Method and apparatus for determining battery life

A computer apparatus having a battery pack which repeatedly charges and discharges to supply power from the battery pack to a system body,

• wherein the battery pack comprises:
• a voltage measurement circuit for measuring a battery voltage;
• a current measurement circuit for measuring a charge current;
• and
• a CPU for computing an internal impedance in accordance with the measured battery voltage and charge current, and
• wherein the system body comprises:
• a controller for determining a life of the battery pack in accordance with the internal impedance computed by the CPU of the battery pack;
• and
• a display for displaying a message about the determined life.

A battery-life determination system for determining the life of a secondary battery for supplying power to a body, the system comprising:

• an under-charge-battery-voltage measurement unit for measuring the battery voltage while the secondary battery is charged;
• a charge current measurement unit for measuring the charge current while the secondary battery is charged;
• a stop unit for stopping charge of the secondary battery while the secondary battery is charged;
• an under-stop-battery-voltage measurement unit for measuring the under-stop battery voltage of the secondary battery while charge of the secondary battery is stopped by the stop unit;
• an internal impedance computation unit for computing the internal impedance of the secondary battery in accordance with the battery voltage and charge current under the charge and the under-stop battery voltage;
• and
• a life determination unit for determining the life of a battery in accordance with the internal impedance computed by the internal impedance computation unit.

A battery for supplying power to a body by repeating charge and discharge, comprising:

• an under-charge-voltage measurement unit for measuring the battery voltage under charge;
• a current measurement unit for measuring the charge-current value under charge;
• an under-stop-voltage measurement unit for measuring the battery voltage when charge is stopped;
• and
• a computation unit for computing an internal impedance in accordance with the battery voltage measured by the under-charge-voltage measurement unit, the charge current value measured by the current measurement unit, and the battery voltage measured by the under-stop-voltage measurement unit.

A battery-life detection method for detecting a life of a battery for supplying power to a body by performing charge and discharge, comprising the steps of:

• measuring a battery voltage while the battery is charged;
• measuring a charge current value while the battery is charged;
• measuring a charge-stop battery voltage when charge of the battery is stopped;
• computing an internal impedance of a battery in accordance with the battery voltage, the charge current value, and the charge-stop battery voltage;
• and determining the life of the battery in accordance with the internal impedance.

A battery-life detection method for detecting a life of a battery for performing charge and discharge and supplying power to a body, comprising the steps of:

• measuring the voltage of the battery at a constant current whose value is stabilized while the battery is charged or discharged;
• measuring the current value of the battery at the constant current;
• stopping supply of current at the constant current;
• measuring the stop battery voltage that is the voltage of the battery when supply of the current is stopped;
• computing the internal impedance of a battery in accordance with the battery voltage, the current value, and the stop battery voltage;
• and
• determining the life of a battery in accordance with the internal impedance.