Charging process for lithium-ion batteries

• US 9,899,710 B2
• Filed: 03/13/2015
• Issued: 02/20/2018
• Est. Priority Date: 04/30/2008
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Scott, Erik R., Jain, Gaurav
• Primary Examiner(s): Fantu, Yalkew
• Assistant Examiner(s): Sharief, Mohammed J
• Application Number:
  US14/657,759
• Publication Number:
  US 20150263392A1
• Time in Patent Office: 1,075 Days
• Field of Search: 320128
• 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 10/0569 characterised by the solvents
• CPC Class Codes: H01M 10/446 Initial charging measures
• CPC Class Codes: H01M 2010/4292 Aspects relating to capacity ratio of electrodes/electrolyte or anode/cathode
• CPC Class Codes: H01M 2300/0028 characterised by the solvent
• 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 4/583 Carbonaceous material, e.g. graphite-intercalation compounds or CFx
• 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
• CPC Class Codes: Y10T 29/49108 Electric battery cell making

Abstract

A method for producing a battery includes providing a battery having a positive electrode, a negative electrode, and an electrolyte that includes a solvent and a salt. The capacity of the negative electrode is less than that of the positive electrode and the negative electrode includes an active material having an average potential versus a lithium reference electrode of greater than approximately 0.2 volts. The method also includes applying an initial charge to the battery at a voltage that is greater than a fully charged voltage of the battery for a sufficient amount of time to cause at least a portion of the solvent to undergo a reduction reaction. The step of applying an initial charge to the battery acts to increase the irreversible capacity loss of the battery during the initial charge and provides the battery with enhanced tolerance to deep discharge conditions.

Claims

1. A method of charging a battery comprising:

providing a lithium-ion battery comprising a positive electrode having a positive active material, a negative electrode having a negative active material and a capacity that is less than that of the positive electrode, and an electrolyte having a solvent, wherein the negative active material has an average cycling potential versus a lithium reference electrode that is greater than a reduction potential at or below which the solvent reduces; and

applying a charging voltage to the battery for a duration while the battery is fully charged, wherein the charging voltage and the duration are sufficient to cause a potential of the negative electrode to fall below the reduction potential.

2. The method according to claim 1, wherein the charging voltage is greater than a fully charged voltage of the battery, and the charging voltage and the duration are sufficient to cause a zero volt crossing potential of the battery to increase to above a decomposition potential of the positive active material.

3. The method according to claim 1, wherein the charging voltage and the duration are sufficient to cause a potential of the negative electrode to fall between 0.6 volts and 1.0 volts below the average cycling potential of the negative active material.

4. The method according to claim 1, wherein the charging potential and the duration are sufficient to cause at least a portion of the solvent to undergo a reduction reaction at the negative electrode.

5. The method according to claim 4, wherein the solvent comprises ethylene carbonate, and the reduction reaction forms a passive film comprising at least one of lithium carbonate or lithium alkyl carbonate.

6. The method according to claim 4, wherein after applying the charging voltage for the duration, the battery has between approximately 12% and 20% irreversible capacity loss.

7. The method according to claim 1, wherein the potential of the negative electrode falls below approximately 0.9 volts versus a lithium reference electrode.

8. The method according to claim 7, wherein the average cycling potential of the negative active material is at least 1.5 volts versus a lithium reference electrode.

9. The method according to claim 7, wherein the potential of the negative electrode falls to between approximately 0.5 and 0.8 volts versus a lithium reference electrode.

10. The method according to claim 1, wherein the charging voltage is applied to the battery for the duration during a formation process of the battery.

11. A method of charging a battery comprising:

providing a lithium-ion battery comprising a positive electrode having a positive active material, a negative electrode having a negative active material and a capacity that is less than that of the positive electrode, and an electrolyte; and

applying a charging voltage to the battery for a duration while the battery is fully charged, wherein the charging voltage is greater than a fully charged voltage of the battery, and the charging voltage and the duration are sufficient to cause a zero volt crossing potential of the battery to increase to above a decomposition potential of the positive active material.

12. The method according to claim 11, wherein the electrolyte has a solvent, and the negative active material has an average cycling potential versus a lithium reference electrode that is greater than a reduction potential at or below which the solvent reduces;

and

wherein the charging voltage and the duration are sufficient to cause a potential of the negative electrode to fall below the reduction potential.

13. The method according to claim 11, wherein the charging voltage and the duration are sufficient to cause a potential of the negative electrode to fall between 0.6 volts and 1.0 volts below an average cycling potential of the negative active material.

14. The method according to claim 11, wherein the positive active material comprises LiCoO₂.

15. The method according to claim 11, wherein the charging voltage is applied to the battery for the duration during a formation process of the battery.

16. A method of charging a battery comprising:

providing a lithium-ion battery comprising a positive electrode having a positive active material, a negative electrode having a negative active material and a capacity that is less than that of the positive electrode, and an electrolyte; and

applying a charging voltage to the battery for a duration while the battery is fully charged, wherein the charging voltage and the duration are sufficient to cause a potential of the negative electrode to fall between 0.6 volts and 1.0 volts below an average cycling potential of the negative active material.

17. The method according to claim 16, wherein the electrolyte comprises a solvent, and the negative active material has an average cycling potential versus a lithium reference electrode that is greater than a reduction potential at or below which the solvent reduces;

and

wherein the charging voltage and the duration are sufficient to cause a potential of the negative electrode to fall below the reduction potential.

18. The method according to claim 16, wherein the charging voltage is greater than a fully charged voltage of the battery, and the charging voltage and the duration are sufficient to cause a zero volt crossing potential of the battery to increase to above a decomposition potential of the positive active material.

19. The method according to claim 16, wherein the negative active material comprises lithium titanate.

20. The method according to claim 16, wherein the charging voltage is applied to the battery for the duration during a formation process of the battery.