Method for sorting lithium cells

A method for sorting lithium cells, comprising:

• quick sorting and high-precision sorting,
• wherein the quick sorting comprises the following steps:
• step 1:
• equalizing factory-fresh cells;
• step 2:
• randomly selecting a certain number of cells, connecting the plurality of cells into a single-ammeter parallel circuit in parallel, monitoring a current change of an ammeter, judging, according to monitoring data, whether there are cells with large self-discharge, if no, sorting the cells into groups, and if yes, proceeding to step 3;
• and
• step 3:
• connecting an ammeter to each branch of the circuit of parallel connection of the plurality of cells, finding out cells with greater self-discharge rates than other cells according to an established equivalent circuit model with self-discharge, and sorting the remaining cells into groups;
• wherein the high-precision sorting comprises the following steps:
• step a:
• equalizing the factory-fresh cells;
• and
• step b:
• randomly selecting a certain number of cells, connecting the batch of cells in parallel, connecting the ammeter to each branch, observing a current change in each branch, eliminating a cell with a large relative self-discharge rate according to an established equivalent circuit model with self-discharge, and sorting the remaining cells with similar self-discharge rates into groups;
• and
• wherein in step b, the function of connecting an ammeter to each branch is to sort cells with similar relative self-discharge rates into groups:
• a cell with a known self-discharge rate is connected in a high-precision sorting scheme, a current change quantity of a branch where the cell with the known self-discharge rate is located is compared with the current change quantity collected by the ammeter in real time within the specified time, and cells with self-discharge rates of 1%, 2%, 3%, 4%, and 5% are distinguished and sorted into groups respectively.