A secondary-battery internal short detection apparatus is provided which
is capable of precisely detecting an internal short being generated in a
secondary-battery. In this apparatus: an electricity-quantity storage
circuit stores in advance a reference electricity-quantity necessary for
charging the secondary-battery from a first voltage to a second voltage;
an electricity-quantity accumulation circuit measures an accumulative
electricity-quantity necessary for charging the secondary-battery from
the first voltage to the second voltage; and an internal short detection
circuit compares the accumulative electricity-quantity measured by the
electricity-quantity accumulation circuit and the reference
electricity-quantity stored in the electricity-quantity storage circuit,
if the accumulative electricity-quantity is larger than the reference
electricity-quantity, then decides that an internal short is generated,
and if the accumulative electricity-quantity is equal to, or smaller
than, the reference electricity-quantity, then without deciding that an
internal short is generated, rewrites the reference electricity-quantity
stored in the electricity-quantity storage circuit into the accumulative
electricity-quantity.