本文關(guān)鍵詞： 鋰離子電池 脈沖充電 分段充電 遺傳算法 田口方法　出處：《山東大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：為應(yīng)對(duì)環(huán)境和能源危機(jī),新能源電動(dòng)汽車取代傳統(tǒng)燃油汽車的趨勢(shì)不可避免。在政策和市場(chǎng)的驅(qū)動(dòng)下,我國(guó)電動(dòng)汽車近年來呈爆發(fā)式增長(zhǎng)的趨勢(shì)。動(dòng)力電池作為電動(dòng)汽車的動(dòng)力源泉,直接影響電動(dòng)汽車的性能和壽命。其中鋰離子動(dòng)力電池以其比能量高、自放電率低、循環(huán)壽命長(zhǎng)等特點(diǎn)脫穎而出,成為電動(dòng)汽車動(dòng)力電池的首選目標(biāo)。然而,鋰離子動(dòng)力電池的容量、充電速度和壽命仍是制約電動(dòng)汽車發(fā)展的關(guān)鍵因素,相關(guān)技術(shù)水平亟待提高。本文通過實(shí)驗(yàn)對(duì)比分析幾種常用充電策略對(duì)電池的影響,結(jié)合電池的內(nèi)阻特性,最終把針對(duì)恒流階段的分段充電策略作為研究對(duì)象;基于遺傳算法的分段智能充電策略能根據(jù)電池內(nèi)阻的變化調(diào)整充電電流,在不降低充電速度的同時(shí)提高充電效率;根據(jù)無(wú)析鋰快速充電原理改進(jìn)的分段充電能夠降低充電過程中出現(xiàn)析鋰的可能性。具體的工作內(nèi)容主要包括以下幾個(gè)方面:1、分析現(xiàn)有的鋰離子充電技術(shù),對(duì)恒流恒壓充電、多段恒流充電和脈沖充電進(jìn)行實(shí)驗(yàn)研究。理論分析和實(shí)驗(yàn)結(jié)果表明:電池端電壓達(dá)到截止電壓后恒壓充電是最快的充電方法,針對(duì)恒壓階段的多段恒流充電只能縮短充電時(shí)間,不能提高充電速度;脈沖充電與電流平均值相同的恒流充電相比,不能提高充電速度但會(huì)使電池提前達(dá)到截止電壓,縮短充電時(shí)間,減少充入電量,并導(dǎo)致電池溫度升高;"最小阻抗頻率"是對(duì)充電電流中交流成分的優(yōu)化,而交流成分本身對(duì)充電無(wú)益。2、建立鋰電池的二階RC等效電路模型,并在其基礎(chǔ)上構(gòu)建能耗模型,通過HPPC實(shí)驗(yàn)辨識(shí)模型參數(shù),并在Matlab中驗(yàn)證了模型的有效性�？紤]到電池內(nèi)阻隨SOC變化,本文將電池的內(nèi)阻能耗作為目標(biāo)函數(shù),在能耗模型的基礎(chǔ)上采用遺傳算法對(duì)分段充電進(jìn)行優(yōu)化。仿真結(jié)果表明電池內(nèi)阻變化越大、充電分段越精細(xì),分段充電對(duì)能耗的優(yōu)化效果越好。對(duì)于三元電池,在每5%一個(gè)階段的情況下,能夠降低2.2%的能耗。最后充電實(shí)驗(yàn)的結(jié)果驗(yàn)證了分段充電的有效性。3、內(nèi)部析鋰是影響電池壽命的重要因素,理論上將電池負(fù)極表面的鋰離子濃度維持在飽和濃度能夠?qū)崿F(xiàn)鋰離子電池的無(wú)析鋰快速充電。本文參照該理論改進(jìn)分段充電的分段方法,結(jié)合所用的電池,在0-40%SOC的階段采用最大電流2C充電使鋰離子濃度迅速趨于飽和,之后每10%一個(gè)階段,充電電流不斷下降以維持飽和濃度,直到80%SOC。采用田口方法設(shè)計(jì)實(shí)驗(yàn),以充電時(shí)間、功耗和電池溫度的加權(quán)和為價(jià)值函數(shù),分析實(shí)驗(yàn)數(shù)據(jù)得到了后四個(gè)階段的最優(yōu)電流值。最后設(shè)計(jì)實(shí)驗(yàn)進(jìn)行驗(yàn)證。
[Abstract]:In order to cope with the environmental and energy crisis, the trend of replacing traditional fuel vehicles with new energy electric vehicles is inevitable, driven by policies and markets. As the power source of electric vehicles, power battery has a direct impact on the performance and life of electric vehicles in recent years, among which the lithium ion battery has a high specific energy. The characteristics of low self-discharge rate and long cycle life stand out and become the preferred target of electric vehicle power battery. However, the capacity of lithium ion battery. Charging speed and life are still the key factors restricting the development of electric vehicles, and the related technical level needs to be improved. This paper analyzes the influence of several common charging strategies on the battery through experiments, combining with the characteristics of battery internal resistance. Finally, the piecewise charging strategy for the constant current stage is taken as the research object. The intelligent charging strategy based on genetic algorithm can adjust the charging current according to the change of battery internal resistance and improve the charging efficiency while not reducing the charging speed. According to the principle of rapid charging without lithium evolution, the piecewise charging can reduce the possibility of lithium evolution during the charging process. The specific work includes the following aspects: 1, analyzes the existing lithium ion charging technology. The theoretical analysis and experimental results show that constant voltage charging is the fastest charging method when the terminal voltage of the battery reaches the cut-off voltage. Multi-stage constant current charging at constant voltage stage can only shorten the charging time and can not improve the charging speed. Compared with the constant current charging with the same average current, pulse charging can not improve the charging speed, but will make the battery reach the cut-off voltage ahead of time, shorten the charging time, reduce the charge charge, and lead to the increase of battery temperature. The "minimum impedance frequency" is the optimization of the AC component in the charging current, and the AC component itself is not beneficial to charging. The second-order RC equivalent circuit model of the lithium battery is established, and the energy consumption model is constructed on the basis of the model. The model parameters are identified by HPPC experiment, and the validity of the model is verified in Matlab. Considering the change of battery internal resistance with SOC, the energy consumption of battery internal resistance is taken as the objective function in this paper. On the basis of the energy consumption model, genetic algorithm is used to optimize the battery charging. The simulation results show that the larger the battery resistance change, the more fine the charging section, the better the energy consumption optimization effect. For the ternary battery. At every 5% stages, the energy consumption of 2.2% can be reduced. Finally, the results of the charging experiment verify the effectiveness of subsection charging. The internal lithium evolution is an important factor affecting the battery life. In theory, the lithium ion concentration on the anode surface of the battery can be kept at saturation concentration to realize the rapid charging of lithium free lithium ion battery. According to this theory, the piecewise charging method is improved, and the battery used is combined. In the 0-40SOC stage, the maximum current 2C charge makes the lithium ion concentration rapidly saturated, and then every 10% stage, the charge current decreases continuously to maintain the saturation concentration. The experiment was designed by using the Taguchi method, and the value function was the weighted sum of charging time, power consumption and battery temperature. The optimal current value of the last four stages is obtained by analyzing the experimental data. Finally, the experiment is designed to verify it.
【學(xué)位授予單位】：山東大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TM912

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本文編號(hào)：1447890