發(fā)布時(shí)間：2018-04-22 20:25

  本文選題：鋰離子電池 + 電化學(xué)模型�。� 參考：《哈爾濱工業(yè)大學(xué)》2014年碩士論文

【摘要】：鋰離子電池因性能優(yōu)良而在電子設(shè)備及電動(dòng)車領(lǐng)域得到了廣泛應(yīng)用。在電池的使用過程中，如何預(yù)測(cè)電池的充放電行為具有重要意義，電化學(xué)模型能夠比較準(zhǔn)確的預(yù)測(cè)電池性能，但是傳統(tǒng)電化學(xué)模型存在很多缺陷，尤其中高倍率仿真精度很低，本文對(duì)如何提高P2D電化學(xué)模型的仿真精度進(jìn)行了深入研究，提出了鋰離子電池變參數(shù)模型。 首先，針對(duì)一節(jié)自制的鋰離子電池，通過物理的、電化學(xué)的以及參數(shù)辨識(shí)的方法獲取模型參數(shù)，提出一套完整的參數(shù)獲取方法。采用物理測(cè)量的方法獲取電池結(jié)構(gòu)參數(shù)及設(shè)計(jì)參數(shù)；采用庫侖滴定法獲取材料開路電勢(shì)曲線并通過高斯公式進(jìn)行擬合；采用EIS、PITT、GITT法分別測(cè)量了固相擴(kuò)散系數(shù)并進(jìn)行了比較，結(jié)果PITT與GITT法測(cè)量結(jié)果一致，EIS法測(cè)量結(jié)果較前兩種少一個(gè)數(shù)量級(jí)；采用LSV法測(cè)量了材料反應(yīng)速率常數(shù)，結(jié)果正極反應(yīng)速率常數(shù)變化范圍不大，負(fù)極為分段函數(shù)形式；采用EIS法以及DC/AC法測(cè)量了電解液電導(dǎo)率和陽離子遷移系數(shù)；提出通過0.04C的小電流放電曲線辨識(shí)初始嵌鋰量的方法。 其次，深入分析了粒徑分布、SEI膜內(nèi)阻、變化的反應(yīng)速率常數(shù)、變化的固相擴(kuò)散系數(shù)對(duì)模型的影響，提出了變參數(shù)模型。在粒徑分布上，提出了兩粒度以及三粒度模型，結(jié)果小倍率時(shí)小粒度起主導(dǎo)作用，大倍率時(shí)大粒度起主導(dǎo)作用使放電截止點(diǎn)提前，同時(shí)三粒度模型能夠解釋0.5C以上“拐點(diǎn)”消失的現(xiàn)象；SEI膜的作用相當(dāng)于歐姆內(nèi)阻，相當(dāng)于放電曲線的“平移”，對(duì)放電截止點(diǎn)影響較��；變化的反應(yīng)速率常數(shù)通過改變電流密度分布來影響電壓平臺(tái)，不影響放電截止點(diǎn)；變化的固相擴(kuò)散系數(shù)能夠影響表面與平均的SOC分布，使得電壓平臺(tái)以及放電截止點(diǎn)發(fā)生變化。 最后，對(duì)P2D模型與變參數(shù)模型進(jìn)行仿真并比較，在低倍率時(shí)，P2D模型仿真精度比變參數(shù)模型高，平均誤差不超過10mV；在中倍率時(shí)，變參數(shù)模型的精度遠(yuǎn)遠(yuǎn)高于P2D模型，，誤差不超過18mV(0.5%)，同時(shí)能準(zhǔn)確預(yù)測(cè)放電曲線“拐點(diǎn)”消失的現(xiàn)象；在高倍率時(shí)，變參數(shù)模型平均誤差不超過54mV(1.5%)，因此變參數(shù)模型很大程度地提高了仿真精度。
[Abstract]:Lithium ion batteries have been widely used in electronic equipment and electric vehicles due to their excellent performance. In the process of battery use, how to predict the charge and discharge behavior of the battery is of great significance. The electrochemical model can accurately predict the performance of the battery. However, the traditional electrochemical model has many defects, especially the low precision of high rate simulation. In this paper, how to improve the simulation accuracy of P2D electrochemical model is studied, and the variable parameter model of lithium ion battery is proposed. Firstly, for a self-made lithium ion battery, the model parameters are obtained by physical, electrochemical and parameter identification methods, and a complete set of parameters acquisition method is proposed. The structural parameters and design parameters of the battery were obtained by physical measurement, the open-circuit potential curves of materials were obtained by Coulomb titration and fitted by Gao Si's formula, and the solid diffusion coefficients were measured and compared by EISPITT GITT method. Results the results of PITT and GITT methods were consistent with those of the former two methods. The reaction rate constants of materials were measured by LSV method, and the range of positive reaction rate constants was small, and the negative electrode was a piecewise function. The conductivity and cation transfer coefficient of electrolyte were measured by EIS method and DC/AC method, and the method of identifying the initial lithium intercalation by the low current discharge curve of 0.04C was proposed. Secondly, the influence of particle size distribution on the internal resistance of SEI film, the reaction rate constant and the solid diffusion coefficient are analyzed, and the variable parameter model is proposed. In the particle size distribution, two and three particle size models are proposed. The results show that the small particle size plays the leading role when the small ratio is small, and the large particle size plays the leading role in making the discharge cut-off point advance when the ratio is large. At the same time, the three-particle model can explain the phenomenon of disappearance of "inflection point" above 0.5 C. The effect of SEI film is equivalent to ohmic internal resistance, equivalent to "translation" of discharge curve, and has little effect on the cut-off point of discharge. The varying reaction rate constant affects the voltage platform by changing the current density distribution, and does not affect the discharge cut-off point. The variation of solid diffusion coefficient can affect the surface and average SOC distribution, which makes the voltage platform and the discharge cut-off point change. Finally, the simulation and comparison of P2D model and variable parameter model show that the accuracy of P2D model is higher than that of variable parameter model at low rate, the average error is less than 10 MV, and the accuracy of variable parameter model is much higher than that of P2D model at medium ratio. The error is not more than 18 MV / 0. 5, and the "inflection point" of the discharge curve can be accurately predicted. At high rate, the average error of the variable parameter model is not more than 54 MV / 0. 5, so the simulation accuracy of the variable parameter model is greatly improved.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TM912

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本文編號(hào)：1788780