Internal short detection apparatus for secondary-battery, internal short detection method for secondary-battery, battery-pack, and electronic equipment

A secondary-battery internal short detection method for detecting an internal short in a secondary-battery, comprising:

• an electricity-quantity accumulating step of measuring an accumulative electricity-quantity necessary for charging the secondary-battery from a first voltage to a second voltage higher than the first voltage;
• an electricity-quantity comparing step of comparing the accumulative electricity-quantity measured in the electricity-quantity accumulating step and a reference electricity-quantity which is stored in advance in an electricity-quantity storage circuit and is necessary for charging the secondary-battery from the first voltage to the second voltage;
• an internal short detecting step of deciding that an internal short is generated, if the accumulative electricity-quantity is larger than the reference electricity-quantity in the electricity-quantity comparing step;
• and
• a reference electricity-quantity rewriting step of deciding that an internal short is not generated and rewriting the reference electricity-quantity stored in the electricity-quantity storage circuit into the accumulative electricity-quantity, if the accumulative electricity-quantity is equal to, or smaller than, the reference electricity-quantity in the electricity-quantity comparing step.