KR101991691B1 - SAGGER FOR CALCINATION OF Li SECONDARY BATTERY ACTIVE MATERIAL AND METHOD FOR PREPARING THE Li SECONDARY BATTERY ACTIVE MATERIAL USING THE SAME - Google Patents

Abstract

The present invention relates to an inner shell for firing a secondary battery cathode active material and a method for manufacturing a secondary battery active material using the same, the inner shell for supporting a fired material for firing a cathode active material or an anode active material of a secondary battery, Wherein the inner wall of the inner wall has at least one or more through holes for the distribution of gas on the bottom surface or the bottom surface and the wall surface of the inner wall of the sintering furnace, A step of firing the firing furnace in an oxygen-containing gas atmosphere or an inert gas atmosphere, and a step of cooling and pulverizing the fired raw material in the firing furnace after firing from the firing furnace to obtain a secondary battery active material And a manufacturing method thereof.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a lithium secondary battery active material firing cloth, and a method for manufacturing active material using the same. BACKGROUND OF THE INVENTION 1. Field of the Invention [0002]

The present invention relates to an inner shell for firing a cathode active material for a secondary battery and a method for manufacturing an active material using the inner shell.

Lithium secondary batteries have high energy density, excellent output characteristics and light weight, and are widely used as energy storage devices for mobile communication devices, hybrid electric vehicles, and household appliances.

The core material of the lithium secondary battery is divided into an anode, a cathode, an electrolyte, and a separator. Current cathode materials for the lithium secondary battery include LiCoO2 or a cathode active material of the NCM (Nickel Cobal Manganese) series. Such a cathode active material is produced by putting a raw material containing a compound and a transition metal compound into a sagger as a sintering vessel and firing at a temperature in a range of 400 to 1100 ° C according to the type of the raw material to produce a cathode active material such as a lithium composite oxide can do.

In the firing process in the process of producing the cathode active material of the lithium secondary battery, firing is generally performed in an atmosphere of air containing oxygen. The firing atmosphere gas containing oxygen such as oxygen and air supplied from the outside can be easily The firing efficiency can be improved by contacting oxygen with the raw material carried in the frying pan.

In particular, since carbon dioxide is heavier than oxygen and air used for controlling the firing atmosphere, the carbon dioxide is left in the inner chamber and then, during the cooling process, And reacts with the lithium oxide on the surface of the active material to form lithium carbonate.

If the concentration of lithium carbonate is increased, the dispersibility of the slurry in the coating process of the cathode active material is lowered or the capacity of the battery is decreased. Therefore, it is necessary that the sintering process of the cathode active material smoothly discharges carbon dioxide generated during the process in the inner shell.

An object of the present invention is to provide an inner shell having a structure capable of facilitating the discharge of carbon dioxide generated when a cathode active material for a secondary battery or the like is fired, and a method for manufacturing an active material using the inner shell.

The present invention relates to an inner shell used for firing an active material for a secondary battery, the inner shell for carrying a fired material for firing a cathode active material or an anode active material of a secondary battery, And at least one through-hole for gas distribution is provided.

The inner shell may have a through hole on the wall surface, and the through hole on the wall surface is preferably located at a half of the height of the inner shell from the bottom surface.

The diameter of the through hole formed in the inner shell is preferably smaller than the size of the fleece material. For example, the diameter of the through hole may be 1 to 50 mm.

The through hole may have a circular shape, an elliptical shape, a polygonal shape, or a combination of two or more thereof.

The total area of the through-holes formed in the bottom surface of the inner fire wall can be in the range of 0.1 to 20% with respect to the total area of the bottom surface.

The inner shell includes a group consisting of mullite (3Al ₂ O ₃ 2SiO ₂ ), cordierite ((Mg, Fe ^{+ 3} ) ₂ Al ₄ Si ₅ O ₁₈ ), spinel (MgAl ₂ O ₄ ) and zircon (ZrSiO ₄ ) And at least one material selected from the above.

The inner fire wall may be provided with a lid which covers the opened upper surface, the upper surface of which is open for inflow and outflow of the object to be cleaned.

According to another aspect of the present invention, there is provided a method of manufacturing an active material, comprising the steps of: placing a raw material in an inner wall of the above-described inner wall and disposing an inner wall having a refractory material therein; A step of firing in a gaseous atmosphere or an inert gas atmosphere, and a step of removing the fired raw material from the firing furnace after cooling and pulverizing the fired raw material to obtain a secondary battery active material.

At this time, the raw material may be one in which the size of the raw material to be loaded on the inner wall is increased by molding the powder.

In addition, two or more fire resistant paints may be placed in the firing furnace and fired, and two or more fire resistant paints may be stacked in two or more layers to be fired.

Since the inner shell of the present invention includes the through hole at the bottom or the bottom surface and the bottom of the shell, carbon dioxide, which is a reaction by-product in the cathode active material sintering process, can be smoothly discharged from the inner shell.

Such a smooth discharge of carbon dioxide can lower the residual lithium concentration of the cathode active material, thereby improving the dispersibility of the cathode active material slurry and further improving the capacity of the battery.

In addition, by using the inventive inner shell, it is possible to increase the number of inner shells arranged in one firing furnace, and thus to produce a larger amount of active material.

FIG. 1 is a perspective view illustrating an example of an inner shell for firing a secondary battery active material provided in the present invention, in which a through hole is formed in a bottom surface.
FIG. 2 is a perspective view illustrating an example of an inner shell for firing secondary battery active material provided in the present invention, in which through holes are formed on a bottom surface and a wall surface.

It is an object of the present invention to provide an inner fire wall having a structure in which an atmospheric gas can flow smoothly from the outside into the interior of a firecracker and carbon dioxide or the like, a by-product generated in the firing process, will be.

Generally, a cathode active material of a secondary battery is manufactured by firing a raw material in a high-temperature firing furnace. In this case, the raw material is loaded on the firing furnace and put into the firing furnace. At this time, in order to obtain a uniform quality cathode active material by firing, it is required that the atmospheric gas can be smoothly introduced into the inner shell and that the carbon dioxide can be discharged into the inner shell without being remained.

To this end, the present invention provides an inner fire wall in which a through hole is formed.

In the case of firing using an inner fire wall having no through holes as in the present invention, the atmospheric gas flows through the upper face of the inner fire wall, And it is difficult to obtain a uniform firing quality because the contact probability is relatively small with respect to the raw material located at a deeper part such as the bottom surface of the inner fire wall.

Since the through-holes are formed in the inner shell, the atmospheric gas is supplied into the inner shell through the through-holes, so that the atmospheric gas can be uniformly supplied to the raw material of the cathode active material loaded in the inner shell, Can be achieved.

Such a through hole may be formed on the bottom surface of the inner fire wall as shown in FIG. 1, or may be formed on the bottom and wall surfaces of the inner fire wall as shown in FIG. The atmospheric gas of the firing furnace, in particular oxygen, flows into the interior of the firebox and is uniformly brought into contact with the raw material loaded in the firebox while rising to the top of the firebox by the through holes formed in the bottom surface of the interior fireplaces, Can be prepared.

On the other hand, when a through hole is included in the wall surface of the inner fire wall, the atmospheric gas can be introduced into the inner wall of the inner fire wall even in the flow of the atmospheric gas flowing to the side of the inner fire wall.

As described above, the through holes facilitate the flow of the atmospheric gas into the interior of the fire wall, as well as by-products such as carbon dioxide and water vapor generated during firing can be smoothly discharged from the interior wall.

If carbon dioxide remains in the sintered body, the lithium oxide and lithium carbonate on the surface of the cathode active material are formed during the cooling process after the sintering, which may cause a problem that the dispersibility of the slurry in the coating process of the cathode active material decreases or the capacity of the battery decreases have. However, in the case of having the through hole in the bottom surface or the side wall of the inner fire wall as in the present invention, the gas flow due to the inflow of the atmospheric gas through the through hole may occur, thereby suppressing the concentration of carbon dioxide or water vapor in the bottom of the fire wall have.

The through-holes of the inner protective layer are not particularly limited, but their shortest diameter is smaller than the size of the raw material for producing active material, which is a fumed material, in view of suppressing the flow of the raw material through the through holes.

On the other hand, in case of using an inner fire wall in which such through holes are formed, the raw material may be molded into a size having a predetermined particle size and then fired in an inner fire wall to be fired. As a result, the outflow to the through hole can be suppressed, and the flow of the atmospheric gas can be made more smooth because the space between the raw materials is large.

Since the through holes formed in the inner shell can be adjusted according to the size of the size of the fleece material loaded in the inner shell and the particle size of the fleece material loaded in the inner shell can be adjusted according to the size of the through hole, The size of the hole is not particularly limited. However, since it is preferable that oxygen, air, carbon dioxide, water vapor and the like can easily enter and exit, the through hole is preferably 1 mm or more, and as the size of the through hole decreases, the mechanical strength of the interior wall decreases. desirable.

On the other hand, the through-holes formed in the side wall of the inner fire wall may be formed at the front side of the side wall, but they are formed to a half of the height of the side wall from the bottom of the inner fire wall, A sufficient effect can be obtained for the inflow of the atmospheric gas and the discharge of reaction by-products. Of course, in the case where the through holes are formed up to the upper portion of the side wall, the atmospheric gas can flow into the inner shell more smoothly, and the firing efficiency of the raw material can be further improved.

The shape of the through hole formed in the bottom or wall surface of the inner protective cap is not particularly limited. For example, the through holes may be circular, elliptical, polygonal, or the like, or a combination of two or more of these shapes may be combined. Furthermore, any shape that is not defined by such a shape and has a shape of a regular or irregular shape may be used as long as it can flow the atmospheric gas and discharge the reaction by-products.

In the present invention, it is preferable that the through-holes formed on the bottom surface of the inner fire wall are formed in a range occupying an area of 0.1 to 20% with respect to the total area of the bottom surface. If it is formed to be less than 0.1% by area, the inflow of atmospheric gas such as air or oxygen or the discharge of carbon dioxide or water vapor is not smooth and the effect due to the formation of the through hole may not be sufficient. The strength is lowered and the probability of breaking the inner wall during the sintering process in the RHK (roller hearth kiln) may be increased.

Such an inner shell is not particularly limited, but may be selected from mullite (3Al ₂ O ₃ 2SiO ₂ ), cordierite ((Mg, Fe ^{+ 3} ) ₂ Al ₄ Si ₅ O ₁₈ ), spinel (MgAl ₂ O ₄ ), zircon ₄ ), and the like, or a combination of two or more thereof.

In addition, the inner wall can be disposed on the firing furnace in an open form as required, and the firing process can be performed in the firing furnace by covering the upper face of the inner wall with a lid. At this time, the cover and the through hole for the flow of the gas may be formed. By covering the lid in this way, it is possible to suppress the inflow of the foreign matter into the inner lid while having the through hole, so that the gas can be flown.

The method for producing the active material is not particularly limited as long as the method for producing the active material is generally applicable except for using the inner fingernail provided in the present invention. For example, in the inner fingernail according to the present invention A step of placing the raw material on a firing furnace and disposing an inner shell on which a fugitive substance is placed in the firing furnace; firing the firing furnace in an oxygen-containing gas atmosphere or an inert gas atmosphere; and firing the fired raw material in the inner firing furnace Followed by cooling and pulverizing to obtain a secondary battery active material.

At this time, the raw material can be used by being loaded on the inner wall of the fire wall in powder form, and the size of the raw material of the powder can be increased to be mounted on the inner wall.

Furthermore, the number of the inner fire wall to be disposed in the firing furnace may be one or more than two. At this time, the inner shell can be arranged as a single layer of a plurality of inner shells, or two or more inner shells can be stacked and arranged in two or more layers. Since the inner wall of the inner wall of the present invention is formed with a through hole at the bottom, even if two or more inner walls are stacked, the atmospheric gas introduced into the through hole of the bottom wall or the side wall of the inner wall of the lower layer, Through holes of the first and second heat exchangers.

Example

Hereinafter, the present invention will be described in more detail with reference to examples. The following examples illustrate one embodiment of the present invention, but the present invention is not limited thereto.

Example  One

As shown in Fig. 1, an inorganic firefly having 16 circular through holes having a diameter of 5 mm on the bottom was filled with raw material powder (LiOH) for manufacturing a cathode active material, and then placed in a firing furnace. The furnace was fired while introducing air as an oxygen-containing gas.

After firing, the inner wall was removed from the firing furnace and cooled to obtain a cathode active material.

The residual lithium amount and the coin cell characteristics were measured for the thus obtained positive electrode active material, and the results are shown in Table 1.

Comparative Example  One

A cathode active material was prepared by firing and cooling in the same manner as in Example 1, except that an inner shell having no through hole at the bottom was used.

The residual lithium amount and the coin cell characteristics were measured with respect to the produced positive electrode active material, and the results are shown in Table 1.

Example 1 Comparative Example 1 Residual LiOH (ppm) 600 1000 Residual Li ₂ CO ₃ (ppm) 1500 2500 Initial discharge capacity (mAh / g, @ 0.1C) 176 175 Initial Charge / Discharge Efficiency (%) 91 90 Cycle life (50 ^th / 1 ^st @ 1C) 98 97

As can be seen from the above Table 1, in the case of Example 1 using the inner fire wall with the through-hole formed on the bottom surface, the residual amount of LiOH and lithium carbonate was reduced to 30% as compared with Comparative Example 1 using the inner fire- Of the total. Furthermore, it can be seen that the initial discharge capacity, the initial charge / discharge efficiency, and the cycle life are improved in Example 1 as compared with Comparative Example 1, and the coin cell characteristics are improved.

Claims (9)

The bottom surface or the bottom surface and the wall surface has at least one through hole having a diameter of 1 to 50 mm for the flow of gas, and the total area of the through holes of the bottom surface is in the range of 0.1 to 20% Depositing a molded article having a diameter larger than the diameter of the through hole in the inner shell of the shell, and disposing an inner shell on which the shell is loaded, into the firing furnace;
Firing the firing furnace in an oxygen-containing gas atmosphere or an inert gas atmosphere; And
After firing, the fired fired material in the inner chamber is taken out from the firing furnace, cooled, and pulverized to obtain a secondary battery active material
≪ / RTI > The active material manufacturing method according to claim 1, wherein the through-hole of the wall surface is located at a half of the height of the inner wall from the bottom surface. The method of manufacturing an active material according to claim 1, wherein the through holes are circular, elliptical, polygonal, or a combination of two or more of them. The method of claim 1, wherein the inner shell is selected from the group consisting of mullite (3Al ₂ O ₃ 2SiO ₂ ), cordierite ((Mg, Fe ⁺³ ) ₂ Al ₄ Si ₅ O ₁₈ ), spinel (MgAl ₂ O ₄ ) ZrSiO4). ≪ / _RTI > The active material manufacturing method according to claim 1, wherein the inner shell is open for the inflow and outflow of the object to be cleaned on its upper surface, and has a cover covering the opened upper surface. 6. The method of manufacturing an active material according to any one of claims 1 to 5, wherein the refractory material has an increased size of a refractory material that is molded into a powder and loaded on the refractory. The method of manufacturing an active material according to any one of claims 1 to 5, wherein two or more fireproof boards are disposed and fired in the firing furnace. 6. The method of manufacturing an active material according to any one of claims 1 to 5, wherein two or more intumescent screens are stacked and fired in the firing furnace. delete

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