SEALED DRY CELL

PURPOSE:To suppress gas generation in a sealed dry cell, and suppress the capacity change and the dimensional change of the dry cell which are caused with the passing of time by using as a negative electrode, a mixture prepared by combining an amalgamated zinc powder with both a water-soluble macromolecular powder and ZnO. CONSTITUTION:A negative active material 2-a is prepared by mixing an amalgamated zinc powder with small amounts of at least one compound chosen from among sodium polyacrylate, carboxymethylcellulose and etherified starch, and adding ZnO to the mixture before thus obtained mixture is homogeneously mixed. Then, an amount corresponding to 60mAH theoretical capacity of the negative active material 2-a is packed into a sealed dry cell. A positive active material 4 is prepared by mixing 90 parts by weight of gamma-MnO2 powder with 10 parts by weight of acetylene black, combining 90 parts by weight of the mixture with 10 parts by weight of electrolyte prepared by saturating an aqueous solution containing 25% of ZnCl2 and 5% of NH4Cl with ZnO, and stirring and granulating thus obtained mixture before it is molded. After thus prepared positive pellet 4 and a positive seat 7 are pressed upon a positive can 5 so as to unify them with the positive can 5, a separator 3 is placed over the positive pellet 4, and the above mentioned negative active material 2-a is packed on the separator 3. Next, a negative can 1 to which a gasket 6 is attached is fitted inside the positive can 5 by pressure, and the opening end of the positive can 5 is inwardly caulked so as to seal the dry cell, thereby completing the assembly of a sealed dry cell.