多方向实车振动路谱对电池容量和阻抗特性影响的试验研究

Experimental study on the influence of multi-directional real road spectrum on battery capacity and impedance

针对动力电池特性参数受振动影响会导致其状态估计精度受到干扰而目前又没有统一测试规范的问题,提出一种基于多方向实车振动路谱探究电池模组容量和阻抗特性的试验研究方法。通过分析国内外电池振动测试标准,提出采用实车路谱的必要性,然后设计采集系统获取强化道路下的电池包多方向振动信号,计算其功率谱密度估计,并选取能量集中频率区间分段拟合,构建适用于一般振动台的随机振动曲线。最后搭建了振动放电试验系统,以电池模组为对象还原实车中的安装形式与预紧力,进行振动工况下的标准放电和脉冲特性测试。结果表明:路面激励传递到电池包存在明显能量衰减和敏感方向,电池包振动加速度小于2g且能量集中于50Hz以下;一般的强化道路振动对动力电池放电容量并无明显影响,但会引起直流内阻产生不超过10%的增大。研究结果将为考虑振动因素的动力电池状态估计与故障诊断提供支撑。

The characteristic parameters of power battery influenced by vibration will interfere the state estimation precision,and there is no unified test specification at present.Therefore,an experimental research method based on multi-directional real road spectrum is proposed to analyze the capacity and impedance of battery module.The necessity of using real road spectrum is discussed through analyzing the domestic and foreign battery vibration test standards and specifications.The three-directional acceleration sensors and the data acquisition system are used to obtain the multi-directional vibration signal of the battery pack under the intensified road condition.The concentration frequency section with highly energy distribution is selected for piecewise fitting by calculating the power spectrum density estimation of the original data,and the random vibration curve suitable for general shaker is constructed.The discharge test system under vibration conditions is built,in which the battery modules are applied with the installation form and preload in the actual vehicle,the standard charge-discharge and pulse characteristic tests under vibration conditions are carried out.The results show that there is obvious energy loss and sensitivity direction when the road excitation is transmitted to the battery pack,and the vibration acceleration of the pack is less than 2g and the energy is concentrated in the range of f<50 Hz.The intensified road vibration has no obvious effect on the discharge capacity of the power battery,while it will cause the increase of DC internal resistance by no more than 10%in this experiment.The research results will provide a basis for state estimation and fault diagnosis of power battery considering vibration factors.