Preparation method of lithium battery positive electrode material

Abstract

This invention provides a sagger for sintering lithium battery cathode materials and its preparation method, belonging to the field of lithium battery technology. It includes a frame for holding lithium battery cathode materials, with air guide columns evenly distributed within the frame; a lifting tray for supporting the lithium battery cathode materials, the lifting tray being disposed inside the frame and having through holes that mate with the air guide columns; and a lifting mechanism disposed below the frame for driving the lifting tray to move up and down, the frame having guide openings that mate with the lifting mechanism. This invention redesigns the overall structure of the sagger, making it very convenient to place and remove the sagger from the calcining furnace, eliminating unnecessary cables or air guide pipes and improving convenience. The lithium battery cathode materials are sintered more uniformly, and the sintering speed is increased, thereby improving production efficiency and better meeting industrial production needs. Furthermore, the sintered material is less prone to sticking and is easy to remove.

Description

Technical Field

[0001] This invention relates to the field of lithium battery technology, specifically to a sagger for sintering lithium battery cathode materials and its preparation method. Background Technology

[0002] Lithium batteries are a type of battery that uses lithium metal or lithium alloy as the positive / negative electrode material and a non-aqueous electrolyte solution.

[0003] The advantages of lithium batteries are very obvious, for example:

[0004] 1. High energy density. It has a high energy storage density, reaching 460-600Wh / kg, which is about 6-7 times that of lead-acid batteries;

[0005] 2. Long service life, up to 6 years or more. Batteries with lithium iron phosphate as the positive electrode can be used 10,000 times at 1C (100% DOD) charge and discharge.

[0006] 3. High rated voltage (single cell operating voltage is 3.7V or 3.2V), approximately equal to the series voltage of three nickel-cadmium or nickel-metal hydride rechargeable batteries, making it easy to form a battery power pack; lithium batteries can be adjusted to 3.0V using a new type of lithium battery voltage regulator technology to make them suitable for use in small electrical appliances.

[0007] 4. It has high power handling capacity. The lithium iron phosphate lithium-ion batteries used in electric vehicles can achieve a charge-discharge capacity of 15-30C, which is convenient for high-intensity start-up acceleration.

[0008] 5. The self-discharge rate is very low, which is one of the most outstanding advantages of this battery. It can generally be less than 1% / month, which is less than 1 / 20 of that of nickel-metal hydride batteries.

[0009] 6. Lightweight, weighing approximately 1 / 6 to 1 / 5 of lead-acid products for the same volume.

[0010] The sintering process of lithium battery cathode materials requires loading the cathode material into a special sagger and pushing it into a sintering furnace for sintering. The saggers currently used do not allow sufficient contact between the cathode material and the atmosphere in the sintering furnace, resulting in poor quality or uneven performance of the sintered product. Furthermore, the sintered material adheres to the sagger wall and is difficult to remove, which can easily damage the sagger itself. Summary of the Invention

[0011] In view of this, the present invention provides a sagger for sintering lithium battery cathode materials and its preparation method, which not only ensures uniform sintering of lithium battery cathode materials, but also prevents them from sticking together after sintering and makes them easy to remove.

[0012] To solve the above-mentioned technical problems, the present invention provides a sagger for sintering lithium battery cathode materials and a method for preparing the same, comprising:

[0013] A rack for holding lithium battery cathode materials, wherein air guide columns are evenly distributed within the frame of the rack;

[0014] A lifting tray is used to support the positive electrode material of a lithium battery. The lifting tray is set inside the frame and has through holes that cooperate with the air guide column.

[0015] A lifting mechanism is provided, which is located below the frame and is used to drive the lifting tray to rise and fall. The frame has a guide opening that cooperates with the lifting mechanism.

[0016] By adopting the above technical solution, the lithium battery cathode material is perforated, ensuring uniform heating during firing and significantly accelerating the firing speed. The frame consists of a frame for holding the lithium battery cathode material and legs supporting the frame. Air guide columns are installed inside the frame. After the lithium battery cathode material is fired and shaped, a lifting mechanism lifts the lifting tray, separating the lithium battery cathode material from the air guide columns. Air guide holes are formed on the lithium battery cathode material, and hot air enters through the through-holes on the lifting tray, making the lithium battery cathode material heat more evenly and removing moisture from its interior, accelerating firing and improving production efficiency.

[0017] Furthermore, each of the four corners of the lifting pallet is provided with a connecting plate column, and a mesh plate is movably connected between two adjacent connecting plate columns. A baffle plate is also fixedly installed around the perimeter of the frame, and the mesh plate is located in the gap between the baffle plate and the frame.

[0018] By adopting the above technical solution, the mesh plate rises with the lifting tray, playing a protective role around the lithium battery positive electrode material and preventing lithium battery positive electrode material fragments from falling outside the crucible.

[0019] Furthermore, lifting columns are movably connected to the four corners of the frame, and a first pneumatic cylinder is fixedly connected to the lifting column. A piston rod is fixedly connected to the output end of the first pneumatic cylinder, and the other end of the piston rod is fixedly connected to a fixed seat. The fixed seat is fixedly installed on the top of the connecting plate column, and a gap is reserved between the connecting plate column and the lifting column.

[0020] By adopting the above technical solution, the lithium battery positive electrode material can be prevented from sticking to the mesh plate. Although there is a certain gap between the mesh plate and the lithium battery positive electrode material under normal conditions, the lithium battery positive electrode material may stick to the mesh plate as it expands due to heat. Therefore, by pulling the connecting plate column with the first pneumatic cylinder, the mesh plate is expanded outward to prevent sticking.

[0021] Furthermore, the lifting mechanism includes a second pneumatic cylinder, a cylinder plug is slidably connected inside the second pneumatic cylinder, a piston rod is fixedly connected to the top of the cylinder plug, and the piston rod passes through a guide port and is fixedly connected to the lifting tray.

[0022] Furthermore, both the first and second pneumatic cylinders are filled with liquid.

[0023] Furthermore, the boiling point of the liquid inside the first pneumatic cylinder is greater than the boiling point of the liquid inside the second pneumatic cylinder.

[0024] By adopting the above technical solutions, the equipment failure rate is reduced and the convenience is improved. Due to the high temperature inside the calcining furnace, electric and pneumatic lifting mechanisms are easily damaged by the high temperature and their service life is reduced. By utilizing the principle of liquid high-temperature vaporization and expansion, electric or pneumatic lifting mechanisms can be replaced, which is not only more convenient to use, but also has a longer service life and is less prone to damage.

[0025] A method for preparing a lithium battery cathode material, wherein the method uses a sintering crucible for the lithium battery cathode material, and includes the following steps:

[0026] Feeding: Fill the frame with the well-stirred lithium battery cathode material;

[0027] Firing involves placing a crucible filled with lithium battery cathode material into a calcining furnace for firing.

[0028] During the shaping and opening process, the moisture content of the paste-like lithium battery positive electrode material gradually decreases and solidifies. The liquid in the second pressure cylinder vaporizes and expands, pushing the cylinder plug and piston cylinder upward. The lithium battery positive electrode material separates from the air guide column, and air guide holes are formed on the lithium battery positive electrode material.

[0029] As the heating time increases, the liquid inside the first pressure cylinder expands and drives the receiving plate column to move outward in the normal direction at the four corners through the piston connecting rod, thereby causing the mesh plate to move outward, increasing the gap between the lithium battery positive electrode material and the mesh plate, and preventing the lithium battery positive electrode material from expanding and contacting the mesh plate.

[0030] After the materials are collected and fired, and the crucible and lithium battery positive electrode material are removed after complete cooling.

[0031] Furthermore, after the lithium battery cathode material is filled, the top is smoothed using a scraper.

[0032] By adopting the above technical solution, the problems of long firing time and uneven firing of traditional lithium battery cathode materials are solved. The traditional firing method results in slow evaporation of internal moisture in lithium battery cathode materials, leading to long firing time, reduced efficiency and yield, and difficulty in meeting production needs. This preparation method improves the internal heating and moisture evaporation rate of lithium battery cathode materials by opening pores in the lithium battery cathode materials, thereby accelerating the firing speed.

[0033] The beneficial effects of the above-described technical solution of the present invention are as follows:

[0034] When using it, fill the frame with the well-stirred lithium battery positive electrode material. After filling, use a scraper to smooth the top of the lithium battery positive electrode material, and then put the sagger into the calcining furnace for firing.

[0035] After a period of firing, the moisture on the outer layer of the lithium battery positive electrode material is basically evaporated, and the lithium battery positive electrode material solidifies and takes shape. At this time, the solution inside the second pressure cylinder has been heated and reached the boiling point, and gradually begins to vaporize. After the solution vaporizes, its volume expands and the air pressure increases, which drives the cylinder plug and piston rod to rise. The lifting tray drives the solidified lithium battery positive electrode material, the first pressure cylinder, and the lifting column to move upward together. After rising, due to the setting of the air guide column, the position of the air guide column of the lithium battery positive electrode material forms an air guide hole, which makes the inside of the lithium battery positive electrode material heat evenly. The air guide hole also accelerates the evaporation of moisture and speeds up the calcination speed.

[0036] As heating continues, the positive electrode material of the lithium battery gradually begins to expand, and the solution in the first pressure cylinder also reaches its boiling point and vaporizes. The first pressure cylinder pulls the connecting plate column, thereby causing the mesh plate to expand outward and preventing adhesion.

[0037] This invention not only improves the firing speed of lithium battery cathode materials, but also simplifies the operation of the sagger, making it very easy to remove the lithium battery cathode materials. Attached Figure Description

[0038] Figure 1 This is a perspective view of the sagger used for sintering the positive electrode material of the lithium battery according to the present invention;

[0039] Figure 2 for Figure 1 Enlarged view of part A;

[0040] Figure 3 for Figure 1 Enlarged view of part B;

[0041] Figure 4 This is a perspective view of the lifting tray of the sagger used for sintering lithium battery cathode material according to the present invention after it has been raised.

[0042] Figure 5 This is a bottom view of the sagger used for sintering the positive electrode material of the lithium battery according to the present invention.

[0043] Figure 6 This is a partial cross-sectional view of the sagger used for sintering the positive electrode material of the lithium battery according to the present invention;

[0044] Figure 7 This is a schematic diagram of the lifting tray of the sagger used for sintering lithium battery cathode material according to the present invention after it has been raised.

[0045] Figure 8 This is a partial cross-sectional view of the lifting tray of the sagger used for sintering lithium battery cathode materials according to the present invention after it has been raised.

[0046] Figure 9 This is a reference diagram showing the usage state of the sagger used for sintering the lithium battery cathode material according to the present invention.

[0047] 1. Support leg; 2. Baffle plate; 3. Frame; 4. Air guide column; 5. Mesh plate; 6. Connecting plate column; 7. Fixed seat; 8. Piston connecting rod; 9. First pneumatic cylinder; 10. Lifting column; 11. Second pneumatic cylinder body; 12. Guide port; 13. Cylinder plug; 14. Lifting tray; 15. Pneumatic cylinder fixing rod; 16. Piston rod. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will be described in conjunction with the accompanying drawings of the embodiments of the present invention. Figure 1-9 The technical solutions of the embodiments of the present invention will be clearly and completely described herein. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0049] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. In addition, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0050] like Figure 1-9As shown: A sagger for sintering lithium battery cathode materials and its preparation method, comprising:

[0051] The frame is used to place the positive electrode material of the lithium battery. The frame 3 of the frame is evenly distributed with air guide columns 4.

[0052] The lifting tray 14 is used to support the positive electrode material of the lithium battery. The lifting tray 14 is set inside the frame 3 and has through holes that cooperate with the air guide column 4.

[0053] The lifting mechanism is located below the frame and is used to drive the lifting tray 14 to rise and fall. The frame 3 has a guide port 12 that cooperates with the lifting mechanism.

[0054] By adopting the above technical solution, the lithium battery cathode material is perforated to ensure uniform heating during firing and significantly accelerate the firing speed. The frame consists of a frame 3 for holding the lithium battery cathode material and legs 1 supporting the frame 3. Air guide columns 4 are installed inside the frame 3. After the lithium battery cathode material is fired and shaped, the lifting mechanism lifts the lifting tray 14, separating the lithium battery cathode material from the air guide column 4. Air guide holes are formed on the lithium battery cathode material, and hot air enters the air guide holes of the lithium battery cathode material through the through holes on the lifting tray 14, making the lithium battery cathode material heat more evenly and removing moisture from inside the lithium battery cathode material, accelerating firing and improving production efficiency.

[0055] According to one embodiment of the present invention, such as Figure 1-9 As shown,

[0056] In this embodiment, the four corners of the lifting tray 14 are provided with receiving plate posts 6, and the two sides of the receiving plate posts 6 are provided with grooves that cooperate with the mesh plate 5, so as to achieve the purpose of movably connecting the mesh plate 5 and the receiving plate posts 6. The mesh plate 5 is movably connected between two adjacent receiving plate posts 6. The frame 3 is also fixedly installed with baffle plates 2 around its perimeter. The baffle plates 2 are smooth so as to reduce the adhesion of lithium battery positive electrode material and ensure that there is only a very small amount of lithium battery positive electrode material residue on the baffle plates 2. The residue attached to the baffle plates 2 will be wiped off during the lifting of the lifting tray 14, without the need for manual scraping, which improves convenience. The mesh plate 5 is located in the gap between the baffle plates 2 and the frame 3.

[0057] By adopting the above technical solution, the mesh plate 5 rises with the lifting tray 14, playing a protective role around the lithium battery positive electrode material and preventing lithium battery positive electrode material fragments from falling to the outside of the crucible.

[0058] The four corners of the frame 3 are movably connected with lifting columns 10. A first pneumatic cylinder 9 is fixedly connected to the lifting column 10. A piston rod 8 is fixedly connected to the output end of the first pneumatic cylinder 9. The other end of the piston rod 8 is fixedly connected to the fixed seat 7. The fixed seat 7 is fixedly installed on the top of the connecting plate column 6. A gap is reserved between the connecting plate column 6 and the lifting column 10.

[0059] By adopting the above technical solution, the lithium battery positive electrode material can be prevented from sticking to the mesh plate 5. Although there is a certain gap between the mesh plate 5 and the lithium battery positive electrode material under normal conditions, the lithium battery positive electrode material may stick to the mesh plate 5 as it expands due to heat. Therefore, the first pneumatic cylinder 9 pulls the connecting plate column 6, thereby causing the mesh plate 5 to expand outward and preventing sticking.

[0060] According to another embodiment of the invention, such as Figure 1-9 As shown,

[0061] In this embodiment, the lifting mechanism includes a second pneumatic cylinder, which is fixedly connected to the frame via a cylinder fixing rod. A cylinder plug 13 is slidably connected inside the second pneumatic cylinder, and a piston rod 16 is fixedly connected to the top of the cylinder plug 13. The piston rod 16 passes through the guide port 12 and is fixedly connected to the lifting tray 14.

[0062] Both the first and second pneumatic cylinders are filled with liquid.

[0063] The boiling point of the liquid inside the first pressure cylinder 9 is higher than that of the liquid inside the second pressure cylinder. In this embodiment, the liquid inside the second pressure cylinder is kerosene, and the liquid inside the first pressure cylinder 9 is linseed oil.

[0064] By adopting the above technical solutions, the equipment failure rate is reduced and the convenience is improved. Due to the high temperature inside the calcining furnace, electric and pneumatic lifting mechanisms are easily damaged by the high temperature and their service life is reduced. By utilizing the principle of liquid high-temperature vaporization and expansion, electric or pneumatic lifting mechanisms can be replaced, which is not only more convenient to use, but also has a longer service life and is less prone to damage.

[0065] In other embodiments, a high-temperature resistant electric or pneumatic lifting mechanism may also be used.

[0066] A method for preparing a lithium battery cathode material, the method comprising the above-mentioned sintering crucible for the lithium battery cathode material, includes the following steps:

[0067] Feeding: Fill the frame 3 with the well-stirred lithium battery cathode material;

[0068] Firing involves placing a crucible filled with lithium battery cathode material into a calcining furnace for firing.

[0069] During the firing process, the moisture content of the paste-like lithium battery positive electrode material gradually decreases and solidifies. The liquid in the second pressure cylinder vaporizes and expands, pushing the cylinder plug 13 and piston cylinder upward. The lithium battery positive electrode material separates from the air guide column 4, and air guide holes are formed on the lithium battery positive electrode material.

[0070] As the heating time increases, the liquid inside the first pneumatic cylinder 9 expands and drives the receiving plate column 6 to move outward in the normal direction at the four corners through the piston connecting rod 8. This causes the mesh plate 5 to move outward, increasing the gap between the lithium battery positive electrode material and the mesh plate 5, thus preventing the lithium battery positive electrode material from expanding and contacting the mesh plate 5.

[0071] After the materials are collected and fired, and the crucible and lithium battery positive electrode material are removed after complete cooling.

[0072] After the lithium battery cathode material is filled, the top is smoothed with a scraper. Smoothing serves two purposes: first, to maintain the regular shape of the finished lithium battery cathode material, and second, to prevent the accumulation of lithium battery cathode material on the top surface of the air guide column, which would affect the normal rise of the lithium battery cathode material.

[0073] By adopting the above technical solution, the problems of long firing time and uneven firing of traditional lithium battery cathode materials are solved. The traditional firing method results in slow evaporation of internal moisture in lithium battery cathode materials, leading to long firing time, reduced efficiency and yield, and difficulty in meeting production needs. This preparation method improves the internal heating and moisture evaporation rate of lithium battery cathode materials by opening pores in the lithium battery cathode materials, thereby accelerating the firing speed.

[0074] The working method (or working principle) of this invention:

[0075] When using, fill the frame 3 with the well-stirred lithium battery positive electrode material. After filling, use a scraper to smooth the top of the lithium battery positive electrode material, and then put the sagger into the calcining furnace for firing.

[0076] After a period of firing, the moisture on the outer layer of the lithium battery positive electrode material is basically evaporated, and the lithium battery positive electrode material solidifies and takes shape. At this time, the solution inside the second pressure cylinder has been heated and reached the boiling point, and gradually begins to vaporize. After the solution vaporizes, the volume expands and the air pressure increases, which drives the cylinder plug 13 and piston rod 16 to rise. The lifting tray 14 drives the solidified lithium battery positive electrode material, the first pressure cylinder 9 and the lifting column 10 to move upward together. After rising, due to the setting of the air guide column 4, the position of the air guide column 4 of the lithium battery positive electrode material forms an air guide hole, so that the inside of the lithium battery positive electrode material is heated evenly, and the air guide hole will also accelerate the evaporation of moisture and speed up the calcination speed.

[0077] As heating continues, the positive electrode material of the lithium battery gradually begins to expand, and the solution in the first pressure cylinder 9 also reaches the boiling point and vaporizes. The first pressure cylinder 9 pulls the connecting plate column 6, thereby causing the mesh plate 5 to expand outward and prevent adhesion.

[0078] This invention not only improves the firing speed of lithium battery cathode materials, but also simplifies the operation of the sagger, making it very easy to remove the lithium battery cathode materials.

[0079] In this invention, unless otherwise explicitly specified and limited, for example, it can be a fixed connection, a detachable connection, or an integral part; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two elements or an interaction between two elements. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0080] The above are preferred embodiments of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principles described in the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a lithium battery cathode material, characterized in that, The preparation method employs a sagger for sintering lithium battery cathode materials, the sagger comprising: A rack is used to place lithium battery positive electrode materials. Air guide columns (4) are evenly distributed inside the frame (3) of the rack. The lifting tray (14) is used to support the positive electrode material of the lithium battery. The lifting tray (14) is set inside the frame (3). The lifting tray (14) has a through hole that cooperates with the air guide column (4). The lifting mechanism is located below the frame and is used to drive the lifting tray (14) to rise and fall. The frame (3) has a guide opening (12) that cooperates with the lifting mechanism. The lifting tray (14) is provided with connecting plate columns (6) at all four corners, and a mesh plate (5) is movably connected between two adjacent connecting plate columns (6). A baffle plate (2) is also fixedly installed around the frame (3). The mesh plate (5) is located in the gap between the baffle plate (2) and the frame (3). The four corners of the frame (3) are movably connected with lifting columns (10), and a first pneumatic cylinder (9) is fixedly connected to the lifting column (10). The output end of the first pneumatic cylinder (9) is fixedly connected to a piston rod (8), and the other end of the piston rod (8) is fixedly connected to a fixed seat (7). The fixed seat (7) is fixedly installed on the top of the connecting plate column (6), and a gap is reserved between the connecting plate column (6) and the lifting column (10). The lifting mechanism includes a second pneumatic cylinder, in which a cylinder plug (13) is slidably connected, and a piston rod (16) is fixedly connected to the top of the cylinder plug (13). The piston rod (16) passes through the guide port (12) and is fixedly connected to the lifting tray (14). Both the first pneumatic cylinder (9) and the second pneumatic cylinder are filled with liquid; The boiling point of the liquid inside the first pneumatic cylinder (9) is greater than the boiling point of the liquid inside the second pneumatic cylinder; The preparation method includes the following steps: Feeding: Fill the frame (3) with the well-stirred lithium battery cathode material; Firing involves placing a crucible filled with lithium battery cathode material into a calcining furnace for firing. During the firing process, the moisture content of the paste-like lithium battery positive electrode material gradually decreases and solidifies. The liquid in the second pressure cylinder vaporizes and expands, pushing the cylinder plug (13) and piston cylinder to rise. The lithium battery positive electrode material separates from the air guide column (4), and air guide holes are formed on the lithium battery positive electrode material. As the heating time increases, the liquid inside the first pressure cylinder (9) expands and drives the receiving plate column (6) to move outward in the normal direction of the four corners through the piston rod (8), thereby causing the mesh plate (5) to move outward, increasing the gap between the lithium battery positive electrode material and the mesh plate (5), and preventing the lithium battery positive electrode material from expanding and contacting the mesh plate (5). After the materials are collected and fired, and the crucible and lithium battery positive electrode material are removed after complete cooling.

2. The method for preparing the lithium battery cathode material as described in claim 1, characterized in that: After the lithium battery positive electrode material is filled, the top is smoothed with a scraper.

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