Patent ID: 8110303

Claim:
A lithium ion battery comprising: at least one positive electrode; at least one negative electrode made of a material capable of being doped or undoped with lithium; a polyolefin separator, wherein the unit weight of the separator is not less than 5 g/m 2 and not more than 30 g/m 2 ; a liquid or gel electrolyte containing lithium salt and an organic solvent; and only one battery case in which said at least one positive electrode, said at least one negative electrode and the electrolyte are stored, wherein a material for the battery case is iron, stainless steel, or aluminum, and wherein a wall thickness of the battery case is not less than 0.2 mm and not more than 1 mm, the battery being at least 30 Wh in energy capacity and at least 180 Wh/l in volume energy density, formed by a single cell covered by the battery case, and having a flat shape with a thickness of less than 10 mm and not less than 2 mm, such that heat produced in the battery is releasable via the front and back flat faces of the battery, wherein the battery case houses only one cell, wherein a positive terminal to which said at least one positive electrode is connected and a negative terminal to which said at least one negative electrode is connected are mounted on a flat face of the battery case while being insulated from the battery case.