【摘要】：新能源汽車的快速推廣帶動(dòng)了動(dòng)力電池產(chǎn)業(yè)的迅猛發(fā)展,推動(dòng)了相關(guān)產(chǎn)品開發(fā)和前沿課題研究。其中,針對(duì)車載離子動(dòng)力電池及其管理系統(tǒng)的研究是目前各新能源車企、高校及科研機(jī)構(gòu)的研究熱點(diǎn),仍有諸多技術(shù)難題有待攻關(guān)。車載鋰離子電池組由成百上千節(jié)單體電池串并聯(lián)組成,以滿足整車驅(qū)動(dòng)功率和續(xù)航里程的需求。由于單體電池之間的出廠自身參數(shù)不盡相同,以及后期使用環(huán)境、工況條件、自放電率等因素的差異影響,極易導(dǎo)致電池單體間的內(nèi)阻、電壓、容量等內(nèi)外參數(shù)的不一致性,并隨著電池組循環(huán)次數(shù)的增加和逐步老化而累積加重,從而嚴(yán)重影響整個(gè)電池組的可用容量和使用性能,降低整車安全系數(shù)。為解決電池組內(nèi)部各單體間、各模塊間的不一致性問題,提升電池組的壽命周期和性能,延長整車的續(xù)航里程,保證整車運(yùn)行安全,本文針對(duì)車載鋰離子動(dòng)力電池均衡系統(tǒng)及其控制策略展開研究。主要工作包括:(1)分析了鋰離子電池不一致性產(chǎn)生的成因及表現(xiàn),明確了后期使用環(huán)境、工況條件等因素造成的不一致性可以通過能量均衡方式來改善。(2)對(duì)比分析了針對(duì)鋰離子電池的多種均衡電路拓?fù)浞桨?設(shè)計(jì)了一種雙層主動(dòng)均衡電路拓?fù)?底層電路設(shè)計(jì)考慮模塊內(nèi)布局空間及散熱條件有限問題,選用基于升降壓變換的主動(dòng)均衡拓?fù)?具有體積小、易于模塊化及效率高的特點(diǎn);頂層電路設(shè)計(jì)考慮模塊間均衡功率大及模塊數(shù)量多問題,提出一種基于多輸入繞組變壓器的主動(dòng)均衡拓?fù)?具有均衡速度快、均衡控制方式靈活以及易于級(jí)聯(lián)擴(kuò)展的特點(diǎn)。(3)建立了基于Simulink仿真平臺(tái)的均衡系統(tǒng)模型,驗(yàn)證了所設(shè)計(jì)的雙層主動(dòng)均衡電路拓?fù)涞挠行?繼而搭建設(shè)計(jì)了均衡實(shí)驗(yàn)硬件平臺(tái),包括主控單元、電池組信息采集單元、均衡單元等。(4)設(shè)計(jì)了基于壓差和單體電壓等級(jí)的變占空比控制,實(shí)現(xiàn)了對(duì)均衡電流的動(dòng)態(tài)調(diào)節(jié),有效避免了單體電壓波動(dòng)導(dǎo)致的瞬間過充過放現(xiàn)象,縮短了均衡時(shí)間。針對(duì)均衡結(jié)束后電壓恢復(fù)導(dǎo)致的壓差回升現(xiàn)象,提出了基于電池極化電壓的過均衡控制,提升了一致性均衡效果。同時(shí)基于明顯老化電池均衡容易產(chǎn)生的誤均衡問題,提出了基于歷史充電信息和單體電壓上升率的末期均衡策略,有效避免了誤均衡現(xiàn)象。(5)針對(duì)所提出的均衡拓?fù)潆娐愤M(jìn)行實(shí)驗(yàn)驗(yàn)證,分別設(shè)計(jì)并開展了靜置狀態(tài)下和恒流充電工況下的均衡實(shí)驗(yàn);在恒流充電工況下,分別在慢充0.25C和快充0.50C下驗(yàn)證了均衡電路的適用性。實(shí)驗(yàn)結(jié)果表明本文設(shè)計(jì)的車載鋰離子動(dòng)力電池雙層主動(dòng)均衡系統(tǒng)具有很好的均衡效果,有效改善了電池組內(nèi)電壓的不一致現(xiàn)象,提升了可用容量。
[Abstract]:The rapid promotion of new energy vehicles drives the rapid development of power battery industry, and promotes the development of related products and frontier research. Among them, the research on the on-board ion power battery and its management system is the research hotspot of the new energy vehicle enterprises, universities and scientific research institutions at present, and there are still many technical problems to be solved. The lithium-ion battery pack is composed of hundreds of single batteries in series and parallel to meet the requirements of driving power and mileage. Because of the different parameters of the cell, the difference of the environment, the working condition and the rate of self-discharge, it is easy to cause the inconsistency of the internal resistance, voltage, capacity and other internal and external parameters of the cell, such as internal resistance, voltage, capacity and so on. With the increase of cycle times and gradual aging of the battery pack, the accumulative aggravation will seriously affect the available capacity and service performance of the whole battery pack and reduce the safety factor of the whole vehicle. In order to solve the problem of inconsistency between each cell and module in the battery pack, improve the life cycle and performance of the battery pack, prolong the range of the whole vehicle, and ensure the safety of the whole vehicle, In this paper, the equalization system and control strategy of vehicle-mounted lithium-ion battery are studied. The main works are as follows: (1) the causes and manifestations of the inconsistency of lithium ion batteries are analyzed, and the later use environment is defined. The inconsistency caused by operating conditions and other factors can be improved by energy equalization. (2) the topology schemes of various equalization circuits for lithium-ion batteries are compared and a double-layer active equalization circuit topology is designed. The bottom circuit design takes into account the limited layout space and heat dissipation condition in the module, and chooses the active balanced topology based on the lifting voltage transformation, which has the characteristics of small volume, easy modularization and high efficiency. The top-level circuit design takes into account the problems of large equalization power between modules and the number of modules, and proposes an active equalization topology based on multi-input windings transformer, which has high equalization speed. The equalization control mode is flexible and easy to cascade expansion. (3) the equalization system model based on Simulink simulation platform is established to verify the effectiveness of the designed two-layer active equalization circuit topology. Then the hardware platform of the equalization experiment is built, including the main control unit, the battery pack information collection unit, the equalization unit and so on. (4) the variable duty cycle control based on the pressure difference and the cell voltage level is designed. The dynamic regulation of the equalization current is realized, which effectively avoids the transient overcharging caused by the voltage fluctuation of the single unit and shortens the equalization time. Aiming at the recovery of voltage difference caused by voltage recovery after equalization, an over-equalization control based on battery polarization voltage is proposed to improve the consistency equalization effect. Based on the problem of error-equalization caused by obvious aging battery equalization, this paper puts forward a end-stage equalization strategy based on historical charging information and cell voltage rise rate. Effectively avoid the phenomenon of misequalization. (5) the proposed equalization topology circuit is verified experimentally, and the equalization experiments under static state and constant current charging condition are designed and carried out respectively. Under constant current charging condition, the applicability of equalization circuit is verified at slow charging 0.25C and fast charging 0.50C respectively. The experimental results show that the two-layer active equalization system designed in this paper has a good equalization effect, effectively improves the inconsistency of the voltage in the battery pack and increases the available capacity.
【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)：2385982