Abstract: Provided is a nonaqueous electrolyte secondary battery laminated separator that makes it possible to reduce an increase in alternating-current resistance after compression. A nonaqueous electrolyte secondary battery in accordance with an embodiment includes: a nonaqueous electrolyte secondary battery functional layer; and a polyolefin base material, the nonaqueous electrolyte secondary battery functional layer and the polyolefin base material being formed on top of each other, after the nonaqueous electrolyte secondary battery laminated separator is subjected to pressure application at 20 MPa, the nonaqueous electrolyte secondary battery functional layer having a compressibility of not less than 15%, and the polyolefin base material having a compressibility of not more than 5%.

Abstract: Provided is a nonaqueous electrolyte secondary battery separator that can prevent a decrease in battery characteristics and/or safety caused by a deformation of a separator due to stress resulting from volume expansion of a negative electrode during charge and discharge. The nonaqueous electrolyte secondary battery separator has a maximum value of a second derivative value of not less than 0.15 which has been calculated based on first derivative values obtained at intervals of 0.5 mm of an elongation amount in a range of a value of X of 0 mm to 7.0 mm on a stress-strain curve obtained from a result of a tension test.

Abstract: As a nonaqueous electrolyte secondary battery porous layer which can improve battery performance such as initial charge-discharge efficiency of a nonaqueous electrolyte secondary battery, provided is a nonaqueous electrolyte secondary battery porous layer which contains a resin that has an amide bond and that contains a cyclic component, and in which a contained amount of the cyclic component is not less than 2.0% by weight and not more than 10.0% by weight relative to a total weight of the resin having the amide bond.

Abstract: A nonaqueous electrolyte secondary battery separator is provided in which thickness unevenness caused by wrinkles is reduced. The nonaqueous electrolyte secondary battery separator includes a polyolefin porous film, and when a test piece cut out from the nonaqueous electrolyte secondary battery separator is immersed in propylene carbonate, the test piece exhibits an elongation percentage difference of not more than 0.20%; the elongation percentage difference being a difference between (i) an elongation percentage in a longitudinal direction of the test piece as observed after 30 minutes of immersion in propylene carbonate and (ii) an elongation percentage in the longitudinal direction of the test piece as observed after 24 hours of immersion in propylene carbonate.

Abstract: A lateral surface (12e) of a long separator sheet (12a, 12b) has a value of edge length (R)/longer side length (P) which is less than 1.04. It is therefore possible to provide the long porous separator sheet that is less likely to be torn in processing.

Abstract: A separator that can be used for a secondary battery and a secondary battery including the separator are described. The separator includes a first layer containing a porous polyolefin. A parameter X in the equation below obtained by a viscoelastic measurement at a frequency of 10 Hz and a temperature of 90° C. is equal to or less than 20. The tearing strength of the first layer measured by the Elmendorf tearing method (in accordance with JIS K 7128-2) is at least 1.5 mN/?m, and a tensile elongation value of the first layer is at least 0.5 mm until a load decreases to 25% of a maximum load in a load-elongation curve in a tearing strength measurement by the right-angled tearing method (in accordance with JIS K 7128-3).

Abstract: A nonaqueous electrolyte secondary battery separator is provided in which thickness unevenness caused by wrinkles is reduced. The nonaqueous electrolyte secondary battery separator includes a polyolefin porous film, and when a test piece cut out from the nonaqueous electrolyte secondary battery separator is immersed in propylene carbonate, the test piece exhibits an elongation percentage difference of not more than 0.20%; the elongation percentage difference being a difference between (i) an elongation percentage in a longitudinal direction of the test piece as observed after 30 minutes of immersion in propylene carbonate and (ii) an elongation percentage in the longitudinal direction of the test piece as observed after 24 hours of immersion in propylene carbonate.

Abstract: A nonaqueous electrolyte secondary battery separator having reduced anisotropy of deformation after immersion in an electrolyte is provided. The nonaqueous electrolyte secondary battery separator includes a polyolefin porous film. EMaxB, EMinB, EMax24, and EMin24, which are tensile elastic moduli of the nonaqueous electrolyte secondary battery separator as measured via a specific method, satisfy the following Expression 1: (EMin24/EMinB)/(EMax24/EMaxB)?0.80??Expression 1.

Abstract: A separator and a secondary battery including the separator are described. The separator includes a first layer consisting of porous polyolefin. A temperature-increase convergence time to the amount of a resin in the first layer per unit area is at least 2.9 s·m2/g and equal to or shorter than 5.7 s·m2/g when the layer is irradiated with a microwave (frequency 2455 MHz, output of 1800W) after being impregnated with N-methylpyrrolidone containing 3 wt % of water. The tearing strength of the first layer measured by the Elmendorf tearing method (JIS K 7128-2) is at least 1.5 mN/?m, and a tensile elongation value of the first layer is at least 0.5 mm until a load decreases to 25% of a maximum load from when the load reaches the maximum load in a load-elongation curve in the tearing strength measurement (JIS K 7128-3) by the right-angled tearing method.

Abstract: Provided is a separator including a first layer which consists of a porous polyolefin and a secondary battery utilizing the separator. A first layer exhibits a minimum height equal to or more than 50 cm and equal to or less than 150 cm when a ball having a diameter of 14.3 mm and a weight of 11.9 g located over the first layer is allowed to free fall causing a split in the first layer. A tearing strength of the first layer in a width direction, measured with an Elmendorf tearing method, is equal to or more than 1.5 mN/?m. A tensile elongation of the first layer is equal to or longer than 0.5 mm until a load decreases to 25% of a maximum load in a load-elongation curve in machine direction measured by a rectangular tearing method.

Abstract: A laminated porous film, including: a porous layer containing a polyolefin; and a porous layer containing a heat-resistant material and provided on at least one surface of the porous layer containing the polyolefin, the laminated porous film satisfying Formula (I) below, 0.1136×?+0.0819×?+3.8034?4.40??(I), where ? is a value of a film resistance (?·cm2) of the laminated porous film, and ? is a value of a volume (cc/m2) of the heat-resistant material contained per 1 m2 of the porous layer containing the heat-resistant material.

Abstract: A lateral surface (12e) of a long separator sheet (12a, 12b) has a value of edge length (R)/longer side length (P) which is less than 1.04. It is therefore possible to provide the long porous separator sheet that is less likely to be torn in processing.

Abstract: A long separator sheet (12a?, 12b?) has a right edge part (12c?) that is in a trapezoidal shape and a left edge part (12d?) having a curved shape. Therefore, it is possible to provide a long porous separator sheet which satisfies both a good electrolyte take-in property (i.e., liquid absorption property) and a good electrolyte retaining property (i.e., liquid retention property).

Abstract: A roll is made of a porous film in a belt-like shape, the porous film having a width of not smaller than 20 mm. In a case where a roughness along a width direction of an outermost surface of the roll is measured at 1 mm intervals across an entire width of the outermost surface, a difference between a maximum roughness value and a minimum roughness value in a distance of 20 mm in the width direction of the outermost surface is less than 25 ?m.

Abstract: A roll of an embodiment of the present invention is a roll that is made of a porous film in a belt-like shape, the porous film having a width of not smaller than 20 mm. In a case where a roughness along a width direction of an outermost surface of the roll is measured at 1 mm intervals across an entire width of the outermost surface, a difference between a maximum roughness value and a minimum roughness value in a distance of 20 mm in the width direction of the outermost surface is less than 25 ?m.

Abstract: Provided is a nonaqueous electrolyte secondary battery separator which allows occurrence of an internal short circuit to sufficiently suppressed and accordingly allows a battery to be greatly safe, the nonaqueous electrolyte secondary battery separator including a porous film containing a polyolefin-based resin as a main component, the nonaqueous electrolyte secondary battery separator having tear strength of not less than 1.5 mN/?m, the tear strength being measured by the Elmendorf tear method, the nonaqueous electrolyte secondary battery separator exhibiting tensile elongation of a value A of not less than 0.5 mm from a time point when a load reaches a maximum load to a time point when the load decreases to 25% of the maximum load, according to a load-tensile elongation curve based on the right angled tear method.

Abstract: A laminated porous film, including: a porous layer containing a polyolefin; and a porous layer containing a heat-resistant material and provided on at least one surface of the porous layer containing the polyolefin, the laminated porous film satisfying Formula (I) below, 0.1136×?+0.0819×?+3.8034?4.40 ??(I), where ? is a value of a film resistance (?·cm2) of the laminated porous film, and ? is a value of a volume (cc/m2) of the heat-resistant material contained per 1 m2 of the porous layer containing the heat-resistant material.

Abstract: Disclosed is a sodium-ion secondary battery having excellent charge and discharge efficiencies as well as excellent charge and discharge characteristics, wherein charging and discharging can be repeated without causing problems such as deterioration in battery performance. Specifically disclosed is a sodium ion secondary battery which is provided with a positive electrode, a negative electrode having a negative electrode active material, and a nonaqueous electrolyte solution containing a nonaqueous solvent. The nonaqueous solvent is substantially composed of a saturated cyclic carbonate (excluding the use of ethylene carbonate by itself), or a mixed solvent of a saturated cyclic carbonate and a chain carbonate, and a hard carbon is used as the negative electrode active material.

Abstract: Disclosed is a sodium-ion secondary battery having excellent charge and discharge efficiencies as well as excellent charge and discharge characteristics, wherein charging and discharging can be repeated without causing problems such as deterioration in battery performance. Specifically disclosed is a sodium ion secondary battery which is provided with a positive electrode, a negative electrode having a negative electrode active material, and a nonaqueous electrolyte solution containing a nonaqueous solvent. The nonaqueous solvent is substantially composed of a saturated cyclic carbonate (excluding the use of ethylene carbonate by itself), or a mixed solvent of a saturated cyclic carbonate and a chain carbonate, and a hard carbon is used as the negative electrode active material.