The invention discloses a self-
discharge screening method for improving the matching consistency of
lithium ion batteries. The self-
discharge screening method for improving the matching consistency ofthe
lithium ion batteries comprises the following steps that after the same batch of batteries are subjected to conventional capacity grading, 5-20% SOC state-of-charge electric quantity is charged in a 4-6A
current constant current charging mode. After the batteries are put on hold at normal temperature for 24-48h, the
battery voltage is measured as OCV1, then the temperature is turned to 45 DEGC, and the batteries are put on hold for 120-168h, then the
battery voltage is measured as OCV 2, then the batteries are put on hold at normal temperature, the
battery voltage is measured as OCV3 again, values of OCV1, OCV2 and OCV3 are measured, and the
voltage difference is calculated, that is ,
delta V1= OCV1-OCV2 and
delta V2= OCV2-OCV3; and an out-of-tolerance
value code of the
delta V1 is VO1, an out-of-tolerance
value code of the
delta V2 is VO2, a batch of out-of-tolerance batteries can be roughly eliminated with a VO1 set value, and then a batch of the batteries can be finely eliminated with a VO2 set value. The self-
discharge screening method for improving the matching consistency of the
lithium ion batteries has simple and convenient implementation, high matching precision, good consistency and high matching efficiency, and is especially suitable for
batch production application.