Stepped electrode assembly

• US 10,026,994 B2
• Filed: 09/17/2015
• Issued: 07/17/2018
• Est. Priority Date: 11/13/2012
• Status: Active Grant

• Current Assignee: LG Energy Solution Limited (LG Corporation)
• Original Assignee: LG Chem Limited (LG Corporation)
• Inventors: Kwon, Sungjin, Kim, Dong-Myung, Kim, Ki-Woong, Ahn, Soon-Ho
• Primary Examiner(s): Cano, Milton I
• Assistant Examiner(s): Zhang, Haixia
• Application Number:
  US14/857,150
• Publication Number:
  US 20160028126A1
• Time in Patent Office: 1,034 Days
• Field of Search: None
• 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 10/058 Construction or manufacture
• 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 2004/021 Physical characteristics, e.g. porosity, surface area
• CPC Class Codes: H01M 2004/025 with shapes other than plane or cylindrical
• CPC Class Codes: H01M 2010/4292 Aspects relating to capacity ratio of electrodes/electrolyte or anode/cathode
• CPC Class Codes: H01M 2220/30 Batteries in portable systems, e.g. mobile phone, laptop
• CPC Class Codes: H01M 4/13 Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
• CPC Class Codes: H01M 4/70 characterised by shape or form
• CPC Class Codes: H01M 50/46 Separators, membranes or diaphragms characterised by their combination with electrodes
• 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: H01M 6/42 Grouping of primary cells into batteries H01M6/40 takes precedence
• CPC Class Codes: H01M 6/46 of flat cells
• 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: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

Disclosed herein is an electrode assembly including two or more electrode plates, each of which has electrode tabs, and a separator plate disposed between the electrode plates and/or a one-unit separation sheet disposed between the electrode plates to cover side surfaces of the electrode plates, which constitute an electrode tab non-formation region, wherein the electrode plates are stacked in a height direction on the basis of a plane such that the electrode plates having opposite polarities face each other in a state in which the separator plate and/or the separation sheet is disposed between the electrode plates, a stack constituted by the electrode plates includes electrode plates having different sizes, and an absolute value of the difference in thickness between the electrode plates having different sizes facing each other is 0 to 79 μm.

Claims

1. An electrode assembly comprising:

two or more unit cells, each unit cell including;

two or more electrode plates, each of which has at least one electrode tab, and

a separator plate disposed between adjacent electrode plates,

wherein the electrode plates are stacked in a height direction on the basis of a plane such that the electrode plates having opposite polarities face each other in a state in which the separator plate is disposed between adjacent electrode plates, and

a one-unit separation sheet disposed between adjacent unit cells to cover major and side surfaces of all of the unit cells, which constitute an electrode tab non-formation region,

wherein at least two of the unit cells have different sizes, and the unit cells are stacked in the height direction,

wherein the electrode plates comprise cathode plates, each of which has a cathode material layer formed on a cathode current collector, and anode plates, each of which has an anode material layer formed on an anode current collector,

the anode plates comprise single-sided anode plates, each of which has the anode material layer formed on only one major surface of the anode current collector, and double-sided anode plates, each of which has the anode material layer formed on opposite major surfaces of the anode current collector,

the anode current collector of each of the single-sided anode plates has a larger thickness than that of each of the double-sided anode plates,

wherein a larger-sized one of the electrode plates having different sizes facing each other is a first anode plate of the anode plates,

wherein the anode material layer is formed at opposite major surfaces of the first anode plate facing a first cathode plate of the cathode plates in a state in which the separator plate or the separation sheet is disposed between the first anode plate and the first cathode plate, and wherein the anode material layer is formed at only a region of the first anode plate corresponding to a region of the first cathode plate facing the first anode plate at which a cathode material layer is formed,

wherein the cathode plates comprise single-sided cathode plates, each of which has the cathode material layer formed on only one major surface of the cathode current collector, and double-sided cathode plates, each of which has the cathode material layer formed on opposite major surfaces of the cathode current collector, and

wherein a cathode current collector of each of the single-sided cathode plates has a larger thickness than that of each of the double-sided cathode plates.

2. The electrode assembly according to claim 1, wherein an N/P ratio of differently sized cathode and anode plates of the electrode plates is 1.0 to 1.1.

3. The electrode assembly according to claim 1, wherein a ratio of the thickness of the cathode current collector of each of the single-sided cathode plates to the thickness of the cathode current collector of each of the double-sided cathode plates is 2.5:

1 to 1.5;

1.

4. The electrode assembly according to claim 1, wherein each of the single-sided cathode plates has a maximum thickness of 87 μ

m to 92 μ

m.

5. The electrode assembly according to claim 1, wherein each of the double-sided cathode plates has a maximum thickness of 128 μ

m to 133 μ

m.

6. The electrode assembly according to claim 1, wherein each of the single-sided cathode plates has a minimum thickness of 70 μ

m to 74 μ

m.

7. The electrode assembly according to claim 1, wherein each of the double-sided cathode plates has a minimum thickness of 91 μ

m to 99 μ

m.

8. The electrode assembly according to claim 1, wherein each of the single-sided cathode plates has a loading level of 16 mg/cm² to 22 mg/cm².

9. The electrode assembly according to claim 1, wherein each of the double-sided cathode plates has a loading level of 32 mg/cm² to 44 mg/cm².

10. The electrode assembly according to claim 1, wherein a ratio of the thickness of the anode current collector of each of the single-sided anode plates to the thickness of the anode current collector of each of the double-sided anode plates is 2.5:

1 to 1.5;

1.

11. The electrode assembly according to claim 1, wherein each of the single-sided anode plates has a maximum thickness of 86 μ

m to 91 μ

m.

12. The electrode assembly according to claim 1, wherein each of the double-sided anode plates has a maximum thickness of 139 μ

m to 149 μ

m.

13. The electrode assembly according to claim 1, wherein each of the single-sided anode plates has a minimum thickness of 67 μ

m to 70 μ

m.

14. The electrode assembly according to claim 1, wherein each of the double-sided anode plates has a minimum thickness of 101 μ

m to 108 μ

m.

15. The electrode assembly according to claim 1, wherein each of the single-sided anode plates has a loading level of 7.7 mg/cm² to 10.5 mg/cm².

16. The electrode assembly according to claim 1, wherein each of the double-sided anode plates has a loading level of 15.4 mg/cm² to 21 mg/cm².

17. The electrode assembly according to claim 1, wherein a first single-sided anode plate of the single-sided anode plates is stacked on a lowermost end of the electrode assembly and the anode material layer is formed on only one major surface of the first single-sided anode plate facing an adjacent cathode plate of the cathode plates in a state in which the separator plate or the separation sheet is disposed between the first single-sided anode plate and the adjacent cathode plate.

18. The electrode assembly according to claim 17, wherein the anode material layer is formed on only a region of the first single-sided anode plate corresponding to a region of the adjacent cathode plate facing the first single-sided anode plate at which the cathode material layer of the adjacent cathode plate is formed.

19. The electrode assembly according to claim 1, wherein a first single-sided cathode plate of the single-sided cathode plates is stacked on a lowermost end of the electrode assembly, the cathode material layer is formed on only one major surface of the first single-sided cathode plate facing an adjacent anode plate of the anode plates in a state in which the separator plate or the separation sheet is disposed between the first single-sided cathode plate and the adjacent anode plate, and the cathode material layer is formed on only a region of the first single-sided cathode plate corresponding to a region of the adjacent anode plate facing the first single-sided cathode plate at which the anode material layer of the adjacent anode plate is formed.

20. The electrode assembly according to claim 1, wherein at least one corner of the electrode plates is curved.

21. The electrode assembly according to claim 1, wherein the separation sheet is disposed in contact with the side surfaces of the electrode plates of the unit cells.

22. The electrode assembly according to claim 1, wherein a thickness ratio of adjacent ones of the electrode plates having different sizes among of all of the unit cells is increased in the height direction.

23. The electrode assembly according to claim 1, wherein an absolute value of the difference in thickness between the electrode plates having different sizes facing each other is 0 to 79 μ

m.

24. A lithium secondary battery comprising the electrode assembly according to claim 1.