BATTERY PACK AND CHARGER SYSTEM

1 . A battery pack comprising:

a plurality of secondary battery cells;

a voltage measurement module configured to measure a voltage of each of the plurality of secondary battery cells;

a charge switching module configured to turn on and off a charge current to the plurality of secondary battery cells;

a first judgment module configured to judge whether a highest voltage value measured by the voltage measurement module is equal to or greater than a predetermined value; and

a charge stop module configured to turn off the charge switching module when the highest value is equal to or greater than a predetermined value.

2 . The battery pack of claim 1 , further comprising:

a monitoring module configured to monitor the voltage of each of the plurality of secondary battery cells;

a stop module configured to stop monitoring the voltage value measured by the voltage measurement module at the same time as when the switching module is turned off;

a second judgment module configured to judge whether a predetermined period of time has elapsed after the charge switching module is turned off; and

a start module configured to start monitoring the voltage value measured by the voltage measurement module after the predetermined period of time has elapsed.

3 . The battery pack of claim 1 , further comprising:

a current detector configured to detect a discharge current output from the plurality of secondary battery cells; and

a switch-on module configured to turn on the charge switching module when a discharge current is detected by the current detector.

4 . The battery pack of claim 1 , further comprising:

a discharge switching module configured to turn on and off a discharge current from the plurality of secondary battery cells;

a third judgment module configured to judge whether the lowest voltage value measured by the voltage measurement module is equal to or lower than a predetermined value; and

a discharge stop module configured to turn off the discharge switching module when the lowest value is equal to or lower than a predetermined value.

5 . The battery pack of claim 4 , further comprising:

a monitoring module configured to monitor the voltage of each of the plurality of secondary battery cells;

a stop module configured to stop monitoring the voltage value measured by the voltage measurement module at the same time as when the discharge switching module is turned off;

a fourth judgment module configured to judge whether a predetermined period of time has elapsed after the discharge switching module is turned off; and

a start module configured to start monitoring the voltage value measured by the voltage measurement module after the predetermined period of time has elapsed.

6 . The battery pack of claim 4 , further comprising:

a current detector configured to detect a charge current value to the plurality of secondary battery cells; and

a switch-on module configured to turn on the discharge switching module when the charge current value is detected.

7 . A charging system comprising:

the battery pack of claim 1 ;

a power source;

a switching module configured to turn on and off supply of a charge current to the plurality of secondary battery cells from the power source;

a current detector configured to detect the charge current supplied to the plurality of secondary batteries; and

a switch-off module configured to turn off the switching module when the charge current has been detected as being interrupted by the charge detector.

8 . The charging system of claim 7 , further comprising:

a voltage detector configured to detect a voltage of the secondary battery cells;

a fifth judgment module configured to judge whether the voltage detected by the voltage detector has become equal to or lower than a predetermined value after the switching module is turned off; and

a switch-on module configured to turn on the switching module.

9 . The charging system of claim 7 , further comprising:

a sixth judgment module configured to judge whether a predetermined period of time has elapsed after the switching module has been turned off, and

a switch-on module configured to turn on the switching module after the predetermined period of time has elapsed.

10 . A charging system comprising:

the battery pack of claim 2 ;

a power source;

a switching module configured to turn on and off supply of a charge current to the plurality of secondary battery cells from the power source;

a current detector configured to detect a charge current supplied to the plurality of secondary batteries;

a voltage detector configured to detect an overall voltage of the plurality of secondary battery cells;

a module configured to turn off the switching module and stop monitoring a voltage detected by the voltage detector when the current detector has detected that the charge current has been interrupted;

a module configured to judge whether a period of time longer than the predetermined period of time has elapsed;

a module configured to judge whether the voltage detected by the voltage detector has become equal to or lower than a predetermined voltage after the period of time longer than the predetermined period of time has elapsed; and

a module configured to resume charging when the voltage detected by the voltage detector has become equal to or lower than a predetermined voltage.