LITHIUM ION SECONDARY BATTERY CONTAINING BOTH SIDES-COATED SEPARATOR, WHICH INCREASES THE SAFETY OF BATTERY

摘要

PURPOSE: A lithium ion secondary battery containing a both sides-coated separator is provided, to prevent the leakage of an electrolyte solution by using a separator whose both sides are coated with a polymer electrolyte, thereby improving the safety of a battery. CONSTITUTION: The lithium ion secondary battery is obtained by layering a positive electrode, a separator whose both sides are coated with a polymer electrolyte, a negative electrode and a separator whose both sides are coated with a polymer electrolyte; and winding the layered one. The polymer electrolyte coated on the both sides of the separator comes in contact with the positive electrode and the negative electrode. Preferably the separator has a patterned polymer electrolyte layer. Preferably the heat and the pressure is applied before, during or after winding to improve the adhesive strength between an electrode face and a polymer layer.