Dynamically-reconfigurable battery energy storage system and method

Abstract

The invention relates to a dynamically-reconfigurable battery energy storage system and method. The system comprises an energy storage system main circuit and a battery management system. The energy storage system main circuit has a charging and discharging interface circuit and an energy storage battery pack connected with the charging and discharging interface circuit. The energy storage battery pack is formed by connecting a plurality of single batteries in parallel. Each single battery is provided with a controllable switch Sn(n=1, 2,..., n) at the two ends thereof. In the energy storage battery pack formed by connecting the plurality of single batteries in parallel, the positive electrode end of each single battery is connected with the positive electrode end of an adjacent single battery through a controllable switch S'n (n = 1, 2,..., n), and the negative electrode end of each single battery is connected with the negative electrode end of the adjacent single battery through a controllable switch S "n (n = 1, 2,..., n). The battery management system is connected with the energy storage system main circuit, and is used for generating an energy storage battery pack reconfiguration decision according to electrical information of the single batteries and a power switching instruction, and controlling connection or disconnection of the controllable switch Sn, the controllable switch S'n and the controllable switch S"n to change topology of the energy storage battery pack.

Description

technical field [0001] The invention belongs to the field of construction and control of battery energy storage systems, in particular to a dynamically reconfigurable battery energy storage system and method. Background technique [0002] With the gradual depletion of fossil energy and the increasing concern of human beings on environmental issues, clean and renewable energy power generation is rapidly expanding, and a new round of energy transformation is gradually advancing. However, renewable energy has inherent characteristics of volatility and randomness, which pose many challenges to the safe, stable, and economical operation of the power grid. Energy storage technology is an effective means to deal with the above challenges, and building a large-scale economical energy storage system is a significant research topic. In addition to pumped storage, battery energy storage is the energy storage technology with the most promising engineering application prospects at this ...

AI Technical Summary

Problems solved by technology

[0003] Traditionally, the battery energy storage system connects battery cells in series and parallel in a fixed way to expand the energy storage capacity and power of the energy storage system. This has two disadvantages: (1) The energy storage system has a short board effect, which makes it difficult to fully Utilizes the energy storage capacity of all battery cells

For example, the charge and discharge ampere hours of a battery pack composed of multiple battery cells connected in series are equal to the battery cell with the least ampere hour, so the energy storage capacity of the battery cell with a larger ampere hour is not fully utilized

(2) There is an unbalanced effect in the energy storage system, which leads to significant differences in the aging degree and speed of the battery cells, shortening the overall life of the energy storage system

The difference in parameters will lead to unbalanced charging and discharging conditions of each cell in the battery pack, which will lead to differences in the aging of battery cells, and further increase the difference in parameters, causing a greater degree of unbalanced working conditions

Therefore, the differences in battery cell parameters and aging differences promote each other to form a positive feedback process, which eventually leads to serious aging of some cells and small aging of some cells due to low usage, which in turn affects the overall life of the energy storage system.

[0004] It can be seen from the above that the battery energy storage system using the fixed connection method lacks flexible adjustment space, and it is difficult to give full play to the adjustment function of the battery management system. The battery utilization rate is low and unbalanced, and there is a lot of room for improvement.

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