Alloy powder for electrodes, negative electrode for nickel-metal hydride storage batteries including the same, and nickel-metal hydride storage battery including the same

摘要

Disclosed is an alloy powder for electrodes for nickel-metal hydride storage batteries having a high battery capacity and being excellent in life characteristics and high-temperature storage characteristics. The alloy powder includes a hydrogen storage alloy containing elements L, M, Ni, Co, and E. L includes La as an essential component. L includes no Nd, or when including Nd, the percentage of Nd in L is less than 5 mass %. The percentage of La in the hydrogen storage alloy is 23 mass % or less. M is Mg, Ca, Sr and/or Ba. A molar ratio α to a total of L and M is 0.045≤α≤0.133. A molar ratio x of Ni to the total of L and M is 3.5≤x≤4.32, and a molar ratio y of Co is 0.13≤y≤0.5. The molar ratios x and y, and a molar ratio z of E to the total of L and M satisfy 4.78≤x+y+z5.03.