Equalization method for improving capacity consistency of series lithium ion battery pack

Abstract

The invention relates to an equalization method for improving capacity consistency of a series lithium ion battery pack. The equalization method comprises the following steps: 1) determining a worst single battery; 2) charging the series lithium ion battery pack, and stopping charging until the first single battery reaches the charging cut-off voltage; 3) acquiring an SOC starting point of the worst single battery; 4) discharging until the first single battery reaches the discharge cut-off voltage; 5) adjusting the SOC starting point of the worst single battery to be at the optimal SOC starting point, setting the worst single battery as the optimal SOC starting point after each charge-discharge cycle, and setting the SOC of the other single batteries to be 100%; and 6) when the capacity ofone single battery is consistent with that of the worst single battery in the charge-discharge cycle process, adjusting the optimal SOC starting points of the single battery and the worst single battery to be the same, and repeating the steps 2)-4). Compared with the prior art, the method has the advantages of simple operation, easy implementation, high feasibility and the like.

Description

technical field [0001] The invention relates to the field of lithium-ion battery management, in particular to an equalization method for improving the capacity consistency of series-connected lithium-ion battery packs. Background technique [0002] As a major energy source of the current energy storage system, the battery system's performance directly affects the service life of electrical appliances. Lithium-ion batteries have been widely used due to their advantages such as high energy density, high working voltage, long cycle life, and no memory. The life of the battery system is one of the bottlenecks restricting the development of lithium-ion batteries, and the inconsistency of the life of single cells in the battery system reduces the overall life of lithium-ion batteries due to the "short plate effect". [0003] At present, the commonly used equalization strategies aimed at maximizing the single discharge capacity of lithium-ion battery packs are conventional top equ...

AI Technical Summary

Problems solved by technology

Under these two equalization methods, the inconsistency of the lithium-ion battery pack maintained an upward trend, that is, the consistency of the lithium-ion battery pack was deteriorating, indicating that neither the conventional top equalization nor the bottom equalization had broken the deterioration in the lithium-ion battery pack. circular effect

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