Apparatus for managing safety of secondary battery and method thereof

An apparatus for managing safety of a secondary battery including a plurality of cells, the apparatus comprising:

• a voltage measuring unit configured to measure voltages of the plurality of cells;
• a temperature measuring unit configured to measure temperatures of the plurality of cells;
• a discharging switch connected in parallel with a charging and discharging path of the secondary battery;
• a load resistor connected between the discharging switch and a ground;
• and
• a control unit operably coupled to the voltage measuring unit, the temperature measuring unit and the discharging switch,
• wherein the control unit is configured to:
• measure voltages and temperatures of the plurality of cells through the voltage measuring unit and the temperature measuring unit,
• turn on the discharging switch to forcibly discharge the secondary battery through the load resistor when it is determined that a state where a maximum value of the cell voltages and a maximum value of the cell temperatures are respectively equal to or greater than a critical voltage and a critical temperature according to a preset swelling management condition continues over a reference time, and
• turn off the discharging switch when the maximum value of a plurality of cell voltages and the maximum value of a plurality of cell temperatures respectively measured through the voltage measuring unit and the temperature measuring unit during the forced discharge falls below a preset safe voltage or a preset safe temperature, respectively according to the swelling management condition,
• wherein the swelling management condition is set as a plurality of conditions, and the critical voltage, the critical temperature and the reference time are set independently for each condition among the plurality of conditions,
• wherein the critical voltage, the critical temperature and the reference time are determined based on a set swelling level of the secondary battery, and
• wherein the reference time is set based on a time duration for a volume of a cell of the plurality of cells to increase a set percent and subtracting a margin of safety from the time duration.

A method for managing safety of a secondary battery, the method comprising:

• providing a discharging switch connected in parallel with a charging and discharging path of the secondary battery and a load resistor connected between the discharging switch and a ground;
• measuring voltage and temperature of a cell included in the secondary battery by using a voltage measuring unit and a temperature measuring unit;
• turning on the discharging switch to forcibly discharge the secondary battery through the load resistor when a state where the cell voltage and the cell temperature are respectively equal to or greater than a critical voltage and a critical temperature according to a preset swelling management condition continuing over a reference time;
• and
• turning off the discharging switch when the cell voltage or the cell temperature measured through the voltage measuring unit or the temperature measuring unit during the forced discharge falls below a preset safe voltage or a preset safe temperature according to the swelling management condition,
• wherein the swelling management condition is set as a plurality of conditions, and the critical voltage, the critical temperature and the reference time are set independently for each condition among the plurality of conditions,
• wherein the critical voltage, the critical temperature and the reference time are determined based on a set swelling level of the secondary battery, and
• wherein the reference time is set based on a time duration for a volume of the cell to increase a set percent and subtracting a margin of safety from the time duration.

A method for managing safety of a secondary battery, the method comprising:

• providing a discharging switch connected in parallel with a charging and discharging path of the secondary battery including a plurality of cells and a load resistor connected between the discharging switch and a ground;
• measuring voltages and temperatures of the plurality of cells through a voltage measuring unit and a temperature measuring unit;
• turning on the discharging switch to forcibly discharge the secondary battery through the load resistor when it is determined that a state where a maximum value of the cell voltages and a maximum value of the cell temperatures are respectively equal to or greater than a critical voltage and a critical temperature according to a preset swelling management condition continuing over a reference time;
• and
• turning off the discharging switch when a maximum value of the cell voltages and a maximum value of the cell temperatures measured through the voltage measuring unit and the temperature measuring unit during the forced discharge falls below a preset safe voltage or a preset safe temperature according to the swelling management condition,
• wherein the swelling management condition is set as a plurality of conditions, and the critical voltage, the critical temperature and the reference time are set independently for each condition among the plurality of conditions,
• wherein the critical voltage, the critical temperature and the reference time are determined based on a set swelling level of the secondary battery, and
• wherein the reference time is set based on a time duration for a volume of a cell of the plurality of cells to increase a set percent and subtracting a margin of safety from the time duration.