为探究全钒液流电池(VRFB)碳毡微观尺度下承受压力的位移变形并量化其对传输特性的影响,应用X射线断层扫描(XCT)微观重构技术、有限元方法(FEM)和孔尺度模拟技术(PSM),考虑碳纤维间受压缩的接触摩擦及挤压弯曲,重构了碳纤维微观结构,研究了碳纤维不同压缩比3D(X、Y和Z方向)位移分布,并量化位移变形对微结构传输特性的影响。结果表明：随着压缩比增大到30%,Z方向位移变化最为明显,位移变化为-59~+5μm,X、Y方向位移变化为-25~+16μm,钒离子XY方向扩散系数减小15.4%,Z方向扩散系数减小24.2%,XY方向电导率升高102.1%,Z方向电导率增大46.2%,且随着压缩比大于20%,扩散系数和Z方向电导率变化速度增大。

X-ray computed tomography (XCT) reconstruction technique, finite element method (FEM) and pore scale modelling (PSM) were employed to investigate the displacement distribution and its effects on transport properties of vanadium redox flow battery (VRFB) carbon felt under compression at pore-scale. Contact, friction, extrusion and bending were considered between carbon fibers. Micro-structure of a carbon felt was reconstructed by XCT first, then the displacement distribution of the microstructure in 3D (X, Y and Z direction) with different compression ratio (CR) were investigated, and last the relationship between the displacement and transport properties was quanlificated. The results show that the carbon fibers’ displacement in the Z direction (through plane) under compression is more noticeable. As CR was increased to 30%, the displacement change in Z direction is -59~+5μm, and in XY directions (in-plane) is -25~+ 16μm, the diffusion coefficient of the vanadium ion in XY direction is decreased by 15.4%, and in Z direction is decreased by 24.2%. The conductivity in XY direction is increased by 102.1%, and in Z direction increases by 46.2%. As CR is increased from 20% to 30%, the diffusion coefficient and the conductivity change faster.

TM911.3

国家重点研发计划(2017YFB0102702),国家留学基金委CSC资助(201906950062),中央高校基本科研业务费资助