Coating preparation device of chemical battery diaphragm

Abstract

The utility model discloses a coating preparation device for a chemical battery diaphragm, which is provided with a battery diaphragm comprising a base material, an organic ceramic coating and a PVDF (Polyvinylidene Fluoride) coating, the PVDF coating is printed and coated on the organic ceramic coating in a dot-matrix manner, each printing and coating point is a round point, and the printing and coating points are uniformly distributed in a 45-degree * 45-degree crossed net shape along the rolling diameter direction of the base material. Specifically, a printing plate in screen printing equipment is made of rolled metal foil, the metal foil is provided with a plurality of round holes to form a crossed net shape, the printing plate is surrounded into a cylinder shape after being provided with the holes and is welded and formed, and the metal foil is stainless steel foil or copper foil. According to the utility model, a metal foil printing plate preparation process and a dot-matrix PVDF printing and coating process are adopted, so that the problem of non-uniform distribution of the PVDF coating is solved, the transmittance requirement of electrolyte and the thickness requirement of the coating are ensured, and the power coefficient and the product quality of lithium and sodium ion batteries are improved.

Description

Technical Field

[0001] The utility model relates to the field of chemical liquid battery double-sided double-layer coated diaphragms, in particular to a coating preparation device for chemical battery diaphragms. Background Art

[0002] Lithium and sodium ion battery coated diaphragms are used in high-end digital batteries, vehicle power batteries, safe energy storage batteries and other scenarios. The coating thickness error will affect the electrochemical conversion energy of the chemical battery, and the uneven coating distribution will affect the weather resistance and safety of the chemical battery product. Figure 2 As shown in the figure, the "organic ceramic coating + polyvinylidene fluoride coating" double-sided multi-layer coated diaphragm products produced by the leading domestic lithium battery diaphragm companies are Figure 3 As shown, after the product characterization was magnified 30 times, it can be seen that the second coating PVDF has problems such as "uneven distribution" and "irregular particle size", which have not been solved.

[0003] The reason for the technical barriers in this industry is that the first coating of the diaphragm, AL2O3 or SiO2 inorganic ceramic layer, is a micron-scale grain structure that cannot withstand the external pressure generated by the secondary coating process. After being compressed, it will peel off and squeeze the micropores of the diaphragm substrate, causing the semi-finished products of the first two sections to be scrapped. A layer of PVDF polyvinylidene fluoride layer or REL aramid fiber layer is coated on the ceramic coated diaphragm, and the coated surface area needs to be between 20-30% to ensure the flow performance of the electrolyte, improve the thermal stability of the battery, and enhance the adhesion between the coated diaphragm and the positive and negative electrodes. The coating equipment currently used in the market all adopts the coating unit and production process of "disc stacking rotary spin coating", which only solves the process and technical problems of the carrier base film and the organic ceramic coating not being damaged by extrusion, but cannot solve the problems of "uneven distribution" and "particle size" of the PVDF coating.

[0004] Regarding the structure of screen printing equipment, the polyester woven materials currently used in screen printing plate making, from 300 mesh to 460 mesh specifications, have been tested many times, but none of them can meet the requirements of uniform distribution of PVDF coating, and the service life of the printing plate is short and the replacement frequency is high. The all-nickel electroformed screen material used in screen printing plate making can increase the material life of the printing plate, but due to the material thickness, mesh size, mesh opening rate and other reasons after plate making, it is impossible to achieve a coating dry weight of 1.2-1.5g / m 2 technical indicators. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the purpose of the utility model is to provide a coating preparation device for a chemical battery separator to improve the power coefficient and product quality of lithium and nano-ion batteries.

[0006] In order to solve the above technical problems, the technical solution adopted by the utility model is:

[0007] The utility model discloses a coating preparation device for a chemical battery separator, which comprises a battery separator comprising a substrate, an organic ceramic coating and a PVDF coating. The PVDF coating is dot-printed on the organic ceramic coating, each printing dot is a round dot, and the printing dot is evenly distributed in a cross-net shape of 45°×45° along the roll diameter direction of the substrate.

[0008] The coating area of ​​PVDF on the organic ceramic coating in the utility model is 20%-30%, and the dry weight of each printed dot is 1.2-1.5g / m 2 .

[0009] In the utility model, the spacing between the dots on the straight line obliquely extending at 45° along the winding diameter of the substrate is 0.8-1.0 mm, and the diameter of each dot is 0.4-0.45 mm.

[0010] The utility model discloses a coating preparation device for a chemical battery diaphragm, which mainly comprises a machine body, a film guide roller, a substrate traction roller and a screen printing device. The printing plate in the screen printing device is made of a rolled metal foil, and the metal foil is provided with a plurality of circular holes to form a cross mesh. After the holes are opened, the printing plate is wrapped into a cylindrical shape and welded into shape. The metal foil is a stainless steel foil or a copper foil.

[0011] In the utility model, when stainless steel foil is used as the plate-making substrate, a plurality of circular holes are punched on a platform-type laser punching machine; when copper foil is used as the plate-making substrate, a plurality of circular holes should be formed by an imaging etching process.

[0012] In the utility model, a plurality of circular holes are evenly distributed in a cross-net shape of 45°×45° along the radial direction of the printing plate roll, the spacing between the circular holes on the 45° oblique straight line along the radial direction of the printing plate roll is 0.8-1.0mm, and the diameter of each circular hole is 0.4-0.45mm.

[0013] In the utility model, the width of the printing plate is not greater than 1300 mm.

[0014] In the utility model, the film-walking width of the substrate traction roller can accommodate two groups of screen printing equipment for docking and printing, and the two groups of screen printing equipment are staggered and distributed on the film-walking path of the substrate traction roller.

[0015] The beneficial effects of the utility model are:

[0016] 1. When dot-matrix PVDF is coated on the organic ceramic coating, the coating area should be controlled between 20-30%, the dot diameter of the coating position should be 0.4-0.45 (mm), and the dry weight of the dot-shaped PVDF coating should be 1.2-1.5g / m 2, which is achieved by changing the dot spacing and dot size to ensure the transmittance requirements of the electrolyte and the coating thickness requirements;

[0017] 2. Use 2-5μm stainless steel foil (hand-torn steel) or 7μm rolled steel foil to replace polyester screen and make it into a cylindrical screen printing screen, forming a dot matrix round screen coating device that can be connected to the original coating machine, improving the plate making accuracy and service life;

[0018] 3. Due to the problems of rigidity and strength of circular metal foil printing plates, the maximum manufacturing limit of the printing plate width is 1300mm. When the comprehensive production speed Max 200m / min and the service life greater than 200,000 meters are met, when the working width of the coated product and coating equipment exceeds 1300mm, the method of double-plate staggered series connection can be adopted, and two printing plates of the same specifications can be spliced ​​to produce the coating width required by the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the dot matrix printing structure of the PVDF coating in the utility model;

[0020] Figure 2 It is a structural diagram of a coated battery separator product in the utility model;

[0021] Figure 3 It is related to the characterization of double-layer coated battery separator products in the prior art;

[0022] Figure 4 It is related to the characterization of the double-layer coated battery separator product in the utility model;

[0023] Figure 5 It is a schematic diagram of the structure of the coating preparation device in the utility model;

[0024] Figure 6 It is a side view of the double-plate staggered series structure in the utility model;

[0025] Figure 7 It is a top view of the double-plate staggered series structure in the utility model. DETAILED DESCRIPTION

[0026] The utility model is further described below in conjunction with the accompanying drawings.

[0027] Reference Figure 1As shown, the utility model is a coating preparation device for a chemical battery separator, which has a battery separator including a substrate, an organic ceramic coating, and a PVDF coating. To solve the problem of uneven PVDF coating, the specific process is to perform dot matrix printing on the organic ceramic coating, each printing dot is a dot, and the printing dot is evenly distributed along the substrate roll diameter direction in a 45°×45° cross-net shape, specifically, the spacing between each dot on a 45° oblique straight line along the substrate roll diameter direction is 0.8-1.0mm, forming a better dot matrix dot network distribution area.

[0028] The coating area of ​​PVDF on the organic ceramic coating is controlled between 20% and 30%, the diameter of each dot is 0.4-0.45mm, and the dry weight of each printed dot is 1.2-1.5g / m 2 ,like Figure 2 As shown, this is achieved by changing the dot spacing and dot size to ensure the transmittance requirements of the electrolyte and the coating thickness requirements.

[0029] like Figure 4 The figure shows the coating characterization after 30 times magnification. It can be seen that the dots of the PVDF coating printed by dot matrix are full and evenly distributed, which can ensure the transmittance requirements of the electrolyte and the coating thickness requirements.

[0030] The dot-matrix printing of the PVDF coating can be achieved by a coating preparation device for a chemical battery separator, such as Figure 5 As shown, the equipment mainly includes a machine body 1, a film guide roller 2, a substrate traction roller 3 and a screen printing device 4. The printing plate in the screen printing device 4 is made of a rolled metal foil. The metal foil is provided with a number of circular holes to form a cross mesh. After the holes are opened, the printing plate is wrapped into a cylindrical shape and welded to form. The metal foil is a stainless steel foil or a copper foil. The process technology of using 2-5μm stainless steel foil (hand-torn steel) to replace the polyester screen and make a cylindrical screen printing screen can improve the plate making accuracy and service life.

[0031] After experimental analysis, when using 2-5μm thick stainless steel foil (hand-torn steel) or 7μm rolled steel foil as the plate-making substrate, take a blank with a width of ≤1300mm and a length of ≤690mm, and punch several circular holes on a platform laser punching machine; if copper foil is used as the plate-making substrate, several circular holes should be formed through the imaging etching process.

[0032] The above-mentioned circular holes are evenly distributed in a 45°×45° cross-grid along the radial direction of the printing plate roll. The spacing between the circular holes on the 45° oblique straight line along the radial direction of the printing plate roll is 0.8-1.0mm, and the diameter of each circular hole is 0.4-0.45mm, which can meet the requirements of the PVDF coating dot matrix printing process.

[0033] In order to ensure the rigidity and strength of the metal foil printing plate, the width of the printing plate should not exceed 1300mm. Figure 6 , Figure 7 As shown, when the working width of the coated product and the coating equipment exceeds 1300mm, the film-walking width of the substrate traction roller 3 can accommodate two sets of screen printing equipment to connect with it for printing and coating, and the two sets of screen printing equipment are staggered on the film-walking path of the substrate traction roller 3 to form a double-plate staggered series structure, and two printing plates of the same specifications are spliced ​​to produce the coating width required by the product.

[0034] It should be understood that the technical scope of the utility model is not limited to the contents of the specification. For ordinary technicians in this field, improvements or changes can be made based on the above description, and all these improvements and changes should fall within the scope of protection of the claims attached to the utility model.

Claims

1. A coating preparation device for a chemical battery separator, characterized in that: The invention mainly comprises a machine body (1), a film guide roller (2), a substrate pulling roller (3) and a screen printing device (4). The printing plate in the screen printing device (4) is made of rolled metal foil. The metal foil is provided with a plurality of circular holes to form a cross-net. After the holes are opened, the printing plate is formed into a cylindrical shape and welded into shape. The metal foil is stainless steel foil or copper foil.

2. The coating preparation device for a chemical battery separator according to claim 1, characterized in that: When stainless steel foil is used as the plate-making base material, several circular holes are punched on a flat-bed laser punching machine; when copper foil is used as the plate-making base material, several circular holes should be formed through a developing and etching process.

3. A coating preparation device for a chemical battery separator according to claim 1 or 2, characterized in that: The plurality of circular holes are evenly distributed along the radial direction of the printing plate roll and form a cross-net shape of 45°×45°.

4. The coating preparation device for a chemical battery separator according to claim 3, characterized in that: The spacing between the circular holes on the straight line inclined at 45 degrees along the radial direction of the printing plate is 0.8-1.0 mm, and the diameter of each circular hole is 0.4-0.45 mm.

5. The coating preparation device for a chemical battery separator according to claim 1 or 2, characterized in that: The width of the printing plate is not greater than 1300 mm.

6. The coating preparation device for a chemical battery separator according to claim 5, characterized in that: The film-traveling width of the substrate pulling roller (3) can accommodate two sets of screen printing equipment for docking and printing therewith, and the two sets of screen printing equipment are staggered in distribution on the film-traveling path of the substrate pulling roller (3).

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