Secondary battery

1. A secondary battery comprising:

a case;

an electrode assembly housed in the case and comprising a first electrode, a second electrode, and a separator between the first electrode and the second electrode, the first electrode having a coating portion coated with a first active material and a non-coating portion absent the first active material; and

first and second collector plates enmeshed together with the non-coating portion therebetween,

wherein:

the first collector plate comprises a first plate and a first protrusion, the first protrusion extending lengthwise from the first plate and extending with a first step height from the first plate;

the second collector plate comprises a second plate and a second protrusion, the second protrusion extending lengthwise from the second plate and extending with a second step height from the second plate;

the non-coating portion is between the first protrusion and the second protrusion;

the non-coating portion is coupled to both the first protrusion and the second protrusion by a weld between the first and second protrusions;

a first portion of the weld has a length extending in a direction along lengthwise edge portions of the first protrusion and the second protrusion; and

the first portion of the weld has a width that is less than the length of the first portion of the weld.

2. The secondary battery of claim 1 , wherein the weld is a butt weld.

3. The secondary battery of claim 1 , wherein the weld is at an end of the non-coating portion.

4. The secondary battery of claim 1 , wherein the non-coating portion extends from the coating portion with a distance greater than the first step height or the second step height.

5. The secondary battery of claim 1 , wherein the non-coating portion is welded to the first and second collector plates in a state in which an end of the non-coating portion is coplanar with the first and second collector plates.

6. The secondary battery of claim 1 , wherein the non-coating portion is welded to the first and second collector plates in a state in which an end of the non-coating portion extends through the first and second collector plates.

7. The secondary battery of claim 1 , wherein:

the first collector plate comprises a plurality of first protrusions, the plurality of first protrusions comprising the first protrusion,

the second collector plate comprises a plurality of second protrusions enmeshed with the plurality of first protrusions, the plurality of second protrusions comprising the second protrusion, and

one of the plurality of first protrusions and a corresponding one of the plurality of second protrusions are enmeshed together with the non-coating portion therebetween.

8. The secondary battery of claim 1 , wherein:

the first electrode is wound together with the second electrode and the separator to form a jellyroll structure,

the jellyroll structure comprises the non-coating portion, the non-coating portion located at a first end of the electrode assembly and between the enmeshed first and second collector plates, and

the first collector plate further comprises a plurality of first protrusions extending from the first plate with the first step height from the first plate, the first plurality of protrusions comprising the first protrusion.

9. The secondary battery of claim 8 , wherein:

the first plate has a surface abutting the first end of the electrode assembly, and

the plurality of first protrusions are located within the non-coating portion.

10. The secondary battery of claim 8 , wherein:

the plurality of first protrusions define a plurality of grooves, and

the non-coating portion comprises a plurality of portions partitioned by and located in the plurality of grooves.

11. The secondary battery of claim 8 , wherein:

the second collector plate further comprises a plurality of second protrusions extending from the second plate with the second step height from the second plate, the second plurality of protrusions comprising the second protrusion.

12. The secondary battery of claim 11 , wherein:

the first plate has a surface abutting the first end of the electrode assembly,

the plurality of first protrusions are located within the non-coating portion,

the second plate has a surface abutting the first end of the electrode assembly, and

the plurality of second protrusions are located within the non-coating portion.

13. The secondary battery of claim 11 , wherein:

the plurality of first protrusions define a plurality of first grooves,

the non-coating portion comprises a plurality of portions first partitioned by and located in the plurality of first grooves,

the plurality of second protrusions define a plurality of second grooves, and

the plurality of portions are second partitioned by and located in the plurality of second grooves.

14. The secondary battery of claim 11 , wherein:

the non-coating portion comprises a first set of non-coating portions and a second set of non-coating portions,

the first set of the non-coating portions is located between a first one of the plurality of first protrusions and a corresponding first one of the plurality of second protrusions, and

the second set of the non-coating portions is located between a second one of the plurality of first protrusions and a corresponding second one of the plurality of second protrusions.

15. The secondary battery of claim 14 , wherein:

the first set of the non-coating portions is welded to both the first one of the plurality of first protrusions and the corresponding first one of the plurality of second protrusions by a first weld, and

the second set of the non-coating portions is welded to both the second one of the plurality of first protrusions and the corresponding second one of the plurality of second protrusions by a second weld,

wherein at least one of the first weld or the second weld comprise the weld.

16. The secondary battery of claim 15 , wherein the first weld and the second weld together form a serpentine weld.