colliding the melted material with the rotator; and a chamber which includes the rotator and blocks airflow from the outside so as to prevent oxidation of particles of the alloy powder that collide with the rotator and scatter.

2. The apparatus of claim 1 , wherein the high speed ejection module comprises a plasma thermal spray device.

3. The apparatus of claim 1 , wherein when the high speed ejection module melts the alloy powder and ejects the melted material, argon gas is used as a carrier of the melted material.

4. The apparatus of claim 1 , wherein an ejection angle of the melted material that is quickly ejected from the high speed ejection module is from 0° to less than 40°.

5. The apparatus of claim 1 , wherein the ejection speed of the melted material is 150 m/s or more.

6. The apparatus of claim 1 , wherein the scattering speed of the particles of the alloy powder that collide with the rotator and scatter is 40 m/s or more.

7. The apparatus of claim 1 , wherein the initial working pressure of the chamber is 1.3x10⁵ MPa or lower.

8. The apparatus of claim 1 , wherein the rotator is any one of a copper plate, a copper plate coated with chrome, and an iron plate.

9. The apparatus of claim 1 , wherein the rotator is cooled down by liquid argon or liquid helium that is supplied from the outside of the chamber and is ejected to the rotator.

10. The apparatus of claim 1 , wherein argon gas or helium gas is supplied to the inside the chamber from the outside of the chamber so as to suppress droplets from forming oxides and to increase a cooling effect of the droplets when the melted material collides with the rotator.

11. The apparatus of claim 1 , wherein the rotator has any one of a plate shape, a cone shape, a single roll shape, a twin roll shape, and a drum shape.

12. A method of manufacturing rapidly solidified silicon based alloy powder that is used as a negative active material of a secondary lithium battery and has a fine grain structure where average grain size of silicon phase at 100 urn or lower in a matrix phase is uniformly dispersed and precipitated, the method comprising: a high speed ejection operation which melts alloy powder including silicon and then ejects the melted material at a high speed; a cooling operation which quickly cools down the ejected melted material inside a chamber in which airflow with the air is blocked, by colliding the melted material with a rotator that rotates at a high speed.

13. The method of claim 12, wherein the high speed ejection operation is performed via a plasma thermal spray method.

14. The method of claim 12, wherein argon gas is used as a carrier of the melted material in the high speed ejection operation.

15. The method of claim 12, wherein an ejection angle of the melted material ejected in the high speed ejection operation is from 0° to less than 40°.

16. The method of claim 12, wherein the ejection speed of the melted material in the high speed ejection operation is 150 m/s or more.

17. The method of claim 12, wherein the scattering speed of particles of the alloy powder that are scattered by colliding with the rotator in the cooling operation is 40 m/s or more.

18. The method of claim 12, wherein the initial working pressure of the chamber in the cooling operation is 1.3x10⁵ MPa or lower.

19. The method of claim 12, wherein the rotator is any one of a cooper plate, a copper plate coated with chrome, and an iron plate.

20. The method of claim 12, wherein the rotator is cooled down by liquid argon or liquid helium that is supplied from the outside of the chamber and ejected to the rotator.

21. The method of claim 12, wherein argon gas or helium gas is supplied from the outside of the chamber to the inside the chamber so as to suppress droplets formed in the cooling operation from forming oxides and to increase a cooling effect of the droplets.

22. The method of claim 12, wherein the rotator has any one of a plate shape, a cone shape, a single roll shape, a twin roll shape, and a drum shape.

23. The method of claim 12, wherein the alloy powder in the high speed ejection operation is an alloy comprising at least three components, where silicon is included 50 at% or more.

24. The method of claim 13, wherein the size of the particles of the alloy powder supplied in the high speed ejection operation is between 50 μm and 200 μm.