SEPARATOR, PROCESS FOR PREPARING THE SAME, LITHIUM ION SECONDARY BATTERY, BATTERY MODULE, BATTERY PACK AND APPARATUS

The present embodiments provide a separator, a process for preparing the same, a lithium ion secondary battery, a battery module, a battery pack and an apparatus. The separator provided by the present application comprises a porous base film and a functional coating disposed on at least one surface of the porous base film, wherein the functional coating comprises polyimide nanosheets, and the polyimide nanosheets are stacked irregularly to form a lamellar loose structure; and a thickness ratio of the functional coating to the porous base film is from 0.1 to 1.0. The present application also provides a process for preparing the separator, and a lithium ion secondary battery and an apparatus comprising the separator.