Batteries including improved fine fiber separators

1. A battery having a separator comprising a porous fine fiber layer of polymeric fibers having a mean diameter in the range from about 50 nm to about 3000 nm, wherein the porous fine fiber layer has a mean flow pore size of between about 0.01 μm and about 15 μm, a thickness of between about 0.1 mils (0.0025 mm) and about 12 mils (0.3 mm), a porosity of between about 20% and about 90%, a basis weight of between about 1 g/m 2 and about 90 g/m 2 , a Frazier air permeability of less than about 150 cfm/ft 2 (46 m 3 /min/m 2 ) and a MacMullin number of between about 2 and about 15.

2. The battery of claim 1 wherein the porous fine fiber layer has a Frazier air permeability of less than about 25 cfm/ft 2 (8 m 3 /min/m 2 ).

3. The battery of claim 1 wherein the fibers comprise a polymer selected from the group consisting of aliphatic polyamide, semi-aromatic polyamide, polyvinyl alcohol, cellulose, polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polysulfone, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropene, polymethyl pentene, polyacrylonitrile, polymethyl methacrylate, polyphenylene sulfide, polyacetyl, polyurethane, aromatic polyamide and blends, mixtures and copolymers thereof.

4. The battery of claim 1 wherein the porous fine fiber layer has a mean flow pore size of between about 0.01 μm and about 5 μm.

5. The battery of claim 1 wherein the porous fine fiber layer has a thickness of between about 0.5 mil (0.0127 mm) and about 5 mil (0.127 mm).

6. The battery of claim 1 wherein the porous fine fiber layer has a basis weight of between about 5 g/m 2 and about 30 g/m 2 .

7. The battery of claim 1 wherein the fibers have a mean diameter between about 50 nm and about 1000 nm.

8. The battery of claim 3 wherein the polymer is crosslinked.

9. The battery of claim 1 wherein the porous fine fiber layer has an ionic resistance of between about 10 milliohms-cm 2 and about 60 milliohms-cm 2 in 40% potassium hydroxide electrolyte solution.

10. The battery of claim 1 wherein the porous fine fiber layer has an ionic resistance of between about 1 ohms-cm 2 and about 5 ohms-cm 2 in 0.5 molar lithium trifluoromethanesulfonate (LiTFS), propylene carbonate:ethylene carbonate:dimethoxyethane (22:8:70) electrolyte solution.

11. The battery of claim 1 wherein the separator comprises multiple porous fine fiber layers.

12. The battery of claim 11 wherein the separator comprises multiple porous fine fiber layers comprising differing polymers.

13. The battery of claim 11 wherein the separator comprises multiple porous fine fiber layers having differing characteristics selected from the list consisting of thickness, basis weight, pore size, fiber size, porosity, air permeability, ionic resistance and tensile strength.

14. The battery of claim 1 which is an alkaline battery.

15. The alkaline battery of claim 14 wherein the battery separator has an ionic resistance of less than about 100 milliohms-cm 2 in 40% potassium hydroxide electrolyte solution.

16. The alkaline battery of claim 14 wherein the battery separator has a MacMullin number of between about 2 and about 6 and an ionic resistance of between about 10 milliohms-cm 2 and about 60 milliohms-cm 2 in 40% potassium hydroxide electrolyte solution.

17. The alkaline battery of claim 14 wherein the fibers are formed of a polymer selected from the list consisting of aliphatic polyamide, semi-aromatic polyamide, polyvinyl alcohol, cellulose, polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polysulfone, polyvinylidene fluoride, polymethyl pentene, polyphenylene sulfide, polyacetyl, polyurethane, aromatic polyamide and blends, mixtures and copolymers thereof.

18. The alkaline battery of claim 14 wherein the alkaline battery is a Zn—MnO 2 primary, Zn—MnO 2 secondary, Zn-Air, Zn—AgO, Ni—Zn, Cd-AgO, Zn—HgO, Cd—HgO Ni—Cd, Ni-Metal Hydride, or N 1 —H 2 battery.

19. A lithium battery having a separator comprising a porous nanofiber layer of polymeric fibers having a mean diameter in the range from about 50 nm to about 1000 nm, wherein the nanofiber layer has a mean flow pore size of between about 0.01 μm and about 10 μm, a thickness of between about 0.1 mils (0.0025 mm) and about 5 mils (0.127 mm), a basis weight of between about 1 g/m 2 and about 30 g/m 2 , a porosity of between about 20% and about 90%, a Frazier air permeability of less than about 50 cfm/ft 2 (15 m 3 /min/m 2 ) and a MacMullin number of between about 2 and about 15.

20. The lithium battery of claim 19 wherein the battery separator has an ionic resistance of less than about 10 ohms-cm 2 in 0.5 molar lithium trifluoromethanesulfonate (LiTFS), propylene carbonate: ethylene carbonate: dimethoxyethane (22:8:70) electrolyte solution.

21. The lithium battery of claim 19 wherein the battery separator has a MacMullin number of between about 4 and about 10 and an ionic resistance of between about 1 ohms-cm 2 and about 5 ohms-cm 2 in 0.5 molar lithium trifluoromethanesulfonate (LiTFS), propylene carbonate:ethylene carbonate:dimethoxyethane (22:8:70) electrolyte solution.

22. The lithium battery of claim 19 wherein the fibers are formed of a polymer selected from the list consisting of aliphatic polyamide, semi-aromatic polyamide, polyacrylonitrile, polyvinyl alcohol, polypropylene, polyethylene, polyethylene terephthalate, polybutylene terephthalate, polypropylene terephthalate, polysulfone, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropene, polymethyl pentene, polyphenylene sulfide, polytetrafluoroethylene, ethylene tetrafluoroethylene, polyacetyl, polyurethane, aromatic polyamide and blends, mixtures and copolymers thereof.

23. The lithium battery of claim 19 wherein the lithium battery is a lithium primary, lithium ion secondary or lithium ion gel polymer battery.

24. The lithium battery of claim 19 wherein the lithium battery is a Li—MnO 2 or Li—FeS 2 lithium primary battery.

25. The lithium battery of claim 22 wherein the polymer is crosslinked.