Apparatus and method for manufacturing positive electrode active material precursors

Abstract

This embodiment may include an apparatus and method for manufacturing a positive electrode active material precursor. An apparatus for manufacturing a positive electrode active material precursor according to one embodiment may include: a reaction unit 100 including a first reactor 110, an input pipe 120 for supplying raw material into the first reactor, a first stirring means 130 located in the center of the first reactor for stirring the raw material introduced from the input pipe to cause a coprecipitation reaction; a first connecting pipe 300 from which the reactants produced in the first reactor are discharged; a solid-liquid separation unit 200 including a second reactor 210, a second stirring means 230 located in the center of the second reactor for stirring the reactants introduced from the first connecting pipe, and a filtrate discharge section 220 located at the top of the second reactor; and a control unit connected to the reaction unit and the solid-liquid separation unit for controlling the reaction unit and the solid-liquid separation unit to be driven continuously.

Description

Technical Field

[0001] This embodiment relates to an apparatus and a method for manufacturing a cathode active material precursor.

Background Art

[0002] Not only small electronic devices such as smartphones, notebook computers, and tablet PCs, but recently, as the demand for electric vehicles and medium- and large-sized energy storage devices has increased, the demand for secondary batteries capable of storing electrical energy has been rapidly increasing. In particular, lithium secondary batteries that exhibit high energy density, operating potential, long cycle life, and low self-discharge rate are widely used.

[0003] Among the configurations of such lithium secondary batteries, the cathode active material is manufactured from a cathode material through a precursor manufactured from various component-based metal oxides such as nickel, cobalt, and manganese.

[0004] Although various methods for manufacturing the cathode active material have been proposed, the co-precipitation method using multi-component metal salts such as nickel, cobalt, and manganese as starting materials is the most economical and is utilized as a realistic method.

[0005] In addition, there is a batch-type apparatus for producing a precursor using the co-precipitation method. The batch-type apparatus takes 20 hours or more for 1RT, which is the time required to fill the reaction volume with an input source for particle growth and shape control, and it is possible to secure a precursor at a level of about 10% of the reaction weight based on the 1RT standard.

[0006] Therefore, when using an apparatus of this arrangement type, there is a problem that the productivity of the precursor per unit batch is very low. In addition, since the reaction volume continuously changes, the sphericity of the precursor also decreases.

Summary of the Invention

Problems to be Solved by the Invention

[0007] The objective of this embodiment is to provide a manufacturing apparatus and method for a cathode active material precursor that exhibits excellent spheroidization and significantly improves productivity. [Means for solving the problem]

[0008] A production apparatus for a positive electrode active material precursor according to one embodiment may include: a reaction unit 100 including a first reactor 110, an input pipe 120 for supplying raw material to the first reactor, a first stirring means 130 located in the center of the first reactor for stirring the raw material introduced from the input pipe to cause a coprecipitation reaction; a first connecting pipe 300 from which the reactants produced in the first reactor are discharged; a solid-liquid separation unit 200 including a second reactor 210, a second stirring means 230 located in the center of the second reactor for stirring the reactants introduced from the first connecting pipe, and a filtrate discharge section 220 located at the top of the second reactor; and a control unit connected to the reaction unit and the solid-liquid separation unit for controlling the reaction unit and the solid-liquid separation unit to be driven continuously.

[0009] The second reactor may include a first partition wall 251 provided at a predetermined distance from the inner wall of the second reactor.

[0010] The lower part of the first partition wall is integrally connected to a conical second partition wall 252, the second partition wall having a larger horizontal cross-sectional area towards the bottom of the second reactor.

[0011] The second reactor may include a stagnant area 260, which is an outer region, and a fluidized area 270, which is an inner region, partitioned by the first and second partitions.

[0012] The first connecting pipe can be positioned extending from the upper side wall of the first reactor to the upper part of the fluidized section.

[0013] The first partition wall has a height of 0.8 to 1 times the height of the second reactor, along the inner surface of the second reactor, and can be installed at a predetermined distance from the bottom surface of the second reactor.

[0014] The filtrate discharge section may include a filter member 221 located between the inner wall of the second reactor and the first partition wall.

[0015] The filter member can be positioned in a manner that floats above the second reactor.

[0016] The filtrate discharge section may include a filtrate discharge pipe 222 located on the side wall of the second reactor.

[0017] The filtrate discharge piping can be located on the side wall at a height of 0.9 to 1 times the total height of the first and second partitions from the bottom surface of the second reactor.

[0018] The system may further include a second connecting pipe 400 connected to the second reactor, which reintroduces the solids separated from the solid-liquid separation unit into the first reactor.

[0019] The input piping 120 may include a first input piping 121 for inputting a metal ion-containing solution, a second input piping 122 for inputting a basic aqueous solution, and a third input piping 123 for inputting an ammonium ion-containing solution.

[0020] The system may further include a filtrate recovery unit 600 connected to the filtrate discharge unit, which recovers the reaction filtrate separated from the solid-liquid separation unit.

[0021] The first stirring means includes a first shaft and a first impeller, the first impeller may be located in a region from the bottom surface of the first reactor to 5% to 20% of the volume of the first reactor.

[0022] The second stirring means 230 includes a second shaft 231 and a second impeller 232, and the lower end of the second impeller can be located in a region of 10% to 20% of the volume of the second reactor based on the bottom surface of the second reactor.

[0023] The volume of the second reactor may be 100% or more based on 100% of the volume of the first reactor.

[0024] A method for manufacturing a cathode active material precursor according to an embodiment includes: supplying a raw material substance including a metal ion-containing solution, a basic aqueous solution, and an ammonium ion-containing solution to a first reactor of a reaction unit; stirring the raw material substance using first stirring means to form a reaction product by a coprecipitation reaction; when the reaction solution containing the raw material substance in the first reactor reaches 100% or more based on the reaction volume region of the first reactor, discharging the excess through a first connection pipe to a second reactor of a solid-liquid separation unit; and removing the filtrate after solid-liquid separation of the reaction product introduced into the second reactor. The steps of supplying the raw material substance and removing the filtrate can be performed continuously.

[0025] The step of removing the filtrate can be performed after 70% or more of the total volume of the second reactor is charged with the reaction product.

[0026] The steps of supplying the raw material substance and removing the filtrate can be performed so as to satisfy the following formula (1). [Formula (1)] Supply amount of raw material substance ≥ Removal amount of filtrate

[0027] The step of removing the filtrate after solid-liquid separation of the reaction product introduced into the second reactor can be performed through a filter member located in a floating form at the upper part of the second reactor or a filtrate discharge pipe connected to the upper part of the second reactor.

[0028] In the step of solid-liquid separation of the reactants introduced into the second reactor, the solid content can settle and separate at the lower part of the stagnant part partitioned by a first partition provided at a predetermined distance from the inner wall of the second reactor and a second partition integrally connected to the lower part of the first partition.

[0029] The step of reintroducing the solid content obtained in the step of removing the filtrate after solid-liquid separation of the reactants introduced into the second reactor into the first reactor can be included.

[0030] The step of removing the filtrate after solid-liquid separation of the reactants introduced into the second reactor can include the step of stirring the reactants using second stirring means located at the center inside the second reactor.

[0031] The stirring speed using the second stirring means may be slower than or the same as the stirring speed using the first stirring means.

[0032] The positive electrode for a lithium secondary battery according to an embodiment can include a current collector; and a positive electrode active material layer located on at least one surface of the current collector and including a positive electrode active material manufactured using a positive electrode active material precursor manufactured according to an embodiment.

[0033] A lithium secondary battery according to an embodiment can include the positive electrode.

Advantages of the Invention

[0034] According to the present embodiment, by using a manufacturing apparatus for a positive electrode active material precursor that includes both a reaction unit that generates reactants through a coprecipitation reaction and a solid-liquid separation unit that discharges the filtrate through solid-liquid separation, and can continuously discharge the filtrate through the solid-liquid separation unit, the productivity of the positive electrode active material precursor can be dramatically improved.

[0035] Also, by reintroducing the solid content discharged to the solid-liquid separation unit into the reaction unit and manufacturing the precursor in a continuous process, it is easy to control the crystal growth surface, and thereby, a highly oriented positive electrode active material precursor can be manufactured.

[0036] Furthermore, the positive electrode active material precursor produced by this embodiment has the advantage of improving the physical properties of the positive electrode active material precursor because it has a uniform particle size and high sphericity. [Brief explanation of the drawing]

[0037] [Figure 1] This figure schematically shows a manufacturing apparatus for a positive electrode active material precursor according to one embodiment. [Figure 2] This figure shows the A-A' plane in Figure 1. [Figure 3] This is a magnified view of area B in Figure 1. [Figure 4] This figure schematically shows a manufacturing apparatus for a positive electrode active material precursor according to another embodiment. [Figure 5] This is a cross-sectional SEM image of cathode active material particles produced using a cathode active material precursor manufactured by the manufacturing method according to one embodiment and produced in a single circulation process. [Figure 6] This is a cross-sectional SEM image of cathode active material particles produced using a cathode active material precursor manufactured by the manufacturing method according to one embodiment and produced in a five-cycle process. [Figure 7] This is a cross-sectional SEM image of cathode active material particles manufactured using cathode active material precursors produced by a batch method. [Figure 8] This is an SEM image of cathode active material particles produced using cathode active material precursors manufactured in a batch method while maintaining a feeding rate of 100%. [Figure 9] Figure 8 shows a magnified SEM image of a single particle. [Figure 10] This is an SEM image of cathode active material particles produced using a cathode active material precursor manufactured by maintaining the input rate of raw materials to the reaction unit at 400%. [Figure 11] Figure 10 shows an SEM image of a single particle measured at a magnified view. [Figure 12]This is an SEM image of cathode active material particles produced using cathode active material precursors, which were manufactured in the first cycle by feeding raw materials into the reaction unit at a rate of 100%, and then in subsequent cycles by feeding raw materials into the reaction unit at a rate of 400%. [Figure 13] Figure 12 shows an SEM image of a single particle measured at a magnified view. [Modes for carrying out the invention]

[0038] The terms first, second, and third are used to describe various parts, components, regions, layers, and / or sections, but are not limited to these. These terms are used solely to distinguish one part, component, region, layer, or section from other parts, components, regions, layers, or sections. Accordingly, the first part, component, region, layer, or section described below may be referred to as the second part, component, region, layer, or section without departing from the scope of the invention.

[0039] The technical terms used herein are for the sole purpose of referring to specific embodiments and are not intended to limit the invention. The singular form used herein also includes the plural form unless the wording explicitly indicates the opposite. The meaning of “including” as used in this specification is to embody specific characteristics, regions, integers, steps, operations, elements, and / or components, and does not exclude the presence or addition of other characteristics, regions, integers, steps, operations, elements, and / or components.

[0040] When one part is described as being "on top of" or "above" another part, it does not mean that it is directly above or on top of the other part, and that other parts may be present between them. In contrast, when one part is described as being "directly above" another part, there is no other part in between them.

[0041] While not defined differently, all terms used herein, including technical and scientific terms, have the same meaning as those generally understood by a person of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries are additionally interpreted as having the meaning consistent with the relevant technical literature and the present disclosures, and are not interpreted in their ideal or highly formal sense unless otherwise defined.

[0042] Also, unless otherwise specified, % means weight percent, and 1 ppm is 0.0001 weight percent.

[0043] The embodiments of the present invention will be described below in detail so that those with ordinary skill in the art to which the present invention pertains can easily implement them. However, the present invention can be realized in various different forms and is not limited to the embodiments described herein.

[0044] The following describes each embodiment in detail.

[0045] Figure 1 is a schematic diagram of a manufacturing apparatus for a positive electrode active material precursor according to one embodiment, Figure 2 is a diagram showing the A-A' plane of Figure 1, and Figure 3 is a magnified view of region B of Figure 1.

[0046] Referring to Figures 1 to 3, the apparatus for producing a positive electrode active material precursor according to one embodiment may include a reaction unit 100, a solid-liquid separation unit 200, a first connecting pipe 300, and a control unit.

[0047] The reaction unit 100 may include a first reactor 110, an input pipe 120, and a first stirring means 130.

[0048] The first reactor 110 may have a circular horizontal cross-section and a cylindrical shape in three dimensions, with the upper and lower parts having the same diameter.

[0049] The input pipe 120 supplies the raw material to the inside of the first reactor 110.

[0050] Specifically, the input piping 120 may include a first input piping 121 for inputting a metal ion-containing solution, a second input piping 122 for inputting a basic aqueous solution, and a third input piping 123 for inputting an ammonium ion-containing solution.

[0051] The first stirring means 130 is located in the center of the first reactor 110. The first stirring means 130 stirs the raw material introduced into the first reactor 110 to generate a fluid flow, ensuring smooth mixing of the reactants. The stirred raw material reacts and is consumed by each other, producing precursor particles and reaction filtrate, which exist as a homogeneous phase within the first reactor 110.

[0052] At this time, the first stirring means 130 includes a first shaft 131 and a first impeller 132, and the first impeller 132 can be located in a region of 5% to 20% of the volume of the first reactor 110 from the bottom surface of the first reactor 110. Thus, the region of 5% to 20% of the volume of the first reactor 110 in which the first impeller 132 is located is the volume in which fluid flow can begin at the start of the reaction after the raw material is introduced. Therefore, after the first reactor 110 is filled with the raw material, the raw material starts reacting in the region by vortices induced by a component such as the first stirring means 130.

[0053] On the other hand, in this embodiment, the reaction volume region is defined as the area from 70% to 90% of the internal volume of the first reactor 110. Specifically, the reaction volume region may be in the range of 80% to 90% of the internal volume of the first reactor 110.

[0054] The reaction volume region refers to the region inside the first reactor 110 where the raw material is introduced, the reaction proceeds, and the reactant (RE1) increases and is discharged. The reaction volume region is the region where the volume of the raw material changes due to the reaction, and the flow changes inside the first reactor 110 affect the growth of the precursor. The higher the proportion of the reaction volume region, the greater the amount of precursor produced.

[0055] Next, the precursor particles and reaction filtrate, which are the reactants (RE1) produced in the first reactor 110, flow into the solid-liquid separation unit 200 via the first connecting pipe 300.

[0056] The solid-liquid separation unit 200 may include a second reactor 210, a second stirring means 230, and a filtrate discharge unit 220.

[0057] The second reactor 210 may have a circular horizontal cross-section and a cylindrical shape in three dimensions, with the upper and lower parts having the same diameter.

[0058] The volume of the second reactor 210 may be 100% or more of the volume of the first reactor 110, more specifically in the range of 100% to 300% or 200% to 300%.

[0059] When the volume of the second reactor 210 satisfies the aforementioned range, an additional reaction volume region can be secured in addition to the reaction volume region described above, thereby significantly improving the productivity of the positive electrode active material precursor.

[0060] In this embodiment, the region encompassing 70% to 90% of the internal volume of the second reactor 210 is defined as the additional reaction volume region. Specifically, the additional reaction volume region may be in the range of 80% to 90% of the internal volume of the second reactor 210.

[0061] Conventional reactor configurations utilize only about 70% to 80% of the reactor's internal volume as the reaction volume area, resulting in only about 10% of the reactants being produced as precursors. This leads to a problem of low precursor productivity per unit batch.

[0062] However, in this embodiment, it is possible to secure an additional reaction volume region in the second reactor 210 along with the reaction volume region in the first reactor 110, thereby significantly improving the productivity of the positive electrode active material precursor.

[0063] As mentioned above, the volume of the second reactor 210 can be the same as or larger than that of the first reactor 110, and the additional reaction volume region can be further increased depending on the size of the second reactor 210, which in turn can dramatically improve the productivity of the cathode active material precursor.

[0064] The second reactor 210 may include a first partition wall 251 provided at a predetermined distance from the inner wall of the second reactor 210. Furthermore, the lower part of the first partition wall 251 is integrally connected to a second conical partition wall 252, the second partition wall having a larger horizontal cross-sectional area towards the bottom surface of the second reactor 210.

[0065] Specifically, the first partition wall 251 has a height of 0.8 to 1 or 0.9 to 1 times the height of the second reactor 210, along the inner surface of the second reactor 210, and can be installed at a predetermined distance from the bottom surface of the second reactor 210.

[0066] Here, the area outside the second reactor 210, partitioned by the first partition wall 251 and the second partition wall 252, i.e., the edge region, can be defined as the stagnant region 260, and the inner region can be defined as the fluidized region 270.

[0067] Meanwhile, the first connecting pipe 300 extends from the upper side wall of the first reactor 110 to the fluidized section 270, which is the inner region of the second reactor 210 via the solid-liquid separation unit 200.

[0068] The second stirring means 230 is located in the center of the second reactor 210. The second stirring means 230 stirs the precursor particles and reaction filtrate, which are the reactants (RE1), introduced into the fluid section 270 of the second reactor 210 via the first connecting pipe 300, thereby generating a fluid flow.

[0069] At this time, the second stirring means 230 includes a second shaft 231 and a second impeller 232, and the lower end of the second impeller 232 can be located in a region from the bottom surface of the second reactor 210 to 10% to 20% of the volume of the second reactor 210. When the position of the second impeller 232 satisfies the above conditions, the flow of fluid contained in the reactants (RE1) that have flowed into the second reactor 210 via the second stirring means 230 can be initiated.

[0070] The reactant (RE1) that has passed into the fluid section 270 is a slurry-like fluid containing solid components. Specifically, the reactant (RE1) that flows into the fluid section 270 consists of solid components, i.e., precursor particles with a high specific gravity and a relatively light reaction filtrate. Therefore, if homogenization is not performed by the second stirring means 230, the second reactor 210 may become clogged due to solid sedimentation, potentially causing problems in the process.

[0071] Therefore, when the reaction mixture, which has been stirred and homogenized by the second stirring means 230 in the fluid section 270 of the second reactor 210, flows into the stagnant section 260, and the homogenized reaction mixture occupies a certain volume or more throughout the entire second reactor 210, a solid-liquid separation phenomenon occurs in which the homogenized reaction mixture that has flowed into the stagnant section 260 is separated into solids (S) and filtrate (RE3). As a result, the solids (S) settle (SS) at the bottom of the stagnant section 260, and the separated filtrate (RE3) can be removed via the filtrate discharge section 220 located at the upper end of the stagnant section 260.

[0072] In this embodiment, the volume of the stagnation section 260 is 5% or more, specifically in the range of 5% to 30%, 10% to 30%, or 20% to 30%, based on the sum of the reaction volume region of the first reactor 110 and the additional reaction volume region secured in the second reactor 210.

[0073] The total reaction volume region secured according to the size of the first reactor 110 and the second reactor 210 can be varied, and by forming the stagnation section 260 to fill the range with respect to the total reaction volume region, solid-liquid separation can be effectively performed.

[0074] Next, the solid-liquid separation unit 200 includes a filtrate discharge unit 220. The reactants flowing into the solid-liquid separation unit 200 are separated into solids and a reaction filtrate, of which the reaction filtrate is discharged to the outside via the filtrate discharge unit 220.

[0075] In this embodiment, the reaction filtrate is discharged via the filtrate discharge section 220, and at the same time, raw material substances are introduced into the reaction unit 100 to generate reactants. This allows for the securing of an additional reaction volume region in addition to the aforementioned reaction volume region, thereby dramatically improving the productivity of the positive electrode active material precursor in a single pass.

[0076] On the other hand, the filtrate discharge section 220 may include a filter member 221 located between the inner wall of the second reactor 210 and the first partition wall 251.

[0077] The filter member 221 can be positioned in a manner that floats above the second reactor 210. Specifically, it can be positioned in a manner that floats above the reaction filtrate of the reactants that have moved from the fluidized section 270 to the stagnant section 260 of the second reactor 210.

[0078] The filter component 221 may be, for example, a filtration filter, mesh, or membrane filter made of a corrosion-resistant material.

[0079] Next, the apparatus for producing the positive electrode active material precursor in this embodiment may further include a second connecting pipe 400 that is connected to a second reactor 210 and reintroduces the solid content (RE2) separated from the solid-liquid separation unit into the first reactor 110.

[0080] The second connecting pipe 400 can be located at the bottom or lower side wall of the second reactor 210. Since the solids (RE2) separated from the solid-liquid separation unit 200 are reintroduced to the first reactor 110 via the second connecting pipe 400, gradual growth control of the positive electrode active material precursor particles is possible, thereby enabling the acquisition of precursor particles with excellent sphericity and crystal orientation.

[0081] Furthermore, the positive electrode active material precursor manufacturing apparatus of this embodiment may further include a filtrate recovery unit 600 connected to the filtrate discharge unit 220, from which the reaction filtrate separated from the solid-liquid separation unit 200 is recovered.

[0082] The apparatus for producing the positive electrode active material precursor further includes a control unit (not shown) connected to the reaction unit 100 and the solid-liquid separation unit 200. The control unit can control the reaction unit 100 and the solid-liquid separation unit 200 to be driven continuously.

[0083] In this embodiment, continuous solid-liquid separation is possible via the solid-liquid separation unit 200. Therefore, by controlling the stirring speed of the reaction unit 100 to grow the positive electrode active material precursor particles to a small size in the reaction volume region, the reactants are moved to the solid-liquid separation unit 200, and the solids are reintroduced into the reaction unit 100 to gradually grow the precursor particles, thereby ensuring sphericity and crystal orientation.

[0084] Other embodiments will be described below with reference to drawings. In the embodiments described below, the same content as in the previously described embodiments will be omitted, and the focus will be on the differences. Also, the same reference numerals will be used for the same components as in the previous embodiments.

[0085] Figure 4 is a schematic diagram showing a manufacturing apparatus for a positive electrode active material precursor according to another embodiment. In this embodiment, the structure of the filtrate discharge section 220 differs from that of the embodiment described with reference to Figures 1 to 3.

[0086] In this embodiment, the filtrate discharge section 220 may include a filtrate discharge pipe 222 located on the side wall of the second reactor 210. The filtrate discharge pipe 222 can be located on the side wall at a height of 0.9 to 1 times the combined height of the first partition wall 251 and the second partition wall 252 from the bottom surface of the second reactor 210. By including the filtrate discharge pipe 222 in this way, filtrate (RE3) can be effectively discharged and the amount of filtrate discharged can be appropriately controlled.

[0087] Next, a method for producing a positive electrode active material precursor according to one embodiment may include the steps of: supplying a raw material containing a metal ion-containing solution, a basic aqueous solution, and an ammonium ion-containing solution to a first reactor of a reaction unit; stirring the raw material using a first stirring means to form a reactant by coprecipitation; discharging the excess of the reactant to a second reactor of a solid-liquid separation unit via a first connecting pipe when the reaction solution containing the raw material reaches 100% or more of the reaction volume region of the first reactor; and removing the filtrate after solid-liquid separation of the reactant introduced into the second reactor.

[0088] In this embodiment, the steps of supplying the raw material and removing the filtrate can be performed continuously.

[0089] First, the process involves supplying raw material materials containing a metal ion-containing solution, a basic aqueous solution, and an ammonium ion-containing solution to the first reactor of the reaction unit.

[0090] The metal ion-containing solution may contain, for example, cations of nickel (Ni), manganese (Mn), cobalt (Co), aluminum (Al), and one or more metals selected from various doped elements. The metal ion-containing solution may also contain acetates, nitrates, sulfates, halides, sulfides, hydroxides, oxides, or oxyhydroxides of the metal, and is not particularly limited as long as it is soluble in water.

[0091] For example, the cobalt (Co) may be contained in Co(OH)2, CoOOH, Co(OCOCH3)2·4H2O, Co(NO3)2·6H2O, CoSO4, or Co(SO4)2·7H2O, and one or more of these can be used in mixtures. The nickel (Ni) may be contained in Ni(OH)2, NiO, NiOOH, NiCO3·2Ni(OH)2·4H2O, NiC2O2·2H2O, Ni(NO3)2·6H2O, NiSO4, NiSO4·6H2O, fatty acid nickel salts, or nickel halides, and one or more of these can be used in mixtures. Furthermore, the manganese (Mn) may also consist of manganese oxides such as Mn2O3, MnO2, and Mn3O4; manganese salts such as MnCO3, Mn(NO3)2, MnSO4, manganese acetate, manganese dicarboxylate salts, manganese citrate, and manganese fatty acid salts; oxyhydroxides, and manganese chloride, and one or more of these can be used as a mixture.

[0092] The basic aqueous solution may contain one or more selected from alkali metal hydrates, alkali metal hydroxides, alkaline earth metal hydrates, and alkaline earth metal hydroxides. For example, the basic aqueous solution may contain NaOH, KOH, or Ca(OH)2, and as the solvent, water or a mixture of water and an organic solvent that is homogeneously miscible with water (specifically, an alcohol) may be used.

[0093] The ammonium ion-containing solution may contain one or more selected from NH4OH, (NH4)2SO4, NH4NO3, NH4Cl, CH3COONH4, and NH4CO3. As the solvent, water or a mixture of water and an organic solvent that is homogeneously miscible with water (specifically, such as an alcohol) may be used.

[0094] Next, when the reaction solution containing the raw material substance inside the first reactor reaches 100% or more of the reaction volume region of the first reactor, the excess is discharged to the second reactor of the solid-liquid separation unit via the first connecting pipe.

[0095] Subsequently, the reactants introduced into the second reactor are subjected to solid-liquid separation, followed by the removal of the filtrate.

[0096] The step of removing the filtrate can be performed after the reactants have been added to the second reactor to a volume of 70% or more, more specifically, between 70% and 90% of the total volume of the second reactor. Since the filtrate is removed when the reactants reach a volume of 70% or more of the total volume of the second reactor, the reactants that have flowed into the stagnant section do not flow, so the solids naturally settle to the bottom of the second reactor, making solid-liquid separation easier.

[0097] The step of removing the filtrate after solid-liquid separation of the reactants introduced into the second reactor may include a step of stirring the reactants using a second stirring means located in the center of the inside of the second reactor. By stirring the reactants that have flowed into the fluid section using the second stirring means, the reactants are homogenized, and a portion of the homogenized reactants are exchanged with each other at the lower end of the stagnant section.

[0098] At this time, the stirring speed using the second stirring means may be slower than or the same as the stirring speed using the first stirring means.

[0099] The reactants are homogenized by the fluid flow formed in the fluid section of the second reactor, and some of the homogenized reactants are exchanged with each other at the lower end of the stagnant section. Most of the area of ​​the stagnant section is unaffected by the fluid flow formed in the fluid section.

[0100] Specifically, in the process of separating the reactants introduced into the second reactor into solid and liquid components, the solid components settle and are separated in the lower part of a stagnation section partitioned by a first partition wall, which is provided at a predetermined distance from the inner wall of the second reactor, and a second partition wall, which is integrally connected to the lower part of the first partition wall.

[0101] The step of removing the filtrate after separating the reactants introduced into the second reactor into solid and liquid components can be performed via a filter member positioned in a floating manner above the second reactor, or via a filtrate discharge pipe connected to the upper part of the second reactor.

[0102] The steps of supplying the raw material and removing the filtrate can be carried out in such a way that the following formula 1 is satisfied. [Formula 1] Raw material supply amount ≧ Filtrate removal amount

[0103] Since the amount of raw material supplied is greater than or equal to the amount of filtrate removed, according to this embodiment, the cathode active material precursor can be manufactured in a continuous process. In this case, the amount of raw material supplied refers to the total amount of raw materials supplied.

[0104] On the other hand, the step of removing the filtrate after solid-liquid separation of the reactants introduced into the second reactor may include a step of reintroducing the separated solids into the first reactor.

[0105] By removing the reaction filtrate separated from the solid-liquid separation unit and reintroducing the solid components into the reaction unit, the positive electrode active material precursor particles can be gradually grown, thereby ensuring sphericity and crystal orientation.

[0106] Furthermore, it is possible to dramatically increase the production volume of cathode active material precursors.

[0107] In other embodiments, a current collector and a positive electrode located on one surface of the current collector, comprising a positive electrode active material manufactured using the positive electrode active material precursor manufactured according to the above-described embodiment, are provided.

[0108] The cathode active material, utilizing the cathode active material precursor, can be manufactured using conventional cathode active material manufacturing methods.

[0109] The current collector can be made of, for example, stainless steel, aluminum, nickel, titanium, calcined carbon, or aluminum or stainless steel with a surface treatment of carbon, nickel, titanium, silver, etc.

[0110] On the other hand, the positive electrode active material layer may include a binder and a conductive material.

[0111] At this time, the binder plays a role in improving the adhesion between positive electrode active material particles and the adhesion between the positive electrode active material and the positive electrode current collector. Specific examples include polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-co-HFP), polyvinyl alcohol, polyacrylonitrile, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene monomer rubber (EPDM rubber), sulfonated EPDM, styrene-butadiene rubber (SBR), fluororubber, or various copolymers thereof, and one or more of these may be used, but are not limited to these. The binder may be included in an amount of 1 to 30% by weight relative to the total weight of the positive electrode active material layer.

[0112] Furthermore, the conductive material is used to impart conductivity to the electrodes and can be used in any battery without particular limitations as long as it does not cause chemical changes and has electronic conductivity. Specific examples include graphite such as natural graphite or artificial graphite; carbon-based materials such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal black, and carbon fiber; metal powders or metal fibers such as copper, nickel, aluminum, and silver; conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; or conductive polymers such as polyphenylene derivatives. One of these may be used alone or in mixtures of two or more, but this is not limited to these examples. The conductive material may usually be included in an amount of 1 to 30% by weight relative to the total weight of the positive electrode active material layer.

[0113] The positive electrode can be manufactured by a conventional positive electrode manufacturing method, except that the positive electrode active material is used.

[0114] Specifically, the positive electrode can be manufactured by applying a composition for forming a positive electrode active material layer, which includes the positive electrode active material described above and optionally a binder, conductive material, or solvent, onto a positive electrode current collector, followed by drying and rolling. At this time, the types and contents of the positive electrode active material, binder, and conductive material are as previously described.

[0115] The solvent can be any solvent commonly used in the art, such as dimethyl sulfoxide (DMSO), isopropyl alcohol, N-methylpyrrolidone (NMP), acetone, or water, and one or more of these can be used individually or in mixtures of two or more. The amount of solvent used should be sufficient to dissolve or disperse the cathode active material, conductive material, and binder, taking into consideration the coating thickness and production yield of the slurry, and to have a viscosity that allows for excellent thickness uniformity during subsequent coating for cathode manufacturing.

[0116] As yet another method, the positive electrode may be manufactured by casting the positive electrode active material layer forming composition onto a separate support, peeling it off the support, and then laminating the resulting film onto the positive electrode current collector.

[0117] In yet another embodiment, a lithium secondary battery including the positive electrode is provided.

[0118] The lithium secondary battery may specifically include a positive electrode, a negative electrode positioned opposite the positive electrode, a separator interposed between the positive and negative electrodes, and an electrolyte, wherein the positive electrode is as described above. The lithium secondary battery may also selectively further include a battery container housing the electrode assembly including the positive electrode, negative electrode, and separator, and a sealing member for sealing the battery container.

[0119] In the lithium secondary battery, the negative electrode may include a negative electrode current collector and a negative electrode active material layer located on the negative electrode current collector.

[0120] The negative electrode current collector is not particularly limited as long as it does not cause chemical changes in the battery and has high conductivity. For example, copper, stainless steel, aluminum, nickel, titanium, calcined carbon, copper or stainless steel surface treatment with carbon, nickel, titanium, silver, etc., and aluminum-cadmium alloy can be used. The negative electrode current collector can usually have a thickness of 3 to 500 μm, and, similar to the positive electrode current collector, fine irregularities can be formed on the surface of the current collector to strengthen the bonding force of the negative electrode active material. For example, it can be used in various forms such as film, sheet, foil, net, porous material, foam, and nonwoven fabric.

[0121] The negative electrode active material layer may selectively include a binder and a conductive material together with the negative electrode active material. For example, the negative electrode active material layer may be manufactured by applying a negative electrode active material layer forming composition, which includes the negative electrode active material and selectively a binder and a conductive material, onto a negative electrode current collector and drying it, or by casting the negative electrode forming composition onto a separate support, peeling it off the support, and then laminating the resulting film onto the negative electrode current collector.

[0122] As the negative electrode active material, compounds capable of reversible intercalation and deintercalation of lithium can be used. Specific examples include carbonaceous materials such as artificial graphite, natural graphite, graphitized carbon fiber, and amorphous carbon; metallic compounds capable of alloying with lithium, such as Si, Al, Sn, Pb, Zn, Bi, In, Mg, Ga, Cd, Si alloys, Sn alloys, or Al alloys; and SiO2. β Examples include metallic oxides that can be doped and dedoped with lithium, such as (0<β<2), SnO2, vanadium oxide, and lithium vanadium oxide; or composites containing the metallic compound and carbonaceous material, such as Si-C composites or Sn-C composites, and any one or more mixtures of these can be used. Furthermore, a metallic lithium thin film can be used as the negative electrode active material. In addition, both low-crystalline carbon and high-crystalline carbon can be used as the carbon material. Typical examples of low-crystalline carbon include soft carbon and hard carbon, while typical examples of high-crystalline carbon include amorphous, plate-like, flake-like, spherical, or fibrous natural or artificial graphite, Kish graphite, pyrolytic carbon, mesophase pitch-based carbon fiber, meso-carbon microbeads, mesophase pitches, and high-temperature calcined carbon such as petroleum or coal tar pitch-derived cokes.

[0123] The aforementioned binder and conductive material are the same as those described earlier for the positive electrode.

[0124] Next, depending on the type of lithium secondary battery, a separator may be present between the positive and negative electrodes. Such separators can be polyethylene, polypropylene, polyvinylidene fluoride, or multilayer films of two or more layers of these materials. Mixed multilayer films such as polyethylene / polypropylene two-layer separators, polyethylene / polypropylene / polyethylene three-layer separators, and polypropylene / polyethylene / polypropylene three-layer separators can also be used.

[0125] Furthermore, in the lithium secondary battery, the electrolyte can be an organic liquid electrolyte, an inorganic liquid electrolyte, a solid polymer electrolyte, a gel-type polymer electrolyte, a solid inorganic electrolyte, or a molten inorganic electrolyte, but is not limited to these.

[0126] Specifically, the organic liquid electrolyte may contain an organic solvent and a lithium salt.

[0127] The organic solvent can be any solvent that can act as a medium through which ions involved in the electrochemical reaction of the battery can move, without any particular limitations. Specifically, the organic solvents include ester solvents such as methyl acetate, ethyl acetate, γ-butyrolactone, and ε-caprolactone; ether solvents such as dibutyl ether or tetrahydrofuran; ketone solvents such as cyclohexanone; aromatic hydrocarbon solvents such as benzene and fluorobenzene; dimethyl carbonate (DMC), diethyl carbonate (DEC), and methyl ethyl carbonate. Carbonate solvents such as bonate (MEC), ethyl methyl carbonate (EMC), ethylene carbonate (EC), and propylene carbonate (PC); alcohol solvents such as ethyl alcohol and isopropyl alcohol; nitriles such as R-CN (where R is a C2-C20 linear, branched, or cyclic hydrocarbon group, and may include a double-bonded aromatic ring or ether bond); amides such as dimethylformamide; dioxolanes such as 1,3-dioxolane; or sulfolanes can be used. Among these, carbonate solvents are preferred, and a mixture of a cyclic carbonate (e.g., ethylene carbonate or propylene carbonate) having high ionic conductivity and high dielectric constant that can improve the charge and discharge performance of the battery, and a low-viscosity linear carbonate compound (e.g., ethyl methyl carbonate, dimethyl carbonate, or diethyl carbonate) is more preferred. In this case, mixing cyclic carbonates and linear carbonates in a volume ratio of approximately 1:1 to 1:9 can result in superior electrolyte performance.

[0128] The lithium salt can be any compound capable of providing lithium ions for use in lithium secondary batteries, without any particular limitations. Specifically, the lithium salt can be LiPF6, LiClO4, LiAsF6, LiBF4, LiSbF6, LiAlO4, LiAlCl4, LiCF3SO3, LiC4F9SO3, LiN(C2F5SO3)2, LiN(C2F5SO2)2, LiN(CF3SO2)2, LiCl, LiI, or LiB(C2O4)2, etc. The concentration of the lithium salt is preferably within the range of 0.1 to 2.0 M. When the concentration of the lithium salt falls within this range, the electrolyte has appropriate conductivity and viscosity, exhibiting excellent electrolyte performance and allowing lithium ions to move effectively.

[0129] As described above, the lithium secondary battery containing the positive electrode active material according to the present invention exhibits excellent discharge capacity, output characteristics, and capacity retention rate stably, making it useful in portable devices such as mobile phones, laptop computers, and digital cameras, as well as in the electric vehicle field, such as hybrid electric vehicles (HEVs). [Examples]

[0130] Examples The following describes embodiments of the present invention in detail. However, these are presented as examples only and do not limit the present invention; the present invention is defined only by the scope of the claims described below.

[0131] Experimental example

[0132] Particle characterization

[0133] Figures 5 and 6 are cross-sectional SEM images of positive electrode active material particles produced using a positive electrode active material precursor manufactured using a manufacturing apparatus according to one embodiment. Figure 5 shows a single-cycle process in which the reactants are generated in a reaction unit and then passed to a solid-liquid separation unit to obtain the separated solids, i.e., the precursor. Figure 6 shows a process in which the precursor is produced using a five-cycle process.

[0134] Figure 7 is a cross-sectional SEM image of cathode active material particles produced using cathode active material precursors manufactured by a batch method.

[0135] Referring to Figures 5 to 7, it can be confirmed that the crystal orientation of the positive electrode active material particles in Figures 5 and 6 is superior to that of the positive electrode active material particles in Figure 7.

[0136] Figure 8 is an SEM image of cathode active material particles produced using cathode active material precursors manufactured in a batch method while maintaining a feeding rate of 100%, and Figure 9 is an SEM image of a single particle measured at a magnified level in Figure 8.

[0137] Figures 10 to 13 are SEM images of a cathode active material produced using a cathode active material precursor manufactured by the manufacturing method according to one embodiment.

[0138] Specifically, Figure 10 is an SEM image of cathode active material particles produced using a cathode active material precursor manufactured by maintaining the raw material input rate to the reaction unit at 400%, and Figure 11 is an SEM image of a single particle from Figure 10, magnified and measured.

[0139] Figure 12 is an SEM image of cathode active material particles produced using cathode active material precursors, which were first produced in the first cycle by feeding raw materials into the reaction unit at a rate of 100%, and then in the second cycle by feeding raw materials into the reaction unit at a rate of 400%. Figure 13 is an SEM image of a single particle from Figure 12, magnified.

[0140] Referring to Figures 10 to 13, it can be confirmed that the sphericity is superior compared to Figures 9 and 10.

[0141] Precursor synthesis results

[0142] A 5L glass reactor was prepared to serve as both a reaction unit and a solid-liquid separation unit.

[0143] 60 L of the reaction mixture (solid content 10%) was added to confirm whether solid-liquid separation occurred and to check the extent to which solid-liquid separation was possible.

[0144] It was confirmed that solid-liquid separation is possible down to the 5RT level (50% solid content level) when applying a feed rate condition of 1RT 5hr. Therefore, it was confirmed that continuous solid-liquid separation has the potential to increase the yield per unit batch by more than five times.

[0145] The present invention is not limited to the embodiments described above, and can be manufactured in a variety of different forms. A person with ordinary skill in the art to which the present invention belongs will understand that it can be carried out in other specific forms without altering the technical idea or essential features of the present invention. Accordingly, the embodiments described below should be understood to be illustrative and not limiting in all respects. [Explanation of Symbols]

[0146] 100: Reaction Unit 200: Solid-liquid separation unit 110: Reactor No. 1 120: Input piping 130: First stirring means 300: First connecting piping 210: Reactor No. 2 220:Filtrate discharge part 230:Second stirring means 251: 1st bulkhead 252:Second bulkhead 260: Stagnation part 270: Fluid section

Claims

1. A reaction unit comprising a first reactor, an input pipe for supplying raw material substances into the first reactor, and a first stirring means located in the center of the first reactor for stirring the raw material substances supplied from the input pipe to cause a coprecipitation reaction; A first connecting pipe from which the reactants produced in the first reactor are discharged; A second reactor, a second stirring means located in the center of the second reactor for stirring the reactants introduced from the first connecting pipe, and a solid-liquid separation unit including a filtrate discharge section located at the top of the second reactor; and A control unit connected to the reaction unit and the solid-liquid separation unit, which controls the reaction unit and the solid-liquid separation unit to operate continuously; A manufacturing apparatus for cathode active material precursors, including the component mentioned above.

2. The apparatus for producing a positive electrode active material precursor according to claim 1, wherein the second reactor includes a first partition wall provided at a predetermined distance from the inner wall of the second reactor.

3. The apparatus for producing a positive electrode active material precursor according to claim 2, wherein the lower part of the first partition wall is integrally connected to a conical second partition wall whose horizontal cross-sectional area increases towards the bottom surface of the second reactor.

4. The apparatus for producing a positive electrode active material precursor according to claim 3, wherein the second reactor includes a stagnant region which is an outer region and a fluid region which is an inner region, partitioned by the first partition and the second partition.

5. The apparatus for producing a positive electrode active material precursor according to claim 1, wherein the first connecting pipe extends from the upper side wall of the first reactor to the upper part of the fluidized section.

6. The apparatus for producing a positive electrode active material precursor according to claim 1, wherein the first partition wall is provided along the inner surface of the second reactor, having a height of 0.8 to 1 times the height of the second reactor, and is spaced at a predetermined distance from the bottom surface of the second reactor.

7. The apparatus for producing a positive electrode active material precursor according to claim 1, wherein the filtrate discharge section includes a filter member located between the inner wall of the second reactor and the first partition wall.

8. The apparatus for producing a positive electrode active material precursor according to claim 7, wherein the filter member is positioned in a manner that floats above the second reactor.

9. The apparatus for producing a positive electrode active material precursor according to claim 3, wherein the filtrate discharge section includes a filtrate discharge pipe located on the side wall of the second reactor.

10. The apparatus for producing a positive electrode active material precursor according to claim 9, wherein the filtrate discharge pipe is located on the side wall at a height of 0.9 to 1 times the total height of the first and second partitions from the bottom surface of the second reactor.

11. The apparatus for producing a positive electrode active material precursor according to claim 1, further comprising a second connecting pipe connected to the second reactor for reintroducing the solids separated from the solid-liquid separation unit into the interior of the first reactor.

12. The aforementioned input piping is First input pipe for introducing metal ion-containing solution, A second input pipe for introducing a basic aqueous solution, and The apparatus for producing a positive electrode active material precursor according to claim 1, comprising a third input pipe for introducing an ammonium ion-containing solution.

13. The apparatus for producing a positive electrode active material precursor according to claim 1, further comprising a filtrate recovery unit connected to the filtrate discharge unit, for recovering the reaction filtrate separated from the solid-liquid separation unit.

14. The first stirring means includes a first shaft and a first impeller, The apparatus for producing a positive electrode active material precursor according to claim 1, wherein the first impeller is located in a region from the bottom surface of the first reactor to 5% to 20% of the volume of the first reactor.

15. The second stirring means includes a second shaft and a second impeller, The apparatus for producing a positive electrode active material precursor according to claim 1, wherein the lower end of the second impeller is located in a region of 10% to 20% of the volume of the second reactor, with reference to the bottom surface of the second reactor.

16. The apparatus for producing a positive electrode active material precursor according to claim 1, wherein the volume of the second reactor is 100% or more of the volume of the first reactor.

17. A step of supplying raw material materials containing a metal ion-containing solution, a basic aqueous solution, and an ammonium ion-containing solution to the first reactor of the reaction unit; A step of stirring the raw material using a first stirring means to form a reactant by coprecipitation; When the reaction solution containing the raw material substance inside the first reactor reaches 100% or more of the reaction volume region of the first reactor, the excess is discharged to the second reactor of the solid-liquid separation unit via the first connecting pipe; and The step of separating the reactants introduced into the second reactor into solid and liquid components and then removing the filtrate; A method for producing a positive electrode active material precursor, wherein the steps of supplying the raw material and removing the filtrate are performed continuously.

18. The step of removing the filtrate is, A method for producing a positive electrode active material precursor according to claim 17, wherein the method is carried out after 70% or more of the total volume of the second reactor has been introduced.

19. A method for producing a positive electrode active material precursor according to claim 17, wherein the steps of supplying the raw material and removing the filtrate are performed in such a manner that the following formula 1 is satisfied. [Formula 1] Raw material supply amount ≧ Filtrate removal amount

20. The step of separating the reactants introduced into the second reactor into solid and liquid components and then removing the filtrate is as follows: A filter member positioned in a floating form above the second reactor, or A method for producing a positive electrode active material precursor according to claim 17, which is carried out via a filtrate discharge pipe connected to the upper part of the second reactor.

21. In the process of separating the reactants introduced into the second reactor into solid and liquid components, the solid component is: A method for producing a positive electrode active material precursor according to claim 17, wherein the precursor settles and separates in the lower part of a stagnation section partitioned by a first partition wall provided at a predetermined distance from the inner wall of the second reactor, and a second partition wall integrally connected to the lower part of the first partition wall.

22. A method for producing a positive electrode active material precursor according to claim 17, comprising the step of reintroducing the solid content obtained in the step of removing the filtrate after solid-liquid separation of the reactants introduced into the second reactor into the first reactor.

23. The step of separating the reactants introduced into the second reactor into solid and liquid components and then removing the filtrate is as follows: A method for producing a positive electrode active material precursor according to claim 17, comprising the step of stirring the reactants using a second stirring means located in the center of the second reactor.

24. The method for producing a positive electrode active material precursor according to claim 23, wherein the stirring speed using the second stirring means is slower than or equal to the stirring speed using the first stirring means.

25. Current collector; and A positive electrode active material layer located on at least one surface of the current collector, comprising a positive electrode active material manufactured using a positive electrode active material precursor manufactured according to any one of claims 17 to 23; A positive electrode for lithium secondary batteries, including the component shown.

26. A lithium secondary battery comprising the positive electrode described in claim 25.

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