The invention discloses a
lithium secondary battery consistency
screening method, belonging to the field of secondary batteries, characterized in that: a unit battery grades the capacity, platform, and
internal resistance when conducting capacity grading and detection, and then the unit battery is charged by multi-step
constant current and
constant voltage, wherein a
constant current of 0.3-5C5 is used for charging to a
voltage V0, when the charging current is 0.1-0.3 C5, the charge is stopped and the battery is shelved; after the battery is shelved for 5-30 min, the charging is continued with a
constant current of 0.1-0.3 C5 to the
voltage V0, when the charging current is 0.05-0.1 C5, the charge is stopped and the battery is shelved; after the battery is shelved for 5-30 min, the charging is continued with a constant current of 0.05-0.1 C5 to the
voltage V0, when the charging current is 0.03-0.05 C5, the charge is stopped and the battery is shelved; after the battery is shelved for 5-30 min, the charging is continued with a constant current of 0.03-0.05 C5 to the voltage V0, when the charging current is 0.01-0.03 C5, the charge is stopped; after the charging is complete, the unit battery is shelved at a normal temperature, the shelving time is no less than 24h, when the shelving ends, measurement is carried out on the open-circuit voltage Vt of the unit battery, if the open-circuit voltage Vt is no less than the result of V0 minus
delta V0 and minus n*
delta V, the unit battery is qualified. According to the invention, the qualified unit battery screened by the invention has low self-consuming hazards, the combined
battery pack has good self-
discharge consistency, high reliability, and rapidness, simpleness and easy operation in practical application, and has a good market application prospect.