露天静止停放对汽车动力锂离子电池的性能影响研究

A Research on the Influence of Outdoor Stationary Parking on the Performance of Li-Ion Traction Batteries in Electric Vehicles

本文利用整车自然曝露试验,考察了长时间露天停放对新能源汽车动力电池包电池容量的影响,并对电池包进行拆解,随机取样2只电芯进行电化学阻抗谱分析电芯一致性变化情况。整车自然曝露试验过程中,每3个月对动力电池系统进行一次标准化的室温容量测试。充放电过程中不同荷电状态(SOC)或不同温度条件下电芯阻抗谱特性来比较不同电池的老化程度。结果表明,试验车动力电池包容量明显下降、一年后降低到初始的92.21%;一年期自然曝露试验结束后,针对拆解取样电芯进一步对比慢充、放电、快充过程中SOC处于0、20%、50%、80%阶段,以及20%SOC状态下处于-35℃、0℃、25℃、45℃环境温度时的电化学阻抗谱,重点分析模值和相位角曲线吻合度,结果表明试验后电池单体的一致性变化明显,其中温度的影响最为显著。综合来看,露天静止停放对动力电池服役寿命有较大影响。

In this paper,the influence of long time outdoor parking on the capacity of the traction battery pack of new energy vehicles was investigated by the natural exposure test of the whole vehicle.Randomly select two cells from the disassembled battery pack of the test vehicle,and perform electrochemical impedance spectroscopy analysis to compare the cell inconsistency.During the natural exposure test of the whole vehicle,the capacity of traction battery system is tested with a standardized method at room temperature every 3 months.Results show that the capacity of the traction battery pack of the test vehicle reduced significantly to 92.21% of the initial level after one year test.After the one-year natural exposure test,the modulus and phase angle curve in the electrochemical impedance spectrum was further compared with the SOC at 0,20%,50% and 80% during the slow charge,discharge and fast charging process,and the ambient temperature of -35℃,0℃,25℃and 45℃ at 20% SOC state.And that the consistency of the battery cell after the test has experienced noticeable changes,and the influence of temperature was the most significant.On the whole,outdoor static parking has a great impact on the service life of traction battery.