A novel design of reconfigurable multicell for large-scale battery packs

Battery packs consisting of a great number of battery cells are becoming more and more widely used, such as 220kV transformer substation, and large-scale energy storage system in the power grid. However, low energy efficiency, short service life, potential safety hazards as well as low flexibility and reliability have become bottlenecks in conventional utilized battery packs for practical applications. This paper presents a novel design of recon figure able battery packs, in which each battery cell can be connected in series, in parallel or bypassed via switch matrix. By appropriate control signals on switches, battery cells can be configured to different configurations to meet several requirements, including capacity maximization, stable output voltage, cell balancing, weak/faulty cell replacement, etc. Compared with other reconfigurable structure with the same function, the proposed design reduces the number of required switches by 20%. It is verified by simulation results that the proposed design can significantly improve the performance of battery packs.