Abstract: Provided is a lithium secondary battery including: a positive electrode plate which is a lithium complex oxide sintered plate; a negative electrode layer; a separator; an electrolytic solution; and a pair of exterior films having outer peripheral edges sealed with each other to form an internal space that accommodates the battery elements, wherein the portions of the negative electrode layer and the separator corresponding to the outer extension of the battery is deviated toward the positive electrode plate side from the portions of the negative electrode layer and the separator corresponding to the body of the battery.

Abstract: The present invention relates to a secondary battery which is capable of improving safety. As an example, a secondary battery which comprises an electrode assembly; a case which accommodates the electrode assembly; a cap assembly which is coupled to an upper portion of the case, and a gasket which is interposed between the cap assembly and the case, wherein the cap assembly comprises a cap-up, a safety vent which is installed at a lower portion of the cap-up, a cap-down which is installed at a lower portion of the safety vent, an insulator which is interposed between the safety vent and the cap-down, and a sub-plate which is located on a lower surface of the cap-down, and an insulation layer is formed on one surface of the safety vent, is disclosed.

Abstract: An electrolyte level measuring device for a vented lead acid battery and a method of monitoring an electrolyte level is provided. The measuring device includes an elongated body. A stop member extends outwardly from the elongated body, the stop member being sized larger than an opening in the vented lead acid battery. At least one projection extends orthogonally from the elongated body.