Current collector coating equipment

Abstract

The utility model discloses current collector coating equipment which comprises a drop roller, a plate roller and a press roller, the press roller is arranged at the top of the plate roller, the drop roller is arranged below the plate roller, and the lower part of the drop roller is arranged in a trough; the plate roller and the drop roller can rotate along respective axes respectively, a material carrying gap is formed between the drop roller and the plate roller, and the pressing roller is used for pressing a to-be-coated foil to be in contact with the surface of the plate roller; a mesh-shaped concave-convex structure is arranged on the surface of the drop roller, and the distribution range of the mesh-shaped concave-convex structure on the surface of the drop roller is equal to or larger than the material carrying face, carrying out material carrying on the printing roller, of the drop roller. The drop roller is connected with a position adjusting mechanism used for adjusting the size of a strip gap between the drop roller and the printing roller. According to the utility model, the problems of missed coating defect, bubble interference and the like in the existing strip coating mode can be solved.

Description

Technical Field

[0001] This utility model relates to the field of current collector technology, specifically to a current collector coating device. Background Technology

[0002] In the existing technology, the performance and quality of conductive current collectors play an important role in the adhesion of active materials and the microcurrent in the enrichment system. The lithium battery industry usually coats the surface of the current collector with a carbon coating layer to enhance its various performance aspects. In the existing technology, the coating process is prone to defects such as missed coating due to slurry bubbles and non-dense rollers.

[0003] The current coating method is roller printing transfer coating, among which the commonly used coating material carrying methods are: Method 1, by directly immersing the printing roller in the material tank and the paste to achieve material carrying; Method 2, by using a traditional rubber inking roller device to transfer and conduct material carrying, that is, immersing the inking roller in the material tank to carry material, and then transferring the material to the printing roller through the inking roller.

[0004] Existing material feeding methods and processes have the following defects and shortcomings: In Method 1, the printing roller is directly immersed in the material tank and rotates, which causes a high frequency of slurry agitation and easily generates air bubbles, resulting in coating defects such as missed coatings on the printing plate. In Method 2, due to the smooth surface of the ink delivery roller, problems such as insufficient material feeding and uneven material feeding are likely to occur, resulting in air bubbles or missed coatings. Regardless of Method 1 or Method 2, a pressure roller is required to press the aluminum foil into contact with the printing roller for coating. However, the high hardness of the pressure roller will affect the density of the contact with the printing roller. The hardness of the commonly used pressure roller will result in insufficient density between the aluminum foil and the printing roller, which will easily produce small missed coating points. Utility Model Content

[0005] The purpose of this invention is to provide a current collector coating device that solves problems such as missed coating and bubble interference in existing coating methods.

[0006] To achieve the above objectives, the technical solution provided by this utility model is as follows:

[0007] A current collector coating device includes an ink delivery roller, a printing roller, and a pressure roller. The pressure roller is provided on the top of the printing roller, and the ink delivery roller is provided below the printing roller. The lower part of the ink delivery roller is placed in a material trough.

[0008] The printing roller and the ink delivery roller are each able to rotate along their respective axes. There is a material gap between the ink delivery roller and the printing roller. The pressure roller is used to press the foil to be coated until it contacts the surface of the printing roller.

[0009] The surface of the ink delivery roller is provided with a mesh-shaped uneven structure, and the distribution range of the mesh-shaped uneven structure on the surface of the ink delivery roller is equal to or greater than the material-carrying surface of the ink delivery roller that carries the material onto the printing roller.

[0010] The ink delivery roller is connected to a position adjustment mechanism for adjusting the material gap between the ink delivery roller and the printing roller.

[0011] The mesh-shaped concave-convex structure is an engraved structure formed on the surface of the ink roller.

[0012] To optimize the above technical solution, the specific measures also include:

[0013] The surface of the ink roller has a uniformly arranged mesh-shaped concave-convex structure, wherein the cross-section of a single mesh-shaped concave-convex structure is polygonal.

[0014] Preferably, the depth of the mesh-shaped concave-convex structure is 25~30μm.

[0015] The material gap is the distance between the bottom surface of the mesh-shaped uneven structure on the surface of the ink roller and the bottom surface of the printing plate at the point where the ink roller and the printing plate are closest. This distance is 1000~1200μm.

[0016] Preferably, the hardness of the pressure roller is 60~65 SHA°.

[0017] The position adjustment mechanism includes a control motor and a support member that connects the control motor to the ink delivery roller. The support member can drive the ink delivery roller to move its position under the action of the control motor.

[0018] The ink delivery roller is located directly below or diagonally below the printing roller.

[0019] Furthermore, the ink delivery roller is connected to a variable frequency motor, which is used to adjust the rotational speed of the ink delivery roller along its axis.

[0020] Furthermore, the printing roller is mounted on a coating machine, which has one or two drying ovens for drying the front and back coatings respectively. Each drying oven has at least three sections with independently set temperatures.

[0021] Compared with the prior art, the beneficial effects of this utility model are:

[0022] The current collector coating equipment of this invention can adjust the material gap between the ink delivery roller and the printing roller to a suitable range through the position adjustment mechanism, so that the foam in the slurry is more easily squeezed and broken during material feeding, thereby achieving a good defoaming effect.

[0023] The current collector coating equipment of this invention also achieves the effect of increasing the amount of material carried and removing air bubbles by using an ink roller with a mesh-like uneven structure on its surface.

[0024] The current collector coating equipment of this utility model achieves the purpose of removing small foil leakage points by limiting the hardness of the pressure roller used, so that when the pressure roller presses down on the foil to be coated and makes close contact with the printing roller.

[0025] In addition, the current collector coating equipment of this utility model is equipped with a variable frequency motor for the ink delivery roller, which can adjust the speed of the ink delivery roller through the variable frequency motor and increase the uniformity of the material carried by the ink delivery roller. Attached Figure Description

[0026] Figure 1 : A schematic diagram of the current collector coating equipment of this utility model.

[0027] Figure 2 : A schematic diagram of the mesh-shaped concave-convex structure on the surface of the ink roller of this utility model.

[0028] In the diagram: 1-pressure roller, 2-printing roller, 3-inking roller, 4-mesh-shaped concave-convex structure, 5-material trough, 6-foil to be coated. Detailed Implementation

[0029] The present invention will be further described in detail below through embodiments, but it should not be construed as the scope of the present invention being limited to the following embodiments. All technologies implemented based on the present invention fall within the scope of the present invention.

[0030] This utility model provides a current collector coating device, such as... Figure 1 As shown, it includes an ink delivery roller 3, a printing roller 2, and a pressure roller 1. The printing roller 2 is located above the ink delivery roller 3, and the lower part of the ink delivery roller 3 is placed in the material trough 5. The top of the printing roller 2 is provided with a pressure roller 1. The printing roller 2 and the ink delivery roller 3 can rotate along their respective axes. There is a material gap between the ink delivery roller 3 and the printing roller 2. The pressure roller 1 is used to press the foil material 6 to be coated until it contacts the surface of the printing roller 2.

[0031] The inking roller 3 is connected to a position adjustment mechanism for adjusting the gap between the inking roller 3 and the printing roller 2. This invention can adjust the gap between the inking roller 3 and the printing roller 2 to a suitable range, thereby squeezing and breaking the foam in the slurry during material feeding, achieving a good defoaming effect.

[0032] like Figure 2 As shown, the surface of the ink roller 3 is provided with a mesh-shaped concave-convex structure 4. The distribution range of the mesh-shaped concave-convex structure 4 on the surface of the ink roller 3 is greater than or equal to the material-carrying surface on the ink roller 3 used for carrying material onto the printing roller 2.

[0033] The mesh-shaped concave-convex structure 4 in this utility model can be formed on the surface of the ink roller 3 by engraving.

[0034] In this invention, the mesh-shaped convex and concave structures 4 are evenly arranged on the surface of the ink roller 3. The cross-section of each individual mesh-shaped convex and concave structure 4 is polygonal, and can be selected as a quadrilateral, triangular, pentagonal, hexagonal, or other cross-sectional shapes. Figure 2As shown in the example.

[0035] The depth of the mesh-shaped uneven structure 4 has a significant impact on the removal of foam in the slurry during material handling. By using a mesh-shaped uneven structure 4 with an appropriate depth, air bubbles can be removed more effectively. In this invention, the depth of the mesh-shaped uneven structure 4 is preferably 25~30μm, as detailed in the following examples and experiments.

[0036] This invention utilizes a pressure roller 1 with a suitable hardness range, enabling the pressure roller 1 to remove small foil leakage points when pressing down on the aluminum foil and making close contact with the printing roller 2. In this invention, the hardness of the pressure roller 1 is preferably 60~65 SHA°, as detailed in the following examples and experiments.

[0037] In this invention, the ink delivery roller 3 is also connected to a variable frequency motor, which can adjust the rotation speed of the ink delivery roller 3 along its axis. In this invention, the rotation of the ink delivery roller 3 along its axis is preferably uniform and the rotation speed is maintained at 75-85 rpm.

[0038] The printing roller 2 in this invention can be a conventional gravure roller, such as a gravure roller with a mesh count of 200-230 mesh and a gravure depth of 32-36 μm; the printing roller 2 is installed on a coating machine, and the rotation speed of the printing roller 2 is adjusted and set by the coating machine.

[0039] Furthermore, the coating machine is equipped with one or two drying ovens, which are used for drying the front and back coatings respectively. Each drying oven has at least three sections with independently set temperatures.

[0040] The current collector coating equipment of this utility model is used as follows:

[0041] Step 1: Place the slurry in the trough 5, ensuring that the height of the slurry in the trough 5 is sufficient for the lower part of the ink roller 3 to contact the slurry;

[0042] Step 2: Start the motor used to stir the slurry in the mixing tank 5, and stir to make the slurry evenly distributed;

[0043] Step 3: Adjust the position of the inking roller 3 so that the slurry on the surface of the inking roller 3 can be transferred to the printing roller 2, and control the distance between the inking roller 3 and the printing roller 2 to a suitable size so that the air bubbles in the slurry can be squeezed and broken when passing through the material gap between the inking roller 3 and the printing roller 2; adjust the rotation speed of the inking roller 3 to make it carry the material evenly.

[0044] Step 4: Adjust the coating speed of the coating machine where the printing roller 2 is located, and press down the pressure roller 1 to press the foil material 6 to be coated until it contacts the printing roller 2, so that the slurry on the printing roller 2 is coated onto the surface of the foil material.

[0045] Step 5: The coated foil is dried in the oven of the coating machine and then wound up;

[0046] Step Six: Conduct physical property tests on the finished carbon-coated foil. The test methods include:

[0047] (1) Coating surface density: determined by weighing method;

[0048] (2) Penetration resistance: A penetration resistance tester was used;

[0049] (3) Coating peel force: using a tensile testing machine.

[0050] The present invention will be further described in detail below with reference to specific embodiments and experiments. The following specific embodiments all adopt the above-described method of using the current collector coating equipment:

[0051] Example 1

[0052] The surface of the ink delivery roller 3 is engraved with a mesh-like convex-concave structure 4; in this embodiment, the engraving depth of the ink delivery roller 3 surface is 25μm, and the cross-section of a single mesh-like convex-concave structure 4 is quadrilateral; the rotation speed of the ink delivery roller 3 is 80 rpm, and the width of the coated aluminum foil is 300mm; the engraving width of the gravure roller 2 is 250mm, the mesh size is 220, the depth is 34μm, and the tension is suitable; the material gap is 1mm; the solid content of the carbon coating slurry is 10%, the coating length is 100m, and the coating speed of the coating machine is 80m / min; the hardness of the pressure roller 1 is 65. SHA°; The coating machine is equipped with one and two drying ovens (the first drying oven is set after the front coating, and the second drying oven is set after the back coating). Each drying oven has at least three sections to ensure that the coating slurry is baked. After the front coating of the carbon-coated aluminum foil is completed, it enters the first drying oven. After passing through the first, second, and third sections of the first drying oven, it exits the oven for back coating. After the back coating is completed, it enters the second drying oven. After passing through the first, second, and third sections of the second drying oven, it exits the oven for winding. The temperatures of the first, second, and third sections of the first and second drying ovens are 80℃, 90℃, and 90℃, respectively.

[0053] Example 2

[0054] The surface engraving depth of the ink roller 3 is 30μm, and the other conditions are the same as in Example 1.

[0055] Example 3

[0056] The surface engraving depth of the ink roller 3 is 35μm, and the other conditions are the same as in Example 1.

[0057] Example 4

[0058] The surface engraving depth of the ink roller 3 is 40μm, and the other conditions are the same as in Example 1.

[0059] Comparative Example 1

[0060] The surface of the ink roller 3 is unengraved, and the other conditions are the same as in Example 1.

[0061] Comparative Example 2

[0062] Without using the ink delivery roller 3, the gravure roller 2 is directly immersed in the slurry, and the other conditions are the same as in Example 1.

[0063] Comparative Example 3

[0064] The pressure roller 1 has a hardness of 80 SHA°, and the other conditions are the same as in Example 1.

[0065] Comparative Example 4

[0066] The pressure roller 1 has a hardness of 75 SHA°, and the other conditions are the same as in Example 1.

[0067] Comparative Example 5

[0068] The pressure roller 1 has a hardness of 70 SHA°, and the other conditions are the same as in Example 1.

[0069] Comparative Example 6

[0070] The pressure roller 1 has a hardness of 60 SHA°, and the other conditions are the same as in Example 1.

[0071] Comparative Example 7

[0072] The hardness of roller 1 is 55 SHA°, and the other conditions are the same as in Example 1.

[0073] Comparative Example 8

[0074] The pressure roller 1 has a hardness of 50 SHA°, and the other conditions are the same as in Example 1.

[0075] For each of the above embodiments and comparative examples, two meters of carbon-coated aluminum foil samples were randomly selected for testing. The test results are shown in Table 1.

[0076] Table 1. Detection results of the examples and comparative samples

[0077]

[0078] The aluminum foil samples of each embodiment and comparative example were subjected to performance tests, and the results are shown in Table 2:

[0079] Table 2 Performance test results of the examples and comparative samples

[0080]

[0081] The comparison between the examples and Comparative Example 2 shows that using the ink roller 3 can effectively improve the problems of bubbles and poor coating compared to not using the ink roller 3. The comparison between the examples and Comparative Example 1 shows that the ink roller 3 with a mesh-shaped uneven structure 4 formed on its surface by engraving can remove bubbles and poor coating more effectively than the ordinary ink roller 3.

[0082] Comparative studies of Examples 1-4 revealed that when the engraving depth of the ink delivery roller 3 is 25-30 μm, its function of transferring slurry is stable and its effect of removing air bubbles is obvious; when the engraving depth of the ink delivery roller 3 is 35 or 40 μm, the transfer of slurry is unstable, resulting in large-area missed coating; considering that the deeper the engraving depth of the ink delivery roller 3, the higher the cost, the ink delivery roller 3 with an engraving depth of 25 μm can be preferred.

[0083] Comparative studies of Examples 1 and 3-8 revealed that the hardness of the pressure roller 1 has a significant impact on small foil leakage points: excessive hardness of the pressure roller 1 results in a greater number of small foil leakage points in the coating; these leakage points significantly reduce the areal density and coating peel strength, affecting the performance of the carbon-coated aluminum foil; lower hardness of the pressure roller 1 can significantly improve the situation of small foil leakage, but excessively low hardness of the pressure roller 1 can cause severe wrinkling during the foil coating process, affecting production; after multiple experiments, it was found that a hardness of 60-65 for the pressure roller 1 is most suitable for production, resulting in superior product performance; considering the manufacturing cost of the pressure roller 1, the lower the hardness, the higher the manufacturing cost, so a pressure roller 1 with a hardness of 65 degrees can be preferred.

[0084] The performance test results in Table 2 show that the performance of the products produced by the equipment of this utility model can meet the requirements of production and use.

[0085] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Any simple modifications, equivalent substitutions, and improvements made by those skilled in the art to the above embodiments without departing from the scope of the present utility model's technical solution and based on the technical essence of the present utility model shall still fall within the protection scope of the present utility model's technical solution.

Claims

1. A current collector coating device, comprising an ink delivery roller, a printing roller, and a pressure roller, characterized in that: The top of the printing roller is provided with a pressure roller, and the bottom of the printing roller is provided with an ink delivery roller, the lower part of which is placed in the material trough; The printing roller and the ink delivery roller are each able to rotate along their respective axes. There is a material gap between the ink delivery roller and the printing roller. The pressure roller is used to press the foil to be coated until it contacts the surface of the printing roller. The surface of the ink delivery roller is provided with a mesh-shaped uneven structure, and the distribution range of the mesh-shaped uneven structure on the surface of the ink delivery roller is equal to or greater than the material-carrying surface of the ink delivery roller that carries the material onto the printing roller. The ink delivery roller is connected to a position adjustment mechanism for adjusting the material gap between the ink delivery roller and the printing roller.

2. The current collector coating equipment according to claim 1, characterized in that: The mesh-shaped concave-convex structure is an engraved structure formed on the surface of the ink roller.

3. The current collector coating equipment according to claim 1, characterized in that: The surface of the ink roller has a uniformly arranged mesh-shaped concave-convex structure, wherein the cross-section of a single mesh-shaped concave-convex structure is polygonal.

4. The current collector coating equipment according to claim 1, characterized in that: The depth of the mesh-shaped concave-convex structure is 25–30 μm.

5. The current collector coating equipment according to claim 1, characterized in that: The material gap is the distance between the bottom surface of the mesh-shaped uneven structure on the surface of the ink roller and the bottom surface of the printing plate at the point where the ink roller and the printing plate are closest. This distance is 1000-1200μm.

6. The current collector coating equipment according to claim 1, characterized in that: The hardness of the pressure roller is 60-65 SHA°.

7. The current collector coating equipment according to claim 1, characterized in that: The position adjustment mechanism includes a control motor and a support member that connects the control motor to the ink delivery roller. The support member can drive the ink delivery roller to move its position under the action of the control motor.

8. The current collector coating equipment according to claim 1, characterized in that: The ink delivery roller is located directly below or diagonally below the printing roller.

9. The current collector coating equipment according to claim 1, characterized in that: The ink delivery roller is connected to a variable frequency motor, which is used to adjust the rotation speed of the ink delivery roller along its axis.

10. The current collector coating equipment according to claim 1, characterized in that: The printing roller is mounted on a coating machine, which has one or two drying ovens for drying the front and back coatings respectively. Each drying oven has at least three sections with independently set temperatures.

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