Battery separator, method of manufacturing a battery separator, battery, battery pack, and electronic apparatus

1. A battery separator, comprising:

a porous base material including

a first surface,

a second surface opposed to the first surface, and

a hole that is formed in the porous base material and causes the first surface and the second surface to communicate with each other, the hole having an inner diameter of 50 nm or more and 100 nm or less; and

a heat-resistant layer configured to cover at least the first surface and inner pore surfaces of the hole between the first surface and the second surface, the heat-resistant layer being formed of an inorganic material and deposited by an atomic layer deposition method,

wherein the heat-resistant layer has a thickness of 2 nm or more and 10 nm or less such that the covered hole has a covered inner diameter of 30 nm or more and 96 nm or less, and an air resistance of the separator is about 420 s/100 m or less.

2. The battery separator according to claim 1 , wherein

the heat-resistant layer covers the first surface, the second surface, and the surface of the hole.

3. The battery separator according to claim 1 , wherein

the inorganic material is any one of an aluminum oxide, a silicon oxide, and a titanium oxide.

4. The battery separator according to claim 1 , wherein

the base material is a polyolefin-based resin.

5. The battery separator according to claim 1 , wherein

the base material has a thickness of 5 μm or more and 20 μm or less.

6. A method of manufacturing a battery separator, comprising:

preparing a porous base material including

a first surface,

a second surface opposed to the first surface, and

a hole that is formed in the porous base material and causes the first surface and the second surface to communicate with each other, the hole having an inner diameter of 50 nm or more and 100 nm or less; and

forming a heat-resistant layer by an atomic layer deposition method, the heat-resistant layer being configured to cover at least the first surface and inner pore surfaces of the hole between the first surface and the second surface, the heat-resistant layer being formed of an inorganic material,

wherein the heat-resistant layer has a thickness of 2 nm or more and 10 nm or less such that the covered hole has a covered inner diameter of 30 nm or more and 96 nm or less, and an air resistance of the separator is about 420 s/100 m or less.

7. The method of manufacturing a battery separator according to claim 6 , wherein

the heat-resistant layer is alternately formed on the first surface and the second surface.

8. A battery, comprising:

a positive electrode;

a negative electrode;

an electrolyte layer arranged between the positive electrode and the negative electrode; and

a separator including

a porous base material including a first surface opposed to the positive electrode, a second surface opposed to the negative electrode, and a hole that is formed in the porous base material and causes the first surface and the second surface to communicate with each other, the hole having an inner diameter of 50 nm or more and 100 nm or less, and

a heat-resistant layer to cover at least the first surface and inner pore surfaces of the hole between the first surface and the second surface, the heat-resistant layer being formed of an inorganic material and deposited by an atomic layer deposition method,

wherein the heat-resistant layer has a thickness of 2 nm or more and 10 nm or less such that the covered hole has a covered inner diameter of 30 nm or more and 96 nm or less, and an air resistance of the separator is about 420 s/100 m or less.

9. A battery pack, comprising:

a battery including

a positive electrode,

a negative electrode,

an electrolyte layer arranged between the positive electrode and the negative electrode, and

a separator including

a porous base material including a first surface opposed to the positive electrode, a second surface opposed to the negative electrode, and a hole that is formed in the porous base material and causes the first surface and the second surface to communicate with each other, the hole having an inner diameter of 50 nm or more and 100 nm or less, and

a heat-resistant layer to cover at least the first surface and inner pore surfaces of the hole between the first surface and the second surface, the heat-resistant layer being formed of an inorganic material and deposited by an atomic layer deposition method;

a control unit configured to control charge and discharge of the battery; and

a package body configured to support the battery and the control unit,

wherein the heat-resistant layer has a thickness of 2 nm or more and 10 nm or less such that the covered hole has a covered inner diameter of 30 nm or more and 96 nm or less, and an air resistance of the separator is about 420 s/100 m or less.

10. An electronic apparatus, comprising:

a battery including

a positive electrode,

a negative electrode,

an electrolyte layer arranged between the positive electrode and the negative electrode, and

a separator including

a porous base material including a first surface opposed to the positive electrode, a second surface opposed to the negative electrode, and a hole that is formed in the porous base material and causes the first surface and the second surface to communicate with each other, the hole having an inner diameter of 50 nm or more and 100 nm or less, and

a heat-resistant layer to cover at least the first surface and inner pore surfaces of the hole between the first surface and the second surface, the heat-resistant layer being formed of an inorganic material and deposited by an atomic layer deposition method; and

a power receiving circuit configured to receive power supply from the battery,

wherein the heat-resistant layer has a thickness of 2 nm or more and 10 nm or less such that the covered hole has a covered inner diameter of 30 nm or more and 96 nm or less, and an air resistance of the separator is about 420 s/100 m or less.