Lithium ion battery capable of being discharged to zero volts
First Claim
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1. A rechargeable battery comprising:
- one positive electrode, said positive electrode comprising a metal substrate having one positive active material formed thereon, said positive active material consisting of a lithium oxide comprising cobalt and nickel;
a negative electrode comprising a metal substrate selected from the group consisting of titanium and titanium alloy having a second active material comprising carbon formed thereon;
an electrolyte wherein said negative electrode and said electrolyte form a solid electrolyte interface (SEI) layer, said SEI layer being susceptible of damage when a voltage potential exceeding a Film Dissolution Potential (FDP) is applied thereto, and wherein said FDP is lower than the maximum positive operating potential of the battery;
said positive and negative electrodes defining a Zero Volt Crossing Potential (ZCP) relative to a reference level when the voltage between said electrodes is zero; and
wherein said positive and negative electrodes are selected and configured to establish ZCP at a lower level than FDP to prevent dissolution of said SEI layer during storage at a predetermined temperature.
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Abstract
A lithium ion battery particularly configured to be able to discharge to a very low voltage, e.g. zero volts, without causing permanent damage to the battery. More particularly, the battery is configured to define a Zero Volt Crossing Potential (ZCP) which is lower than a Substrate Dissolution Potential (SDP) to thus avoid low voltage substrate damage. The configuration includes a lithium nickel cobalt oxide positive active material combined with negative electrode comprising a titanium or titamum alloy substrate having a carbon active material formed thereon.
123 Citations
27 Claims
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1. A rechargeable battery comprising:
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one positive electrode, said positive electrode comprising a metal substrate having one positive active material formed thereon, said positive active material consisting of a lithium oxide comprising cobalt and nickel;
a negative electrode comprising a metal substrate selected from the group consisting of titanium and titanium alloy having a second active material comprising carbon formed thereon;
an electrolyte wherein said negative electrode and said electrolyte form a solid electrolyte interface (SEI) layer, said SEI layer being susceptible of damage when a voltage potential exceeding a Film Dissolution Potential (FDP) is applied thereto, and wherein said FDP is lower than the maximum positive operating potential of the battery;
said positive and negative electrodes defining a Zero Volt Crossing Potential (ZCP) relative to a reference level when the voltage between said electrodes is zero; and
whereinsaid positive and negative electrodes are selected and configured to establish ZCP at a lower level than FDP to prevent dissolution of said SEI layer during storage at a predetermined temperature. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
said positive and negative electrodes are selected and configured to establish ZCP at a lower level than SDP in order to prevent dissolution of the negative substrate during storage at said predetermined temperature.
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3. The battery of claim 1 wherein said negative electrode active material consists of carbon.
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4. The battery of claim 1 wherein said electrolyte consists of a liquid electrolyte.
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5. The battery of claim 4 wherein said liquid electrolyte comprises a lithium salt dissolved in EC:
- DEC.
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6. The battery of claim 5 wherein said lithium salt is LiPF6.
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7. The battery of claim 1 wherein said predetermined temperature is body temperature.
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8. The battery of claim 1 wherein said predetermined temperature is about 37°
- C.
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9. The battery of claim 1 wherein said predetermined temperature is about 25°
- C.
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10. The battery of claim 1 further comprising a battery management circuit that attempts to stop battery discharge when the battery voltage reaches 2.5 V, wherein the maximum battery voltage is greater than 2.5 V.
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11. The battery of claims 1 wherein said ZCP is greater than about 3 V vs. Li/Li+.
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12. The battery of claim 1 wherein said positive electrode has a positive discharge curve having a negative slope over most of said positive discharge curve, wherein said negative slope is more negative than the negative slope over most of the discharge curve of LiCoO2.
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13. The battery of claim 1 further including a hermetically sealed case for housing said positive and negative electrodes.
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14. The battery of claim 13 wherein said case is configured to be implanted in a patient'"'"'s body.
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15. The battery of claim 13 wherein said case has a volume of less than 30 cc.
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16. A rechargeable battery comprising:
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one positive electrode, said positive electrode comprising a metal substrate having one positive active material formed thereon, said positive active material consisting of a lithium oxide comprising cobalt and nickel;
a negative electrode comprising a substrate selected from the group consisting of titanium and titanium alloy having a second active material comprising carbon formed thereon;
said negative electrode being susceptible of damage when a voltage exceeding a Damage Potential Threshold (DPT) is applied thereto, and wherein said DPT is lower than the maximum positive operating potential of the battery;
said positive and negative electrodes defining a Zero Volt Crossing Potential (ZCP) relative to a reference level when the voltage between said electrodes is zero; and
whereinsaid positive and negative electrodes are selected and configured to define a value of ZCP which is less than the value of DPT at a predetermined temperature. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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Specification