Method used for rapid sorting of lithium ion batteries

Abstract

The invention discloses a method used for rapid sorting of lithium ion batteries. The method comprises following steps: (1) three times of charge-discharge cycles are performed under a charge and discharge rate of 0.05 to 1.5C; (2) discharge capacity, total charge capacity, constant current charge capacity and constant current ratio of the third charge-discharge cycle are recorded; (3) the lithium ion batteries are allowed to stand for 12 to 72h; (4) open-circuit voltage and internal resistance are determined; (5) lithium ion batteries with a discharge capacity less than 1.05 times of rated capacity, and a constant current ratio less than 95% are eliminated, arithmetic mean values of the parameters of the rest lithium ion batteries are calculated, and the rest lithium ion batteries are selected based on following standards, A discharge capacity deviation ranges from +-0.5% to +-3%, B constant current ratio deviation ranges from +-0.2% to +-1%, C internal resistance deviation ranges from +-1% to +-10%, and D open-circuit voltage deviation ranges from +-0.03% to +-0.1%. Operation of the method is simple and convenient, cost is reduced, no extra equipment is needed, and sorting effect is obviously better than that of traditional sorting method.

Description

technical field [0001] The invention relates to a method for sorting lithium ion batteries. Background technique [0002] Lithium-ion batteries have become the preferred power source for electric vehicles and energy storage due to their advantages such as high operating voltage, high energy density, small self-discharge, no memory effect, and high charge-discharge efficiency. In practical applications, single lithium-ion batteries are modularized and grouped through appropriate series and parallel connections, thereby increasing the voltage and capacity of the overall battery pack to meet the power requirements of various fields. In the process of grouping, if the performance of the single cells varies greatly, it will affect the overall performance of the battery pack, greatly reducing the service life of the battery pack, and in severe cases, it will lead to overcharge and overdischarge of the battery, resulting in safety hazards (such as explosions) Wait). Therefore, be...

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Problems solved by technology

In short, although these two sorting methods are simple and convenient to operate, the sorting parameters used are still relatively single, which cannot fully reflect the performance of the battery. The performance consistency of the sorted battery is not high, and the data accuracy is not enough.

[0006] In addition, the patent publication number CN102814292A discloses an AC pulse sorting method; the patent publication number CN103084342A discloses a sorting method based on high-magnification discharge and internal resistance, both of which require additional special equipment If large-scale sorting is to be carried out, the sorting cost must be greatly increased

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