Electrode assembly and pouch type lithium rechargeable battery having the same

• US 20070231701A1
• Filed: 03/28/2007
• Published: 10/04/2007
• Est. Priority Date: 03/28/2006
• Status: Active Grant

• Current Assignee: Samsung SDI Company Limited
• Original Assignee: Samsung SDI Company Limited
• Inventors: Lee, Sang-Ho
• Granted Patent: US 7,858,240 B2
• Time in Patent Office: Days
• US Class Current: 429/246
• CPC Class Codes: H01M 10/0436 Small-sized flat cells or batteries for portable equipment
• 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 50/126 comprising three or more layers
• CPC Class Codes: H01M 50/178 for pouch or flexible bag cells
• CPC Class Codes: H01M 50/469 tubular or cylindrical
• CPC Class Codes: H01M 50/55 on the same side of the cell
• CPC Class Codes: H01M 50/553 Terminals adapted for prismatic, pouch or rectangular cells
• CPC Class Codes: H01M 50/572 Means for preventing undesired use or discharge
• 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

The present invention relates to an electrode assembly and a pouch type lithium rechargeable battery having the same, which can minimize the total volume of a battery while maximizing a distance between electrode tabs. Insulation members cover portions of electrode tabs to prevent contact of an electrode tab with another electrode tab and electrode plate with opposite polarity. The shape of the insulation member is changed to effectively increase the distance between electrode tabs and to reduce overall thickness or width of the battery.

Claims

1. An electrode assembly comprising:

a positive electrode plate including a positive electrode coating portion and a positive electrode non-coating portion, a positive electrode active material coated on at least one side of the positive electrode coating portion;

a negative electrode plate including a negative electrode coating portion and a negative electrode non-coating portion, a negative electrode active material coated on at least one side of the negative electrode coating portion;

a separator interposed between the positive electrode plate and the negative electrode plate to insulate the positive electrode plate from the negative electrode plate;

a positive electrode tab including a positive electrode tab protrusion and a positive electrode tab body, the positive electrode tab protrusion protruding out of the positive electrode plate along a first direction, the positive electrode tab body coupled to the positive electrode non-coating portion;

a negative electrode tab including a negative electrode tab protrusion and a negative electrode tab body, the negative electrode tab protrusion protruding out of the negative electrode plate along the first direction, the negative electrode tab body coupled to the negative electrode non-coating portion;

a positive insulation member formed on the positive electrode tab covering an interface between the positive electrode tab protrusion and the positive electrode tab body, the positive insulation member including a positive insulation wide portion and a positive insulation narrow portion, the positive insulation wide portion covering a portion of the positive electrode tab protrusion, a width of the positive insulation wide portion being greater than a width of the positive insulation narrow portion; and

a negative insulation member formed on the negative electrode tab covering an interface between the negative electrode tab protrusion and the negative electrode tab body, the negative insulation member including a negative insulation wide portion and a negative insulation narrow portion, the negative insulation wide portion covering a portion of the negative electrode tab protrusion, a width of the negative insulation wide portion being greater than a width of the negative insulation narrow portion.

2. The electrode assembly as claimed in claim 1, comprised of the positive insulation wide portion being spaced apart by a first predetermined distance along the first direction from the interface between the positive electrode tab protrusion and the positive electrode tab body.

3. The electrode assembly as claimed in claim 2, comprised of the separator protruding along the first direction by a second predetermined distance from the positive electrode plate.

4. The electrode assembly as claimed in claim 2, wherein the first predetermined distance is substantially the same as the second predetermined distance.

5. The electrode assembly as claimed in claim 1, wherein the positive electrode plate, the separator, and the negative electrode plate are formed into a stack, and the stack is wound about both of the positive electrode tab and the negative electrode tab;

the wound stack having a top surface through which the positive electrode tab and the negative electrode tab protrude, and a side surface;

the side surface having a flat portion and a curved portion.

6. The electrode assembly as claimed in claim 5, wherein none of edges, which are formed along the first direction, of the positive insulation wide portion is aligned with an edge, which are formed along the first direction, of the positive insulation narrow portion, so that the positive insulation member has a shape of ‘

T’

, with the positive insulation wide portion having ‘

-’

shape and with the positive insulation narrow portion having ‘

|’

shape; and

none of edges, which are formed along the first direction, of the negative insulation wide portion is aligned with an edge, which are formed along the first direction, of the negative insulation narrow portion, so that the negative insulation member has a shape of ‘

T’

, with the negative insulation wide portion having ‘

-’

shape and with the negative insulation narrow portion having ‘

|’

shape.

7. The electrode assembly as claimed in claim 6, wherein the width of the positive insulation wide portion is greater than a width of the positive electrode body, and the width of the negative insulation wide portion is greater than a width of the negative electrode body.

8. The electrode assembly as claimed in claim 6, wherein the width of the positive insulation narrow portion is substantially the same as the width of the positive electrode tab body, and the width of the negative insulation narrow portion is substantially the same as the width of the negative electrode tab body.

9. The electrode assembly as claimed in claim 8, comprised of the stack wrapping both of the positive insulation narrow portion and the negative insulation narrow portion about the first direction.

10. The electrode assembly as claimed in claim 9, wherein the width direction of the positive insulation wide portion is substantially parallel to the flat portion of the side surface of the wound stack and one edge of the positive insulation wide portion intrudes into the curved portion of the side surface of the wound stack when viewed from the top surface of the wound stack, and the width direction of the negative insulation wide portion is substantially parallel to the flat portion of the side surface of the wound stack and one edge of the negative insulation wide portion intrudes into the curved portion of the side surface of the wound stack when viewed from the top surface of the wound stack.

11. The electrode assembly as claimed in claim 5, wherein one of edges, which are formed along the first direction, of the positive insulation wide portion is aligned with an edge, which are formed along the first direction, of the positive insulation narrow portion, so that the positive insulation member has a shape of an inverted ‘

L’

, with the positive insulation wide portion having ‘

-’

shape and with the positive insulation narrow portion having ‘

|’

shape.

12. The electrode assembly as claimed in claim 11, wherein the width direction of the positive insulation wide portion is substantially parallel to the flat portion of the side surface of the wound stack.

13. The electrode assembly as claimed in claim 12, wherein the width of the positive insulation narrow portion is substantially the same as a width of the positive electrode tab body.

14. The electrode assembly as claimed in claim 6, wherein the positive insulation wide portion and the positive insulation narrow portion are separated.

15. The electrode assembly as claimed in claim 6, wherein the positive insulation wide portion and the positive insulation narrow portion are integrally formed.

16. The electrode assembly as claimed in claim 14, comprised of the positive insulation wide portion including an insulation tape.

17. The electrode assembly as claimed in claim 16, comprised of the positive insulation narrow portion including a laminated tape.

18. The electrode assembly as claimed in claim 17, wherein each of the insulation tape and the laminated tape is made of one selected from polyphenylene sulfide (PS), polyimide (PI), and polypropylene (PP).

19. A pouch type lithium rechargeable battery comprising:

a pouch; and

an electrode assembly stored in the pouch, the electrode assembly comprising;

a positive electrode plate including a positive electrode coating portion and a positive electrode non-coating portion, a positive electrode active material coated on at least one side of the positive electrode coating portion;

a negative electrode plate including a negative electrode coating portion and a negative electrode non-coating portion, a negative electrode active material coated on at least one side of the negative electrode coating portion;

a separator interposed between the positive electrode plate and the negative electrode plate to insulate the positive electrode plate from the negative electrode plate;

a positive electrode tab including a positive electrode tab protrusion and a positive electrode tab body, the positive electrode tab protrusion protruding out of the positive electrode plate along a first direction, the positive electrode tab body coupled to the positive electrode non-coating portion;

a negative electrode tab coupled to the negative electrode non-coating portion, one end of the negative electrode tab protruding out of the negative electrode plate along the first direction; and

a positive insulation member formed on the positive electrode tab covering an interface between the positive electrode tab protrusion and the positive electrode tab body, the positive insulation member including a positive insulation wide portion and a positive insulation narrow portion, the positive insulation wide portion covering a portion of the positive electrode tab protrusion, a width of the positive insulation wide portion being greater than a width of the positive insulation narrow portion.

20. The pouch type lithium rechargeable battery as claimed in claim 19, wherein none of edges, which are formed along the first direction, of the positive insulation wide portion is aligned with an edge, which are formed along the first direction, of the positive insulation narrow portion, so that the positive insulation member has a shape of ‘

T’

, with the positive insulation wide portion having ‘

-’

shape and with the positive insulation narrow portion having ‘

|’

shape.