A micro-pit coating mechanism, diaphragm coating apparatus and method

Abstract

The application discloses a kind of micro concave coating mechanisms, including micro concave roller, close roller, first material box and second material box, the first material box is filled with micron organic adhesive slurry, the second material box is filled with nanometer inorganic oxide slurry, the circumferential wall of the micro concave roller is staggered and is provided with several micrometer first pits and nanometer second pits, the circumferential wall portion of the micro concave roller extends to the first material box and second material box, the close roller is used to support diaphragm, and diaphragm is driven and is in contact or separated from micro concave roller, when the micro concave roller rotates, slurry in first pit and second pit is coated on substrate or pole piece.The application also discloses diaphragm coating equipment and method using the micro concave coating mechanism, so that inorganic oxide slurry and organic adhesive slurry can be uniformly coated on substrate or pole piece using one micro concave roller, coating process is simpler, can improve work efficiency, while reducing equipment cost.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to a micro-grooving coating mechanism, diaphragm coating equipment and method. Background Technology

[0002] Current lithium battery separator preparation equipment requires first applying nano-sized alumina slurry to the separator equipment, and then coating it with binder slurry. The alumina slurry plays a role in adjusting the separator porosity and improving safety, while the binder slurry can bond the electrode and the separator. Both are indispensable in the current battery production process.

[0003] Currently, two different mechanisms (a microgravure coating mechanism and a rotary spraying mechanism) are required to coat two different slurries onto a base film. For example, CN116190920B discloses a coated diaphragm, its preparation method, and its application. This invention describes coating a heat-resistant layer slurry onto the surface of the base film using microgravure roller coating technology before spraying the adhesive layer slurry onto the base film. Another example is CN207086206U, which discloses a coating machine production line combining microgravure and spraying, including an unwinding assembly, a microgravure coating assembly, an oven assembly, a process traction assembly, a rewind traction assembly, a rewinding assembly, a first spraying mechanism, and a second spraying mechanism arranged sequentially. The microgravure coating assembly includes the microgravure coating mechanism. However, using two different mechanisms in one process device increases equipment costs, raises coating production costs, and also makes the process more complex. Summary of the Invention

[0004] The present invention aims to provide a micro-grooving mechanism, diaphragm coating equipment and method to solve the problem of high cost of diaphragm coating equipment in the prior art.

[0005] The technical solution adopted by this invention to solve its technical problem is:

[0006] A microgravure coating mechanism includes a microgravure roller, a proximity roller, and a material box. The material box is used to hold organic adhesive slurry with a particle size of micrometers and inorganic oxide slurry with a particle size of nanometers. A plurality of first and second recesses are alternately arranged on the peripheral wall of the microgravure roller. The opening and depth of the first recesses are in the micrometer range, and the opening and depth of the second recesses are in the nanometer range. When the microgravure roller rotates, its peripheral wall passes through the material box, and the organic adhesive slurry and inorganic oxide slurry in the material box enter the first and second recesses respectively. The proximity roller is used to support the diaphragm and drive the diaphragm to abut or separate from the microgravure roller. When the microgravure roller rotates, the organic adhesive slurry in the first recess and the inorganic oxide slurry in the second recess are simultaneously coated onto the diaphragm.

[0007] As a further improvement to the above technical solution, the material box includes a first material box and a second material box, which are arranged sequentially along the rotation direction of the microgravure roller. The first material box is used to hold organic adhesive slurry with a particle size of micrometers, and the second material box is used to hold inorganic oxide slurry with a particle size of nanometers.

[0008] As a further improvement to the above technical solution, both the first material box and the second material box are provided with scrapers. The scrapers scrape off excess organic adhesive slurry on the microgravure roller back to the first material box, and scrape off excess inorganic oxide slurry on the microgravure roller back to the second material box.

[0009] As a further improvement to the above technical solution, the first and second recesses are in the shape of one or more of the following: circular, polygonal, pentagonal, BT dot and FM dot.

[0010] The technical solution also provided by this invention is:

[0011] A diaphragm coating apparatus, including the microgravure coating mechanism.

[0012] This invention also provides:

[0013] A diaphragm coating method involves simultaneously coating an inorganic oxide particle and an organic binder slurry onto a diaphragm using a microgravure roller. The organic binder slurry and the inorganic oxide slurry use the same solvent. The organic binder slurry and the inorganic oxide slurry are stored in a first pit and a second pit on the microgravure roller, respectively. The size of the first pit is on the micrometer scale, and the size of the second pit is on the nanometer scale. The first pit and the second pit are arranged alternately.

[0014] As a further improvement to the above technical solution, the inorganic oxide slurry is formed by mixing inorganic oxide particles with an oily solvent, and the organic adhesive slurry is formed by mixing organic adhesive particles with an oily solvent.

[0015] As a further improvement to the above technical solution, the organic adhesive particles include one or more of polyvinyl alcohol, carboxymethyl cellulose, or polyvinylidene fluoride; the inorganic oxide particles include one or more of alumina ceramic particles, lithium steel titanium oxide particles, lithium steel zirconium oxide, or fast ion conductors.

[0016] As a further improvement to the above technical solution, the organic adhesive particles are polyvinylidene fluoride adhesive particles.

[0017] As a further improvement to the above technical solution, the inorganic oxide particles are alumina ceramic particles, which include at least alumina, and also include one or more of silicon dioxide, magnesium oxide or calcium oxide.

[0018] The beneficial effects of this invention are: inorganic oxide slurry and organic adhesive slurry can be uniformly coated on the diaphragm using a single micro-gravure roller, making the coating process simpler, improving work efficiency, and reducing equipment costs, which in turn reduces production costs. Attached Figure Description

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0020] Figure 1 This is a schematic diagram of a micro-coating mechanism according to an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the structure of a micro-gravure coating mechanism in an embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of coating the slurry onto the diaphragm in an embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of the structure of a diaphragm coating device according to an embodiment of the present invention;

[0024] Figure 5 yes Figure 4 A magnified view of a portion of point A in the middle.

[0025] Reference numerals in the attached drawings: 1. Microgravure roller; 101. First recess; 102. Second recess; 2. First material box; 3. Second material box; 4. Approach roller; 5. Diaphragm; 6. Equipment wall panel; 7. Approach roller fine-tuning mechanism; 8. Approach roller distance adjustment mechanism; 9. Microgravure roller fine-tuning mechanism; 10. Microgravure roller distance adjustment mechanism; 11. First scraper; 12. Second scraper; 13. Third scraper; 14. Scraper adjustment mechanism. Detailed Implementation

[0026] The following will clearly and completely describe the concept, specific structure, and technical effects of the present invention in conjunction with embodiments and accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention. Furthermore, all connections / linkages involved in the patent do not simply refer to direct connection of components, but rather to the ability to form a better connection structure by adding or reducing connecting accessories according to specific implementation conditions. For example, fixed connections / installations can use accessories such as screws and bolts, or can be directly connected by welding, bonding, etc. The various technical features in this invention can be combined interactively without contradicting each other.

[0027] Reference Figure 1and Figure 2 An embodiment of the present invention discloses a microgravure coating mechanism, including a microgravure roller 1, a proximity roller 4, and a material box. A plurality of first pits 101 and second pits 102 are alternately arranged on the peripheral wall of the microgravure roller 1. The opening and depth of the first pits 101 are at the micrometer level, and the opening and depth of the second pits 102 are at the nanometer level. In this embodiment, after the peripheral wall of the microgravure roller 1 is unfolded, the first pits 101 and second pits 102 are arranged in a rectangular array. One of the second pits 102 not on the edge is located at the geometric center of the four surrounding first pits 101. Similarly, a first pit 101 not on the edge is also located at the geometric center of the four surrounding second pits 102. This ensures that the slurry in the first pits 101 and second pits 102 is coated more evenly on the diaphragm 5, improving the coating quality. In other embodiments, the first pits 101 and second pits 102 can be designed with a honeycomb or other structural features. Furthermore, the shapes of the first recess 101 and the second recess 102 can be regular shapes, such as circles, polygons, pentagons, etc., as shown in the reference. Figure 2 In this embodiment, a rhombus shape is used in polygons, and the angle of the rhombus is selected between 30° and 60°, preferably 30°, 38°, 45° or 60°; the shapes of the first recess 101 and the second recess 102 can also be irregular shapes, such as BT dots and FM dots, or a combination of BT dots and FM dots.

[0028] Specifically, there are two material boxes, labeled as material box 2 and material box 3 respectively. Material box 2 and material box 3 are arranged sequentially along the rotation direction of the microgravure roller 1. Material box 2 contains micron-sized organic adhesive slurry (preferably PVDF adhesive slurry), and material box 3 contains nano-sized inorganic oxide slurry (preferably alumina ceramic particle slurry). Part of the peripheral wall of the microgravure roller 1 extends into the first material box 2 and the second material box 3 respectively. Thus, when the microgravure roller 1 rotates, the peripheral wall of the microgravure roller 1 first enters the first material box 2. The organic binder slurry in the first material box 2 enters the first pit 101. Specifically, since the size of the first pit 101 and the particle size of the organic binder slurry are both in the micrometer range, the binder particles in the organic binder slurry enter the first pit 101. (The binder particles are binder microspheres. It is well known that battery binders are microsphere binders. Binder microspheres are objectively existing binders in the potassium battery field, such as SBR microsphere binders, etc., which will not be described in detail here.) The binder particles do not enter the nano-sized second pit 102 and will not easily fall off under the action of tension. Then, the peripheral wall of the micro-gravure roller 1 enters the second material box 3, and the nano-sized inorganic oxide slurry in the second material box 3 enters the second recess 102. Specifically, since the alumina ceramic particles in the inorganic oxide slurry and the second recess 102 are both nano-sized, the alumina ceramic particles will not easily fall off under the action of tension when they enter the second recess 102. In this way, the inorganic oxide slurry and the organic adhesive slurry are respectively filled into the first recess 101 and the second recess 102.

[0029] Furthermore, the proximity roller 4 is used to support the diaphragm 5 and drive the diaphragm 5 to abut or separate from the microgravure roller 1. When the diaphragm 5 abuts against the microgravure roller 1, the microgravure roller 1 rotates and simultaneously coats the mechanical adhesive slurry in the first pit 101 and the inorganic oxide slurry in the second pit 102 onto the diaphragm 5, thereby completing the coating work of the diaphragm 5.

[0030] In a more preferred embodiment, as the microgravure roller 1 rotates, its peripheral wall passes sequentially through the first material box 2 and the second material box 3. Both the first material box 2 and the second material box 3 are equipped with scrapers, which scrape excess paste from the microgravure roller 1 back into the first material box 2 and the second material box 3. Specifically, refer to... Figure 5The scraper includes a first scraper 11 and a second scraper 12 disposed at both ends of the first material box 2 along the rotation direction of the microgravure roller 1, and a third scraper 13 disposed at the rear end of the second material box 3. After the microgravure roller 1 takes the organic adhesive slurry from the first material box 2, the second scraper 12 scrapes off the excess organic adhesive slurry on the peripheral wall of the microgravure roller 1, so that only the first pit 101 on the microgravure roller 1 contains organic adhesive slurry. In addition, when the microgravure roller 1 passes through the second material box 3, the third scraper 13 scrapes off the inorganic oxide slurry on the peripheral wall of the microgravure roller 1, so that only the second pit 102 on the microgravure roller 1 contains inorganic oxide slurry. This makes the peripheral wall of the microgravure roller 1 smooth, which facilitates more uniform coating of organic adhesive slurry and inorganic oxide slurry onto the diaphragm 5.

[0031] Reference Figure 4 The embodiments of the present invention also disclose a diaphragm coating device, including the microgravure coating mechanism, and further including a device wall plate 6 and a proximity roller fine-tuning mechanism 7, a proximity roller distance adjustment mechanism 8, a microgravure roller fine-tuning mechanism 9, a microgravure roller distance adjustment mechanism 10 and a scraper adjustment mechanism 14 installed on the device wall plate 6; the microgravure roller 1, the proximity roller 4, the first material box 2 and the second material box 3 in the microgravure coating mechanism are also installed on the device wall plate 6.

[0032] Furthermore, the proximity roller distance adjustment mechanism 8 is used to drive the proximity roller 4 to move towards the microgravure roller 1, thereby causing the diaphragm 5 to approach or move away from the microgravure roller 1. The proximity roller fine-tuning mechanism 7 is used to fine-tune the position of the proximity roller 4 when the diaphragm 5 abuts against the microgravure roller 1, so as to control the contact pressure between the diaphragm 5 and the microgravure roller 1. Similarly, the microgravure roller distance adjustment mechanism 10 is used to drive the microgravure roller 1 to move towards the proximity roller 4, thereby causing the microgravure roller 1 to approach or move away from the diaphragm 5. The microgravure roller fine-tuning mechanism 9 is used to fine-tune the position of the microgravure roller 1 when the diaphragm 5 abuts against the microgravure roller 1, so as to control the contact pressure between the diaphragm 5 and the microgravure roller 1. The doctor blade adjustment mechanism 14 can adjust the distance between the first doctor blade 11, the second doctor blade 12, and the third doctor blade 13 and the proximity roller 4, thereby improving the doctor blade's effect on removing the slurry on the microgravure roller 1. In this embodiment, both the proximity roller distance adjustment mechanism 8 and the microgravure roller distance adjustment mechanism 10 are driven by cylinders, while both the proximity roller fine-tuning mechanism 7 and the microgravure roller fine-tuning mechanism 9 are driven by linear motors. The doctor blade adjustment mechanism 14 is driven by a combination of cylinders and linkage mechanisms. The specific structures of the proximity roller fine-tuning mechanism 7, the proximity roller distance adjustment mechanism 8, the microgravure roller fine-tuning mechanism 9, the microgravure roller distance adjustment mechanism 10, and the doctor blade adjustment mechanism 14 are conventional techniques in the field and will not be described in detail here.

[0033] An embodiment of the present invention also discloses a diaphragm coating method, in which an inorganic oxide slurry and an organic adhesive slurry are simultaneously coated onto a diaphragm 5 using a microgravure roller 1. The organic adhesive slurry and the inorganic oxide slurry are stored respectively in first recesses 101 and second recesses 102 alternately arranged on the microgravure roller 1. After coating, the organic adhesive slurry and the inorganic oxide slurry in the first recesses 101 and second recesses 102 are alternately distributed on the diaphragm 5. (See specific details for details.) Figure 3 .

[0034] The specific steps for the micro-gravure roller 1 to simultaneously coat the inorganic oxide slurry and organic binder slurry onto the diaphragm 5 are as follows:

[0035] 1. When the microgravure roller 1 rotates, its peripheral wall first enters the first material box 2. The adhesive microspheres (microstructure of organic adhesive slurry) in the first material box 2 enter the first pit 101 on the microgravure roller 1. Since both the adhesive microspheres and the first pit 101 are micron-sized, the adhesive microspheres will not fall out of the first pit 101 under the tension between the first pit 101 and the adhesive microspheres without external force. In addition, the micron-sized adhesive microspheres will not enter the second pit 102.

[0036] 2. As the microgravure roller 1 continues to rotate, the second scraper 12 at the rear end of the first material box 2 scrapes off the organic adhesive slurry on the periphery of the microgravure roller 1 and flows back to the first material box 2, so that only the first pit 101 on the microgravure roller 1 contains organic adhesive slurry. Due to surface tension, the adhesive microspheres in the first pit 101 will not be scraped off.

[0037] 3. The peripheral wall of the micro-gravure roller 1 containing the organic binder slurry enters the second material box 3. The inorganic oxide particles (microstructure of inorganic oxide slurry) in the second material box 3 enter the second pit 102. Since both the inorganic oxide particles and the second pit 102 are nanoscale in size, the binder microspheres will not fall out of the first pit 101 under the tension between the first pit 101 and the binder microspheres without external force.

[0038] 4. As the microgravure roller 1 continues to rotate, the third scraper 13 at the rear end of the second material box 3 scrapes the inorganic oxide particle slurry off the peripheral wall of the microgravure roller 1 and flows back to the second material box 3, so that only the second pit 102 on the microgravure roller 1 contains inorganic oxide slurry. Due to surface tension, the inorganic oxide particles in the second pit 102 will not be scraped off.

[0039] 5. The approach roller 4 drives the diaphragm 5 to come into contact with the micro-gravure roller 1. When the diaphragm 5 is running, the organic adhesive slurry in the first pit 101 and the inorganic oxide slurry in the second pit 102 are simultaneously coated on the diaphragm 5 to obtain a diaphragm 5 with inorganic oxide slurry and organic adhesive slurry.

[0040] In this embodiment, the inorganic oxide slurry is formed by mixing inorganic oxide particles with an oily solvent. The inorganic oxide particles are alumina ceramic particles. The organic adhesive slurry is formed by mixing polyvinylidene fluoride (PVDF) particles with an oily solvent. The oily solvent in the ceramic particle slurry and the organic adhesive slurry is the same. This is to prevent the following situation: if the inorganic oxide slurry still uses an aqueous solvent according to the original formula, and the adhesive uses an oily solvent, there is a risk of contamination from both solvents. Through the above design, after the oily solvent in the first material box 2 enters the second recess 102, the alumina ceramic particles (microstructure) in the second material box 3 can still enter the second recess 102. At the same time, it also avoids the situation where the adhesive microspheres fall into the second material box 3.

[0041] In this embodiment, the alumina ceramic particles (material) include at least alumina, and also include one or more of silicon dioxide, magnesium oxide, or calcium oxide.

[0042] In other embodiments, the oxides in the inorganic oxide slurry include solid electrolytes of oxide systems, such as lithium steel titanium oxide (LLTO) with a perovskite structure, lithium steel zirconium oxide (LLZO) with a garnet structure, fast ion conductors (LISICON, NASICON), etc.

[0043] In other embodiments, the organic adhesive slurry may be an SBR adhesive, or one or more of a polyvinyl alcohol adhesive or a carboxymethyl cellulose adhesive.

[0044] The oily solvent is one or more of acetone, N-methylpyrrolidone, dimethylformamide, dimethylacetamide, and dimethyl sulfoxide. Preferably, in this embodiment, the oily solvent is N-methylpyrrolidone (NMP).

[0045] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A microgravure coating mechanism, comprising a microgravure roller, a proximity roller, and a material box, characterized in that: The material box is used to hold organic adhesive slurry with a particle size of micrometers and inorganic oxide slurry with a particle size of nanometers. The peripheral wall of the microgravure roller is provided with a plurality of first and second recesses. The opening and depth of the first recesses are at the micrometer level, and the opening and depth of the second recesses are at the nanometer level. When the microgravure roller rotates, its peripheral wall passes through the material box, and the organic adhesive slurry and inorganic oxide slurry in the material box enter the first and second recesses respectively. The approach roller is used to support the diaphragm and drive the diaphragm to abut or separate from the microgravure roller. When the microgravure roller rotates, the organic adhesive slurry in the first recess and the inorganic oxide slurry in the second recess are simultaneously coated on the diaphragm. The material box includes a first material box and a second material box, which are arranged sequentially along the rotation direction of the microgravure roller. The first material box is used to hold organic adhesive slurry with a particle size of micrometers, and the second material box is used to hold inorganic oxide slurry with a particle size of nanometers. Both the first and second material boxes are equipped with scrapers, which scrape excess organic adhesive slurry on the microgravure roller back to the first material box and excess inorganic oxide slurry on the microgravure roller back to the second material box.

2. The micro-coating mechanism according to claim 1, characterized in that: The first and second pits are in the shape of one or more of the following: circular, polygonal, pentagonal, BT dot and FM dot.

3. A diaphragm coating device, characterized in that: Includes the micro-gravure coating mechanism as described in claim 1 or 2.

4. A diaphragm coating method, characterized in that: Based on the diaphragm coating equipment according to claim 3, an inorganic oxide particle and an organic binder slurry are simultaneously coated onto the diaphragm using a micro-gravure roller. The organic binder slurry and the inorganic oxide slurry use the same solvent. The organic binder slurry and the inorganic oxide slurry are stored in a first pit and a second pit on the micro-gravure roller, respectively. The size of the first pit is on the micrometer scale, and the size of the second pit is on the nanometer scale. The first pit and the second pit are staggered.

5. The diaphragm coating method according to claim 4, characterized in that: The inorganic oxide slurry is formed by mixing inorganic oxide particles with an oily solvent, and the organic adhesive slurry is formed by mixing organic adhesive particles with an oily solvent.

6. The diaphragm coating method according to claim 5, characterized in that: The organic adhesive particles include one or more of polyvinyl alcohol, carboxymethyl cellulose, or polyvinylidene fluoride; the inorganic oxide particles include one or more of alumina ceramic particles, lithium steel titanium oxide particles, lithium steel zirconium oxide, or fast ion conductors.

7. The diaphragm coating method according to claim 6, characterized in that: The organic adhesive particles are polyvinylidene fluoride adhesive particles.

8. The diaphragm coating method according to claim 6, characterized in that: The inorganic oxide particles are alumina ceramic particles, which include at least alumina, and also include one or more of silicon dioxide, magnesium oxide, or calcium oxide.

Images