Method of restoring secondary battery and method of reusing secondary battery
A secondary battery restoring method includes a first step of determining whether or not a value of an input-output characteristic of a secondary battery or a battery module is within a predetermined range of reference values, and a second step of adjusting the secondary battery or the battery module to a predetermined low SOC condition of from 0% to 20% SOC and thereafter leaving the secondary battery or the battery module to stand if, in the first step, the value of the input-output characteristic is determined to be outside the predetermined range of reference values.
1. A secondary battery restoring method comprising:
a first step of determining an I-V resistance value of a secondary battery or a battery module is within a predetermined range of reference I-V resistance values;
the first step comprising adjusting the secondary battery or the battery module to 45% to 70% SOC, then discharging the secondary battery or the battery module at a predetermined constant current value for a predetermined time, and then measuring the I-V resistance value of the secondary battery or the battery module and determining if it is within the predetermined range of the reference I-V resistance values;
a second step of adjusting the secondary battery or the battery module to a predetermined low SOC condition of from 0% to 20% SOC and thereafter leaving the secondary battery or the battery module to stand if, in the first step, the I-V resistance value was determined to be outside the predetermined range of reference I-V resistance values; and
a third step of determining, subsequent to the second step, whether the I-V resistance value of the secondary battery or the battery module is within the predetermined range of reference I-V resistance values;
the third step comprising adjusting the secondary battery or the battery module to 45% to 70% SOC, then discharging the secondary battery or the battery module at a second predetermined constant current value for a second predetermined time, and then measuring the I-V resistance value of the secondary battery or the battery module and determining if it is within the predetermined range of the reference I-V resistance values.
2. A secondary battery reusing method comprising:
a first step of determining an I-V resistance value of a secondary battery or a battery module is within a predetermined range of reference I-V resistance values;
the first step comprising adjusting the secondary battery or the battery module to 45% to 70% SOC, then discharging the secondary battery or the battery module at a predetermined constant current value for a predetermined time, and then measuring the I-V resistance value of the secondary battery or the battery module and determining if it is within the predetermined range of the reference I-V resistance values;
a second step of adjusting the secondary battery or the battery module to a predetermined low SOC condition of from 0% to 20% SOC and thereafter leaving the secondary battery or the battery module to stand for a predetermined time period if, in the first step, the I-V resistance value was determined to be outside the predetermined range of reference I-V resistance values;
a third step of determining, subsequent to the second step, whether the I-V resistance value of the secondary battery or the battery module is within the predetermined range of reference I-V resistance values;
the third step comprising adjusting the secondary battery or the battery module to 45% to 70% SOC, then discharging the secondary battery or the battery module at a second predetermined constant current value for a second predetermined time, and then measuring the I-V resistance value of the secondary battery or the battery module and determining if it is within the predetermined range of the reference I-V resistance values;
a fourth step of determining the secondary battery or the battery module to be unusable if, in the third step, the I-V resistance value was determined to be outside the predetermined range of reference I-V resistance values; and
a fifth step of determining that the secondary battery or the battery module is usable if, in the first step or in the third step, the I-V resistance value was determined to be within the predetermined range of reference I-V resistance values.
3. The secondary battery reusing method according to claim 2 , further comprising a sixth step of adjusting the secondary battery or the battery module to a predetermined SOC if, in the third step, the I-V resistance value was determined to be within the predetermined range of reference I-V resistance values.