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 and an open top end that is closed by a collector assembly;
an electrode assembly disposed in the container, the electrode assembly comprising a positive electrode, a negative electrode and a separator disposed between the electrodes, and an electrolyte;
a gasket positioned between conductive components of the collector assembly and the container;
the collector assembly including a retainer, a contact terminal and a contact spring electrically connected with the contact terminal; and
the contact spring defining an opening, contact spring further including an axially extending wall exerting radial compression of the collector assembly with a portion of the gasket, the contact spring having a peripheral flange extending radially outward from the axially extending wall and exerting axial compression of the collector assembly with a portion of the gasket, the contact spring having a tab electrically connected to the a current collector in the electrode assembly.
2. The electrochemical cell according to claim 1 , wherein the collector assembly further includes a 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 opening of the contact spring.
3. The electrochemical cell according to claim 2 , wherein the pressure release vent member has a first layer that has a vapor transmission rate of electrolyte less than 11.81 g·mm/(day·mm 2 ).
4. The electrochemical cell according to claim 3 , wherein the pressure release vent member first layer comprises one or more of a metal and a polymer.
5. The electrochemical cell according to claim 4 , 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.
6. The electrochemical cell according to claim 2 , wherein a seal is formed between a peripheral portion of the pressure release vent member and a peripheral flange of the contact spring, and wherein the pressure release vent member is disposed across the opening of the contact spring.
7. The electrochemical cell according to claim 2 , wherein a peripheral portion of the pressure release vent member is disposed between the contact spring and a retainer, wherein the retainer defines a second opening.
8. The electrochemical cell according to claim 7 , 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.
9. The electrochemical cell according to claim 2 , wherein the positive electrode comprises FeS 2 and the negative electrode comprises lithium metal, wherein the electrode assembly is spiral wound, and wherein the negative electrode is electrically connected to the container and the positive electrode is electrically connected to the contact terminal.
10. The electrochemical cell according to claim 9 , wherein an insulator is present in the cell and is located around a peripheral portion of the top of the electrode assembly to prevent a current collector of the positive electrode from making contact with the container, and wherein the insulator is in contact with an end surface of the gasket exposed to electrolyte within the cell.
11. The electrochemical cell according to claim 1 , wherein the peripheral flange of the contact spring includes an annular groove.
12. The electrochemical cell according to claim 7 , wherein the peripheral flange of the contact spring includes an annular groove.