Patent ID: 7700231

Claim:
A battery comprising: an electrode assembly comprising a positive electrode plate, a negative electrode plate and a separator wound or laminated together, core materials of the positive and negative electrode plates being bared at ends of the electrode assembly; a cylindrical outer case having a bottom connected to an end face of the electrode assembly to serve as a battery terminal; electrolyte impregnated in the electrode assembly; and a lid connected to another end face of the electrode assembly and attached to the outer case, wherein the lid includes a cylindrical portion, a connecting part in one piece therewith that engages with and connects to a bottom part of an outer case of another battery to be connected, a hole configured to receive the electrolyte into the battery, and a safety structure that releases gas in response to a build-up of internal pressure, the lid is fixed to the outer case of the battery by a fixing groove formed on the lid and the outer case at a position where a gasket is interposed between the outer case of the battery and the cylindrical portion of the lid, and the lid directly contacts and is directly welded to the bared portion of the core material of one of the electrode plates of the electrode assembly.