Abstract: A nonaqueous electrolyte secondary battery separator has a short circuit prevention effect improved by controlling the shape of a dendrite. In the nonaqueous electrolyte secondary battery separator, when unevenness data of at least one surface of the separator is analyzed, kurtosis of a data group of heights from a reference level is not less than 5, and standard deviation of the data group of the heights from the reference level is not more than 12.

Abstract: A nonaqueous electrolyte secondary battery laminate is provided which has a short circuit prevention effect improved by controlling the shape of a dendrite. The nonaqueous electrolyte secondary battery laminate in accordance with an aspect of the disclosure includes a separator and a graphite negative electrode. The graphite negative electrode has a non-reactivity parameter of not less than 230%. The separator has a surface that faces the graphite negative electrode and has an average void volume, obtained by analyzing a microscopic image of the surface, of not more than 0.015 ?m3.

Abstract: A nonaqueous electrolyte secondary battery separator has a short circuit prevention effect improved by controlling the shape of a dendrite. The nonaqueous electrolyte secondary battery separator is configured such that, in any area measuring 1.5 cm by 1.5 cm on at least one surface of the separator, a coefficient of variation of an ionic resistance is not more than 0.20. The coefficient of variation of the ionic resistance is calculated from local ionic resistances at 10 points which are measured at 800 ?m intervals with use of probes each measuring 7 mm in length by 250 ?m in width.

Abstract: The present invention provides, as a separator having both a sufficient level of safety and sufficient strength, a nonaqueous electrolyte secondary battery separator including a polyolefin porous film, the nonaqueous electrolyte secondary battery separator being arranged such that in regard to a surface of the nonaqueous electrolyte secondary battery separator, a product obtained by multiplying (a) a difference between a surface roughness in a machine direction obtained by a contact measurement and a surface roughness in the machine direction obtained by a non-contact measurement by (b) a difference between a surface roughness in a transverse direction obtained by a contact measurement and a surface roughness in the transverse direction obtained by a non-contact measurement is not less than 0.0020 and not more than 0.0280.

Abstract: The present invention provides, as a separator having both a sufficient level of safety and sufficient strength, a nonaqueous electrolyte secondary battery separator including a polyolefin porous film, the nonaqueous electrolyte secondary battery separator being arranged such that in regard to a surface of the nonaqueous electrolyte secondary battery separator, a product obtained by multiplying (a) a difference between a surface roughness in a machine direction obtained by a contact measurement and a surface roughness in the machine direction obtained by a non-contact measurement by (b) a difference between a surface roughness in a transverse direction obtained by a contact measurement and a surface roughness in the transverse direction obtained by a non-contact measurement is not less than 0.0020 and not more than 0.0280.

Abstract: The present invention provides, as a separator having both a sufficient level of safety and sufficient strength, a nonaqueous electrolyte secondary battery separator including a polyolefin porous film, the nonaqueous electrolyte secondary battery separator being arranged such that in regard to a surface of the nonaqueous electrolyte secondary battery separator, a product obtained by multiplying (a) a difference between a surface roughness in a machine direction obtained by a contact measurement and a surface roughness in the machine direction obtained by a non-contact measurement by (b) a difference between a surface roughness in a transverse direction obtained by a contact measurement and a surface roughness in the transverse direction obtained by a non-contact measurement is not less than 0.0020 and not more than 0.0280.