(this figure is the schematic diagram of power battery diaphragm dry single drawing production line)

The main function of the longitudinal pull diaphragm of lithium battery is to separate the positive and negative poles of the battery, so as to prevent the two poles from contacting and short circuiting. The micropores in the film can let lithium ions pass through and form a charge and discharge circuit. The diaphragm is the core and key material in lithium battery, and it is also a high value-added material with high technical barriers in lithium battery. Its performance determines the interface structure, internal resistance, battery capacity, life and safety performance of the battery.

In the structure of lithium battery, the diaphragm is one of the key inner components. The performance of the diaphragm determines the interface structure and internal resistance of the battery, which directly affects the capacity, circulation 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 diaphragm is a layer of porous plastic film, which is a high value-added material with high technical barriers 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 single pull extrusion production line, which is equipped with MDO (unidirectional stretching) unit newly developed by our company, which can achieve stable and uniform stretching of products, uniform pores, and greatly reduce the defective rate.

Lithium battery diaphragm production line is divided into: dry unidirectional stretching production line; Dry biaxial stretching production line; Wet extraction biaxial stretching production line.

Dry unidirectional stretching production line: the dry unidirectional stretching process is to produce hard elastic fibers, take PP or PE as the main raw material, mix various brands of auxiliary materials, and fully stir to prepare high-oriented polypropylene or polyethylene films with low crystallinity, and then anneal at high temperature to obtain high crystallinity oriented films. The film is stretched at low temperature to form micro defects, and then the defects are pulled apart at high temperature to form micropores. In terms of equipment, after being extruded by tape casting method, it is laminated by laminating machine and then stretched in one direction, and then layered and sliced by laminating machine and slitting machine to produce unidirectional stretched lithium diaphragm. Jinweier lithium battery dry single pull production line is equipped with high-precision testing 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 stretching production line: the dry biaxial stretching 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 is added with β Crystal modifier, which takes advantage of the density difference between different phases of polypropylene to form micropores during the stretching process, is used to produce the isolation membrane of single-layer PP membrane battery. In terms of equipment, after extrusion by tape casting, bi-directional stretching and winding, slitting, to produce bi-directional stretching 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 middle and low-end market

Wet biaxial stretching production line: the wet process takes PE as the main raw material, mixes liquid hydrocarbon or some small molecular substances with polyolefin resin, fully stirs, heats and melts, forms a uniform mixture, then cools down for phase separation, presses the membrane, then heats the membrane to the temperature close to the melting point, carries out biaxial stretching to orient the molecular chain, holds for a certain period of time, and elutes the residual solvent with volatile substances, Microporous membrane materials that connect with each other can be prepared. In terms of equipment, the wet biaxially stretched lithium diaphragm is produced by two-way stretching after tape casting extrusion, forming holes through extraction process, and then winding and slitting after vertical and horizontal stretching. Jinweier wet double pull lithium battery diaphragm line is equipped with high-precision detection instruments, and adopts the production process jointly developed with China's famous scientific research institutions. 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.

(dry single pull lithium battery diaphragm and electron microscope)

Product features: lithium ion battery diaphragm is a kind of polymer functional material with nano pores. Rechargeable lithium ion battery has the characteristics of high specific energy, long cycle life, no memory effect, and is safe, reliable and can be charged and discharged quickly. It meets the great development needs of energy and environmental protection in today's countries, and its usage in all walks of life is increasing rapidly.

1. The thickness uniformity is good, and the micropore distribution is average, which is conducive to the consistency of lithium-ion batteries;

2. The micropore has low tortuosity, good permeability, strong liquid retention ability and small internal resistance of the battery;

3. High temperature resistance, no transverse thermal shrinkage, high film breaking temperature, 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 uses of products: lithium ion batteries for power systems such as electric vehicles, electric motorcycles, electric bicycles, electric tools, large-scale energy storage lithium-ion batteries, and various digital lithium-ion batteries.

Parameters of lithium battery diaphragm dry single drawing production line (please consult the sales engineer for details)