Coating and feeding system based on lithium battery silicon-based negative electrode slurry and control method of coating and feeding system

Abstract

The invention discloses a coating and feeding system based on lithium battery silicon-based negative electrode slurry and a control method of the coating and feeding system in the technical field of lithium battery manufacturing, and aims to solve the problems of coating foil leakage and low yield caused by the fact that an existing coating and feeding system cannot effectively process gas generated by the silicon-based negative electrode slurry. The system comprises a slurry mixing transfer tank, an electric ball valve, a first buffer tank, a defoaming unit, a first three-way valve, a second buffer tank, a second three-way valve, a die head, a self-circulation pipeline and an outer circulation pipeline, the defoaming unit comprises a continuous defoaming machine, a vacuum pump, a vacuum tank and a cooling device; the second buffer tank is provided with an anti-splashing device; the first three-way valve and the second three-way valve are used for switching the flow direction of The coating device is suitable for coating production of the silicon-based negative pole piece of the lithium battery, slurry bubbles can be efficiently eliminated, bubble regeneration is prevented, the feeding pressure is stabilized, and therefore the coating yield and the production efficiency are improved.

Description

Technical Field

[0001] This invention belongs to the field of battery manufacturing technology, specifically relating to a coating and feeding system and control method based on lithium battery silicon-based anode slurry. Background Technology

[0002] The energy density of silicon-based anode materials for lithium-ion batteries is more than ten times that of traditional graphite anode slurries. However, in this type of material, lithium ions undergo volume expansion and shedding during the migration and insertion process from the positive to the negative electrode, affecting battery cycle performance and safety. To address these issues, lithium-ion batteries are typically treated with carbon coating to improve material performance.

[0003] Typically, the anode material undergoes three processes: slurry preparation, coating, and roll forming to form a usable electrode sheet. However, the carbon-coated silicon-based anode material, after undergoing high-speed, high-pressure shearing in the slurry preparation process using a twin-screw or planetary mill, causes the carbon coating layer to detach. This continuously detached silicon then comes into constant contact with moisture or air, generating bubbles. During the coating process, the presence of these bubbles further leads to continuous and irregular foil leakage, resulting in extremely low yield.

[0004] Chinese patent CN221098324U discloses a coating feeding system, in which a pulse damper can eliminate pulse vibration in the pipeline, and a defoaming unit can eliminate foam in the pipeline, making the flow meter measurement results more accurate, thereby improving the control accuracy of the coating feeding system. However, the application effect of the defoaming unit is limited. After high-speed shearing, the coating layer of carbon-coated silicon-based material is damaged, and the gas generation phenomenon is more serious, which cannot meet the requirements of continuous and stable coating.

[0005] To address the aforementioned issues, there is an urgent need for a coating and feeding system and its control method based on silicon-based anode slurry for lithium batteries. This system would solve the coating leakage problem caused by gas generation in the silicon-based anode slurry, thereby overcoming production capacity bottlenecks and improving yield. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a coating feeding system and control method based on silicon-based anode slurry for lithium batteries, which can solve the coating foil leakage phenomenon caused by gas generation of silicon-based anode slurry, solve the production capacity bottleneck, and improve the yield.

[0007] To achieve the above objectives, the present invention is implemented using the following technical solution: In a first aspect, the present invention provides a coating and feeding system based on lithium battery silicon-based anode slurry, comprising a slurry transfer tank, a first buffer tank, a defoaming unit, a first three-way valve, a second buffer tank, a second three-way valve, and a die head, which are connected sequentially through a main feeding pipeline. The first buffer tank is connected to the first three-way valve via a self-circulation pipeline; the first buffer tank is connected to the second three-way valve via an external circulation pipeline; The first three-way valve is used to switch the slurry from the defoaming unit to the second buffer tank or to return it to the first buffer tank via the self-circulation pipeline; The second three-way valve is used to switch the slurry from the second buffer tank to the die head or to return it to the first buffer tank via the external circulation pipeline; The die head is used to spray material outwards.

[0008] The above setup achieves the following effects: By setting up a two-stage buffer consisting of a first buffer tank and a second buffer tank, and by using a first three-way valve and a second three-way valve in conjunction with a self-circulation pipeline and an external circulation pipeline, the present invention enables the system to switch under different working conditions, always maintaining the circulation of slurry, avoiding sedimentation, and ensuring that the slurry state and system pressure are sufficiently stabilized before entering the die head, thus guaranteeing coating uniformity.

[0009] Furthermore, the first buffer tank is provided with a main inlet, a main outlet, a self-circulating return outlet, and an external circulating return outlet; Both the first three-way valve and the second three-way valve are provided with an inlet, an outlet 1, and an outlet 2; The discharge port of the mixing transfer tank is connected to the main inlet of the first buffer tank; The main outlet of the first buffer tank is connected to the inlet of the defoaming unit; the self-circulation return port of the first buffer tank is connected to the outlet of the first three-way valve through a self-circulation pipeline; the external circulation return port of the first buffer tank is connected to the outlet of the second three-way valve through an external circulation pipeline. The outlet of the defoaming unit is connected to the inlet of the first three-way valve; the second outlet of the first three-way valve is connected to the inlet of the second buffer tank; the outlet of the second buffer tank is connected to the inlet of the second three-way valve; and the second outlet of the second three-way valve is connected to the die head.

[0010] The above settings achieve the following effects: By setting specific material inlets for the first and second buffer tanks and utilizing the valve settings of the first and second three-way valves, along with the interconnection between the self-circulation pipeline and the external circulation pipeline, the present invention maintains constant slurry circulation, avoids sedimentation, and ensures that the slurry state and system pressure are sufficiently stabilized before entering the die head, thus guaranteeing coating uniformity.

[0011] Furthermore, the die head is provided with a spray nozzle and an overflow port connected to the external circulation pipeline; the spray nozzle is used to spray material outward.

[0012] The above settings achieve the following effect: the overflow port of the die head is connected to the external circulation pipeline, forming an automatic pressure regulation mechanism, which further stabilizes the coating chamber pressure.

[0013] Furthermore, the defoaming unit includes a continuous defoaming machine, a vacuum pump, and a vacuum tank; The inlet of the continuous defoamer is connected to the main outlet of the first buffer tank, and the outlet is connected to the inlet of the second buffer tank. The vacuum pump is connected to the vacuum chamber of the continuous defoaming machine via the vacuum tank.

[0014] The above setup achieves the following effect: By processing the slurry online with a defoaming unit that includes a continuous defoamer, a vacuum pump, and a vacuum tank, bubbles in the silicon-based anode slurry can be efficiently and continuously eliminated, thus eliminating the main source of air that causes foil coating leakage. By setting up a vacuum tank between the vacuum pump and the continuous defoamer, the gas can be buffered, the pressure of the vacuum system can be stabilized, and the instantaneous fluctuations in the vacuum level can be effectively absorbed and reduced, ensuring the continuous high stability of the working vacuum environment inside the continuous defoamer, thereby ensuring the continuous and consistent defoaming effect.

[0015] Further configuration: The defoaming unit also includes a cooling device; the cooling device is used to cool the continuous defoaming machine and its output slurry.

[0016] The above setup achieves the following effect: the cooling device can quickly and accurately control the slurry temperature within the narrow range required by the process, avoiding changes in slurry viscosity caused by temperature fluctuations, thereby preventing unstable coating chamber pressure and surface density fluctuations caused by viscosity changes.

[0017] Further configuration: The cooling device includes a chiller and a cooling water pipeline, wherein the cooling water pipeline forms a jacket structure that surrounds the main feed pipeline between the outlet of the continuous defoamer and the first three-way valve; The end of the cooling water pipe is connected to the drive unit of the continuous defoamer.

[0018] The above setup achieves the following effect: by indirectly cooling the defoamed and heated slurry through the cooling water pipeline of the jacket structure, the slurry temperature can be quickly and accurately controlled within the narrow range required by the process, avoiding changes in slurry viscosity caused by temperature fluctuations, thereby preventing unstable coating chamber pressure and areal density fluctuations caused by viscosity changes.

[0019] By making full use of the residual cooling water to dissipate heat from the drive unit of the continuous defoamer, the equipment is protected from overheating due to long-term high-speed operation, and the heat source is avoided from reheating the slurry. This also achieves the cascade utilization of energy and reduces the overall energy consumption of the system.

[0020] Further feature: The second buffer container is equipped with a splash-proof device.

[0021] The above setup achieves the following effect: by installing an anti-splash device in the second buffer tank, the impact of the slurry entering the tank after defoaming is effectively buffered, preventing the generation of new bubbles and achieving full-process control of bubbles.

[0022] Further configuration: The anti-splash device includes a baffle plate arranged around the inside of the feed inlet of the second buffer tank; the highest point of the baffle plate is higher than the feed inlet of the second buffer tank.

[0023] The above setup achieves the following effect: using an inclined baffle as an anti-splash device is simple and reliable in structure, and can effectively decompose the impact force of vertical or oblique slurry, guiding the slurry to flow smoothly down the surface of the baffle, avoiding direct impact on the liquid surface.

[0024] Furthermore, the system also includes a host computer; An electric ball valve is installed between the slurry transfer tank and the first buffer tank to control the slurry output from the slurry transfer tank; The first buffer tank is equipped with a first liquid level sensor for acquiring the liquid level signal inside the first buffer tank; The second buffer tank is equipped with a second liquid level sensor for acquiring the liquid level signal inside the second buffer tank; The host computer is connected to the electric ball valve, the first liquid level sensor, the second liquid level sensor, the first three-way valve, and the second three-way valve, respectively, and is used to control the liquid circuit switching and on / off of the electric ball valve, the first three-way valve, and the second three-way valve according to the liquid level signals in the first buffer tank and the second buffer tank.

[0025] The above settings achieve the following effects: The second liquid level sensor is located above the upper panel of the buffer tank cover and is mainly used to detect the liquid level. At the same time, it communicates with the host computer and the defoamer to control the slurry level in the second buffer tank, keeping the slurry level in the second buffer tank within a 20% liquid level difference range. This effectively prevents large fluctuations in the cavity pressure inside the die head 8 due to large liquid level differences during the replenishment and consumption of slurry.

[0026] During the continuous supply of slurry, when the second liquid level sensor detects that the upper limit of the liquid level is higher than the threshold, the host computer outputs a command to the defoamer to stop supplying slurry. When the second liquid level sensor detects that the upper limit of the liquid level is lower than the threshold, it outputs a command to the defoamer to start supplying slurry.

[0027] Further configuration: The first buffer tank is equipped with a first stirring device and a first float device; The second buffer tank is equipped with a second stirring device and a second float device; Both the first and second stirring devices are used to stir the slurry inside the tank. The first and second float devices are used to prevent slurry from overflowing.

[0028] The above setup achieves the following effect: the first float device and the second float device are mainly used for mechanical error prevention to prevent slurry overflow after the first liquid level sensor fails to communicate.

[0029] The second stirring device has the same location and function as the first stirring device. It is mainly used to stir the slurry in the second buffer tank to prevent the slurry in the second buffer tank from settling.

[0030] Further configuration: The first buffer tank and the second buffer tank are respectively equipped with a first stirring device and a second stirring device.

[0031] The above setup achieves the following effect: by installing stirring devices in the first and second buffer tanks, the slurry inside the tanks can be continuously agitated, effectively preventing the sedimentation and agglomeration of solid particles (such as silicon-based active materials and conductive agents), ensuring that the composition and viscosity of the slurry supplied to the die head remain highly uniform, and laying the foundation for obtaining a consistent coating surface density.

[0032] Further configuration: The first buffer tank and the second buffer tank are respectively equipped with a first liquid level sensor and a second liquid level sensor.

[0033] The above setup achieves the following effects: By setting up level sensors and linking them with the host computer, automatic and precise control of the liquid levels in the first and second buffer tanks is realized. The first level sensor controls the start and stop of the material supply in the mixing transfer tank, ensuring safe material supply; the second level sensor controls the start and stop of the defoaming unit or the switching of the first three-way valve, stabilizing the liquid level in the second buffer tank within a narrow range, thereby greatly reducing the discharge pressure fluctuations caused by liquid level changes and providing extremely stable supply pressure for the die head.

[0034] Further configuration: The main inlet, self-circulation return inlet, and external circulation return inlet of the first buffer tank are all located on the upper part of the side wall of the tank and are higher than the rated liquid level.

[0035] The above setup achieves the following effects: placing all feed inlets on the upper part of the side wall and above the rated liquid level can prevent the slurry from directly impacting the settled material at the bottom of the tank (if any), reducing disturbance; at the same time, this high-level feeding method is conducive to the smooth mixing of slurry, reducing the introduction of air bubbles, and facilitating accurate monitoring and control of the liquid level inside the tank.

[0036] Further configuration: The outlet of the second buffer tank is connected in sequence to a screw pump, a scraper filter, a bladder filter, and a demagnetizing device via pipelines, and then connected to the inlet of the second three-way valve.

[0037] The above setup achieves the following effects: by providing stable conveying power through a screw pump, and through multi-stage treatment by a scraper filter, a capsule filter, and a demagnetizing device, it can effectively remove fine particles, gel clumps, and magnetic foreign objects generated in the slurry due to stirring, conveying, or equipment wear, greatly purifying the slurry, avoiding coating scratches or short circuit risks caused by foreign objects, and improving electrode quality and battery safety.

[0038] Based on the above coating supply system, the present invention provides a control method, including a coating start-up control process of the supply system, the process including the following steps: Start the defoaming unit to defoam the slurry drawn from the first buffer tank; The flow direction of the slurry is controlled by the first three-way valve, so that the deaerated slurry flows back to the first buffer tank for self-circulation of the deaerator; When the vacuum level inside the defoaming unit reaches the set value, the flow direction of the slurry is controlled by the first three-way valve, and the defoamed slurry is switched and transported to the second buffer tank. The flow direction of the slurry is controlled by the second three-way valve, so that the slurry flows out of the second buffer tank and then flows back to the first buffer tank to circulate the feeding system. Once the system pressure stabilizes, the slurry flow direction is controlled by the second three-way valve, switching the slurry to the die head for coating.

[0039] The above steps achieve the following effects: This coating start-up control method ensures that the slurry in the initial vacuum insufficient stage is recycled and reprocessed through "defoamer self-circulation," avoiding coating start-up defects; through "supply system circulation," the slurry is filled and flows through the entire system pipeline, fully purging pipeline gas, homogenizing the slurry, and stabilizing system pressure. This step-by-step process ensures that the slurry is completely defoamed and the system is in optimal working condition at the start of formal coating, thereby achieving a high yield of coating start-up and reducing material waste.

[0040] Further configuration: The control method also includes an abnormal control process for the material feeding system. When an abnormality occurs during coating, the following steps are executed: Control the die head to retract and seal its nozzle; The flow direction of the slurry is controlled by the second three-way valve, so that the slurry in the system can continuously flow back to the first buffer tank; After cleaning or washing the die head, resume coating.

[0041] The above setup achieves the following effects: This anomaly control process allows the die head to be isolated from the main feeding system when maintenance is required, while maintaining continuous slurry circulation within the main feeding system. This effectively prevents slurry settling, agglomeration, and the creation of new stability problems in pipelines and tanks caused by system downtime. It decouples local die head maintenance from global system operation, significantly reducing downtime and improving production continuity and equipment utilization.

[0042] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: This invention can clean the die head and solve the particle problem caused by deep settling inside the die head. On the other hand, while cleaning, the entire feeding system is still in a flowing state, which avoids the agglomeration and settling of slurry in the entire feeding system pipeline and further particle generation. Attached Figure Description

[0043] Figure 1 A schematic diagram of a silicon-based anode slurry feeding system; Figure 2 This is a schematic diagram of the first buffer tank; Figure 3 This is a schematic diagram of the second buffer tank; Figure 4 This is a schematic diagram of the die head's material output and return. Figure 5 Flowchart of the coating control method for the material supply system; Figure 6 This is a flowchart of the abnormal control method for the material feeding system.

[0044] In the diagram: 1. Mixing transfer tank; 2. Electric ball valve; 3. First buffer tank; 4. Defoaming unit; 5. First three-way valve; 6. Second buffer tank; 7. Second three-way valve; 8. Die head; 9. Main feed pipeline; 10. Self-circulation pipeline; 11. External circulation pipeline; 31. First liquid level sensor; 32. First float device; 33. First stirring device; 34. Main feed inlet; 35. Main discharge outlet; 36. Self-circulating return outlet; 37. External circulation return outlet; 38. First buffer tank cover; 41. Continuous defoaming machine; 42. Vacuum pump; 43. Vacuum tank; 44. Chiller; 45. Cooling water piping; 61. Second liquid level sensor; 62. Second float device; 63. Second stirring device; 64. Inlet; 65. Outlet; 66. Second buffer tank cover; 67. Anti-splash device; 81. Spray nozzle; 82. Overflow port. Detailed Implementation

[0045] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0046] In the description of this embodiment, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this embodiment and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this embodiment. Example 1

[0047] This embodiment provides a coating and feeding system based on lithium battery silicon-based anode slurry, including a slurry transfer tank 1, a first buffer tank 3, a defoaming unit 4, a second buffer tank 6, a first three-way valve 5, a second three-way valve 7, and a die head 8; The first buffer tank 3 is provided with a main inlet 34, a main outlet 35, a self-circulating return outlet 36 and an external circulation return outlet 37; The first three-way valve 5 and the second three-way valve 7 are both provided with an inlet, an outlet 1, and an outlet 2; The discharge port of the mixing transfer tank 1 is connected to the main inlet 34 of the first buffer tank 3 through the main feed pipeline 9; The main discharge port 35 of the first buffer tank 3 is connected to the inlet of the defoaming unit 4; the self-circulation return port 36 of the first buffer tank 3 is connected to the discharge port 1 of the first three-way valve 5 through the self-circulation pipeline 10; the external circulation return port 37 of the first buffer tank 3 is connected to the discharge port 1 of the second three-way valve 7 through the external circulation pipeline 11. The outlet of the defoaming unit 4 is connected to the inlet of the first three-way valve 5; the second outlet of the first three-way valve 5 is connected to the inlet 64 of the second buffer tank 6; the outlet 65 of the second buffer tank 6 is connected to the inlet of the second three-way valve 7; and the second outlet of the second three-way valve 7 is connected to the die head 8. The first three-way valve 5 is used to switch the slurry from the defoaming unit 4 to the second buffer tank 6 or to return it to the first buffer tank 3 via the self-circulation pipeline 10; The second three-way valve 7 is used to switch the slurry from the second buffer tank 6 to the die head 8 or to return it to the first buffer tank 3 via the external circulation pipeline 11; The die head 8 is used to spray material outwards.

[0048] Implementation principle: This invention sets up a two-stage buffer consisting of a first buffer tank 3 and a second buffer tank 6, and uses a first three-way valve 5 and a second three-way valve 7 in conjunction with a self-circulation pipeline 10 and an external circulation pipeline 11 to enable the system to switch under different working conditions, always maintain the circulation of slurry, avoid sedimentation, and ensure that the slurry state and system pressure are fully stabilized before entering the die head 8, thus ensuring coating uniformity. Example 2

[0049] This embodiment provides a coating and feeding system based on lithium battery silicon-based anode slurry, including a slurry transfer tank 1, an electric ball valve 2, a first buffer tank 3, a defoaming unit 4, a first three-way valve 5, a second buffer tank 6, a second three-way valve 7, a die head 8, a main feeding pipeline 9, a self-circulation pipeline 10, and an external circulation pipeline 11.

[0050] The mixing transfer tank 1, electric ball valve 2, first buffer tank 3, defoaming unit 4, first three-way valve 5, second buffer tank 6, second three-way valve 7, and die head 8 are connected in sequence through the main feeding pipeline 9.

[0051] The mixing and transfer tank 1 is mainly used to buffer the silicon-based negative electrode slurry after the pulping is completed and to provide the required slurry for the entire coating feeding system.

[0052] The electric ball valve 2 is mainly used to control the start and stop of the material supply to the mixing transfer tank 1.

[0053] The first buffer tank 3 includes a first liquid level sensor 31, a first float device 32, a first stirring device 33, a main feed port 34, a main discharge port 35, a self-circulating return port 36, an external circulation return port 37, and a first buffer tank cover plate 38.

[0054] The first liquid level sensor 31 is located above the upper panel of the first buffer tank cover 38. It includes, but is not limited to, an infrared liquid level sensor or an ultrasonic liquid level sensor. It is mainly used to detect the liquid level. At the same time, through communication with the host computer and the electric ball valve 2, it controls the slurry level of the first buffer tank 3 to ensure the safety of slurry supply.

[0055] For example, if the upper limit of the liquid level in the first buffer tank 3 is set to 80% and the lower limit to 20% by the host computer, then when the slurry is continuously supplied, if the first liquid level sensor 31 detects that the upper limit of the liquid level has reached 80%, it will send a signal to the host computer. The host computer will then output a command to the electric ball valve 2 to close the valve, and the slurry transfer tank 1 will stop supplying material to the first buffer tank 3 to prevent the supply flow of the slurry transfer tank 1 from exceeding the consumption of the defoaming unit 4, which would lead to slurry overflow. If the first liquid level sensor 31 detects that the upper limit of the liquid level is lower than 20%, it will send a signal to the host computer, and the host computer will output a command to the electric ball valve 2 to open the valve, and the slurry transfer tank 1 will continue to supply material to the first buffer tank 3 to prevent insufficient slurry in the first buffer tank 3.

[0056] The first float device 32 is mainly used for mechanical error prevention to prevent slurry overflow after the first liquid level sensor 31 fails to communicate.

[0057] The first stirring device 33 is mainly used to stir the slurry, so that the slurry in the first buffer tank 3 is in a continuous flow state, avoiding the sedimentation of the slurry.

[0058] The main feed inlet 34, the self-circulating return inlet 36, and the external circulation return inlet 37 are all located on the side of the first buffer tank 3 and are higher than the rated liquid level of the first buffer tank 3. The rated liquid level refers to the liquid level of 100% of the theoretical usable volume of the tank, not the maximum usable volume.

[0059] Main feed inlet 34 is mainly used to receive slurry from mixing transfer tank 1. The self-circulating return port 36 is mainly used to receive slurry that flows into the first buffer tank 3 tangentially from the first three-way valve 5.

[0060] The external circulation return port 37 is mainly used to receive the slurry that has been circulated back to the first buffer tank 3 through the second three-way valve 7.

[0061] The main discharge port 35 is located at the bottom of the first buffer tank 3 and serves as the slurry output port of the first buffer tank 3, outputting to the defoaming unit 4.

[0062] The defoaming unit 4 includes a continuous defoamer 41, a vacuum pump 42, a vacuum tank 43, a chiller 44, and a cooling water pipeline 45.

[0063] The defoamer 41 is an online continuous defoaming device based on the VTR (Vacuum Thin Film Rotation Principle). It removes air bubbles from the material by rotating the slurry at high speed in a vacuum environment. The slurry processed by the defoamer 41 is discharged in a continuous clump form.

[0064] The vacuum pump 42 is mainly used to draw a vacuum inside the defoamer 41, and at the same time, it draws the slurry in the first buffer tank 3 into the defoamer 41 for defoaming.

[0065] The vacuum tank 43 is mainly used to buffer and stabilize the air pressure between the defoamer 41 and the vacuum pump, so that the vacuum inside the defoamer 41 is more stable during operation.

[0066] The defoamer 41 uses a combination of vacuum pump 42 and vacuum tank 43 to achieve a vacuum level of -0.09MPA or higher. Combined with the film rotation principle of the defoamer 41, the air bubbles in the slurry can be quickly and effectively eliminated and the slurry can be continuously output.

[0067] The chiller 44 is mainly used to provide cooling water to the cooling water pipes 45.

[0068] The cooling water pipe 45, on the one hand, wraps around the main pipe 9 between the defoamer 41 and the first three-way valve 5 in the form of a jacketed pipe, cooling the heated slurry after it has been treated by the defoamer 41, so that the temperature of the defoamed slurry is maintained within 23±2℃, effectively preventing changes in slurry viscosity during subsequent pipeline transmission. On the other hand, the water outlet of the jacketed pipe is connected to the drive device of the defoamer 41 for cooling, effectively preventing the overall equipment temperature rise caused by the high-speed rotation of the drive device of the defoamer 41, which would affect the viscosity of the slurry. This also prevents large fluctuations in cavity pressure in the coating die head 8 due to viscosity fluctuations, which would cause instability in dimensions and areal density during the coating process.

[0069] The cooling water in the chiller 44 first cools the slurry in the main pipeline 9 between the defoamer 41 and the first three-way valve 5, then makes full use of the remaining cooling water energy to cool the defoamer 41, and finally flows back to the chiller for processing, which greatly reduces the energy loss of the chiller.

[0070] The first three-way valve 5 is mainly used to switch the flow direction of the slurry after it has been cooled by the chiller 44. It determines whether the slurry flows into the second buffer tank 6 through the main pipeline 9 or into the first buffer tank 3 through the self-circulation pipeline 10 and the self-circulation return port 36.

[0071] During the initial startup phase, the vacuum level inside the defoaming unit 4 takes a short time to reach the specified pressure, which can result in poor defoaming of the slurry output from the defoaming machine 41. Therefore, the slurry flow can be switched to the self-circulation pipeline 10 through the first three-way valve 5, and then flow into the first buffer tank 3 through the self-circulation return port 36. The slurry with poor initial defoaming effect flows into the first buffer tank 3 to form a circulation process, avoiding waste of the initial slurry. After the vacuum level inside the defoaming unit 4 reaches the specified requirements, the slurry flow can be switched to the second buffer tank 6 through the first three-way valve 5, effectively avoiding the phenomenon of coating bubbles and foil leakage caused by incomplete defoaming of the initial material.

[0072] The second buffer tank 6 includes a second level sensor 61, a second float device 62, a second stirring device 63, a feed inlet 64, a discharge outlet 65, a second buffer tank cover 66, and an anti-splash device 67. The second buffer tank 6 is mainly used to collect and buffer the slurry output from the deaerator 41 through the main pipeline 9 and the feed inlet 64. The slurry is mainly pumped out from the discharge outlet 65 by a screw pump. After being processed by a scraper filter, a slurry filter, and a demagnetizing device, the pumped slurry is switched to feed to the die head 8 through the second three-way valve 7.

[0073] The difference between the first buffer tank 3 and the second buffer tank 6 lies in two aspects. Firstly, the first buffer tank 3 serves as the final circulation container for the slurry in the entire feeding system. All circulating slurry ultimately flows into the first buffer tank 3 through the self-circulation return port 36 and the external circulation return port 37 for buffering. After being processed by the defoaming unit 4, the slurry flows to the die head 8, ensuring that no bubbles are generated during the entire feeding process. Secondly, the liquid level control methods of the first buffer tank 3 and the second buffer tank 6 differ. The second buffer tank 6 has a lower range for the upper and lower liquid level limits, which is used to ensure stable feeding to the final die head 8. The second liquid level sensor 61 is located above the upper panel of the buffer tank cover 66. It includes, but is not limited to, an infrared liquid level sensor or an ultrasonic liquid level sensor. It is mainly used to detect the liquid level. At the same time, it communicates with the host computer and the defoamer 41 to control the slurry level in the second buffer tank 6, keeping the slurry level in the second buffer tank 6 within a 20% liquid level difference range. This can effectively prevent large fluctuations in the cavity pressure in the die head 8 due to large liquid level differences during the replenishment and consumption of slurry.

[0074] For example, if the upper limit of the liquid level of the second buffer tank 6 is set to 80% and the lower limit of the liquid level is set to 60% by the host computer, then when the slurry is continuously supplied, when the second liquid level sensor 61 detects that the upper limit of the liquid level reaches 80%, it outputs a command to the defoamer 41 to stop the supply of slurry. When the second liquid level sensor 61 detects that the upper limit of the liquid level is lower than 60%, it outputs a command to the defoamer 41 to start the supply of slurry.

[0075] The second float device 62 is mainly used for mechanical error prevention to prevent slurry overflow after the communication of the first liquid level sensor 61 fails.

[0076] The second stirring device 63 has the same position and function as the first stirring device. It is mainly used to stir the slurry in the second buffer tank 6 to prevent the slurry in the second buffer tank 6 from settling.

[0077] The inlet 64 is located on the side wall of the second buffer tank 6 and is 100% above the rated liquid level of the second buffer tank 6. It is mainly used for inputting slurry. The outlet 65 is located at the bottom center of the second buffer tank 6. It is mainly used for outputting slurry.

[0078] The anti-splash device 67 is located on the inner wall of the second buffer tank 6 and is set near the feed inlet 64. It can effectively buffer the slurry sprayed from the feed inlet 64 from directly contacting the liquid surface in the second buffer tank 6, generating air bubbles, which would cause foil leakage during subsequent coating of the die head 8.

[0079] For example, when the defoamer 41 is working continuously, it will output in the form of continuously spraying clumps of slurry. At this time, the sprayed slurry will have a certain impact force. After entering through the feed port 64, it will splash bubbles after directly contacting the liquid surface of the second buffer tank 6. The baffle of the anti-splash device 67 can effectively buffer the impact force of the slurry, and further allow the buffered slurry to flow into the second buffer tank 6 along the wall, effectively preventing bubbles generated by slurry collision.

[0080] The second three-way valve 7 is mainly used to switch the flow direction of slurry in the second buffer tank 6. It flows into the die head 8 continuously through the main feed pipeline 9, or into the first buffer tank 3 through the external circulation pipeline 11.

[0081] The die head 8 includes a spray nozzle 81 and an overflow nozzle 82. The spray nozzle 81 is mainly used to spray slurry onto the foil to form an electrode in a wet film state. The overflow nozzle 82 is mainly used to allow excess slurry in the cavity of the die head 8 to flow into the first buffer tank 3. When the cavity pressure is too high, the slurry can overflow through the overflow nozzle 82 and flow into the external circulation pipe 11, and then flow into the second buffer tank 6 through the external circulation pipe 11.

[0082] Specifically, this system includes the following components: The slurry transfer tank 1 is typically a tank-shaped container used to store slurry. Its outlet 65 is connected to the inlet of the electric ball valve 2 via a pipeline. It is mainly used to buffer the silicon-based negative electrode slurry completed in the slurry preparation process, serving as the initial slurry source for the entire coating supply system.

[0083] Electric ball valve 2, a ball valve driven by an electric actuator, is used for controlling the on / off flow of media in a pipeline. Its inlet end is connected to the outlet 65 of the mixing and transfer tank 1 via a pipeline, and its outlet end is connected to the main inlet 34 of the first buffer tank 3 via a pipeline. Its control signal terminal is connected to a host computer, mainly used to receive commands from the host computer to control the start and stop of material supply from the mixing and transfer tank 1 to the first buffer tank 3, thereby achieving automatic liquid level control.

[0084] The first buffer tank 3 is a vertical tank with a first buffer tank cover 38 on top. The tank is connected to the system through multiple interfaces: the main inlet 34 is connected to the outlet of the electric ball valve 2; the main outlet 35 is connected to the inlet of the defoaming unit 4; the self-circulation return port 36 is connected to one outlet of the first three-way valve 5 through the self-circulation pipeline 10; and the external circulation return port 37 is connected to one outlet of the second three-way valve 7 through the external circulation pipeline 11. The tank is equipped with a first stirring device 33, and the tank cover is equipped with a first liquid level sensor 31 and a first float device 32. It is mainly used to receive and buffer new slurry from the mixing transfer tank 1, as well as return slurry from the self-circulation and external circulation. Stirring prevents slurry sedimentation, and the liquid level sensor, in conjunction with the host computer and the electric ball valve 2, controls the slurry level in the tank. It is the core buffer unit for slurry collection and reprocessing in the entire feeding system.

[0085] The first liquid level sensor 31, which can be an infrared or ultrasonic sensor probe, is installed on the cover plate 38 of the first buffer tank, with its detection probe extending into the tank. Its signal output terminal is connected to a host computer, primarily used for real-time detection of the slurry level in the first buffer tank 3 and transmitting the signal to the host computer for automatic liquid level control.

[0086] The first float device 32, a mechanical float level switch, is installed on the cover plate 38 of the first buffer tank. It is mainly used as a redundant safety device for the level sensor. When the first level sensor 31 fails, it is triggered mechanically when the level is too high to prevent slurry from overflowing.

[0087] The first stirring device 33 is a stirrer driven by a motor, including a motor, a shaft and a blade. The motor part is fixed to the cover plate 38 of the first buffer tank. The stirring shaft and the blade extend into the slurry in the tank. It is mainly used to continuously stir the slurry in the first buffer tank 3 to keep it in a uniform flow state and prevent solid particles from settling.

[0088] The main feed inlet 34 is a tubular interface located on the upper side wall of the first buffer tank 3. It is connected to the outlet of the electric ball valve 2 via a pipeline and is mainly used to receive fresh pulp from the mixing transfer tank 1.

[0089] The main discharge port 35 is a tubular interface located at the bottom of the first buffer tank 3. It is connected to the inlet of the continuous defoamer 41 in the defoaming unit 4 via a pipeline. It is mainly used as the output port of the slurry in the first buffer tank 3 to supply the slurry to the defoaming unit 4.

[0090] The self-circulating return port 36 is a tubular interface located on the upper side wall of the first buffer tank 3. It is connected to one outlet of the first three-way valve 5 through the self-circulating pipeline 10. It is mainly used to receive the slurry that is in the "deaerator self-circulation" state after switching back from the first three-way valve 5.

[0091] The external circulation return port 37 is a tubular interface located on the upper side wall of the first buffer tank 3. It is connected to one outlet of the second three-way valve 7 through the external circulation pipeline 11. It is mainly used to receive slurry that is in the "supply system circulation" state after switching back from the second three-way valve 7, or slurry that flows back from the overflow port 82 of the die head 8.

[0092] The first buffer tank cover plate 38 is a plate-shaped sealing structure covering the top of the first buffer tank 3. It is fixedly installed on the top of the tank body of the first buffer tank 3. The first liquid level sensor 31, the first float device 32 and the motor part of the first stirring device 33 are installed on it. It is mainly used to seal the tank body and provide a mounting base for related detection and execution components.

[0093] The defoaming unit 4 is a unit composed of multiple sub-equipment. As a functional unit, its inlet is connected to the main outlet 35 of the first buffer tank 3, and its outlet is connected to the inlet of the first three-way valve 5 through the main feed pipeline 9. It is mainly used for online continuous degassing and cooling of the slurry and is the core functional module for eliminating air bubbles in the slurry.

[0094] The continuous defoamer 41 is a device based on the vacuum film rotation (VTR) principle. It has a high-speed rotating component inside, which is used to spread the slurry into a film. The material inlet is connected to the main outlet 35 of the first buffer tank 3; the material outlet is connected to the main feed pipeline 9; the vacuum port is connected to the vacuum tank 43 through the vacuum pipeline; the drive device can be cooled by connecting to a branch of the cooling water pipeline 45 through the pipeline. It is mainly used to spread the slurry into a film through high-speed rotation in a vacuum environment, so that the bubbles inside the slurry can be quickly escaped and removed, thereby achieving continuous and efficient defoaming.

[0095] Vacuum pump 42 is a pump used to remove gas. It is connected to vacuum tank 43 through vacuum pipeline. It is mainly used to provide a vacuum source for the entire defoaming unit 4, extract gas in continuous defoamer 41, and assist in drawing slurry from first buffer tank 3 into continuous defoamer 41.

[0096] Vacuum tank 43 is a tank-shaped container used to buffer gas. It is connected to the vacuum pipeline between vacuum pump 42 and vacuum port of continuous defoamer 41. It is mainly used to stabilize the vacuum level in the defoaming system, buffer vacuum fluctuations, and ensure the stability of the working vacuum inside continuous defoamer 41.

[0097] Chiller 44 is a device that provides circulating cooling water. It provides cooling water to the system through cooling water pipe 45 and is mainly used to provide a constant temperature cooling water source for cooling water pipe 45.

[0098] The cooling water pipeline 45 includes a main pipeline and possible branch pipelines. The main pipeline section is a jacketed pipe structure, that is, the inner pipe carries the slurry, and the outer jacket carries cooling water, with the inlet connected to the outlet of the chiller 44; the jacket section is wrapped around the main feed pipeline 9 between the outlet of the continuous defoamer 41 and the first three-way valve 5; the outlet end can branch a line to the drive unit of the continuous defoamer 41; the final return water port is connected to the return water port of the chiller 44, mainly used to indirectly cool the slurry whose temperature rises after defoaming by using cooling water, thereby controlling the slurry temperature; at the same time, the residual cooling is used to cool the drive unit of the continuous defoamer 41.

[0099] The first three-way valve 5 is a pipeline switching valve with one inlet and two outlets, controlled electrically or pneumatically. The inlet is connected to the outlet of the defoaming unit 4 through the main feed pipeline 9; one outlet is connected to the inlet 64 of the second buffer tank 6 through the main feed pipeline 9; and the other outlet is connected to the self-circulation return port 36 of the first buffer tank 3 through the self-circulation pipeline 10. The control terminal is connected to the host computer and is mainly used to switch the flow direction of the defoamed slurry according to the instructions of the host computer: one is to flow to the second buffer tank 6 for subsequent feeding, and the other is to switch back to the first buffer tank 3 for "defoaming machine self-circulation".

[0100] The second buffer tank 6 is a vertical tank with a second buffer tank cover 66 on top and an anti-splash device 67 on the inner wall. The tank inlet 64 is connected to the corresponding outlet of the first three-way valve 5 through the main feed pipeline 9; the outlet 65 is connected to the inlet of the second three-way valve 7 through pipelines connected in sequence to a screw pump, a filter, etc. The tank is equipped with a second stirring device 63, and the tank cover is equipped with a second liquid level sensor 61 and a second float device 62. It is mainly used to buffer the qualified slurry after defoaming and cooling, serving as a buffer for direct feeding to the die head 8. Stirring prevents sedimentation, and liquid level control stabilizes the feeding pressure to the die head 8. The internal anti-splash device 67 is used to prevent the generation of new bubbles when the slurry enters the tank.

[0101] The second liquid level sensor 61, which can be an infrared or ultrasonic sensor probe, is installed on the cover plate 66 of the second buffer tank, with its detection probe extending into the tank. Its signal output terminal is connected to a host computer and is mainly used to detect the slurry level in the second buffer tank 6 in real time, transmitting the signal to the host computer to control the start / stop of the defoaming unit 4 or the switching of the first three-way valve 5, thereby maintaining the liquid level in the tank within a narrow range.

[0102] The second float device 62, a mechanical float level switch, is installed on the cover plate 66 of the second buffer tank. It is mainly used as a redundant safety device for the level sensor. When the second level sensor 61 fails, it is triggered mechanically when the level is too high to prevent slurry from overflowing.

[0103] The second stirring device 63 is a stirrer driven by an electric motor, including a motor, a shaft and blades. The motor part is fixed to the cover plate 66 of the second buffer tank. The stirring shaft and blades extend into the slurry in the tank and are mainly used to continuously stir the slurry in the second buffer tank 6 to prevent sedimentation.

[0104] The feed inlet 64 is a tubular interface located on the upper side wall of the second buffer tank 6. It is connected to the corresponding outlet of the first three-way valve 5 through the main feed pipeline 9. It is mainly used to receive the defoamed slurry from the defoaming unit 4 and switched through the first three-way valve 5.

[0105] The discharge port 65 is a tubular interface located at the center of the bottom of the second buffer tank 6. It is connected to the inlet of the screw pump through a pipeline. The pump outlet is then connected to the second three-way valve 7 through a scraper filter, a bladder filter, a demagnetizing device, etc. It is mainly used as the output port of the slurry in the second buffer tank 6, pumping out the slurry and supplying it to the subsequent pipeline after filtration and purification.

[0106] The second buffer tank cover plate 66 is a plate-shaped sealing structure covering the top of the second buffer tank 6. It is fixedly installed on the top of the tank body of the second buffer tank 6. The second liquid level sensor 61, the second float device 62, and the motor part of the second stirring device 63 are installed on it. It is mainly used to seal the tank body and provide a mounting base for related detection and execution components.

[0107] The anti-splash device 67 is a baffle fixed to the inner wall of the tank, usually in the shape of an arc or a slope. It is installed on the inner wall of the second buffer tank 6, positioned directly opposite and slightly lower than the feed inlet 64. Its lower edge leaves a gap with the tank wall. It is mainly used to buffer the impact force of the lumpy slurry entering at high speed from the feed inlet 64, guide the slurry to flow down smoothly along the wall, and prevent the slurry from directly impacting the liquid surface and generating new bubbles.

[0108] The second three-way valve 7 is a pipeline switching valve with one inlet and two outlets, electrically or pneumatically controlled. The inlet connects to the slurry pipeline from the outlet 65 of the second buffer tank 6, which has been pumped and filtered for purification. One outlet connects to the inlet 64 of the die head 8 via the main feed pipeline 9. The other outlet connects to the external circulation return port 37 of the first buffer tank 3 via the external circulation pipeline 11. The control terminal connects to the host computer and is mainly used to switch the final flow direction of the slurry according to the host computer's instructions: one is to supply the die head 8 for coating, and the other is to switch back to the first buffer tank 3 for "feeding system circulation" or to handle the overflow slurry from the die head 8.

[0109] The die head 8 is a key component of the coating machine. It has internal cavities and slits. Its inlet 64 is connected to the corresponding outlet of the second three-way valve 7 via the main feed pipeline 9. Its overflow port 82 is connected to the external circulation pipeline 11 via a pipeline. It is mainly used to uniformly coat the slurry onto the foil to form a wet film electrode. The internal cavity pressure must be kept stable to ensure coating quality.

[0110] The nozzle 81 and the slit-shaped outlet 65 at the front end of the die head 8 are part of the structure of the die head 8. They face the coating foil directly and are mainly used to spray the slurry onto the moving foil surface in a specific shape and width.

[0111] Overflow port 82 is a return port opened on the die head 8. It is connected to the external circulation pipe 11 through a pipeline. It is mainly used to discharge excess slurry from this port when the internal cavity pressure of the die head 8 is too high or when circulation is required, and return it to the first buffer tank 3 to stabilize the cavity pressure of the die head 8 and maintain the flow of slurry.

[0112] The main feed pipeline 9 is a network of pipelines connecting the main functional components. It is connected in series with the outlet of the mixing transfer tank 1, the electric ball valve 2, the main feed port 34 of the first buffer tank 3, the defoaming unit 4, the first three-way valve 5, the feed port 64 of the second buffer tank 6, the second three-way valve 7, and the feed port 64 of the die head 8. It is mainly used to form the main conveying channel for the slurry from mixing to coating.

[0113] The self-circulation pipeline 10 is a pipe connecting the first three-way valve 5 and the self-circulation return port 36 of the first buffer tank 3. It is connected between one outlet of the first three-way valve 5 and the self-circulation return port 36 of the first buffer tank 3. It is mainly used to form a "defoamer self-circulation" loop, which is used to return the defoamed slurry to the first buffer tank 3 when the system starts up or when the liquid level of the second buffer tank 6 is high.

[0114] The external circulation pipeline 11 is a pipe that connects the second three-way valve 7, the overflow port 82 of the die head 8, and the external circulation return port 37 of the first buffer tank 3. One end is connected to one outlet of the second three-way valve 7 and / or the overflow port 82 of the die head 8, and the other end is connected to the external circulation return port 37 of the first buffer tank 3. It is mainly used to form a "supply system circulation" loop. It is used to guide the slurry back to the first buffer tank 3 during the system pressure stabilization stage, abnormal handling, or when the die head 8 overflows, so as to maintain the circulation flow of slurry in the system.

[0115] Implementation principle: The core principle of this invention is to actively intervene in and manage the entire process of silicon-based anode paste from feeding to coating through an integrated hardware system and intelligent control logic, so as to achieve closed-loop control of "bubble elimination - bubble prevention and control - state stabilization", thereby eradicating the problem of foil leakage in coating.

[0116] 1. Principle of bubble elimination: Vacuum Thin Film Rotary Degassing: The core of the system is a continuous defoamer 41 based on the VTR (vacuum thin film rotation) principle. Its working principle is as follows: Under a stable high vacuum environment (e.g., below -0.095 MPa) established by the vacuum pump 42, the slurry is fed into the high-speed rotating rotor inside the defoamer, where it is spread into an extremely thin film by centrifugal force. Under vacuum conditions, the pressure difference between the inside and outside of the bubbles in the slurry increases sharply, causing the bubbles to expand and burst rapidly, and the gas is extracted by the vacuum system. Thin film formation greatly increases the surface area of ​​the slurry and shortens the escape path of the bubbles, thereby achieving efficient and continuous physical degassing and eliminating the main gas source causing foil leakage at its source.

[0117] 2. Principle of bubble control: Anti-splash design at the inlet: After defoaming, the slurry is sprayed out at high speed in a continuous "clump" form. If it directly impacts the liquid surface of the second buffer tank 6, new bubbles will be generated. This system is equipped with an anti-splash device 67 (such as an inclined baffle) below the inlet 64 of the second buffer tank 6. The principle is that the high-speed slurry flow first hits the surface of the baffle, and the kinetic energy is buffered and dispersed. Then the slurry flows smoothly down the inclined surface of the baffle and gently integrates into the slurry in the tank, avoiding liquid surface impact and fundamentally preventing the secondary generation of bubbles during the transportation process.

[0118] 3. Principle of State Stability: Two-stage buffering and pressure buffering: The system is equipped with a first buffer tank 3 and a second buffer tank 6. The first buffer tank 3 acts as a "distribution and buffer center," receiving new slurry and all return slurry. Its liquid level control range is relatively wide, ensuring safe material supply. The second buffer tank 6 acts as a "precision pressure stabilization buffer," with its liquid level controlled within a very narrow range (e.g., 60%-80%). The principle is that a stable liquid level means minimal change in the static pressure head at the outlet 65 (drawn by a screw pump), thus providing an extremely stable supply pressure base for the downstream die head 8. This is crucial for achieving uniform coating surface density.

[0119] Dual-loop circulation and temperature control: Circulating and Stabilizing Flow: Through the self-circulating pipeline 10 and the external circulation pipeline 11, in conjunction with two three-way valves, the system can keep the slurry flowing continuously in a closed loop under different operating conditions (such as startup, standby, and cleaning). The principle is to keep the slurry in motion at all times, prevent solid particles from settling and agglomerating, and at the same time allow the slurry sufficient path and time to homogenize its rheological properties, expel residual gas, and stabilize the overall system pressure before entering the die head 8.

[0120] Precise temperature control: The defoaming process generates heat, and increased slurry temperature leads to viscosity changes, affecting coating. The system uses a jacketed cooling water pipeline (45°) to enclose the defoamed slurry pipeline. Its principle is to utilize indirect heat exchange with cooling water to quickly and accurately control the slurry temperature within a set range (e.g., 25±2℃), eliminating the interference of temperature fluctuations on slurry viscosity and coating chamber pressure. Residual cooling is also used to cool the defoamer drive unit, achieving energy savings.

[0121] In summary, this invention transforms a silicon-based anode slurry that is prone to gas generation and unstable into a uniform, bubble-free, and constant-state "coatable slurry" through the synergistic effects of "online vacuum thin-film defoaming (actively eliminating bubbles) + anti-splash feeding (passively preventing bubbles) + dual-tank pressure stabilization and dual-path circulation (stabilizing slurry state and pressure) + precise cooling (stabilizing slurry viscosity)".

[0122] The system operation is mainly controlled by the host computer (PLC / DCS) program, and consists of the following main processes: (I) System startup and normal coating process 1. Preparation and Feeding: Start the system and the host computer detects the liquid level in the first buffer tank 3. If it is lower than the set lower limit (e.g., 20%), the electric ball valve 2 is opened, and the slurry in the mixing transfer tank 1 begins to be injected into the first buffer tank 3.

[0123] 2. Defoaming and self-circulation: Start the defoaming unit 4 (including chiller 44, vacuum pump 42, and continuous defoamer 41). Vacuum pump 42 starts to draw a vacuum, and the defoamer draws slurry from the bottom of the first buffer tank 3.

[0124] At this point, the first three-way valve 5 is switched to "self-circulation" mode. The defoamed slurry does not enter the second buffer tank 6, but returns directly to the first buffer tank 3 through the self-circulation pipeline 10. This step is called "defoamer self-circulation," and its purpose is to recycle the insufficiently defoamed slurry before the system vacuum degree reaches stability, avoiding waste and coating defects.

[0125] 3. Switch to feed buffer: Once the monitoring system displays that the vacuum level inside the defoamer has reached and stabilized at the set value (e.g., -0.095MPa), the host computer switches the first three-way valve 5 to the "feed" mode. The defoamed slurry then enters the second buffer tank 6 through the main feed pipeline 9.

[0126] 4. System pressure closed-loop stability: The host computer controls the second three-way valve 7 to switch to "circulation" mode and starts the screw pump that draws slurry from the second buffer tank 6.

[0127] After passing through a filter to remove particles and metal impurities, the slurry does not enter the die head 8, but is returned entirely to the first buffer tank 3 via the external circulation pipeline 11. This step is called "supply system circulation," and its purpose is to allow the slurry to circulate fully throughout the entire system pipeline, vent the pipeline gas, and bring the slurry flow pattern, temperature, and system pressure to a completely stable state.

[0128] 5. Begin coating: After the system pressure sensor signal stabilizes for a certain period of time, the host computer switches the second three-way valve 7 to the "coating" mode.

[0129] The slurry is supplied to the die head 8 and evenly coated onto the foil through the spray nozzle 81, and normal coating begins. The pressure inside the die head 8 is connected to the external circulation pipeline 11 through the overflow port 82, automatically releasing and stabilizing the pressure.

[0130] 6. Process maintenance: The second buffer tank 6 is controlled by a level sensor 61, which monitors the level in real time. When the level is above the upper limit (e.g., 80%), a signal is sent to the host computer, which can pause the defoamer's feeding or briefly switch back to self-circulation. When the level is below the lower limit (e.g., 60%), the signal triggers the defoamer to start or increase its feeding. This closed-loop control ensures a stable level in the second buffer tank 6, thereby guaranteeing a constant feeding pressure in the die head 8.

[0131] (II) Troubleshooting and Mold Head Cleaning Process 1. Anomaly detection and isolation: If anomalies such as frequent scraping or particle streaking are detected during the coating process.

[0132] 2. Mold head 8 exits and cycle continues: The host computer issues the "remove mold head 8" command, and the coating machine stops.

[0133] The nozzle 81 of the die head 8 is sealed manually with high-temperature tape.

[0134] The host computer ensures that the second three-way valve 7 is in "circulation" mode. At this time, the entire feeding system (including the cavity of the die head 8 through the overflow port 82) keeps the external circulation pipeline 11 unobstructed, and the slurry continuously circulates within the system.

[0135] 3. Online cleaning and deep cleaning: Online cleaning: With the system in continuous circulation, the operator can clean the lip of the nozzle 81. The circulating slurry carries away some particles from inside the die head 8, which are then captured and removed by the scraper filter and bladder filter in the pipeline.

[0136] Deep cleaning: If the problem is severe, the small branch valve connecting to the die head 8 can be closed while maintaining the main system circulation, and the die head 8 can be removed for offline deep cleaning. This design avoids slurry settling caused by a shutdown of the entire feeding system.

[0137] 4. Resume coating: After cleaning or rinsing, reinstall the die head 8 (or remove the sealing tape). The host computer can directly switch the second three-way valve 7 to the "coating" mode, and the system will quickly resume stable coating, greatly reducing the production capacity loss and slurry waste caused by traditional shutdown cleaning.

[0138] Through the above operating methods, this system achieves intelligent, continuous, and highly reliable operation of the silicon-based anode slurry coating process. Example 3

[0139] This embodiment provides a control method based on the coating feeding system described in Embodiment 2, including the following steps: After the entire feeding system is initially running, the slurry flow is switched to the external circulation pipeline 11 via the second three-way valve 7. The slurry flows into the first buffer tank 3, and then is extracted by the continuous defoamer 41 for defoaming treatment before flowing into the second buffer tank 6. At this time, the slurry in the main feeding pipeline 9 is further processed by the scraper filter, the Nennis filter, and the demagnetizing device, and continuously circulated. This method can stabilize the pressure of the entire feeding system before entering the die head, and the slurry state can be initially stabilized after being buffered by the second buffer tank 6, so that the cavity pressure after the slurry enters the die head is relatively stable, reducing waste caused by unstable cavity pressure during the initial coating process. After circulating for a period of time, the slurry flow is switched to the die head 8 via the second three-way valve 7, and the slurry is sprayed onto the foil through the spray nozzle 81 to form an electrode in a wet film state. This can solve the foil leakage phenomenon caused by gas generation in silicon-based anodes, eliminate the production capacity bottleneck of silicon-based anodes in the coating process, and greatly improve production capacity.

[0140] In some embodiments, after a short stop in the coating process, the nozzle 81 of the die head 8 can be sealed with tape, and the slurry in the cavity can flow into the external circulation pipeline 11 through the overflow port 82 of the die head 8, so that the slurry in the die head 8 remains in a flowing state, preventing the slurry from settling and agglomerating to produce particles.

[0141] In some embodiments, when the coating process requires cleaning due to a large number of slurry particles inside the die head 8, the slurry can be circulated into the external circulation pipeline 11 through the second three-way valve 7 to prevent the slurry inside the feeding system from settling due to the shutdown of the feeding system.

[0142] Based on the above coating feeding system, the present invention provides a feeding system control method, including a feeding system coating start-up and process control method S1 and a feeding system abnormality control method S2, which can ensure that air bubbles in the slurry are completely eliminated and that the dimensional areal density of the coating process is stable.

[0143] The material feeding system coating start-up and process control method S1 includes the following steps: S11: The equipment starts up. The first liquid level sensor 31 detects that the liquid level in the first buffer tank 3 is lower than the lower limit and requests the host computer to start feeding. S12: The host computer controls the electric ball valve 2 to open, and the slurry continuously flows into the first buffer tank 3 through the main feed port 34; S13: The host computer sends a command to start the defoaming unit 41, and draws the slurry from the main discharge port 35 into the defoaming machine 4 to defoam the slurry; S14: The host computer initiates the "deaerator self-circulation" command; In step S14, the “defoamer self-circulation” command is activated, which means switching the pipeline of the first three-way valve 3 so that the slurry flows into the first buffer tank 3 through the self-circulation pipeline 10 and the self-circulation return port 36. Through steps S11-S14, on the one hand, the slurry with poor defoaming effect due to insufficient vacuum pressure of the equipment can be effectively recycled and reused; on the other hand, the fluctuation range of the defoamed slurry is controlled within ±2℃ by the chiller unit 4, so as to ensure that the viscosity of the subsequent slurry will not be further affected by temperature fluctuations, thus affecting the pressure inside the die head 8.

[0144] S15: When the vacuum pressure inside the defoamer 41 reaches the specified parameter, the host computer closes the "defoaming self-circulation" command; In step S15, the "defoaming self-circulation" command is turned off, which controls the first three-way valve 3 to switch the pipeline, and the slurry flows into the second buffer tank 6 through the main feed pipeline 9 and the feed port 64; S16: The host computer initiates the "feeding system cycle" command; In step S16, the “feeding system circulation” command is activated, which means switching the pipeline flow direction of the second three-way valve 7 to the first buffer tank 3. The screw pump draws the slurry in the first buffer tank 6 through the discharge port 65, through the scraper filter, the Nen filter and the demagnetizing device, and finally through the external circulation pipeline 11 and into the first buffer tank 3 from the external circulation return port 37. S17: After the pressure of the material feeding system is detected to be stable, the host computer closes the "material feeding system circulation" command and starts the "coating" command; In step S17, the "coating" command is activated, which means switching the flow direction of the second three-way valve 7 to the die head 8, and coating is carried out through the spray port 81 of the die head 8. When the pressure in the cavity of the die head 8 is too high, the slurry is depressurized from the overflow port 82 of the die head 8.

[0145] In steps S15-S17, the pressure of the entire feeding system tends to stabilize before the slurry enters the die head 8, thus avoiding the waste caused by the slurry being directly output through the die head 8.

[0146] S18: When the liquid level of the second buffer tank 6 reaches the set upper limit, the second liquid level sensor 61 sends a signal to the host computer, and the host computer starts the "deaerator self-circulation" command.

[0147] S19: When the liquid level in the second buffer tank 6 reaches the set lower limit, the second liquid level sensor 61 sends a signal to the host computer. The host computer closes the "defoamer self-circulation" command and controls the first three-way valve 3 to switch the pipeline, so that the slurry flows into the second buffer tank 6 through the main feed pipeline 9 and the feed port 64.

[0148] In steps S18-S19, by adjusting the upper and lower limits of the liquid level, the influence of the liquid level change in the second buffer tank 6 on the stability of the cavity pressure of subsequent material supply during the screw pump pumping process can be effectively controlled.

[0149] The abnormal control method S2 for the material feeding system includes the following steps: S21: When frequent scraping or numerous particle marks occur during the coating process, a die retraction command is issued via the host computer. S22: Initiate the "Feeding System Cycle" command via the host computer, clean the ejector nozzle 81 of the die head 8, and seal the ejector nozzle with tape. S23: The host computer closes the "feeding system circulation" command, opens the "coating" command, and switches the pipeline flow direction of the second three-way valve 7 to the die head 8. In step S23, since the nozzle 81 is sealed, the slurry flows through the overflow port 82 and the external circulation pipe 11 into the first buffer tank 3 via the external circulation return port 37, continuously forming the slurry circulation of the entire feeding system.

[0150] Through steps S21-S23, the particles in the die head 8 are effectively filtered through the scraper filter and nacelle filter in the entire feeding system.

[0151] S24: Remove the sealing tape from the nozzle 81 and start coating. If scratches or particles continue to appear, the host computer will activate the "feeding system circulation" command and open the die head 8 for deep cleaning.

[0152] S25: After cleaning is complete, activate the "coating" command.

[0153] Steps S24-S25 clean the die head, solving the particle problem caused by deep settling inside the die head. At the same time, the entire feeding system remains in a flowing state, preventing the agglomeration and settling of slurry in the entire feeding system pipeline from further generating particles.

[0154] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature, and in the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0155] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0156] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0157] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0158] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A coating and feeding system based on lithium battery silicon-based anode slurry, characterized in that, It includes a mixing transfer tank (1), a first buffer tank (3), a defoaming unit (4), a first three-way valve (5), a second buffer tank (6), a second three-way valve (7), and a die head (8) that are connected in sequence through the main feeding pipeline (9); The first buffer tank (3) is connected to the first three-way valve (5) through a self-circulation pipeline (10); the first buffer tank (3) is connected to the second three-way valve (7) through an external circulation pipeline (11); The first three-way valve (5) is used to switch the slurry from the defoaming unit (4) to the second buffer tank (6) or return it to the first buffer tank (3) via the self-circulation pipeline (10); The second three-way valve (7) is used to switch the slurry from the second buffer tank (6) to the die head (8) or return it to the first buffer tank (3) via the external circulation pipeline (11); The die head (8) is used to spray material outwards.

2. The coating and feeding system based on lithium battery silicon-based anode slurry according to claim 1, characterized in that, The first buffer tank (3) is provided with a main feed inlet (34), a main discharge outlet (35), a self-circulating return outlet (36) and an external circulation return outlet (37); The first three-way valve (5) and the second three-way valve (7) are both provided with an inlet, an outlet 1 and an outlet 2; The discharge port of the mixing transfer tank (1) is connected to the main inlet (34) of the first buffer tank (3); The main outlet (35) of the first buffer tank (3) is connected to the inlet of the defoaming unit (4); the self-circulation return port (36) of the first buffer tank (3) is connected to the outlet of the first three-way valve (5) through the self-circulation pipeline (10); the external circulation return port (37) of the first buffer tank (3) is connected to the outlet of the second three-way valve (7) through the external circulation pipeline (11); The outlet of the defoaming unit (4) is connected to the inlet of the first three-way valve (5); the outlet of the first three-way valve (5) is connected to the inlet (64) of the second buffer tank (6); the outlet (65) of the second buffer tank (6) is connected to the inlet of the second three-way valve (7); and the outlet of the second three-way valve (7) is connected to the die head (8).

3. The coating and feeding system based on lithium battery silicon-based anode slurry according to claim 1, characterized in that, The die head (8) is provided with a spray nozzle (81) and an overflow port (82) connected to the external circulation pipeline (11); the spray nozzle (81) is used to spray material outward.

4. The coating and feeding system based on lithium battery silicon-based anode slurry according to claim 1, characterized in that, The defoaming unit (4) includes a continuous defoaming machine (41), a vacuum pump (42), and a vacuum tank (43); The inlet of the continuous defoamer (41) is connected to the main outlet (35) of the first buffer tank (3), and the outlet is connected to the inlet (64) of the second buffer tank (6). The vacuum pump (42) is connected to the vacuum chamber of the continuous defoamer (41) through the vacuum tank (43); The defoaming unit (4) also includes a cooling device; the cooling device is used to cool the continuous defoaming machine (41) and its output slurry; The cooling device includes a chiller (44) and a cooling water pipeline (45), the cooling water pipeline (45) forming a jacket structure that surrounds the feed pipeline between the outlet of the continuous defoamer (41) and the first three-way valve (5); The end of the cooling water pipe (45) is connected to the drive unit of the continuous defoamer (41).

5. The coating and feeding system based on lithium battery silicon-based anode slurry according to claim 1, characterized in that, The second buffer container (6) is equipped with a splash-proof device (67).

6. The coating and feeding system based on lithium battery silicon-based anode slurry according to claim 5, characterized in that, The anti-splash device (67) includes a baffle disposed around the inside of the feed inlet (64) of the second buffer tank; the highest point of the baffle is higher than the feed inlet (64) of the second buffer tank.

7. The coating and feeding system based on lithium battery silicon-based anode slurry according to claim 6, characterized in that, The system also includes a host computer; An electric ball valve (2) is provided between the slurry transfer tank (1) and the first buffer tank (3) to control the slurry output of the slurry transfer tank (1); The first buffer tank (3) is equipped with a first liquid level sensor (31) for acquiring the liquid level signal in the first buffer tank (3); The second buffer tank (6) is provided with a second liquid level sensor (61) for acquiring the liquid level signal in the second buffer tank (6); The host computer is connected to the electric ball valve (2), the first liquid level sensor (31), the second liquid level sensor (61), the first three-way valve (5), and the second three-way valve (7) respectively, and is used to control the liquid circuit switching and on / off of the electric ball valve (2), the first three-way valve (5), and the second three-way valve (7) according to the liquid level signal in the first buffer tank (3) and the liquid level signal in the second buffer tank (6).

8. The coating and feeding system based on lithium battery silicon-based anode slurry according to claim 1, characterized in that, The first buffer tank (3) is equipped with a first stirring device (33) and a first float device (32); The second buffer tank (6) is equipped with a second stirring device (63) and a second float device (62); The first stirring device (33) and the second stirring device (63) are both used to stir the slurry in the tank; Both the first float device (32) and the second float device (62) are used to prevent the slurry from overflowing.

9. A control method for the coating feeding system according to any one of claims 1-8, characterized in that, This includes the coating start-up control process of the material supply system, which includes the following steps: Start the defoaming unit (4) to defoam the slurry drawn from the first buffer tank (3); The flow direction of the slurry is controlled by the first three-way valve (5), so that the deaerated slurry flows back to the first buffer tank (3) for deaeration self-circulation; When the vacuum level inside the defoaming unit (4) reaches the set value, the flow direction of the slurry is controlled by the first three-way valve (5), and the defoamed slurry is switched and transported to the second buffer tank (6); The flow direction of the slurry is controlled by the second three-way valve (7), so that the slurry flows out of the second buffer tank (6) and flows back to the first buffer tank (3) to circulate the feeding system; Once the system pressure stabilizes, the slurry flow direction is controlled by the second three-way valve (7), and the slurry is switched and delivered to the die head (8) for coating.

10. The control method according to claim 9, characterized in that, Also includes: When coating abnormalities occur, perform the following steps: Control the die head (8) to retract and seal its nozzle (81); The flow direction of the slurry is controlled by the second three-way valve (7), so that the slurry in the system continuously flows back to the first buffer tank (3); After cleaning or washing the die head (8), resume coating.

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