Secondary battery and preparation method thereof, and electric device

Abstract

A secondary battery, including a positive electrode sheet, a negative electrode sheet, and a separator. The separator includes a base membrane and a coating arranged on at least one surface of the base membrane; the coating includes a composite polymer and a binder, and the composite polymer includes a first polymer for an inner core layer and a second polymer for a cladding layer arranged on the surface of the inner core layer; the peel strength between the separator and the positive electrode sheet is 1-5 N/m, and the thermal shrinkage rate of the separator in MD and TD directions is less than 5% at 130° C. for 0.5 h.

Dependencies are inferred from the claim text.