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Lithium Battery Separator Biaxial Orientation Extrusion Line
（Schematic diagram of double pull lithium battery diaphragm production line，Extraction mode）
The main function of lithium battery diaphragm is to separate the positive and negative poles of the battery to prevent short circuit due to contact between the two poles. The micropores in the film can allow lithium ions to pass through and form a charge discharge circuit. Diaphragm is not only the core key material in lithium battery, but also a high value-added material with the highest technical barriers in lithium battery. Its performance determines the interface structure, internal resistance, battery capacity, service life and safety performance of the battery.
In the structure of lithium battery, diaphragm is one of the key inner components. The performance of the diaphragm determines the interface structure and internal resistance of the battery, and directly affects the capacity, cycle and safety performance of the battery. The diaphragm with excellent performance plays an important role in improving the comprehensive performance of the battery. The popular description of the diaphragm is a layer of porous plastic film, which is a high value-added material with the highest technical barrier among lithium battery materials, accounting for about 20% - 30% of the cost of lithium battery.
Gwell machinery specializes in manufacturing PP / PE lithium battery diaphragm dry and wet biaxial tensile extrusion production lines. The production line is equipped with MDO (longitudinal tensile) and TDO (transverse tensile) units newly developed by our company, which can achieve stable and uniform tensile of products and greatly reduce the defective rate.
（Schematic diagram of double pull lithium battery diaphragm production line）
Lithium battery diaphragm production line is divided into: dry unidirectional stretching production line; Dry biaxial drawing production line; Wet biaxial drawing production line.
Dry unidirectional stretching production line: the dry unidirectional stretching process is to produce hard elastic fiber, take PP or PE as the main raw material, mix various brands of auxiliary materials, fully stir, prepare low crystallinity oriented polypropylene or polyethylene film, and then anneal at high temperature to obtain high crystallinity oriented film. The film is stretched at low temperature to form micro defects, and then the defects are opened at high temperature to form micropores. In terms of equipment, after extrusion by tape casting method, multi-layer composite and unidirectional stretching are carried out by laminating machine, and then the stretched multi-layer diaphragm is layered and cut by laminating machine and slitting machine to produce unidirectional stretched lithium diaphragm. Jinweier lithium battery dry process single pull production line is equipped with high-precision detection instruments and adopts the production process jointly developed with famous scientific research institutions in China. The main production thickness is 16 μ M to 40 μ M lithium ion battery separators of different specifications. Scope of application: large lithium ion power batteries (electric vehicles, electric motorcycles, electric tools, large energy storage equipment, large batteries for military industry)
Dry biaxial drawing production line: the dry biaxial drawing process is a process with independent intellectual property rights developed by the Institute of chemistry, Chinese Academy of Sciences in the early 1990s. With PP as the main raw material, polypropylene was added with nucleating agent β The crystal form modifier is used to produce the isolation membrane of single-layer PP membrane battery by using the difference of density between different phases of polypropylene to form micropores during stretching. In terms of equipment, after extrusion by tape casting, bi-directional tensile winding and slitting to produce bi-directional tensile lithium diaphragm. Jinweier lithium battery diaphragm equipment is equipped with high-precision detection instruments and adopts the production process jointly developed with famous scientific research institutions in China. The main production thickness is 12 μ M to 40 μ M double pull lithium ion battery separators of different specifications. At present, more than one third of China's production capacity uses dry double drawing process, and the products occupy a large proportion in the medium and low-end market
Wet biaxial stretching production line: in the wet process, PE is used as the main raw material, liquid hydrocarbon or some small molecular substances are mixed with polyolefin resin, fully stirred, heated and melted to form a uniform mixture, then cooled for phase separation, pressed to obtain the diaphragm, heated to the temperature close to the melting point, biaxial stretching is carried out to orient the molecular chain, and finally kept for a certain time, Microporous membrane materials can be prepared by eluting the residual solvent with volatile substances. In terms of equipment, the wet biaxially stretched lithium diaphragm is produced by biaxially stretching after tape casting extrusion, forming holes through extraction process, winding and slitting after longitudinal and transverse stretching. Jinweier wet double pull lithium battery diaphragm line is equipped with high-precision detection instrument and adopts the production process jointly developed with famous scientific research institutions in China. The main production thickness is 8 μ M to 25 μ M lithium ion battery separators of different specifications. Scope of application: high performance lithium ion battery, etc.
（Diaphragm and electron microscope of double pull lithium battery）
Product features: lithium ion battery separator is a polymer functional material with nano micropores. Rechargeable lithium ion battery has the characteristics of high specific energy, long cycle life and no memory effect. It also has the characteristics of safety, reliability and rapid charge and discharge. It meets the great development needs of energy and environmental protection in various countries, and its use in all walks of life is increasing rapidly. The diaphragm produced by biaxial stretching process has higher safety, better thermal stability and current blocking, higher ion permeability, superior high current charging and discharging performance and longer service life. It is suitable for the manufacture of lithium ion batteries with large capacity such as power batteries.
1. Good thickness uniformity and average micropore distribution, which is conducive to the consistency of lithium-ion batteries;
2. Low tortuosity of micropores, good air permeability, strong liquid holding capacity and small internal resistance of battery;
3. High temperature resistance, no transverse thermal shrinkage, high film breaking temperature and good safety performance;
4. High tensile strength and good mechanical properties;
5. The specification of the production line is generally 1000-2400mm wide. The specific specification is determined according to the production process and can be customized.
Main applications: power lithium-ion batteries for electric vehicles, electric motorcycles, electric bicycles, electric tools and other systems, large energy storage lithium-ion batteries, and various digital lithium-ion batteries
Lithium Battery Separator Biaxial Orientation Extrusion Line
| Type |
Single screw GWS75 |
Single screw GWS90 |
Parallel twin screw GWP75 |
Single screw GWS75 / 90 / 75 |
| raw material | PP 、 PE | PP 、 PE | PP 、 PE | PP 、 PE |
| Product structure | single layer | single layer | single layer | A / B / A |
| Product width | 2000mm | 2000mm | 2000mm | 2000mm |
| Product thickness | 16um - 25um | 16um - 25um | 16um - 25um | 12um - 38um |
| capacity | 70KG/H - 100KG/H | 90KG/H - 110KG/H | 90KG/H - 110KG/H | 100KG/H - 130KG/H |
| speed | 50 m/min | 50 m/min | 50 m/min | 50 m/min |