Electrode assembly of stair-like structure

• US 9,318,733 B2
• Filed: 03/15/2013
• Issued: 04/19/2016
• Est. Priority Date: 12/27/2012
• Status: Active Grant

• Current Assignee: LG Energy Solution Limited (LG Corporation)
• Original Assignee: LG Chem Limited (LG Corporation)
• Inventors: Kwon, Sungjin, Kim, Ki Woong, Ahn, Soonho, Kim, Dong-Myung, Kim, Young Hoon, Yoon, Sunghan, Ryu, Seungmin
• Primary Examiner(s): DOUYETTE, KENNETH J
• Application Number:
  US13/837,833
• Publication Number:
  US 20140186685A1
• Time in Patent Office: 1,131 Days
• Field of Search: 429/160, 429/162, 429/163, 429/152, 429/130, 429/137, 429/127, 296/231, 219/200
• US Class Current: 1/1
• CPC Class Codes: H01M 10/0413 Large-sized flat cells or batteries for motive or stationary systems with plate-like electrodes
• CPC Class Codes: H01M 10/0436 Small-sized flat cells or batteries for portable equipment
• CPC Class Codes: H01M 10/0459 Cells or batteries with folded separator between plate-like electrodes
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/0585 of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
• CPC Class Codes: H01M 50/463 Separators, membranes or diaphragms characterised by their shape
• 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

Disclosed herein is an electrode assembly mounted in a battery case of a secondary battery. The electrode assembly is configured to have a structure in which a cathode and an anode are stacked in a state in which a separator plate is disposed between the cathode and the anode. The electrode assembly includes an even number of unit cells, each of the unit cells having a structure in which the uppermost electrode plate and the lowermost electrode plate have the same polarity. The electrode assembly has a stair-like structure.

Claims

1. A lithium secondary battery comprising:

an electrode assembly including;

an even number of unit cells, each of the unit cells having a structure in which electrode plates having opposite polarities are stacked in a height direction on the basis of a plane in a state in which a separator plate is disposed between the electrode plates, an uppermost electrode plate and a lowermost electrode plate have the same polarity, and electrode tabs protrude from the electrode plates, and

a single, monolithic sheet type separation film to cover one major surface, another major surface, and sides of each of the unit cells, which constitute an electrode tab non-formation region,

wherein the unit cells are stacked in the height direction on the basis of the plane such that the electrode plates having opposite polarities face each other in a state in which the separation film is disposed between the electrode plates,

wherein at least two of the stacked unit cells have different sizes, whereby the electrode assembly has a stair-like structure, and

wherein the separation film is disposed in contact with the major surface, the another major surface, and the sides of each of the unit cells,

wherein the electrode assembly is mounted in a battery case in a sealed state such that the electrode assembly is impregnated with an electrolyte.

2. The lithium secondary battery according to claim 1, wherein a larger of the electrode plates disposed adjacent to each other in a state in which the separation film is disposed between the electrode plates is an anode plate.

3. The lithium secondary battery according to claim 1, wherein a larger of the electrode plates disposed adjacent to each other in a state in which the separation film is disposed between the electrode plates is a cathode plate.

4. The lithium secondary battery according to claim 1, wherein a lowermost electrode plate of a lowermost one of the stacked unit cells is an anode plate.

5. The lithium secondary battery according to claim 1, wherein a lowermost electrode plate of a lowermost one of the stacked unit cells is a cathode plate.

6. The lithium secondary battery according to claim 5, wherein cathode slurry is present only on one major surface of the lowermost cathode plate contacting the separator plate.

7. The lithium secondary battery according to claim 6, wherein the cathode slurry is present only on a region of the one major surface of the cathode plate corresponding to one major surface of the anode plate stacked in a state in which the separator plate is disposed between the cathode plate and the anode plate.

8. The lithium secondary battery according to claim 1, wherein one or more unit cells are stacked such that electrode plates having opposite polarities face each other in a state in which the separation film is disposed between the electrode plates in a direction opposite to the height direction symmetrically or asymmetrically to the unit cells stacked in the height direction on the basis of the plane.

9. The lithium secondary battery according to claim 1, wherein the stair-like structure is formed at the electrode tab non-formation region.

10. The lithium secondary battery according to claim 1, wherein each of the electrode plates is formed in the shape of a parallelepiped having an overall width corresponding to a length of an electrode tab formation region, an overall length corresponding to a length of the electrode tab non-formation region, and an overall height corresponding to a height of each of the electrode plates.

11. The lithium secondary battery according to claim 10, wherein each of the electrode plates is formed in the shape of a rectangular parallelepiped having the overall width smaller than the overall length, and the overall height smaller than the overall width.

12. The lithium secondary battery according to claim 10, wherein each of the electrode plates is formed in the shape of a rectangular parallelepiped having the overall length and the overall width equal to each other and the overall height smaller than the overall width.

13. The lithium secondary battery according to claim 10, wherein each of the electrode plates is formed in the shape of a regular hexahedron having the overall length, the overall width, and the overall height equal to one another.

14. The lithium secondary battery according to claim 10, wherein at least one corner of each of the electrode plates is curved.

15. The lithium secondary battery according to claim 1, wherein the electrode assembly includes at least one additional stair-like structure, the stair-like structures having the same step heights and different widths.

16. The lithium secondary battery according to claim 15, wherein the width, the height, or the width and the height is configured based on curvature of a device in which a battery cell having the electrode assembly mounted therein is installed.

17. The lithium secondary battery according to claim 1, wherein an end of the separation film is fixed by thermal welding or taping in a state in which the stacked electrode groups are covered by the separation film.

18. The lithium secondary battery according to claim 1, wherein the electrode assembly includes at least one additional stair-like structure, the stair-like structures having different widths and heights.

19. A device comprising one or more lithium secondary batteries according to claim 1 as a power source.

20. The device according to claim 19, wherein the device is selected from among a mobile phone, a portable computer, a smartphone, a smart pad, a netbook computer, a light electronic vehicle, an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, and a power storage unit.

21. The lithium secondary battery according to claim 1, wherein the unit cells are stacked in the shape of a frustum of a quadrangular pyramid.

22. The lithium secondary battery according to claim 1, wherein the unit cells are stacked in the shape of a frustum of an octagonal pyramid.