Method for charging lithium-ion battery

• US 7,635,541 B2
• Filed: 10/27/2005
• Issued: 12/22/2009
• Est. Priority Date: 10/29/2004
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Howard, William G., Scott, Erik R., Schmidt, Craig L.
• Primary Examiner(s): Ryan; Patrick
• Assistant Examiner(s): Parsons; Thomas H.
• Application Number:
  US11/260,853
• Publication Number:
  US 20060093894A1
• Time in Patent Office: 1,517 Days
• Field of Search: 429/218.1, 429/223, 429/224, 429/231.5, 429/231.95, 607/2, 607/9, 607/41, 607/116, 607/137, 320/162, 320/137
• US Class Current: 429/231.95
• CPC Class Codes: A61N 1/3787 from an external energy source
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 10/446 Initial charging measures
• CPC Class Codes: H01M 2004/021 Physical characteristics, e.g. porosity, surface area
• CPC Class Codes: H01M 4/485 of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy H01M4/505, H01M4/525 take precedence
• CPC Class Codes: H01M 4/505 of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
• CPC Class Codes: H01M 4/525 of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
• CPC Class Codes: H01M 4/661 Metal or alloys, e.g. alloy coatings H01M4/669 take precedence
• CPC Class Codes: H02J 2310/23 The load being a medical device, a medical implant, or a life supporting device
• CPC Class Codes: H02J 7/0071 with a programmable schedule
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A method for charging an implantable medical device includes charging a lithium-ion battery provided in a medical device, the lithium-ion battery having a negative electrode with a lithium titanate active material. For at least a portion of the charging, the potential of the negative electrode is more than approximately 70 millivolts below the equilibrium potential of the negative electrode.

Claims

1. A method for charging an implantable medical device comprising:

charging a lithium-ion battery provided in a medical device, the lithium-ion battery having a negative electrode with a lithium titanate active material;

wherein for at least a portion of the charging, the potential of the negative electrode is more than approximately 70 millivolts below the equilibrium potential of the negative electrode.

2. The method of claim 1, wherein for at least a portion of the charging, the potential of the negative electrode is more than approximately 100 millivolts below the equilibrium potential of the negative electrode.

3. The method of claim 1, wherein the step of charging the lithium-ion battery maintains the potential of the negative electrode above zero volts compared to a lithium reference electrode.

4. The method of claim 1, wherein the step of charging the lithium-ion battery is part of a charging operation that utilizes a constant charging voltage.

5. The method of claim 1, wherein the step of charging the lithium-ion battery is part of a charging operation that utilizes a constant charging current.

6. The method of claim 1, wherein the step of charging the lithium-ion battery is part of a charging operation in which a first portion of the charging operation utilizes a constant charging current and a second portion of the charging operation utilizes a constant charging voltage.

7. The method of claim 1, wherein the step of charging the lithium-ion battery is part of a charging operation that utilizes a step-down current method.

8. The method of claim 1, further comprising terminating the charging of the lithium-ion battery when a predetermined condition is met, the predetermined condition selected from the group consisting of (a) an abrupt decrease in negative electrode potential, (b) the passing of a predetermined amount of time, (c) the current of the lithium-ion battery falling below a predetermined threshold, and (d) the slope of the current of the lithium-ion battery with time (di/dt) falling below a predetermined threshold.

9. The method of claim 1, further comprising terminating the charging of the lithium-ion battery when a predetermined condition is met, the predetermined condition selected from the group consisting of(a) the voltage of the lithium-ion battery exceeding a predetermined threshold, (b) the slope of the voltage of the lithium-ion battery with time (dV/dt) exceeding a predetermined threshold, and (c) the slope of the voltage of the lithium-ion battery with capacity (dV/dQ) exceeding a predetermined threshold.

10. The method of claim 1, wherein the lithium-ion battery comprises a positive electrode comprising a current collector and an active material comprising a material selected from the group consisting of LiCoO₂, LiMn₂O₄, LiMn_xCo_yNi₍₁₋

x−

y)O₂, LiAl_xCo_yNi<sub>(1−

x−

y)</sub>O₂, LiTi_xCo_yNi<sub>(1−

x−

y)</sub>O₂, and combinations thereof.

11. The method of claim 1, wherein the negative electrode comprises a current collector comprising a material selected from the group consisting of aluminum, titanium, silver, and combinations thereof.

12. The method of claim 1, wherein the lithium titanate active material comprises Li₄Ti₅O₁₂.

13. The method of claim 1, wherein the lithium titanate active material comprises at least five percent nanoparticles.

14. The method of claim 1, wherein the step of charging the battery is performed with the medical device implanted in a patient.

15. The method of claim 14, wherein the medical device is selected from the group consisting of a neurological stimulation device, a cardiac defibrillator, a cardiac pacemaker, a cardiac contractility module, a cardiac contractility modulator, a cardioverter, a drug administration device, a cochlear implant, a hearing aid, a sensor, a telemetry device, and a diagnostic recorder.

16. The method of claim 15, wherein the step of charging the battery utilizes inductive charging.

17. The method of claim 1, wherein the lithium-ion battery has a positive electrode that has a potential that is greater than approximately 2.8 volts.

18. The method of claim 1, wherein the voltage of the lithium-ion battery is greater than approximately 1.3 volts.

19. The method of claim 1, wherein the lithium-ion battery has a capacity between approximately 1 mAh and 1000 mAh.

20. The method of claim 1, wherein the step of charging the lithium-ion battery is not suspended during charging to determine the state of charge or equilibrium voltage of the lithium-ion battery.

21. A method of charging a lithium-ion battery comprising:

charging a lithium-ion battery in a charging operation, the lithium-ion battery including a negative electrode that comprises a lithium titanate material;

wherein for at least a portion of the charging operation the overpotential of the negative electrode is greater than approximately 70 millivolts;

wherein the lithium battery is included in an implantable medical device and the charging operation does not result in lithium plating at the negative electrode.

22. The method of claim 21, wherein for at least a portion of the charging operation the overpotential of the negative electrode is greater than approximately 100 millivolts.

23. The method of claim 21, wherein the battery has a capacity between approximately 1 mAh and 1000 mAh.

24. The method of claim 21, wherein the charging operation utilizes a constant charging voltage.

25. The method of claim 21, wherein the charging operation utilizes a constant charging current.

26. The method of claim 21, further comprising terminating the charging operation when a predetermined condition is met, the predetermined condition selected from the group consisting of (a) an abrupt decrease in negative electrode potential, (b) the passing of a predetermined amount of time, (c) the current of the lithium-ion battery falling below a predetermined threshold, and (d) the slope of the current of the lithium-ion battery with time (di/dt) falling below a predetermined threshold.

27. The method of claim 21, further comprising terminating the charging operation when a predetermined condition is met, the predetermined condition selected from the group consisting of (a) the voltage of the lithium-ion battery exceeding a predetermined threshold, (b) the slope of the voltage of the lithium-ion battery with time (dV/dt) exceeding a predetermined threshold, and (c) the slope of the voltage of the lithium-ion battery with capacity (dV/dQ) exceeding a predetermined threshold.

28. The method of claim 21, wherein the negative electrode comprises a current collector comprising a material selected from the group consisting of aluminum, titanium, silver, and combinations thereof.

29. The method of claim 21, wherein the lithium titanate active material comprises Li₄Ti₅O₁₂.

30. The method of claim 21, wherein the medical device is selected from the group consisting of a neurological stimulation device, a cardiac defibrillator, a cardiac pacemaker, a cardiac contractility module, a cardiac contractility modulator, a cardioverter, a drug administration device, a cochlear implant, a hearing aid, a sensor, a telemetry device, and a diagnostic recorder.

31. The method of claim 21, wherein the charging operation is performed while the medical device is implanted in a patient.

32. A method of charging a lithium-ion battery comprising:

inductively charging a lithium-ion battery according to a charging routine that provides an overpotential of at least 70 millivolts to a negative electrode of the battery for at least a portion of the charging routine, the lithium-ion battery comprising a lithium titanate negative active material.

33. The method of claim 32, wherein the lithium-ion battery has a capacity between approximately 1 mAh and 1000 mAh.

34. The method of claim 33, wherein the charging routine provides an overpotential of at least 100 millivolts to the negative electrode.

35. The method of claim 32, wherein the charging operation utilizes at least one of a constant charging voltage and a constant charging current.

36. The method of claim 32, wherein the negative electrode comprises a current collector comprising a material selected from the group consisting of aluminum, titanium, and silver.

37. The method of claim 32, wherein the lithium-ion battery is provided in a medical device implanted in a patient, the medical device selected from the group consisting of a neurological stimulation device, a cardiac defibrillator, a cardiac pacemaker, a cardiac contractility module, a cardiac contractility modulator, a cardioverter, a drug administration device, a cochlear implant, a hearing aid, a sensor, a telemetry device, and a diagnostic recorder.

38. The method of claim 32, wherein the lithium titanate active material comprises Li₄Ti₅O₁₂.