NEGATIVE-LIMITED LITHIUM-ION BATTERY

• US 20090035662A1
• Filed: 09/29/2008
• Published: 02/05/2009
• Est. Priority Date: 10/29/2004
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Jain, Gaurav, Scott, Erik R., Schmidt, Craig L., Eberman, Kevin W.
• Granted Patent: US 7,927,742 B2
• Time in Patent Office: Days
• US Class Current: 429/231.500
• CPC Class Codes: A61N 1/378 Electrical supply
• 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 2010/4292 Aspects relating to capacity ratio of electrodes/electrolyte or anode/cathode
• CPC Class Codes: H01M 4/131 Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• 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 4/625 Carbon or graphite
• CPC Class Codes: H01M 4/661 Metal or alloys, e.g. alloy coatings H01M4/669 take precedence
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

A rechargeable lithium-ion battery includes a positive electrode that includes a first current collector and a first active material. The battery also includes an electrolyte and a negative electrode that includes a second current collector and a second active material, where the second active material includes a lithium titanate material. The positive electrode has a first capacity and the negative electrode has a second capacity, the second capacity being less than the first capacity such that the rechargeable lithium-ion battery is negative-limited.

Claims

1. A rechargeable lithium-ion battery comprising:

a positive electrode comprising a first current collector and a first active material;

a negative electrode comprising a second current collector and a second active material, the second active material comprising a lithium titanate material; and

an electrolyte;

wherein the positive electrode has a first capacity and the negative electrode has a second capacity, the second capacity being less than the first capacity such that the rechargeable lithium-ion battery is negative-limited.

2. The rechargeable lithium-ion battery of claim 1, wherein the lithium titanate material comprises Li₄Ti₅O₁₂.

3. The rechargeable lithium-ion battery of claim 1, wherein the lithium titanate material is configured to cycle lithium at a potential of greater than 0.2 volts versus a lithium reference electrode.

4. The rechargeable lithium-ion battery of claim 1, wherein the ratio of the second capacity to the first capacity is approximately 0.93.

5. The rechargeable lithium-ion battery of claim 1, wherein the ratio of the second capacity to the first capacity is approximately 0.85.

6. The rechargeable lithium-ion battery of claim 1, wherein the ratio of the second capacity to the first capacity is less than approximately 0.90.

7. The rechargeable lithium-ion battery of claim 6, wherein the ratio of the second capacity to the first capacity is greater than approximately 0.70.

8. The rechargeable lithium-ion battery of claim 7, wherein the ratio of the second capacity to the first capacity is greater than approximately 0.80.

9. The rechargeable lithium-ion battery of claim 8, wherein the ratio of the second capacity to the first capacity is approximately 0.84.

10. The rechargeable lithium-ion battery of claim 1, wherein the ratio of the second capacity to the first capacity is approximately 0.73.

11. The rechargeable lithium-ion battery of claim 1, wherein the first active material comprises LiCoO₂.

12. The rechargeable lithium-ion battery of claim 1, wherein the electrolyte consists essentially of ethylene carbonate, ethylmethyl carbonate, and a salt of LiPF₆.

13. The rechargeable lithium-ion battery of claim 1, wherein the electrolyte does not include a molten salt.

14. The rechargeable lithium-ion battery of claim 1, wherein the electrolyte does not include additives that are intended to prevent degradation due to oxidation of the positive electrode.

15. The rechargeable lithium-ion battery of claim 14, wherein the electrolyte does not include biphenyl.

16. The rechargeable lithium-ion battery of claim 1, wherein the battery is configured for use in a medical device.

17. The rechargeable lithium-ion battery of claim 1, wherein the positive electrode and the negative electrode are provided as wound electrodes.

18. A rechargeable lithium-ion battery comprising:

a positive electrode comprising a first current collector and a first active material;

a negative electrode comprising a second current collector and a second active material, the second active material comprising a material that cycles lithium at a potential of greater than 0.2 volts versus a lithium reference electrode; and

an electrolyte comprising ethylene carbonate and free of molten salt;

wherein the positive electrode has a first capacity and the negative electrode has a second capacity, the second capacity being less than the first capacity;

whereby the rechargeable lithium-ion battery exhibits improved resistance to capacity fade after repeated cycling as compared to batteries having balanced electrode capacities.

19. The rechargeable lithium-ion battery of claim 18, wherein the second active material is a lithium titanate material.

20. The rechargeable lithium-ion battery of claim 19, wherein the lithium titanate material comprises Li₄Ti₅O₁₂.

21. The rechargeable lithium-ion battery of claim 20, wherein the first active material comprises LiCoO₂.

22. The rechargeable lithium-ion battery of claim 18, wherein the electrolyte further comprises ethylmethyl carbonate, and a salt of LiPF₆.

23. The rechargeable lithium-ion battery of claim 18, wherein the ratio of the second capacity to the first capacity is less than approximately 0.90.

24. The rechargeable lithium-ion battery of claim 23, wherein the ratio of the second capacity to the first capacity is greater than approximately 0.70.

25. The rechargeable lithium-ion battery of claim 24, wherein the ratio of the second capacity to the first capacity is greater than approximately 0.80.

26. The rechargeable lithium-ion battery of claim 18, wherein the ratio of the second capacity to the first capacity is approximately 0.84.

27. The rechargeable lithium-ion battery of claim 18, wherein the ratio of the second capacity to the first capacity is approximately 0.73.

28. The rechargeable lithium-ion battery of claim 18, wherein the battery is configured for use in a medical device.

29. The rechargeable lithium-ion battery of claim 18, wherein the positive electrode and the negative electrode are provided as wound electrodes.

30. A rechargeable lithium-ion battery comprising:

a positive electrode;

a negative electrode comprising an active material that cycles lithium at a potential of greater than 0.2 volts versus a lithium reference electrode; and

an electrolyte that is free of molten salt;

wherein the rechargeable lithium-ion battery has a negative-limited cell balance such that the positive electrode has greater capacity than the negative electrode;

whereby the rechargeable lithium-ion battery exhibits improved resistance to capacity fade after repeated cycling as compared to batteries having balanced electrode capacities.

31. The rechargeable lithium-ion battery of claim 30, wherein the active material is a lithium titanate material.

32. The rechargeable lithium-ion battery of claim 31, wherein the lithium titanate material comprises Li₄Ti₅O₁₂.

33. The rechargeable lithium-ion battery of claim 32, wherein the positive electrode comprises an active material comprising LiCoO₂.

34. The rechargeable lithium-ion battery of claim 30, wherein the molten salt free electrolyte consists essentially of ethylene carbonate, ethylmethyl carbonate, and a salt of LiPF₆.

35. The rechargeable lithium-ion battery of claim 30, wherein the cell balance is less than approximately 0.90.

36. The rechargeable lithium-ion battery of claim 35, wherein the cell balance is greater than approximately 0.70.

37. The rechargeable lithium-ion battery of claim 36, wherein the cell balance is greater than approximately 0.80.

38. The rechargeable lithium-ion battery of claim 30, wherein the cell balance is approximately 0.84.

39. The rechargeable lithium-ion battery of claim 30, wherein the cell balance is approximately 0.73.

40. The rechargeable lithium-ion battery of claim 30, wherein the battery is configured for use in a medical device.

41. The rechargeable lithium-ion battery of claim 30, wherein the positive electrode and the negative electrode are provided as wound electrodes.