Layered porous film, and non-aqueous electrolyte secondary battery
A laminated porous film includes: a porous base material layer containing polyolefin as a main component; a filler layer containing inorganic particles as a main component; and a resin layer containing, as a main component, resin particles having a median diameter (D50) of greater than 1 μm.
1. A laminated porous film comprising:
a porous base material layer containing polyolefin as a main component;
a filler layer containing inorganic particles as a main component; and
a resin layer containing, as a main component, resin particles having a median diameter (D50) of equal to or greater than 1.5 μm.
2. The laminated porous film as set forth in claim 1 , wherein
less than 40% by volume of resin particles contained in the resin particles is resin particles each having a particle diameter of less than 0.8 μm.
3. The laminated porous film as set forth in claim 1 ,
wherein:
the filler layer is provided on one surface of the porous base material layer; and
the resin layer is provided on the other surface of the porous base material layer.
4. The laminated porous film as set forth in claim 1 ,
wherein:
a ratio of a weight per unit area of the filler layer to a weight per unit area of the porous base material layer is 0.2 to 3.0; and
a ratio of a weight per unit area of the resin layer to a weight per unit area of the porous base material layer is 0.1 to 2.0.
5. The laminated porous film as set forth in claim 1 , wherein
the inorganic particles are at least one selected from the group consisting of alumina, boehmite, silica, and titania.
6. The porous film as set forth in claim 1 , wherein the inorganic particles are α-alumina.
7. The laminated porous film as set forth in claim 1 , wherein the filler layer contains an organic binder.
8. The laminated porous film as set forth in claim 7 , wherein the organic binder is a water-soluble polymer.
9. The laminated porous film as set forth in claim 8 , wherein
the water-soluble polymer is at least one selected from the group consisting of carboxyalkyl cellulose, alkyl cellulose, and hydroxyalkyl cellulose.
10. The laminated porous film as set forth in claim 1 , wherein the resin layer contains an organic binder.
11. The laminated porous film as set forth in claim 10 , wherein the organic binder is a water-insoluble polymer.
12. The laminated porous film as set forth in claim 11 , wherein
the water-insoluble polymer is at least one selected from the group consisting of an ethylene-vinyl acetate copolymer, an ethylene-acrylic acid ester copolymer, a fluorine-based rubber, and a styrene butadiene rubber.
13. A nonaqueous electrolyte secondary battery comprising:
a laminated porous film recited in claim 1 .