Thermal cycle low-temperature sintering tunnel kiln
By integrating coating, drying, low-temperature sintering and cooling functions, the thermal cycling low-temperature sintering tunnel kiln solves the problem of uneven coating of lithium-ion battery anode materials, and achieves efficient powder processing and resource conservation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- HENAN TIANMU PILOT BATTERY MATERIALS CO LTD
- Filing Date
- 2025-04-17
- Publication Date
- 2026-05-12
AI Technical Summary
In existing technologies, the coating process for lithium-ion battery anode materials is complex and involves multiple steps, resulting in uneven coating of the powder surface and low efficiency, which cannot meet the requirements of high-capacity and high-power lithium-ion batteries.
Design a thermal circulation low-temperature sintering tunnel kiln that integrates coating, drying, low-temperature sintering and cooling functions, including a coating chamber, a drying chamber, a low-temperature sintering chamber and a cooling chamber, to achieve efficient powder processing through hot gas circulation and nitrogen preheating.
It improved production efficiency, enhanced the quality of powder surface coating, saved resources, ensured sintering effect, and reduced energy waste.
Smart Images
Figure CN224230655U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of tunnel kiln technology, and in particular to a thermal circulation low-temperature sintering tunnel kiln. Background Technology
[0002] Currently, the main anode materials for commercially used lithium-ion batteries are carbon materials, including graphite. However, their theoretical specific capacity is low and cannot meet the requirements of high-capacity, high-power lithium-ion batteries. Therefore, existing technologies employ graphite powder coating to prepare high-capacity, high-power graphite anode materials for lithium-ion batteries that combine energy density and fast-charging performance. The main steps are: dispersing a low-carbon precursor in a solvent, then mixing and drying to deposit the low-carbon precursor onto the surface of graphite powder; then heating and cooling the coated powder under an inert atmosphere to obtain a carbon-coated structure. However, existing technologies involve step-by-step powder coating processes. First, the powder and surface coating agent solution are mixed in an autoclave, then dried in an oven, and finally sintered in a tunnel kiln. These multiple separate operations are not only complex but also affect the coating quality of the powder surface, resulting in problems such as adhesion and uneven coating.
[0003] Therefore, in response to the above problems and technical requirements, it is necessary to design an integrated tunnel kiln that can combine suspension dispersion, drying and sintering, reduce operation steps and powder agglomeration, and at the same time utilize sintering preheating. Summary of the Invention
[0004] The purpose of this utility model is to provide a thermal circulation low-temperature sintering tunnel kiln with a simple structure and strong practicality. It integrates surface coating, drying, low-temperature sintering and cooling functions, which solves the problem of complicated operation of multiple processes in the prior art, and improves production efficiency and coating quality of powder surface.
[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows:
[0006] A thermal circulation low-temperature sintering tunnel kiln includes a coating chamber, a drying chamber, a low-temperature sintering chamber, and a cooling chamber arranged sequentially. The coating chamber is equipped with a feed inlet, a coating agent solution inlet, a stirring vessel, and an inclined filter screen. The drying chamber is equipped with a conveyor belt, a hot gas inlet, and a waste gas outlet. The low-temperature sintering chamber is equipped with a particle processing mechanism, a trolley, and a hot gas outlet. The cooling chamber is equipped with a first nitrogen inlet. The stirring vessel is equipped with a stirring paddle and a discharge port. One end of the inclined filter screen is located below the discharge port, and the other end is located above the conveyor belt. The other end of the conveyor belt is located above the particle processing mechanism. The trolley is located below the particle processing mechanism. The hot gas inlet and the hot gas outlet are connected by a hot gas pipe.
[0007] In this invention, the inclined filter screen refers to a filter screen set at an angle for filtering the coating agent solution. The angled setting facilitates the delivery of the coated powder to the drying chamber. The powder to be sintered is fed into the mixing vessel through the feed inlet, while the coating agent solution is simultaneously delivered through the coating agent solution inlet for powder coating. The stirring paddle is used for stirring, which facilitates contact between the powder and the coating agent solution, improving the coating rate. The coated powder is then conveyed by the inclined filter screen to a conveyor belt for drying, and then conveyed to a particle processing unit for powder processing, removing powder aggregated during the coating process. Finally, the powder is carried by a trolley for sequential sintering and cooling. The hot gas generated during sintering enters the drying chamber through a hot gas pipe, utilizing the residual heat of the hot gas to dry the powder, saving resources and achieving thermal circulation.
[0008] In this invention, nitrogen gas is introduced into the cooling chamber through a first nitrogen inlet, and then into the low-temperature sintering chamber. While cooling the sintered product, the cooling chamber exchanges heat with the nitrogen gas, preheating the nitrogen before it enters the low-temperature sintering chamber. This prevents the direct introduction of nitrogen into the low-temperature sintering chamber from affecting the ambient temperature, effectively ensuring the sintering effect. Furthermore, since the hot gas is mainly located in the low-temperature sintering chamber, this invention introduces nitrogen gas from the tail end of the kiln, i.e., the cooling chamber. This allows the nitrogen gas flow formed within the kiln to move from the product outlet direction to the product inlet direction, facilitating the discharge of hot gas.
[0009] In this invention, the exhaust gas discharged from the exhaust outlet undergoes conventional treatment, such as air purification, to prevent environmental pollution. The trolley is a conventional component of the tunnel kiln, on which a crucible is placed to hold the powder to be sintered. After drying, the powder is processed by a particle processing mechanism and falls into the crucible. Then, the trolley carries it to a low temperature for sintering and cooling to achieve powder coating.
[0010] Preferably, the side wall of the coating chamber is provided with a second nitrogen inlet. The nitrogen gas flow facilitates the rolling off of powder on the inclined filter screen.
[0011] Preferably, a coating agent solution recovery tank is provided below the inclined filter screen. More preferably, the coating agent solution recovery tank is connected to the stirred tank via a circulation pipeline. The coating agent solution recovery tank is used to recover the coating agent solution, and the recovered coating agent solution is then returned to the stirred tank via a conventional circulation pipeline, achieving the reuse of the coating agent solution.
[0012] Furthermore, the particle processing mechanism includes a screen or two opposing pressure rollers. The screen can filter out powder particles that accumulate during the coating process, and the pressure rollers can break up the powder particles, reducing the amount of aggregated powder and achieving full utilization of resources. Preferably, the particle processing mechanism includes two opposing pressure rollers.
[0013] Preferably, the hot gas pipe is equipped with an adsorption plate. The adsorption plate is a commercially available product, such as a conventional activated carbon plate, used to adsorb the sintering products of the coating agent, making the hot gas entering the drying chamber relatively clean and reducing the adverse effects of the hot gas on the powder surface. In practical applications, the adsorption plate is replaced periodically.
[0014] Preferably, isolation gates are provided between the coating chamber and the drying chamber, and between the drying chamber and the low-temperature sintering chamber. Further, when an isolation gate is provided between the coating chamber and the drying chamber, one end of the inclined filter screen passes through the isolation gate and is located above the conveyor belt; when an isolation gate is provided between the drying chamber and the low-temperature sintering chamber, one end of the conveyor belt passes through the isolation gate and is located above the particle processing mechanism. The isolation gates between the coating chamber and the drying chamber, and between the drying chamber and the low-temperature sintering chamber, can be conventional upper and lower structure gates to facilitate the installation of the inclined filter screen and the conveyor belt, while not affecting the normal opening and closing of the isolation gates. The specific installation method and usage of the isolation gates are conventional techniques.
[0015] In practical applications, the inclined filter screen can be a conventional folded edge structure, and baffles can be installed on the side of the conveyor belt to prevent powder from falling during the conveying process.
[0016] Furthermore, an isolation gate may or may not be provided between the low-temperature sintering chamber and the cooling chamber. When an isolation gate is provided between the low-temperature sintering chamber and the cooling chamber, a nitrogen transmission port is provided on the inner wall at the junction of the two chambers. As is common knowledge, the inner wall refers to the inner wall of the kiln body. When an isolation gate is provided between the low-temperature sintering chamber and the cooling chamber, this isolation gate can be a conventional integrated gate structure. Nitrogen gas in the cooling chamber enters the low-temperature sintering chamber through the nitrogen transmission port, facilitating the installation of the isolation gate without affecting its normal opening and closing. Preferably, no isolation gate is provided between the low-temperature sintering chamber and the cooling chamber.
[0017] As is common knowledge, the thermal circulation low-temperature sintering tunnel kiln also includes the conventional structure of a conventional tunnel kiln, such as electrical mechanisms and sealing mechanisms. Conventional pumps or fans are conventionally installed on water pipelines and gas pipelines, which does not affect the understanding of the technological progress of this utility model by those skilled in the art.
[0018] Due to the application of the above technical solution, the thermal circulation low-temperature sintering tunnel kiln of this utility model has the following advantages:
[0019] (1) This utility model integrates surface coating, drying, low-temperature sintering and cooling functions, which solves the problem of complex operation of multiple processes in the existing process, improves production efficiency, and avoids energy waste and saves resources by recovering and utilizing the heat generated in the low-temperature sintering chamber. It is highly practical.
[0020] (2) By setting up a particle handling mechanism at the end of the conveyor belt to screen the dried powder, it is beneficial to reduce the amount of aggregated powder.
[0021] (3) The nitrogen gas of this utility model is introduced from the product outlet of the tunnel kiln and blown towards the product inlet, which avoids the sintering hot gas from dissipating into the cooling chamber and forms a nitrogen-hot gas passage, which is conducive to the discharge of hot gas. At the same time, the cooling chamber can preheat the nitrogen gas, which avoids the nitrogen gas from being directly introduced into the low temperature sintering chamber and affecting the ambient temperature, thus effectively ensuring the sintering effect.
[0022] (4) The sintering flue gas is adsorbed and then passed into the drying chamber for drying, which makes better use of the residual heat and reduces the adverse effects of the hot gas on the surface of the powder. Attached Figure Description
[0023] Figure 1 This is a schematic diagram of the structure of the thermal cycling low-temperature sintering tunnel kiln in Example 1.
[0024] Figure 2 This is a schematic diagram of the inclined filter screen structure in Example 1.
[0025] Figure 3 This is a schematic diagram of the structure of the thermal cycling low-temperature sintering tunnel kiln in Example 2.
[0026] Figure 4 This is a schematic diagram of the structure of the thermal cycling low-temperature sintering tunnel kiln in Example 3.
[0027] Figure 5 This is a schematic diagram of the structure of the thermal cycling low-temperature sintering tunnel kiln in Example 4.
[0028] Figure 6 This is a schematic diagram of the low-temperature sintering chamber and cooling chamber in Example 4.
[0029] The components include: coating chamber 1, drying chamber 2, low-temperature sintering chamber 3, cooling chamber 4, hot gas pipe 5, activated carbon plate 6, isolation gate 7, outlet gate 8, circulation pipeline 9, nitrogen transmission port 10, feed port 101, coating agent solution inlet 102, stirring tank 103, inclined filter screen 104, second nitrogen inlet 105, coating agent solution recovery tank 106, conveyor belt 201, hot gas inlet 202, waste gas outlet 203, particle processing mechanism 301, trolley 302, hot gas outlet 303, first nitrogen inlet 401, stirring paddle 1031, and discharge port 1032. Detailed Implementation
[0030] The technical solution of this utility model will be clearly and completely described below with reference to the accompanying drawings and preferred embodiments. All components in this utility model are existing products, and the specific connection and control methods are conventional technologies. The tilt angle and aperture size of the inclined filter screen and the aperture size of the screen are not specifically limited, and can be selected as needed, as long as the graphite powder falling on the inclined filter screen rolls onto the conveyor belt and the coating agent solution is filtered out at the same time, and the screen can remove the aggregated graphite powder. The pressure roller is a conventional crushing device, and its use method is conventional technology. The two rollers have a small gap, which plays a role in breaking up aggregated particles. The pipeline is conventionally equipped with valves (powder, liquid, etc.) and fans (gas circulation).
[0031] Taking the coating of low-temperature (500-600℃) sintered graphite powder as an example, in this invention, the graphite powder to be sintered sequentially passes through a coating chamber, a drying chamber, a low-temperature sintering chamber, and a cooling chamber. The coating chamber is used to coat the graphite powder; the drying chamber is used to dry the coated graphite powder; and the low-temperature sintering chamber is used to sinter the graphite powder. The hot gas generated during sintering enters the drying chamber through a hot gas pipe, utilizing the residual heat of the hot gas to dry the graphite powder. Nitrogen gas is introduced into the cooling chamber through a first nitrogen inlet, and then into the low-temperature sintering chamber. While cooling the sintered product, the cooling chamber exchanges heat with the nitrogen gas, preheating the nitrogen gas before it enters the low-temperature sintering chamber. This prevents the nitrogen gas from directly entering the low-temperature sintering chamber and affecting the ambient temperature, effectively ensuring the sintering effect. The coating agent solution used in this embodiment is a sucrose solution, obtained by dissolving 1 kg of sucrose in 200 kg of deionized water.
[0032] 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 invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. For example, terms such as "length," "width," "upper," "lower," "vertical," "horizontal," "top," "bottom," "inner," and "outer" indicate orientations or positions based on the accompanying drawings and are for ease of description only, and should not be construed as limiting the scope of the invention. In this invention, powder is fed into a coating chamber and discharged from a cooling chamber. Example 1
[0033] like Figures 1 to 2 As shown:
[0034] A thermal circulation low-temperature sintering tunnel kiln includes a coating chamber 1, a drying chamber 2, a low-temperature sintering chamber 3, and a cooling chamber 4 arranged sequentially.
[0035] The coating chamber includes a feed inlet 101, a coating agent solution inlet 102, a stirring vessel 103, and an inclined filter screen 104; the drying chamber includes a conveyor belt 201, a hot gas inlet 202, and a waste gas outlet 203; the low-temperature sintering chamber includes a particle processing mechanism 301, a trolley 302, and a hot gas outlet 303; and the cooling chamber includes a first nitrogen inlet 401. The stirring vessel includes a stirring paddle 1031 and a discharge port 1032; the inclined filter screen is a commercially available product, configured with a folded edge structure using conventional methods (except for the end above the conveyor belt, the edges of the remaining surfaces are folded upwards, see [reference]). Figure 2 The device serves to block the powder, with one end located below the discharge port and the other end above the conveyor belt; the other end of the conveyor belt is located above the granulation processing mechanism; the trolley is located below the granulation processing mechanism; the hot air inlet and hot air outlet are connected by a hot air pipe 5. Additionally, those skilled in the art can, as needed, install baffles on the side of the conveyor belt to prevent powder from falling off.
[0036] In this embodiment, the side wall of the covering chamber is provided with a second nitrogen inlet 105.
[0037] In this embodiment, a coating agent solution recovery tank 106 is provided below the inclined filter screen.
[0038] In this embodiment, the particle processing mechanism includes two pressure rollers arranged opposite each other.
[0039] In this embodiment, an activated carbon plate 6 is installed inside the hot air pipe. In practical applications, the activated carbon plate is fixed inside the hot air pipe using conventional fasteners, such as bolts.
[0040] In this embodiment, isolation gates 7 are provided between the coating chamber and the drying chamber, and between the drying chamber and the low-temperature sintering chamber. No isolation gate is provided between the low-temperature sintering chamber and the cooling chamber. The single line in the figure represents the boundary between two adjacent chambers. One end of the inclined filter screen passes through the isolation gate between the coating chamber and the drying chamber and is located above the conveyor belt; the other end of the conveyor belt passes through the isolation gate between the drying chamber and the low-temperature sintering chamber and is located above the particle processing mechanism. These isolation gates are conventional vertical structures, and their installation and usage methods are conventional techniques.
[0041] The thermal circulation low-temperature sintering tunnel kiln is also equipped with a conventional outlet gate 8. The outlet gate is a conventional integrated structure gate, and the specific installation method and usage method are conventional technologies.
[0042] In this invention, the exhaust gas discharged from the exhaust outlet undergoes conventional treatment, such as air purification, to prevent environmental pollution. The trolley is a conventional component of the tunnel kiln, on which a crucible is placed to hold the powder to be sintered. After drying, the powder is processed by a particle processing mechanism and falls into the crucible. Then, the trolley carries it to a low temperature for sintering and cooling to achieve powder coating.
[0043] As is common knowledge, the aforementioned thermal circulation low-temperature sintering tunnel kiln also includes the conventional structure of a conventional tunnel kiln, such as electrical mechanisms and sealing mechanisms. Conventional pumps or fans are conventionally installed on water pipelines and gas pipelines, which does not affect the understanding of the technological progress of this utility model by those skilled in the art. The size of the crucible opening on the trolley is greater than the width of the pressure roller, the width of the pressure roller is greater than the width of the conveyor belt, and the width of the conveyor belt is greater than the width of the inclined filter screen. The specific width is designed according to needs, as long as it can receive the graphite powder sent from the previous process.
[0044] The thermal circulation low-temperature sintering tunnel kiln of this embodiment, taking the coating of low-temperature sintered graphite oxide powder as an example, is used as follows:
[0045] (1) The sintered graphite powder and the coating agent solution are fed into the mixing tank through the feed port and the coating agent solution inlet, respectively, and stirred for 2 hours;
[0046] (2) Open the discharge port, and the coated graphite powder falls onto the inclined filter screen, and then onto the conveyor belt of the drying chamber. It is dried by the hot air transported by the low temperature sintering chamber. The coating agent solution is recovered into the coating agent solution recovery tank through the inclined filter screen.
[0047] (3) The coated and dried graphite powder is sent to the low temperature sintering chamber and falls from the conveyor belt into the pressure roller. The aggregates are broken and then fall into the crucible on the trolley. The low temperature calcination is carried out at 550℃ for 3 hours. The tail nitrogen gas is blown from the cooling chamber to the low temperature sintering chamber. The sintering hot gas is passed through the hot gas outlet and the hot gas pipe is adsorbed and then passed into the drying chamber.
[0048] (4) The coated, dried, and sintered graphite powder is carried by a trolley into the cooling chamber for conventional cooling. After heat exchange with nitrogen gas, it is introduced into the low-temperature sintering chamber to complete the coating and low-temperature sintering of the graphite powder. Example 2
[0049] Based on Example 1, the difference in this example is that the coating agent solution recovery tank is connected to the stirred tank via circulation pipe 9; otherwise, it is the same. See [link to example]. Figure 3 The coating agent solution can be reused. Example 3
[0050] Based on Example 1, the difference in this example is that the two opposing pressure rollers are replaced with screens; otherwise, they are the same. See [link to example]. Figure 4 This allows for control over the size of the powder falling into the crucible. Additionally, those skilled in the art can, as needed, install baffles around the sieve to prevent powder from falling out. Example 4
[0051] Based on Embodiment 1, the difference in this embodiment is that an isolation gate is provided between the low-temperature sintering chamber and the cooling chamber, and a nitrogen transmission port 10 is provided on the inner wall at the junction of the low-temperature sintering chamber and the cooling chamber. The rest is the same. Figures 5 to 6 As shown, nitrogen enters from the cooling chamber and is blown into the low-temperature sintering chamber through the nitrogen transfer port. As is common knowledge, the inner wall refers to the inner wall of the kiln body; this isolation gate is a conventional integrated structure gate, and its specific installation and usage methods are conventional techniques.
[0052] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the principle of the present utility model, and these should also be considered to fall within the protection scope of the present utility model.
Claims
1. A thermally circulating low-temperature sintering tunnel kiln, characterized in that: The apparatus includes a coating chamber, a drying chamber, a low-temperature sintering chamber, and a cooling chamber arranged sequentially. The coating chamber is equipped with a feed inlet, a coating agent solution inlet, a stirring vessel, and an inclined water filter. The drying chamber is equipped with a conveyor belt, a hot gas inlet, and a waste gas outlet. The low-temperature sintering chamber is equipped with a particle processing mechanism, a trolley, and a hot gas outlet. The cooling chamber is equipped with a first nitrogen inlet. The stirring vessel is equipped with a stirring paddle and a discharge port. One end of the inclined water filter is located below the discharge port, and the other end is located above the conveyor belt. The other end of the conveyor belt is located above the particle processing mechanism. The trolley is located below the particle processing mechanism. The hot gas inlet and hot gas outlet are connected by a hot gas pipe.
2. The thermal circulation low-temperature sintering tunnel kiln according to claim 1, characterized in that: The side wall of the encapsulation chamber is provided with a second nitrogen inlet.
3. The thermal circulation low-temperature sintering tunnel kiln according to claim 1, characterized in that: Below the inclined filter screen is a coating agent solution recovery tank.
4. The thermal circulation low-temperature sintering tunnel kiln according to claim 3, characterized in that: The coating agent solution recovery tank is connected to the stirred tank via a circulation pipeline.
5. The thermal circulation low-temperature sintering tunnel kiln according to claim 1, characterized in that: The particle processing mechanism includes a screen or two opposing pressure rollers.
6. The thermal circulation low-temperature sintering tunnel kiln according to claim 1, characterized in that: An adsorption plate is installed inside the hot air pipe.
7. The thermal circulation low-temperature sintering tunnel kiln according to claim 1, characterized in that: Isolation gates are provided between the coating chamber and the drying chamber, and between the drying chamber and the low-temperature sintering chamber.
8. The thermal circulation low-temperature sintering tunnel kiln according to claim 7, characterized in that: One end of the inclined filter screen passes through the isolation gate and is located above the conveyor belt.
9. The thermal circulation low-temperature sintering tunnel kiln according to claim 7, characterized in that: One end of the conveyor belt passes through the isolation gate and is located above the particle processing mechanism.
10. The thermal circulation low-temperature sintering tunnel kiln according to claim 1, characterized in that: The low-temperature sintering chamber and the cooling chamber may or may not be equipped with an isolation gate; when an isolation gate is provided between the low-temperature sintering chamber and the cooling chamber, a nitrogen transmission port is provided on the inner wall at the junction of the low-temperature sintering chamber and the cooling chamber.