Separator and nonaqueous electrolyte battery, and battery pack, electronic apparatus, electric vehicle, electric power storage device, and electric power system

1. A separator comprising:

a substrate including a porous film; and

a porous surface layer which is provided on at least one surface of the substrate, wherein the porous surface layer consists essentially of a vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene copolymer,

wherein a porosity of the porous surface layer is 35% or more and less than or equal to 52.4%,

wherein a content of a monomer unit derived from the hexafluoropropylene in the porous surface layer is in a range of 5 to 15 percent by mole in the copolymer, a content of a monomer unit derived from the tetrafluoroethylene in the porous surface layer is in a range of 10 to 40 percent by mole in the copolymer, and a content of the monomer unit derived from the vinylidene fluoride in the porous surface layer is in a range of 45 to 85 percent by mole in the copolymer, and

wherein a thickness of the porous surface layer is 1.0 μm to 2.1 μm.

2. The separator according to claim 1 ,

wherein the porous film is a film which contains a resin material and which is drawn in a uniaxial direction.

3. The separator according to claim 1 ,

wherein the porous surface layer has a fibrillated three-dimensional network structure.

4. The separator according to claim 1 ,

wherein the porosity of the porous surface layer is higher than a porosity of the substrate.

5. The separator according to claim 1 , wherein the porosity of the substrate ranges from 35% to 50%.

6. A nonaqueous electrolyte battery comprising:

a positive electrode;

a negative electrode;

a nonaqueous electrolyte; and

at least one separator,

wherein the separator comprises:

a substrate including a porous film; and

a porous surface layer which is provided on at least one surface of the substrate, wherein the porous surface layer consists essentially of a vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene copolymer, and

wherein a porosity of the porous surface layer is 35% or more and 52.4% or less,

wherein a content of a monomer unit derived from the hexafluoropropylene in the porous surface layer is in a range of 5 to 15 percent by mole in the copolymer, a content of a monomer unit derived from the tetrafluoroethylene in the porous surface layer is in a range of 10 to 40 percent by mole in the copolymer, and a content of the monomer unit derived from the vinylidene fluoride in the porous surface layer is in a range of 45 to 85 percent by mole in the copolymer, and

wherein a thickness of the porous surface layer is 1.0 μm to 2.1 μm.

7. The nonaqueous electrolyte battery according to claim 6 ,

wherein the positive electrode and the negative electrode are laminated and wound with the at least one separator provided therebetween to form a wound electrode body.

8. A battery pack comprising:

the nonaqueous electrolyte battery according to claim 6 ;

a control section controlling the nonaqueous electrolyte battery; and

an exterior package enclosing the nonaqueous electrolyte battery.

9. An electronic apparatus comprising:

the nonaqueous electrolyte battery according to claim 6 ,

wherein the nonaqueous electrolyte battery supplies an electric power.

10. An electric vehicle comprising:

the nonaqueous electrolyte battery according to claim 6 :

a converter converting an electric power supplied therefrom into a driving force of a vehicle; and

a control device which performs information processing relating to vehicle control based on information relating to the nonaqueous electrolyte battery.

11. An electric power storage device comprising:

the nonaqueous electrolyte battery according to claim 6 ,

wherein the electric power storage device supplies an electric power to an electronic apparatus connected to the nonaqueous electrolyte battery.

12. The electric power storage device according to claim 11 ,

further comprising an electric power information control device which transmits and receives a signal to and from another apparatus through a network,

wherein based on information received by the electric power information control device, the electric power storage device performs charge/discharge control of the nonaqueous electrolyte battery.

13. An electric power system comprising:

the nonaqueous electrolyte battery according to claim 6 ,

wherein the nonaqueous electrolyte battery supplies an electric power or receives an electric power from a power generator or a power network.