SEALED BATTERY AND MANUFACTURE THEREOF

PURPOSE:To prevent danger of internal short-circuit, improve the plate charging efficiency and increase the battery capacity by making the protrusion dimension of a seat inwardly protruded toward the inside of a metal case smaller than the summed dimension of the thickness of the outermost plate of a plate group made in contact with the metal case and the thickness of a separator. CONSTITUTION:A metal case 1 is formed in a bottomed cylinder by deep drawing of a nickel-plated steel plate, and a plate group having a positive plate 2 mainly consisting of nickel oxide and a negative plate 3 mainly consisting of cadmium oxide wound through a separator 4 in such a manner that the negative plate 3 is exposed on the most outer side is inserted into the metal case 1. An inner protruded seat 1c is formed when the opening part of the metal case 1 is throttled to a drum part dimension, and the protrusion dimension of the inner protruded seat 1c toward the inside of the metal case 1 is made smaller than the accumulation of dimensions of the thickness of the most outer side negative plate 3 of the plate group made in contact with the metal case 1 and the thickness of the separator 4. Thus, a dimensional reduction of the plate and the provision of an insulating material are not required. Hence, the danger prevention of internal short circuit, an improvement in charging efficiency of the plate group, and an increase in capacity can be achieved.