Patent ID: 7560901

Claim:
A secondary-battery internal short detection apparatus which detects an internal short in a secondary-battery, comprising: an electricity-quantity storage circuit which stores a reference electricity-quantity necessary for charging the secondary-battery from a first voltage to a second voltage higher than the first voltage; an electricity-quantity accumulation circuit which 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 which 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 decides that an internal short is not generated and rewrites the reference electricity-quantity stored in the electricity-quantity storage circuit into the accumulative electricity-quantity.