Housing for a sealed electrochemical battery cell
View Patent ↗An electrochemical cell with a collector assembly for sealing the open end of a cell container. The collector assembly includes a retainer and a contact spring with a peripheral flange, each having a central opening therein. A pressure release vent member disposed between the retainer and the peripheral flange of the contact spring seals the openings in the retainer and contact spring under normal conditions and ruptures to release pressure from within the cell when the internal pressure exceeds a predetermined limit.
1. An electrochemical battery cell comprising a housing, an electrode assembly comprising a positive electrode, a negative electrode and a separator disposed between the electrodes, and an electrolyte, the housing comprising:
a container with an open end in which the electrode assembly and electrolyte are disposed; and
a collector assembly, disposed between the electrode assembly and the open end of housing, the collector assembly having:
a contact spring, defining a pressure release channel, having at least one tab in electrical contact with either the positive or the negative electrode;
a pressure release vent closing the vent channel, said pressure release vent rupturing in response to a predetermined internal cell pressure;
a retainer, also defining the pressure release channel, crimped in a C-shape around the contact spring and the pressure release vent, said retainer forming a conductive path with the contact spring; and
an insulating gasket disposed around the retainer, said insulating gasket separating the collector assembly from making electrical contact with the container and sealing the cell to prevent electrolyte leakage.
2. The cell of claim 1 , wherein the pressure release vent comprises at least a first layer of a composition selected from the group consisting of: metal, polymer, and mixtures thereof.
3. The cell of claim 1 , wherein the pressure release vent has a thickness of 0.254 mm or less.
4. The cell of claim 1 , wherein the contact spring further comprises a peripheral flange forming a continuous annulus surrounding the pressure release channel.
5. The cell of claim 1 , wherein the pressure release vent comprises a first layer having a vapor transmission rate of electrolyte less than 11.81 g·mm/(day·mm 2 ).
6. The cell of claim 2 , wherein the pressure release vent comprises a second layer comprising a composition selected from the group consisting of: polyethylene, polypropylene, polybutylene terephthalate, polyethylene terephthalate, ethylene acrylic acid, ethylene methacrylic acid, polyethylene methacrylic acid, and mixtures thereof.
7. The cell of claim 6 , wherein the pressure release vent comprises a third layer, the first layer being disposed between the second layer and the third layer, and the third layer comprising a composition selected from the group consisting of: polyethylene, polypropylene, polybutylene terephthalate, polyethylene terephthalate, ethylene acrylic acid, ethylene methacrylic acid, polyethylene methacrylic acid, and mixtures thereof.
8. The cell of claim 7 , wherein the first layer comprises aluminum.
9. The cell of claim 1 , wherein the collector assembly comprises a second gasket disposed between the retainer and at least one of the contact spring and the pressure release vent.
10. The cell of claim 1 , wherein the contact spring comprises a continuous flange, surrounding the pressure release channel, the continuous flange having a continuous projection thereon.
11. The cell of claim 1 , wherein the retainer and the pressure release vent are bonded together.
12. The cell of claim 10 , wherein the contact spring and the pressure release vent are bonded together.
13. The cell of claim 1 , wherein the pressure release vent ruptures at a pressure that ranges from 10.5 kg/cm 2 to 42.3 kg/cm 2 at a temperature that ranges from 20° C. to 25° C.
14. The cell of claim 1 , wherein the pressure release vent comprises a layer of a composition comprising aluminum, and the pressure release vent member has a maximum thickness of 0.254 mm.
15. The cell of claim 14 , wherein the pressure release vent comprises a second layer and a third layer of a composition selected from the group consisting of polyethylene, polypropylene, polybutylene terephthalate, polyethylene terephthalate, ethylene acrylic acid, ethylene methacrylic acid, polyethylene methacrylic acid, and mixtures thereof.
16. The cell of claim 15 , wherein the cell further comprises a positive temperature coefficient device disposed between the contact terminal and the retainer.
17. The cell of claim 16 , wherein the positive electrode comprises FeS 2 and the negative electrode comprises lithium metal.
18. The cell of claim 17 , wherein the retainer has a peripheral edge that is substantially circular.
19. The cell of claim 18 , wherein the housing is cylindrical.
20. An electrochemical battery cell comprising a housing, an electrode assembly comprising a positive electrode, a negative electrode and a separator disposed between the electrodes, and an electrolyte, the housing comprising:
a container with an open end in which the electrode assembly and electrolyte are disposed; and
a collector assembly disposed between the electrode assembly and the open end of housing, the collector assembly comprising:
a contact terminal;
a retainer that defines a first opening;
a contact spring attached to the electrode assembly, wherein the contact spring has a peripheral flange that defines a second opening, the first and second opening defining an pressure release channel; and
a pressure release vent member having a peripheral portion disposed between the retainer and the contact spring and closing the pressure release channel between the first opening and the second opening, the pressure release vent member capable of rupturing in response to internal cell pressure that is at least as high as a predetermined release pressure thereby allowing matter to escape through the first opening of the retainer;
wherein the retainer and the contact spring flange form a conductive path between the electrode assembly and the contact terminal cooperate with the pressure release vent member to form a seal between the pressure release vent member and the retainer; and
wherein the retainer has a crimp that applies a compressive force to the pressure release vent member and the contact spring.
21. The cell of claim 20 , wherein the burst pressure of the pressure release vent member ranges from 10.5 kg/cm 2 to 42.3 kg/cm 2 at a temperature that ranges from 20° C. to 25° C.
22. The cell of claim 20 , wherein the pressure release vent member comprises at least a first layer of a composition selected from the group consisting of: metal, polymer and mixtures thereof.
23. The cell of claim 22 , wherein a first layer of the pressure release vent member comprises aluminum.
24. The cell of claim 23 , wherein the pressure release vent member comprises a second layer comprising a composition selected from the group consisting of: polyethylene, polypropylene, polybutylene terephthalate, polyethylene terephthalate, ethylene acrylic acid, ethylene methacrylic acid, polyethylene methacrylic acid, and mixtures thereof.
25. The cell of claim 24 , wherein the pressure release vent member comprises a third layer, the first layer being disposed between the second layer and a third layer, and the third layer comprising a composition selected from the group consisting of: polyethylene, polypropylene, polybutylene terephthalate, polyethylene terephthalate, ethylene acrylic acid, ethylene methacrylic acid, polyethylene methacrylic acid, and mixtures thereof.
26. The cell of claim 25 , wherein the second layer comprises polyethylene and the third layer comprises polyethylene.
27. The cell of claim 20 , wherein the peripheral flange of the contact spring comprises a continuous flange surrounding the first opening, the continuous flange having a continuous projection thereon.
28. The cell of claim 27 , wherein the retainer has a crimp that applies a compressive force to the peripheral portion of the pressure release vent member and the peripheral flange of the contact spring.
29. The cell of claim 28 , wherein the collector assembly further comprises:
a gasket; and
a positive temperature coefficient device disposed between the contact terminal and the retainer.
30. The cell of claim 29 , wherein the retainer and the pressure release vent member are bonded together.
31. The cell of claim 30 , wherein the positive electrode comprises FeS 2 and the negative electrode comprises lithium metal.
32. The cell of claim 30 , wherein the retainer has a peripheral edge that is substantially circular.
33. The cell of claim 30 , wherein the housing is cylindrical.
34. The cell of claim 1 , wherein the collector assembly further comprises a contact terminal.
35. The cell of claim 1 , wherein the collector assembly further comprises a PTC device.
36. The cell of claim 35 , wherein the PTC device is disposed between the contact terminal and the retainer.
37. The cell of claim 1 , wherein the collector assembly further comprises an internal gasket.
38. The cell of claim 37 , wherein the internal gasket has a shape selected from the group consisting of: an L-shape, a C-shape and a substantially flat washer.
39. The cell of claim 10 , wherein the continuous projection is a downward projecting annular groove.
40. The cell of claim 39 , wherein the annular groove has a V-shaped profile.
41. The cell of claim 4 , wherein the peripheral flange has a downward and inward rolled edge.