A high-precision die for precisely controlling the flow rate of slurry

Abstract

A kind of high-precision die for precisely controlling slurry flow rate, it is related to lithium ion battery manufacturing equipment technical field, including lower die, and upper die being arranged above lower die, it is characterized by: the lower die and upper die form slurry passage by detachable connection mode, the passage includes feed inlet, distribution cavity and discharge slit, the upper side of the upper die is equipped with on-line viscosity detection instrument, the on-line viscosity detection instrument includes sensor module, signal processing module and data transmission module, its detection end is embedded in the distribution cavity side wall by sealing structure, on-line viscosity detection instrument side is equipped with gap adjustment unit, it is configured to dynamically adjust the gap between the upper die and lower die according to the viscosity value of each detection point, the present scheme solves the problem that flow instability is caused by the viscosity variation of slurry in the die in the prior art, and then affects the consistency of area density.

Description

Technical Field

[0001] This utility model relates to the field of lithium-ion battery manufacturing equipment technology, specifically a high-precision die head for precisely controlling the flow rate of slurry. Background Technology

[0002] In the manufacturing process of lithium-ion batteries, coating is a crucial step, its function being to uniformly coat the positive or negative electrode slurry onto the metal current collector. The consistency of the coating areal density has a direct and critical impact on battery performance and consistency, and the coating die, as the core equipment affecting areal density consistency, plays a decisive role in its precision. A high-precision die can accurately control the areal density, thereby improving battery performance and consistency; therefore, a high-precision die is required in the coating process.

[0003] Currently, there are two main control methods for coating dies. One method involves manually adjusting the balance nut or dial indicator to ensure uniformity of the areal density based on variations. The other method, with advancements in coating technology, employs closed-loop control to replace manual adjustment. While closed-loop control has achieved some degree of automatic areal density control and improved areal density uniformity, it has not completely and effectively solved the problem.

[0004] This is because lithium battery slurry is a non-Newtonian fluid, and its properties change with shear rate. The inconsistent shear rate of the slurry at different lateral positions of the die head leads to variations in its rheology and viscoelasticity. Closed-loop automated devices can only roughly control the slurry flow rate. Furthermore, areal density measuring instruments are typically installed at the oven exit position after coating and baking, which is far from the coating die head. When abnormal areal density adjustments occur, at least one oven's worth of defective electrodes will be produced, hindering yield improvement. Therefore, this does not meet current requirements. To address this, we propose a high-precision die head for precise control of slurry flow rate. Utility Model Content

[0005] The purpose of this invention is to provide a high-precision die head that precisely controls the flow rate of slurry, so as to solve the problem mentioned in the background art where the flow rate is unstable due to the change in the viscosity of the slurry inside the die head, which in turn affects the consistency of the surface density.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a high-precision die head for precisely controlling slurry flow rate, comprising a lower die head and an upper die head disposed above the lower die head. The lower die head and the upper die head are detachably connected to form a slurry channel, the channel comprising an inlet, a distribution cavity, and an outlet slit. An online viscosity testing instrument is installed above the upper die head. The online viscosity testing instrument comprises a sensor module, a signal processing module, and a data transmission module. Its detection end is embedded in the side wall of the distribution cavity through a sealing structure. A gap adjustment unit is installed on one side of the online viscosity testing instrument, which is configured to dynamically adjust the gap between the upper die head and the lower die head according to the viscosity value at each detection point.

[0007] Preferably, the sensor module of the online viscosity testing instrument adopts a coaxial cylindrical structure, including an inner cylinder rotor, an outer cylinder stator and a torque detection unit. The inner cylinder rotor is connected to the drive motor through magnetic coupling, and the outer cylinder stator is flush with the inner wall of the slurry channel.

[0008] Preferably, the die head gap adjustment unit includes an independently driven fine-tuning mechanism. The fine-tuning mechanism adopts a lead screw and nut pair driven by a servo motor. The lead screw and nut pair is connected to the upper die head. The signal output terminal of the online viscosity testing instrument is connected to a controller, and the output terminal of the controller is connected to the die head gap adjustment unit.

[0009] Preferably, the online viscosity testing instrument has a detection frequency of 10-50Hz, and the response time of the die head gap adjustment unit is ≤200ms.

[0010] Preferably, the online viscosity testing instrument is equipped with a linear drive mechanism for sequentially detecting the viscosity of slurry at different locations. The preset detection points are arranged at a spacing of 50-200mm along the transverse direction of the die head, and detection points are provided at least at both ends and the middle of the die head. The moving path of the online viscosity testing instrument covers all preset detection points.

[0011] Compared with the prior art, the beneficial effects of this utility model are:

[0012] 1. This invention, by installing online viscosity detection instruments at different lateral positions on the die head, can capture subtle changes in slurry viscosity in real time and dynamically respond using a die head gap adjustment unit. This solves the problem of unstable flow rate caused by slurry viscosity fluctuations in traditional dies. Compared to existing technologies that rely on manual adjustment or coarse closed-loop control, this design achieves precise control of slurry flow rate, ensuring that the slurry flow state remains consistent across all lateral positions on the die head. This fundamentally improves the uniformity of coating surface density and lays a solid foundation for the stability of battery performance.

[0013] 2. This invention integrates closed-loop control of viscosity detection and gap adjustment within the die head. The adjustment action can directly act on the flowing slurry, avoiding the lag problem caused by the detection point being far from the coating area in traditional technologies. When the slurry characteristics change, this invention can complete the gap adjustment in a very short time without waiting for feedback from downstream detection equipment, thereby minimizing the number of defective electrodes caused by untimely adjustment and significantly reducing material waste in the production process.

[0014] 3. This invention addresses the non-Newtonian fluid characteristics of lithium battery slurry. By detecting viscosity in different zones and adjusting the gap accordingly, it effectively balances the differences in slurry shear rates at different lateral positions of the die head. This refined control method ensures that regardless of how the slurry flows within the die head, changes in its rheology and viscoelasticity can be corrected in a timely manner, guaranteeing a highly consistent state of the slurry when coated onto the current collector. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0016] Figure 2 This is a schematic diagram of the die head gap adjustment unit structure of this utility model;

[0017] Figure 3 This is a schematic diagram of the structure of the online viscosity testing instrument of this utility model;

[0018] In the diagram: 1. Lower die head; 2. Upper die head; 3. Die head gap adjustment unit; 4. Online viscosity testing instrument. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0020] Please see Figure 1-3 The present invention provides an embodiment of a high-precision die head for precisely controlling the flow rate of slurry, comprising a lower die head 1 and an upper die head 2 disposed above the lower die head 1. The lower die head 1 and the upper die head 2 are detachably connected to form a slurry channel, which includes an inlet, a distribution cavity, and an outlet slit. An online viscosity testing instrument 4 is installed above the upper die head 2. The online viscosity testing instrument 4 includes a sensor module, a signal processing module, and a data transmission module. Its detection end is embedded in the side wall of the distribution cavity through a sealing structure. A gap adjustment unit 3 is installed on one side of the online viscosity testing instrument 4, which is configured to dynamically adjust the gap between the upper die head 2 and the lower die head 1 according to the viscosity value of each detection point.

[0021] When the slurry from the buffer tank of the coating trolley passes through the cavity between the upper die head 2 and the lower die head 1, the slurry flows to different positions on the die head. The flow rate of the slurry is different at different lateral positions on the die head, which causes the viscosity of the slurry to change. At this time, the online viscosity detection instrument 4 detects the viscosity change in real time and feeds it back to the die head gap adjustment unit 3. The die head gap adjustment unit 3 makes adjustments according to the viscosity change detected by the online viscosity detection instrument 4. When the viscosity is too high, the die head gap adjustment unit 3 increases the die head gap; when the viscosity is too low, the die head gap adjustment unit 3 decreases the die head gap. It always dynamically maintains the flow rate of the slurry at different lateral positions on the die head, thereby achieving a consistent slurry flow rate and maintaining the stability of the areal density and dimensions.

[0022] Furthermore, the sensor module of the online viscosity analyzer 4 adopts a coaxial cylindrical structure, including an inner cylinder rotor, an outer cylinder stator, and a torque detection unit. The inner cylinder rotor is connected to the drive motor via magnetic coupling, and the outer cylinder stator is flush with the inner wall of the slurry channel. The drive motor drives the inner cylinder rotor to rotate in the slurry via magnetic coupling. The viscous resistance of the slurry acts on the inner cylinder rotor, causing a change in torque. The torque detection unit converts this change into an electrical signal and calculates the slurry viscosity by measuring the relationship between torque and rotational speed.

[0023] Furthermore, the die head gap adjustment unit 3 includes an independently driven fine-tuning mechanism. This mechanism employs a servo motor-driven screw and nut assembly, which is connected to the upper die head 2. The signal output of the online viscosity measuring instrument 4 is connected to a controller, and the controller's output is connected to the die head gap adjustment unit 3. After receiving viscosity data from the online viscosity measuring instrument 4, the controller calculates the adjustment amount of the fine-tuning mechanism at the corresponding position based on the viscosity deviation at each measuring point using a PID algorithm. The servo motor-driven screw and nut assembly converts rotational motion into linear motion, precisely adjusting the local height of the upper die head 2, thereby changing the local width of the discharge slit and achieving independent control of the slurry flow rate at different positions.

[0024] Furthermore, the online viscosity testing instrument 4 has a detection frequency of 10-50Hz, the response time of the die head gap adjustment unit 3 is ≤200ms, and the online viscosity testing instrument 4 is equipped with a linear drive mechanism for sequentially detecting the viscosity of the slurry at different positions. The preset detection points are arranged at a spacing of 50-200mm along the transverse direction of the die head, and detection points are provided at least at both ends and the middle of the die head. The moving path of the online viscosity testing instrument 4 covers all preset detection points. The linear drive mechanism drives the online viscosity testing instrument 4 to move laterally along the die head, stopping sequentially at the preset detection point positions and collecting viscosity data. Based on the viscosity values ​​of each detection point, the controller generates a continuous viscosity distribution curve in the transverse direction of the die head through an interpolation algorithm, and then calculates the required gap adjustment amount at each position.

[0025] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A high-precision die head for precisely controlling the flow rate of slurry, comprising a lower die head (1) and an upper die head (2) disposed above the lower die head (1), characterized in that: The lower die head (1) and the upper die head (2) are connected in a detachable manner to form a slurry channel. The channel includes an inlet, a distribution cavity and an outlet slit. An online viscosity testing instrument (4) is installed above the upper die head (2). The online viscosity testing instrument (4) includes a sensor module, a signal processing module and a data transmission module. Its detection end is embedded in the side wall of the distribution cavity through a sealing structure. A gap adjustment unit (3) is installed on one side of the online viscosity testing instrument (4). It is configured to dynamically adjust the gap between the upper die head (2) and the lower die head (1) according to the viscosity value of each detection point.

2. The high-precision die head for precisely controlling slurry flow rate according to claim 1, characterized in that: The sensor module of the online viscosity testing instrument (4) adopts a coaxial cylindrical structure, including an inner cylinder rotor, an outer cylinder stator and a torque detection unit. The inner cylinder rotor is connected to the drive motor through magnetic coupling, and the outer cylinder stator is flush with the inner wall of the slurry channel.

3. The high-precision die head for precisely controlling slurry flow rate according to claim 1, characterized in that: The die head gap adjustment unit (3) includes an independently driven fine-tuning mechanism. The fine-tuning mechanism adopts a lead screw and nut pair driven by a servo motor. The lead screw and nut pair is connected to the upper die head (2). The signal output terminal of the online viscosity testing instrument (4) is connected to a controller, and the output terminal of the controller is connected to the die head gap adjustment unit (3).

4. The high-precision die head for precisely controlling slurry flow rate according to claim 3 and claim 1, characterized in that: The online viscosity testing instrument (4) has a detection frequency of 10-50Hz, and the response time of the die head gap adjustment unit (3) is ≤200ms.

5. A high-precision die head for precisely controlling slurry flow rate according to claim 1, characterized in that: The online viscosity testing instrument (4) is equipped with a linear drive mechanism for sequentially detecting the viscosity of slurry at different positions. The preset detection points are arranged at a spacing of 50-200mm along the transverse direction of the die head, and detection points are provided at least at both ends and the middle of the die head. The moving path of the online viscosity testing instrument (4) covers all preset detection points.

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