Biaxial Stretching Production Line for Lithium-Ion Battery Separators

The primary function of a lithium‑battery separator is to electrically isolate the positive and negative electrodes, preventing direct contact and short circuits. The micropores in the separator allow lithium ions to pass through, thereby enabling the charge–discharge circuit. As a core, critical component of lithium batteries, the separator also represents a high‑value material with significant technological barriers. Its performance directly influences the battery’s interfacial structure, internal resistance, capacity, cycle life, and safety characteristics.

In the structure of a lithium battery, the separator is one of the key internal components. Its performance determines the battery’s interfacial structure and internal resistance, directly influencing critical characteristics such as capacity, cycle life, and safety. A high‑performance separator plays a vital role in enhancing the battery’s overall performance. Simply put, the separator is a porous plastic film; it is a high‑value‑added material with significant technological barriers, accounting for roughly 20% to 30% of the total cost of a lithium battery.
Jinwei’er Machinery specializes in manufacturing dry- and wet‑process biaxial‑stretching extrusion lines for PP/PE lithium‑ion battery separators. These lines are equipped with our newly developed MDO (machine‑direction orientation) and TDO (transverse‑direction orientation) units, enabling stable, uniform stretching of the finished product and significantly reducing the defect rate.

Lithium‑battery separator production lines are categorized as follows: dry‑process unidirectional stretching lines, dry‑process biaxial stretching lines, and wet‑process biaxial stretching lines.

Application scope: Large‑scale lithium‑ion power batteries (for electric vehicles, electric motorcycles, power tools, large‑scale energy storage systems, and military‑grade high‑capacity batteries)

Wet‑process biaxial stretching production line: Applications include high‑performance lithium‑ion batteries, among others.

Product Features: Lithium-ion battery separators are polymeric functional materials with nanoscale micropores. Rechargeable lithium-ion batteries exhibit high specific energy, long cycle life, and no memory effect, while also offering safety, reliability, and rapid charge–discharge capabilities. These attributes align with the growing global demand for energy efficiency and environmental sustainability, leading to a rapid increase in their adoption across various industries. Separators produced via biaxial stretching offer superior safety compared to uniaxially stretched counterparts, with enhanced thermal stability and current‑blocking performance, high ionic conductivity, excellent high‑current charge–discharge characteristics, and extended service life—making them well suited for manufacturing high‑capacity lithium-ion batteries, such as those used in power‑train applications.
1. Excellent thickness uniformity and uniform micropore distribution, which contribute to the consistency of lithium-ion batteries.
2. Low micropore tortuosity, excellent air permeability, strong liquid‑retention capability, and low internal resistance.
3. High-temperature resistant, with no lateral thermal shrinkage, a high film‑bursting temperature, and excellent safety performance;
4. High tensile strength and excellent mechanical properties;
5. The standard width of the production line ranges from 1,000 to 2,400 mm; specific dimensions are determined by the manufacturing process and can be customized.

Main applications: power lithium-ion batteries for electric vehicles, electric motorcycles, electric bicycles, power tools, and other systems; large-scale energy storage lithium-ion batteries; and various types of consumer‑grade lithium-ion batteries.

Lithium‑ion battery separator biaxial stretching production line parameters (for details, please consult a sales engineer)