梯次利用电池储能系统一致性维护方法研究

Research on Consistency Maintenance Method for Echelon Use Battery Energy Storage System

梯次利用电池储能系统与常规储能系统相比,面临更加困难的维护工作,需要研究高效的梯次利用电池储能系统维护方法 ,而维护工作的目的之一就是维护电池间的一致性。动力电池退役后应用于储能系统,相比传统新电池储能电站,电池一致性发散问题更为突出。随机抽取两组某纯电动公交车退役电池模组作为试验样本,测试电池模块剩余容量、欧姆内阻等参数,分析欧姆内阻的不一致性和SOC使用区间的不一致性对容量的影响。经分析,被测试退役电池在循环过程中,欧姆内阻没有明显增大趋势,容量的衰退主要由单体电池容量不一致性导致。然后提出一种基于抽样试验的梯次利用电池储能系统维护关键指标确定方法 ,并通过试验证明了该方法的有效性。通过数据分析,抽样电池模块在后期循环中,欧姆内阻一致性没有太大变化,但是SOC使用区间变化较大,尤其是高端SOC区间容量利用率随着循环次数的增加逐渐降低,影响了电池模块的可用容量,是维护中要重点关注的部分。

Compared with traditional energy storage system,echelon use battery energy storage system is more difficult to maintain,so the research on effective maintenance method for echelon use battery energy storage system is required and one purpose of such maintenance is to keep the consistency between batteries.When decommissioned power battery is applied to energy storage system, the divergence problem of battery consistency is more prominent than the traditional new battery energy storage power station.In this paper,two groups of decommissioned battery modules from a pure electric bus are randomly picked as the samples to test the parameters of battery module such as residual capacity and ohm resistance and analyze the impact of ohm resistance inconsistency and SOC use interval inconsistency on the capacity.It is found that there is no significant increase in the ohm resistance during the cycling of the tested decommissioned batteries ,and the capacity decay is mainly caused by the inconsistency of single battery capacity.Then a method for identifying the key indicators of maintenance of echelon use battery energy storage system based on sampling test is suggested,and its validity is verified via the tests.Based on data analysis,there is no significant change in the consistency of ohm resistance during the later-stage cycling of the sampled battery modules ,but the SOC use interval changes a lot,and the capacity utilization ratio of high-end SOC interval decreases as the cycling times increases,influencing the available capacity of the battery modules.This is the focus of attention during the maintenance.