The present invention provide a separator for an electrochemical device which
comprises a wet nonwoven fabric comprising one or more kinds of fibrillated organic
fibers which are at least partially fibrillated into a fiber diameter of 1 m
or less, and one or more kinds of unfibrillated organic fibers having a fineness
of 0.5 dtex or less, which exhibits excellent heat resistance, electrolyte holding
properties, internal short-circuit preventing property, and winding property, which
results in a lowered internal resistance and prolonged life of an electrochemical
device, and a method for producing the same and an electrochemical device.
