Method for manufacturing electrically conductive column for box-type graphitization furnace and application thereof

Abstract

The application belongs to the field of graphite products, and discloses a manufacturing method of an electrically conductive column for a box-type graphitization furnace and application of the electrically conductive column. The manufacturing method comprises the following steps: mixing graphite negative electrode material and a binder to obtain a paste, and then sequentially performing die forming, drying, baking and turning processing on the paste to obtain the electrically conductive column. The electrically conductive column is used in the box-type graphitization furnace, and is used as negative electrode material after graphitization high-temperature treatment and pulverization. The manufacturing method is simple and environmentally friendly, improves the product qualification rate, and improves the production capacity of the graphitization furnace by using the electrically conductive column. The application is suitable for mass production of the electrically conductive column for the box-type graphitization furnace.

Description

Technical Field

[0001] This invention belongs to the field of graphite products and relates to a method for manufacturing a conductive column, specifically a method for manufacturing a conductive column for a box-type graphitization furnace and its application. Background Technology

[0002] Graphite anode materials are widely used in the new energy vehicle industry, aerospace industry, energy storage industry, lithium batteries, supercapacitors, solar cells, fuel cells, and other fields. In recent years, the market size of graphite anode materials has continued to expand. Currently, graphite anode materials are mainly artificial graphite anode materials, prepared by graphitizing petroleum coke, needle coke, etc. The graphitization process is a key factor affecting the quality of graphite anode materials. Currently, the types of heating furnaces that can perform graphitization processes include Atchison graphitization furnaces, internal series graphitization furnaces, and box-type graphitization furnaces. Among them, box-type graphitization furnaces have become the preferred choice for researchers due to their advantages such as high capacity and low energy consumption.

[0003] Box-type graphitization furnaces mainly consist of graphitized box plates and conductive columns. The conductive columns are manufactured using graphitized coke as raw material and pitch as a binder, through processes such as molding, calcination, graphitization, and processing. On the one hand, this manufacturing process is complex and requires a large amount of pitch, which is moderately toxic, harmful to worker health, and environmentally unfriendly. On the other hand, if the stress generated during the molding process cannot be effectively released, delamination is highly likely to occur. Furthermore, the temperature differences generated during calcination can easily lead to cracks during the carbonization and decomposition of the binder. Therefore, the scrap rate of conductive columns during molding and calcination is high, increasing costs. In addition, the conductive columns occupy approximately 20% of the material box volume, and their added value is low after use, resulting in reduced furnace space and, to some extent, lowering the furnace's production capacity. Summary of the Invention

[0004] To address the above-mentioned shortcomings in the existing technology, the present invention aims to provide a method for manufacturing conductive columns for box-type graphitization furnaces, so as to achieve a simple and environmentally friendly process and improve the product qualification rate.

[0005] The present invention also provides an application of a conductive column prepared by a method for manufacturing conductive columns for box-type graphitization furnaces, in order to improve the production capacity of graphitization furnaces.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for manufacturing a conductive column for a box-type graphitization furnace includes the following steps:

[0008] The graphite anode material and binder are mixed to obtain a paste;

[0009] The paste is sequentially molded, dried, calcined, and machined to obtain conductive pillars;

[0010] The particle size of the graphite anode material is ≤0.045mm;

[0011] The adhesive is a liquid adhesive and / or a dispersible adhesive;

[0012] Liquid binders include phenolic resins;

[0013] The dispersible binder is prepared by dispersing a solid binder in a solvent, wherein the solid binder includes carboxymethyl cellulose, xanthan gum, starch and polyvinyl alcohol;

[0014] The solvent includes water and ethanol solution, wherein the mass fraction of ethanol in the ethanol solution is 25-75%;

[0015] The compression molding process involves segmented compression; the calcination process involves segmented heating.

[0016] The graphite anode material is a synthetic graphite anode material.

[0017] The solvent is used to disperse the solid binder. Any solvent that disperses the solid binder is acceptable, including water, methanol solution, ethanol solution, isopropanol solution, etc.

[0018] As a limitation of the present invention, the mass ratio of the graphite anode material to the binder is 65-80:35-20. As a limitation of the present invention, the amount ratio of the graphite anode material, binder, and solvent is 65-80g:35-20g:70-90mL.

[0019] As a further limitation of the present invention, the vacuum degree of the compression molding is ≤-0.08MPa.

[0020] As a further limitation of the present invention, the segmented pressurization includes the following steps performed sequentially:

[0021] The first stage of pressurization involves increasing the pressure to 8-10 MPa at a rate of 0.1-2 MPa / s.

[0022] The second stage of pressurization involves increasing the pressure to 11-15 MPa at a rate of 0.1-3 MPa / s.

[0023] The third stage involves pressurizing at a rate of 0.1–5 MPa / s to 16–22 MPa and maintaining the pressure for 1–3 minutes.

[0024] As a limitation of the present invention, the drying temperature is 80-110°C and the drying time is 36-72 hours.

[0025] As a further limitation of the present invention, the calcination temperature is 600-800°C.

[0026] As a further limitation of the present invention, the segmented heating includes the following steps performed sequentially:

[0027] The first stage of heating involves raising the temperature to 300℃ at a rate of 0.1–1.25℃ / h.

[0028] The second stage involves heating at a rate of 0.1–0.8 °C / h to 301–599 °C.

[0029] The third stage involves heating at a rate of 0.1–1.0 °C / h to 600–800 °C.

[0030] The present invention also provides an application of the conductive column prepared by the above technical solution, wherein the conductive column is used in a box-type graphitization furnace, and after a first high-temperature graphitization treatment, it is ground and used as a negative electrode material.

[0031] By adopting the above-described technical solution, the beneficial effects achieved by this invention compared to the prior art are as follows:

[0032] (1) The present invention uses graphite negative electrode material as raw material, mixes it with binder, and obtains conductive column by molding, drying, calcining and simple turning. The preparation process is simple and environmentally friendly. It does not involve asphalt in the preparation process and is friendly to workers and the environment. The use of segmented pressure molding and segmented heating calcination significantly improves the product qualification rate.

[0033] (2) In this invention, the paste is subjected to segmented pressurization technology during the molding process. Segmented pressurization can make the paste "breathe" during the molding process and release the stress during the pressurization process segment by segment, effectively releasing the elastic aftereffect of the paste, reducing the occurrence of delamination during the molding process, and ultimately improving the molding qualification rate.

[0034] (3) In this invention, the calcination adopts a segmented heating calcination technology. The first stage of heating is mainly to promote the evaporation of moisture. The second stage of heating is to decompose and carbonize the binder. The third stage of heating is used for further carbonization. Since calcination cracks are very likely to occur during the decomposition and carbonization of the binder, the heating rate in this process is controlled at 0.1 to 0.8℃ / h to keep the temperature difference generated by the heating in various places within a reasonable range, effectively reducing the occurrence of cracks and achieving an effective improvement in the calcination yield.

[0035] (4) The conductive column prepared in this invention can not only be used as a conductive column in a box-type graphitization furnace, but also be graphitized while working in the box-type graphitization furnace. At the same time, the box-type graphitization furnace can also be used to graphitize other materials. After the conductive column undergoes a high-temperature graphitization treatment, it can be easily ground to obtain a product for battery preparation, which effectively improves the production capacity of the box-type graphitization furnace.

[0036] In summary, the manufacturing method and application of the conductive column for box-type graphitization furnace of the present invention are not only simple and environmentally friendly, improving the product qualification rate, but also increasing the production capacity of graphitization furnace, and are suitable for mass production of conductive columns for box-type graphitization furnaces. Detailed Implementation

[0037] The present invention will be further described in detail below through specific embodiments. It should be understood that the described embodiments are only used to explain the present invention and do not limit the present invention.

[0038] Unless otherwise specified, all materials and reagents used in the embodiments of this invention are commercially available. Experimental methods not specifically described in the embodiments are generally performed under standard conditions or as recommended by the manufacturer.

[0039] Example 1: A method for manufacturing a conductive column for a box-type graphitization furnace

[0040] This embodiment describes a method for manufacturing a conductive column for a box-type graphitization furnace, specifically including the following steps:

[0041] (1) Paste preparation: Take 8 kg of graphite anode material and 2 kg of phenolic resin and mix them evenly to obtain paste.

[0042] (2) Compression molding: After placing the paste into the mold, adjust the vacuum degree to -0.08 MPa, perform the first stage of pressurization at a rate of 1 MPa / s to pressurize to 9 MPa, perform the second stage of pressurization at a rate of 1.5 MPa / s to pressurize to 13 MPa, and perform the third stage of pressurization at a rate of 3.5 MPa / s to pressurize to 19 MPa. Maintain the pressure for 2 minutes, then adjust to normal atmospheric pressure, remove the product, and obtain the raw product with a yield of 96%.

[0043] (3) Drying: Place the raw product in an oven, set the temperature to 95℃, dry for 54 hours, and then take it out.

[0044] (4) Calcination: The dried raw product is placed in the car bottom furnace and heated in the first stage at a rate of 0.63℃ / h to 300℃. Then, it is heated in the second stage at a rate of 0.4℃ / h to 400℃. Finally, it is heated in the third stage at a rate of 0.5℃ / h to 700℃. The product is then allowed to cool naturally to room temperature and removed to obtain the conductive column material. The yield is 89%.

[0045] (5) Turning: The conductive post material is processed by simple turning to obtain the conductive post.

[0046] Example 2: A method for manufacturing a conductive column for a box-type graphitization furnace

[0047] The only difference between this embodiment and Embodiment 1 is that:

[0048] (1) Paste preparation: Take 8L of 75%wt ethanol solution, add 2kg of carboxymethyl cellulose and mix evenly, then mix evenly with 8kg of graphite anode material to obtain paste.

[0049] In this embodiment, the yield of the raw product is 97%, and the yield of the conductive column material is 88%.

[0050] Example 3: A method for manufacturing a conductive column for a box-type graphitization furnace

[0051] The only difference between this embodiment and Embodiment 1 is that:

[0052] (1) Paste preparation: Take 7L of 75%wt ethanol solution, add 2kg of xanthan gum and mix evenly, then mix evenly with 8kg of graphite anode material to obtain paste.

[0053] In this embodiment, the yield of the raw material is 96%, and the yield of the conductive column material is 86%.

[0054] Example 4: A method for manufacturing a conductive column for a box-type graphitization furnace

[0055] The only difference between this embodiment and Embodiment 1 is that:

[0056] (1) Paste preparation: Take 9L of 75%wt ethanol solution, add 2kg of starch and mix evenly, then mix evenly with 8kg of graphite anode material to obtain paste.

[0057] In this embodiment, the yield of the raw material is 98%, and the yield of the conductive column material is 89%.

[0058] Example 5: A method for manufacturing a conductive column for a box-type graphitization furnace

[0059] The only difference between this embodiment and Embodiment 1 is that:

[0060] (1) Paste preparation: Take 9L of water, add 2kg of polyvinyl alcohol and mix evenly, then mix evenly with 8kg of graphite anode material to obtain paste.

[0061] In this embodiment, the yield rate of the raw product is 98%, and the yield rate of the conductive column material is 88%.

[0062] Example 6: A method for manufacturing a conductive column for a box-type graphitization furnace

[0063] In this embodiment, the binder includes phenolic resin and carboxymethyl cellulose, with a mass ratio of phenolic resin to carboxymethyl cellulose of 1:1.

[0064] The only difference between this embodiment and Embodiment 1 is that:

[0065] (1) Paste preparation: Take 6.75L of 75%wt ethanol solution, add 1kg of carboxymethyl cellulose and mix evenly, add 1kg of phenolic resin and mix evenly, then mix evenly with 8kg of graphite anode material to obtain paste.

[0066] In this embodiment, the yield of the raw material is 97%, and the yield of the conductive column material is 89%.

[0067] Example 7: A method for manufacturing a conductive column for a box-type graphitization furnace

[0068] In this embodiment, the binder is phenolic resin, carboxymethyl cellulose and xanthan gum, and the mass ratio of phenolic resin, carboxymethyl cellulose and xanthan gum is 1:1:1.

[0069] The only difference between this embodiment and Embodiment 1 is that:

[0070] (1) Paste preparation: Take 7.92L of 75%wt ethanol solution, add 0.66kg of carboxymethyl cellulose and 0.66kg of xanthan gum and mix evenly. Add 0.66kg of phenolic resin and mix evenly. Then mix evenly with 8kg of graphite anode material to obtain paste.

[0071] In this embodiment, the yield of the raw product is 98%, and the yield of the conductive column material is 87%.

[0072] Example 8: A method for manufacturing a conductive column for a box-type graphitization furnace

[0073] In this embodiment, the binder is phenolic resin, carboxymethyl cellulose, xanthan gum, and starch, and the mass ratio of phenolic resin, carboxymethyl cellulose, xanthan gum, and starch is 1:1:1:1.

[0074] The only difference between this embodiment and Embodiment 1 is that:

[0075] (1) Paste preparation: Take 6.65L of 75%wt ethanol solution, add 0.5kg of carboxymethyl cellulose, 0.5kg of xanthan gum and 0.5kg of starch and mix evenly. Add 0.5kg of phenolic resin and mix evenly. Then mix evenly with 8kg of graphite anode material to obtain paste.

[0076] In this embodiment, the yield rate of the raw product is 98%, and the yield rate of the conductive column material is 88%.

[0077] Example 9: A method for manufacturing a conductive column for a box-type graphitization furnace

[0078] In this embodiment, the binder is phenolic resin, carboxymethyl cellulose, xanthan gum, starch and polyvinyl alcohol, and the mass ratio of phenolic resin, carboxymethyl cellulose, xanthan gum, starch and polyvinyl alcohol is 1:1:1:1:1.

[0079] The only difference between this embodiment and Embodiment 1 is that:

[0080] (1) Paste preparation: Take 8.28L of 75%wt ethanol solution, add 0.4kg of carboxymethyl cellulose, 0.4kg of xanthan gum, 0.4kg of starch and 0.4kg of polyvinyl alcohol and mix evenly. Add 0.4kg of phenolic resin and mix evenly. Then mix evenly with 8kg of graphite anode material to obtain paste.

[0081] In this embodiment, the yield of the raw material is 97%, and the yield of the conductive column material is 89%.

[0082] Examples 10-13

[0083] Examples 10-13 are methods for manufacturing conductive columns for box-type graphitization furnaces. The specific methods are basically the same as those in Example 2, except for the parameter settings. The specific differences are shown in Table 1.

[0084] Table 1. Parameters and yield of raw materials and conductive pillar materials in Examples 10-13

[0085]

[0086]

[0087] Performance testing

[0088] The resistivity of the conductive pillars obtained in Examples 1-13 and commercially available conductive pillars was measured, and the results are shown in Table 2.

[0089] Table 2. Test results of compressive strength, bulk density, and resistivity.

[0090]

[0091] As shown in Table 2, the resistivity of the conductive column prepared by the present invention is lower than that of commercially available conductive columns, indicating that the conductive column prepared by the present invention has better performance than commercially available conductive columns. In addition, the conductive column prepared by the present invention has lower pressure resistance and higher bulk density than commercially available conductive columns, making it easier to grind the conductive column after use.

[0092] Comparative Example 1

[0093] This comparative example illustrates a method for manufacturing a conductive pillar, specifically including the following steps:

[0094] (1) Paste preparation: Take 8 kg of graphite anode material and 2 kg of phenolic resin and mix them evenly to obtain paste.

[0095] (2) Compression molding: After putting the paste into the mold, adjust the vacuum degree to -0.08Mpa, pressurize to 19Mpa at a pressurization rate of 2.5MPa / s, and maintain the pressure for 2min. Then adjust to normal atmospheric pressure, take it out, and obtain the raw product with a yield of 41%.

[0096] (3) Drying: Place the raw product in an oven, set the temperature to 95℃, dry for 54 hours, and then take it out.

[0097] (4) Calcination: The dried raw product is placed in the car bottom furnace and heated in the first stage at a rate of 0.63℃ / h to 300℃. Then, it is heated in the second stage at a rate of 0.9℃ / h to 400℃. Finally, it is heated in the third stage at a rate of 0.5℃ / h to 700℃. The product is then allowed to cool naturally to room temperature and removed to obtain the conductive column material. The yield is 57%.

[0098] (5) Turning: The conductive post material is processed by simple turning to obtain the conductive post.

[0099] Comparative Example 2

[0100] This comparative example illustrates a method for manufacturing a conductive pillar, specifically including the following steps:

[0101] (1) Paste preparation: Take 8 kg of graphite anode material and 2 kg of phenolic resin and mix them evenly to obtain paste.

[0102] (2) Compression molding: After placing the paste into the mold, adjust the vacuum degree to -0.09Mpa, perform the first stage of pressurization, pressurize at a rate of 2.5MPa / s to 13Mpa, perform the second stage of pressurization, pressurize at a rate of 3.5MPa / s to 19Mpa, and maintain the pressure for 2min. Then adjust to normal atmospheric pressure, take it out, and obtain the raw product with a yield of 46%.

[0103] (3) Drying: Place the raw product in an oven, set the temperature to 95℃, dry for 54 hours, and then take it out.

[0104] (4) Calcination: The dried raw product is placed in the car bottom furnace and heated in the first stage at a rate of 0.63℃ / h to 300℃. Then, it is heated in the second stage at a rate of 0.05℃ / h to 400℃. Finally, it is heated in the third stage at a rate of 0.5℃ / h to 700℃. The product is then allowed to cool naturally to room temperature and removed to obtain the conductive column material. The yield is 54%.

[0105] (5) Turning: The conductive post material is processed by simple turning to obtain the conductive post.

[0106] Comparative Example 3

[0107] This comparative example is a method for manufacturing a conductive column. The specific method is basically the same as that in Example 1, except that the vacuum degree of the molding process is the normal atmospheric pressure.

[0108] In this comparative example, the yield of the raw product was 69%, and the yield of the conductive column material was 64%.

[0109] Results Analysis

[0110] The results of step (2) of compression molding in Example 1 and Comparative Examples 1-2 show that when the three-stage pressing is changed to one-stage pressing and two-stage pressing during the compression molding process, the yield of the raw product decreases. This indicates that neither one-stage pressing nor two-stage pressing can effectively release the elastic aftereffect of the paste, resulting in delamination of the raw product. The results of Example 1 and Comparative Example 3 show that reducing the vacuum level of the compression molding environment can effectively improve the yield during the compression molding process. The results of step (4) of calcination in Example 1 and Comparative Examples 1-2 show that during the segmented calcination process, both reducing and increasing the heating rate of the second stage affects the pyrolysis and carbonization of the binder, resulting in cracks.

[0111] Example 13: Application of a conductive column prepared by a method for manufacturing a conductive column for a box-type graphitization furnace.

[0112] This embodiment describes the application of a conductive column prepared by a method for manufacturing conductive columns for box-type graphitization furnaces, as detailed below:

[0113] The conductive columns prepared in Examples 1 to 13 were used in box-type graphitization furnaces. The box-type graphitization furnaces were set to 2500℃ and operated continuously for 50 days. The working status of each box-type graphitization furnace was recorded.

[0114] Statistics show that during the 50 days of continuous operation, all the box-type graphitization furnaces were in normal working condition, and the temperature of each box-type graphitization furnace remained basically stable.

[0115] Take the used conductive pillars mentioned above, grind them into powder, and use them as negative electrode materials.

[0116] The conductive column prepared by the manufacturing method of the box-type graphitization furnace of the present invention can be used as a negative electrode material after one use and simple grinding. In addition, the conductive column can simultaneously graphitize other materials during use, which significantly improves the production capacity of the graphitization furnace.

[0117] It should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can still modify the technical solutions described in the above embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for manufacturing a conductive column for a box-type graphitization furnace, characterized in that, Includes the following steps: The graphite anode material and binder are mixed to obtain a paste; The paste is sequentially molded, dried, calcined, and machined to obtain conductive pillars; The particle size of the graphite anode material is ≤0.045mm; The adhesive is a liquid adhesive and / or a dispersible adhesive; Liquid binders include phenolic resins; The dispersible binder is prepared by dispersing a solid binder in a solvent, wherein the solid binder includes carboxymethyl cellulose, xanthan gum, starch and polyvinyl alcohol; The solvent includes water or an ethanol solution, wherein the ethanol solution contains 25-75% ethanol by mass. The compression molding process uses segmented compression; the calcination process uses segmented heating. The segmented heating includes the following steps performed sequentially: The first stage of heating involves raising the temperature to 300℃ at a rate of 0.1~1.25℃ / h. The second stage involves heating at a rate of 0.1~0.8℃ / h to 301~599℃; The third stage involves heating at a rate of 0.1~1.0℃ / h to 600~800℃; The segmented pressurization includes the following steps performed sequentially: The first stage of pressurization involves increasing the pressure to 8-10 MPa at a rate of 0.1-2 MPa / s. The second stage of pressurization involves increasing the pressure to 11-15 MPa at a rate of 0.1-3 MPa / s. The third stage involves pressurizing at a rate of 0.1 to 5 MPa / s to 16 to 22 MPa and maintaining the pressure for 1 to 3 minutes. The vacuum degree of the compression molding is ≤-0.08MPa.

2. The method for manufacturing a conductive column for a box-type graphitization furnace according to claim 1, characterized in that, The mass ratio of the graphite anode material to the liquid binder is 65~80:35~20.

3. The method for manufacturing the conductive column for a box-type graphitization furnace according to claim 1, characterized in that, The ratio of the graphite anode material, solid binder, and solvent is 65~80 g: 35~20 g: 70~90 mL.

4. The method for manufacturing a conductive column for a box-type graphitization furnace according to any one of claims 1 to 3, characterized in that, The drying temperature is 80~110℃, and the drying time is 36~72h.

5. An application of the conductive column prepared by the manufacturing method of the conductive column for the box-type graphitization furnace according to any one of claims 1 to 4, characterized in that, The conductive pillars are used in a box-type graphitization furnace, and after high-temperature graphitization treatment, they are ground and used as negative electrode materials.

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