This paper reports the preparation of a nickel-metal hydride (Ni-MH) rechargeable battery with a high capacity of 96V-14Ah and a high energy density of 1.4kWh. The negative electrode was prepared with a rare earth based MmNi(5) type hydrogen storage alloy and graphite as a conductive material. The prepared Ni-MH battery was installed into a solar vehicle. The data obtained from a three-day long world solar car rally yielded high discharge-to-charge coulomb efficiency (76%) and solar-to-electric energy conversion efficiency (60%) in average, in spite of severe rally conditions.