Reaction kettle for realizing controllable growth of high-nickel precursor crystal face

Abstract

The utility model relates to the technical field of reaction equipment, in particular to a reaction kettle for realizing controllable growth of a high-nickel precursor crystal face, which comprises a kettle body, a stirring component and baffles, the four baffles are detachably mounted on the inner wall of the kettle body at equal intervals, and the center lines of the baffles are parallel to the vertical center line of the kettle body. The baffle is selected from any one of a flow penetrating plate, a flow surrounding plate and a bent plate. According to the utility model, the flow field in the kettle body is improved and the mixing effect is enhanced through the baffle plate which is detachably mounted in the kettle body, so that the precursor primary particles can preferentially grow along the dominant crystal face (101) under the condition that the conventional hydroxide co-precipitation synthesis process flow and parameter conditions are not changed, the diffraction peak intensity (101) is highest, and the performance of the reaction kettle is improved. Meanwhile, the turbulence energy and shear stress of an area nearby the baffle are adjusted through the flow penetrating plate, the flow detour plate or the bending plate, the exposure ratio of the crystal face (001) can be adjusted and controlled, the diffraction peak intensity ratio of I (001) / I (101) can be controllably prepared within the range of 0.75-0.91, and therefore the type of the baffle can be selected according to needs on the basis.

Description

TECHNICAL FIELD

[0001] The utility model relates to reaction equipment technical field especially relates to the reaction kettle for realizing high nickel precursor crystal face controllable growth. BACKGROUND

[0002] At present, the positive material of lithium ion battery is upgrading towards high nickel, high pressure and single crystal, which brings high energy density, safety performance improvement and cost reduction, but also increases the process difficulty of material production, and puts forward higher requirements on precursor synthesis, doping, coating and other aspects. The precursor production process can be divided into batch method and continuous method. The batch method produces precursor with very narrow particle size distribution, and the continuous method has higher production capacity. The batch method produces material with uniform residence time in the reaction kettle, and produces precursor with narrower particle size distribution, which is suitable for producing high-end products such as high nickel and single crystal precursor products; but it has the disadvantages of poor production continuity and poor batch stability. The continuous method has higher production rate, and the production capacity of the same volume reaction kettle is about twice that of the batch method, and the batch stability is good; but due to the feeding and discharging at the same time, the residence time of the material in the reaction kettle is wide, and the particle size distribution of the produced precursor is also wide, especially some particles with too small particle size, which will cause overburning in the positive sintering process, thereby affecting the quality of the positive electrode.

[0003] In recent years, among the many positive materials with high energy density, low cost and low Co content, the quaternary high nickel layered oxide LiNi x Co y MnzAl 1-x–y-z O2(NCMA, x>0.8) has attracted widespread attention, but also has the problem of unstable structure. The NCMA secondary spherical particles composed of primary particles have random orientation and dense aggregation of crystal faces, and the intergranular stress mainly occurring at the grain boundary will accumulate with the volume expansion, which will stimulate the formation of cracks, and finally lead to poor cycle stability.

[0004] Because the microstructure determines the performance of NCMA material, and its structural characteristics are inherited from the precursor, the controllable preparation of different crystal face exposure of the precursor is particularly important. Studies have shown that crystal face exposure can induce structure attenuation and improve electrochemical performance. High exposure of {010} face is beneficial to the improvement of rate performance, and adjusting the growth of particles along

[003] (or

[001] ) direction can significantly improve the structural stability of the material, but how to directional control the crystal face exposure ratio of primary particles through the synthesis process remains to be explored.

[0005] In the prior art, a patent with the patent number CN109225069A discloses a preparation device for small particle size and high tapability ternary precursor, which improves the problem of uneven product particle size caused by uneven stirring by increasing the anti-deposition device at the bottom of the reaction kettle, and the change of the nucleation growth environment accompanying the change of the flow field makes the dominant crystal face fully grow, but this method has high modification cost and reduces the effective volume of the reaction kettle. Practical new type content

[0006] Therefore, the reaction kettle for realizing controllable growth of the crystal face of high-nickel precursor is provided, the flow field in the kettle is improved by the arrangement of the internal baffle, the material mixing effect is enhanced, the exposure ratio of the (001) crystal face is regulated while ensuring the full growth of the dominant crystal face, and then the layered positive electrode material with controllable (003) crystal face can be obtained.

[0007] The technical problems are solved by the following technical means in the utility model:

[0008] The utility model discloses a reaction kettle for realizing controllable growth of the crystal face of high-nickel precursor, including:

[0009] Kettle body;

[0010] Stirring assembly is used for stirring the material in the kettle body;

[0011] Baffle, four baffle has, four the baffle equidistance detachable installation is on the inner wall of kettle body, the center line of baffle is parallel with the vertical center line of kettle body, the baffle is selected from the flow -through plate, the flow -around plate and the bending plate in any one.

[0012] Further, the flow -through plate, the flow -around plate and the bending plate all include straight plate, one side of straight plate is close to the inner wall of kettle body and installs along the radial direction of kettle body.

[0013] Further, the straight plate has two mounting holes, and the detachable installation of the straight plate on the inner wall of the kettle body is realized by threading the bolts in the mounting holes.

[0014] Further, the straight plate of the flow -through plate has at least one through hole.

[0015] Further, the through hole on the flow -through plate has five, and the five through holes are equidistantly distributed on the straight plate of the flow -through plate.

[0016] Further, the straight plate of the flow -around plate is provided with a triangular protrusion, the triangular protrusion is a right-angled triangular protrusion, and the triangular protrusion is located on the side of the flow -around plate facing the stirring assembly.

[0017] Further, the triangular protrusions have upper and lower two, and a straight angle surface of the triangular protrusion forms a 45° angle with a straight plate side surface of the flow-around plate.

[0018] Further, two of the flow-around plates are installed on the inner wall of the kettle body in a forward direction, and the other two of the flow-around plates are installed on the inner wall of the kettle body in a reverse direction, the triangular protrusions of the flow-around plates installed in the forward direction are inclined upward, and the triangular protrusions of the flow-around plates installed in the reverse direction are inclined downward.

[0019] Further, a straight plate of the bent plate is connected with a branch plate, the length of the straight plate of the bent plate is the same as the length of the branch plate, one end of the straight plate of the bent plate, which is away from the inner wall of the kettle body, is connected with the branch plate, and the straight plate of the bent plate and the branch plate are connected in a circular arc transition.

[0020] Further, the included angle between the straight plate of the bent plate and the branch plate is 135°.

[0021] The reaction kettle of the utility model, through the flow-through plate or the flow-around plate or the bent plate which can be detachably installed inside the kettle body, under the stirring of the stirring assembly, the flow field inside the kettle body is improved, the mixing effect is enhanced, under the condition that the conventional hydrogen oxide coprecipitation synthesis process and parameter condition are not changed, the precursor particles can be realized to grow along the preferential crystal surface (101) first, the (101) diffraction peak intensity is the highest, and through the adjustment of the turbulent kinetic energy and the shear stress of the area near the baffle of the three different baffle types (the flow-through plate, the flow-around plate or the bent plate), the exposure ratio of the (001) crystal surface can be controlled, so that the diffraction peak intensity ratio of I(001) / I(101) can be controlled in the range of 0.75-0.91, thereby the baffle type can be selected according to the need, and the reaction kettle of the utility model can be used without changing the existing production line, the exposure ratio of the (001) crystal surface can be controlled while ensuring the full growth of the preferential crystal surface, and then the layered positive electrode material with controllable (003) crystal surface can be obtained. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is a structure schematic view of the reaction kettle of example 1;

[0023] Figure 2 It is a structure schematic view of the reaction kettle of example 2;

[0024] Figure 3 It is a structure schematic view of the bent plate of example 3;

[0025] Figure 4 It is an XRD graph of the quaternary precursor material obtained by the reaction of each reaction kettle;

[0026] Figure 5 It is an XRD graph of each quaternary layered positive electrode material;

[0027] The kettle body 100, the stirring assembly 200, the stirring shaft 210, the stirring paddle 220, the flow-through plate 310, the through hole 311, the mounting hole 312, the flow-around plate 320, the triangular protrusion 321, and the bent plate 330. DETAILED DESCRIPTION

[0028] The advantages and effects of the present application can be understood by those skilled in the art from the disclosure of the present application. It should be noted that the drawings provided in the following examples are only used for illustrative purposes, and the drawings represent only schematic diagrams, not physical drawings, and should not be construed as limiting the present application. In order to better illustrate the embodiments of the present application, some components in the drawings may be omitted, enlarged or reduced, and do not represent the actual size of the product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0029] The same or similar reference numerals in the drawings of the embodiments of the present application correspond to the same or similar components. In the description of the present application, it should be understood that the orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "front", "back" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and therefore the terms used to describe the positional relationship in the drawings should not be construed as limiting the present application to a specific orientation, construction and operation of the device or element indicated or implied, and therefore the terms used to describe the positional relationship in the drawings should only be used for illustrative purposes, and should not be construed as limiting the present application. For those skilled in the art, the specific meanings of the above terms can be understood according to the specific circumstances.

[0030] Embodiment 1

[0031] Please refer to Figure 1 The reaction kettle for realizing controllable growth of high-nickel precursor crystal faces of the present embodiment includes a kettle body 100, a stirring assembly 200 and a baffle. The kettle wall of the kettle body 100 is a double-layer vacuum insulation kettle wall made of stainless steel. The stirring assembly 200 is used to stir the materials inside the kettle body 100. The stirring assembly 200 includes a stirring shaft 210 and a stirring paddle 220. The stirring paddle 220 is fixed on the stirring shaft 210 and located inside the kettle body 100. The stirring shaft 210 is connected with a motor outside the kettle body 100. The motor rotates to drive the stirring shaft 210 to rotate, thereby driving the stirring paddle 220 to stir the materials inside the kettle body 100. The stirring paddle 220 is a paddle type stirring paddle or a propeller type stirring paddle. Preferably, the stirring paddle 220 is provided with two layers. The distance between the two layers of stirring paddles 220 is 180 mm. Each stirring paddle 220 has three or four blades.

[0032] The baffles are provided with four, four baffles are installed on the inner wall of the kettle body 100, namely the top end of the four baffles is on the same horizontal line, the bottom end of the four baffles is also on the same horizontal line, the bottom end of the baffle is aligned with the kettle bottom elliptical sealing layer. Four baffles are installed on the inner wall of the kettle body 100 at equal distance, the center line of the baffle is parallel to the vertical center line of the kettle body 100, that is, the baffle is installed in the vertical state inside the kettle body 100. The baffle of the embodiment is a flow-through plate 310, which is a straight plate with a through hole 311, the thickness of the straight plate is 2-5mm, one side of the straight plate is close to the inner wall of the kettle body 100 and is installed along the radial direction of the kettle body 100, that is, the tangent line of the straight plate in contact with the inner wall of the kettle body 100 is installed vertically. The straight plate is made of 316 stainless steel, the height is 350mm, the thickness is 3mm, and the width is 36mm. The straight plate has two installation holes 312 with a diameter of 7mm, the two installation holes 312 are respectively 80mm away from the top end and the bottom end of the straight plate and are symmetrically distributed, the straight plate is fixed in the inner wall of the kettle body 100 by screwing a standard bolt M7 in the installation hole 312, and the straight plate can be disassembled by unscrewing the bolt.

[0033] The straight plate of the flow-through plate 310 has at least one circular through hole 311, the diameter of the through hole 311 is 15-20mm, preferably 18mm. The straight plate of the flow-through plate 310 has five through holes 311 in this embodiment, the center of the first through hole 311 close to the top end of the straight plate is 20-25mm away from the top end of the straight plate, preferably 22mm, and the five through holes 311 are distributed at equal intervals on the straight plate of the flow-through plate 310. The straight plate on the through hole 311 balances the excessive turbulent energy of the baffle edge.

[0034] Embodiment 2

[0035] See Figure 2The difference between the embodiment and the embodiment 1 is the structure of the baffle. The baffle of the embodiment is the flow-around baffle 320, and the distribution and installation of the baffle are the same as those of the embodiment 1. The flow-around baffle 320 of the embodiment also includes a straight plate made of 316 stainless steel, which has a height of 350 mm, a thickness of 3 mm, and a width of 36 mm. The straight plate of the flow-around baffle 320 is provided with a triangular protrusion 321 inclined thereon, which is integrally formed with the straight plate of the flow-around baffle 320. The triangular protrusion 321 is a right-angled triangular protrusion 321, which is located on the side of the flow-around baffle 320 facing the stirring assembly 200. The triangular protrusion 321 has two upper and lower parts, and a straight side of the triangular protrusion 321 forms a 45° angle with the side of the straight plate of the flow-around baffle 320. The length of the straight side of the triangular protrusion 321 is 25 mm, and the height from the bottom side of the triangular protrusion 321 to the vertex thereof is 24 mm, i.e., the widest part of the flow-around baffle 320 is 60 mm. The increased position is the upper end of the short side and the lower edge of the two mounting holes 312, i.e., the first distance from the upper end of the baffle is 83.5 mm, and the distance from the vertex of the lower short side to the lower end of the baffle is 76.5 mm. The plane where the vertex of the triangular protrusion 321 is located is flush with the lowermost end of the mounting hole 312.

[0036] The two flow-around baffles 320 are installed on the inner wall of the kettle body 100 in the forward direction, and the other two flow-around baffles 320 are installed on the inner wall of the kettle body 100 in the reverse direction. The triangular protrusions 321 of the flow-around baffles 320 installed in the forward direction are inclined upward, the triangular protrusions 321 of the flow-around baffles 320 installed in the reverse direction are inclined downward, and the installation directions of the two flow-around baffles 320 in the same radial direction are opposite. The direction of the triangular protrusion 321 is inclined upward, and the structure of the kettle body 100 is centrally symmetric. One of the four baffle positions can be arbitrarily selected for first installation. The specific installation method is that after one flow-around baffle 320 is installed in the forward direction, the baffle position 180° opposite to the flow-around baffle 320 is installed in the reverse direction, i.e., the flow-around baffle 320 is inverted, the direction of the triangular protrusion 321 is inclined downward, the clockwise 90° baffle position of the first flow-around baffle 320 installed in the forward direction is also installed in the forward direction, the radially opposite baffle position is also installed in the reverse direction, and all the baffles are installed with the outer extension part facing the center of the kettle.

[0037] Embodiment 3

[0038] See Figure 3 The difference between the embodiment and the embodiment 1 is also the structure of the baffle. The baffle of the embodiment is the bent baffle 330, and the distribution and installation of the baffle are the same as those of the embodiment 1. The bent baffle 330 of the embodiment also includes a straight plate made of 316 stainless steel, which has a height of 350 mm, a thickness of 3 mm, and a width of 36 mm.

[0039] The straight plate of the bending plate 330 is connected with a branch plate 331, the length of the straight plate of the bending plate 330 is the same as the length of the branch plate 331, the end of the straight plate of the bending plate 330 away from the inner wall of the kettle body 100 is connected with the branch plate 331, and the straight plate of the bending plate 330 and the branch plate 331 are connected in a circular arc transition. The included angle between the straight plate of the bending plate 330 and the branch plate 331 is 135°, the width of the branch plate 331 is 30 mm, and the thickness is 3 mm. The specific installation direction of the baffle plate in this embodiment is that the non-planar branch plate 331 of the four bending plates 330 is the same as the clockwise direction of stirring.

[0040] Comparative Example 1

[0041] The difference between this comparative example and Example 1 is that the baffle plate has no through hole 311, and the others are the same.

[0042] Comparative Example 2

[0043] The difference between this comparative example and Example 2 is that the four flow-around plates 320 are uniformly installed in the positive direction, that is, the triangular protrusions 321 of all the installed flow-around plates 320 are inclined upward, and the others are the same.

[0044] Comparative Example 3

[0045] The difference between this comparative example and Example 3 is that the specific installation direction of the baffle plate is that the non-planar branch plate of the four bending plates 330 is the same as the counterclockwise direction of stirring, that is, opposite to the clockwise direction of stirring, and the others are the same.

[0046] The reaction kettles of Examples 1-3 and Comparative Examples 1-3 are used as the reaction kettles of the following process to prepare a quaternary precursor product:

[0047] A mixed salt solution of 2 mol / L nickel sulfate, cobalt sulfate, and manganese sulfate was prepared in 5 L, with a molar ratio of Ni:Co:Mn = 89:5:5. A mixed solution of sodium metaaluminate and ammonia was prepared in 5 L, with a molar ratio of Al:Ni = 1:89, and the concentration of ammonia was 2.4 mol / L. A 4 mol / L sodium hydroxide solution was prepared in 5 L, and a 0.8 mol / L ammonia solution was prepared in 4 L. The bottom solution was added to the reactor, and the reaction temperature was controlled at 50°C. Argon was introduced into the reactor, and after the air in the reactor was exhausted (0.5 Mpa gas volume), the gas flow rate was adjusted from 10 ml / min to 0.2 ml / min. The sodium hydroxide solution was pumped into the reactor at a feed rate of 1.7 ml / min by a peristaltic pump, and the pH of the bottom solution was adjusted to 11.0 ± 0.2. The mixed salt solution and the aluminum salt ammonia solution were simultaneously fed at a feed rate of 1.7 ml / min, and the stirring speed was set to 800 rpm. The reaction pH was controlled between 11.0 ± 0.1, and the co-precipitation reaction was carried out. After 36 h of reaction, 15 L of reactor liquid was collected, washed with water, suction filtered, and dried at 120°C for 12 h to obtain a four-element precursor material with controllable crystal faces.

[0048] The XRD patterns of the four-element precursor materials obtained by reaction in each reactor are shown in Figure 4 The exposure ratios of the crystal faces of each four-element precursor material are shown in Table 1. The four-element precursor materials obtained by reaction in each reactor were mixed with lithium (lithium hydroxide monohydrate) at a molar ratio of 1.03, and calcined at 760°C for 15 h to obtain a highly ordered four-element layered cathode material. The XRD of the four-element layered cathode material is shown in Figure 5 The exposure ratios of the crystal faces of each four-element layered cathode material are shown in Table 1.

[0049]

[0050] Table 1

[0051] In summary, the application improves the flow field inside the kettle body 100 and enhances the mixing effect under the stirring of the stirring assembly 200 through the detachable installation of the flow-through plate 310 or the flow-around plate 320 or the bent plate 330 inside the kettle body 100, and under the condition that the conventional hydrogen oxide coprecipitation synthesis process and parameter conditions remain unchanged, the precursor particles can be realized to grow along the preferred crystal surface (101) first, and the (101) diffraction peak intensity is the highest. At the same time, through the adjustment of the turbulent energy and shear stress of the area near the baffle by the three different types of baffles (flow-through plate 310, flow-around plate 320 or bent plate 330), the exposure ratio of the (001) crystal surface can be controlled, so that the diffraction peak intensity ratio I(001) / I(101) can be controlled in the range of 0.75-0.91, thereby the type of baffle can be selected as needed according to the requirements. The use of the reaction kettle of the application can realize the adjustment of the exposure ratio of the (001) crystal surface while ensuring the full growth of the preferred crystal surface without the need to change the existing production line, and then the layered positive electrode material with controllable (003) crystal surface can be obtained.

[0052] The above examples are only used to illustrate the technical solutions of the application and are not limited. Although the application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the application can be modified or replaced equivalently without departing from the purpose and scope of the application, and all should be covered in the scope of the claims of the application. The technical, shape and structure parts not described in detail in the application are well-known technologies.

Claims

1. A reaction kettle for realizing controllable growth of high-nickel precursor crystal face, characterized in that, The utility model relates to a kettle body, a stirring assembly for stirring the material inside the kettle body, four baffles which are equidistantly detachably installed on the inner wall of the kettle body, the center line of the baffle being parallel to the vertical center line of the kettle body, the baffle being selected from any one of a through-flow baffle, a flow-around baffle and a bent baffle, the through-flow baffle, the flow-around baffle and the bent baffle each comprising a straight plate which is installed along the radial direction of the kettle body with one side abutting against the inner wall of the kettle body, the straight plate of the through-flow baffle having at least one through hole, the straight plate of the flow-around baffle being provided with triangular protrusions which are arranged on the side of the flow-around baffle facing the stirring assembly, the straight plate of the bent baffle being connected with a branch plate, the length of the straight plate of the bent baffle being the same as the length of the branch plate, and the end of the straight plate of the bent baffle away from the inner wall of the kettle body being connected with the branch plate, the straight plate having two mounting holes, the detachable installation of the straight plate on the inner wall of the kettle body being realized by screwing bolts in the mounting holes, the through hole of the through-flow baffle having five through holes which are equidistantly distributed on the straight plate of the through-flow baffle, the triangular protrusions being right-angled triangular protrusions, the triangular protrusions having upper and lower two, one right-angled face of the triangular protrusions being at a 45° angle with the side face of the straight plate of the flow-around baffle, two flow-around baffles being installed on the inner wall of the kettle body in the forward direction, and the other two flow-around baffles being installed on the inner wall of the kettle body in the reverse direction, the triangular protrusions of the flow-around baffles installed in the forward direction being inclined upward, and the triangular protrusions of the flow-around baffles installed in the reverse direction being inclined downward, the straight plate of the bent baffle being connected with the branch plate through a circular arc transition, and the included angle between the straight plate and the branch plate of the bent baffle being 135°. ​ ​ ​ ​ ​ ​ ​ 2. The reactor for realizing controllable growth of nickel-rich precursor crystal face according to claim 1, characterized in that, ​ 3. The reactor for realizing controllable growth of crystal faces of high nickel precursors according to claim 2, characterized in that, ​ 4. The reactor for realizing controllable growth of nickel-rich precursor crystal face according to claim 2, characterized in that, ​ 5. The reactor for realizing controllable growth of nickel-rich precursor crystal face according to claim 4, characterized in that, ​ 6. The reactor for realizing controllable growth of nickel-rich precursor crystal face according to claim 5, characterized in that, ​ 7. The reactor for realizing controllable growth of nickel-rich precursor crystal face according to claim 2, characterized in that, ​ 8. The reactor for realizing controllable growth of nickel-rich precursor crystal face according to claim 7, characterized in that, ​

Images