The separator also affects the performance of the battery. The porosity and thickness of the separator determine the battery's rate capability and capacity, while the wettability and surface energy of the separator affect the battery's internal resistance and power output. In addition, the thermal stability and flame retardancy of the separator are crucial for the battery's safety, especially in high-temperature environments.
Manufacturing a high-quality separator is a complex process that involves multiple steps, including extrusion, stretching, and surface treatment. The goal is to produce a separator with uniform thickness, pore size, and mechanical strength, as well as high thermal stability and low internal resistance.
Research and development in the field of battery separators are ongoing, with a focus on improving the performance, safety, and sustainability of lithium-ion batteries. For example, researchers are exploring new materials, such as ceramic or glass fibres, that offer higher thermal stability and flame retardancy than traditional polymeric separators. They are also investigating new manufacturing techniques, such as electrospinning and 3D printing, that enable the production of custom-designed separators with tailored properties.