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 a collector plate comprising first and second collector plates enmeshed together with the non-coating portion therebetween, wherein the first collector plate comprises a plurality of first protrusions, the second collector plate comprises a plurality of second protrusions enmeshed with the plurality of first protrusions, 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; 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; 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; and wherein the first weld and the second weld together form a serpentine weld. 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 a collector plate comprising first and second collector plates enmeshed together with the non-coating portion therebetween, wherein the first collector plate comprises a plurality of first protrusions, the second collector plate comprises a plurality of second protrusions enmeshed with the plurality of first protrusions, 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; 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; 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; and wherein the first weld and the second weld together form a serpentine weld.