102450 battery

Analysis of 102450 battery diaphragm coating technology and methods

In recent years, with the rise of the power 102450 battery market, wet-coated diaphragms have become increasingly popular in China. There are even views in the industry that wet-coated diaphragms will dominate the future power battery diaphragm market. 102450 battery "wet method + coating" has become the industry-recognized diaphragm development direction. Today, the editor has sorted out the relevant content about coating slurry formula and coating process. Welcome to read and leave a message to supplement the information. 102450 battery diaphragm coating technology methods require different coating technologies according to the downstream requirements for specific performance and the positioning of 102450 battery diaphragm products. As for coating, its technical core lies in the slurry formula. At the same time, the slurry accounts for a large proportion of the cost in diaphragm coating. Generally, the slurry accounts for 65% of the total coating cost. The development direction of power lithium batteries is a high-output, high-capacity, and fast-charging mode. The requirements for diaphragm coating technology and process will also be more diversified, and the continuous innovation of the formula will also become the core competitiveness of coating. The diaphragm ceramic coating slurry mainly includes four main components: ceramic particles, binders, solvents and additives. Different slurry ratios are required for different application scenarios. The rigid support of ceramics makes the ceramic modified diaphragm have excellent thermal stability and dimensional integrity at high temperatures, and supports the maintenance of the diaphragm structure at high temperatures. At high temperatures, the diaphragm matrix is closed and transparent, and the uncoated diaphragm shrinks severely. The coated 102450 battery diaphragm has greatly improved anti-shrinkage due to the ceramic layer, and has better mechanical properties and safety. 102450 battery diaphragm coating method, flexible and diverse diaphragm coating is not technically difficult, and can be achieved by gravure roller coating, dip coating, narrow coating or spraying. Domestic mainstream base film manufacturers and a large number of OEM factories can achieve it. Gravure roller coating Gravure roller coating process is currently a commonly used coating method. The micro-gravure roller takes the slurry out of the slurry box, and the excess coating is scraped off by a fixed thickness scraper, and then coated on the diaphragm under pressure. The principle of this method is relatively simple, the groove capacity of the gravure roller is easy to control, and the product precision is good. The disadvantage is that due to the high hardness of the alumina ceramic particles, the anilox roller is easy to wear, which will cause the coating to gradually become thinner during the continuous coating process, and a new roller needs to be replaced; when the coating target thickness changes, the roller needs to be replaced, and it cannot be flexibly adjusted. Narrow slit extrusion coating Narrow slit extrusion coating, referred to as narrow coating, is a process of extruding the slurry from the extrusion nozzle onto the diaphragm under a certain pressure. The coating thickness is controlled by the width of the extrusion nozzle and the metering pump. This process is applicable to a wide range of viscosities, has good product precision, can coat thin layers, and has a high coating speed, but the maintenance of the extrusion nozzle is relatively difficult. Dip coating The basic principle of dip coating is to soak the 102450 battery diaphragm in a slurry of a certain concentration for a certain period of time, take it out and dry it or bake it, and obtain a coating of a certain thickness on the surface of the diaphragm. The principle and operation of this method are simple, but the thickness control is relatively difficult. Electrospinning Electrospinning is a process of spraying the slurry onto the diaphragm through the electric field force, giving the slurry an electric charge. Under the action of the electric field force, the slurry breaks through the surface tension and forms nanowires that are sprayed toward the diaphragm. This process has the advantages of a wide range of applicable materials, easy operation, large specific surface area, high porosity, good fiber uniformity, and high yield, but it has the disadvantages of low crystallinity and orientation, poor mechanical properties, and mechanical properties, and needs to be optimized through modification methods such as heat treatment and blending. At present, the equipment for coating and processing of 102450 battery separators basically needs to be imported, with stable supply and compact equipment. One production line requires an investment of 1.5-2 million yuan, and the output is about 4 million square meters/year. For enterprises that have both base film production and coating processing capabilities, generally each base film production line needs to be equipped with 10 coating production lines. Most 102450 battery separator coating manufacturers use gravure roller coating method because the processing speed and precision of gravure roller coating are high, the process is mature, and the processing and maintenance of the roller are relatively simple and low cost. Narrow coating is often also selected as the preferred option because the process has high precision, fast processing speed, and great viscosity flexibility, but the processing and maintenance of the narrow coating extrusion nozzle are relatively difficult and the cost is relatively high. Comparison of wet coating and dry double-pull coating 1. Dry base film: If the wet PE base film is directly used in the battery, it cannot be used or is not easy to use because the thermal temperature of the base film is too low. In order to improve thermal stability, the surface of the base film must be coated to make up for the 50% defect. However, will there be any improvement through different coating technologies? Born with a disability and a weak body, it is useless to wear armor outside. Wet: In the field of power lithium batteries, many manufacturers are switching to wet coating, and wet single layer is also in use. The pore size of wet diaphragms is uniform, which is incomparable to dry diaphragms. The pore size of dry base membranes is not uniform, so what is the use of coating? 2. Air permeability Dry: The pore size of dry double-pull base membranes only needs to be uniform enough. The battery can be charged and discharged without problems, and there is no short circuit. The overall safety is good, so it does not need to be as uniform as the wet membrane. Although the pore size of the wet membrane is more uniform, the pore size itself is too small. In addition to coating, how to ensure high air permeability. Wet: Wet 102450 battery diaphragms can be made with high air permeability or low air permeability according to battery requirements. 3. Melting point The dry 102450 battery diaphragm and the wet diaphragm are quite different in material, and the melting point difference is more than 40 degrees. At 120 degrees, 70%-80% of the wet-process diaphragms will close up; at 150 degrees, the dry-process diaphragms can still maintain a relatively good state. The lower melting point is the biggest difference between the two diaphragms, which is determined by the characteristics of the material itself, but as long as it meets the requirements for the use of lithium batteries. High-performance lithium batteries require diaphragms with uniform thickness and excellent mechanical properties, air permeability, and physical and chemical properties. The excellence of the diaphragm directly affects the capacity, cycle capacity, and safety performance of the 102450 battery. A diaphragm with excellent performance plays an important role in improving the overall performance of the battery.

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