KR102581658B1 - The positive electrode active materical recovery unit and a recovery method using the same - Google Patents

Abstract

The present invention provides a cathode active material recovery device and a recovery method using the same, comprising: a rotating mesh unit made of a cylindrical mesh with one end open so that a cathode containing an oxide-based cathode active material is introduced therein; a heating furnace in which the rotating mesh unit is disposed to heat the rotating mesh unit; The technical gist is that it includes a rotation means disposed outside the heating furnace, extending through the heating furnace, coupled to the rotating mesh unit, and having a rotating shaft for rotating the rotating mesh unit. As a result, the positive electrode active material can be easily recovered from the positive electrode in its original shape through a dry method under an oxidizing atmosphere, and the obtained positive active material can be applied to manufacturing a positive electrode for a lithium secondary battery.

Description

Positive electrode active material recovery unit and a recovery method using the same}

The present invention relates to an oxide-based cathode active material recovery device and a recovery method using the same. More specifically, the cathode active material can be easily recovered from the cathode in its original shape through a dry method under an oxidizing atmosphere, and the obtained cathode active material can be converted to lithium lithium as is. It relates to a cathode active material recovery device applicable to manufacturing cathodes for secondary batteries and a recovery method using the same.

Lithium secondary batteries are secondary batteries with excellent performance such as high capacity, high output, and long lifespan, and are widely used in small electronic products such as electronic devices, portable computers, and mobile phones. In particular, as interest in green growth and new and renewable energy has recently focused, the demand for large-capacity lithium secondary batteries is expected to increase rapidly as electric vehicles are commercialized. Although the lithium secondary battery market and industry are expected to grow rapidly, lithium (Li), an essential metal for cathode active materials, and related compounds are not available in Korea, so they are entirely imported and used from overseas. Therefore, in countries without natural resources, it is necessary to recover and recycle cathode scrap generated during the lithium secondary battery manufacturing process or lithium secondary battery cathode active material discarded after use.

Conventional technologies for extracting or recovering various metals or compounds such as lithium from the positive electrode of a lithium secondary battery include 'Korea Intellectual Property Office Patent No. 10-0832900 Lithium Battery Processing Method' and 'Korea Intellectual Property Office Patent No. 10-1244632'. As in 'Method for recovering organic metals from portable devices', the positive electrode separated from the waste lithium secondary battery is dissolved in hydrochloric acid, sulfuric acid, nitric acid, or oxalic acid and then neutralized with alkali. A process was used to recover cobalt (Co), nickel (Ni) by precipitating them as hydroxides, or a method of separating metals such as cobalt, manganese, and nickel from the anode solution using a solvent extraction method was used. These prior technologies were mainly aimed at recovering cobalt and nickel, and because lithium is cheaper than cobalt and nickel, recovery was not performed separately. However, lithium resources are very limited, and large-capacity lithium secondary batteries for electric vehicles are likely to use phosphorite-based LiFePO ₄ , which does not contain cobalt or nickel, as a cathode active material, so there will be greater interest in recovering or recycling lithium and related compounds in the future. It seems to be concentrated.

Most conventional treatment methods for recovering oxide-based positive electrode active materials involve dissolving the positive electrode in a strongly acidic solution and then separating and recovering expensive metals such as lithium, cobalt, and nickel in the dissolved solution. Therefore, each metal is first separated from the other. Not only is the process cost for high-purity separation expensive, but strong acids must be used when dissolving the anode, leading to serious problems such as serious environmental pollution due to evaporation into the atmosphere and, in particular, corrosion of facilities due to the acid. In addition, when recovering phosphate-based positive electrode active material under an oxidizing gas atmosphere, taking phosphate (LiFePO ₄ ) as an example, by-products such as Fe ₂ P ₂ O ₇ are generated in addition to the desired FePO ₄ , and when recovered under an inert gas atmosphere, the binder is not properly carbonized. Therefore, there is a problem in that the separation of the positive electrode active material and the binder is not performed properly, and as a result, recovery of the positive electrode active material is not easy.

Korea Intellectual Property Office Patent No. 10-0832900 Korea Intellectual Property Office Registered Patent No. 10-1244632 Korea Intellectual Property Office Patent No. 10-1294335 Korea Intellectual Property Office Registered Patent No. 10-1392616

Therefore, the object of the present invention is to easily recover the oxide-based positive electrode active material in its original shape from the positive electrode through a dry method under an oxidizing atmosphere, and to provide a positive electrode active material recovery device that can be applied to manufacture a positive electrode for a lithium secondary battery using the obtained positive electrode active material as is. The purpose is to provide a recovery method using this.

The cathode active material recovery device of the present invention for achieving the above object includes a cylindrical rotating mesh part with one side open so that a cathode containing an oxide-based cathode active material is introduced therein; a heating furnace in which the rotating mesh part is accommodated and that heats the rotating mesh part; Rotation means fixed to one side of the heating furnace and having a rotating shaft that penetrates the heating furnace and is coupled to the rotating mesh unit to rotate the rotating mesh unit by driving it; It includes a gas supply unit connected to the heating furnace and supplying a gas containing oxygen into the interior of the heating furnace, wherein the rotating mesh unit extends horizontally in the horizontal direction and has a cylindrical shape with both sides open in the extension direction. , a mesh body whose peripheral surface is formed into a mesh structure; A pair of mesh coupling parts coupled to both ends of the mesh body in the extension direction and formed in a ring shape corresponding to the shape of the end of the mesh body so as to surround the end of the mesh body; It is formed in a bar shape extending along the extension direction of the mesh body, both ends are coupled to the pair of mesh coupling parts, and are spaced apart from each other along the perimeter of the mesh body to support the perimeter of the mesh body. and a plurality of mesh supports; wherein one of the pair of mesh coupling portions is provided with a rotation axis support portion to which the rotation axis of the rotation means is coupled at the center and shields the inner opening of the mesh coupling portion, and the pair of mesh coupling portions includes a plurality of mesh support portions; In another one of the mesh coupling portions, an inlet through which the positive electrode is introduced into the interior of the mesh body is formed, and a step protrudes from the peripheral end of the mesh coupling portion toward the center of the inlet to shield the edge of the inner opening of the mesh coupling portion. This is formed to prevent the anode inside the mesh body from leaking out through the inlet when the mesh body rotates.
And, the mesh body is characterized by being made of 20 to 100 mesh.

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The cathode active material recovery method of the present invention for achieving the above object includes preparing a cathode and a cathode active material recovery device according to the above; Injecting the positive electrode into the rotating mesh unit; supplying a gas containing oxygen to the heating furnace and rotating and heating the rotating mesh unit to carbonize the binder contained in the anode; and rotating the rotating mesh unit to discharge the positive electrode active material separated from the positive electrode by carbonization of the binder to the outside.
And, after the step of discharging the cathode active material to the outside, it is characterized in that it includes the step of collecting the discharged cathode active material.
And, the temperature at which the rotating mesh unit is heated is characterized in that it is 400 to 600°C.
In addition, the positive electrode is characterized in that it is a positive electrode recovered from a waste battery or a positive electrode scrap left after cutting the positive electrode.
In addition, the positive electrode active material is characterized in that it is selected from the group consisting of lithium (Li), nickel (Ni), cobalt (Co), manganese (Mn), aluminum (Al), and mixtures thereof.

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According to the configuration of the present invention described above, the oxide-based positive electrode active material can be easily recovered from the positive electrode in its original shape through a dry method under an oxidizing atmosphere, and an effect applicable to manufacturing a positive electrode for a lithium secondary battery can be obtained using the obtained positive electrode active material as is. You can.

1 is a front view of a cathode active material recovery device according to an embodiment of the present invention;
Figure 2 is a perspective view of the rotating mesh unit,
Figure 3 is a flow chart of the cathode active material recovery method.

Hereinafter, the cathode active material recovery device 10 and the recovery method using the same according to the present invention will be described with reference to the drawings.

As shown in FIGS. 1 and 2, the cathode active material recovery device 10 includes a rotating mesh unit 100 made of a cylindrical mesh, a heating furnace 300 for heating the rotating mesh unit 100, and , and includes a rotation means 500 for rotating the rotation mesh unit 100.

The rotating mesh unit 100 is made of a cylindrical shape with one end open so that the positive electrode containing the positive electrode active material is introduced into the inside. The rotating mesh unit 100 consists of a mesh body 110 and a mesh coupling unit 130. , it further includes a rotation axis support part 150 and a mesh support part 170. The mesh body 110 is formed into a tube shape by rolling a plate-shaped mesh so that both sides are in contact with each other, and both ends are open. Here, the mesh body 110 is made of 20 to 100 mesh. If the mesh is less than 20 mesh, the positive electrode active material cannot properly escape to the outside and most of it remains in the rotating mesh part 100, and if it exceeds 100 mesh, not only the positive electrode active material but also the positive electrode active material is used. Conductive metal thin plate particles that must be separated from the battery are also discharged to the outside and mixed with the positive electrode active material. Therefore, the mesh body 110 is preferably made of 20 to 100 mesh. Additionally, the rotating mesh unit 110 is preferably cylindrical, but may be cylindrical with a polygonal cross-section depending on the design.

The mesh coupling portion 130 is formed in a ring shape at both ends of the mesh body 110 and is coupled to the mesh body 110 so that the mesh body 110 maintains its shape. Since the mesh body 110 is made of a material that is not hard, it is difficult to maintain its shape even if it is formed into a tubular shape. Therefore, a pair of mesh coupling parts 130 made of a material with high hardness are coupled to both ends so that the mesh body 110 maintains its tubular shape. One of these mesh coupling parts 130 serves as an anode inlet to enable the anode to be introduced.

One of the mesh coupling portions 130 is open to allow the anode to be introduced, and the other is blocked by the rotation axis support portion 150. The rotation shaft support portion 150 blocks access to the inside of the mesh body 110 from the outside, and the mesh coupling portion 130 so that the rotation shaft 510 connecting the rotation means 500 and the rotation mesh portion 100 is supported. formed in one of the This rotation shaft support portion 150 may block only a portion of the mesh coupling portion 130, but blocks the entire area of the mesh coupling portion 130 to prevent the anode disposed inside from being thrown outward by the rotation of the rotating mesh portion 100. It is desirable to do so.

A plurality of mesh supports 170 are coupled to the mesh coupling portion 130 to support the mesh body 110. The mesh support portion 170 prevents the mesh body 110 from sagging due to its own weight or the weight of the anode disposed therein. This mesh support portion 170 is formed in a bar shape along the longitudinal direction of the mesh body 110, and both ends are coupled with a pair of mesh coupling portions 130 to support the mesh body 110. The mesh support portion 170 is preferably made of a material with high hardness so as to firmly support the mesh body 110.

Among the cathode active material recovery devices 10, the heating furnace 300 has a rotating mesh unit 100 disposed therein and serves to heat the rotating mesh unit 100. The heating furnace 300 may be closed to block heat transfer to the outside, but an open heating furnace may be used depending on the design of the rotating mesh unit 100.

The rotating means 500 for rotating the rotating mesh unit 100 is disposed outside the heating furnace 300 and is connected to the rotating mesh unit 100 through the rotating shaft 510. The rotating shaft 510 extends through the heating furnace 300 and serves to connect the rotating mesh unit 100 disposed inside the heating furnace 300 and the rotating means 500 disposed outside the heating furnace. Accordingly, when the rotating shaft 510 is rotated by the rotating means 500, the rotating mesh unit 100 connected to the rotating shaft 510 is rotated inside the heating furnace 300 to recover the positive electrode active material. Here, the rotation means 500 is preferably a motor, which is generally the most used, but other means may be used.

A gas supply unit 700 that supplies gas into the heating furnace 300 is installed outside the heating furnace 300. When recovering the positive electrode active material, in the process of carbonizing the binder by heating, a gas containing oxygen is supplied into the heating furnace 300 through the gas supply unit 700 to synthesize carbon dioxide in the binder and remove it. In some cases, the gas supply unit 300 may further include a separate valve to adjust the supply amount of gas.

As a method of recovering the positive electrode active material, as shown in FIG. 3, first prepare the positive electrode and the positive electrode active material recovery device 10 (S1).

The positive electrode is a structure in which a positive electrode active material layer is formed on a thin conductive metal plate, and the conductive metal plate is a thin plate that functions as a current collector. Here, the conductive metal thin plate is not specifically limited, but the most commonly used aluminum (Al) thin plate is most preferable. The cathode active material layer is a layer in which the cathode active material is mixed with a binder. The binder binds the cathode active material particles together to maintain its shape, and the binder combines the cathode active material and the conductive metal sheet. Here, the positive electrode active material is preferably selected from the group consisting of lithium (Li), nickel (Ni), cobalt (Co), manganese (Mn), aluminum (Al), and mixtures thereof, and more specifically, LiCoO ₂ , Li ( Ni _x Mn _y Co _z )O ₂ , LiMnO ₂ and mixtures thereof are preferably selected from the group, but are not limited thereto.

The positive electrode for lithium secondary batteries uses positive electrode scraps left after cutting to a specific size to form positive electrodes or positive electrodes recovered from waste batteries, and the oxide-based positive electrode active material contained in the positive electrode or positive electrode scraps is used. Recovery is the purpose of the present invention.

The cathode active material recovery device 10 uses a device consisting of a rotating mesh unit 100, a heating furnace 300, and a rotating means 500 according to the present invention.

The positive electrode is introduced into the rotating mesh unit 100 (S2).

In order to separate the positive electrode active material from the positive electrode, which is a positive electrode or positive electrode scrap, the positive electrode is put into the rotating mesh unit 100 of the positive electrode active material recovery device. In the case of the rotating mesh unit 100, since it consists of a mesh body 110 of 20 to 100 mesh, the positive electrode active material with small particle size among the positive electrodes is discharged to the outside, and the conductive metal thin plate with large particles among the positive electrodes and prone to agglomeration is discharged to the rotating mesh unit ( 100).

The binder is carbonized by rotating and heating the rotating mesh unit 100 (S3).

The binder contained in the anode is carbonized by heating while rotating the rotating mesh unit 100 in which the anode is disposed. The rotary mesh unit 100 is heated by raising the temperature of the heating furnace 300. As the temperature increases, the binder contained in the positive electrode is carbonized, and the positive electrode active material particles bound to each other by the binder are separated from the binder. At this time, the rotating mesh unit 100 is heated and the rotating mesh unit 100 is continuously rotated. As the rotating mesh unit 100 rotates, the anode moves around within the rotating mesh unit 100 and is evenly heated and rotated. As the mesh portion 100 and the positive electrode collide with each other, the positive electrode active material is separated from the positive electrode due to the impact. If heated while the rotating mesh unit 100 is stationary and does not rotate, it is difficult for the positive electrode active material to separate from the positive electrode.

The temperature for heating the rotating mesh unit 100 is preferably 400 to 600°C. If the temperature is less than 400°C, some binders may not be carbonized depending on the type of binder, and if it exceeds 600°C, the temperature may be higher. This not only damages the cathode active material but also reduces economic feasibility.

The rotation speed of the rotating mesh unit 100 is preferably 10 to 120 rpm. If the rotation speed is less than 10 rpm, the positive electrode active material is not discharged to the outside of the rotating mesh unit 100 and is likely to remain inside the rotating mesh unit 100. If the rotation speed exceeds 120 rpm, the positive electrode in the rotating mesh unit 100 is exposed to the outside. It can bounce off.

In the process of carbonizing the binder, it is preferable that gas containing oxygen is supplied to the heating furnace 300 to carry out carbonization in an oxidizing atmosphere. It is preferable to use air or oxygen gas (O ₂ ) composed entirely of oxygen as the gas containing oxygen, but other than this, a gas mixed with oxygen and an inert gas may be used. When carbonizing a binder in an oxidizing atmosphere, carbon (C) from the binder is carbonized and oxygen (O) from the oxidizing atmosphere combine to produce carbon dioxide (CO ₂ ), which is discharged to the outside as a gas. Therefore, the binder is emitted as carbon dioxide and carbonized binder residue almost disappears, making it easier to separate the positive electrode active material from the binder. In contrast, in the conventional case, the binder is carbonized in an inert or reducing atmosphere. In this case, the binder is not carbonized into carbon dioxide but remains mixed with the positive electrode active material as carbon particles, making it difficult to remove from the surface of the positive electrode active material. Therefore, it is cumbersome to manufacture because it requires a separate washing process or oxidation process.

The rotating mesh unit 100 is rotated to discharge the positive electrode active material to the outside (S4).

The rotating mesh unit 100 is rotated to discharge the positive electrode active material separated from the positive electrode by carbonization of the binder in step S3 to the outside of the rotating mesh unit 100. When the rotating mesh unit 100 is not rotated, only a portion of the positive electrode active material in the rotating mesh unit 100 is discharged to the outside and most of the positive electrode active material remains in the rotating mesh unit 100. Additionally, in order for the conductive metal thin plates to come into contact with each other to enable aggregation, the rotating mesh unit 100 must be continuously rotated. That is, through the rotation of the rotating mesh unit 100, the positive electrode active material having a diameter smaller than the mseh diameter of the mesh body 100 is discharged to the outside, and the conductive metal thin plates with a large diameter that are clustered together remain in the rotating mesh unit 100. As a result, the conductive metal thin plate and the positive electrode active material are easily separated. The cathode active material discharged to the outside of the rotating mesh unit 100 is collected in the tray 310 disposed at the bottom of the heating furnace 300, and a step of collecting the cathode active material through this may be further included.

The oxide-based cathode active material obtained in this way uses a dry method of heating the cathode itself, unlike the wet method of making the cathode active material into a precursor, precipitating it, and then dissolving it in acid as in the conventional technology, and through this, the cathode active material is made into a precursor. It can be obtained with its size and shape maintained. In other words, since the positive electrode active material that has already been used as a positive electrode or has been manufactured in the best condition for use as a positive electrode is recovered in its original shape, it can be used immediately without the need for a separate process such as grinding. That is, the positive electrode active material recovered through the present invention can be mixed with lithium and a binder and then applied to a conductive metal thin plate to manufacture the recovered positive electrode active material as a positive electrode for a lithium secondary battery. Therefore, there is an advantage that the manufacturing efficiency of lithium secondary batteries increases as the process becomes much simpler than before.

10: Cathode active material recovery device 100: Rotating mesh unit
110: mesh body 130: mesh joint
150: Rotation axis support 170: Mesh support
300: heating furnace 310: tray
500: Rotation means 510: Rotation shaft
700: Gas supply unit

Claims (12)

A cylindrical rotating mesh part with one side open so that a positive electrode containing an oxide-based positive electrode active material is introduced therein;
a heating furnace in which the rotating mesh part is accommodated and that heats the rotating mesh part;
Rotation means fixed to one side of the heating furnace and having a rotating shaft that penetrates the heating furnace and is coupled to the rotating mesh unit to rotate the rotating mesh unit by driving it;
It includes a gas supply unit connected to the heating furnace and supplying gas containing oxygen into the heating furnace,
The rotating mesh unit,
A mesh body that extends horizontally in the transverse direction, has a cylindrical shape with both sides open in the extension direction, and has a mesh structure on the peripheral surface;
A pair of mesh coupling parts coupled to both ends of the mesh body in the extension direction and formed in a ring shape corresponding to the shape of the end of the mesh body so as to surround the end of the mesh body;
It is formed in a bar shape extending along the extension direction of the mesh body, both ends are coupled to the pair of mesh coupling parts, and are spaced apart from each other along the perimeter of the mesh body to support the perimeter of the mesh body. It includes a plurality of mesh supports,
In any one of the pair of mesh joints,
A rotating shaft support portion to which the rotating shaft of the rotating means is coupled is provided at the center, which shields the inner opening of the mesh coupling portion,
In the other of the pair of mesh joints,
An inlet through which the positive electrode is introduced into the mesh body is formed, and a step protruding toward the center of the inlet is formed at the peripheral end of the mesh coupling portion to shield the edge of the inner opening of the mesh coupling portion, so that the mesh coupling portion rotates. A positive electrode active material recovery device, characterized in that the positive electrode inside the mesh body is prevented from leaking through the inlet. According to clause 1,
A cathode active material recovery device, characterized in that the mesh body is made of 20 to 100 mesh. delete delete delete delete In the cathode active material recovery method,
Preparing a positive electrode and a positive electrode active material recovery device according to any one of claims 1 to 2;
Injecting the positive electrode into the rotating mesh unit;
supplying a gas containing oxygen to the heating furnace and rotating and heating the rotating mesh unit to carbonize the binder contained in the anode;
A cathode active material recovery method comprising rotating the rotating mesh unit to discharge the cathode active material separated from the cathode by carbonization of the binder to the outside. delete According to clause 7,
After discharging the positive electrode active material to the outside,
A cathode active material recovery method comprising the step of collecting the discharged cathode active material. According to clause 7,
A cathode active material recovery method, characterized in that the temperature for heating the rotating mesh unit is 400 to 600 ° C. According to clause 7,
A cathode active material recovery method, wherein the cathode is a cathode electrode recovered from a spent battery or a cathode scrap left after cutting the cathode. According to clause 7,
A cathode active material recovery method, wherein the cathode active material is selected from the group consisting of lithium (Li), nickel (Ni), cobalt (Co), manganese (Mn), aluminum (Al), and mixtures thereof.

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