Abstract: This polyolefin micro-porous film includes a multilayered structure, wherein the multilayered structure contains a first layer composed of polypropylene resin, a second layer composed of polyethylene resin and provided on the first layer, and a third layer composed of polypropylene resin and provided on the second layer. Furthermore, a thickness of the first layer is thinner than a thickness of the second layer, a thickness of the third layer is thinner than the thickness of the second layer, and in the multilayered structure, a thickness is 16 ?m or less, a porosity is 40 to 70%, and a surface opening ratio is 10 to 30%.

Abstract: A polyolefin micro porous film includes at least one of polyethylene and polypropylene, in which the compressive elastic modulus is 95 MPa or more and 150 MPa or less, the surface roughness (Ra) of a film surface is measured for a front surface and a rear surface, and the average value (Ra(ave)) thereof is 0.01 ?m to 0.30 ?m.

Abstract: This polyolefin micro-porous film includes a multilayered structure, wherein the multilayered structure contains a first layer composed of polypropylene resin, a second layer composed of polyethylene resin and provided on the first layer, and a third layer composed of polypropylene resin and provided on the second layer. Furthermore, a thickness of the first layer is thinner than a thickness of the second layer, a thickness of the third layer is thinner than the thickness of the second layer, and in the multilayered structure, a thickness is 16 ?m or less, a porosity is 40 to 70%, and a surface opening ratio is 10 to 30%.

Abstract: A porous film including a micro porous film in which a fibril diameter arranged in a direction perpendicular to an MD direction is 50 nm or more and 500 nm or less, a pore diameter is 50 nm or more and 200 nm or less, and a surface opening ratio is 5% or more and 40% or less. In the porous film, the micro porous film may include either one or both of a polyethylene resin and a polypropylene resin.

Abstract: A polyolefin micro porous film includes at least one of polyethylene and polypropylene, in which the compressive elastic modulus is 95 MPa or more and 150 MPa or less, the surface roughness (Ra) of a film surface is measured for a front surface and a rear surface, and the average value (Ra(ave)) thereof is 0.01 ?m to 0.30 ?m.

Abstract: Provided are a separator for an energy storage device having an intermediate coating layer between a porous film (I) and a porous film (II), in which the porous film (I) having the intermediate coating layer on one side and the porous film (II) are mechanically stacked and laminated with each other via the intermediate coating layer, and an energy storage device. According to the present invention, it is possible to provide a separator capable of improving discharge characteristics at low temperatures and cycle characteristics at high temperatures and an energy storage device using the same.