MULTI-LAYERED SEPARATOR FILM OF LITHIUM SECONDARY BATTERY USING FUNCTIONAL POLYMER AND METHOD OF PREPARATION THE SAME

摘要

PURPOSE: A multi-layered separation film for a lithium secondary battery which uses a functional polymer and a manufacturing method thereof are provided to have a low thermal shrinkage ratio, improved fire retardant, thereby having excellent thermal stability. CONSTITUTION: A multi-layered separation film for a lithium secondary battery includes a polymer of a polyolefin system, a compound which is represented by chemical formula 1 as below. The separation film comprises a first layer, a second layer, and a third layer. The third layer exists in between the first layer and the second layer. The first and the second layer are a compound layer which is represented by the chemical formula 1, or a polymer which is coated with the compound which is represented by the chemical formula 1. The polymer layer of the polyolefin system is composed of polyethylene or polypropylene.