Separator for nonaqueous secondary battery, and nonaqueous secondary battery
An object of the invention is to provide a separator for a nonaqueous secondary battery, which has good adhesion to electrodes and is also capable of ensuring sufficient ion permeability even after attachment to electrodes. The separator for a nonaqueous secondary battery of the invention includes a porous substrate and an adhesive porous layer that is formed on at least one side of the porous substrate and contains a polyvinylidene-fluoride-based resin. The separator for a nonaqueous secondary battery is characterized in that the adhesive porous layer has a crystal size of 1 to 13 nm.
1. A separator for a nonaqueous secondary battery, comprising a porous substrate and an adhesive porous layer that is formed on at least one side of the porous substrate and contains a polyvinylidene-fluoride-based resin,
the separator for a nonaqueous secondary battery being characterized in that the adhesive porous layer has a crystal size of 1 nm or more and 13 nm or less.
2. The separator for a nonaqueous secondary battery according to claim 1 , characterized in that the weight of the adhesive porous layer formed on one side of the porous substrate is 0.5 g/m 2 or more and 1.5 g/m 2 or less.
3. The separator for a nonaqueous secondary battery according to claim 2 , characterized in that the adhesive porous layer is formed on both front and back sides of the porous substrate.
4. The separator for a nonaqueous secondary battery according to claim 1 , characterized in that the adhesive porous layer is formed on both front and back sides of the porous substrate.
5. The separator for a nonaqueous secondary battery according to claim 4 , characterized in that the total weight of the adhesive porous layers formed on both sides of the porous substrate is 1.0 g/m 2 or more and 3.0 g/m 2 or less, and the difference between the weight of the adhesive porous layer on one side and the weight of the adhesive porous layer on the other side is from 0 to 20% of the total weight.
6. The separator for a nonaqueous secondary battery according to claim 1 , characterized in that the value obtained by subtracting the Gurley value of the porous substrate from the Gurley value of the separator for a nonaqueous secondary battery with the adhesive porous layer formed thereon is from 0 to 300 sec/100 cc.
7. The separator for a nonaqueous secondary battery according to claim 1 , characterized in that the porous substrate is a polyolefin microporous membrane containing polyethylene.
8. The separator for a nonaqueous secondary battery according to claim 1 , characterized in that the porous substrate is a polyolefin microporous membrane containing polyethylene and polypropylene.
9. The separator for a nonaqueous secondary battery according to claim 8 , characterized in that the polyolefin microporous membrane includes at least two layers with one of the two layers containing polyethylene and the other layer containing polypropylene.
10. A nonaqueous secondary battery comprising the separator according to claim 1 .