Separator and nonaqueous electrolyte secondary battery

1. A nonaqueous electrolyte secondary battery separator, wherein

the separator is a laminated separator comprising a porous layer and a polyolefin porous film,

when unevenness data of at least one surface of the porous layer of the separator is analyzed,

kurtosis of a data group of heights from a reference level is not less than 5, the kurtosis of the data group indicating a distribution curve sharper than a normal distribution curve when the kurtosis is not less than 0, and the kurtosis that is larger indicating a sharper distribution curve, and

standard deviation of the data group of the heights from the reference level is not more than 12.

2. The separator as set forth in claim 1 , wherein the porous layer contains a nitrogen-containing aromatic resin.

3. The separator as set forth in claim 2 , wherein the nitrogen-containing aromatic resin is an aramid resin.

4. The separator as set forth in claim 1 , wherein a compressive elastic modulus in a thickness direction is not less than 50 MPa.

5. A nonaqueous electrolyte secondary battery member, comprising a positive electrode, a separator recited in claim 1 , and a negative electrode, which are formed in this order.

6. A nonaqueous electrolyte secondary battery, comprising a separator recited in claim 1 .

7. A nonaqueous electrolyte secondary battery, comprising a nonaqueous electrolyte secondary battery member recited in claim 5 .

8. The separator as set forth in claim 1 , wherein the porous layer contains a filler, and wherein the filler consists of an inorganic filler.