Cell cap assembly having frangible tab disconnect mechanism
First Claim
1. A cell cap subassembly for controlling pressure build-up in a cell interior having an electrode, said cell cap subassembly comprising:
- a terminal contact for making electrical contact with an external circuit;
a deflection member being in electrical communication with said terminal contact, said deflection member undergoing a displacement in response to an increase in pressure within the cell interior;
a frangible member connected to and making electrical contact with said deflection member, said frangible member having a defined frangible region located away from said deflection member, wherein when said deflection member undergoes displacement in response to a first defined pressure, said frangible member breaks at said frangible region and thereby electrically disconnects said terminal contact from said electrode.
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Accused Products
Abstract
A cell pressure control system is disclosed which includes a conductive frangible tab which tears in response to a defined pressure. The frangible tab is affixed at one position to a stationary member and at another position to a deflection member which deflects in response to increasing internal cell pressure. When the cell pressure increases to a dangerous level, the deflection member exerts sufficient pressure on the frangible tab to cause it to break. When the tab breaks, the cell goes to open circuit, thus reducing the danger of continued pressure build up. If the cell'"'"'s internal pressure continues to increase even after the pressure contact is opened, a second stage of the pressure control mechanism may be activated. Specifically, a pressure rupturable region in the above-mentioned deflection member will rupture and release the cell'"'"'s internal pressure.
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Citations
24 Claims
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1. A cell cap subassembly for controlling pressure build-up in a cell interior having an electrode, said cell cap subassembly comprising:
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a terminal contact for making electrical contact with an external circuit; a deflection member being in electrical communication with said terminal contact, said deflection member undergoing a displacement in response to an increase in pressure within the cell interior; a frangible member connected to and making electrical contact with said deflection member, said frangible member having a defined frangible region located away from said deflection member, wherein when said deflection member undergoes displacement in response to a first defined pressure, said frangible member breaks at said frangible region and thereby electrically disconnects said terminal contact from said electrode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method for controlling pressure build-up in a cell having an electrode, the method comprising the following steps:
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(a) providing a cell having a cell cap subassembly and a cell interior, the cell cap subassembly including (i) a terminal contact for making electrical contact with an external circuit, (ii) a deflection member that is in electrical communication with said terminal contact and undergoes a displacement in response to an increase in pressure within the cell interior, and (iii) a frangible member connected to and making electrical contact with said deflection member, said frangible member having a defined frangible region located away from said deflection member; and (b) causing the deflection member to undergo displacement in response to a first defined pressure such that said frangible member breaks at said frangible region and thereby electrically disconnects said terminal contact from said electrode. - View Dependent Claims (16, 17, 18)
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19. A lithium ion cell comprising:
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(a) a cell container having a cell cap subassembly including (i) a terminal contact for making electrical contact with an external circuit, (ii) a conductive deflection member that is in electrical communication with said terminal contact and undergoes a displacement in response to an increase in pressure within the cell interior, and (iii) a frangible member connected to and making electrical contact with said deflection member, said frangible member having a defined frangible region located away from said deflection member, wherein when said deflection member undergoes displacement in response to a first defined pressure, said frangible member breaks at said frangible region and thereby electrically disconnects said terminal contact from said electrode; (b) an anode provided within the cell container and capable of intercalating lithium during charge and deintercalating lithium during discharge, the anode including an anode material; (c) a cathode provided within the cell container and capable of taking up lithium on discharge and releasing lithium on charge, the cathode including a specified cathode material; and (d) an electrolyte conductive to lithium ions and provided within said cell container. - View Dependent Claims (20, 21)
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22. A cell assembly for controlling excessive current in a cell having an electrode, said cell assembly comprising:
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a terminal contact for making electrical contact with an external circuit; a deflection member that undergoes a displacement in response to an increase in pressure within the cell interior, and a frangible permanent fuse in electrical communication with said terminal contact and in electrical communication with said electrode, wherein when the current in the cell exceeds a predefined level, the permanent fuse permanently electrically disconnects the terminal contact from the electrode, and wherein said frangible permanent fuse is connected to said deflection member such that said frangible permanent fuse breaks when the displacement member undergoes said displacement. - View Dependent Claims (23, 24)
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Specification