A battery pack segmented mixing equalization control method

Abstract

A method for segmented hybrid equalization control of a battery pack is disclosed. The method comprises the following steps: S0. judging whether each single cell of the battery pack satisfies VL<Vi<VHand whether the battery pack satisfies 0<SOCmin>=SOCmax<1 at the same time. If the battery pack satisfies the two formulae at the same time, the method proceeds to step S1, otherwise, the charging and discharging balance is not carried out, and the method ends; S1. In the battery pack voltage plateau period, the single cell with the largest SOC is used as the balancing object and the SOC is usedas the balancing control variable to perform the balancing control, and in the battery pack voltage non-plateau period, the single cell with the largest voltage is used as the balancing object and thevoltage is used as the balancing control variable to perform the balancing control. Wherein VL is the cell discharge cutoff voltage, VH is the cell charge cutoff voltage, and Vi is the voltage of theith cell in the battery pack; SOCmin and SOCmax are the minimum and maximum values of SOC of each cell in the battery pack respectively.

Description

technical field [0001] The invention belongs to the field of electrochemical energy storage, and more specifically relates to a method for controlling segmental mixing balance of battery packs. Background technique [0002] Large-scale energy storage technology is a key technology for building a grid with high penetration rate of renewable energy and realizing the sustainable development of electric energy. At present, a variety of energy storage technologies have been widely studied, among which battery energy storage technology has broad application prospects in the field of large-scale energy storage due to its technical maturity and excellent comprehensive performance. In a battery energy storage system, it is necessary to connect single cells in series and parallel to form a group to meet the voltage and capacity level requirements of a large-capacity energy storage system. Due to the differences in the manufacturing process and use environment between single cells, th...

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Problems solved by technology

[0005] Aiming at the defects of the prior art, the present invention provides a battery pack segmented hybrid equalization control method, the purpose of which is to take the voltage as the balance control variable when the battery is in the voltage non-plateau period, and use the SOC as the balance control variable when the battery is in the voltage plateau period. The control method of the control variable is used to solve the problems of low equalization efficiency caused by the characteristics of wide and flat battery voltage platform, fast voltage change during the non-plateau period, and insufficient SOC estimation accuracy that affects the equalization effect.

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