Abstract: Provided is a nonaqueous electrolyte secondary battery including a porous film containing polyolefin as a main component, the nonaqueous electrolyte secondary battery separator having a parameter X of not more than 20, the parameter X being calculated based on the following equation: X=100×|MD tan ??TD tan ?|/{(MD tan ?+TD tan ?)/2}, where MD tan ? is tan ? in a machine direction of the porous film and TD tan ? is tan ? in a transverse direction of the porous film, MD tan ? and TD tan ? each being obtained by viscoelasticity measurement carried out with respect to the porous film at a frequency of 10 Hz and a temperature of 90° C. the nonaqueous electrolyte secondary battery separator making it possible to reduce an increase in internal resistance which increase is caused by repeated charge and discharge.

Abstract: A nonaqueous electrolyte secondary battery insulating porous layer having which is excellent in heat resistance and oxidation resistance in a battery is realized. A nonaqueous electrolyte secondary battery insulating porous layer includes aromatic polyester containing (A) a unit derived from aromatic hydroxycarboxylic acid, (B) a unit derived from aromatic dicarboxylic acid, (C) a unit derived from aromatic amine, selected from aromatic diamine and aromatic amine containing a hydroxyl group, and (D) a unit derived from aromatic diol, in respective predetermined ratios.

Abstract: The present invention improves productivity of production of a nonaqueous electrolyte secondary battery. A nonaqueous electrolyte secondary battery insulating porous layer in accordance with an embodiment of the present invention is a constituent member of a nonaqueous electrolyte secondary battery laminated separator, includes a thermoplastic resin, has a porosity of 25% to 80%, and has a peeling strength of above 0 N/m to 2.0 N/m when press-bonded to a nonaqueous electrolyte secondary battery electrode at 25° C. through two one-minute 30 kN applications, the nonaqueous electrolyte secondary battery electrode containing an electrode active material, an electrically conductive agent, and a binding agent in a mass fraction of 92:2.7:5.3.

Abstract: The present invention has an object to provide (i) a nonaqueous electrolyte secondary battery separator having excellent ion permeability and (ii) an insulating porous layer by which to achieve the nonaqueous electrolyte secondary battery separator. The insulating porous layer is a nonaqueous electrolyte secondary battery insulating porous layer containing: a resin A; and a resin B, the resin A and the resin B having therebetween a Hansen solubility parameter distance (HSP distance) (Ra) of not more than 10 MPa1/2.

Abstract: Realized is a nonaqueous electrolyte secondary battery coating material which is excellent in storage property, solution sending property, and coating property. The nonaqueous electrolyte secondary battery coating material has a first value and a second value which fall within respective given ranges, the first value being obtained by dividing a viscosity of the nonaqueous electrolyte secondary battery coating material at a shear rate of 0.1 sec?1 by a viscosity of the nonaqueous electrolyte secondary battery coating material at a shear rate of 100 sec?1, the second value being obtained by dividing the viscosity of the nonaqueous electrolyte secondary battery coating material at the shear rate of 0.1 sec?1 by a viscosity of the nonaqueous electrolyte secondary battery coating material at a shear rate of 10,000 sec?1.

Abstract: The present invention provides a nonaqueous electrolyte secondary battery insulating porous layer having an excellent withstand voltage property and an excellent leakage resistance characteristic. The nonaqueous electrolyte secondary battery insulating porous layer having a trabecular structure including voids, which trabecular structure has an anisotropy value of 1.30 to 2.10, the anisotropy value being calculated from a three-dimensional image showing a void part and a solid content part on respective two gradation levels, the three-dimensional image being prepared by analyzing images of cross sections obtained by making observation at intervals of 20 nm in a thickness direction from a surface of the nonaqueous electrolyte secondary battery insulating porous layer with use of a FIB-SEM having a magnification of 6500 times.

Abstract: The present invention provides a nonaqueous electrolyte secondary battery insulating porous layer having an excellent charge resistance characteristic. The nonaqueous electrolyte secondary battery insulating porous layer has a fractal dimension of 2.42 to 2.60, the fractal dimension being calculated from a three-dimensional image showing a void part and a porous layer part on respective two gradation levels, the three-dimensional image being prepared by analyzing images of cross sections obtained by making observation at intervals of 20 nm in a thickness direction from a surface of the nonaqueous electrolyte secondary battery insulating porous layer by FIB-SEM measurement at a magnification of 6500 times.

Abstract: A core prevents or reduces misalignment of a battery separator wound around the core. The core has one or more grooves in the outer peripheral surface thereof. The grooves extend substantially in the width direction of the core. The grooves have a depth of 30 ?m or greater, and the following condition (1) is satisfied: N/D>0.0025 ??(1) where D is the outer circumference in mm of the core and N is the number of the grooves in the outer peripheral surface.

Abstract: To afford a laminated body that is usable as a nonaqueous electrolyte secondary battery separator and that is not easily curled, a laminated body includes: a porous base material containing a polyolefin-based resin as a main component; and a porous layer containing a polyvinylidene fluoride-based resin, the porous base material having a parameter X of not more than 20, the parameter X being calculated in accordance with a particular formula, the polyvinylidene fluoride-based resin containing crystal form ? in an amount of not less than 36 mol % with respect to 100 mol % of a total amount of the crystal form ? and crystal form ? contained in the polyvinylidene fluoride-based resin.

Abstract: Provided is a nonaqueous electrolyte secondary battery including a porous film containing polyolefin as a main component, the nonaqueous electrolyte secondary battery separator having a parameter X of not more than 20, the parameter X being calculated based on the following equation: X=100×|MD tan ??TD tan ?|/{(MD tan ?+TD tan ?)/2}, where MD tan ? is tan ? in a machine direction of the porous film and TD tan ? is tan ? in a transverse direction of the porous film, MD tan ? and TD tan ? each being obtained by viscoelasticity measurement carried out with respect to the porous film at a frequency of 10 Hz and a temperature of 90° C., the nonaqueous electrolyte secondary battery separator making it possible to reduce an increase in internal resistance which increase is caused by repeated charge and discharge.

Abstract: The present invention provides, as a nonaqueous electrolyte secondary battery separator having excellent heat resistance and excellent ion permeability, a nonaqueous electrolyte secondary battery separator which includes a porous layer including: a nitrogen-containing aromatic polymer A; and an aromatic polymer B differing in structural unit from the nitrogen-containing aromatic polymer A.