Screening method for lithium-ion battery consistency

Abstract

The invention relates to the technical field of the detection of a battery, and in particular relates to a screening method for lithium-ion battery consistency. The method is characterized in that the screening is carried out according to the limit capacity, the limit internal resistance and the limit voltage droop in a high-temperature environment, a low-temperature environment or a normal-temperature environment of a single battery; the battery is charged and discharged, so that the screening can be further carried out by comparing the variation of the capacity, the voltages and the currents in the charging and discharging processes, the application efficiency of the single battery can be improved, the service life of the single battery can be prolonged, and the safety of the single battery can be improved.

Description

technical field [0001] The invention relates to the technical field of battery detection, in particular to a screening method for consistency of lithium-ion batteries. Background technique [0002] At present, the green power source with high energy density, long service life and good safety performance - lithium-ion battery is widely used. Lithium-ion batteries are widely used in energy storage, power and other fields. The test found that the service life of the battery pack is lower than that of the single battery for the same battery, which shows that the consistency of the battery obviously affects the service life of the battery. In the series-parallel application of batteries, the consistency of batteries affects the efficiency and life of batteries, and safety issues also have an impact. Therefore, the requirements for the consistency of the single cells assembled into a battery pack should be more stringent. [0003] To ensure the consistency of the battery, first...

AI Technical Summary

Problems solved by technology

[0004] Batteries selected by limiting the capacity range, limiting internal resistance range, and limiting voltage drop at different temperatures can ensure consistent initial performance and self-discharge performance of the battery. It has not been verified whether the charging and discharging of the battery during use are synchronized, and cannot be guaranteed. Consistent decay rate during use

The reason is that the existing battery screening methods cannot reflect the DC internal resistance and polarization internal resistance of the single battery, and the consistency of the battery is flawed.

[0005] Lithium-ion battery packs are composed of multiple single cells connected in series and parallel. However, due to the differences in the performance of each single cell, the performance of the battery pack will decline to varying degrees after a certain charge-discharge cycle, which is manifested as capacity. The acceleration of the attenuation and the difference in the consistency of the single cells in the battery pack become larger, so strict selection must be made before the batteries are assembled

If the consistency of the single cells is not good, the charging and discharging process will increase the difference between the single cells, which will easily cause some batteries to be over-discharged or over-charged, and the performance of the other part of the batteries will not be fully utilized. It will eventually lead to the deterioration of the performance of the battery pack, and the cycle performance of the battery pack will be attenuated or invalid

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