本文關鍵詞： 鋁空氣電池 電解液 放電產物 添加劑 循環(huán)系統(tǒng)　出處：《哈爾濱工業(yè)大學》2017年碩士論文　論文類型：學位論文

【摘要】：鋁空氣電池是一種具有巨大潛力的金屬空氣電池,它的能量密度遠高于鋰離子電池,它還具有其它二次電池無法比擬的優(yōu)點,當電池中鋁消耗完,可以通過更換鋁板實現“機械式充電”,從而減少了“充電”時間,并且鋁價格低廉,來源廣泛,鋁空氣電池因此引起了人們的關注。然而制約鋁空氣電池長時間使用的因素之一是鋁空氣電池放電產物處理問題,鋁電極在放電過程中,其反應產物為NaAlO_2,當NaAlO_2在電解液中達到一定濃度時便會析出Al(OH)3,在電解液中不易直接濾除,從而會帶來一系列嚴重的問題。首先大量的NaAlO_2會嚴重影響電解液的黏度和電導率,電解液電導率的下降,會增加鋁空氣電池的溶液的電阻,電池的放電性能衰減;電解液變粘,嚴重時呈黏糊狀,極大影響電解液使用壽命,不利于放電過程中生成的氣體排出和反應物的擴散,并且對鋁空氣電堆中電解液的循環(huán)帶來一定的負擔。本論文中研究了鋁空氣電解液中反應產物NaAlO_2對電解液物理性質的改變,分析NaAlO_2濃度對鋁電極、空氣電極以及電池性能的影響規(guī)律,證實電解液中飽和NaAlO_2會使鋁空氣電池最大功率下降約15%;F-對鋁電極的電化學行為有顯著的影響,通過使用NaF作為添加劑提升鋁電極在電解液中電化學性能從而降低NaAlO_2對鋁空氣電池的有害影響;此外論文中利用電解鋁,分析鋁電極在電解液中析出的Al(OH)3顆粒,其顆粒大小集中在1μm到20μm之間,并且使用水力旋流器設計了一套鋁空氣電解液循環(huán)系統(tǒng),它可以將鋁空氣電堆在放電過程中生成的Al(OH)3顆粒進行收集,當水力旋流器進口流量的增加,該系統(tǒng)收集Al(OH)3顆粒的能力出現先增大后減小的趨勢,當水力旋流器進口流量為0.67 L/min時Al(OH)3顆粒收集率最大30 min內可達84%,整個循環(huán)系統(tǒng)的能耗在6 W左右,具有結構簡單,能耗少等優(yōu)點。論文中首次將聚丙烯酰胺(PAM)應用于鋁空氣電池電解液中,PAM在電解液中的使用可以增加電解液的黏度,但不會改變電解液的電導率,從而不會改變電池內阻并且對空氣電極和鋁電極電化學性能影響較小。PAM在電解液中具有絮凝作用能加快Al(OH)3顆粒在電解液中的沉降速度,使Al(OH)3顆粒在短時間快速沉降到電解液桶底部從而達到沉降分離;PAM在電解液中具有增稠性,增加電解液的黏度但仍具有較好的流動性,可以將鋁空氣單體內腔生產的Al(OH)3顆粒粘黏在電解液中,隨著電解液的流動全部帶出單體內腔,避免Al(OH)3顆粒在單體內腔堆積,極大延長空氣電極壽命。
[Abstract]:Aluminum air battery is a kind of metal air battery with great potential. Its energy density is much higher than that of lithium ion battery. "Mechanical charging" can be achieved by replacing aluminum sheets, thus reducing "charging" time, and aluminum is cheap and widely available. However, one of the factors restricting the long-term use of aluminum air battery is the disposal of the discharge product of the aluminum air battery, the aluminum electrode in the discharge process. The product of the reaction is NaAlO2. when NaAlO_2 reaches a certain concentration in the electrolyte, it will precipitate AlOH3, which is not easy to be filtered directly in the electrolyte. First, a large number of NaAlO_2 will seriously affect the viscosity and conductivity of the electrolyte. The decrease of the electrolyte conductivity will increase the resistance of the aluminum air battery solution. The performance attenuation of battery discharge; When the electrolyte becomes sticky, it becomes sticky and paste, which greatly affects the service life of the electrolyte, and is not conducive to the discharge of gases and the diffusion of reactants in the discharge process. And it brings a certain burden to the circulation of electrolyte in the aluminum air stack. In this paper, the change of the physical properties of the electrolyte produced by the reaction product NaAlO_2 in the aluminum air electrolyte has been studied. The effect of NaAlO_2 concentration on the performance of aluminum electrode, air electrode and battery is analyzed. It is proved that saturated NaAlO_2 in electrolyte can decrease the maximum power of aluminum air battery by about 15%. F- has a significant effect on the electrochemical behavior of aluminum electrode. By using NaF as additive, the electrochemical properties of aluminum electrode in electrolyte can be improved to reduce the harmful effect of NaAlO_2 on aluminum air battery. In addition, aluminum electrolysis is used to analyze the Al(OH)3 particles precipitated from aluminum electrode in electrolyte. The size of the particles is between 1 渭 m and 20 渭 m. A set of aluminum air electrolyte circulation system is designed by using hydrocyclone, which can collect the Al(OH)3 particles generated in the discharge process of the aluminum air stack. When the inlet flow rate of hydrocyclone increases, the capacity of collecting Al(OH)3 particles in the system increases first and then decreases. When the inlet flow rate of hydrocyclone is 0.67 L / min, the Al(OH)3 particle collection rate can reach 84% within 30 min, and the energy consumption of the whole circulatory system is about 6 W. It has the advantages of simple structure and less energy consumption. In this paper, the application of PAM in the electrolyte of aluminum air battery for the first time can increase the viscosity of the electrolyte. But it doesn't change the conductivity of the electrolyte. So it can not change the internal resistance of the battery and has little effect on the electrochemical performance of the air electrode and aluminum electrode. The flocculation of Al(OH)3 particles in the electrolyte can accelerate the settling rate of Al(OH)3 particles in the electrolyte. The Al(OH)3 particles can be precipitated to the bottom of the electrolyte bucket in a short time. PAM has thickening property in the electrolyte, increases the viscosity of the electrolyte but still has good fluidity, and can stick the Al(OH)3 particles produced in the inner cavity of aluminum air monomer to the electrolyte. With the flow of electrolyte, the monomeric cavity is brought out, and the accumulation of Al(OH)3 particles in the monomer cavity is avoided, which greatly prolongs the life of air electrode.
【學位授予單位】：哈爾濱工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TM911.41
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本文編號：1474319