NOVELTY - The planar substrate comprises a porous coating layer comprising a polymeric binder and inorganic particles that are longitudinally spaced apart from each other. The porous coating layer is coated with a successive pattern or discontinuous pattern. The porous coating layer coated with the discontinuous pattern is in the form of polygon, circle or ellipse. A thickness of the porous coating layer is 0.01-50 mu m. A width of a gas flow path is 1-1000 mu m. The inorganic particles have a permittivity constant of greater than or equal to 5 or a lithium ion transfer capability.    USE - The planar substrate is useful for an electrochemical device such as a lithium secondary battery (all claimed), which is useful in an electric vehicle, a cellular phone, a camcorder and a notebook computer.    ADVANTAGE - The planar substrate has improved gas discharge property, improves mechanical property, ion conductivity, safety and performance of the electrochemical device, and prevents the generation of thermal shrinkage and internal short-circuit in the anode and the cathode.    DETAILED DESCRIPTION - The planar substrate comprises a porous coating layer comprising a polymeric binder and inorganic particles that are longitudinally spaced apart from each other. The porous coating layer is coated with a successive pattern or discontinuous pattern. The porous coating layer coated with the discontinuous pattern is in the form of polygon, circle or ellipse. A thickness of the porous coating layer is 0.01-50 mu m. A width of a gas flow path is 1-1000 mu m. The inorganic particles have a permittivity constant of greater than or equal to 5 or a lithium ion transfer capability. The substrate comprises a separator, a cathode or an anode. The cathode comprises a cathode active substance layer formed in a side of a cathode current collector. The anode comprises an anode active material layer formed in a side of an anode collector. An INDEPENDENT CLAIM is included for a method for manufacturing the substrate.