Lithium secondary battery

• US 20090087731A1
• Filed: 09/25/2008
• Published: 04/02/2009
• Est. Priority Date: 09/27/2007
• Status: Abandoned Application

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Kamino, Maruo, Fukui, Atsushi
• Application Number:
  US12/232,917
• Publication Number:
  US 20090087731A1
• Time in Patent Office: Days
• US Class Current: 429/164
• 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 10/0587 of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
• CPC Class Codes: H01M 2004/021 Physical characteristics, e.g. porosity, surface area
• 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 4/134 Electrodes based on metals, Si or alloys
• CPC Class Codes: H01M 4/624 Electric conductive fillers
• CPC Class Codes: H01M 50/103 prismatic or rectangular H01M50/109, H01M50/11 take precedence
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A lithium secondary battery includes: a positive electrode having a positive electrode active material layer disposed on a positive electrode current collector, the positive electrode active material layer containing a positive electrode binder and a positive electrode active material containing a layered lithium-transition metal composite oxide; a negative electrode having a negative electrode current collector and a negative electrode active material layer disposed on the negative electrode current collector, the negative electrode active material layer containing a negative electrode binder and a negative electrode active material containing particles of silicon and/or a silicon alloy; and a non-aqueous electrolyte. Al₂O₃ particles are firmly adhered to a surface of the lithium-transition metal composite oxide so that a BET specific surface area of the positive electrode active material after the adherence of the Al₂O₃ particles is from 1.5 times to 8 times greater than that before the adherence of the Al₂O₃ particles

Claims

1. A lithium secondary battery comprising:

a battery case;

a non-aqueous electrolyte; and

an electrode assembly accommodated in the battery case, the electrode assembly comprising a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode, the positive electrode and the negative electrode being disposed facing each other across the separator and being wound; and

the negative electrode comprising a negative electrode current collector and a negative electrode active material layer disposed on the negative electrode current collector, the negative electrode active material layer comprising a negative electrode binder and a negative electrode active material containing particles of silicon and/or a silicon alloy; and

the positive electrode comprising a positive electrode current collector and a positive electrode active material layer disposed on the positive electrode current collector, the positive electrode active material layer comprising a positive electrode binder and a positive electrode active material containing a layered lithium-transition metal composite oxide, wherein Al₂O₃ particles are adhered to a surface of the lithium-transition metal composite oxide so that a BET specific surface area of the positive electrode active material after the adherence of the Al₂O₃ particles is from 1.5 times to 8 times greater than that before the adherence of the Al₂O₃ particles.

2. The lithium secondary battery according to claim 1, wherein the positive electrode active material layer has a porosity of from 15% to 28%.

3. The lithium secondary battery according to. claim 1, wherein the BET specific surface area of the positive electrode active material after the adherence of the Al₂O₃ particles is from 2.5 times to 7.5 times greater than that before the adherence of the Al₂O₃ particles.

4. The lithium secondary battery according to claim 2, wherein the BET specific surface area of the positive electrode active material after the adherence of the Al₂O₃ particles is from 2.5 times to 7.5 times greater than that before the adherence of the Al₂O₃ particles.

5. The lithium secondary battery according to claim 1, wherein Li₃PO₄ particles are adhered to the lithium-transition metal composite oxide in addition to the Al₂O₃ particles so that the BET specific surface area can be obtained.

6. The lithium secondary battery according to claim 2, wherein Li₃PO₄ particles are adhered to the lithium-transition metal composite oxide in addition to the Al₂O₃ particles so that the BET specific surface area can be obtained.

7. The lithium secondary battery according to claim 1, wherein the electrode assembly is in a spiral shape, and the battery case is in a cylindrical shape.

8. The lithium secondary battery according to claim 2, wherein the electrode assembly is in a spiral shape, and the battery case is in a cylindrical shape.

9. The lithium secondary battery according to claim 1, wherein the non-aqueous electrolyte contains dimethyl carbonate as a solvent.

10. The lithium secondary battery according to claim 2, wherein the non-aqueous electrolyte contains dimethyl carbonate as a solvent.

11. The lithium secondary battery according to claim 3, wherein the non-aqueous electrolyte contains dimethyl carbonate as a solvent.

12. The lithium secondary battery according to claim 4, wherein the non-aqueous electrolyte contains dimethyl carbonate as a solvent.

13. The lithium secondary battery according to claim 5, wherein the non-aqueous electrolyte contains dimethyl carbonate as a solvent.

14. The lithium secondary battery according to claim 6, wherein the non-aqueous electrolyte contains dimethyl carbonate as a solvent.

15. The lithium secondary battery according to claim 7, wherein the non-aqueous electrolyte contains dimethyl carbonate as a solvent.

16. The lithium secondary battery according to claim 8, wherein the non-aqueous electrolyte contains dimethyl carbonate as a solvent.

17. The lithium secondary battery according to claim 9, wherein the non-aqueous electrolyte contains dimethyl carbonate as a solvent.