Furnace cover for graphitization furnace, graphitization furnace and battery preparation device

Abstract

The utility model provides a furnace cover for a graphitization furnace, the graphitization furnace and a battery preparation device, the furnace cover for the graphitization furnace comprises a furnace cover body and a carbon lining plate, the furnace cover body comprises a shell and a refractory lining body, the shell is provided with an inner cavity with a bottom opening, the refractory lining body is filled in the inner cavity of the shell, and the carbon lining plate is arranged on the lower surface of the refractory lining body. The carbon lining plate is arranged on the lower surface of the refractory lining body, the material component of the carbon lining plate is C, and a carbon material is extremely good in thermal shock resistance and can bear severe temperature change without being damaged; and the chemical components are the same as the lithium battery negative electrode active material graphite, so that the graphitized product cannot be polluted. The carbon lining plate can isolate the direct contact between the refractory lining body in the furnace cover body and the cavity of the graphitization furnace body, so that the problems that the refractory lining body of the furnace cover for the graphitization furnace cracks, peels off, falls powder and pollutes a graphite material in the furnace can be solved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of battery production equipment, in particular to a furnace cover for a graphitization furnace, a graphitization furnace and a battery preparation device. BACKGROUND

[0002] In recent years, with the increasingly wide application range of batteries, the batteries are widely applied to energy storage power supply systems such as hydraulic, thermal, wind and solar power stations, and to multiple fields such as electric tools, electric bicycles, electric motorcycles and electric vehicles. At present, among the negative electrode materials of the batteries, the carbon materials are widely used, and the graphitized carbon materials (also simply referred to as graphite materials) have been widely commercially applied due to the advantages of long service life, stable structure and low cost.

[0003] The graphitization furnace is a device capable of generating graphite materials. In the production process of the graphitization furnace, the core temperature in the graphitization furnace is 2800 DEG C to 3000 DEG C, and the temperature of the upper cavity is 1500 DEG C to 1800 DEG C, which is far higher than the long-term use temperature of conventional refractory materials. And the product in the graphitization furnace is mainly graphite material, and the furnace cover is made of conventional alumina hollow ball material, corundum material, pure corundum material, mullite material, high alumina material and other refractory materials. In the long-term operation process, cracks and surface peeling of the refractory material are prone to occur, which pollutes the product in the furnace and affects the purity of the lithium battery negative electrode material.

[0004] Therefore, seeking a furnace cover for a graphitization furnace capable of solving the problems of cracking, peeling and powder falling of the furnace cover lining, and the pollution of the peeled material to the lithium battery negative electrode material in the graphitization furnace has become one of the focuses of the technical personnel in the field. Content of the utility model

[0005] The application is carried out in view of the above-mentioned problems, and one of the purposes is to provide a furnace cover for a graphitization furnace, a graphitization furnace and a battery preparation device; the furnace cover can solve the problems of cracking, peeling and powder falling of the refractory lining of the traditional furnace cover of the graphitization furnace, and pollution of the lithium battery negative electrode material in the furnace.

[0006] In order to achieve the above-mentioned purpose, the first aspect of the application provides a furnace cover for a graphitization furnace, which comprises a furnace cover body and a carbon lining plate, the furnace cover body comprises a shell and a refractory lining, the shell has an inner cavity with an open bottom, the refractory lining is filled in the inner cavity of the shell, and the carbon lining plate is arranged on the lower surface of the refractory lining.

[0007] By setting the carbon lining plate on the lower surface of the refractory lining of the furnace cover body, the material composition of the carbon lining plate is C, the thermal shock stability of the carbon material is excellent, and it can withstand drastic temperature changes without being damaged; and its chemical composition is the same as that of the lithium negative electrode active material graphite, and it will not pollute the graphitized product. The carbon lining plate can isolate the direct contact between the refractory lining in the furnace cover body and the cavity of the graphitization furnace body, thereby solving the problem of cracking, peeling and powdering of the refractory lining in the furnace cover body of the traditional furnace cover, which pollutes the graphite material in the furnace.

[0008] In some embodiments, the carbon lining plate includes a stack of one or more of a carbon-carbon composite lining plate, a blast furnace carbon brick lining plate, and an electric furnace carbon brick lining plate. In this way, the carbon lining plate described above has high compressive strength and high temperature resistance, and can better protect the refractory lining in the furnace cover body from cracking, peeling and powdering.

[0009] In some embodiments, the thickness of the carbon lining plate is 20-50 mm. In this way, it is more beneficial to protect the refractory lining in the furnace cover body from cracking, peeling and powdering.

[0010] In some embodiments, the furnace cover for graphitization furnace further includes a carbon fastener, the carbon lining plate is installed on the lower surface of the refractory lining through the carbon fastener, and the carbon fastener includes one or more of a carbon-carbon composite bolt and a graphite bolt. In this way, the carbon lining plate can be firmly installed; and compared with the installation mode of sticking, the fastener fixation can better alleviate the separation of the carbon lining plate and the refractory lining due to the inconsistent shrinkage and expansion performance of the carbon lining plate and the refractory lining at high temperature. The use of carbon fasteners helps to reduce pollution to the materials in the furnace.

[0011] In some embodiments, the furnace cover for graphitization furnace further includes a heat insulation layer, and the heat insulation layer is arranged between the refractory lining and the carbon lining plate. In this way, the long-term working temperature of the furnace cover body can be further reduced, the refractory lining in the furnace cover body is protected, and the heat loss in the furnace is reduced, thereby reducing energy consumption.

[0012] In some embodiments, the heat insulation layer includes a stack of one or more of carbon felt, graphite felt and ceramic fiber plate. It can play a good heat insulation effect.

[0013] In some embodiments, the thickness of the heat insulation layer is 10-30 mm. In this way, it is more beneficial to improve the heat insulation effect, protect the refractory lining in the furnace cover body, and reduce the heat loss in the furnace.

[0014] In some embodiments, the graphite furnace cover is provided with a middle part of the graphite furnace cover is provided with an inlet channel for the electrode and raw material to pass through, and the graphite furnace cover further comprises a carbon sleeve installed on the side wall of the inlet channel. In this way, the friction between the material and the side wall of the inlet channel during discharging can be reduced, and the risk of introducing contamination can be reduced. The carbon sleeve can further isolate and protect the refractory lining in the furnace cover body.

[0015] In some embodiments, the carbon sleeve comprises a carbon-carbon composite sleeve, the carbon-carbon composite sleeve has a compressive strength greater than or equal to 120 MPa, and the carbon-carbon composite material in the carbon-carbon composite sleeve has a drum index greater than 99% based on a 0.5 mm particle size. In this way, the carbon sleeve has greater strength, better crushing resistance and wear resistance.

[0016] In some embodiments, the carbon sleeve has a wall thickness of 20-50 mm. In this way, the carbon sleeve can better isolate and protect the refractory lining in the furnace cover body.

[0017] In some embodiments, the graphite furnace cover further comprises an inlet seat and an inlet seat carbon pad; the inlet seat is arranged on the upper surface of the furnace cover body and surrounds the periphery of the inlet channel; and the inlet seat carbon pad is arranged on the inner side wall of the inlet seat. In this way, the direct contact between the raw material and the inlet seat can be effectively isolated, and the mixing of magnetic substances into the graphite product due to the friction during discharging can be alleviated.

[0018] In some embodiments, the refractory lining comprises one or more of an alumina hollow sphere refractory lining, a corundum refractory lining, a mullite refractory lining, and a high-alumina refractory lining.

[0019] The second aspect of the present application provides a graphite furnace comprising the graphite furnace cover of the first aspect of the present application. In this way, by using the graphite furnace cover of the present application in the graphite furnace, the problem of cracking, peeling and powdering of the refractory lining of the traditional graphite furnace cover, which contaminates the lithium battery negative active material in the furnace, can be solved. This is conducive to the long-term stable operation of the graphite furnace.

[0020] The third aspect of the present application provides a battery preparation device comprising the graphite furnace of the second aspect of the present application, which is used for preparing the negative active material of the battery.

[0021] The above description is only a summary of the technical solutions of the present application. In order to more clearly understand the technical means of the present application, the specific embodiments of the present application can be implemented according to the content of the specification, and in order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the following specific embodiments of the present application are described. BRIEF DESCRIPTION OF DRAWINGS

[0022] For a better description and illustration of the embodiments or examples provided by the present application, reference can be made to one or more of the accompanying drawings. Additional details or examples used to describe the drawings should not be considered as limiting the scope of the disclosed application, the presently described embodiments or examples, and any of the best modes of these applications presently understood. Moreover, in all the drawings, like reference numerals refer to like parts throughout the various views. In the drawings:

[0023] Figure 1 A cross-sectional view of a furnace cover for a graphitization furnace according to an embodiment of the present application.

[0024] Figure 2 A top view of a furnace cover for a graphitization furnace according to an embodiment of the present application.

[0025] Figure 3 An enlarged view of a portion of a furnace cover for a graphitization furnace according to an embodiment of the present application.

[0026] BRIEF DESCRIPTION OF DRAWINGS

[0027] 10. A furnace cover for a graphitization furnace; 11. A furnace cover body; 12. A carbon lining; 13. An insulation layer; 14. A feed channel; 15. A carbon sleeve; 16. A feed seat; 17. A feed seat carbon pad; 100. An electrode; 111. A housing; 112. A refractory lining; 113. An anchor. DETAILED DESCRIPTION

[0028] The embodiments of the technical solutions of the present application will be described in detail below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, and cannot limit the protection scope of the present application.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application; the terms "comprising" and "having," and any variations thereof, as used herein are intended to cover a non-exclusive inclusion.

[0030] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase that the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another. It is expressly understood that the embodiments described herein are merely examples from a whole class of comparable embodiments which are claimed as falling within the scope of the present application.

[0031] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " in this paper generally represents that the front and rear associated objects are a "or" relationship.

[0032] In the description of the embodiments of the present application, the term "a plurality of" refers to two or more (including two), and similarly, "a plurality of groups" refers to two or more groups (including two groups), and "a plurality of pieces" refers to two or more pieces (including two pieces).

[0033] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0034] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the technical terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0035] "ranges" disclosed herein can be defined, for example, by both a lower and an upper limit. Ranges can go up to the upper limit and down to the lower limit, each end-point is independently includable or excludable, and any recitation of a range is interchangeable with the inclusion of any and all received values and sub-ranges therein. For example, if a range of 60-120 and 80-110 is listed for a particular parameter, it is understood that a range of 60-110 and 80-120 is also contemplated. Additionally, if a minimum range value of 1 and 2 is listed, and if a maximum range value of 3, 4, and 5 is also listed, then the following ranges are all contemplated: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise indicated, a numerical range "a-b" means a range of any combination of the numbers a and b, wherein a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between 0 and 5 have been listed herein, and "0-5" is merely a shorthand for listing all of those numbers. Additionally, when a parameter is stated to be an integer > 2, it is equivalent to listing the parameter as, for example, integers 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For example, when a parameter is stated to be an integer selected from "2-10", it is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0036] In this application, the open-ended technical features or technical solutions described with the words "comprising", "including", "containing", etc. are not excluded from additional members unless otherwise specified. They can be regarded as providing both a closed feature or solution composed of the listed members, and an open feature or solution including additional members in addition to the listed members. For example, A includes a1, a2, and a3. Unless otherwise specified, it can also include other members, or it can not include additional members. It can be regarded as providing a feature or solution that "A is composed of a1, a2, and a3", and also providing a feature or solution that "A includes a1, a2, and a3, and also includes other members". In this application, unless otherwise specified, A (such as B) means that B is a non-limiting example of A. It can be understood that A is not limited to B.

[0037] In this application, "optionally", "optional", or "optional" means that it can or can not exist, i.e. it means that it is selected from two parallel solutions of "yes" or "no". If there are multiple "options" in a technical solution, and unless otherwise specified, there is no contradiction or mutual restriction.

[0038] In the production process of graphitization furnace, the core temperature in the graphitization furnace is usually 2800-3000℃, and the temperature of the upper cavity is generally 1500-1800℃, which is far beyond the long-term use temperature of conventional refractory materials. The conventional furnace cover of graphitization furnace usually adopts alumina hollow ball material, corundum, mullite, high alumina, etc. to make refractory lining; the CO, H2, CH4, H2S, etc. gases volatilized from the carbonaceous raw materials (such as petroleum coke) in the preheating, calcination and graphitization process will invade the interior of the refractory lining and cause erosion; in the long-term operation of the graphitization furnace, cracks and surface peeling of the refractory material are prone to occur under the action of thermal stress and chemical erosion, which affects the service life of the graphitization furnace; and the peeling refractory material falling into the furnace will pollute the products in the furnace and affect the purity of the lithium negative electrode material.

[0039] In addition, the core temperature in the furnace of the graphitization furnace is extremely high, and the traditional refractory material falling from the furnace cover into the furnace will react with the carbonaceous material to generate aluminum carbide and other substances, which have a boiling point of about 2200℃ and will gasify at the core temperature of 2800-3000℃ and diffuse to the upper part and the surrounding area. After diffusing to the preheating area and other surrounding areas with a temperature lower than 2200℃, it is re-liquefied, part of which flows into the core area to form a cycle, and part of which flows into the area with a melting point lower than 2100℃ to re-solidify, bond the material, form crust and clinker, and affect the smoothness of the material downward.

[0040] The continuous graphitization furnace is different from the traditional Acheson graphitization furnace, batch furnace and other periodic operation and dismantled furnace body. The continuous graphitization furnace needs to be operated continuously and stably under high load for a long time, and the furnace cover lining cannot be replaced regularly. Therefore, how to protect the refractory lining material of the furnace cover from cracking, falling off and peeling, or even if part of it peels off, it does not affect the purity of the material in the furnace and the continuous and smooth operation of the kiln, has become a problem to be solved.

[0041] For the above problems, the traditional method is usually to brush a layer of high-temperature resistant fireproof coating on the traditional refractory lining in the furnace cover to fill the pores on the surface of the refractory lining and prevent the CO, H2, CH4, H2S, etc. gases volatilized from the carbonaceous raw materials in the preheating, calcination and graphitization process from invading the interior of the refractory lining and causing erosion.

[0042] However, due to the thermal stress, chemical erosion, mechanical scouring and defects of the coating material itself under high temperature, the coating is also at risk of peeling and failure in the long-term use process. The shrinkage and expansion performance of the coating material itself under high temperature cannot be completely consistent with the cooperation of the refractory furnace lining material at different temperatures, which is easy to cause peeling between the two. The peeling and falling of the coating will still be a great pollution to the negative electrode material and will seriously affect the product quality.

[0043] Based on this, please refer to Figure 1 ,Figure 2 and Figure 3 In one embodiment, the application provides a furnace cover 10 for a graphitization furnace, which includes a furnace cover body 11 and a carbon lining plate 12. The furnace cover body 11 includes a shell 111 having an open-bottomed inner cavity and a refractory lining 112 filled in the inner cavity of the shell 111. The carbon lining plate 12 is arranged on the lower surface of the refractory lining 112.

[0044] The furnace cover 10 for the graphitization furnace described above has the carbon lining plate 12 arranged on the lower surface of the refractory lining 112. The material of the carbon lining plate 12 is C, which has excellent thermal shock stability and can withstand drastic temperature changes without being damaged. Moreover, the chemical composition of the carbon lining plate 12 is the same as that of the lithium negative electrode active material graphite, and thus the carbon lining plate 12 does not pollute the graphitized product. The carbon material has good high-temperature resistance and does not melt at high temperatures, and directly sublimates at about 3500°C.

[0045] The carbon lining plate 12 arranged on the lower surface of the refractory lining 112 can prevent the traditional refractory material such as corundum from directly contacting the cavity of the furnace body of the graphitization furnace, and can prevent the gases such as CO, H2, CH4, and H2S volatilized during the preheating, calcination, and graphitization of the carbon raw material from invading the interior of the refractory lining 112 and eroding the material of the refractory lining 112. Thus, the problem of the cracking, peeling, and powdering of the refractory lining 112 of the traditional furnace cover of the graphitization furnace and the pollution of the lithium negative electrode active material in the furnace can be solved.

[0046] It can be understood that the carbon lining plate 12 is located on the lower surface of the refractory lining 112 and serves as the working surface of the furnace cover 10 for the graphitization furnace in contact with the inner cavity of the graphitization furnace. The lower surface of the refractory lining 112 refers to the side of the refractory lining 112 facing the furnace body.

[0047] Specifically, the material of the refractory lining 112 can be a traditional refractory material, including one or more of alumina hollow sphere refractory material, corundum refractory material, mullite refractory material, and high-alumina refractory material. The shell 111 can be made of steel. In some specific examples, the refractory lining 112 is a stack of one or more of alumina hollow sphere refractory lining, corundum refractory lining, mullite refractory lining, and high-alumina refractory lining.

[0048] In addition, a plurality of anchoring members 113 extending into the interior of the refractory lining 112 can be arranged on the shell 111 to reinforce the refractory lining 112.

[0049] In some embodiments, the material of the carbon lining plate 12 includes one or more of carbon-carbon composite material, blast furnace carbon brick, and electric furnace carbon brick. The carbon lining plate 12 made of the above-mentioned material has high compressive strength and high-temperature resistance, and can well protect the traditional refractory lining in the furnace cover body 11 from cracking, peeling, and powdering.

[0050] In some specific examples, the carbon lining 12 comprises a stack of one or more of carbon-carbon composite lining, blast furnace carbon brick lining, and electric furnace carbon brick lining.

[0051] The carbon-carbon composite material is a high-performance composite material made of carbon fiber as the reinforcing body and carbon matrix as the continuous phase through chemical vapor deposition, impregnation carbonization, and other composite processes. The blast furnace carbon brick and the electric furnace carbon brick are carbon refractory materials made of anthracite and graphite as the main raw materials, with a small amount of binder (such as coal tar pitch) added, and then molded and baked.

[0052] In some embodiments, the carbon lining 12 has a mass content of the main component C greater than 85%, an ash content less than 10%, a compressive strength greater than 25 MPa, a bending strength greater than 5 MPa, and a density greater than 1.5 g / cm 3 .

[0053] In some embodiments, the thickness of the carbon lining 12 is 20-50 mm. Optionally, the thickness of the carbon lining 12 is 30 mm. Controlling the thickness of the carbon lining 12 within the above range is more conducive to protecting the refractory lining 112 inside the furnace cover body 11 from cracking, peeling, and powdering.

[0054] It can be understood that the thickness of the carbon lining 12 can be 20 mm, 22 mm, 25 mm, 28 mm, 30 mm, 32 mm, 35 mm, 38 mm, 40 mm, 42 mm, 45 mm, 48 mm, 50 mm, and any value within the range formed by any two of the above values.

[0055] In some embodiments, the graphite furnace cover 10 further comprises a carbon fastener (not shown in the figure), and the carbon lining 12 is installed on the lower surface of the refractory lining 112 through the carbon fastener. The carbon fastener comprises one or more of carbon-carbon composite bolts and graphite bolts.

[0056] Installing the carbon lining 12 on the lower surface of the refractory lining 112 through the fastener can make the carbon lining 12 firmly installed. Moreover, compared with the installation method of pasting, fixing through the fastener can better alleviate the situation that the carbon lining 12 and the refractory lining 112 separate due to the inconsistent shrinkage and expansion performance of the carbon lining 12 and the refractory lining 112 at high temperatures. Using carbon fasteners such as carbon-carbon composite bolts and graphite bolts, which are made of C material like the materials in the graphite furnace, is more conducive to reducing pollution to the materials in the furnace.

[0057] It should be noted that the carbon lining plate 12 can be a whole piece, or can be processed into a tile-like shape, and is fixed by carbon fasteners, serving as a working surface of the graphite furnace cover 10 in contact with the inner cavity of the graphitization furnace.

[0058] Referring to Figure 1 and Figure 3 In some embodiments, the graphite furnace cover 10 further comprises a heat insulation layer 13 arranged between the refractory lining 112 and the carbon lining plate 12. By arranging the heat insulation layer 13 between the refractory lining 112 and the carbon lining plate 12, the long-term working temperature of the refractory lining 112 can be further reduced, the refractory lining 112 is protected, and the heat loss in the furnace is reduced, thereby reducing energy consumption.

[0059] In the present application, the heat insulation layer 13 can be installed between the refractory lining 112 and the carbon lining plate 12 by pasting. The carbon fasteners can pass through the carbon lining plate 12 and the heat insulation layer 13 to install the carbon lining plate 12 on the furnace cover body 11.

[0060] In some embodiments, the heat insulation layer 13 comprises a stack of one or more of carbon felt, graphite felt, and ceramic fiber board. The thermal conductivity coefficient thereof is generally less than 0.5 w / (m·k), which can play a good heat insulation role, create a relatively mild working condition for the refractory lining 112, and prolong the overall service life of the furnace cover.

[0061] In some embodiments, the thickness of the heat insulation layer 13 is 10mm-30mm. The heat insulation layer 13 with the above thickness is more conducive to improving the heat insulation effect, protecting the refractory lining 112, and reducing the heat loss in the furnace. It can be understood that the thickness of the heat insulation layer 13 can be 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, 26mm, 27mm, 28mm, 29mm, 30mm, and any value within the range formed by any two of the above values.

[0062] Referring to Figure 1 and Figure 2In some embodiments, a feed channel 14 for the electrode 100 and raw materials is provided in the middle of the graphitization furnace cover 10. The graphitization furnace cover 10 also includes a carbon sleeve 15 installed on the inner sidewall of the feed channel 14. Installing the carbon sleeve 15 on the inner sidewall of the feed channel 14 reduces friction between the material and the inner sidewall of the feed channel 14 during feeding, due to the excellent lubricity of carbon. Furthermore, the carbon and graphite, the negative electrode material for lithium batteries, share the same chemical composition of C, which reduces the risk of contamination. Furthermore, the carbon sleeve 15 further insulates and protects the refractory lining 112 of the furnace cover.

[0063] like Figure 1 and Figure 3 As shown, in some specific examples, the shell 111 is located on the upper surface and outer side wall of the furnace cover 10 for the graphitization furnace, forming an "L"-shaped structure; the shell 111, the carbon lining 12 and the carbon sleeve 15 together form a chamber, and the refractory lining 112 is located in the chamber.

[0064] In some embodiments, the carbon sleeve 15 is a carbon-carbon composite sleeve, wherein the material includes a carbon-carbon composite material; the carbon-carbon composite sleeve has a compressive strength greater than or equal to 120 MPa, a carbon content greater than 98%, an ash content less than 200 ppm, and a tumble index greater than 99% based on a 0.5 mm particle size. By using the aforementioned carbon-carbon composite material as the carbon sleeve 15, the carbon sleeve 15 can be made stronger, has better resistance to crushing and wear, and has a lower ash content, thereby minimizing the risk of contamination to the graphite product.

[0065] The tumble index is a key indicator of a sample's resistance to abrasion and crushing, primarily reflecting its ability to maintain morphological integrity under dynamic friction and collision conditions. Carbon-carbon composite particles are placed in a rotating drum and rotated. The resulting powder is removed through the rolling impact of the particles and friction in the drum. The post-test "retention rate" of the particles is then calculated to characterize their abrasion resistance. A higher tumble index indicates greater resistance to crushing and wear. Specifically, tumble index = (mass of particles larger than a certain critical size after the test / total mass of the original sample) × 100%. In some embodiments, the critical size is 0.5 mm.

[0066] In some embodiments, the carbon sleeve 15 has a wall thickness of 20-50 mm. Further optionally, the carbon sleeve 15 has a wall thickness of 30 mm. Controlling the wall thickness of the carbon sleeve 15 within the above range can better insulate and protect the refractory lining 112 of the furnace cover. It is understood that the wall thickness of the carbon sleeve 15 can be 20 mm, 22 mm, 25 mm, 28 mm, 30 mm, 32 mm, 35 mm, 38 mm, 40 mm, 42 mm, 45 mm, 48 mm, 50 mm, or any value within the range formed by any two of the above values.

[0067] Referring to Figure 1 and Figure 2 In some embodiments, the furnace cover 10 for graphitization further comprises a feeding seat 16 and a feeding seat carbon pad 17. The feeding seat 16 is arranged on the upper surface of the furnace cover body 11 and surrounds the periphery of the feeding channel 14. The feeding seat carbon pad 17 is arranged on the inner side wall of the feeding seat 16.

[0068] By arranging the feeding seat 16 on the upper surface of the furnace cover body 11 and surrounding the periphery of the feeding channel 14, it is convenient to feed the raw materials into the furnace body of the graphitization furnace through the feeding channel 14. The feeding seat 16 can be made of steel plate and has sufficient strength. By arranging the feeding seat carbon pad 17 on the inner side wall of the feeding seat 16, the direct contact between the raw materials and the steel feeding seat 16 can be effectively insulated, and the mixing of magnetic substances into the graphite product due to the friction of the raw materials can be alleviated.

[0069] Specifically, referring to Figure 1 The vertical section of the feeding seat 16 is in an inverted trapezoidal structure, and the feeding seat 16 as a whole is in an inverted circular table shape with the upper and lower surfaces being open. The diameter of the upper end opening of the feeding seat 16 is greater than that of the lower end opening. The feeding seat carbon pad 17 is also in an inverted circular table shape with the upper and lower surfaces being open, and the shape of the feeding seat carbon pad 17 is adapted to that of the feeding seat 16. In this way, it is more convenient to feed the materials.

[0070] In some embodiments, the thickness of the feeding seat carbon pad 17 is 20-50 mm. Further optionally, the thickness of the feeding seat carbon pad 17 is 30 mm. The feeding seat carbon pad 17 with the above thickness can effectively insulate the direct contact between the raw materials and the steel feeding seat 16.

[0071] It is understood that the thickness of the feeding seat carbon pad 17 can be 20 mm, 22 mm, 25 mm, 28 mm, 30 mm, 32 mm, 35 mm, 38 mm, 40 mm, 42 mm, 45 mm, 48 mm, 50 mm, or any value within the range formed by any two of the above values.

[0072] In some embodiments, the material of the carbonaceous pad 17 of the feed seat can be one or more of carbon-carbon composite material, blast furnace carbon brick and electric furnace carbon brick. The carbonaceous pad 17 of the feed seat with the above-mentioned material has high compressive strength and high-temperature resistance, and can better isolate the raw materials from direct contact with the steel feed seat 16.

[0073] The present application forms a composite furnace cover structure containing a feed channel 14 by adopting the carbonaceous lining plate 12, the heat insulation layer 13, the carbonaceous sleeve 15 and the carbonaceous pad 17 of the feed seat, and combining with the carbonaceous fastener, the shell 111, the refractory lining 112, the anchor 113 and other components, which can greatly reduce the pollution of the graphite product caused by the furnace cover during the feeding and operation of the graphitization furnace, and enable the furnace cover and the graphitization furnace to operate stably for a long time.

[0074] The manufacturing method of the furnace cover 10 for the graphitization furnace according to an embodiment of the present application is as follows:

[0075] First, the shell 111 of the furnace cover is inverted, and the 310S high-temperature stainless steel anchor is welded on the shell 111; the total height of the anchor is 200 mm, and the ratio of the height of the anchor to the thickness of the cast refractory lining 112 is 4:5; then the mold is supported, and the corundum castable is vibrated and cast, and the thickness of the cast lining is 250 mm; after the castable is solidified, the drying and baking processes are performed, the drying system is 110℃×72h, and then the temperature is raised to 600℃ at a temperature rising speed of 5℃ / h~8℃ / h for baking, so that the free water, the chemically combined water and the crystal water in the refractory lining 112 are completely removed.

[0076] Secondly, the pasting and installation of the heat insulation layer 13 are performed, the thickness of the heat insulation layer 13 is controlled to be 10mm~30mm, and the material of the heat insulation layer 13 can be one or more of carbon felt, graphite felt, ceramic fiber board and other thermal insulation materials.

[0077] Then, the installation of the carbonaceous lining plate 12 is performed, the installation thickness of the carbonaceous lining plate 12 is controlled to be 20mm~50mm, and the material of the carbonaceous lining plate 12 can be carbon-carbon composite material, blast furnace carbon brick, electric furnace carbon brick and the like, which mainly contains C greater than 85%, ash less than 10%, compressive strength greater than 25MPa, bending strength greater than 5MPa, and density greater than 1.5g / cm 3 The carbonaceous lining plate 12 is fixedly installed on the lower surface of the furnace cover body 11 by using carbon-carbon composite material bolts or graphite bolts.

[0078] Then, the carbon sleeve 15 and the carbon pad 17 are installed. The carbon sleeve 15 is sleeved in the feeding channel 14, and then the feeding seat 16 and the carbon pad 17 are installed. The carbon sleeve 15 can be made of carbon-carbon composite material, which contains more than 98% of carbon, less than 200 ppm of ash, and a compressive strength of more than 120 MPa. The thickness of the carbon pad 17 is controlled to be 20-50 mm, and the material can be one or more of carbon-carbon composite material, blast furnace carbon brick, and electric furnace carbon brick.

[0079] In this way, the carbon lining plate 12, the feeding seat 16, the shell 111, the refractory lining 112, the anchor 113, the heat insulation layer 13, the carbon pad 17, and the carbon sleeve 15 form a composite furnace cover containing the feeding channel 14, ensuring that the continuous graphitization furnace is not contaminated during discharging, and the furnace cover is stable during long-term operation. When the graphitization furnace is running, the carbon raw material passes through the feeding seat 16 and the feeding channel 14 into the furnace body of the graphitization furnace, and is preheated and graphitized by the graphite electrode, thereby obtaining the negative active material graphite for batteries.

[0080] An embodiment of the present application provides a graphitization furnace (not shown in the figure), which comprises the furnace cover 10 for the graphitization furnace described above. By using the furnace cover 10 for the graphitization furnace described above in the graphitization furnace, the problem of cracking, peeling, and powdering of the refractory lining of the traditional furnace cover of the graphitization furnace, which contaminates the lithium battery negative active material in the furnace, can be solved, and the graphitization furnace can be operated stably for a long time.

[0081] It can be understood that the graphitization furnace comprises a furnace body and a furnace cover. The furnace body has a furnace cavity, and carbon raw materials are graphitized in the furnace cavity to obtain graphite products. The upper end of the furnace body is open, and the furnace cover covers the upper end of the furnace body. Further, the graphitization furnace further comprises positive and negative electrodes for heating the materials in the furnace cavity to graphitize the materials. The graphitization furnace can further comprise a temperature control system, an atmosphere control system, a cooling system, a power supply system, and a material conveying system.

[0082] In some examples, the graphitization furnace of the present application is a continuous graphitization furnace. The production process of the continuous graphitization furnace adopts a direct current heating method. Under the action of an external voltage, the continuous graphitization furnace generates Joule heat in the raw materials (such as petroleum coke) in the furnace through positive and negative electrodes, continuously heats and heats up to make the core temperature reach 2800-3000℃ to complete the graphitization of the raw materials.

[0083] An embodiment of the present application provides a battery preparation device (not shown in the figure), which comprises the graphitization furnace described above, and the graphitization furnace is used to prepare the negative active material graphite for batteries.

[0084] It can be understood that the battery preparation device can include related equipment for producing other materials of the battery in addition to the graphitization furnace for producing the negative active material graphite of the battery. The battery preparation device can be a battery production line, and the plurality of equipment in the battery production line can be arranged in the same centralized place or can be arranged in separate different places.

[0085] The above description of the various embodiments tends to emphasize differences between the various embodiments, and the same or similar parts can be referred to each other, and will not be described herein for the sake of brevity.

[0086] It should be noted that the present application is not limited to the above-described embodiments. The above-described embodiments are merely examples, and embodiments having substantially the same configuration and playing the same role and effect as the technical idea within the scope of the technical solution of the present application are included in the technical scope of the present application. Furthermore, within the scope of the gist of the present application, various modifications that can be thought of by those skilled in the art, other modes constructed by combining part of the elements of the embodiments are also included in the scope of the present application.

Claims

1. A furnace cover for a graphitizing furnace, characterized in that: The furnace cover body comprises a furnace cover body and a carbon lining. The furnace cover body comprises a shell and a refractory lining. The shell has an inner cavity with an open bottom. The refractory lining is filled in the inner cavity of the shell. The carbon lining is arranged on the lower surface of the refractory lining.

2. The graphitization furnace cover according to claim 1, characterized in that: The carbonaceous lining plate comprises a stack of one or more of a carbon-carbon composite material lining plate, a blast furnace carbon brick lining plate and an electric furnace carbon brick lining plate.

3. The graphitization furnace cover according to claim 1, characterized in that: The thickness of the carbon lining plate is 20 mm to 50 mm.

4. The graphitization furnace cover according to claim 1, characterized in that: The graphitization furnace cover further includes a carbon fastener, through which the carbon lining plate is mounted on the lower surface of the refractory lining. The carbon fastener includes one or more of a carbon-carbon composite bolt and a graphite bolt.

5. The graphitization furnace cover according to any one of claims 1 to 4, characterized in that: The graphitization furnace cover further includes a heat insulation layer, which is provided between the refractory lining and the carbonaceous lining plate.

6. The graphitization furnace cover according to claim 5, characterized in that: The thermal insulation layer includes a laminate of one or more of carbon felt, graphite felt and ceramic fiberboard.

7. The graphitization furnace cover according to claim 5, characterized in that: The thickness of the heat insulation layer is 10 mm to 30 mm.

8. The graphitization furnace cover according to any one of claims 1 to 4 and 6 to 7, characterized in that: A feeding channel for electrodes and raw materials is provided in the middle of the graphitization furnace cover. The graphitization furnace cover also includes a carbon sleeve, and the carbon sleeve is installed on the side wall of the feeding channel.

9. The graphitization furnace cover according to claim 8, characterized in that: The carbonaceous casing comprises a carbon-carbon composite casing, the compressive strength of the carbon-carbon composite casing is greater than or equal to 120 MPa, and the tumble index of the carbon-carbon composite material in the carbon-carbon composite casing is greater than 99% based on a particle size of 0.5 mm.

10. The graphitization furnace cover according to claim 8, characterized in that: The carbon sleeve has a wall thickness of 20 mm to 50 mm.

11. The graphitization furnace cover according to claim 8, characterized in that: The graphitization furnace cover also includes a feed seat and a carbonaceous pad for the feed seat; the feed seat is arranged on the upper surface of the furnace cover body and is arranged around the periphery of the feed channel; the carbonaceous pad for the feed seat is arranged on the inner side wall of the feed seat.

12. The graphitization furnace cover according to any one of claims 1 to 4, 6 to 7, and 9 to 11, characterized in that: The refractory lining includes a laminate of one or more of an alumina hollow ball refractory lining, a corundum refractory lining, a mullite refractory lining and a high-alumina refractory lining.

13. A graphitization furnace, characterized in that: The invention comprises the graphitization furnace cover according to any one of claims 1 to 12.

14. A battery preparation device, characterized in that: The graphitization furnace according to claim 13 is used to prepare negative electrode active materials for batteries.

Images