基于退役锂动力电池容量、内阻和荷电状态的建模与参数估计

发布时间：2018-03-02 23:20

本文选题：退役锂动力电池　切入点：一致性分选　出处：《中南大学》2014年博士论文　论文类型：学位论文

【摘要】：摘要：从电动汽车上退役下来的锂离子动力电池(简称退役电池)仍具有高达80%的剩余容量,研究剩余容量的再利用技术对间接降低锂动力电池成本与缓解环境污染问题有着重要的意义。为了最大限度发挥退役电池的价值,对其进行分选以及对具有利用价值的电池进行剩余寿命等方面的研究非常必要,这也是目前退役电池梯级利用及回收领域的热点课题之一。本文采用电化学检测-计算机模拟联合技术研究了电池在不同温度、放电倍率和放电深度下的电化学行为；针对电池的剩余寿命,劣化失效程度和荷电状态进行分析和估计,建立了电池寿命预测模型、劣化失效的普适模型和荷电状态估计模型,为确保退役电池安全、可靠地运行并保持在最佳工作状态提供了理论指导。通过对上述内容的深入研究,获得了以下四个方面的研究结果： (1)采用现代物理测试技术和电化学检测手段对退役电池进行了安全性能检测,并结合外观/容量分选法、电压/内阻分选法及特征曲线法对退役的18650型磷酸铁锂动力电池进行了分选。本论文分选出了外观无破损特征,容量在1.1～1.0Ah,内阻在12～12.6mΩ,开路电压在3.2998-3.3002V,以及大倍率放电时,放电曲线一致性较好的退役电池作为研究对象。 (2)采用电化学检测-计算机模拟联合技术建立了退役电池的寿命预测模型,并提出了一种退役电池的寿命匹配检测方法。电化学检测结果表明：影响退役电池循环寿命的主要因素为循环次数(N),环境温度(T),放电倍率(C)和放电深度(DOD)。退役电池的放电容量随着循环次数的增加逐渐降低,环境温度越高,放电倍率越大,放电深度越深,退役电池的放电容量衰减越快。当循环时间足够长时,放电深度对退役电池寿命的衰减影响不大。计算机模拟结果表明：退役电池的放电容量衰减速率随循环次数,环境温度,放电倍率和放电深度的变化规律符合幂函数模型：以此为标准模型,采用匹配检测技术可利用较少的容量保持率与循环次数的数据对,准确地预测出任意一颗同规格退役电池当前所处的工况,以及在该工况时退役电池的剩余寿命。 (3)采用内阻-交流阻抗联合检测技术建立了退役电池的劣化失效模型。结果表明：内阻可用来表征退役电池的劣化失效程度。随着内阻的增加,退役电池劣化程度加剧。欧姆内阻和极化内阻的变化与环境温度、放电倍率和放电深度有关。环境温度的升高,放电深度的加深以及放电倍率的增大均会导致内阻加快增长。三种因素对欧姆内阻和极化内阻影响的重要程度为：放电深度放电倍率环境温度。欧姆内阻与极化内阻之和与循环次数的关系符合幂函数模型： (4)采用交流阻抗测定法、SOC-OCV曲线法和脉冲放电法相结合的方法建立了退役电池荷电状态估计模型。交流阻抗测试结果表明：对退役电池进行全荷电态建模时,应同时考虑欧姆内阻和极化内阻对退役电池荷电状态的影响。而对退役电池进行区间段建模时,主要考虑极化内阻对荷电状态的影响。SOC-OCV测试结果表明：退役电池的SOC-OCV特性不受环境温度,放电倍率,储存时间及电池充放电状态的影响,退役电池的OCV随着SOC的递增而单调递增,随着SOC的递减而单调递减。等荷电态多步脉冲放电法测试结果表明：通过所建立退役电池的等效电路模型,可确定退役电池OCV关于SOC的模型,从而估算SOC值。
[Abstract]:Abstract: lithium ion battery retired from the electric car (the retired battery) still has residual capacity of up to 80%, and then use the residual capacity of technology research is of great significance to reduce the cost of lithium batteries and indirectly alleviate environmental pollution. In order to maximize the value of the battery sorting retired. On and on the value of the battery is very necessary to carry out research on the residual life of the battery, which is currently retired and recovery of cascade utilization is one of the hot topics field. This paper uses the electrochemical detection technology was studied to calculate the joint battery in different temperature simulator, the electrochemical behavior of the discharge rate and depth of discharge for the remaining life; battery, analysis and estimation of the deterioration degree and state of charge, to establish a prediction model of battery life, deterioration of the universal model and The state estimation model provides a theoretical guidance for ensuring the safety of the decommissioning batteries, reliable operation and keeping the best working condition. Through the in-depth study of the above contents, we get the following four research results.
(1) the modern physical test and electrochemical detection by means of the safety inspection of retired batteries, and combined with the appearance / sorting capacity, voltage / resistance sorting method and the method of characteristic curves for retired 18650 type lithium iron phosphate battery was separated. This paper selected appearance without damage characteristics, capacity 1.1 ~ 1.0Ah, 12 ~ 12.6m ohm resistance, open circuit voltage in 3.2998-3.3002V, and the high rate discharge, the discharge curve of the battery retired better as the research object.
(2) prediction model using electrochemical detection computer established cell simulation technology combined with retired life, and put forward the detection method, a retired battery life. The electrochemical detection results show that the main factors affecting retirement for the battery cycle life cycles (N), ambient temperature (T), discharge rate (C) and the depth of discharge (DOD). The discharge capacity of the battery retired gradually decreased with the increase of cycle number, the higher the temperature, the greater the discharge rate, discharge depth, discharge capacity of the battery attenuation retired faster. When the cycle time is long enough, the depth of discharge of retired battery life is not affected. Computer simulation of attenuation the results show that the discharge capacity of the battery decommissioning decay rate with the number of cycles, the environment temperature variation, discharge rate and discharge depth with power function model:
Taking this as a standard model, the matching detection technology can be used to predict the current working condition of any same specification decommissioning battery accurately, and the remaining life of the decommissioned battery under this condition can be accurately predicted by using fewer data of capacity retention rate and cycle number.
(3) a retired battery deterioration through joint detection resistance - impedance failure model. The results show that the degradation can be used to characterize the internal resistance of the battery failure. Retired with resistance increases, retired battery deterioration increased. Changes of the ohmic resistance and polarization resistance and environmental temperature, discharge rate and discharge depth related to the increase of environmental temperature, discharge depth and increase the discharge rate will cause the resistance to accelerate growth. The degree of importance of the three kinds of factors of ohmic resistance and polarization resistance for the depth of discharge and discharge rate temperature. Ohmic resistance and polarization resistance and the number of cycles with the power function model:
(4) determination by AC impedance method combining SOC-OCV curve method and pulse discharge method is proposed to estimate the state of charge of battery model retired. AC impedance test results show that the full state of charge of battery modeling retired, should take into account the influence of the ohmic resistance and polarization resistance state of charge of retired batteries. The interval model of the retired battery, mainly consider the polarization resistance effect on the state of charge of the.SOC-OCV test results show that the SOC-OCV characteristics of retired battery is not affected by environment temperature, discharge rate, storage time and battery state of charge and discharge the battery with SOC OCV, retired increases monotonically, with the decline of SOC monotonously charged. Multi step pulse discharge test results show that the equivalent circuit model of the battery can be determined to retire, retired battery OCV on the SOC model, thus Estimate the SOC value.

【学位授予单位】：中南大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM912

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