Salient point structure and dispensing plate roller

Abstract

The utility model discloses a salient point structure and a point coating plate roller, the point coating plate roller comprises a roller body and a plurality of salient points uniformly distributed on the surface of the roller body, each salient point is a salient point structure, each salient point structure comprises a bulge, and an annular groove is formed on the circumferential surface of each bulge. The grooves with the salient point structures can also bear slurry, so that liquid carrying does not depend on tension completely, and when the equipment runs at a high speed, the liquid carrying amount is increased, coating point deformation caused by inertia is reduced, the coating requirement is met, the running speed of the equipment is increased, and the productivity is improved; and the coverage rate of the point coating plate roller has a relatively wide adjusting range.

Description

Technical Field

[0001] This utility model belongs to the field of diaphragms, specifically relating to a convex structure and a dot coating roller. Background Technology

[0002] With the increasingly widespread application of new energy sources, the demand for new ion batteries is also growing daily, and the requirements for various battery characteristics are becoming increasingly stringent. For example, in the field of new energy vehicle manufacturing, the requirements for battery life, charge-discharge cycles, capacity, fast charging, and low-temperature operating environments are becoming increasingly stringent. As a crucial component of ion batteries, the requirements for the separator are also becoming increasingly stringent. The performance of the separator determines the battery's interface structure, internal resistance, and other characteristics, directly affecting the battery's capacity, cycle life, and safety performance. A high-performance separator plays a vital role in improving the overall performance of the battery. The main function of the separator is to separate the positive and negative electrodes of the battery, preventing short circuits caused by contact between the electrodes. In addition, it also allows electrolyte ions to pass through.

[0003] Currently, the most commonly used separator manufacturing processes are roll coating and spray coating. Compared to roll coating, spray coating can reduce the coating coverage, minimize the impact on separator permeability, save slurry, and improve the physical properties of the separator. However, spray coating has inherent drawbacks due to process limitations, such as uncertain spray dot shape, difficulty in thickness control, and poor coverage. Therefore, a new production process is needed that can retain the advantages of spray coating while improving its inherent defects. This new process is dot coating. Dot coating can precisely control the coating coverage, with the coating dots arranged in a matrix and approximately circular in shape. The thickness can also be precisely controlled by parameters such as the printing roller, anilox roller, and slurry, which can better meet the requirements of batteries for separators.

[0004] Dot coating is a relatively new coating method, and many aspects are still imperfect. For example, the relationship between coverage and equipment parameters is not fixed, and thickness cannot be achieved by adjusting equipment parameters. The most pressing issue is the inability to effectively control the amount of liquid carried by the printing roller. The printing roller's raised dots transfer the slurry to the roller's raised dots through contact with the anilox roller, relying on the tension difference between the slurry and the material, and then to the diaphragm. However, during debugging, insufficient liquid carry by the printing roller often results in insufficient coating dot height, leading to insufficient thickness and coating amount, failing to meet requirements. Furthermore, the deformation of the coating dots due to inertia cannot meet the demands of high-speed operation of the coating machine.

[0005] Although the invention patents with publication numbers CN 117861936 A and CN 117861935 A disclose a dot coating roller, the diaphragm coated using the dot coating rollers of CN 117861936 A and CN 117861935 A cannot overcome the problem of coating point deformation. Summary of the Invention

[0006] In order to overcome the shortcomings of the above-mentioned technical solutions, the purpose of this utility model is to provide a convex dot structure.

[0007] Another objective of this invention is to provide a dot coating roller.

[0008] The objective of this utility model is achieved through the following technical solution.

[0009] A convex structure includes: a protrusion having an annular groove formed on its circumferential surface.

[0010] In the above technical solution, the convex structure includes: a first cylinder, a frustum, a second cylinder, and a disk. The first cylinder, the frustum, the second cylinder, and the disk are coaxially arranged and connected sequentially from bottom to top. The frustum is tapered from bottom to top, and the circumferential surfaces of the frustum, the second cylinder, and the disk form an annular groove on the convex structure.

[0011] In the above technical solution, the diameter of the first cylinder is the same as the diameter of the bottom surface of the frustum, the diameter of the top surface of the frustum is the same as the diameter of the second cylinder, and the diameter of the disk is larger than the diameter of the second cylinder.

[0012] In the above technical solution, the diameter of the disk is smaller than the diameter of the first cylinder.

[0013] In the above technical solution, the height of the convex structure is 1.3-2.4 mm, the height of the frustum is 0.3-0.7 mm, the diameter of the first cylinder is 0.3-1.5 mm, the thickness of the disk is 0.05-0.45 mm, the diameter of the disk is 0.15-1.05 mm, the diameter of the second cylinder is 0.1-0.75 mm, and the height of the first cylinder is 0.5-1.5 mm.

[0014] A dot-coating roller includes: a roller body and a plurality of protrusions evenly distributed on the surface of the roller body, each of the protrusions being a protrusion structure.

[0015] In the above technical solution, the protrusions are arranged in a matrix on the surface of the roller, and the distance between every two adjacent protrusions is 450 to 2000 μm.

[0016] Compared with existing technologies, the beneficial effects are:

[0017] 1. By improving the liquid carrying capacity of the dotting roller through the shape of the bumps, the dotting roller of this utility model increases the contact surface area between the bumps and the slurry, while its grooves can also bear the slurry, so that the liquid carrying does not rely entirely on tension. When the equipment is running at high speed (≥120m / min), the liquid carrying capacity is increased while the deformation of the coating point caused by inertia is reduced, thus meeting the coating requirements, improving the equipment operating speed, and increasing the production capacity.

[0018] 2. In the dot coating process, there is a problem of insufficient liquid carrying capacity on the dot coating roller. This problem can be solved by adjusting the coverage rate, which has a wide range of adjustment.

[0019] 3. The liquid carrying capacity of the dot coating roller of this utility model is increased (characterized by coating amount), which reduces the dependence on the anilox roller (no longer depends on the anilox roller model to increase the liquid carrying capacity and adjust the coverage), reduces the cost of the anilox roller, and reduces problems such as small coating thickness, small coverage and small coating amount caused by low liquid carrying capacity.

[0020] 4. It is possible to increase the coating thickness and coating amount without increasing the coverage. Attached Figure Description

[0021] Figure 1 This is a side view of the convex point in Comparative Example 1;

[0022] Figure 2 This is a top view of the convex point in Comparative Example 1;

[0023] Figure 3 This is a side view of the convex point in Comparative Example 2;

[0024] Figure 4 This is a top view of the convex point in Comparative Example 2;

[0025] Figure 5 This is a partial schematic diagram of the dot coating roller;

[0026] Figure 6 This is a schematic diagram of the convex structure in Example 1;

[0027] Figure 7 The coating dot morphology of the diaphragm obtained by the dotting roller of Comparative Example 1 at a coating speed of 150 m / min.

[0028] Figure 8 The coating dot morphology of the diaphragm obtained by the dotting roller of Comparative Example 2 at a coating speed of 150 m / min;

[0029] Figure 9 The coating dot morphology of the diaphragm obtained by the dot coating roller of Example 1 at a coating speed of 150 m / min;

[0030] Figure 10 This is a schematic diagram of the adhesive application device.

[0031] Wherein, 1: roller body, 2: disc, 3: protrusion, 4: second cylinder, 5: truncated cone, 6: first cylinder, 7: dot coating roller, 8: base film, 9: slurry tank, 10: scraper. Detailed Implementation

[0032] The present invention will now be described in detail with reference to the accompanying drawings.

[0033] In the following examples, the base film is a PE film with a thickness of 12μm and a width of 1000mm.

[0034] In Examples 1, 1 Comparative Example, and 2 below, the density of bumps on the surface of the dot-coating roller is the same.

[0035] Electrode adhesion test: The separator and electrode were cut into samples 10cm long and 1cm wide. The separator and electrode were hot-pressed at 1200kg and 60℃ for 2s. The force of separation between the separator and the electrode was tested. Five samples were tested and the average value was calculated. The electrode is either a positive electrode or a negative electrode.

[0036] Coverage: PVDF slurry is applied to the base film using a dot-coating roller. Each dot forms a coating point on the base film. Ten coating points are selected under a microscope, and their diameters are measured. The average diameter of the ten coating points is taken, and the average area of ​​the coating points is calculated based on this average value. Then, the average area of ​​the coating points is divided by the area of ​​the square formed by connecting the centers of four coating points. The result is the coverage.

[0037] Coating thickness increment: diaphragm thickness - base film thickness.

[0038] Coating amount: weight of diaphragm per unit area - weight of base film per unit area.

[0039] The preparation method of PVDF dot coating slurry in the following examples is as follows: PVDF powder, purified water, and dispersant are mixed and stirred in a planetary mixer for 60 minutes until homogeneous (rotation speed 2000 r / min, revolution speed 40 r / min). The mixture is then milled for 15 minutes. Thickener, binder, and wetting agent are added, and the mixture is stirred in a planetary mixer for 25 minutes until homogeneous (rotation speed 1300 r / min, revolution speed 40 r / min) to obtain PVDF dot coating slurry (viscosity 300 cp). The ratio of dispersant, wetting agent, PVDF powder, purified water, thickener, and binder by mass is 0.5:2.5:16:47:16:18. The binder is styrene-butyl methacrylate, the dispersant is ammonium polyacrylate, the thickener is hydroxymethyl cellulose, and the wetting agent is polyoxyethylene ether.

[0040] Example 1

[0041] like Figures 5-6 As shown, a dot-coating roller includes: a roller body 1 and a plurality of protrusions 3 evenly distributed on the surface of the roller body 1. The protrusions 3 are arranged in a matrix on the surface of the roller body 1. The spacing between any two adjacent protrusions 3 in the transverse and longitudinal directions of the rectangular array is 1500 μm. Each protrusion 3 is a protrusion structure, wherein each protrusion structure includes: a first cylinder 6, a frustum 5, a second cylinder 4, and a disk 2. The first cylinder 6, the frustum 5, the second cylinder 4, and the disk 2 are coaxially arranged and connected sequentially from bottom to top. The frustum 5 tapers from bottom to top. The circumferential surface forms an annular groove on the convex structure. The diameter of the first cylinder 6 is the same as the diameter of the bottom surface of the frustum 5. The diameter of the top surface of the frustum 5 is the same as the diameter of the second cylinder 4. The diameter of the disk 2 is larger than the diameter of the second cylinder 4 and smaller than the diameter of the first cylinder 6. The height of the convex structure is 2mm, the height of the frustum 5 is 0.5mm, the diameter of the first cylinder 6 is 1mm, the thickness of the disk 2 is 0.2mm, the diameter of the disk 2 is 0.8mm, the diameter of the second cylinder 4 is 0.4mm, and the height of the first cylinder 6 is 1mm.

[0042] Comparative Example 1

[0043] like Figures 1-2 and Figure 5 As shown, a dot-coating roller includes: a roller body 1 and a plurality of protrusions 3 evenly distributed on the surface of the roller body 1. The spacing between every two adjacent protrusions 3 in the transverse and longitudinal directions of the rectangular array is 1500μm. Each protrusion 3 includes: a hemisphere and a cylinder. The bottom end of the cylinder is used to connect with the surface of the dot-coating roller. The hemisphere is connected to the top end of the cylinder and is integrally formed with the cylinder. The height of the protrusion 3 is 2mm, the diameter of the cylinder is 1mm, and the height of the cylinder is 1.5mm.

[0044] Comparative Example 2

[0045] like Figures 3-4 and Figure 5 As shown, a dot-coating roller includes: a roller body 1 and a plurality of protrusions 3 evenly distributed on the surface of the roller body 1. The spacing between every two adjacent protrusions 3 in the transverse and longitudinal directions of the rectangular array is 1500 μm. Each protrusion 3 is integrally formed from bottom to top as a first cylinder 6, a frustum 5, and a second cylinder 4. The first cylinder 6, the frustum 5, and the second cylinder 4 are coaxially arranged. The diameter of the first cylinder 6 is the same as the diameter of the bottom surface of the frustum 5, and the diameter of the top surface of the frustum 5 is the same as the diameter of the second cylinder 4. The diameters of the first cylinder 6 and the second cylinder 4 are 1 mm and 0.5 mm, respectively. The heights of the first cylinder 6 and the second cylinder 4 are 1.5 mm and 0.2 mm, respectively, and the height of the frustum 5 is 0.3 mm.

[0046] Example 2 and Comparative Examples 3-4

[0047] A diaphragm is obtained by coating a PVDF slurry with a viscosity of 300 cp onto a base film using a dot-coating roller (coating speed of 100 m / min). The dot-coating roller is one of Example 1 and Comparative Examples 1-2. The diaphragm of Example 2 is obtained from Example 1, and the diaphragms of Comparative Examples 3-4 are obtained sequentially from Comparative Examples 1-2. The target coating thickness is 4 μm and the coating length is 3000 m.

[0048] The coating was applied 10 times each using the dot-coating roller in Example 1, Comparative Example 1, and Comparative Example 2. The data on coating thickness increase and coating amount are shown in Table 1.

[0049] Table 1

[0050]

[0051] As can be seen from the data in Table 1, Example 2 has a larger coating thickness and coating amount compared to Comparative Examples 3 and 4, and is also more stable.

[0052] The separators obtained in Example 2 and Comparative Examples 3-4 were subjected to electrode adhesion tests in the separator characteristics (the positive electrode was aluminum foil, and the negative electrode was carbon sheet; the positive electrode was tested 5 times and the negative electrode was tested 5 times in each example / comparative example). The electrode adhesion of the separators obtained in Example 2 and Comparative Examples 3-4 was compared, as shown in Table 2 (“positive electrode” represents the adhesion between the separator and the positive electrode, and “negative electrode” represents the adhesion between the separator and the negative electrode).

[0053] Table 2

[0054]

[0055] As can be seen from the data in Table 2, compared with conventional dot-coating rollers, this invention not only increases the coating thickness and coating amount, but also increases the adhesion between the diaphragm and the electrode, which can greatly enhance the diaphragm characteristics.

[0056] Figures 1-4 These are two common types of bump shapes used in printing rollers: hemispherical bumps and trapezoidal bumps. Their liquid carrying capacity relies entirely on tension for transfer, making them highly dependent on the slurry and requiring high-quality materials for the printing roller.

[0057] Example 3 and Comparative Examples 5-6

[0058] When the slurry was coated using the dot-coating rollers of Comparative Examples 1 and 2, deformation of the coating dots occurred when the coating speed exceeded 100 m / min. To further verify this, a PVDF dot-coating slurry with a viscosity of 300 cp was coated onto the base film using a dot-coating roller at a coating speed of 150 m / min to obtain a diaphragm. The dot-coating roller was one of Example 1 and Comparative Examples 1 and 2. The coating dots of the diaphragm obtained by the dot-coating roller of Example 1 (Example 3), the diaphragm obtained by the dot-coating roller of Comparative Example 1 (Comparative Example 5), and the diaphragm obtained by the dot-coating roller of Comparative Example 2 (Comparative Example 6) were observed.

[0059] Figure 7 The image shows the morphology of the coating spots on the diaphragm obtained from the dot-coating roller of Comparative Example 1 under a microscope. Figure 8 The morphology of the coating spots on the diaphragm obtained by the dot-coating roller of Comparative Example 2 is shown under a microscope. Figure 9 The image shows the morphology of the coating spots on the diaphragm obtained from the dot-coating roller of Example 1 under a microscope. Figures 7-9 As can be seen, when coating at a speed of 150 m / min, the dot coating roller of this invention can effectively reduce the degree of deformation of the coating dots caused by inertia.

[0060] Samples were taken from the diaphragms of Examples 3, 5, and 6 above (10 test locations for each example / comparative example), and the coating thickness increase and coating amount were tested. The results are shown in the table below:

[0061] Table 3

[0062]

[0063]

[0064] As shown in Table 3, when the vehicle speed is 150 m / min, the coating thickness increment and coating amount of the diaphragm obtained by the dot coating roller of Example 1 are relatively stable, which can ensure the stability of the diaphragm during use. However, the diaphragms obtained by the dot coating roller of Comparative Example 1 and Comparative Example 2 have unstable coating thickness increments and coating amounts due to the irregularity of deformation, with large ranges, which will affect the use of the diaphragm.

[0065] Verification shows that the ability of a dot coating roller to carry the same slurry is achieved by transferring the slurry to different materials through tension. During the transfer process, while the density of the protrusions on the surface of the dot coating roller remains unchanged, the shape of the protrusions on the surface of the dot coating roller will affect the carrying capacity.

[0066] Example 4 and Comparative Examples 7-8

[0067] use Figure 10The coating apparatus shown coats a PVDF dot-coating slurry with a viscosity of 300 cp onto a base film 8 (coating speed of 100 m / min) to obtain a diaphragm. The coating apparatus includes a slurry tank 9 and a dot-coating roller 7. The base film 8 passes through a guide roller and a back roller. The slurry tank 9 contains PVDF dot-coating slurry. The dot-coating roller 7 is located below the base film 8 and is used to coat the base film 8 that has passed through the back roller. A scraper 10 is provided on one side of the dot-coating roller 7 to remove excess PVDF dot-coating slurry. The dot-coating roller 7 is mounted on a slide rail via a slider, allowing adjustment of its position on the slide rail to adjust the coverage. Specifically, when the dot-coating roller 7 is directly below the base film 8, it is considered "0 μm". Starting from "0 μm", the dot-coating roller 7 is moved five times along the slide rail in the direction of travel of the base film 8, with each movement of the dot-coating roller 7 on the slide rail covering a distance of 100 μm. After each movement, a base film of 500m length is coated to obtain a diaphragm, and the coverage of the coating points on the diaphragm is tested. The dot coating roller 7 is one of Example 1 and Comparative Examples 1-2. The diaphragm of Example 4 is obtained from Example 1, and the diaphragms of Comparative Examples 7-8 are obtained sequentially from Comparative Examples 1-2.

[0068] Table 4

[0069]

[0070]

[0071] As can be seen from Table 4, the coverage adjustment range of the dot coating roller of this invention is better than that of conventional dot coating rollers.

[0072] Example 5 and Comparative Examples 9-10

[0073] A PVDF coating slurry was applied to a base film on one side at a speed of 100 m / min using a dot-coating roller to obtain a separator. The dot-coating roller was one of those used in Example 1 and Comparative Examples 1-2. During coating, the coverage was controlled at 10%, 20%, 30%, and 40%, respectively. 500 m of slurry was coated at each of the 10%, 20%, 30%, and 40% coverage, and the coating thickness increment and coating amount of the separator were tested. The separator of Example 5 was obtained from Example 1, and the separators of Comparative Examples 9-10 were obtained sequentially from Comparative Examples 1-2.

[0074] Table 5

[0075]

[0076] As can be seen from Table 5, without increasing the coverage, compared with the comparative dot-coating roller, this invention can increase the height of the coating point (increase the coating thickness) and increase the coating amount.

[0077] The present invention has been described above by way of example. It should be noted that, without departing from the core of the present invention, any simple modifications, alterations or other equivalent substitutions that can be made by those skilled in the art without creative effort fall within the protection scope of the present invention.

Claims

1. A convex dot structure, characterized in that, include: The protrusion has an annular groove formed on its circumferential surface. The protrusion structure includes a first cylinder (6), a frustum (5), a second cylinder (4), and a disk (2). The first cylinder (6), the frustum (5), the second cylinder (4), and the disk (2) are coaxially arranged and connected sequentially from bottom to top. The frustum (5) is tapered from bottom to top. The circumferential surfaces of the frustum (5), the second cylinder (4), and the disk (2) form an annular groove on the protrusion structure.

2. The convex structure according to claim 1, characterized in that, The diameter of the first cylinder (6) is the same as the diameter of the bottom surface of the frustum (5), the diameter of the top surface of the frustum (5) is the same as the diameter of the second cylinder (4), and the diameter of the disk (2) is greater than the diameter of the second cylinder (4).

3. The convex structure according to claim 1, characterized in that, The diameter of the disk (2) is smaller than the diameter of the first cylinder (6).

4. A dot-coating roller, characterized in that, include: The roller body (1) and a plurality of protrusions (3) evenly distributed on the surface of the roller body (1), each of the protrusions (3) being the protrusion structure described in any one of claims 1 to 3.

5. The dotting roller according to claim 4, characterized in that, The protrusions (3) are arranged in a matrix on the surface of the roller (1), and the distance between every two adjacent protrusions (3) is 450~2000μm.

Images