Res. Chem. Intermed.
, Vol. 32, No. 5–6, pp. 461–471 (2006)
Also available online - www.vsppub.com
Improvement of basic performances of a nickel–metal
and MUNEHISA IKOMA
Matsushita Battery Industrial Co., Ltd., 1-1 Matsushita-cho, Moriguchi, Osaka 570-8511, Japan
Received 22 November 2004; accepted 28 December 2004
Abstract—To develop a sealed-type nickel–metal hydride battery for use in portable equipment or
in electric vehicles, investigations were conducted on negative electrodes using AB
storage alloy and positive electrodes. For the cycle life performance of the battery, alkaline treatment
of the alloy and the substitution of more than 50% to the alloy with Co were effective. For the positive
electrode, zinc as a solid solution in the nickel positive electrode obviously prevented γ -NiOOH from
being formed in the charging process of β-Ni(OH)
and suppressed the migration of the electrolyte
solution in the separator to the active material of the positive electrode. Also, hydrophobic treatment
of the surface of the alloy was effective to prevent the elevation of the battery internal pressure of the
battery in high rate charge.
Keywords: Nickel–metal hydride battery; AB
-type hydrogen storage alloy; performance.
Recently, nickel–metal hydride (Ni-MH) batteries, using hydrogen storage alloy for
the negative electrode, have come to be widely used in various portable electronic
devices because of their high capacity and long cycle life. In the Ni-MH battery,
hydrogen storage alloy, which contains no poison and is environment-friendly
compared with a conventional Ni-Cd battery, is utilized as the negative electrode.
However, many problems must be overcome for the commercialization of the Ni-
MH battery, in particular, improvement of the cycle life performance and the rapid
charge performance is important. In this study, attempts were made to solve the
problems of various performances by studying the negative electrodes of AB
hydrogen storage alloys and the positive electrode in order to develop a sealed-type
Ni-MH battery suitable for use in the portable devices and electric vehicles.
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