Modular multi-layer sagger

Abstract

This utility model belongs to the field of material reaction vessel design, and relates to a combined multi-layer sagger, comprising: a sagger body; the inner wall of the sagger body is provided with at least one annular step, a support plate is provided corresponding to one of the annular steps, the support plate is provided with a vent, the height of the vent is less than the height of the annular step corresponding to the support plate; and a sagger cover. The combined multi-layer sagger proposed in this utility model increases the heat exchange area between the sagger and the material on the horizontal plane, improves the uniformity of the internal temperature of the material, reduces the temperature gradient between the core and the surface, enhances the heat transfer rate between the material and the sagger, and shortens the production cycle.

Description

Technical Field

[0001] This utility model belongs to the field of material reaction vessel design and relates to a combined multi-layer crucible. Background Technology

[0002] When synthesizing lithium-ion cathode materials in a roller kiln using the high-temperature solid-state method, the material needs to be placed in a sagger and driven by rollers through a heating zone, a constant-temperature zone, and a cooling zone. During this process, the material absorbs heat and its temperature rises. When it reaches a certain temperature, complex physical / chemical reactions begin to occur, ultimately generating the desired cathode material. Due to the low thermal conductivity of the reactants, the requirements for the sintering process are very stringent when using a traditional sagger as the sintering container. If too much material is loaded into the sagger, the temperature gradient between the core and the surface will be too large, leading to over-burning on the surface and under-burning inside; if too little material is loaded, the production capacity per unit time will be reduced.

[0003] When the material inside the sagger reaches a certain temperature, the carbon source within it undergoes a decomposition reaction, producing large amounts of gases such as carbon dioxide and water vapor. As these gases rise to the surface of the material, the relative motion between them generates viscous shear stress on the surface. When the resultant force of this viscous shear stress exceeds the material's weight, it carries smaller particles out of the sagger. Some of these particles settle at the kiln bottom and in the heating elements, shortening maintenance cycles and increasing costs.

[0004] According to heat transfer theory, increasing the contact area between the crucible and the material enhances heat transfer within the material, thereby reducing the temperature gradient between the core and the surface, resulting in a more uniform temperature. Therefore, a new type of crucible with increased internal heat transfer area was designed. With a fixed loading capacity, the new crucible reduces the temperature gradient between the core and the upper and lower surfaces, making its internal temperature field more uniform. Utility Model Content

[0005] To ensure uniform internal temperature of the material during sintering and reduce the temperature gradient between the core and surface, a multi-layered sagger was designed to increase the internal heat exchange area. The multi-layered sagger enhances heat exchange between the crucible and the material. The sagger and its accessories must meet conditions such as high thermal conductivity, good stability, and absence of metallic elements like copper and iron, and are made of materials like graphite. Bosses of varying heights are designed on the inner wall of the sagger, and support plates of different specifications are placed on the corresponding bosses, thereby increasing the heat exchange area between the material and the sagger. Several through holes are designed on the support plates, which not only facilitates installation / disassembly but also allows for the rapid discharge of gases generated during material decomposition.

[0006] This utility model proposes a combined multi-layer sagger, comprising:

[0007] Bowl body;

[0008] The inner wall of the bowl is provided with at least one annular step, and a support plate is provided corresponding to one of the annular steps. The support plate is provided with a vent, and the height of the vent is less than the height of the annular step corresponding to the support plate.

[0009] Sagger lid.

[0010] Furthermore, the inner wall of the bowl is provided with multiple annular steps, and the height difference between each annular step is different.

[0011] Furthermore, a gap is provided between at least one side of the support plate and the inner wall.

[0012] Furthermore, the gap does not exceed 2 millimeters.

[0013] Furthermore, the support plate is provided with at least two vents, and the vents are symmetrical about the center of the support plate.

[0014] Furthermore, the bowl and the support plate are made of thermally conductive materials.

[0015] Furthermore, the sagger body is integrally formed by the sagger wall and the sagger bottom.

[0016] Furthermore, the annular step and the support plate are rectangular.

[0017] The beneficial effects of this utility model are as follows:

[0018] This invention proposes a combined multi-layer sagger, which increases the heat exchange area between the sagger and the material on a horizontal plane, improving the uniformity of the internal temperature of the material, reducing the temperature gradient between the core and the surface, enhancing the heat transfer rate between the material and the sagger, and shortening the production cycle. Furthermore, it allows the gas generated by the decomposition of the material to escape evenly from its surface, with a low relative velocity between the two, ensuring that the material is not carried out. The sagger structure adopts a split design, which is simple in structure and easy to manufacture. Attached Figure Description

[0019] Figure 1 These are cross-sectional and top views of the multi-layer sagger in this embodiment.

[0020] Figure 2 These are the sectional view and top view of the bowl body in this embodiment.

[0021] Figure 3 These are the cross-sectional view and top view of the first support plate in this embodiment.

[0022] Figure 4 These are the cross-sectional view and top view of the second support plate in this embodiment.

[0023] Figure 5 These are the sectional view and top view of the sagger cover in this embodiment.

[0024] 1. Sagger body; 2. First support plate; 3. Second support plate; 4. Sagger lid; 1-1. Sagger bottom; 1-2. First boss; 1-3. Second boss; 2-1. First support plate surface; 2-2. First support plate vent hole; 3-1. Second support plate surface; 3-2. Second support plate vent hole. Detailed Implementation

[0025] Exemplary examples of this disclosure will now be described in more detail with reference to the foregoing description. While these embodiments illustrate exemplary embodiments of this disclosure, it should be understood that this disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of this disclosure to those skilled in the art.

[0026] Please refer to Figure 1 , Figure 1 The cross-sectional and top views of the multi-layer sagger of this embodiment are shown. In this embodiment, there are two annular steps and support plates. In other embodiments, the number of annular steps and support plates is the same, or may exceed two. The multi-layer sagger consists of a sagger body 1, a first support plate 2, a second support plate 3, and a sagger cover 4. It ensures the uniformity of the internal temperature of the material during sintering, reduces the temperature gradient between the core and the surface, and increases the internal heat exchange area.

[0027] Please refer to Figure 2 , Figure 2 The structure of the sagger body 1 in this embodiment is illustrated. The sagger body 1 includes a sagger wall and a sagger bottom 1-1. The inner wall of the sagger wall adopts an annular stepped structure, forming a first protrusion 1-2 and a second protrusion 1-3. According to... Figure 2 As can be seen from the top view of the sagger body 1, the sizes of the different protrusions vary, with the protrusions closer to the sagger bottom 1-1 being smaller and the protrusions farther from the sagger bottom 1-1 being larger. In other embodiments, for sagger walls containing a multi-layered annular step structure, the sizes of the protrusions are arranged sequentially, and the height difference between each annular step is different.

[0028] Please refer to Figure 3 , Figure 4 , Figure 3 , Figure 4 The structure of the first support plate 2 and the second support plate 3 is illustrated. Figure 3 For example, Figure 3These are cross-sectional and top views of the first support plate 2. The first support plate 2 includes a first support plate surface 2-1 and first support plate vents 2-2. In this embodiment, the first support plate surface 2-1 is rectangular, and there are four first support plate vents 2-2, which are symmetrical about the center of the plate surface, allowing the gas generated by the decomposition of the carbon source to be smoothly discharged into the upper space. In other embodiments, the shape of the plate surface is adapted to the shape of the annular stepped structure, which is circular, and the shape of the plate surface is also circular. In other embodiments, the number of vents is not less than two, to ensure that during the unloading process, a special device on the robotic arm can be inserted into the vents to facilitate and quickly remove the support plate from the crucible. Figure 4 These are the sectional and top views of the second support plate 3, with details as described above. Figure 3 The content is the same.

[0029] Please refer to Figure 5 , Figure 5 The sagger lid is shown. In this embodiment, the sagger lid is the same size as the opening of the sagger body 1.

[0030] In this embodiment, a method for using a multi-layer sagger containing two support plates is further disclosed.

[0031] Step 1: Place the material to be fired into the bottom 1-1 of the sagger, ensuring that the height of the material is 3-5 mm below the first protrusion 1-2.

[0032] Step 2: Place the first support plate 2 on the first boss 1-2, and then put the appropriate material on the first support plate 2 so that its height is 3-5mm lower than the second boss 1-3.

[0033] Step 3: Place the second support plate 3 on the second boss 1-3, and then put the appropriate material on the second support plate 3 so that its height is 3-5mm lower than the height of the vent hole.

[0034] Step 4: Place the lid 4 of the sagger onto the body 1.

[0035] Step 5: The multi-layered sagger containing the material is fed into the roller kiln for heating.

[0036] When the multi-layer saggers enter the roller kiln, the temperature of the outer surface of the saggers begins to rise under the combined action of the heating rods and the fluid. Due to the special design between the bosses and the support plates, the contact between them is good, and the contact thermal resistance is negligible. Simultaneously, both the saggers and the support plates are made of materials with high thermal conductivity; therefore, it can be approximated that there is no temperature difference between the outer surface of the saggers and the support plates. According to heat transfer theory, in solid-solid heat conduction, the temperature at the contact surface is the same, and as the temperature of the saggers rises, heat enters the material through thermal conduction, and the isothermal surface inside the saggers is approximately parallel to the bottom surface of the saggers.

[0037] When the material reaches its decomposition temperature, the carbon source near its isothermal surface undergoes a decomposition reaction, producing large amounts of water vapor, carbon dioxide, and other gases. Because the material on the support plate is relatively thin, the gas quickly passes through its surface into the upper space, preventing internal accumulation and excessive local pressure. The relative velocity between the gas and the material is very low when the gas flows out of the material surface. According to viscous fluid dynamics, the viscous shear stress exerted by the gas on the material is relatively small, making it difficult to carry the material out of the crucible.

Claims

1. A modular multilayer sagger, characterized in that, include: Bowl body; The inner wall of the bowl is provided with at least one annular step, and a support plate is provided corresponding to one of the annular steps. The support plate is provided with a vent, and the height of the vent is less than the height of the annular step corresponding to the support plate. Sagger lid.

2. The sagger of claim 1, wherein, The inner wall of the bowl is provided with multiple annular steps, and the height difference between each annular step is different.

3. The sagger of claim 1, wherein, The support plate has a gap between at least one side and the inner wall.

4. The sagger of claim 3, wherein, The gap shall not exceed 2 mm.

5. The sagger of claim 1, wherein, The support plate is provided with at least two vents, which are symmetrical about the center of the support plate.

6. The sagger of claim 1, wherein, The bowl and the support plate are made of thermally conductive materials.

7. The sagger of claim 1, wherein, The bowl body is formed by integrally molding the bowl wall and the bowl bottom.

8. The sagger of claim 1, wherein, The annular step and the support plate are rectangular.

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