Spliced graphite sagger for sintering anode and cathode materials of battery

Abstract

The invention relates to the technical field of battery positive and negative electrode material production and preparation devices, in particular to a spliced graphite sagger for sintering battery positive and negative electrode materials, which comprises a bottom plate, a central boss is arranged on the bottom plate, and a bearing position is formed between the periphery and the edge of the bottom plate; the bearing position comprises a column foot bearing position and a side plate bearing position; the column foot is vertically connected with the column foot bearing position, a first side plate connecting position is arranged on one side of the column foot, and a second side plate connecting position is arranged on the other side of the column foot; the side plate comprises a first side plate connecting part and a second side plate connecting part which are symmetrically arranged, the first side plate connecting part is connected with the first side plate connecting position, and the second side plate connecting part is connected with the second side plate connecting position; the bottom of the side plate is vertically connected with the side plate bearing position; after the bottom plate is connected with the column feet and the side plates, a box body with a cavity is formed. The device is simple in structure, convenient to splice and high in firmness, parts can be directly replaced under the condition that the parts are damaged, and the maintenance cost can be effectively reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of production and preparation devices for battery positive and negative electrode materials, and particularly to a spliced graphite crucible for sintering battery positive and negative electrode materials. Background Art

[0002] A graphite crucible is a high-temperature resistant container mainly made of high-purity artificial graphite as the main raw material. The raw material is prepared through processes such as kneading, molding, isostatic pressing, roasting, impregnation, and graphitization, and then machined mechanically. It can withstand extreme temperatures above 2000°C, can quickly and evenly transfer heat, and avoid local overheating; it can also resist the erosion of corrosive media such as acids, alkalis, and molten metals. Therefore, it is widely used in the field of new energy lithium battery materials. For example, in the production of lithium batteries, the graphite crucible mainly serves as a high-temperature resistant and high-thermal conductivity sintering container, used to carry the positive / negative electrode materials and ensure their structural stability and chemical purity during high-temperature treatment, thereby improving the battery capacity, cycle life, and safety.

[0003] There are two traditional preparation methods for graphite crucibles. One is the mechanical machining and excavation process, which uses artificial graphite blocks as raw materials and adopts the excavation and milling processing method. There are problems such as extremely low raw material utilization rate (<20%), a large amount of waste generated, and high recycling costs; at the same time, the supply of artificial graphite blocks is limited and the processing cycle is long, resulting in serious production capacity shortages, and a large amount of dust particles are generated during the machining process, and the environmental protection treatment cost is extremely high. The other is the molding + curing process by die pressing, which relies on high-pressure molds and heating equipment. The initial equipment investment is high and the product yield is low, only 50%-60%; in addition, due to the difference in thermal expansion coefficients between graphite powder and petroleum coke, the local densities are inconsistent under die pressing, and the thermal stress is concentrated in the material after die pressing, the flexural strength decreases by 30%-50%, and the porosity > 20%, resulting in brittle products, poor thermal shock stability, and the service life being less than 1 / 5 of the traditional process.

[0004] In view of the above defects, the Chinese invention patent with the publication number CN114508943B discloses a combined graphite crucible and its forming method. The combined graphite crucible includes a bottom plate, a plurality of side plates, a plurality of graphite square columns, and carbon fiber screws. The side plates are vertically arranged on the bottom plate along the four sides of the bottom plate and enclose a box structure with a cavity with the bottom plate. The graphite square columns are respectively arranged along the joints of the side plates and the bottom plate, and the side plates and the side plates. Connection holes are opened on the graphite square columns, the bottom plate, and the side plates, and the bottom plate, the side plates, and the graphite square columns are fixed by the carbon fiber screws in cooperation with the connection holes; a carbonized layer covers the surface of the carbon fiber screws, or a carbonized layer or carbonized particles are filled between the carbon fiber screws and the inner wall of the connection holes. It is pointed out that this solution solves the problems of high cost, complex processing, stress concentration, and mechanical defects of graphite crucibles in the prior art.

[0005] Although the graphite square columns arranged along the seams in the above - mentioned solution can play a role in dispersing stress, that is, the connection structure of the graphite square columns and carbon fiber screws at the joints described in the disclosed solution can, without increasing the thickness of the side plates, completely solve the problems of brittle fracture and cracking during use at the splicing parts of the side plates; furthermore, setting the graphite square columns at the seams can effectively prevent the leakage of materials at the seams. However, it has been found in practice that although the graphite square columns and the side plates / floor plates are both made of graphite, if the material batches or densities are different, the expansion rates may vary significantly at high temperatures (600 - 1400°C), which can lead to stress cracking; that is, shear stress is generated at the seams due to uneven expansion, resulting in cracking at the connection between the graphite square columns and the side plates. After multiple thermal cycles, the carbon fiber screws may experience thread wear due to repeated stress, exacerbating the risk of loosening. On the one hand, in this solution, the graphite square columns only cover the surface of the seams and cannot completely fill the internal micro - gaps, easily causing the failure of the seam sealing and material leakage. For example, when sintering lithium iron phosphate powder, powders with a particle size of about 10 - 20μm may penetrate into the seams from the edges of the graphite square columns; and at high temperatures, the shrinkage of the graphite material causes the gap between the square columns and the side plates to expand (for example, when the difference in the coefficient of thermal expansion is 0.5×10 -6 / °C, a 500 - mm - long seam generates a 0.2 - mm gap at 800°C). On the other hand, the graphite square columns need to be strictly aligned with the connection holes of the side plates / floor plates (the tolerance needs to be ≤0.1 mm), otherwise, forcing the carbon fiber screws to be screwed in will damage the threads; especially when the processing error of the bearing platform of the floor plate exceeds 0.3 mm, it will cause the side plates to tilt, resulting in the graphite square columns not being able to fit the seams; in addition, when replacing the damaged side plates, the graphite square columns need to remove the screws, and repeated operations may cause the connection holes to be reamed (for example, the diameter of an M6 thread hole increases by 0.2 mm after 5 disassembly and assembly operations), resulting in dependence on installation accuracy and difficulty in maintenance.

[0006] On the other hand, in the disclosed solution, the side plates are clamped by male - female joints, but at high temperatures, the graphite material may deform due to thermal expansion, resulting in misalignment of the joints; further causing material leakage at the seams, affecting the sintering quality of the positive electrode material, and it is difficult to repeat disassembly and assembly after the joints are deformed, reducing the reuse rate of the crucible. For the corner wrap, if it is added later, if the bottom corner wrap is not firmly connected to the side plates / floor plates, it may fall off due to thermal stress or mechanical shock; and if it is formed simultaneously with the side plates, the connection part of the corner wrap will become a new stress concentration point, accelerating the structural damage.

[0007] Therefore, there is an urgent need for a new technical solution to solve the above - mentioned technical problems. Summary of the Invention

[0008] The object of the present invention is to overcome the above problems of the prior art, and provides a spliced graphite crucible for sintering positive and negative electrode materials of a battery, which is used to solve the technical problems existing in the connection structure of graphite square columns and carbon fiber screws at the splicing part of the existing spliced graphite crucible, such as stress cracking caused by differences in thermal expansion coefficients, the graphite square columns only cover the surface of the seam and cannot completely fill the internal micro-gaps, resulting in the failure of the seam sealing and material leakage, as well as the dependence on installation accuracy and the difficulty of maintenance.

[0009] The above object is achieved by the following technical solutions: A spliced graphite crucible for sintering positive and negative electrode materials of a battery, comprising: A bottom plate, on which a central boss is provided, and a closed-loop receiving position is formed between the periphery of the central boss and the edge of the bottom plate; the receiving position includes a column foot receiving position at the corner and a side plate receiving position between adjacent column foot receiving positions; column feet, the column feet are perpendicularly connected to the column foot receiving positions, a first side plate connecting position is provided on one side of the column feet, and a second side plate connecting position is provided on the other side; side plates, the side plates include symmetrically arranged first side plate connecting parts and second side plate connecting parts, the first side plate connecting part is connected to the first side plate connecting position of the adjacent column foot, and the second side plate connecting part is connected to the second side plate connecting position of the adjacent column foot; the bottom of the side plate is perpendicularly connected to the side plate receiving position; after the bottom plate is connected to each column foot and each side plate, a box body with a cavity is formed.

[0010] Furthermore, the bottom plate and the column feet, the bottom plate and the side plates, and the side plates and the column feet are connected by carbon fiber screws.

[0011] Furthermore, the column feet include a first column foot right-angled side and a second column foot right-angled side that are perpendicular to each other, and a first side plate limiting clamping groove and a second side plate limiting clamping groove for limiting and clamping the side plates are respectively provided on the first column foot right-angled side and the second column foot right-angled side; the joint surface of the first side limiting clamping groove and the inner wall of the side plate serves as the first side plate connecting position, and the joint surface of the second side limiting clamping groove and the inner wall of the side plate serves as the second side plate connecting position.

[0012] Furthermore, the side plates further include a retaining strip provided on the inner wall of the bottom, and both ends of the retaining strip are limited and clamped by the outer sides of 2 adjacent column feet.

[0013] Furthermore, the thickness of the side plate is equal to the depth of the first column foot right-angled side and the second column foot right-angled side, the thickness of the retaining strip is equal to the thickness of the outer sides of the first side plate connecting position and the second side plate connecting position; the thickness of the side plate is equal to the thickness of the retaining strip.

[0014] Furthermore, it further includes a partition assembly, which is arranged in the cavity and divides the cavity into several independent chambers.

[0015] Furthermore, the partition assembly includes a first insertion plate and a second insertion plate that can be inserted into each other, and slots are provided at the axial positions of the 4 strip-shaped blocks; a first insertion plate slot with an upward opening is provided at the axial position of the first insertion plate, and a second insertion plate slot with a downward opening is provided at the axial position of the second insertion plate. The first insertion plate slot and the second insertion plate slot are perpendicularly inserted into each other to form a cross shape; both ends of the first insertion plate are respectively inserted into the slots on the 2 strip-shaped blocks corresponding to it; both ends of the second insertion plate are respectively inserted into the slots on the 2 strip-shaped blocks corresponding to it.

[0016] Furthermore, a right-angled corner wrap that protrudes outward is also provided on the outer side of the bottom of the column foot. Correspondingly, a corner wrap receiving position corresponding to the position of the right-angled corner wrap is provided on the outer edge of the column foot receiving position.

[0017] Furthermore, a stacking limit boss corresponding to the position of the central boss is also provided at the bottom of the bottom plate. A closed-loop stacking position is formed between the periphery of the stacking limit boss and the bottom edge of the bottom plate, which is used for stacking and limiting with the top of the graphite crucible located below to ensure stable stacking.

[0018] Furthermore, a side plate groove is also provided between the first side plate connection part and the second side plate connection part of the side plate.

[0019] For the spliced graphite crucible for sintering positive and negative electrode materials of the battery provided by the present invention, adjacent side plates use the column foot as a connection medium, avoiding the problem that direct connection of side plates is likely to cause cracking and deformation at the splicing position, effectively increasing the structural strength and stability; through the specific connection form of the column foot and the side plate, the firmness of the spliced graphite crucible is realized, which is firmer than the traditional form of direct screw connection and can effectively avoid stress cracking caused by differences in thermal expansion coefficients; since there is no direct horizontal or longitudinal splicing seam between the connection parts of each component and the cavity, the seam tightness can be improved to prevent material leakage. This spliced graphite crucible not only has a simple structure, few core components and the same specifications, such as using the same specifications of column feet and the same specifications of side plates for a graphite crucible, so it can greatly improve the production efficiency of the device. At the same time, the splicing is simple, the firmness is high, and in the case of component damage, it can be directly replaced, which can effectively reduce the maintenance cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic structural diagram of the first perspective of the spliced graphite crucible for sintering positive and negative electrode materials of the battery of the present invention; Figure 2Second perspective structural diagram of the spliced graphite crucible for sintering the positive and negative electrode materials of the battery according to the present invention; Figure 3 Exploded view of the spliced graphite crucible for sintering the positive and negative electrode materials of the battery according to the present invention; Figure 4 Structural diagram of the spliced graphite crucible with a partition assembly for sintering the positive and negative electrode materials of the battery according to the present invention; Figure 5 Exploded view of the spliced graphite crucible with a partition assembly for sintering the positive and negative electrode materials of the battery according to the present invention; Figure 6 Structural diagram of the bottom plate of the spliced graphite crucible for sintering the positive and negative electrode materials of the battery according to the present invention; Figure 7 Structural diagram of the middle partition assembly of the spliced graphite crucible for sintering the positive and negative electrode materials of the battery according to the present invention; Figure 8 Structural diagram of the middle column foot of the spliced graphite crucible for sintering the positive and negative electrode materials of the battery according to the present invention; Figure 9 Structural diagram of the middle side plate of the spliced graphite crucible for sintering the positive and negative electrode materials of the battery according to the present invention; Figure 10 Schematic diagram of the stacked placement of the spliced graphite crucible for sintering the positive and negative electrode materials of the battery according to the present invention; Figure 11 Cross-sectional view of the stacked placement of the spliced graphite crucible for sintering the positive and negative electrode materials of the battery according to the present invention.

[0021] Illustration marks: 1 - bottom plate, 101 - central boss, 102 - receiving position, 103 - column foot receiving position, 104 - side plate receiving position, 105 - corner receiving position, 106 - stacking limit boss, 107 - stacking position; 2 - column foot, 201 - first side plate connection position, 202 - second side plate connection position, 203 - first column foot right angle side, 204 - second column foot right angle side, 205 - first side limit clamping groove, 206 - second side limit clamping groove, 207 - right angle corner; 3 - side plate, 301 - first side plate connection part, 302 - second side plate connection part, 303 - side plate groove; 4 - cavity, 401 - independent chamber; 5 - carbon fiber screw; 6 - screw hole; 7 - bar, 701 - slot; 8 - partition assembly, 801 - first insertion plate, 802 - second insertion plate, 803 - first insertion plate slot, 804 - second insertion plate slot. Detailed implementation mode

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0023] As Figures 1 to 9 shown, this solution provides a spliced graphite crucible for sintering positive and negative electrode materials of batteries, which is suitable for sintering positive / negative electrode materials of batteries, and includes: A bottom plate 1, on which a central boss 101 is provided, and a closed-loop receiving position 102 is formed between the periphery of the central boss 101 and the edge of the bottom plate 1; the receiving position 102 includes a column foot receiving position 103 at the corner and a side plate receiving position 104 between adjacent column foot receiving positions 103; Column feet 2, which are perpendicularly connected to the column foot receiving positions 103, with a first side plate connection position 201 provided on one side of the column feet 2 and a second side plate connection position 202 provided on the other side; Side plates 3, which include symmetrically arranged first side plate connection parts 301 and second side plate connection parts 302, the first side plate connection part 301 is connected to the first side plate connection position 201 of the column foot 2 at the adjacent position, and the second side plate connection part 302 is connected to the second side plate connection position 202 of the column foot 2 at the adjacent position; the bottom of the side plate 3 is perpendicularly connected to the side plate receiving position 104; After the bottom plate 1 is connected to each column foot 2 and each side plate 3, a box body with a cavity 4 is formed.

[0024] Compared with the traditional mutual contact connection between side plates 3, such as a mother-daughter buckle or a spliced snap connection, in this embodiment, column feet 2 with a thickness greater than that of the side plates 3 are used as the connection medium between adjacent side plates 3, that is, the same column foot 2 is used to facilitate the connection of two side plates 3. The implementation method is as follows: the second side plate connection part 302 of one side plate 3 is connected to the second side plate connection position 202 of this column foot 2, and the first side plate connection part 301 of the other side plate 3 is connected to the first side plate connection position 201 of this column foot 2. At the same time, the bottoms of the 2 side plates 3 are respectively perpendicularly connected to the side plate receiving positions 104 below them.

[0025] Under this structure, even if the graphite material may deform due to thermal expansion at high temperatures, due to the strong support of the column feet 2, the deformation at the connection between the side plates 3 and the column feet will not be caused, and thus the leakage of materials at the joint will not occur, affecting the sintering quality of the positive electrode materials.

[0026] It should be noted that the setting of the central boss 101 not only increases the thickness of the bottom plate 1, enabling it to well support the loaded battery anode / cathode materials and not deform especially in high-temperature environments, but also prompts a closed-loop receiving position 102 to be formed between the periphery of the central boss 101 and the edge of the bottom plate 1, which has a vertical right-angle inner wall. This inner wall can effectively limit the inner sides of each column foot 2 and the side plate 3 installed on the receiving position, and can ensure that it forms a stable perpendicularity between the receiving positions, ensuring that the box body with a cavity 4 formed after connection does not deform under normal conditions or in high-temperature working environments.

[0027] As an embodiment of this solution, the bottom plate 1 is square and is connected by 4 column feet 2 and 4 side plates 3 to form a square box body. A square can ensure that the strengths of all parts are consistent, the stresses and temperature conduction during work are consistent, and it can provide a better sintering effect for the battery anode / cathode materials.

[0028] In this embodiment, the bottom plate 1 and the column foot 2, the bottom plate 1 and the side plate 3, and the side plate 3 and the column foot 2 are connected by carbon fiber screws 5 to enhance the firmness.

[0029] In this embodiment, the material of the graphite crucible is graphite material or carbon fiber and composite materials, and the graphite materials include: Isostatic graphite: Prepared by the isostatic pressing forming process, it has isotropy, high density (above 1.78 g / cm³) and fine crystal structure (5 - 20 μm), and is suitable for precision scenarios such as nuclear reactor neutron moderators and high-temperature molds.

[0030] High-purity graphite: The carbon content is ≥99.9%, and impurities are removed by flotation, high-temperature purification or acid-base methods, and it is used in high-tech fields such as semiconductor wafers, nuclear protection materials and lithium battery anodes.

[0031] Medium-coarse graphite: The particle size is 0.5 - 2.0 mm, and the density is 1.55 - 1.75 kg / m³. It belongs to coarse-structure graphite and is mainly used in industrial scenarios such as metallurgical electrodes and refractory materials.

[0032] The carbon fiber and composite materials among them include: Carbon fiber: Based on high-strength carbon fiber as the matrix, it is treated by high-temperature graphitization, has the characteristics of light weight and high strength, and corrosion resistance, and is applied in fields such as aerospace and sports equipment.

[0033] Carbon-carbon composite material: A carbon matrix material reinforced by carbon fiber, strengthened by the chemical vapor deposition process, with both low density (1.5 - 1.8 g / cm³) and ultra-high temperature stability (>2000℃), and is used in extreme environments such as aerospace thermal protection and high-speed rail braking systems.

[0034] If the carbon fiber screw 5 is directly used for connection, since the screw made of carbon fiber material often has missing teeth during processing, if the screw with missing teeth is used for direct fixed connection, the connection is likely to be unreliable. Therefore, this solution is optimized as follows: Optimization 1. Elastic thread buffer ring: A high temperature resistant elastic ring such as silicone or fluororubber is embedded in the thread root of the carbon fiber screw. During installation, the elastic ring is compressed and deformed to fill the thread gap and disperse the stress. This solution can be used directly on the screw without additional processing; the elastic material cost is low (such as the unit price of silicone ring is less than 0.1 yuan / piece); in addition, it is compatible with existing screws and installation tools.

[0035] Optimization 2: Self-tapping screw + pre-drilled hole design. The carbon fiber screw is designed to be self-tapping, and the connection hole is pre-drilled with a through hole slightly smaller than the screw diameter (no pre-made thread). The screw cuts itself to form a matching thread during installation. This solution eliminates the thread processing step and avoids the problem of missing teeth. It only needs to adjust the hole size, and the graphite part processing cost remains unchanged. In addition, the self-tapping thread has a high fault tolerance rate, and a slight missing tooth does not affect the tightening.

[0036] Optimization 3: Pre-coat high-temperature resin glue. Pre-coat high-temperature resistant resin glue (such as modified phenolic glue) on the surface of the screw thread. The glue fills the thread gap during installation and forms a mechanical interlock after curing. The glue coating process of this solution is simple (can be sprayed or dipped) and low cost; the curing temperature is consistent with the use temperature of the sagger (200-300℃), and no additional heating is required; in addition, the glue layer can compensate for thread processing errors.

[0037] Optimization 4: Replaceable threaded sleeves. Pre-embed high-temperature resistant plastic threaded sleeves (such as PEEK material) in the graphite connection holes. Carbon fiber screws and threaded sleeves are used together. The threaded sleeves can be replaced separately after being damaged. The threaded sleeves of this solution have low injection molding costs (<2 yuan / piece). When installing, they only need to be pressed in, without the need for professional tools. It can effectively avoid direct friction between the screws and graphite and extend their service life.

[0038] Optimization 5. Secondary curing process After assembly, the screw connection is heated locally (200-300℃), and the secondary curing shrinkage characteristics of the carbon fiber resin matrix are used to automatically lock the thread. This solution is completed directly using the waste heat of the sintering furnace, with zero additional cost; curing shrinkage makes the thread contact tighter and compensates for processing defects.

[0039] Optimization 6. Graphite lubricating coating: A graphite-based lubricating coating with a thickness of 10-20μm is applied to the surface of the screw to reduce the friction resistance during installation and reduce the tooth collapse caused by forced screwing. The spraying process of this solution is simple and the cost is low (<3 yuan / ㎡). The coating is resistant to high temperatures (>800℃) and does not affect the sintering environment. In addition, the lubricity makes the screws easier to screw in, which is especially suitable for parts with missing teeth.

[0040] like Figure 3 ,Figure 5 and Figure 8 As shown in Figure 8 , the column base 2 includes a first column base right-angled side 203 and a second column base right-angled side 204 that are perpendicular to each other. A first side plate limiting clamping groove 205 and a second side plate limiting clamping groove 206 for limiting and clamping the side plate 3 are respectively formed on the first column base right-angled side 203 and the second column base right-angled side 204. The joint surface between the first side limiting clamping groove 205 and the inner wall of the side plate 3 serves as the first side plate connection position 201, and the joint surface between the second side limiting clamping groove 206 and the inner wall of the side plate 3 serves as the second side plate connection position 202.

[0041] As an embodiment of this solution, both the first side limiting clamping groove 205 and the second side limiting clamping groove 206 are right-angled grooves. On two adjacent column bases 2, the first side limiting clamping groove 205 on the left column base 2, the second side limiting clamping groove 206 on the right column base 2, and the side plate receiving position 104 on the bottom plate 1 corresponding between the two column bases 2 form a side plate installation space. After the side plate 3 is installed, it is horizontal with the outer surface of the column base 2.

[0042] This structure can ensure that the side plate is completely embedded between the two side limiting clamping grooves on the left and right, and thus it is difficult to deform in the subsequent high-temperature environment, ensuring the stability of the box body.

[0043] As a connection solution between the side plate 3 and the column base 2, in this embodiment, a number of screw holes 6 through which the carbon fiber screw 5 can pass are symmetrically formed on the first side plate connection portion 301 and the second side plate connection portion 302 of the side plate. The side plate 3 is pre-connected to the limiting clamping grooves on the two column bases, and then the carbon fiber screw 5 is pushed in from the outside of the screw hole 6, and after passing through the screw hole 5, it is connected to the first side plate connection position 201 or the second side plate connection position 202.

[0044] As a connection solution between the side plate and the bottom plate 1, in this embodiment, a number of screw holes 6 through which the carbon fiber screw 5 can pass are formed on the side plate receiving position 104 of the bottom plate 1. The bottom of the side plate 3 is pre-connected perpendicularly to the connecting side plate receiving position 104, and then the carbon fiber screw 5 is pushed in from the outside of the screw hole 6, and after passing through the screw hole 6, it is connected to the bottom of the bottom plate 1.

[0045] Through the above operations, the splicing and assembly of the side plate 3 in this solution are realized.

[0046] For the connection between the column base 2 and the bottom plate 1, screw holes 6 through which the carbon fiber screws 5 can penetrate are pre-opened on the column base receiving position 103 of the bottom plate 1. The bottom of the column base 2 is vertically connected to the column base receiving position 103 in advance, and then the carbon fiber screws 5 are pushed in from the outside of the screw holes 6 and connected to the bottom of the column base 2 after passing through the screw holes 5, so as to fix the column base 2 and the bottom plate 1.

[0047] In this embodiment, since the side plate 3 is located outside the first side plate limiting clamping groove 205 and the second side plate limiting clamping groove 206, the first side plate connection position 201 and the second side plate connection position 202 on the column base 2 can well protect the connection part of the side plate 3. Especially when loading materials in the cavity and performing high-temperature sintering, the back surfaces of the first side plate connection position 201 and the second side plate connection position 202, that is, the inner walls of the first column base right-angle side 203 and the second column base right-angle side 204, can well protect the pressure of the materials, reduce the extrusion on the connection part between the column base 2 and the side plate, and further effectively avoid the occurrence of situations such as cracking and deformation at the joint.

[0048] As Figure 3 、 Figure 5 and Figure 9 shown, the side plate 3 further includes a retaining strip 7 provided on the inner wall of the bottom. Both ends of the retaining strip 7 are limited and clamped by the outer side edges of 2 adjacent column bases 2 on both sides.

[0049] Specifically, in this embodiment, a retaining strip 7 is further provided on the inner wall of the bottom of the side plate 3. The retaining strip 7 is integrally formed with the side plate 3. The length of the retaining strip 7 is less than the minimum distance between 2 adjacent column bases 2, and the height of the retaining strip 7 is greater than the height of the central boss 101.

[0050] In this solution, by setting the retaining strip 7, on the one hand, it can occupy the remaining side plate receiving position 104 at the bottom of the side plate 3, so that the inner wall of the retaining strip 7 can abut against the side wall of the central boss 101. The left end of the retaining strip 7 abuts against the outer side edge of the first side plate connection position 201 on the left column base 2, and the right end of the retaining strip abuts against the outer side edge of the second side plate connection position 202 on the right column base 2.

[0051] Combined with the above-mentioned connection method between the side plate 3 and the column base 2, this embodiment further describes the connection between the side plate 3 with a retaining strip, the column base 2 and the bottom plate 1: One side plate 3 is limited and clamped and connected at both ends by 2 column bases 2 located on its left and right sides, where: The second side plate connecting part 302 is limited and clamped by the second side limiting clamping groove 206 on the left column base 2, and the first side plate connecting part 301 is limited and clamped by the first side limiting clamping groove 205 on the right column base 2; The left end of the baffle 7 is also limited and clamped by the outer side of the first side plate connection position 201 on the left column base 2, and the right end of the baffle 7 is limited and clamped by the outer side of the second side plate connection position 202 on the right column base 2; The inner wall part of the baffle 7 is in perpendicular contact with the outer wall of the central boss 101; The bottom of the baffle 7 and the side plate 3 are perpendicularly connected to the side plate receiving position 104 between the left and right two column bases; The inner walls of the first column base right-angle side 203 and the second column base right-angle side 204 that are perpendicular to each other of the column base 2 are respectively in perpendicular contact with the outer wall of the central boss 101; After the connection positions of the above-mentioned components are in contact, they are further connected by carbon fiber screws 5. The connection method is as described in the connection method realized by the carbon fiber screws mentioned above and will not be elaborated here.

[0052] As an optimization of this embodiment, the thickness of the side plate 3 is equal to the depth of the first column base right-angle side 203 and the second column base right-angle side 204, and the thickness of the baffle 7 is equal to the thickness of the outer sides of the first side plate connection position 201 and the second side plate connection position 202; the thickness of the side plate 3 is equal to the thickness of the baffle 7. By this limitation, the overall connection strength of this graphite crucible is further increased.

[0053] As Figure 4 、 Figure 5 and Figure 7 shown, this solution further includes a partition assembly 8, which is arranged in the cavity and divides the cavity 4 into several independent chambers 401; the height of the partition assembly 8 is not higher than the depth of the cavity 4.

[0054] In this embodiment, by arranging the partition assembly 8 in the cavity 4 to divide the cavity 4 into several independent chambers 401, through physical separation and thermal field optimization, the bottlenecks of uniformity, efficiency and life in the sintering of battery materials by traditional graphite crucibles are solved, especially adapting to the mass production requirements of high-value-added materials such as single-crystal high-nickel and solid electrolytes, including: Avoid material mixing: Prevent the positive electrode materials (such as lithium iron phosphate and ternary materials) with different formulations or batches from contacting each other due to air flow or vibration during the sintering process, resulting in cross-contamination.

[0055] Suppress side reactions: Isolate the volatiles (such as lithium salt decomposition gas) released by different materials to avoid their reaction with each other to generate impurities.

[0056] Improve temperature uniformity: Reduce the volume of a single chamber, reduce the temperature difference between the edge and the center inside the large cavity (usually can be reduced by 50 - 100 °C), and ensure that the material is heated evenly.

[0057] Reduce thermal stress: The independent chamber design reduces the risk of lattice distortion caused by local overheating of the material, improving the sintering yield (typically increased by 5-10%).

[0058] As Figure 8 shown, as a specific embodiment of this solution, the partition assembly 8 includes a first plug board 801 and a second plug board 802 that can be inserted into each other, and slots 701 are provided at the axial positions of the 4 retaining bars 7; A first plug board slot 803 with an upward opening is provided at the axial position of the first plug board 801, and a second plug board slot 804 with a downward opening is provided at the axial position of the second plug board 802. The first plug board slot 803 and the second plug board slot 804 are perpendicularly inserted into each other to form a cross shape; both ends of the first plug board 801 are respectively inserted into the slots 701 on the 2 corresponding retaining bars 7; both ends of the second plug board 802 are respectively inserted into the slots 701 on the 2 corresponding retaining bars 7.

[0059] As an optimization of this embodiment, screw holes 6 are provided at the positions of the side plates corresponding to the sides of the first plug board 801 and the second plug board 802. After the sides of the first plug board 801 and the second plug board 802 abut against the inner walls of the side plates, the carbon fiber screws 5 are pushed in from the outside of the screw holes 6. After passing through the screw holes 6, they are connected to the sides of the first plug board 801 and the second plug board 802, realizing the tight fixation of the partition assembly 8 in the cavity 4 as a support skeleton. In addition, the screw diameter can also be slightly smaller than the screw hole diameter, leaving a certain gap to ensure soft connection between the plug board and the side plate, retaining a little movement gap to improve the impact resistance and seismic resistance of the plug board.

[0060] Under this structure, the cavity 4 is divided into 4 independent chambers 401 to meet the above sintering requirements.

[0061] This embodiment enhances the structural stability of this spliced graphite crucible through this partition assembly, specifically: Anti-deformation ability: The partition assembly 8 serves as an internal support skeleton, which can reduce the deformation probability of the graphite crucible at high temperatures of 800-1200 °C and reduce warping by 20-30%.

[0062] Prevent material collapse: After partitioning, the single-chamber loading capacity is reduced, avoiding the collapse problem caused by excessive powder accumulation.

[0063] As Figure 6 and Figure 8 shown, an outwardly protruding right-angle corner 207 is further provided on the outer side of the bottom of the column foot 2. Correspondingly, a corner receiving position 105 corresponding to the position of the right-angle corner 207 is provided on the outer edge of the column foot receiving position 103.

[0064] In this embodiment, a right-angled corner wrap 207 is provided around the bottom of the column base 2. On the one hand, it can increase the bottom area of the column base 2, thereby increasing the connection area between it and the bottom plate 1, forming a more stable connection. In this structure, when multiple graphite crucibles are longitudinally stacked, the graphite crucible at the bottom, especially the lowermost one, will not be damaged due to the superposition of the pressure above, such as the disintegration of the side plate caused by heavy pressure.

[0065] On the other hand, it can also limit the adjacent stacked graphite crucibles, ensuring a certain interval between adjacent graphite crucibles, such as horizontally between each stacked layer. This is beneficial for the clamping of the manipulator during placement and also beneficial for the stability of the temperature around the graphite crucible during operation, thereby realizing the uniform heating of the materials in the graphite crucible.

[0066] As an optimization of this embodiment, the right-angled corner wrap 207 and the column base 2 are integrally formed, and the wrap receiving position 105 and the bottom plate 1 are integrally formed, which is not only easy to process but also can avoid falling off due to thermal stress or mechanical impact.

[0067] Such as Figure 1 and Figure 2 shown, a stacking limit boss 106 corresponding to the position of the central boss 101 is further provided at the bottom of the bottom plate 1. A closed-loop stacking position 107 is formed between the periphery of the stacking limit boss 106 and the bottom edge of the bottom plate 1 for splicing with the top of the graphite crucible located below.

[0068] Such as Figure 10 and Figure 11 shown. Specifically, in order to achieve the rapid and stable stacking of each graphite crucible during the longitudinal stacking of the graphite crucibles, this embodiment realizes the rapid and accurate positioning with the graphite crucible located below by setting the stacking position, and the stacking limit boss 106 corresponds to the cavity 4 of the graphite crucible located below.

[0069] Under the limitation of the above structure, not only can the rapid stacking of the graphite crucible be realized, but also due to the function of the stacking limit boss 106, it can ensure that the connected graphite crucibles are not easily displaced. For example, when a graphite crucible in the upper layer is displaced to the left due to an external collision, the stacking limit boss 106 at its bottom acts on the right-angled inner wall of the column base 2 of the graphite crucible below, thereby preventing the continuation of the displacement and ensuring the safe operation.

[0070] Such as Figures 9 to 11As shown, a side plate groove 303 is further provided between the first side plate connecting portion 301 and the second side plate connecting portion 302 of the side plate 3. In this embodiment, the side plate groove 303 can be set as a trapezoid. When two graphite crucibles are stacked longitudinally, four exhaust ports are formed between the side plate grooves 303 of the four side plates of the graphite crucible located below and the bottom plate 1 of the graphite crucible located above, which are used to discharge the excess moisture carried or generated during the material sintering process, ensure the normal sintering reaction of the material, and further improve the sintering effect of the battery cathode / anode material.

[0071] The above description is only for explaining the embodiments of the present invention and is not intended to limit the present invention. For those skilled in the art, any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A spliced graphite crucible for sintering positive and negative electrode materials of a battery, characterized in that, Comprising: A bottom plate (1) is provided with a central boss (101) thereon, and a closed-loop receiving position (102) is formed between the periphery of the central boss (101) and the edge of the bottom plate (1); the receiving position (102) includes a column foot receiving position (103) at the corner and a side plate receiving position (104) between adjacent column foot receiving positions (103); Column feet (2), the column feet (2) are perpendicularly connected to the column foot receiving positions (103), a first side plate connection position (201) is provided on one side of the column feet (2), and a second side plate connection position (202) is provided on the other side; Side plates (3), the side plates (3) include symmetrically arranged first side plate connection parts (301) and second side plate connection parts (302), the first side plate connection parts (301) are connected to the first side plate connection positions (201) of the adjacent column feet (2), and the second side plate connection parts (302) are connected to the second side plate connection positions (202) of the adjacent column feet (2); the bottom of the side plates (3) is perpendicularly connected to the side plate receiving positions (104); After the bottom plate (1) is interconnected with each column foot (2) and each side plate (3), a box body with a cavity (4) is formed.

2. The spliced graphite crucible for sintering the positive and negative electrode materials of the battery according to claim 1, wherein The bottom plate (1) is connected to the column feet (2), the bottom plate (1) is connected to the side plates (3), and the side plates (3) are connected to the column feet (2) by carbon fiber screws (5).

3. The spliced graphite crucible for sintering the positive and negative electrode materials of the battery according to claim 1, wherein, The column feet (2) include a first column foot right-angle side (203) and a second column foot right-angle side (204) that are perpendicular to each other, and first side plate limiting clamping grooves (205) and second side plate limiting clamping grooves (206) for limiting and clamping the side plates (3) are respectively formed on the first column foot right-angle side (203) and the second column foot right-angle side (204); the fitting surface of the first side limiting clamping groove (205) and the inner wall of the side plate (3) serves as the first side plate connection position (201), and the fitting surface of the second side limiting clamping groove (206) and the inner wall of the side plate (3) serves as the second side plate connection position (202).

4. The spliced graphite crucible for sintering the positive and negative electrode materials of the battery according to claim 3, characterized in that, The side plates (3) further include a retaining strip (7) provided on the inner wall of the bottom, and both ends of the retaining strip (7) are limited and clamped by the outer sides of 2 adjacent column feet (2).

5. The spliced graphite crucible for sintering the positive and negative electrode materials of the battery according to claim 4, characterized in that, The thickness of the side plates (3) is equal to the depth of the first column foot right-angle side (203) and the second column foot right-angle side (204), the thickness of the retaining strip (7) is equal to the thickness of the outer sides of the first side plate connection position (201) and the second side plate connection position (202); the thickness of the side plates (3) is equal to the thickness of the retaining strip (7).

6. The spliced graphite crucible for sintering the positive and negative electrode materials of the battery according to claim 4, characterized in that, It further includes a partition assembly (8), which is arranged in the cavity and divides the cavity (4) into several independent chambers (401).

7. The spliced graphite crucible for sintering the positive and negative electrode materials of the battery according to claim 6, characterized in that, The partition assembly (8) includes a first plug board (801) and a second plug board (802) that can be inserted into each other, and plug slots (701) are formed at the axial center positions of 4 retaining strips (7); An upward-opening first plug board slot (803) is provided at the axial center position of the first plug board (801), and a downward-opening second plug board slot (804) is provided at the axial center position of the second plug board (802). The first plug board slot (803) and the second plug board slot (804) are perpendicularly inserted into each other to form a cross shape; both ends of the first plug board (801) are respectively inserted into the slots (701) on the two corresponding bars (7); both ends of the second plug board (802) are respectively inserted into the slots (701) on the two corresponding bars (7).

8. The spliced graphite crucible for sintering the positive and negative electrode materials of the battery according to claim 3, characterized in that, A right-angled corner wrap (207) protruding outward is further provided on the outer side of the bottom of the column base (2). Correspondingly, a corner wrap receiving position (105) corresponding to the position of the right-angled corner wrap (207) is provided on the outer edge of the column base receiving position (103).

9. The spliced graphite crucible for sintering the positive and negative electrode materials of the battery according to claim 1, wherein, A stacking limit boss (106) corresponding to the position of the central boss (101) is further provided on the bottom of the bottom plate (1). A closed-loop stacking position (107) is formed between the periphery of the stacking limit boss (106) and the bottom edge of the bottom plate (1) for splicing with the top of the graphite crucible located below.

10. The spliced graphite crucible for sintering the positive and negative electrode materials of the battery according to claim 1 or 8, characterized in that, A side plate groove (303) is further provided between the first side plate connecting portion (301) and the second side plate connecting portion (302) of the side plate (3).

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