Lithium ion battery sorting method

Abstract

The invention discloses a lithium ion battery sorting method. The lithium ion battery sorting method comprises following steps: a plurality of lithium ion batteries are fully charged respectively; charge maintenance is carried out; each lithium ion battery is subjected to constant-current discharge at a first discharging current rate until the voltage is as large as a discharge cut-off voltage, and a first discharge capacity is recorded; each lithium ion battery is subjected to constant-voltage constant-current charge until fully charged; each lithium ion battery is subjected to constant-current discharge at a second discharging current rate until the voltage is as large as an intermediate voltage, and a second discharge capacity is recorded ; each lithium ion battery is subjected to short time pulse current charging and pulse curret discharging; each lithium ion battery is subjected to constant-current discharge at the second discharging current rate until the voltage is as large as an cut-off voltage, and a third discharge capacity is recorded; and the lithium ion batteries are subjected to sorting based on the first discharge capacity, the second discharge capacity, and the third discharge capacity. The lithium ion battery sorting method is capable of increasing sorting and matching efficiency, saving time, reducing cost, and increasing consistency of lithium ion battery matching at the same time, so that battery pack applicability is improved and service life is prolonged.

Description

technical field [0001] The invention belongs to the technical field of batteries, and in particular relates to a lithium ion battery sorting method. Background technique [0002] At present, lithium-ion battery packs basically follow the sorting process of traditional electronic products, that is, in the battery capacity division stage, the battery cells are charged with constant current and constant voltage to the cut-off voltage and cut-off current, and then discharged to the cut-off voltage. The static capacity, the discharge rate is generally 1C or 0.5C. Then the static capacity is used as the main sorting parameter, and the 1KHz AC internal resistance measured by the AC internal resistance instrument is used as the reference parameter, and those with similar capacity and internal resistance are grouped into a group. The traditional lithium-ion battery sorting process has at least the following disadvantages: (1) The static capacity does not match the actual static capa...

AI Technical Summary

Problems solved by technology

The traditional lithium-ion battery sorting process has at least the following disadvantages: (1) The static capacity does not match the actual static capacity of the battery pack, because the constant voltage capability of the battery pack is very weak, and the discharge capacity of the battery cell after constant voltage charging cannot truly reflect the actual capacity of the battery pack. (2) The sub-capacity current is so small that there is no distinction in capacity; (3) The difference in storage capacity between cells is not considered; (4) The AC and AC internal resistance is very unstable, and it is difficult to reflect the battery's superiority. (5) It will consume a lot of manpower, equipment and time costs to arrange the capacity and internal resistance close to each other in sequence, and will aggravate the inconsistency between battery packs

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