Secondary battery

Disclosed in the present invention is a secondary battery in which retainers are coupled between a case and the uncoated portions of electrode assemblies so that the electrode assemblies and current collectors can be fixed and prevented from being separated. Disclosed in one embodiment is a secondary battery comprising: a plurality of electrode assemblies of which each has a cathode plate and an anode plate arranged with a separator therebetween, and which includes the uncoated portions of the cathode plate and the anode plate; a case in which the electrode assemblies are embedded; a cap plate coupled to the case; current collectors respectively coupled to the uncoated portions of the plurality of electrode assemblies through a plurality of coupling portions; and retainers inserted and coupled to on one side of the current collectors, wherein the retainers are coupled to the current collectors through protrusion portions having a width greater than that between the coupling portions of the current collectors.