The manufacturing process of battery separators can be broadly categorized into two methods: wet and dry. The wet process is widely used for manufacturing battery separators, especially polymeric materials. Polymer Solution Preparation: The first step in the wet process involves preparing a polymer solution.
Most battery separators are currently made out of polyolefins, where Coperion’s twin screw extruder systems have gained years of experience. Due to comprehensive engineering know-how, customized screw design and high process reliability Coperion systems ensure excellent quality of the final product.
Located between the anode and cathode of the battery, it prevents physical contact between the electrodes, while the separator facilitates the transfer of ions in the battery. It can affect key properties such as capacity, cycle performance, and charge-discharge current density of lithium batteries.
Methodologies to fabricate battery separators are sorted into two methods: (1) wet method and (2) dry method . The separator prepared by the wet method has interconnected pores through the entire area (Figure 2 a). On the other hand, the separator fabricated by dry method has plenty of slit-like pores (Figure 2 b).
For large-scale commercial production of microporous separators for Li-ion batteries there are two basic manufacturing processes. The so called wet process (with up to 70% oil) and dry process, both covered and distributed by Coperion.
Information is provided on the typical properties of lithium–ion battery separators that are produced using wet process technology. Advances and developments using the wet process approach are explicitly highlighted. A key effort in this regard is the desire to produce progressively thinner separators.