Stepped electrode group stack

• US 9,954,203 B2
• Filed: 03/18/2013
• Issued: 04/24/2018
• Est. Priority Date: 03/08/2013
• Status: Active Grant

• Current Assignee: LG Energy Solution Limited (LG Corporation)
• Original Assignee: LG Chem Limited (LG Corporation)
• Inventors: Kwon, Sungjin, Kim, Ki Woong, Kim, Dong-Myung
• Primary Examiner(s): D'Aniello, Nicholas P
• Application Number:
  US13/845,709
• Publication Number:
  US 20140255756A1
• Time in Patent Office: 1,863 Days
• CPC Class Codes: H01M 10/0436 Small-sized flat cells or batteries for portable equipment
• 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: 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 group stack including a plurality of electrode groups, each of which includes a cathode, an anode, and a first separator disposed between the cathode and the anode, and a second separator disposed between the electrode groups, wherein the electrode groups are stacked in a height direction on the basis of a plane, some or all of the electrode groups have different areas of opposite stack surfaces at a stack interface therebetween, and the electrode group stack includes an electrode group satisfying equation (1): T≥(Tsum×0.5) (1), where T indicates a thickness of an arbitrary electrode group and Tsum indicates a sum of thicknesses of the electrode groups constituting the electrode group stack.

Claims

1. An electrode group stack comprising:

a plurality of electrode groups, each of which comprises a cathode, an anode, and a first separator disposed between the cathode and the anode; and

a second separator disposed between the electrode groups, wherein;

the electrode groups are stacked in a height direction on the basis of a plane,

some or all of the electrode groups have different areas of opposite stack surfaces at a stack interface therebetween to form a step at the stack interface, the step being defined by a first step surface that extends in the height direction and a second step surface that extends in a direction perpendicular to the height direction of adjacent electrode groups, and

the electrode group stack comprises an electrode group satisfying equation (1);

T≥

(Tsum×

0.5) 

 

(1)

where T indicates a thickness of an electrode group having the largest area of the stack surface and Tsum indicates a sum of thicknesses of the electrode groups constituting the electrode group stack;

wherein each of the electrode groups is a stacked type electrode group comprising a cathode plate, an anode plate, and a first plate-shaped separator disposed between the cathode plate and the anode plate, the cathode plate and the anode plate being stacked in the height direction on the basis of the plane in a state in which a separator plate is between the cathode plate and the anode plate;

wherein the second separator is a one-unit separation sheet that is disposed between the stacked type electrode groups to cover a top, a bottom, and sides of each of the stacked type electrode groups at which electrode terminals are not formed and to cover substantially an entire outer circumference of the electrode group stack; and

wherein the second separator is disposed in contact with the first and second step surfaces at the respective steps.

2. The electrode group stack according to claim 1, wherein the separation sheet is disposed in contact with the sides of the stacked type electrode groups.

3. The electrode group stack according to claim 1, wherein one of the stacked type electrode groups having the largest area of the stack surface is an S stacked type electrode group, an uppermost electrode and a lowermost electrode of which have the same polarity.

4. The electrode group stack according to claim 3, wherein the S stacked type electrode group is an SA stacked type electrode group, an uppermost electrode and a lowermost electrode of which are anodes.

5. The electrode group stack according to claim 3, wherein the S stacked type electrode group is an SC stacked type electrode group, an uppermost electrode and a lowermost electrode of which are cathodes.

6. The electrode group stack according to claim 1, wherein one of the stacked type electrode groups having the largest area of the stack surface is a D stacked type electrode group, an uppermost electrode and a lowermost electrode of which have different polarities.

7. The electrode group stack according to claim 6, wherein the D stacked type electrode group has a minimum thickness of 0.3 mm.

8. The electrode group stack according to claim 1, wherein the electrode groups stacked on the electrode group having the largest area of the stack surface satisfy equation (2):

Ta=n×

Tb 

 

(2)

where Ta and Tb each indicate a thickness of an arbitrary electrode group selected from among the electrode groups stacked on the electrode group having the largest area of the stack surface, and n indicates a natural number.

9. The electrode group stack according to claim 8, wherein the arbitrary electrode groups comprises S stacked type electrode groups, D stacked type electrode groups, or a combination of the S stacked type electrode groups and the D stacked type electrode groups.

10. The electrode group stack according to claim 1, wherein the cathode has a cathode slurry layer formed only at an area of the cathode facing the anode.

11. The electrode group stack according to claim 1, wherein the anode has an anode slurry layer formed only at an area of the anode facing the cathode.

12. The electrode group stack according to claim 1, wherein the electrode group stack has a maximum thickness of 5.5 mm.

13. The electrode group stack according to claim 1, wherein one of the electrodes opposite to each other at the interface between the electrode groups, which has a larger opposite area, is an anode.

14. The electrode group stack according to claim 1, wherein one of the electrodes opposite to each other at the interface between the electrode groups, which has a larger opposite area, is a cathode.

15. The electrode group stack according to claim 1, wherein the stacked type electrode groups include a first unit cell configured to have a laminated structure in which a cathode plate, an anode plate, and separator plates are stacked such that (1) the cathode plate or the anode plate and (2) one of the separator plates are located at outermost sides of the stacked type electrode group.

16. The electrode group stack according to claim 15, wherein the stacked type electrode groups include a second unit cell configured to have a laminated structure in which a cathode plate, an anode plate, and separator plates are stacked such that the separator plates are located at outermost sides of the stacked type electrode group.

17. The electrode group stack according to claim 15, wherein one of separator plates constitutes a second separator.

18. The electrode group stack according to claim 1, wherein the electrode groups are stacked in the height direction and in a direction opposite to the height direction on the basis of the stacked type electrode group having the largest area of the stack surface.

19. The electrode group stack according to claim 1, wherein the number of the electrode groups is even.

20. The electrode group stack according to claim 1, wherein the number of the electrode groups is odd.

21. A lithium secondary battery comprising an electrode group stack according to claim 1, wherein the electrode group stack is mounted in a battery case.

22. The lithium secondary battery according to claim 21, wherein the battery case is formed of a laminate sheet comprising a resin layer and a metal layer or a metal container.

23. The lithium secondary battery according to claim 21, wherein the battery case is provided with a receiving part having an internal structure corresponding to an external structure of the electrode group stack.

24. The lithium secondary battery according to claim 21, wherein the lithium secondary battery is a lithium ion battery.

25. The lithium secondary battery according to claim 21, wherein the lithium secondary battery is a lithium polymer battery.

26. The lithium secondary battery according to claim 21, wherein the lithium secondary battery is a lithium ion polymer battery.