Battery charging/discharging control device and method for controlling same

A battery charge and discharge control device, comprising:

• a voltage sensor for measuring the voltage of a battery;
• and
• a control unit, which controls charge and discharge of the battery to ensure that the measured voltage of the battery is within a use range of the voltage corresponding to a use time period of the battery,
• wherein:
• the control unit controls the charge and discharge of the battery by setting the use range of the voltage to be within the use range of a first voltage during an initial-use time period, and setting the use range of the voltage to be within the use range of a second voltage during an intermediate-use time period;
• the use range of the voltage corresponds to a voltage difference between an end-of-charge voltage and an end-of-discharge voltage;
• the use range of the second voltage is greater than the use range of the first voltage;
• the control unit sequentially increases the end-of-charge voltage and sequentially reduces the end-of-discharge voltage during the intermediate-use time period;
• a first full-charge voltage of the battery is FCV, a negative electrode threshold potential is NECV, a deterioration condition is AC, a capacity reduction rate is CRR, a reference end-of-charge voltage is REOC, a first reference end-of-discharge voltage is REOD1, and a second end-of-discharge voltage is REOD2,
• the end-of-charge voltage (EOC) is determined according to the equation
• EOC=REOC+(FCV−NECV−REOC)*CRR/(100−AC);
• the end-of-discharge voltage (EOD) is determined according to the equation
• EOD=REOD1−(REOD1−REOD2)*CRR/(100−AC);
• the negative electrode threshold potential is a potential value of a negative electrode where a negative electrode active material contained in the battery causes a phase change;
• the deterioration condition is a percentage value corresponding to a threshold discharge capacity that is reduced relative to an initial discharge capacity of the battery;
• the capacity reduction rate is a percentage value corresponding to a difference between the initial discharge capacity and a present discharge capacity of the battery;
• the reference end-of-charge voltage and the first reference end-of-discharge voltage correspond to the use range of the first voltage;
• and
• a second reference end-of-discharge voltage is lower than the first reference end-of-discharge voltage.

A method for controlling charge and discharge of a battery, comprising:

• charging and discharging a battery by having a voltage range of the battery used as a use range of a first voltage, during an initial-use time period;
• charging and discharging the battery by having the voltage range of the battery used as a use range of a second voltage, during an intermediate-use time period;
• and
• charging and discharging the battery by having the voltage range of the battery used as a use range of a third voltage, during a late-use time period,
• wherein the voltage range used corresponds to a voltage difference between an end-of-charge voltage and an end-of-discharge voltage, and
• wherein the use range of the second voltage is greater than the use range of the first voltage, and greater than the use range of the third voltage.