METHOD FOR GROUPING LITHIUM SECONDARY BATTERY PACKS

摘要

A method for grouping lithium secondary battery packs, belonging to the field of secondary batteries. (1) charging and discharging a battery for 1 - 3 cycles, recording the last discharge capacity C0, setting a capacity lower limit, and choosing the battery with the C0 thereof being not less than the capacity lower limit as an eligible battery; (2) continuing to discharge with 0.01 C5 - 0.5 C5 to the discharge cut-off voltage of Vd 2.0 V - 3.0 V to discharge the battery to a power empty state; (3) filling the battery in the power empty state that was discharged in step (2) to a capacity C1; (4) storing the battery for time t1 in an environment of 20 - 50°C, measuring and recording the stored battery voltage V1, and then continuing to store the battery for time t2 in the environment of 20 - 50°C, measuring the stored battery voltage V2 and calculating the voltage difference ?V = V2 - V1 and setting the range of ?V; and (5) taking out batteries and grouping the same according to a certain capacity grouping standard. The advantages of the battery pack grouping method in the present invention are that each individual battery in the battery pack has low hidden danger of self-electricity consumption and good discharge consistency and the battery pack is safely assembled with high reliability.