NOVELTY - A battery-cell separator is obtained by laminating a reformation porous layer on the single surface of a polyolefin microporous film. The reformation porous layer contains water-soluble resin or water-dispersible resin, and microparticles. The polyolefin microporous film contains a polyethylene-type resin. The polyolefin microporous film has a shutdown temperature of 135 degrees C or less, a gas permeability resistance change rate of 1x 104 seconds/100cc/ degrees C or more, and a shrinkage percentage of 20% or less. The thickness of the polyolefin microporous film is 16 mu m or less.    USE - Battery-cell separator is used for non-aqueous electrolyte battery e.g. lithium-ion secondary battery used for power supply of electric vehicle, and portable electronic devices e.g. notebook personal computer and mobile telephone.    ADVANTAGE - The battery-cell separator has excellent shutdown characteristics, strength, heat resistance, electrolyte-solution permeability, and adhesiveness with respect to the electrode material.    DETAILED DESCRIPTION - A battery-cell separator is obtained by laminating a reformation porous layer on the single surface of a polyolefin microporous film. The reformation porous layer contains water-soluble resin or water-dispersible resin, and microparticles. The polyolefin microporous film contains a polyethylene-type resin. The polyolefin microporous film has a shutdown temperature of 135 degrees C or less, a gas permeability resistance change rate of 1x 104 seconds/100cc/ degrees C or more, and a shrinkage percentage of 20% or less at 130 degrees C. The shutdown temperature is a temperature at which the gas permeability resistance measured by heating the microporous film at a temperature increase rate of 5 degrees C/minutes reaches 1x 105 seconds/100cc. The gas permeability resistance change rate is a gradient in the gas permeability resistance of 1x 104 seconds/100cc with respect to temperature of the gas permeability resistance. The shrinkage percentage is measured by thermomechanical analysis using a load of 2 gf at temperature increase rate of 5 degrees C/minutes in a horizontal direction. The thickness of the polyolefin microporous film is 16 mu m or less. The difference between the shutdown temperatures of the polyolefin microporous film and a laminated polyolefin microporous film is 4 degrees C or less. An INDEPENDENT CLAIM is included for manufacture of battery-cell separator.