Worn-out power battery secondary use screening method

Abstract

The invention relates to a worn-out power battery secondary use screening method. The whole of a battery pack is charged and discharged, through data recorded by the BMS in a test, in the discharging process, 2 to 4 SOC points with the SOC value ranging from 20% to 90% are selected, and voltage of each monomer in series is read; the batteries which are deviated from most of the batteries and overpass 5% in the voltage value are determined to be batteries of problems, and the residual batteries are initially identified as batteries in healthy states; internal resistance of each battery in the residual batteries is measured, a second screening is conducted through the inner resistance value, battery cells which deviate from normal resistance of the most battery cells by 20% are eliminated and the screening is finished; 10 batteries are randomly selected from the residual batteries to be charged and discharged, the average capacity of the 10 batteries is deemed as the capacity value of all the batteries in the healthy states. Compared with the detection method of the prior art, times of charging and discharging are greatly reduced, time needed by the new screening method is about 1 / 10 less than the traditional method, quantity demand for charging and discharging devices is greatly reduced, and equipment investment is reduced.

Description

technical field [0001] The invention relates to a screening method for secondary use of waste power batteries, in particular to a screening method for power lithium iron phosphate (LFP) lithium-ion batteries discarded after electric vehicles are used, and belongs to the technical field of power lithium-ion batteries. Background technique [0002] Energy and the environment have become the most concerned issues in the world. As a major consumer of oil resources and polluting the environment, traditional fuel vehicles are constantly being impacted by new clean energy vehicles. Electric vehicles replace oil with electricity and can achieve "zero emission" and "low noise", which is an important means to solve energy and environmental problems. With the shortage of petroleum resources and the development of battery technology, electric vehicles have gradually been popularized and applied all over the world. It has become a general consensus that the new generation of energy-sav...

AI Technical Summary

Problems solved by technology

A power battery pack contains at least more than 100 single cells, and at most hundreds of cells. Such a screening method is time-consuming and labor-intensive.

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