| abstract |
The porous layer according to the present invention is divided into 32 rectangular parallelepipeds in which one section is 2.3 μm in length, 2.3 μm in width, and the thickness is the thickness of the porous layer itself, and the porosity of each section is measured. The porous layer has a variation rate of the porosity between 32 compartments of 16.0% or less. The separator formed by laminating the porous layer according to the present invention and the porous layer is suitable as a nonaqueous electrolyte secondary battery member having excellent cycle characteristics. |