An apparatus for preparing hard carbon anode materials for sodium-ion batteries using coal tar-based pitch.

Abstract

This invention discloses an apparatus for preparing hard carbon anode materials for sodium-ion batteries using coal tar-based pitch. The apparatus includes a pitch silo, a feeding device, a raw material melting unit, a fractionation and separation unit, a molecular crosslinking modification unit, and a high-temperature carbonization treatment unit. Pitch raw material is fed from the pitch silo into the raw material melting unit via the feeding device, and then transported from the melting unit to the fractionation and separation unit via a pump. From there, it sequentially enters the molecular crosslinking modification unit and the high-temperature carbonization treatment unit through a pipeline. The molecular crosslinking modification unit and the high-temperature carbonization treatment unit integrate pre-oxidation (crosslinking) and high-temperature carbonization into a continuous production line, achieving seamless material flow under a protective atmosphere and avoiding batch instability and performance degradation problems caused by air contact in traditional batch processes. The hard carbon anode material prepared using this equipment achieves high initial coulombic efficiency, excellent rate performance, and long cycle life.

Description

Technical Field

[0001] This utility model relates to the field of sodium-ion battery technology, specifically to a device for preparing hard carbon anode materials for sodium-ion batteries using coal tar-based pitch. Background Technology

[0002] Sodium-ion batteries, as an emerging electrochemical energy storage technology, have shown broad application prospects in large-scale energy storage and low-speed electric vehicles due to their abundant resources and low cost. Among the many components of a sodium-ion battery, the performance of the anode material is one of the key factors determining the overall energy density, cycle life, and cost of the battery. Among numerous candidate materials, hard carbon materials are considered the most promising anode material for sodium-ion batteries due to their abundant sodium storage sites, suitable sodium intercalation potential, and excellent structural stability.

[0003] Currently, the preparation of hard carbon materials mostly uses biomass (such as wood and starch) or synthetic polymers as precursors. However, these precursors often suffer from problems such as dispersed sources, uneven composition, and low carbonization yield, resulting in poor batch stability, large performance fluctuations, and high production costs in the final hard carbon materials, making it difficult to meet the stringent requirements of industrialization for consistency and economy.

[0004] To address these issues, researchers began exploring carbon sources that are widely available, high in carbon content, and cheaper. Coal tar pitch, a byproduct of coal chemical and coking industries, is a promising hard carbon precursor due to its high aromaticity and high carbonization yield. However, direct use of coal tar pitch also has significant drawbacks: First, it is a complex mixture composed of components with a wide molecular weight distribution. Some lighter components (such as wax oil) are easily converted into disordered soft carbon structures during carbonization, leading to low coulombic efficiency and rapid capacity decay. Second, existing technologies often employ simple direct carbonization or intermittent modification-carbonization processes, which are lengthy. Furthermore, during the transfer between processes, the material is highly susceptible to oxidation upon contact with air, introducing impurities and causing significant batch-to-batch quality variations, resulting in unstable product performance. Utility Model Content

[0005] The technical problem to be solved by this utility model is to overcome the existing defects and provide a device for preparing hard carbon anode materials for sodium-ion batteries using coal tar-based pitch. By integrating pre-oxidation and high-temperature carbonization into a continuous production line through a molecular cross-linking modification unit and a high-temperature carbonization treatment unit, the process flow is shortened and seamless material flow under a protective atmosphere is achieved. This avoids the batch instability and performance degradation caused by contact with air in traditional intermittent processes, and can effectively solve the problems in the background technology.

[0006] To achieve the above objectives, this utility model provides the following technical solution: an equipment for preparing hard carbon anode materials for sodium-ion batteries using coal tar-based pitch, comprising a pitch silo, a feeding device, a raw material melting unit, a fraction cutting and separation unit, a molecular crosslinking modification unit, and a high-temperature carbonization treatment unit. The pitch raw material is fed from the pitch silo into the raw material melting unit through the feeding device, and then from the raw material melting unit to the fraction cutting and separation unit through a conveying pump, and then sequentially enters the molecular crosslinking modification unit and the high-temperature carbonization treatment unit through a conveying pipeline.

[0007] As a preferred embodiment of the present invention, the raw material melting unit includes a melting vessel, a heating jacket is provided on the outside of the melting vessel, and a stirring device is provided on the melting vessel.

[0008] As a preferred technical solution of this utility model, the stirring device includes a stirring motor installed at the center of the upper surface of the melting vessel, the output shaft of the stirring motor passing through the melting vessel and connected to the stirring shaft through a coupling, and stirring blades are provided on the stirring shaft.

[0009] As a preferred embodiment of this invention, the melting vessel is connected to the outlet of the inert gas tank A via a gas pipeline.

[0010] As a preferred embodiment of this utility model, the fraction cutting and separation unit includes a solvent extraction tower, a delivery pump connected to the upper inlet of the solvent extraction tower via a pipeline, the lower inlet of the solvent extraction tower connected to a solvent tank via a pipeline, the upper outlet of the solvent extraction tower connected to the inlet of a condenser via a pipeline, the outlet of the condenser connected to a separation tank via a pipeline, and the bottom outlet of the separation tank connected to an external discharge pipe.

[0011] As a preferred embodiment of this invention, the upper outlet of the separation tank is connected to a distillation column, the bottom outlet of the distillation column is connected to a molecular crosslinking modification unit, and the upper outlet of the distillation column is connected to a solvent extraction column.

[0012] As a preferred embodiment of this utility model, the molecular crosslinking modification unit includes a pre-oxidation reactor, which is connected to an oxidation gas tank via a gas pipeline, and the outlet of the pre-oxidation reactor is connected to a high-temperature carbonization treatment unit.

[0013] As a preferred embodiment of the present invention, the high-temperature carbonization treatment unit includes a tubular carbonization furnace, a quartz boat for holding materials is provided inside the tubular carbonization furnace, and a push rod for moving the quartz boat is provided inside the tubular carbonization furnace.

[0014] As a preferred embodiment of this utility model, the tubular carbonization furnace is connected to the outlet of the inert gas tank B via a gas pipeline.

[0015] As a preferred embodiment of this utility model, the outlet of the tubular carbonization furnace is connected to the inlet of the cooling chamber, and the outlet of the cooling chamber is connected to the vacuum sealing machine.

[0016] Compared with existing technologies, the advantages of this invention are as follows: By integrating the fractionation and separation unit, it can actively select high-performance light asphalt components as raw materials, thereby improving the electrochemical performance of the final hard carbon product from the source; simultaneously, by integrating pre-oxidation (crosslinking) and high-temperature carbonization into a continuous production line through the molecular crosslinking modification unit and the high-temperature carbonization treatment unit, the process flow is shortened, and seamless material transfer under a protective atmosphere is achieved, avoiding batch instability and performance degradation caused by air contact in traditional batch processes. The hard carbon anode material prepared by this equipment can achieve high initial coulombic efficiency, excellent rate performance, and long cycle life. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a schematic diagram of the structure of the tubular carbonization furnace of this utility model.

[0018] In the diagram: 1. Asphalt silo, 2. Feeding device, 3. Melting vessel, 4. Stirring device, 5. Inert gas tank A, 6. Transfer pump, 7. Solvent extraction tower, 8. Solvent tank, 9. Condenser, 10. Separation tank, 11. Exhaust pipe, 12. Pre-oxidation reactor, 13. Oxidizing gas tank, 14. Distillation tower, 15. Tubular carbonization furnace, 16. Inert gas tank B, 17. Cooling chamber, 18. Vacuum sealing machine, 19. Quartz boat, 20. Push rod. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0020] Please see Figure 1-2This invention provides a technical solution: an equipment for preparing hard carbon anode materials for sodium-ion batteries using coal tar-based pitch, comprising a pitch silo 1, a feeding device 2, a raw material melting unit, a fractionation and separation unit, a molecular crosslinking modification unit, and a high-temperature carbonization treatment unit. Pitch raw material is fed from the pitch silo 1 into the raw material melting unit via the feeding device 2, and then transported from the raw material melting unit to the fractionation and separation unit via a transfer pump 6. It then sequentially enters the molecular crosslinking modification unit and the high-temperature carbonization treatment unit through a transport pipeline. By integrating the fractionation and separation unit, the equipment can actively select the lighter pitch components with better performance as raw materials, improving the electrochemical performance of the final hard carbon product from the source. Simultaneously, by integrating pre-oxidation (crosslinking) and high-temperature carbonization into a continuous production line through the molecular crosslinking modification unit and the high-temperature carbonization treatment unit, seamless material flow under a protective atmosphere is achieved, avoiding batch instability and performance degradation problems caused by air contact in traditional batch processes. The hard carbon anode material prepared by this equipment is expected to achieve high initial coulombic efficiency, excellent rate performance, and long cycle life.

[0021] The entire equipment is designed for continuous production, which helps to significantly reduce production costs and promote the industrialization of hard carbon anodes for sodium-ion batteries.

[0022] In a preferred embodiment, the raw material melting unit includes a melting vessel 3, with a heating jacket on the outside and a temperature sensor inside, which precisely controls the melting temperature (typically between 200-300°C).

[0023] In the preferred technical solution, the melting kettle 3 is equipped with a stirring device 4 for stirring the asphalt to ensure that the asphalt is heated evenly.

[0024] Optionally, the stirring device 4 includes a stirring motor installed at the center of the upper surface of the melting vessel 3. The output shaft of the stirring motor passes into the melting vessel 3 and is connected to the stirring shaft via a coupling. The stirring shaft is equipped with stirring blades. The stirring motor drives the stirring blades to rotate through the stirring shaft, thereby stirring the asphalt in the melting vessel 3 and improving the melting efficiency.

[0025] In a preferred embodiment, the melting vessel 3 is connected to the outlet of an inert gas tank A5 via a gas pipeline. The inert gas tank A5 is used to establish and protect an inert atmosphere within the melting vessel 3 throughout the process to prevent asphalt oxidation.

[0026] In a preferred embodiment, the fraction cutting and separation unit includes a solvent extraction tower 7, a delivery pump 6 is connected to the upper inlet of the solvent extraction tower 7 via a pipeline, and the lower inlet of the solvent extraction tower 7 is connected to a solvent tank 8 via a pipeline. Liquid asphalt and solvent (such as toluene) come into countercurrent contact in the tower, the light components dissolve in the solvent, and the heavy components settle and separate.

[0027] The upper outlet of the solvent extraction column 7 is connected to the inlet of the condenser 9 via a pipeline. The outlet of the condenser 9 is connected to the separation tank 10 via a pipeline. The solution rich in light components exiting from the top of the solvent extraction column 7 enters the light / heavy component separation tank 10 after being cooled by the condenser 9, where preliminary separation is achieved using density differences. The bottom outlet of the separation tank 10 is connected to the discharge pipe 11 for discharging the heavy components.

[0028] In a preferred embodiment, the upper outlet of the separation tank 10 is connected to the distillation column 14, the bottom outlet of the distillation column 14 is connected to the molecular crosslinking modification unit, and the upper outlet of the distillation column 14 is connected to the solvent extraction column 7. The distillation column 14 evaporates and separates the solvent from the light component, which is then condensed and recycled back into the solvent extraction column 7, reducing production costs. The distillation column 14 ultimately yields pure light component asphalt, which is then transported to the molecular crosslinking modification unit.

[0029] In a preferred embodiment, the molecular crosslinking modification unit includes a pre-oxidation reactor 12, which is preferably a multi-stage cyclone reactor or a fluidized bed reactor to ensure sufficient reaction and continuous production. The pre-oxidation reactor 12 is connected to an oxidizing gas tank 13 via a gas pipeline. The material enters from the top and comes into countercurrent contact with a controlled flow of air / oxidizing gas introduced from the bottom. Inside the reactor, the asphalt material undergoes a crosslinking reaction with the thermal oxidizing gas, gradually transforming from a viscous liquid into a black, brittle solid.

[0030] Optionally, the pre-oxidation reactor 12 is equipped with a multi-segment temperature control system, which allows the cross-linking reaction to proceed smoothly under a precise temperature gradient, forming a stable oxygen bridge cross-linking structure.

[0031] In a preferred embodiment, the outlet of the pre-oxidation reactor 12 is connected to the high-temperature carbonization treatment unit. The reacted solid material is discharged through a screw conveyor at the other end or by gravity and fed into the high-temperature carbonization unit. The high-temperature carbonization treatment unit includes a tubular carbonization furnace 15, the furnace tube of which is made of a high-temperature resistant material such as corundum or quartz. A quartz boat 19 for holding materials is provided inside the tubular carbonization furnace 15, and a pusher 20 for moving the quartz boat 19 is also provided inside the tubular carbonization furnace 15.

[0032] Optionally, the tubular carbonization furnace 15 is divided into multiple independent heating zones, allowing for precise programming and control of the heating curve. The material, within the quartz boat 19, is slowly and continuously traversed through each zone via pusher 20 and a drive mechanism, ensuring complete carbonization and structural stability. The drive mechanism can employ commonly used electric pushers, hydraulic cylinders, or screw drives.

[0033] In a preferred embodiment, the tubular carbonization furnace 15 is connected to the outlet of an inert gas tank B16 via a gas pipeline. The inert gas tank B16 is used to supply high-purity inert gases such as argon, providing full protection for the high-temperature carbonization process.

[0034] Optionally, the outlet of the tubular carbonization furnace 15 is connected to the inlet of the cooling chamber 17, and the outlet of the cooling chamber 17 is connected to the vacuum sealing machine 18. The high-temperature hard carbon after carbonization first enters the cooling chamber 17 and is slowly cooled to room temperature in an environment filled with inert gas to prevent the hot material from oxidizing upon contact with air. The cooled hard carbon powder enters the vacuum sealing machine 18 through a discharge device (such as a vacuum discharger) for direct packaging, ensuring that the product's performance does not degrade during storage and transportation.

[0035] All electronic devices used in this application are powered by an external power source and controlled by an external control switch or controller. The controller is a commonly used PLC controller or microcontroller, and all electronic devices and controllers are commonly used electronic components in the prior art. Their specific structure, working principle, control method and circuit connection are all known technologies and will not be described in detail here.

[0036] The parts not disclosed in this utility model are all prior art, and their specific structures, materials, and working principles will not be described in detail. Although embodiments of this utility model have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of this utility model, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An apparatus for preparing hard carbon anode materials for sodium-ion batteries using coal tar-based pitch, characterized in that: It includes an asphalt silo (1), a feeding device (2), a raw material melting unit, a fraction cutting and separation unit, a molecular crosslinking modification unit, and a high-temperature carbonization treatment unit. The asphalt raw material is fed from the asphalt silo (1) into the raw material melting unit through the feeding device (2), and then from the raw material melting unit to the fraction cutting and separation unit through the conveying pump (6), and then sequentially enters the molecular crosslinking modification unit and the high-temperature carbonization treatment unit through the conveying pipeline.

2. The equipment for preparing hard carbon anode material for sodium-ion batteries using coal tar-based pitch according to claim 1, characterized in that: The raw material melting unit includes a melting kettle (3), a heating jacket is provided on the outside of the melting kettle (3), and a stirring device (4) is provided on the melting kettle (3).

3. The equipment for preparing hard carbon anode material for sodium-ion batteries using coal tar-based pitch according to claim 2, characterized in that: The stirring device (4) includes a stirring motor installed at the center of the upper surface of the melting vessel (3). The output shaft of the stirring motor passes into the melting vessel (3) and is connected to the stirring shaft through a coupling. The stirring shaft is provided with stirring blades.

4. The equipment for preparing sodium-ion battery hard carbon anode material using coal tar-based pitch according to claim 2, characterized in that: The melting vessel (3) is connected to the outlet of the inert gas tank A (5) via a gas pipeline.

5. The equipment for preparing hard carbon anode material for sodium-ion batteries using coal tar-based pitch according to claim 1, characterized in that: The fraction cutting and separation unit includes a solvent extraction tower (7), a delivery pump (6) connected to the upper inlet of the solvent extraction tower (7) via a pipeline, the lower inlet of the solvent extraction tower (7) connected to the solvent tank (8) via a pipeline, the upper outlet of the solvent extraction tower (7) connected to the inlet of the condenser (9) via a pipeline, the outlet of the condenser (9) connected to the separation tank (10) via a pipeline, and the bottom outlet of the separation tank (10) connected to the discharge pipe (11).

6. The equipment for preparing hard carbon anode material for sodium-ion batteries using coal tar-based pitch according to claim 5, characterized in that: The upper outlet of the separation tank (10) is connected to the distillation column (14), the bottom outlet of the distillation column (14) is connected to the molecular crosslinking modification unit, and the upper outlet of the distillation column (14) is connected to the solvent extraction column (7).

7. The equipment for preparing hard carbon anode material for sodium-ion batteries using coal tar-based pitch according to claim 1, characterized in that: The molecular crosslinking modification unit includes a pre-oxidation reactor (12), which is connected to an oxidation gas tank (13) via a gas pipeline, and the outlet of the pre-oxidation reactor (12) is connected to a high-temperature carbonization treatment unit.

8. The equipment for preparing hard carbon anode material for sodium-ion batteries using coal tar-based pitch according to claim 1, characterized in that: The high-temperature carbonization treatment unit includes a tubular carbonization furnace (15), which is equipped with a quartz boat (19) for holding materials, and a push rod (20) for moving the quartz boat (19) is provided inside the tubular carbonization furnace (15).

9. The apparatus for preparing hard carbon anode material for sodium-ion batteries using coal tar-based pitch according to claim 8, characterized in that: The tubular carbonization furnace (15) is connected to the outlet of the inert gas tank B (16) via a gas pipeline.

10. The apparatus for preparing hard carbon anode material for sodium-ion batteries using coal tar-based pitch according to claim 8, characterized in that: The outlet of the tubular carbonization furnace (15) is connected to the inlet of the cooling chamber (17), and the outlet of the cooling chamber (17) is connected to the vacuum sealing machine (18).

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