SEALED BATTERY

PROBLEM TO BE SOLVED: To provide a sealed battery with high volume capacity density using a metal case, prevented from short-circuit between a battery element and a battery case caused by the melting of a separator due to the heat generated when welding a tub for electric connection to the bottom surface of the battery case. SOLUTION: The battery case 2 of the sealed battery 1 has a plurality of protrusions 4 protruding toward the inside of the battery case on the bottom surface 3. By the above, as a battery element bottom surface 7, covered by an insulation tape 6 covering the lower part of the battery element 5 inserted in the battery case 2, is partially held by the protrusions, a space 8 is formed between a battery case bottom surface 3 and the battery element bottom surface 7, and the thermal effect at welding is reduced. The protrusions 4 can be formed by pressing the outer surface of the battery case 2 after forming the same. It is necessary to form at least two protrusions, and is it recommendable to form the protrusions at the position capable of uniformly holding the battery. It is recommendable to form the protrusions with a height of 0.1 mm-0.2 mm, and with the diameter of 0.5 mm-1.0 mm. COPYRIGHT: (C)2003,JPO