A secondary battery is disclosed. In one embodiment, the secondary battery includes i) an electrode assembly comprising upper and lower surfaces opposing each other, ii) a container configured to receive the electrode assembly via an opening defined at one end thereof, iii) a cap assembly configured to close the opening of the container, wherein an electrolyte injection hole is defined in the cap assembly, and wherein the electrolyte injection hole is configured to receive electrolyte and iv) an insulation case configured to be received by the container and being interposed between the cap assembly and the electrode assembly, wherein a first electrolyte permeation passage is formed between an outer surface of the insulation case and an inner surface of the container, and wherein the first electrolyte permeation passage is configured to expedite the permeation of the received electrolyte into the lower surface of the electrode assembly.