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 cell, comprising:
a cylindrical container having: a closed bottom, an open top end and a bead that separates top and bottom portions of the container;
an electrode assembly disposed in the bottom portion of the container, the electrode assembly having: a positive electrode, a negative electrode and a separator disposed between the electrodes, and an electrolyte;
a collector assembly disposed within the open top end of the container so that an outermost edge of the top end is crimped around the collector assembly, the collector assembly having: a pressure release vent member and a retainer, both of which define a pressure release channel; a pressure release vent member disposed across the pressure release channel; a terminal; and a contact member which establishes a direct electrical connection between the electrode assembly and the collector assembly; and
an insulating gasket positioned in the top portion of the container between the container and the collector assembly so that the insulating gasket, in cooperation with the bead and the crimped edge of the top portion of the container, is compressed along an entire peripheral portion of the collector assembly to form a seal for the electrochemical cell.
2. The electrochemical cell according to claim 1 , wherein the contact member further includes an axially extending wall in contact with the gasket.
3. The electrochemical cell according to claim 2 , wherein the contact member further includes a peripheral flange that protrudes radially outward from the axially extending wall and, in cooperation with the bead, exerts axial compression with a portion of a gasket.
4. The electrochemical cell according to claim 1 , wherein the contact member further includes a peripheral flange that, in cooperation with the bead, exerts axial compression with a portion of a gasket.
5. The electrochemical cell according to claim 1 , wherein the pressure release vent member is 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 opening of the contact member, and wherein the pressure release vent member comprises at least a first layer comprising one or more of a metal and a polymer.
6. The electrochemical cell according to claim 5 , wherein the pressure release vent member first layer has a vapor transmission rate of electrolyte less than 11.81 g·mm/(day·mm 2 ).
7. The electrochemical cell according to claim 6 , wherein the pressure release vent member comprises a second layer comprising one or more of polyethylene, polypropylene, polybutylene terephthalate, polyethylene terephthalate, ethylene acrylic acid, ethylene methacrylic acid and polyethylene methacrylic acid, and wherein the pressure release vent member comprises a third layer, the first layer being disposed between the second layer and the third layer, and the third layer comprising one or more of polyethylene, polypropylene, polybutylene terephthalate, polyethylene terephthalate, ethylene acrylic acid, ethylene methacrylic acid and polyethylene methacrylic acid.
8. The electrochemical cell according to claim 7 , wherein the first layer comprises aluminum.
9. The electrochemical cell according to claim 5 , wherein the pressure release vent member 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.
10. The electrochemical cell according to claim 1 , wherein the contact member and pressure release vent member are bonded together.
11. The electrochemical cell according to claim 10 , wherein a positive temperature coefficient device is disposed between the terminal and the retainer.
12. The electrochemical cell according to claim 1 , wherein the positive electrode comprises FeS 2 and the negative electrode comprises lithium metal, and wherein the electrode assembly is spiral wound.
13. The electrochemical cell according to claim 1 , wherein a positive temperature coefficient device is disposed between the terminal and the retainer.