Alumina Battery Separator | What's the Future Trend of Lithium Battery Separators?
3.1 Thin Diaphragm Products.
Digital lithium-ion batteries for smartphones, tablets, laptops, wearable smart devices, etc., require thinner film thickness for optimal energy density, as it is crucial to accommodate more electrode materials within a compact volume. Aluminum oxide battery separators for new energy vehicles, electric bicycles, electric tools, and energy storage power stations are focused on enhanced safety performance. Under the premise of ensuring long lifespan, high charge/discharge rates, and high power, the separator thickness tends to be reduced to a thin form. Therefore, whether for digital or power lithium-ion batteries, slimming down has become a trend while ensuring safety.
3.2 The coating technology application is widely used.
The downstream applications of lithium-ion battery separators are the same as those of lithium-ion batteries, which can be divided into three categories: separators for electronic products, separators for electric transportation, and separators for energy storage and industrial applications. With the explosive growth in demand for power lithium-ion batteries, the demand for separators used in power lithium-ion batteries has surged. According to GGII research, the current lithium-ion battery separator route, primarily consisting of ceramic and PVDF separators, is gradually extending from high-end digital consumer electronics batteries to power batteries such as electric vehicles. Coating has become an important method to enhance the safety of power batteries. Particularly during the rise of ternary batteries, coated separators are expected to gain market favor and capture a larger market share.
Coating refers to applying adhesives such as PVDF or ceramic alumina on the base film. After the alumina coating treatment on the battery separator, the heat shrinkage resistance of the separator is improved, preventing large-scale short circuits caused by shrinkage and simultaneously preventing some thermal runaway points in the battery from expanding into a comprehensive thermal runaway. As early as 2012, coated separators began to gain popularity in high-end digital consumer lithium-ion batteries in China.
3.3 Addressing Lithium Battery Safety: Wet Process + Ceramic Will Be the Best Choice.
Addressing the safety concerns of lithium-ion batteries has become a primary development direction for future separator membranes. Coated separators are a key choice to meet the safety requirements of lithium-ion batteries.
Ceramic diaphragms are coatings of nano-sized ceramic particles on the diaphragm. Their primary function is to enhance the diaphragm's resistance to thermal shrinkage, preventing large-scale short circuits caused by shrinkage. Additionally, ceramic has a low thermal conductivity, which prevents some thermal runaway points within the battery from expanding into a full-scale thermal runaway. They generally withstand temperatures around 200°C.
The drawbacks of lithium-ion battery separators mainly focus on their low melting point and poor thermal resistance. In recent years, with the maturation of coating technology, separators produced by dry or wet processes, when coated with inorganic materials such as alumina and bauxite, can maintain the integrity of the separator even after large-scale heat release during the charging and discharging process. This effectively addresses the issue of poor thermal resistance. Lithium-ion battery separators coated with alumina inorganic materials will significantly enhance the safety performance of lithium-ion batteries, expand their application areas, and gradually enter the mid-to-high-end market, including for power lithium-ion batteries.
