摘要
以全钒液流电池为研究对象,利用电池内部传递与反应相耦合的机理模型,模拟电池二维、等温、稳态条件下,电池充电过程电极参数对电池内部极化的影响规律,包括碳毡电极的几何结构参数(厚度Lt和压缩比CR)、电学特性参数(比表面积a和电导率σs)和操作参数(充电电流密度i)的影响。数值模拟结果给出Lt从1.5 mm增至3.5 mm,端电压仅降低3 mV;CR从0.1增至0.5,端电压降低16 mV;a从3.5×104 m2/m3增至3.5×106 m2/m3,端电压降低30 mV;σeff s从18.9 S/m增至164.4 S/m,端电压降低87 mV,并给出多孔电极内部过电势在不同σeff s条件下不同的二维分布特点;i从100 mA/cm2增至150 mA/cm2,端电压增大57 mV,若同比增大比表面积a,则端电压只增大46 mV。将数值模拟与宏观实验相对比,取得良好的一致性,表明了数值模拟与分析的可靠性。通过增大CR、a、σeff s可以明显提高电池性能,为进一步提高电极材料的性能、设计电极结构参数、选择操作参数提供了重要依据。
In order to study the all-vanadium redox flow battery （VFB）, a mechanistic model is developed based on the transport and reactions to simulate the effects of various electrode parameters on the battery＇s overall performance and internal polarizations for a VFB charged at isothermal and steady state. The parameters included the carbon felt＇s geometry structure parameters （thickness Lt, Compression ratio CR）, electrical parameters （specific surface area a, electric conductivity o＂s ） and operating parameter （charging current density i）. Numerical simulations showed that when Lt increased from 1.5 mm to 3.5 mm, the terminal voltage drop is 3 mV only; when CR increased from 0.1 to 0.5, the terminal voltage drop is 16 mV; when a increased from 3.5×104 m2.m^-3 to 3.5×10^6 m^2 m^-3, the terminal voltage drop is 30 mV; when δs^eff increased from 18.9 S.m^-1 to 164.4 S.^m-1, the terminal voltage drop is 87 mV, and results also showed different two-dimensional over-potential distribution characteristics under different or δs^eff ; when i increased from 100 mA.crn-2 to 150 mA.cm-2, the terminalvoltage increase is 57 mV, if proportionally increased a, the terminal voltage increase is 46 mV only. Based on the terminal voltage and the over-potential distribution, the reasons for the effects of various parameters on the battery performance are discussed. The experimental validation showed similar results, which proved the reliability of the numerical simulation. Increasing CR, a and o-δs^eff significantly improve the battery performance. This should provide guidance to parameter design and to improve the performance of electrode material, and the improving of battery performances.
出处
《储能科学与技术》
CAS
2014年第4期395-405,共11页
Energy Storage Science and Technology
基金
国家自然科学基金(21276134)
国家863项目(2012AA051203)
关键词
全钒液流电池
数值模拟
多孔介质
电极结构
压缩比
all-vanadium redox flow battery： numerical simulation
porous media： electrode structure.compression ratio
