Battery protection mechanism

A system for preventing battery damage by internal battery abnormalities during charging or discharging states of the battery, comprising:

• a first circuit for automatically determining when the battery is in a charging state and when the battery is in a discharging state;
• a second circuit for sampling a voltage of the battery at sequential time points;
• a third circuit for measuring a decline of the voltage;
• a fourth circuit for counting Tdec, which is a time during which the voltage is in decline, and for counting Trise, which is a time during which the voltage increases after a period of decline, wherein the count of Tdec is reset to zero when Trise lasts longer than a preset time delay, and wherein the count of Tdec is resumed when the voltage resumes its decline after a period of increase and Trise of the period of increase is shorter than the preset time delay;
• a fifth circuit for measuring a rate of the decrease of the voltage;
• and
• a sixth circuit for producing an indicator of internal battery abnormality under the following conditions:
• when the battery is in the discharging state and the rate of the decrease of the voltage exceeds a predetermined decline rate;
• when the battery is in the charging state and Tdec exceeds a predetermined time;
• and
• when the battery is in the charging state and the decrease of the voltage exceeds a predetermined voltage.