Lithium secondary battery

• US 20070231684A1
• Filed: 03/30/2007
• Published: 10/04/2007
• Est. Priority Date: 03/31/2006
• Status: Abandoned Application

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Takano, Yasuo, Yamamoto, Hidekazu, Saisho, Keiji
• Application Number:
  US11/729,904
• Publication Number:
  US 20070231684A1
• Time in Patent Office: Days
• US Class Current: 429/161
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 2004/021 Physical characteristics, e.g. porosity, surface area
• CPC Class Codes: H01M 4/0471 involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis
• CPC Class Codes: H01M 4/1395 of electrodes based on metals, Si or alloys
• CPC Class Codes: H01M 4/386 Silicon or alloys based on silicon
• CPC Class Codes: H01M 4/621 Binders
• CPC Class Codes: H01M 4/622 being polymers
• CPC Class Codes: H01M 50/119 Metals
• CPC Class Codes: H01M 50/124 having a layered structure
• CPC Class Codes: H01M 50/534 characterised by the material of the leads or tabs
• CPC Class Codes: H01M 50/54 Connection of several leads or tabs of plate-like electrode stacks, e.g. electrode pole straps or bridges
• 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 lithium secondary battery includes: a plurality of sheets of a positive electrode; at least one sheet of a negative electrode; a separator disposed between each of the positive electrode sheets and the negative electrode sheet; an electrode assembly (20) including the positive electrode, the negative electrode, and the separators; a battery case for accommodating the electrode assembly; and positive electrode current collector tabs (1), attached to individual sheets of the positive electrode, for connecting the sheets of the positive electrode to a positive electrode terminal portion of the battery case. The electrode assembly (20) is formed so that the plurality of sheets of positive electrode and the at least one sheet of the negative electrode are stacked with the separators interposed therebetween. In the electrode assembly in which the electrodes are stacked, the positive electrode current collector tabs are disposed staggered at a plurality of locations.

Claims

1. A lithium secondary battery comprising:

a plurality of sheets of a positive electrode;

at least one sheet of a negative electrode;

a separator disposed between each positive electrode sheet and the at least one sheet of negative electrode;

an electrode assembly comprising the plurality of sheets of the positive electrode, the at least one sheet of the negative electrode, and the separator, in which the plurality of sheets of positive electrode and the at least one sheet of the negative electrode are stacked with the separators interposed therebetween;

a battery case for accommodating the electrode assembly; and

positive electrode current collector tabs, attached to individual sheets of the positive electrode, for connecting the sheets of the positive electrode to a positive electrode terminal portion of the battery case, the positive electrode current collector tabs being disposed staggered at a plurality of locations in the electrode assembly in which the electrodes are stacked.

2. The lithium secondary battery according to claim 1, wherein, in the electrode assembly in which the electrodes are stacked, positive electrode current collector tabs are overlapped and the number that are overlapped at a same location is three or less.

3. The lithium secondary battery according to claim 1, wherein, in the electrode assembly in which the electrodes are stacked, the at least one sheet of the negative electrode is folded and overlapped alternately and the sheets of the positive electrode are disposed between overlapping surfaces of the negative electrode, whereby the positive electrode and the negative electrode are stacked.

4. The lithium secondary battery according to claim 2, wherein, in the electrode assembly in which the electrodes are stacked, the at least one sheet of the negative electrode is folded and overlapped alternately and the sheets of the positive electrode are disposed between overlapping surfaces of the negative electrode, whereby the positive electrode and the negative electrode are stacked.

5. The lithium secondary battery according to claim 1, wherein, in the electrode assembly in which the electrodes are stacked, the positive electrode is not disposed on an outer side of a folded portion of the negative electrode.

6. The lithium secondary battery according to claim 2, wherein, in the electrode assembly in which the electrodes are stacked, the positive electrode is not present on an outer side of a folded portion of the negative electrode.

7. The lithium secondary battery according to claim 3, wherein, in the electrode assembly in which the electrodes are stacked, the positive electrode is not present on an outer side of a folded portion of the negative electrode.

8. The lithium secondary battery according to claim 4, wherein, in the electrode assembly in which the electrodes are stacked, the positive electrode is not present on an outer side of a folded portion of the negative electrode.

9. The lithium secondary battery according to claim 1, wherein the negative electrode contains silicon as an active material.

10. The lithium secondary battery according to claim 2, wherein the negative electrode contains silicon as an active material.

11. The lithium secondary battery according to claim 7, wherein the negative electrode contains silicon as an active material.

12. The lithium secondary battery according to claim 8, wherein the negative electrode contains silicon as an active material.

13. The lithium secondary battery according to claim 9, wherein the negative electrode comprises a negative electrode current collector and a negative electrode mixture layer sintered on the negative electrode current collector, the negative electrode mixture layer containing a negative electrode binder and an active material containing silicon.

14. The lithium secondary battery according to claim 12, wherein the negative electrode comprises a negative electrode current collector and a negative electrode mixture layer sintered on the negative electrode current collector, the negative electrode mixture layer containing a negative electrode binder and an active material containing silicon.

15. The lithium secondary battery according to claim 13, wherein the negative electrode binder comprises a polyimide.

16. The lithium secondary battery according to claim 14, wherein the negative electrode binder comprises a polyimide.

17. The lithium secondary battery according to claim 1, wherein the battery case is formed of aluminum, an aluminum alloy or an aluminum laminate film.

18. The lithium secondary battery according to claim 4, wherein the battery case is formed of aluminum, an aluminum alloy or an aluminum laminate film.

19. The lithium secondary battery according to claim 12, wherein the battery case is formed of aluminum, an aluminum alloy or an aluminum laminate film.

20. The lithium secondary battery according to claim 16, wherein the battery case is formed of aluminum, an aluminum alloy or an aluminum laminate film.