Patent attributes
A flat alkaline primary battery is provided. The annular end portion of the negative electrode can is engaged with the annular end portion of the positive electrode can so that the positive electrode can and the negative electrode can are connected via a gasket to create an enclosed space inside the cans. The enclosed space accommodates a separator, a positive electrode mixture having a positive electrode active material as a main component, and a negative electrode mixture having a negative electrode active material as a main component. The enclosed space is filled with an alkaline electrolyte. The positive electrode active material is oxy nickel hydroxide. The negative electrode active material is a zinc or zinc alloy powder. The mass of the oxy nickel hydroxide is between 3.9 and 4.4, times, inclusive, of the mass of the zinc or the zinc alloy. Alternatively, the mass of the oxy nickel hydroxide is between 3.3 times, inclusive, the mass of the zinc or the zinc alloy.