A sagger

Abstract

The utility model discloses a kind of sagger, including bottom wall, multiple side walls and ventilation component, the bottom end of multiple side walls is connected with the side of bottom wall respectively, bottom wall and multiple side walls are enclosed to form the containing cavity for containing powder, flow air duct is set in side wall, and flow air duct in adjacent two side walls is interconnected;Ventilation component includes air vent, first air vent is set on the outer wall of side wall, second air vent is set on the inner wall of side wall, and first air vent and second air vent are communicated with flow air duct.The sagger provided by the utility model, by the flow air duct communicated between each side wall, the furnace gas entering sagger can be mixed in flow air duct first and enter containing cavity along second air vent, improve the atmosphere uniformity of powder in the inside of containing cavity in circumferential direction, and powder sintering is more uniform.

Description

Technical Field

[0001] This utility model relates to the field of sagger manufacturing technology, and specifically to a sagger. Background Technology

[0002] A sagger is a firing vessel widely used in the high-temperature processing of powder materials, typically made of high-temperature resistant and chemically corrosion-resistant ceramic materials. Its main function is to hold powder materials during sintering or calcination, ensuring the materials maintain a relatively stable geometric shape within the high-temperature furnace and preventing direct contact with the furnace lining to avoid contamination. In the large-scale heat treatment processes of lithium-ion batteries, sodium-ion batteries, and other energy storage materials, saggers are indispensable basic equipment. Saggers are usually made of high-temperature resistant ceramic materials such as mullite and corundum to maintain powder stability, isolate impurities, and withstand prolonged high temperatures. With the continuous development of lithium-ion and sodium-ion battery materials towards higher consistency and higher reactivity, the atmosphere penetration capacity, powder retention capacity, and anti-sticking properties of the sagger have a significant impact on sintering quality.

[0003] The existing sagger consists of a bottom wall and four side walls. The four side walls surround the top surface of the bottom wall to form a receiving cavity. Air inlets are opened on both the bottom and side walls, allowing furnace gas to enter the sagger. In actual kiln operation, due to uneven airflow distribution within the kiln and differences in the placement of the saggers, the flow velocity and flow rate of furnace gas on different side walls of the sagger are often inconsistent. This causes one side wall of the sagger to become the main air-receiving side, with a significantly larger air intake than other side walls. This results in differences in the atmosphere state of the powder inside the sagger in different directions, leading to uneven atmosphere distribution and uneven sintering during the sintering process. Utility Model Content

[0004] This invention provides a sagger to solve the problem of uneven atmosphere distribution and uneven sintering of powder in different directions.

[0005] In a first aspect, this utility model provides a sagger, comprising: bottom wall; Multiple sidewalls, the bottom ends of the multiple sidewalls are respectively connected to the side of the bottom wall, the bottom wall and the multiple sidewalls together form a receiving cavity for holding powder, the sidewalls are provided with flow channels, and the flow channels in two adjacent sidewalls are interconnected. A ventilation assembly, comprising: a ventilation port, a first ventilation port being provided on the outer wall of the sidewall, and a second ventilation port being provided on the inner wall of the sidewall, wherein the first ventilation port and the second ventilation port are connected to the airflow duct.

[0006] In one optional embodiment, both the first vent and the second vent are equipped with vent windows, or only the second vent is equipped with the vent window.

[0007] In one alternative implementation, the first ventilation window and the second ventilation window are positioned opposite each other.

[0008] In one alternative embodiment, a breathable powder-blocking layer is provided on the side of the second vent window away from the receiving cavity, the breathable powder-blocking layer being adapted to prevent powder in the receiving cavity from entering the flow channel.

[0009] Beneficial effects When the furnace gas replenishes the atmosphere into the containment cavity through the second ventilation window, the permeable powder barrier layer can effectively prevent powder particles in the containment cavity from entering the flow channel or the outer space of the sagger while allowing the gas to pass through smoothly, thereby reducing the pollution of the flow channel and the kiln lining by the powder.

[0010] In one optional embodiment, the average pore size of the breathable powder barrier layer is smaller than the average particle size of the powder, and the average pore size is less than or equal to 1 μm.

[0011] In one alternative embodiment, the air-permeable barrier layer is sintered from one or more of porous alumina, porous magnesium oxide, porous spinel, and porous zircon.

[0012] In one alternative embodiment, the top surface of the bottom wall is provided with a honeycomb array texture structure.

[0013] In one alternative embodiment, the inner wall of the receiving cavity is coated with a high-temperature anti-stick coating.

[0014] In one alternative embodiment, a groove is provided at the top of the sidewall.

[0015] In one alternative embodiment, the matrix material of the bottom wall and the side wall includes one or more of mullite, cordierite, and mollite, and the bottom wall and the side wall are integrally formed by ceramic sintering process.

[0016] The beneficial effects of this utility model are as follows: The sagger provided by this invention allows for the initial intake of a larger volume of air into the kiln when uneven airflow distribution causes the furnace gas to flow primarily from one side wall. Simultaneously, the airflow from that side is guided circumferentially through the airflow channels to other side walls, ensuring continuous airflow within these channels. This diffuses the locally concentrated airflow to other side walls, achieving a more balanced circumferential airflow within the sagger. The airflow channels significantly reduce the differences in airflow between different side walls, resulting in a more consistent atmosphere supply to the powder inside the sagger in multiple directions and reducing sintering unevenness caused by localized atmosphere deviations. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of a sagger according to an embodiment of the present utility model; Figure 2 This is a front view of a sagger according to an embodiment of the present utility model; Figure 3 A cross-sectional view of a sagger according to an embodiment of this utility model; Figure 4 for Figure 3 A magnified view of part B in the diagram; Figure 5 This is a top view of a sagger according to an embodiment of the present utility model.

[0019] Explanation of reference numerals in the attached figures: 1. Bottom wall; 2. Side walls; 21. Airflow ducts; 31. First ventilation window; 32. Second ventilation window; 4. Breathable powder-resistant layer; 5. Honeycomb array texture structure; 6. Groove. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0021] The following is combined with Figures 1 to 5 The following describes embodiments of the present invention.

[0022] According to an embodiment of the present invention, a sagger is provided, comprising: a bottom wall 1, a plurality of side walls 2, and a ventilation assembly. The bottom ends of the plurality of side walls 2 are respectively connected to the sides of the bottom wall 1. The bottom wall 1 and the plurality of side walls 2 together form a receiving cavity for holding powder. A flow channel 21 is provided in the side wall 2, and the flow channels 21 in adjacent side walls 2 are interconnected. The ventilation assembly comprises: a vent, a first vent is provided on the outer wall of the side wall 2, and a second vent is provided on the inner wall of the side wall 2, and the first vent and the second vent are connected to the flow channel 21.

[0023] The bottom ends of multiple side walls 2 are fixedly connected to the periphery of the bottom wall 1. In this embodiment, four side walls 2 are provided. The sagger is molded and then sintered as a whole, so that the bottom wall 1 and each side wall 2 are firmly connected to form a cavity for holding powder. The height and lateral dimensions of the sagger are determined according to the powder loading and sintering process requirements to ensure that the sagger has sufficient loading volume without excessively occupying the furnace space. In this embodiment, the dimensions of the sagger are: length 330mm × width 330mm × height 90mm.

[0024] The interior of the side wall 2 is provided with flow channels 21, each of which consists of several interconnected through-hole sections, formed by demolding during the side wall 2 forming stage. A first vent is provided on the outer wall of the side wall 2, and a second vent is provided on the inner wall of the side wall 2. The first vent extends along the thickness direction of the side wall 2 into the flow channels 21, connecting the flow channels 21 with the furnace gas space outside the sagger; the second vent extends along the thickness direction of the side wall 2 into the receiving cavity, connecting the flow channels 21 with the receiving cavity. The first and second vents can be arranged at different heights, or they can be arranged opposite each other at the same height.

[0025] After the sagger is placed in the kiln, the kiln gas is affected by the fan and the kiln structure, forming an airflow on the outside of the sagger. When the kiln gas passes the outer surface of the sagger, a small portion of the gas directly enters the receiving cavity through the first and second vents, while most of the gas enters the flow channel 21 through the first vent and flows circumferentially along the sagger. Since the flow channels 21 are interconnected circumferentially, when the gas velocity and intake volume are relatively high near a certain side wall 2, the gas entering the flow channel 21 of that side wall 2 can be transferred to other side walls 2 along the flow channel 21. Meanwhile, the furnace gas entering through the first vent of other side walls 2 will also circulate in the flow channel 21. The furnace gas entering through the first vent of each side wall 2 will be mixed and buffered in the flow channel 21, reducing the difference in atmosphere conditions between different side walls 2. This prevents the furnace gas from being concentratedly blown into the containment cavity from one side and affecting the sintering of the powder. As a result, the powder inside the sagger can obtain a more uniform atmosphere environment in the circumferential direction during the sintering process, reducing the sintering inconsistency caused by uneven atmosphere distribution.

[0026] In one embodiment, both the first vent and the second vent are equipped with vent windows, or only the second vent is equipped with a vent window.

[0027] Specifically, the first ventilation window 31 and the second ventilation window 32 are plate-shaped components, with their outer dimensions slightly larger than the opening dimensions of the first and second ventilation ports. The periphery of the ventilation window fits into the ventilation port and is fixed to the outer wall of the side wall 2 with a high-temperature resistant adhesive. The ventilation windows can be made of stainless steel perforated plate, heat-resistant alloy perforated plate, or perforated ceramic plate to meet the high temperature and furnace gas corrosion requirements during kiln operation.

[0028] In one embodiment, the first ventilation window 31 and the second ventilation window 32 are positioned opposite each other.

[0029] Specifically, the first ventilation window 31 and the second ventilation window 32 are arranged opposite each other along the thickness direction of the same side wall 2, and the center position of the first ventilation window 31 is aligned with the center position of the corresponding second ventilation window 32 along the thickness direction of the side wall 2. When the furnace gas from outside the kiln enters the first ventilation port from a certain side wall 2, after the gas passes through the first ventilation window 31 and enters the flow channel 21, since the second ventilation window 32 is arranged opposite to the first ventilation window 31, a small portion of the gas will directly enter the receiving cavity from the second ventilation window 32, and the remaining gas will flow circumferentially along the flow channel 21 and mix thoroughly with the gas entering from other side walls 2.

[0030] In one embodiment, a breathable powder-blocking layer 4 is provided on the side of the second vent 32 away from the receiving cavity, and the breathable powder-blocking layer 4 is adapted to prevent the powder in the receiving cavity from entering the flow duct 21.

[0031] Specifically, the permeable powder-blocking layer 4 has a plate-like structure, and its thickness is selected according to the pressure difference and gas flow rate inside the furnace during the use of the sagger, ensuring sufficient rigidity while allowing the furnace gas to pass smoothly. The permeable powder-blocking layer 4 has a large number of micropores inside, giving it both good air permeability and the ability to block powder particles from passing through. The permeable powder-blocking layer 4 can be a single-layer structure or a two-layer or multi-layer stacked structure, and multiple layers of permeable powder-blocking layers 4 can be set to enhance the powder blocking effect. When the powder in the receiving cavity has a slight tendency to be lifted or flow back during the filling, compaction or sintering process, even if the powder particles approach the second vent 32, they will be blocked by the permeable powder-blocking layer 4 arranged on its back, making it difficult for them to pass through the permeable powder-blocking layer 4 into the flow channel 21 and the outer space of the sagger.

[0032] In one embodiment, the average pore size of the breathable powder barrier layer 4 is smaller than the average particle size of the powder, and the average pore size is less than or equal to 1 μm.

[0033] The permeable powder-blocking layer 4 is obtained by high-temperature sintering of a porous green body. Its pore size distribution is preferably controlled within the range of 0.05μm to 1μm, and the average pore size value is calculated by mercury intrusion spectroscopy or gas permeation testing to ensure that the average pore size is always smaller than the average particle size of the powder. Since the average pore size of the permeable powder-blocking layer 4 is significantly smaller than the average particle size of the powder, when the powder in the containment cavity generates slight dust and flow during filling, compaction, or heating, even if the powder particles are close to the second ventilation window 32, they are unlikely to pass through the channels with an average pore size ≤1μm and enter the interior of the permeable powder-blocking layer 4, effectively preventing the powder particles from flowing into the flow channel 21 and the kiln space.

[0034] In one embodiment, the air-permeable barrier layer 4 is sintered from one or more of porous alumina, porous magnesium oxide, porous spinel, and porous zircon.

[0035] Specifically, the permeable powder barrier layer 4 is made of alumina powder, magnesium oxide powder, spinel powder, and zircon powder, which are mixed in a certain proportion, and then an organic binder and a pore-forming agent are added. After being mixed evenly in a ball mill, the mixture is pressed into a plate-shaped green body. After the green body is dried, it is sintered in a high-temperature kiln. During the sintering process, the pore-forming agent decomposes or is burned off to form through pores, thereby obtaining a porous ceramic plate with a predetermined porosity and average pore size, namely the permeable powder barrier layer 4. Depending on the kiln operating temperature and atmosphere conditions, porous alumina or porous magnesium oxide can be used alone, or porous spinel and porous zircon can be used in combination to make the permeable powder barrier layer 4 take into account both high-temperature strength and thermal shock resistance.

[0036] In one embodiment, the top surface of the bottom wall 1 is provided with a honeycomb array texture structure.

[0037] Specifically, the top surface of the bottom wall 1 is formed with several recessed units through a compression molding process. These recessed units are arranged in a regular hexagonal array on the plane, resulting in a continuous honeycomb texture area on the entire top surface of the bottom wall 1. The tiny gaps between the honeycomb recesses and the micro-cavities formed inside the recesses help improve the atmosphere distribution at the bottom of the powder, reduce the risk of insufficient sintering or excessive local bonding of the powder at the bottom, and thus improve the overall sintering quality of the powder.

[0038] In one embodiment, the inner wall of the receiving cavity is coated with a high-temperature anti-stick coating.

[0039] Specifically, a high-temperature anti-stick coating covers the top surface of the bottom wall 1 and the inner wall surfaces of each side wall 2 facing the receiving cavity, forming an anti-stick interface in the area where the powder contacts the sagger during filling and sintering. The thickness of the high-temperature anti-stick coating is between 50-100 μm. Preferably, the inner wall of the sagger can be polished and dust-removed before applying the high-temperature anti-stick coating to give the inner wall surface suitable roughness and cleanliness, thereby improving the adhesion and long-term stability of the coating. The high-temperature anti-stick coating can be a high-temperature resistant coating containing alumina, zirconium oxide, silicon nitride, boron nitride, or yttrium oxide fillers, applied to the inner wall of the sagger after sintering by spraying, brushing, or dipping, and then dried and cured by secondary sintering to form a dense and firmly adhered anti-stick coating.

[0040] In one embodiment, a groove 6 is provided at the top of the sidewall 2.

[0041] Specifically, the opening of the groove 6 faces upwards, and the bottom of the groove 6 is lower than the highest point of the top of the side wall 2, giving the top of the side wall 2 a stepped profile. The sagger needs to be frequently loaded, unloaded and moved from the kiln car, so the groove 6 at the top of the side wall 2 can serve as a reliable gripping point or clamping and positioning part, so that the sagger can obtain good gripping stability under different handling methods such as manual holding, robotic arm clamping, and forklift-assisted operation.

[0042] In one embodiment, the matrix material of the bottom wall 1 and the side wall 2 includes one or more of mullite, cordierite, and mollite, and the bottom wall 1 and the side wall 2 are integrally formed by ceramic sintering process.

[0043] Specifically, the bottom wall 1 and side walls 2 can be made primarily from mullite ceramic powder, cordierite ceramic powder, and / or mullite ceramic powder. These are mixed according to the required ratios for thermal expansion properties, thermal shock resistance, and high-temperature strength. Appropriate amounts of binder, lubricant, and molding aids are added, and the mixture is ball-milled until homogeneous to prepare a plastic clay or fluid slurry. The prepared clay is then molded into a green body with an integral structure of bottom wall 1 and side walls 2 using methods such as molding, slip casting, or isostatic pressing. After drying, the green body is placed in a high-temperature kiln and sintered according to a predetermined heating curve. This process causes the ceramic particles inside the green body to sinter and densify, and undergo a crystal phase transformation, ultimately resulting in a sagger with bottom wall 1 and side walls 2 sintered as a single unit.

[0044] Production process: Aggregate preparation: Mullite, cordierite and mullite are mixed in a relative mass ratio of (0-8):(0-3):1 to obtain aggregate; Preparation of the base material: Alumina powder, zircon sand, magnesite powder and quartz powder are mixed in a relative mass ratio of (1-2):1:1:1 to obtain the base material; Preparation of slurry: Water, base material and binder are placed in a mixing device and thoroughly mixed in a relative mass ratio of 25:(8-10):1 to obtain a uniform slurry; Preparation of mud: The slurry and aggregate are mixed in a relative mass ratio of (1.2-4):1, and then processed by a kneader and a mud-making machine to obtain mud with good plasticity and uniform moisture content; Molding and internal structure shaping: The clay is filled into a special molding mold and pressed. The side wall 2 mold core has a raised structure, which can directly press out the preset hollow cavity, i.e. the flow channel 21, in the side wall 2 of the sagger. The bottom wall 1 mold core surface has a regular honeycomb array, which can directly form a honeycomb array texture structure on the inner surface of the bottom wall 1 of the sagger during pressing. Ventilation openings: On the side wall 2 of the green clay in the sagger, use special tools to precisely drill or punch out the planned ventilation openings, and set ventilation windows accordingly; Preparation of breathable powder barrier layer 4: A special slurry composed of nano alumina powder, pore-forming agent and sintering aid is prepared, and the special slurry is precisely coated onto the second ventilation window 32; Preliminary curing: Preliminary treatment is carried out at low temperature (e.g., 80-120℃) to shape the breathable powder barrier layer 4 and obtain preliminary strength in order to carry out subsequent drying; Drying: The treated sagger blanks are placed in a drying chamber at 120-150℃ and dried for 8-12 hours to completely remove moisture; Firing: The dried saggers are placed into a firing kiln for firing. The firing temperature is 1280-1400℃, and the temperature is held for 4-6 hours; Apply a high-temperature non-stick coating: After the sagger has cooled down after firing, a high-temperature non-stick coating is uniformly applied to the inner surface of the cavity using an atmospheric plasma spraying process.

[0045] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A sagger, characterized in that, include: bottom wall(1); Multiple sidewalls (2), the bottom ends of the multiple sidewalls (2) are respectively connected to the side of the bottom wall (1), the bottom wall (1) and the multiple sidewalls (2) together form a cavity for holding powder, and a flow channel (21) is provided in the sidewall (2), and the flow channel (21) in two adjacent sidewalls (2) are interconnected; Ventilation assembly, the ventilation assembly includes: ventilation port, a first ventilation port is provided on the outer wall of the side wall (2), a second ventilation port is provided on the inner wall of the side wall (2), and the first ventilation port and the second ventilation port are connected to the flow duct (21).

2. The sagger according to claim 1, characterized in that, Both the first vent and the second vent are equipped with vent windows, or only the second vent is equipped with the vent window.

3. The sagger according to claim 2, characterized in that, The first ventilation window (31) and the second ventilation window (32) are positioned opposite each other.

4. The sagger according to claim 3, characterized in that, The second ventilation window (32) is provided with a breathable powder-blocking layer (4) on the side away from the receiving cavity. The breathable powder-blocking layer (4) is adapted to block the powder in the receiving cavity from entering the flow channel (21).

5. The sagger according to claim 4, characterized in that, The average pore size of the breathable powder barrier layer (4) is smaller than the average particle size of the powder, and the average pore size is less than or equal to 1 μm.

6. The sagger according to claim 5, characterized in that, The air-permeable barrier layer (4) is sintered from one or more of porous alumina, porous magnesium oxide, porous spinel and porous zircon.

7. The sagger according to claim 1, characterized in that, The top surface of the bottom wall (1) is provided with a honeycomb array texture structure.

8. The sagger according to claim 7, characterized in that, The inner wall of the cavity is coated with a high-temperature anti-stick coating.

9. The sagger according to claim 1, characterized in that, The top of the sidewall (2) is provided with a groove (6).

10. The sagger according to any one of claims 1-9, characterized in that, The base material of the bottom wall (1) and the side wall (2) includes one or more of mullite, cordierite and mollite, and the bottom wall (1) and the side wall (2) are integrally formed by ceramic sintering process.

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