Coating system

Abstract

This application provides a coating system comprising a tank, a coating module, an air knife structure, and a first heating structure. The tank is used to contain slurry. The coating module is connected to the tank and is used to coat the slurry onto a current collector. The air knife structure is located downstream of the coating module along the conveying direction of the current collector and is used to blow air onto the slurry on the current collector. The first heating structure is used to heat the slurry located between the air knife structure and the tank along the conveying direction of the current collector. The gas blown out by the air knife structure can generate downward pressure on the slurry, which can cause the slurry to flow on the current collector. The increased temperature of the slurry increases its fluidity. Therefore, the first heating structure and the air knife structure jointly improve the fluidity of the slurry, improve the leveling of the slurry on the current collector, thereby improving the coating consistency, the uniformity of the coating thickness, and the coating efficiency of the coating system.

Description

Technical Field

[0001] This application relates to the field of battery slurry coating technology, and more particularly to a coating system. Background Technology

[0002] As the requirements for battery production efficiency in the new energy sector gradually increase, the requirements for electrode sheet production efficiency also gradually increase. In the electrode sheet coating slurry process, increasing the solid content of the slurry can improve the production efficiency of the electrode sheet. However, increasing the solid content of the slurry will lead to an increase in viscosity and a decrease in fluidity, resulting in uneven leveling of the slurry coating on the current collector and poor coating consistency. Utility Model Content

[0003] This application provides a coating system to solve the problem of poor coating consistency that occurs when the solid content of the slurry is increased.

[0004] This application provides a coating system comprising a tank, a coating module, an air knife structure, and a first heating structure. The tank is used to contain a slurry. The coating module is connected to the tank and is used to coat the slurry onto a current collector. The air knife structure is located downstream of the coating module along the conveying direction of the current collector and is used to blow air onto the slurry on the current collector. The first heating structure is used to heat the slurry located between the air knife structure and the tank along the conveying direction of the current collector.

[0005] In some embodiments, the coating system further includes an adjustment roller located downstream of the coating module along the conveying direction of the current collector and close to the air knife structure. The adjustment roller and the air knife structure are located on different sides of the current collector, and the current collector located between the adjustment roller and the coating module is arranged at an angle to the horizontal direction.

[0006] In some embodiments, the first heating structure is used to heat at least one of the current collector located between the tank, the coating module, the air knife structure, the regulating roller, the coating module, and the air knife structure.

[0007] In some embodiments, the angle between the current collector located between the regulating roller and the coating module and the horizontal direction is 45°-75°.

[0008] In some embodiments, the distance between the adjusting roller and the coating module in the horizontal direction is adjustable to adjust the angle between the current collector located between the adjusting roller and the coating module and the horizontal direction.

[0009] In some embodiments, the portion of the adjusting roller that is in contact with the current collector forms a contact area, and the air outlet of the air knife structure is disposed opposite to the contact area.

[0010] In some embodiments, the position of the air outlet of the air knife structure relative to the adjusting roller can be adjusted to adjust the air outlet direction of the air knife structure and / or the distance between the air outlet of the air knife structure and the adjusting roller.

[0011] In some embodiments, the heating temperature of the first heating structure is 40°C-60°C.

[0012] In some embodiments, the coating system further includes a second heating structure for heating the slurry located after the air knife structure along the conveying direction of the current collector.

[0013] In some embodiments, the coating system further includes a baffle plate disposed between the air knife structure and the coating module, wherein the distance between the baffle plate and the current collector is less than a preset value; and / or, the coating system further includes a negative pressure structure disposed between the air knife structure and the coating module.

[0014] In the coating system provided in this application, on the one hand, the slurry coated on the current collector by the coating module is blown with air based on the air knife structure. The air blown out by the air knife structure can generate downward pressure on the slurry, which can promote the flow of the slurry on the current collector. On the other hand, the slurry is heated based on the first heating structure. After the temperature of the slurry increases, the fluidity of the slurry increases. Thus, the fluidity of the slurry is improved by the first heating structure and the air knife structure, the leveling degree of the slurry on the current collector is improved, and the coating consistency of the slurry is improved, the uniformity of the coating thickness of the slurry is improved, and the coating efficiency of the coating system is improved. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the coating system provided in the embodiments of this application.

[0017] Figure 2 This is a schematic diagram showing the relative positions of the air knife structure and the adjusting roller provided in some embodiments of this application.

[0018] Figure 3This is a schematic diagram of the coating system provided in some embodiments of this application.

[0019] Figure 4 This is a table of coating experiment data for electrode sheets prepared by a conventional coating system and the coating system described in the embodiments of this application.

[0020] Key reference numerals: Coating system 100; Current collector 101; Tank 10; Coating module 20; Coating die 21; Coating roller 22; Air knife structure 30; Air outlet 301; First heating structure 40; Adjusting roller 50; Bonding area 501; Second heating structure 61; Baffle plate 621; Negative pressure structure 622; Surface density detection structure 63; Conveying roller 64; Angle α; Horizontal direction X; Air outlet direction F.

[0021] The following detailed description, in conjunction with the accompanying drawings, will further illustrate this application. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0023] In this document, references to "embodiment" or "implementation" mean that a particular feature, structure, or characteristic described in connection with an embodiment or implementation may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0024] It should be noted that the terminology in the specification, claims, and accompanying drawings of this application is for describing specific embodiments only and is not intended to limit this application. The terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish different objects, not to describe a specific order. The term "and / or" as used in this application refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations.

[0025] In this embodiment, when the coating system 100 conveys the current collector 101, the current collector 101 is conveyed from upstream to downstream along the conveying direction. Component A being upstream of component B along the conveying direction of the current collector 101 means that the current collector 101 passes through component A first, then component B during conveying. Component C being downstream of component D means that the current collector 101 passes through component D first, then component C during conveying.

[0026] Please see Figure 1 , Figure 1 This is a schematic diagram of the coating system 100 provided in this application embodiment. The coating system 100 is applied in the field of battery slurry coating technology. The coating system 100 is used to coat battery slurry onto a current collector 101 to produce electrode sheets. The coating system 100 includes a tank 10, a coating module 20, an air knife structure 30, and a first heating structure 40. The tank 10 is used to contain the slurry. The coating module 20 is connected to the tank 10 and is used to coat the slurry in the tank 10 onto the current collector 101. The air knife structure 30 is located downstream of the coating module 20 along the conveying direction of the current collector 101 (i.e., the current collector 101 passes through the coating module 20 first and then through the air knife structure 30), and is used to blow air onto the slurry on the current collector 101. The air knife structure 30 is used to blow out a high-intensity, narrow-width airflow, so that the airflow forms a thin, high-speed air curtain similar to a blade in the outlet direction. The first heating structure 40 is used to heat the slurry located between the air knife structure 30 and the tank 10 along the conveying direction of the current collector 101.

[0027] Traditional low-solids slurries typically have a solids content (the percentage of solids remaining after solvent removal) between 60% and 68% and a viscosity between 6000 mPa·s and 13000 mPa·s. Low-solids slurries exhibit good flowability during coating, allowing for automatic leveling on the current collector after coating (the slurry flows automatically and gradually forms a smooth, uniform film due to its surface tension and gravity), resulting in good coating consistency and uniform coating thickness. However, the higher solvent content in low-solids slurries necessitates longer drying times and oven times, hindering the production efficiency of electrode sheets. Increasing the solids content of the slurry can improve the production efficiency of electrode sheets. High-solids content slurries typically have a solids content between 70% and 75%, and a viscosity between 15,000 mPa·s and 35,000 mPa·s. The viscosity of high-solids content slurries is significantly higher than that of low-solids content slurries, leading to poorer fluidity, slower and more difficult leveling, and, with increasing coating speed, shorter leveling time. This results in uneven leveling of the slurry on the manifold, leading to poor coating consistency.

[0028] In this embodiment, on the one hand, the air knife structure 30 blows air onto the slurry coated by the coating module 20 onto the collector 101. The air blown out by the air knife structure 30 can generate downward pressure on the slurry, which can promote the flow of the slurry on the collector 101. On the other hand, the slurry is heated by the first heating structure 40. The increase in the temperature of the slurry can increase the fluidity of the slurry. Thus, the fluidity of the slurry is improved by the first heating structure 40 and the air knife structure 30, thereby improving the leveling speed and leveling degree of the slurry on the collector 101, and further improving the coating consistency of the slurry, improving the uniformity of the coating thickness of the slurry, and improving the coating efficiency of the coating system 100.

[0029] Figure 1 The structure of the coating system 100 illustrated in this embodiment is merely a schematic diagram and does not constitute a specific limitation on the coating system 100. In other embodiments of this application, the coating system 100 may include... Figure 1 The coating system 100 may include more or fewer components, or combinations of certain components, or different components, such as an unwinding device, an oven, etc. For example, in an embodiment of this application, the coating system 100 may also include an oven disposed downstream of the air knife structure 30 along the conveying direction of the current collector 101, and the oven is used to dry the slurry on the current collector 101.

[0030] In this embodiment, the coating speed of the coating system 100 is between 60 m / min and 90 m / min. Compared with traditional coating systems, the coating system 100 in this embodiment, by setting the first heating structure 40 and the air knife structure 30, can improve the coating speed of the slurry while ensuring the coating consistency meets production requirements, achieving high-speed coating and thus improving the production efficiency of the electrode sheets. The coating speed of the coating system 100 can be specifically set according to factors such as the solid content of the slurry, the heating temperature of the first heating structure 40, and the airflow rate of the air knife structure 30, and is not specifically limited in this application. For example, the coating speed of the coating system 100 can be 60 m / min, 65 m / min, 70 m / min, 75 m / min, 80 m / min, 85 m / min, 90 m / min, etc.

[0031] The coating system 100 also includes an adjusting roller 50. The adjusting roller 50 is located downstream of the coating module 20 along the conveying direction of the current collector 101 and is positioned close to the air knife structure 30. The adjusting roller 50 and the air knife structure 30 are located on different sides of the current collector 101. The adjusting roller 50 is used to convey the current collector 101, adjust the conveying direction of the current collector 101, and support the current collector 101 to reduce the degree of vibration of the current collector 101 when the air knife structure 30 blows on it, thereby improving the thickness uniformity of the slurry after leveling.

[0032] The current collector 101, located between the adjusting roller 50 and the coating module 20, is positioned at an angle α to the horizontal direction X. Thus, gravity exerts an inclined component force on the slurry parallel to the conveying direction of the current collector. This inclined component force facilitates the automatic leveling of the slurry on the current collector 101 under the action of gravity, thereby improving the leveling degree of the slurry. For the sake of accuracy, this application uses... Figure 1 The X-axis direction is defined as the horizontal direction, which is parallel to the horizontal plane.

[0033] When coating traditional low-solids slurries, the included angle α usually needs to be less than 45° due to the slurry's high fluidity to avoid localized unevenness caused by flow. However, this results in an excessively long current collector between the conditioning roller and the coating module, leading to an increase in the overall volume of the coating system and low space utilization.

[0034] In this embodiment, the angle α between the current collector 101 located between the adjusting roller 50 and the coating module 20 and the horizontal direction X is 45°-75°. The angle α in this embodiment, being between 45° and 75°, improves the flowability of the slurry on the current collector 101 between the adjusting roller 50 and the coating module 20, facilitating automatic leveling of the slurry under gravity. It also reduces the length of the current collector 101 between the adjusting roller 50 and the coating module 20, improving the conveying stability of the current collector 101, and reducing the volume of the coating system 100, thereby increasing the space utilization of the coating system 100 and making its structure more compact. When the included angle α is less than 45°, the inclination of the current collector 101 is too small, which is not conducive to the leveling of the slurry under gravity, and will increase the length of the current collector 101 located between the adjusting roller 50 and the coating module 20, which is not conducive to the stable transmission of the current collector 101, and will result in low space utilization of the coating system 100, which is not conducive to the miniaturization of the coating system 100. When the included angle α is greater than 75°, the inclination of the current collector 101 is too large, and the slurry is prone to excessive flow under gravity, which will easily lead to local unevenness of the slurry. The specific value of the included angle α can be set according to actual needs, and is not specifically limited in this application. For example, the included angle α can be 45°, 46°, 48°, 50°, 52°, 54°, 55°, 56°, 58°, 60°, 62°, 64°, 65°, 66°, 68°, 70°, 72°, 74°, 75°, etc.

[0035] In some embodiments, the distance between the adjusting roller 50 and the coating module 20 along the horizontal direction X is adjustable to adjust the angle α between the current collector 101 located between the adjusting roller 50 and the coating module 20 and the horizontal direction. This allows the angle α to be adjusted according to actual production conditions during the assembly and debugging of the coating system 100, thereby improving the ease of use and adaptability of the coating system 100 to production conditions. Specifically, when the adjusting roller 50 moves closer to the coating module 20 along the horizontal direction X, the angle α increases; when the adjusting roller 50 moves further away from the coating module 20 along the horizontal direction X, the angle α decreases.

[0036] In this embodiment, the air outlet 301 of the air knife structure 30 is positioned opposite to the adjusting roller 50. The portion of the adjusting roller 50 that contacts the current collector 101 forms a contact area 501. The air outlet 301 of the air knife structure 30 is positioned opposite to the contact area 501. The contact area 501 is... Figure 1 The two dashed lines correspond to the acute angle region. In the bonding area 501, the collector 101 is bonded to the outer axial surface of the adjusting roller 50. Thus, when the air knife structure 30 blows air onto the collector 101, the airflow from the air knife structure 30 acts on the bonding area 501, and the outer axial surface of the adjusting roller 50 can support the collector 101 to prevent it from shaking. This improves the uniformity of the pressure of the air blown by the air knife structure 30 on the slurry on the collector 101, thereby improving the thickness uniformity of the slurry leveling and the consistency of the slurry coating.

[0037] In some embodiments, the air outlet 301 of the air knife structure 30 can also be offset from the adjusting roller 50, and the air outlet 301 of the air knife structure 30 can be offset from the bonding area 501, so as to facilitate the specific setting of the installation position of the air knife structure 30 according to the structure of the coating system 100, avoid structural interference, and reduce the assembly difficulty of the air knife structure 30.

[0038] In some embodiments, the current collector 101, located after the air knife structure 30 along the conveying direction of the current collector 101, is inclined towards the ground to increase the angle range corresponding to the contact area 501 on the adjusting roller 50, thereby improving the support effect of the adjusting roller 50 on the current collector 101 and improving the coating uniformity of the slurry. In some embodiments, the current collector 101, located after the air knife structure 30 along the conveying direction of the current collector 101, may also be inclined towards the direction away from the ground. In some embodiments, the current collector 101, located after the air knife structure 30 along the conveying direction of the current collector 101, may also extend in the horizontal direction X.

[0039] Please refer to the following: Figure 1 and Figure 2 , Figure 2This is a schematic diagram showing the relative positions of the air knife structure 30 and the adjusting roller 50 in some embodiments of this application. In some embodiments, the position of the air outlet 301 of the air knife structure 30 relative to the adjusting roller 50 can be adjusted to adjust the air outlet direction F of the air knife structure 30 and / or the distance between the air outlet 301 of the air knife structure 30 and the adjusting roller 50. For the sake of accuracy, this application uses... Figure 1 and Figure 2 The F-axis direction is defined as the air outlet direction of the air knife structure 30. The air outlet direction F of the air knife structure 30 is the direction of concentrated airflow at the air outlet 301.

[0040] In some embodiments, the position of the air outlet 301 of the air knife structure 30 relative to the adjusting roller 50 is adjustable to adjust the air outlet direction F of the air knife structure 30. For example, the air outlet direction F of the air knife structure 30 can be set through the central axis of the adjusting roller 50, so that the airflow blown by the air knife structure 30 is concentrated on the adjusting roller 50. The supporting effect of the adjusting roller 50 reduces the vibration of the collector 101 caused by the airflow, improving the leveling uniformity of the slurry. In some embodiments, the air outlet direction F of the air knife structure 30 can also be offset from the central axis of the adjusting roller 50 to reduce the assembly difficulty of the air knife structure 30 and the adjusting roller 50.

[0041] The line connecting the air outlet 301 of the air knife structure 30 and the central axis of the adjusting roller 50 is defined as L1. In some embodiments, the air outlet direction F of the air knife structure 30 and the connecting line L1 can be arranged parallel or collinearly. The air outlet direction F of the air knife structure 30 is along a vertical direction perpendicular to the horizontal direction X.

[0042] In some embodiments, the air outlet direction F of the air knife structure 30 is deflected relative to the vertical direction, and the air outlet direction F of the air knife structure 30 is set at an angle θ with the extension direction of the connecting line L1. Thus, the downward pressure generated by the airflow of the air knife structure 30 on the collector 101 forms two components: one perpendicular and one parallel to the extension direction of the collector 101. The parallel component can improve the flowability of the slurry on the collector 101, thereby improving the slurry's fluidity, promoting slurry leveling, increasing the slurry leveling speed, and improving the slurry thickness uniformity. Exemplarily, the main body of the air knife structure 30 is inclined relative to the air outlet 301 in the horizontal direction X towards the side away from the coating module 20, so that the airflow blown out by the air knife structure 30 flows in the horizontal direction X towards the direction closer to the coating module 20. The specific angle θ can be set according to actual needs and is not specifically limited in this application.

[0043] In some embodiments, the position of the air outlet 301 of the air knife structure 30 relative to the adjusting roller 50 is adjustable to adjust the distance between the air outlet 301 and the adjusting roller 50. Thus, the coating system 100 can specifically adjust the distance between the air outlet 301 and the adjusting roller 50 according to factors such as the viscosity of the slurry and the coating thickness, thereby adjusting the downward pressure of the airflow on the slurry, and consequently adjusting the flowability of the slurry, making the slurry flow evenly and improving the thickness uniformity of the slurry. Decreasing the distance between the air outlet 301 and the adjusting roller 50 increases the downward pressure of the airflow on the slurry. Increasing the distance between the air outlet 301 and the adjusting roller 50 decreases the downward pressure of the airflow on the slurry.

[0044] In some embodiments, the position of the air outlet 301 of the air knife structure 30 relative to the adjusting roller 50 can be adjusted to adjust the air outlet direction F of the air knife structure 30 and the distance between the air outlet 301 of the air knife structure 30 and the adjusting roller 50, thereby improving the ease of control of the air knife structure 30 by the coating system 100, facilitating the adjustment of the flowability of the slurry by the coating system 100, and helping to provide coating consistency of the slurry.

[0045] The airflow rate of the air knife structure 30 can be adjusted so that the coating system 100 can set the airflow rate of the air knife structure 30 according to factors such as the fluidity of the slurry and the coating thickness. This adjusts the downward pressure generated by the airflow from the air knife structure 30 on the slurry, ensuring that the downward pressure is appropriate. This helps to level the slurry while avoiding excessive downward pressure that could cause uneven thickness in some areas.

[0046] In some embodiments, an adjustment plate may be provided at the air outlet 301 of the air knife structure 30. The tilt angle of the adjustment plate relative to the air outlet 301 can be adjusted to adjust the airflow direction of the air outlet 301.

[0047] In some embodiments, the coating system 100 further includes a conveying roller 64, which supports the current collector 101, conveys the current collector 101, and adjusts the conveying direction of the current collector 101.

[0048] The heating temperature of the first heating structure 40 is 40℃-60℃. This ensures, on the one hand, that the temperature of the slurry is within a suitable range, reducing the viscosity of high-viscosity slurries by approximately 20%-30%, improving slurry fluidity to meet coating requirements, allowing the slurry to automatically level after coating, improving coating consistency, and enhancing the uniformity of slurry thickness on the current collector 101. On the other hand, it avoids insufficient slurry fluidity due to insufficient temperature, preventing problems with coating consistency. Furthermore, it avoids excessive solvent evaporation after coating due to excessively high temperature, and also prevents energy waste in the coating system 100. The heating temperature of the first heating structure 40 can be specifically set according to actual needs; this application does not impose specific limitations. For example, the heating temperature of the first heating structure 40 can be 40℃, 41℃, 42℃, 43℃, 44℃, 45℃, 46℃, 47℃, 48℃, 49℃, 50℃, 51℃, 52℃, 53℃, 54℃, 55℃, 56℃, 57℃, 58℃, 59℃, 60℃, etc.

[0049] The first heating structure 40 is used to heat at least one of the current collector 101 located between the tank 10, the coating module 20, the air knife structure 30, the adjusting roller 50, the coating module 20, and the air knife structure 30. Exemplarily, in this embodiment, the first heating structure 40 is used to heat the tank 10 to centrally heat the slurry, reducing the difficulty of heating the slurry, improving heating efficiency, and improving the accuracy of temperature control of the slurry. The first heating structure 40 can be configured as a heating water jacket disposed on the outer wall of the tank 10, in which a heating medium is circulated. In some embodiments, the first heating structure 40 can be configured as a heating coil, which heats the tank 10 through electromagnetic induction and, in turn, heats the slurry in the tank 10. The first heating structure 40 can also be configured as other heating structures, which are not specifically limited in this application.

[0050] In some embodiments, the first heating structure 40 is used to heat the coating module 20. The coating module 20 includes a coating die 21 and a coating roller 22. The coating die 21 is connected to the tank 10. The tank 10 is used to provide slurry to the coating die 21, which is used to coat the slurry onto the current collector 101. The coating roller 22 is used to support the current collector 101 to improve the uniformity of the thickness of the slurry coated by the coating die 21. In some embodiments, the first heating structure 40 is disposed on the coating die 21 and is used to heat the coating die 21 to coat the heated slurry onto the current collector 101. In some embodiments, the first heating structure 40 is disposed on the coating roller 22 and is used to heat the coating roller 22 to heat the current collector 101, thereby heating the slurry through the current collector 101. In some embodiments, there are two first heating structures 40. One of the two first heating structures 40 is disposed on the coating die 21 and is used to heat the coating die 21. The other of the two first heating structures 40 is disposed on the coating roller 22 and is used to heat the coating roller 22.

[0051] In some embodiments, the first heating structure 40 is used to heat the regulating roller 50. After being heated, the regulating roller 50 can conduct heat to the current collector 101, raising its temperature. The heated current collector 101 then heats the slurry, thereby improving its fluidity. The first heating structure 40 can be configured as a heating channel formed within the regulating roller 50, through which a heating medium is circulated. In some embodiments, the first heating structure 40 can also be configured as a heating coil located within the regulating roller 50, used to heat the regulating roller 50 through electromagnetic induction.

[0052] In some embodiments, the first heating structure 40 is used to heat the air knife structure 30. After heating the air knife structure 30, the first heating structure 40 enables the air knife structure 30 to blow out hot air, thereby heating the slurry. In addition, the hot air can also perform preliminary drying of the slurry, thereby reducing the drying time of the slurry in the subsequent drying oven, improving drying efficiency, and increasing the production efficiency of the electrode sheets in the coating system 100.

[0053] In some embodiments, the first heating structure 40 is used to heat the current collector 101 between the coating module 20 and the air knife structure 30. The first heating structure 40 can be configured as an induction coil. When a high-frequency alternating current is passed through the induction coil, the induction coil generates an alternating magnetic field, causing the current collector 101 to generate eddy currents through electromagnetic induction. These eddy currents generate heat in the current collector 101, thereby heating the current collector 101. In some embodiments, the first heating structure 40 can also be configured as a heating element. After being heated, the temperature of the first heating structure 40 increases, and it radiates heat outward. The first heating structure 40 heats the current collector 101 through thermal radiation. In some embodiments, the first heating structure 40 can also be configured as an infrared heating structure, which heats the current collector 101 through infrared rays. The specific structural form of the first heating structure 40 can be specifically set according to actual needs, and is not specifically limited in this application.

[0054] In some embodiments, multiple first heating structures 40 may be provided, which are used to heat at least two of the current collector 101 located between the tank 10, the coating module 20, the adjusting roller 50, the air knife structure 30, and the coating module 20 and the air knife structure 30. The number of first heating structures 40 can be specifically set according to actual needs, and is not specifically limited in this application. For example, the number of first heating structures 40 can be set to one, two, three, four, etc. For example, the tank 10 and the coating module 20 are respectively provided with first heating structures 40, and two first heating structures 40 are used to heat the slurry in the tank 10 and the slurry on the coating module 20, respectively.

[0055] In some embodiments, the coating system 100 further includes an areal density detection structure 63. The areal density detection structure 63 is located downstream of the air knife structure 30 along the conveying direction of the current collector 101. The areal density detection structure 63 is used to detect the thickness of the slurry on the current collector 101 in real time, so that when an abnormality is detected, the controller can control the coating system 100 to stop working, thereby reducing waste and production losses.

[0056] Please see Figure 3 , Figure 3 This is a schematic diagram of the coating system 100 provided in some embodiments of this application. In some embodiments, the coating system 100 further includes a second heating structure 61. The second heating structure 61 is used to heat the slurry located after the air knife structure 30 along the conveying direction of the current collector 101. Thus, by heating the slurry located after the air knife structure 30 through the second heating structure 61, the fluidity of the slurry can be improved, the unevenness such as flow lines appearing on the surface of the slurry after being blown by the air knife can be reduced, the surface smoothness of the slurry can be improved, thereby improving the coating consistency of the slurry.

[0057] The second heating structure 61 can be configured as an induction coil. When a high-frequency alternating current is applied to the induction coil, the induction coil generates an alternating magnetic field, causing the current collector 101 to generate eddy currents through electromagnetic induction. These eddy currents generate heat in the current collector 101, thereby heating the current collector 101. In some embodiments, the second heating structure 61 can also be configured as a heating element. After being heated, the temperature of the second heating structure 61 increases, and it radiates heat outward. The second heating structure 61 heats the current collector 101 through thermal radiation. In some embodiments, the second heating structure 61 can also be configured as an infrared heating structure, which heats the current collector 101 through infrared rays. The specific structural form of the second heating structure 61 can be specifically set according to actual needs, and is not specifically limited in this application.

[0058] In some embodiments, the coating system 100 further includes a baffle plate 621. The baffle plate 621 is disposed between the air knife structure 30 and the coating module 20. The distance between the baffle plate 621 and the collector 101 is less than a preset value. The baffle plate 621 is used to block the airflow blown out by the air knife structure 30, preventing the airflow from blowing along the collector 101 between the coating module 20 and the air knife structure 30, thereby preventing the airflow from cooling the slurry on the collector 101, so that the slurry still has sufficient fluidity when it reaches the air knife structure 30, which in turn helps the airflow blown out by the air knife structure 30 to level the slurry and improve the thickness uniformity of the slurry.

[0059] In some embodiments, the coating system 100 further includes a negative pressure structure 622. The negative pressure structure 622 is disposed between the air knife structure 30 and the coating module 20. The negative pressure structure 622 is used to absorb the airflow blown out by the air knife structure 30 to reduce the airflow acting on the current collector 101 between the coating module 20 and the air knife structure 30, thereby preventing the airflow from cooling the slurry on the current collector 101, so that the slurry still has sufficient fluidity when it reaches the air knife structure 30, which in turn helps the airflow blown out by the air knife structure 30 to level the slurry and improve the thickness uniformity of the slurry.

[0060] In some embodiments, the coating system 100 further includes a baffle plate 621 and a negative pressure structure 622, both disposed between the air knife structure 30 and the coating module 20. In some embodiments, the negative pressure structure 622 may be disposed on the side of the baffle plate 621 near the coating module 20, so as to initially block the airflow through the baffle plate 621 and further absorb the airflow through the negative pressure structure 622, thereby further reducing the airflow acting on the current collector 101 between the coating module 20 and the air knife structure 30. In some embodiments, the negative pressure structure 622 may also be disposed on the side of the baffle plate 621 near the air knife structure 30.

[0061] Please see Figure 4, Figure 4 This is a coating experiment data table comparing electrode sheets prepared using a conventional coating system and the coating system 100 described in this application. Three sets of coating experiments were conducted on both the conventional coating system and the coating system 100 provided in this application's embodiments. Each set of coating experiments includes a comparative example (corresponding to the conventional coating system) and an example example (corresponding to the coating system 100 provided in this application's embodiments). Compared to the conventional coating system, the coating system 100 provided in this application's embodiments adds an air knife structure 30 and a first heating structure 40.

[0062] In the first group of coating experiments, the viscosity of the slurry was 18000 mPa·s, the solid content was 70%, and the designed areal density of the slurry coating was 240 g / m³. 2 The coating speed is 90 m / min. In the coating system 100 corresponding to Example 1, the included angle α is set to 50°, the heating temperature of the first heating structure 40 is set to 45°C, and the air flow rate of the air knife structure 30 is set to 50 Nm³. 3 / h, the deflection angle θ is set to 0° (that is, the air outlet direction F of the air knife structure 30 is set parallel to the connecting line L1).

[0063] In the second group of coating experiments, the viscosity of the slurry was 21000 mPa·s, the solid content was 72%, and the designed areal density of the slurry coating was 240 g / m³. 2 The coating speed is 75 m / min. In the coating system 100 corresponding to Example 2, the included angle α is set to 50°, the heating temperature of the first heating structure 40 is set to 60°C, and the air flow rate of the air knife structure 30 is set to 70 Nm³. 3 / h, with the deflection angle θ set to 0°.

[0064] In the third group of coating experiments, the viscosity of the slurry was 32,000 mPa·s, the solid content was 75%, and the designed areal density of the slurry coating was 240 g / m³. 2 The coating speed is 75 m / min. In the coating system 100 corresponding to Example 3, the included angle α is set to 70°, the heating temperature of the first heating structure 40 is set to 60°C, and the air flow rate of the air knife structure 30 is set to 80 Nm³. 3 / h, with the deflection angle θ set to 15°.

[0065] After drying the coated current collector 101, samples were taken from each electrode in each experiment. Ten sampling points were set for each electrode in this application, and the areal density at each sampling point was measured. The sampling data for each experiment are as follows:

[0066] Comparative Example 1: 218.2 g / m 2 253.8g / m 2 218.5g / m 2251.5g / m 2 217.6g / m 2 253g / m 2 226.3g / m 2 255.3g / m 2 249.6g / m 2 220.3g / m 2 ;

[0067] Example 1: 238.2 g / m 2 243.8g / m 2 238.5g / m 2 241.5g / m 2 237g / m 2 243g / m 2 236g / m 2 240g / m 2 239g / m 2 240g / m 2 ;

[0068] Comparative Example 2: 216.2 g / m 2 243.8g / m 2 249.5g / m 2 251.3g / m 2 233.2g / m 2 253.9g / m 2 223.6g / m 2 249.9g / m 2 225.3g / m 2 214.5g / m 2 ;

[0069] Example 2: 237.2 g / m 2 241.8g / m 2 239.5g / m 2 240.5g / m 2 243.2g / m 2 243.8g / m 2 236.9g / m 2 239.6g / m 2 238.3g / m 2 242.3g / m 2 ;

[0070] Comparative Example 3: 252.6 g / m 2 248.4g / m 2 235.2g / m 2 244.8g / m2 221.2g / m 2 224g / m 2 247.9g / m 2 217.6g / m 2 249.4g / m 2 222.8g / m 2 ;

[0071] Example 3: 236.2 g / m 2 244.8g / m 2 239.5g / m 2 243.5g / m 2 236.3g / m 2 243.6g / m 2 236.2g / m 2 242.3g / m 2 239.9g / m 2 242.3g / m 2 .

[0072] In slurry coating processes, the coefficient of variation (COV) is typically used to characterize the consistency of the slurry coating. The formula for calculating the COV is: COV = (standard deviation / mean) × 100%. A larger COV indicates poorer coating consistency, lower uniformity of coating thickness, and lower coating quality, which can easily lead to unstable battery performance and product defects. Conversely, a smaller COV indicates better coating consistency, higher uniformity of coating thickness, and higher coating quality, resulting in better battery performance and more stable quality. Based on the sampling data from each experiment, the COVs were calculated as follows: Comparative Example 1: 7.33%; Example 1: 1.04%; Comparative Example 2: 6.5%; Example 2: 1.01%; Comparative Example 3: 5.82%; and Example 3: 1.38%. It can be seen that, compared with traditional coating systems, when coating high-solids-content and high-viscosity slurries at high speed, the coating system 100 provided in this application embodiment can significantly reduce the coefficient of variation of the slurry after coating by setting the air knife structure 30 and the first heating structure 40, effectively improving the coating consistency of the slurry and improving the thickness uniformity of the slurry in the electrode sheet.

[0073] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A coating system (100), characterized in that, include: Tank (10), the tank (10) being used to contain slurry; A coating module (20) is connected to the tank (10) and is used to coat the slurry onto the current collector (101); An air knife structure (30) is located downstream of the coating module (20) along the conveying direction of the current collector (101) and is used to blow air onto the slurry on the current collector (101); A first heating structure (40) is used to heat the slurry located between the air knife structure (30) and the tank (10) along the conveying direction of the current collector (101).

2. The coating system (100) according to claim 1, characterized in that, The coating system (100) further includes an adjusting roller (50) located downstream of the coating module (20) along the conveying direction of the current collector (101) and close to the air knife structure (30). The adjusting roller (50) and the air knife structure (30) are located on different sides of the current collector (101). The current collector (101) located between the adjusting roller (50) and the coating module (20) is set at an angle to the horizontal direction (X).

3. The coating system (100) according to claim 2, characterized in that, The first heating structure (40) is used to heat at least one of the current collector (101) located between the tank (10), the coating module (20), the air knife structure (30), the adjusting roller (50), the coating module (20) and the air knife structure (30).

4. The coating system (100) according to claim 2, characterized in that, The angle (α) between the current collector (101) located between the adjusting roller (50) and the coating module (20) and the horizontal direction (X) is 45°-75°.

5. The coating system (100) according to claim 2, characterized in that, The distance between the adjusting roller (50) and the coating module (20) in the horizontal direction (X) is adjustable to adjust the angle (α) between the current collector (101) located between the adjusting roller (50) and the coating module (20) and the horizontal direction (X).

6. The coating system (100) according to claim 2, characterized in that, The portion of the adjusting roller (50) that is in contact with the current collector (101) forms a contact area (501), and the air outlet (301) of the air knife structure (30) is arranged opposite to the contact area (501).

7. The coating system (100) according to claim 2, characterized in that, The position of the air outlet (301) of the air knife structure (30) relative to the adjusting roller (50) can be adjusted to adjust the air outlet direction of the air knife structure (30) and / or the distance between the air outlet (301) of the air knife structure (30) and the adjusting roller (50).

8. The coating system (100) according to claim 1, characterized in that, The heating temperature of the first heating structure (40) is 40℃-60℃.

9. The coating system (100) according to claim 1, characterized in that, The coating system (100) further includes a second heating structure (61) for heating the slurry located after the air knife structure (30) along the conveying direction of the current collector (101).

10. The coating system (100) according to claim 1, characterized in that, The coating system (100) further includes a baffle plate (621), which is disposed between the air knife structure (30) and the coating module (20), and the distance between the baffle plate (621) and the current collector (101) is less than a preset value; and / or, the coating system (100) further includes a negative pressure structure (622), which is disposed between the air knife structure (30) and the coating module (20).

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