The invention relates to a
lithium ion battery self-
discharge consistency
screening method. The method comprises the following steps: S1, fully charging n formed battery cells, carrying out constant-current
discharge to 2.5 V after shelving, obtaining a
discharge curve, and recording inflection point
voltage U1 on the curve; s2, recording a corresponding
voltage value on the curve, which is less than or equal to U1 and greater than 3% SOC, as U2; charging the
battery cell to U2; s3, placing all the battery cells T1, placing the battery cells T2 at a high temperature, continuously placing the battery cells T3 at a normal temperature, and testing an open-circuit
voltage OCV2; placing the
battery cell at normal temperature for T4, and testing open-circuit voltage OCV3; s4, calculating a K value of each
battery cell; s5, calculating an average value alpha and a standard deviation sigma of the K values of all the battery cells; and S6, comparing the K value of each battery
cell with the value of alpha + x sigma, and screening out the battery cells of which Ki is greater than alpha + x sigma in the group. According to the method, the test time is shortened, the influence of temperature and polarization on the test is reduced, and the
screening result is more accurate.