In lithium-ion battery materials, positive and negative electrode materials and electrolytes have been largely domestically produced, while separators started later, and domestic companies' technology maturity is not high. Although the localization rate of lithium-ion battery separators in my country has been increasing in recent years, it mainly occupies the low-end 3C battery separator market, while the localization rate of high-end separators is still very low. High-end 3C batteries and power lithium battery separators still rely heavily on imports.
As is well known, the separator is one of the key internal components in the structure of a lithium-ion battery. It must prevent the positive and negative electrodes from contacting each other while ensuring the passage of electrolyte ions. Therefore, the quality of the separator directly affects the battery's capacity, cycle life, and safety performance. A high-quality separator plays an important role in improving the overall performance of the battery.
The separator is currently the high-value-added material with the highest technical barriers among lithium battery materials, accounting for about 15% of the cost of lithium-ion batteries. Its technical difficulties lie in the engineering technology of pore formation, matrix materials, and manufacturing equipment.
The common problem with domestically produced separators is their lack of consistency, manifested primarily in irregular defects, substandard porosity, and uneven thickness, pore size distribution, and other variations. While domestically produced uniaxially stretched PP separators are relatively close to foreign products in terms of porosity and pore size distribution, biaxially stretched PE separators typically have lower porosity and less than ideal pore size distribution compared to foreign products. These issues represent a potential risk of dependence on foreign suppliers, and if not properly addressed, could hinder the healthy development of my country's lithium battery industry.
High-end lithium-ion battery separator technology has a very high barrier to entry, requiring not only huge investments but also a strong R&D and production team, mature process technology, and high-level production lines. It is not something that can be mastered in a short time. However, the US-China trade war and the ZTE and Huawei incidents have sounded the alarm for my country's manufacturing industry. For the entire power lithium battery industry, breaking through the high-end lithium-ion battery separator technology as soon as possible is now imperative.
