Laminate, non-aqueous electrolyte secondary battery separator including the laminate, and non-aqueous electrolyte secondary battery including the laminate
Provided is a laminate which is capable of ensuring a high level of safety by preventing an internal short circuit due to, for example, breakage of a non-aqueous electrolyte secondary battery while maintaining various performance capabilities of the non-aqueous electrolyte secondary battery. A laminate ( 10 ) includes: a porous film containing polyolefin as a main component; and a porous layer containing fine particles; the porous layer being laminated to at least one side of the porous film, in an electrical conduction test by nail penetration in which test a displacement in a thickness direction of the laminate ( 10 ) during a period from when a dielectric breakdown occurs in the laminate ( 10 ) to when the laminate ( 10 ) is brought into electrical conduction is measured by use of a nail ( 2 ) of N50 specified in JIS A 5508 and under a condition in which the nail ( 2 ) descends at a descending speed of 50 μm/min, the displacement being not less than 20 μm and not more than 200 μm.
1. A laminate comprising:
a porous film containing polyolefin as a main component; and
a porous layer containing inorganic fine particles which have cleavability;
the porous layer being laminated to at least one side of the porous film,
the porous layer containing, per one side thereof, a porous layer component in a component volume weight per unit area of 2 cm 3 /m 2 to 8 cm 3 /m 2 ,
the porous layer having, per one side thereof, a thickness of 0.5 μm to 15 μm, and the porous film has a thickness of 5 μm to 30 μm, and
in an electrical conduction test by nail penetration in which test a displacement in a thickness direction of the laminate during a period from when a dielectric breakdown occurs in the laminate to when the laminate is brought into electrical conduction is measured by use of a nail of N50 specified in JIS A 5508 and under a condition in which the nail descends at a descending speed of 50 μm/min, the displacement being not less than 20 μm and not more than 200 μm.
2. The laminate as set forth in claim 1 , wherein the porous film has a porosity of 30% by volume to 60% by volume.
3. The laminate as set forth in claim 1 , wherein the porous layer further contains a binder resin, and the fine particles are in point contact with the binder resin.
4. The laminate as set forth in claim 1 , wherein the porous film has a weight per unit area of 4 g/m 2 to 20 g/m 2 .
5. The laminate as set forth in claim 1 , wherein the porous layer has, per one side thereof, a weight per unit area of 1 g/m 2 to 20 g/m 2 .
6. A non-aqueous electrolyte secondary battery separator including a laminate recited in claim 1 .
7. A non-aqueous electrolyte secondary battery including a laminate recited in claim 1 .