SECONDARY BATTERY

A secondary battery includes a case including an accommodation part and having a width direction (X-axis direction) and a height direction (Y-axis direction) defined, an electrode assembly accommodated in the accommodation part, a first current collecting plate on the electrode assembly, an injection member on the first current collecting plate, and a cap assembly on the case, wherein the electrode assembly includes a first electrode, a second electrode, and a separator therebetween, the electrode assembly includes a hollow part, the first current collecting plate includes a first hole overlapping the hollow part, the injection member includes an inlet and an outlet, the injection member includes a second hole overlapping the first hole, the injection member includes a protrusion part in the first hole, the protrusion part spaced apart from the first current collecting plate, and a width of the protrusion part changes while extending from the inlet to the outlet.