Alkaline dry battery with a nickel oxyhydroxide and manganese oxide positive electrode including a calcium compound
View Patent ↗Provided is an alkaline dry battery allowing suppression of polarization in pulse discharge under heavy load to improve discharge characteristics, and having high reliability in safety in case of short circuit. In the positive electrode, a calcium compound having a content of iron element of 150 ppm or less is added in an amount of 0.1 to 10 mol % with respect to a positive electrode active material, a nickel oxyhydroxide powder having 2.95 or more of an average nickel valence and 8 to 18 μm of an average particle diameter is used, the weight ratio of the nickel oxyhydroxide powder and a manganese dioxide powder is in the range of 20:80 to 90:10. A zinc or zinc alloy powder used as negative electrode active material includes a first powder having a particle diameter more than 75 μm and 425 μm or less, and a second powder having a particle diameter more than 5 μm and 75 μm or less, and the weight ratio of the first powder and the second powder is in the range of 65:35 to 75:25, and the concentration of a potassium hydroxide solution is 33 to 35% by weight.
1. An alkaline dry battery comprising:
a positive electrode including a positive electrode active material comprising a nickel oxyhydroxide powder and a manganese dioxide powder, a conductive agent comprising graphite, and a calcium compound; and
a negative electrode including a negative electrode active material comprising a zinc or zinc alloy powder, a gelling agent, and an aqueous solution of potassium hydroxide, wherein
the positive electrode includes a calcium compound having a content of iron element of 150 ppm or less in an amount of 0.1 to 10 mol % with respect to the positive electrode active material,
the nickel oxyhydroxide powder has an average nickel valence of 2.95 or more and an average particle diameter of 8 to 18 μm,
the weight ratio of the nickel oxyhydroxide powder and the manganese dioxide powder is 20:80 to 90:10,
the zinc or zinc alloy powder includes a first powder having a particle diameter more than 75 μm and 425 μm or less, and a second powder having a particle diameter more than 5 μm and 75 μm or less, the weight ratio of the first powder and the second powder is 65:35 to 75:25, and
the concentration of the aqueous solution of potassium hydroxide is 33 to 35% by weight.
2. The alkaline dry battery according to claim 1 , wherein the nickel oxyhydroxide powder is obtained by oxidizing a nickel hydroxide powder having a half width of the (101) face of 0.6 to 0.8 deg./2θ, and a half width of the (001) face of 0.5 to 0.7 deg./2θ in a powder X-ray diffraction.
3. The alkaline dry battery according to claim 1 , wherein the calcium compound is a calcium oxide or calcium hydroxide.