Evaluation of Zr(Ni,Mn)2 Laves phase alloys as negative active material for Ni-MH electric vehicle batteries

Laves phase alloys of compositions (Zr, Ti)(Ni, Mn, M)(x) where M = Cr, V, Co, Al, and 1.9 < x < 2.1 with hexagonal C14 or cubic C15 structure have been studies in order to select the most suitable AB(2) alloys as an active material for nickel-metal hydride (Ni-MH) batteries. With the selected alloy, feasibility of MH negative electrodes using industrial technology and containing more than 97% of the alloy powder has been demonstrated. 22 Ah Ni-MH batteries for electric vehicle application have been assembled, and 600 cycles have been achieved at steady C/3 charge and discharge rates and 80% depth of discharge.