Rechargeable battery

1. A rechargeable battery comprising:

an electrode assembly with a non-coated area tab that protrudes to one side of a coated area;

a case defining an opening at one side thereof to receive the electrode assembly;

a cap plate coupled and welded to the opening, the cap plate having a length and a width with a first end and a second end at opposite ends of the width, wherein the first end and the second end of the cap plate are each welded to the case at respective side edges where the cap plate and case intersect;

an electrode terminal in the cap plate and electrically connected to the non-coated area tab; and

an insulation sheet for insulating the electrode assembly extending along the length of the cap plate between the cap plate and the electrode assembly, and comprising a first bend extending along and adjacent to the first end of the cap plate and a second bend extending along and adjacent to the second end of the cap plate,

wherein the insulation sheet comprises spacing portions distanced from respective side edges, and

wherein the spacing portions extend along the entire length of the first and second ends of the cap plate, respectively, and are on the first bend and the second bend, respectively.

2. The rechargeable battery of claim 1 , wherein the insulation sheet comprises:

an upper portion between the cap plate and the electrode assembly; and

side portions bent from the upper portion at the first and second ends of the cap plate, respectively, and between side surfaces of the electrode assembly and the case, and

the spacing portions connecting the upper portion and the side portions.

3. The rechargeable battery of claim 2 , further comprising a top insulator between the coated area and the insulation sheet and between the coated area and the electrode terminal,

wherein the top insulator comprises:

a plate portion on the electrode assembly, and

expansion portions extending toward the side edges.

4. The rechargeable battery of claim 3 , wherein the non-coated area tab extends around the expansion portion to be welded to the electrode terminal, and

the spacing portions are distanced toward the expansion portions from the side edges.

5. The rechargeable battery of claim 4 , wherein one of the spacing portions is supported by the non-coated area tab that surrounds a respective expansion portion.

6. A rechargeable battery comprising:

an electrode assembly with a non-coated area tab that protrudes to one side of a coated area;

a case defining an opening at one side thereof to receive the electrode assembly;

a cap plate coupled and welded to the opening, the cap plate having a length and a width with a first end and a second end at opposite ends sides of the width, wherein the first end and the second end of the cap plate are each welded to the case at respective side edges where the cap plate and case intersect;

an electrode terminal in the cap plate and electrically connected to the non-coated area tab; and

an insulation sheet for insulating the electrode assembly extending along the length of the cap plate between the cap plate and the electrode assembly, and comprising a first bend extending along and adjacent to the first end of the cap plate and a second bend extending along and adjacent to the second end of the cap plate,

a top insulator between the coated area and the insulation sheet and between the coated area and the electrode terminal,

wherein the insulation sheet comprises:

an upper portion between the cap plate and the electrode assembly; and

side portions bent from the upper portion at the first and second ends of the cap plate, respectively, and between side surfaces of the electrode assembly and the case, and

spacing portions distanced from respective side edges where the cap plate and case intersect, the spacing portions connecting the upper portion and the side portions;

wherein the spacing portions are on the first bend and the second bend, respectively;

wherein the top insulator comprises:

a plate portion on the electrode assembly, and

expansion portions extending toward the side edges;

wherein, in the insulation sheet, the upper portion defines:

a first internal electrolyte injection opening corresponding to an electrolyte injection opening in the cap plate;

a first internal vent hole corresponding to a vent hole in the cap plate; and

an internal terminal hole corresponding to the electrode terminal.

7. The rechargeable battery of claim 6 , wherein the top insulator comprises:

a second internal electrolyte injection opening corresponding to the first internal electrolyte injection opening; and

a second internal vent hole corresponding to the first internal vent hole.

8. The rechargeable battery of claim 2 , wherein, in a cross-sectional view perpendicular to the length of the cap plate, the spacing portions are distanced from their respective side edges by a radius of curvature in which the side edge is viewed as the center of curvature.

9. The rechargeable battery of claim 2 , wherein, in a cross-sectional view perpendicular to the length of the cap plate, each of the spacing portions along with the cap plate and the case define a respective triangular shape, in which each respective side edge defines one vertex of the respective triangular shape, the spacing portions each define one side of the respective triangular shape and the cap plate and the case define the remaining two sides of each respective triangular shape.

10. The rechargeable battery of claim 2 , wherein, in a cross-sectional view perpendicular to the length of the cap plate, each of the spacing portions along with the case and the cap plate define a respective quadrangular shape, in which each spacing portion defines two sides of the respective quadrangular shape and the cap plate and the case define the remaining two sides of each respective quadrangular shape.