Air electrode batteries
View Patent ↗A battery includes an air electrode and an air access passageway that is closed by a non-liquid valve actuable by differential pressure to provide an opening therein to admit air to the battery.
1. A battery comprising an air cathode that consumes oxygen, a zinc anode, and an air access passageway that is closed by a non-liquid valve actuable by differential pressure to provide an opening therein to admit air to the battery, said valve comprising a thin resilient membrane having a thickness of 10 to 200 μm, comprising a slit having a length of 3 mm to 7 mm, normally closing said passageway but being deformable by differential pressure of no more than 2 mbar to provide said opening in said slit.
2. A battery according to claim 1 , wherein said air access passageway is arranged to admit air to an air space in the battery, and wherein said valve is actuable in response to a fall in pressure in said air space relative to air pressure externally of the battery, to open said passageway to admit air to said air space.
3. A battery according to claim 1 , wherein said passageway is covered by said membrane.
4. A battery according to claim 1 , wherein said membrane is mounted with respect to a casing of the battery, said casing comprising said at least one air access passageway.
5. A battery according to claim 4 , wherein said membrane is mounted directly on said casing to close said air access passageway.
6. A battery according to claim 4 , wherein said membrane is mounted on a plate member located with respect to said battery casing.
7. A battery according to claim 1 , wherein said membrane is elastomenc.
8. A battery according to claim 7 , wherein said membrane exhibits zero permanent deformation on recovery from up to 10% deformation.
9. A battery according to claim 1 , wherein said membrane is approximately 100 μm thick.
10. A battery according to claim 1 , wherein said membrane is of a material having a Young's modulus of not greater than 28 MPa.
11. A battery according to claim 10 , wherein said membrane material has a Young's modulus from 1.6 to 1.8 MPa.
12. A battery according to claim 10 , wherein said membrane material has a Young's modulus of not greater than 2 kPa.
13. A battery according to claim 12 , wherein the membrane material has a Young's modulus of approximately 1.6 kPa.
14. A battery according to claim 1 , wherein the membrane is of a material having a resilience of not greater than 50 MPa.
15. A battery according to claim 14 , wherein said membrane material has a resilience not greater than 2 MPa.
16. A battery according to claim 15 , wherein said membrane material has a resilience of approximately 1.1 MPa.
17. A battery according to claim 1 , wherein said membrane has been made by calendaring.
18. A battery according to claim 1 , wherein said membrane is of a material having a Young's modulus from 1.6 to 1.8 MPa and a resilience of approximately 1.1 MPa.
19. A battery according to claim 1 , wherein said membrane comprises a material selected from the group consisting of natural rubber, neoprene, nitrile rubber, polybutadiene, a copolymer of butadiene, polyisoprene, a butyl rubber, and a silicone elastomer.
20. A battery according to claim 1 , wherein said membrane comprises natural rubber or addition-cured vinyl siloxane.
21. A battery according to claim 1 , wherein said slit is a cut made in said membrane without removal of membrane material.
22. A battery according to claim 1 , wherein said slit is rectilinear.
23. A battery according to claim 1 , wherein said slit has a length of 6 mm.
24. A battery according to claim 1 , wherein said slit is located centrally in a position of membrane extending unsupported in said access passageway.
25. A battery according to claim 24 , wherein said unsupported membrane portion is elliptical in shape.
26. A battery according to claim 24 , wherein opposed ends of said slit are each spaced from the edge of said unsupported membrane portion.
27. A battery according to claim 26 , wherein said opposed ends are each spaced from the edge of said unsupported membrane portion by a distance of between 0.5 and 1.0 mm.
28. A battery according to claim 1 , wherein said differential pressure is no more than 0.5 mbar.
29. A battery according to claim 1 , wherein said membrane defines a flap normally closing said passageway.
30. A battery according to claim 1 , the battery comprising a cathode accessible to the air admitted to the battery.
31. A battery according to claim 1 which is a mobile telephone battery.
32. A battery according to claim 1 , which is an air recovery battery.
33. A battery according to claim 1 , wherein the membrane comprises only one slit.
34. A battery according to claim 1 , the battery including a casing that includes the air access passageway, wherein the casing includes only one outer opening for air to enter the air access passageway.
35. A battery according to claim 34 , wherein the slit is centered relative to the outer opening in the casing.
36. A zinc-air battery comprising;
an anode including zinc;
a cathode that consumes oxygen; and
a separator between the anode and the cathode;
wherein the cathode comprises an outer casing including an air passageway; a resilient membrane comprising a slit, normally closing the air passageway but being deformable by differential pressure of no more than 2 mbar to provide an opening in said slit to adjust oxygen during use of the battery, the air membrane having a thickness of 10 to 200 μm and the slot having a length of 3 to 7 mm; an air distribution layer interior to the membrane; and a catalyst layer interior to the air distribution layer.
37. A battery according to claim 36 , wherein the casing includes only one outer opening for air to enter the air access passageway.
38. A battery according to claim 37 , wherein the slit is centered relative to the outer opening in the casing.