Battery

1. A battery, comprising:

a positive electrode including a positive electrode active material layer;

a negative electrode; and

a separator at least including a porous film, wherein the positive electrode active material layer comprises halogen element, wherein the porous film has a porosity ε [%] and an air permeability t [sec/100 cc] which satisfy formulae of:

t=a×Ln(ε)−4.02a+100

and

−1.87×10 10 ×S −4.96 ≤a≤− 40

where S[mg/cm 2 ] is an area density of the positive electrode active material layer and Ln is natural logarithm.

2. The battery according to claim 1 , wherein the positive electrode active material layer has an area density less than or equal to 50 mg/cm −2 .

3. The battery according to claim 1 , wherein the positive electrode active material layer comprises lithium nickel composite oxide.

4. The battery according to claim 1 , wherein the positive electrode active material layer comprises lithium nickel cobalt manganese composite oxide.

5. The battery according to claim 3 , wherein the lithium nickel composite oxide is a composite oxide represented by the following formula (1):

Li x Ni y Co z M1 (1-y-z) O b   1)

where M1 represents at least one element selected from the group consisting of boron (B), magnesium (Mg), aluminum (Al), silicon (Si), phosphorus (P), sulfur (S), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), gallium (Ga), germanium (Ge), yttrium (Y), zirconium (Zr), molybdenum (Mo), silver (Ag), barium (Ba), tungsten (W), indium (In), tin (Sn), lead (Pb) and antimony (Sb);

x, y, z and b are values within ranges of 0.8<x≤1.2, 0.5≤y≤1.0, 0≤z≤0.5, y+z≤1 and 1.8≤b≤2.2; and

the corn position of lithium varies depending on the charging and discharging state, and the value of x indicates the value in the fully-discharged state.

6. The battery according to claim 4 , wherein the lithium nickel cobalt manganese composite oxide is a composite oxide represented by the following formula (2):

Li f Ni g Co i Mn (1-g-i-h) M2 h O (2-j)   (2)

where M2 represents at least one element selected from the group consisting of magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), zinc (Zn), zirconium (Zr), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr) and tungsten (W);

f, g, h, j and i are values within ranges of 0.8≤f≤1.2, 0<g≤0.5, 0≤h≤0.5, g+h+i<1, −0.1≤j≤0.2 and 0<i≤0.5; and

the composition of lithium varies depending on the charging and discharging state, and the value of x indicates the value in the fully-discharged state.

7. The battery according to claim 1 , wherein the porous film has at least one main surface, and the separator further includes a surface layer containing particles and a resin, provided on at least one surface of the porous film.

8. The battery according to claim 1 , wherein the porous film is a polyolefin resin film.

9. The battery according to claim 1 , wherein the separator has a thickness of 3 μm or more and 18 μm or less.

10. A battery pack comprising the battery according to claim 1 .

11. An electronic apparatus comprising the battery according to claim 1 .

12. An electric vehicle, comprising:

the battery according to claim 1 ;

a converter configured to receive electricity supply from the battery and convert the electricity into driving force for vehicle; and

a controller configured to process information on vehicle control on the basis of information on the battery.

13. An electrical storage apparatus comprising the battery according to claim 1 .

14. An electricity system, configured to receive electricity supply from the battery according to claim 1 .

15. The battery according to claim 1 , wherein the positive electrode active material layer has an area density more than or equal to 31 mg/cm 2 .

16. The battery according to claim 1 , wherein the positive electrode active material layer has an area density more than or equal to 32 mg/cm 2 .

17. The battery according to claim 1 , wherein the positive electrode active material layer has an area density more than or equal to 33 mg/cm 2 .

18. The battery according to claim 1 , wherein the positive electrode active material layer has an area density more than or equal to 34 mg/cm 2 .

19. The battery according to claim 1 , wherein the positive electrode active material layer has an area density more than or equal to 35 mg/cm 2 .

20. The battery according to claim 1 , wherein the positive electrode active material layer has an area density more than or equal to 37 mg/cm 2 .

21. The battery according to claim 1 , wherein the positive electrode active material layer has an area density more than or equal to 40 mg/cm 2 .

22. The battery according to claim 1 , wherein the positive electrode active material layer has an area density more than or equal to 42 mg/cm 2 mg/cm 2 .

23. The battery according to claim 1 , wherein the positive electrode active material layer has an area density more than or equal to 43 mg/cm 2 .

24. The battery according to claim 1 , wherein the positive electrode active material layer has an area density more than or equal to 45 mg/cm 2 .

25. The battery according to claim 1 , wherein the positive electrode active material layer has an area density more than or equal to 49 mg/cm 2 .