The purpose and function of the lithium -ion battery diaphragm -Lithium - Ion Battery Equipment
In the structure of the 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 characteristics of the battery capacity, cycle, and safety performance. Optomic septum with excellent performance has an important role in improving the comprehensive performance of the battery. Below is a detailed introduction of the role of lithium ion battery diaphragm.
[Lithium ion battery diaphragm] The function of lithium -ion battery diaphragm is functional
The role of lithium ion battery diaphragm
The four key materials of lithium -ion batteries are positive poles, negative materials, electrolytes, and diaphragms. The main function of the diaphragm is to isolate positive and negative poles and prevent electrons from crossing, and at the same time allow ions to pass, so as to complete the rapid transmission between lithium ions between positive and negative electrodes during the charging process. The advantages and disadvantages of diaphragm performance directly affect the quality of battery resistance, discharge capacity, cycle service life, and battery safety performance. The thinner the diaphragm, the higher the pore rate, the smaller the internal resistance of the battery, and the better the high -power discharge performance.(Lithium - Ion Battery Equipment)
Lithium -ion battery diaphragm is a porous plastic film, which include several types such as weaving film, non -woven membranes (non -woven fabrics), micropores, and crushing membranes. The film, and the PP/PE/PP three -layer composite film.
The difficulty of diaphragm production lies in the engineering technology and matrix materials of pores. Among them, the engineering technology of the pores includes the pore making process, production equipment and product stability; the substrate materials include polypropylene, polyethylene materials and additives. The production process of polyolefins is divided into two categories: dry method and wet method. Among them, the dry method is divided into one -way stretching process and two -way stretching process.
The one -way stretching process of the dry method is to stretch the film at low temperature to form a micro -defect, and then pull the defects open at high temperature to form micropores. Because it is one -way stretching, its micro -hole structure is flat and long, and the horizontal strength is poor, but the advantage is that there is almost no heat contraction in horizontal. CELGARD has the patent of this process. Later, Japan ’s Utime Company purchased its patent use right to use this method to produce single -layer PP, PE and three -layer PP/PE/PP composite film.
The two -way stretching process of the dry method is to add a β crystal -shaped improvemeter to the polypropylene to cause density differences between different phase. During the stretching process, the crystal is transformed into micropores. This technology was independently developed by the Institute of Chemistry of the Chinese Academy of Sciences. Xinxiang Grene New Energy Materials Co., Ltd. and Guilin Xinshi Technology Co., Ltd. and the Chinese Academy of Sciences used this method to produce single -layer PP membranes.
The wet method is also known as a thermal phase separation method. It is used to add pores (such as liquid hydrocarbons or some small molecular substances) to the polyolefin resin. The extract agent is eluted and residues. After drying, it can be prepared to prepare the interdependent micropilum membrane material. It is currently mainly used for single -layer PE membrane. Companies that adopt this method include Japanese Asahi, east and the United States ENTEK.
The stretching process of the dry law is relatively simple, without pollution. It is a common preparation method for lithium -ion battery diaphragm. However, the stretching of this method is relatively small, about 1 ~ 3, and the pore diameter and gap rate are difficult to control. It is easy to cause perforation during stretching, and it cannot be prepared for thin film. The micro -hole diameter obtained by the wet method is small and uniform, and the stretch can reach 5 ~ 7. It is not easy to cause perforation. It can make a thinner diaphragm and make the battery capacity density higher.
[Lithium ion battery diaphragm] The function of lithium -ion battery diaphragm is functional
The role of lithium ion battery diaphragm
The four key materials of lithium -ion batteries are positive poles, negative materials, electrolytes, and diaphragms. The main function of the diaphragm is to isolate positive and negative poles and prevent electrons from crossing, and at the same time allow ions to pass, so as to complete the rapid transmission between lithium ions between positive and negative electrodes during the charging process. The advantages and disadvantages of diaphragm performance directly affect the quality of battery resistance, discharge capacity, cycle service life, and battery safety performance. The thinner the diaphragm, the higher the pore rate, the smaller the internal resistance of the battery, and the better the high -power discharge performance.(Lithium - Ion Battery Equipment)
Lithium -ion battery diaphragm is a porous plastic film, which include several types such as weaving film, non -woven membranes (non -woven fabrics), micropores, and crushing membranes. The film, and the PP/PE/PP three -layer composite film.
The difficulty of diaphragm production lies in the engineering technology and matrix materials of pores. Among them, the engineering technology of the pores includes the pore making process, production equipment and product stability; the substrate materials include polypropylene, polyethylene materials and additives. The production process of polyolefins is divided into two categories: dry method and wet method. Among them, the dry method is divided into one -way stretching process and two -way stretching process.
The one -way stretching process of the dry method is to stretch the film at low temperature to form a micro -defect, and then pull the defects open at high temperature to form micropores. Because it is one -way stretching, its micro -hole structure is flat and long, and the horizontal strength is poor, but the advantage is that there is almost no heat contraction in horizontal. CELGARD has the patent of this process. Later, Japan ’s Utime Company purchased its patent use right to use this method to produce single -layer PP, PE and three -layer PP/PE/PP composite film.
The two -way stretching process of the dry method is to add a β crystal -shaped improvemeter to the polypropylene to cause density differences between different phase. During the stretching process, the crystal is transformed into micropores. This technology was independently developed by the Institute of Chemistry of the Chinese Academy of Sciences. Xinxiang Grene New Energy Materials Co., Ltd. and Guilin Xinshi Technology Co., Ltd. and the Chinese Academy of Sciences used this method to produce single -layer PP membranes.
The wet method is also known as a thermal phase separation method. It is used to add pores (such as liquid hydrocarbons or some small molecular substances) to the polyolefin resin. The extract agent is eluted and residues. After drying, it can be prepared to prepare the interdependent micropilum membrane material. It is currently mainly used for single -layer PE membrane. Companies that adopt this method include Japanese Asahi, east and the United States ENTEK.
The stretching process of the dry law is relatively simple, without pollution. It is a common preparation method for lithium -ion battery diaphragm. However, the stretching of this method is relatively small, about 1 ~ 3, and the pore diameter and gap rate are difficult to control. It is easy to cause perforation during stretching, and it cannot be prepared for thin film. The micro -hole diameter obtained by the wet method is small and uniform, and the stretch can reach 5 ~ 7. It is not easy to cause perforation. It can make a thinner diaphragm and make the battery capacity density higher.
