Because of the constantly increasing demand for highly safe lithium-ion batteries (LIBs), interest in the development of ceramic composite separators (CCSs) is growing rapidly. Here, an in-depth study of the adhesion properties of the Al2O3 ceramic composite coating layer of CCSs is conducted using a peel test and a surface and interfacial cutting analysis system (SAICAS). Contrary to the 90 and 180° peel tests, which resulted in different adhesion strengths even for the same CCS sample, the SAICAS is able to measure the adhesion properties uniformly as a function of depth from the surface of the coating layer. The adhesion strengths measured at the midlayer (Fmid) and interface (Finter, interlayer between the separator and the ceramic coating layer) are compared for various types of CCS samples with different amounts of polymeric binder, and it is found that Finter is higher than Fmid for all CCSs. Compared with Fmid, Finter is significantly affected by storage in the liquid electrolyte (under wet condition).