Factors Influencing Thermal Shrinkage Of Ceramic Separator
The lithium battery separators currently used in the market are mainly: polyolefin separators, non-woven-based separators and other types of separators.
In order to improve the reliability of lithium-ion batteries, the method of adding inorganic ceramic materials to make ceramic separators of lithium-ion batteries has received a lot of attention, and the inorganic substances used are generally alumina, boehmite, and the like. This approach takes advantage of the high strength and high temperature resistance of inorganic ceramic materials. However, the inorganic ceramic material cannot be directly attached to the porous polyolefin separator, so a binder is required to provide adhesion between the inorganic ceramic particles and between the inorganic ceramic particles and the porous polyolefin separator.
The polyolefin separator itself has poor heat shrinkage resistance, so it is generally necessary to improve its heat shrinkage performance through an additional coating. Therefore, the basic requirement for the coating is good thermal shrinkage resistance and little effect on properties such as ion permeability and the stability of the coating film in the battery.
Ceramic coatings are popular choices, such as alumina coatings, boehmite coatings. The thermal shrinkage performance of the coating on the separator plays a decisive role in the thermal shrinkage performance of the entire lithium-ion battery separator.
The particle size of alumina particles;
The crystal form of alumina;
Types of binders;
The amount of binder;
Coalescent;
Coating Thickness.
The above six factors are all important factors in determining the thermal shrinkage of the ceramic separator.
