The production of small-sized M-MH batteries, which amounts to some 40% of market share for portable appliances, is still growing because of an increase in the energy density per volume and also a reduction in price. Highly efficient electric vehicles (EV) propelled by a large-sized Ni-MH battery have been commercialized and have twice the driving range of a conventional EV with a Pb-acid battery. A hybrid vehicle with a high-powered Ni-MH battery has been brought onto the market, providing twice the gas mileage and half the CO2 emissions of a gasoline vehicle. A fuel cell electric vehicle with hydrogen tank or methanol reformer, power-assisted by a Ni-MH battery, is under development. The Ni-MH battery will be a key component for the next generation of vehicles in addition to advanced information and telecommunication systems. (C) 1999 Elsevier Science S.A. All rights reserved.