Process Interpretation of Dry Process Lithium Battery Diaphragm Production Line
DATE：2023/5/10 15:12:53 / READ： / SOURCE：This station
The production line of lithium battery diaphragm has complex process and high technical barrier. High performance lithium battery requires the diaphragm to have uniform thickness and excellent mechanical properties (including tensile strength and puncture resistance strength), air permeability, physical and chemical properties (including wettability, chemical stability, thermal stability, safety). The excellence of the separator directly affects the capacity, cycling ability, and safety performance of lithium batteries.
According to the mechanism of microporous pore formation, membranes can be divided into two types: dry method and wet method, with dry method being divided into single pulling and double pulling. Currently, dry process is the main method in China.
The dry process of lithium battery separator production line involves first melting, squeezing, and blowing polyolefin resin to form a crystalline polymer film, followed by crystallization heat treatment and annealing to obtain a highly oriented film structure. Then, it is stretched at high temperature to test the separation of crystal cross sections and form a porous structure battery separator. In dry process, it can also be divided into unidirectional stretching and biaxial stretching.
Dry drawing is a type of polyethylene (PE) or polypropylene (PP) polymer with good flowability and low molecular weight. It utilizes the manufacturing principle of hard elastic fibers to first prepare high directional low crystalline polyene, which forms micro defects such as silver lines through casting and low-temperature stretching. Then, defects are opened through high-temperature annealing to obtain a microporous film with uniform pore size and uniaxial orientation.
Dry double pulling, due to PP's β The crystal is hexagonal, with single crystal nucleation and loosely arranged wafers, growing radially into a divergent bundle like crystal structure without a complete crystal structure. Under the action of heat and stress, it will become denser and more stable α After absorbing a large amount of impact energy, crystals will create pores inside the material. This process is achieved by adding nucleating agents to PP β Crystalline modifier, which utilizes PP to form micropores through different phase transitions during the stretching process.
The dry process of lithium battery separator production line involves first melting, squeezing, and blowing polyolefin resin to form a crystalline polymer film, followed by crystallization heat treatment and annealing to obtain a highly oriented film structure. Then, it is stretched at high temperature to test the separation of crystal cross sections and form a porous structure battery separator. In dry process, it can also be divided into unidirectional stretching and biaxial stretching.
Dry drawing is a type of polyethylene (PE) or polypropylene (PP) polymer with good flowability and low molecular weight. It utilizes the manufacturing principle of hard elastic fibers to first prepare high directional low crystalline polyene, which forms micro defects such as silver lines through casting and low-temperature stretching. Then, defects are opened through high-temperature annealing to obtain a microporous film with uniform pore size and uniaxial orientation.
Dry double pulling, due to PP's β The crystal is hexagonal, with single crystal nucleation and loosely arranged wafers, growing radially into a divergent bundle like crystal structure without a complete crystal structure. Under the action of heat and stress, it will become denser and more stable α After absorbing a large amount of impact energy, crystals will create pores inside the material. This process is achieved by adding nucleating agents to PP β Crystalline modifier, which utilizes PP to form micropores through different phase transitions during the stretching process.
Author：admin