摘要
目的研究高温质子交换膜燃料电池的扩散层孔隙率及其厚度对于提高其性能的影响.方法建立一个二维、单相、稳态数学模型研究高温质子交换膜燃料电池阴极氧气和水蒸气扩散传递规律.模型耦合了质量守恒方程、动量方程、能量方程、组分方程和催化剂层中的Butler-Volmer方程,研究扩散层孔隙率及其厚度对电池阴极中氧气、水蒸气浓度分布的影响.结果在气体流动方向,氧气浓度逐渐降低,水分浓度逐渐升高;从催化剂层到扩散层,氧气浓度逐渐降低,而水分浓度渐渐升高.减小扩散层的厚度和增大扩散层孔隙率,在气体流动方向,氧气浓度降低的梯度变大,水分浓度升高的梯度也越大;在扩散层和催化剂层厚度方向,氧气浓度降低的梯度变小,水分浓度增大的梯度也越小.结论在一定范围内降低扩散层厚度和增大孔隙率有利于氧气的输入和产物水的排出,提高高温质子交换膜燃料电池性能,对高温质子交换膜燃料电池结构参数的优化及电池的推广应用具有重要影响.
This paper studied effects of the diffusion layer porosity and thickness of the HT-PEM fuel cell on cell performances. A two-dimensional, single phase, and steady state mathematical model was developed to study laws of oxygen and water vapor diffusion transfer in the cathode of HT-PEM fuel cell. Based on the mass conservation equation, the momentum equation, the energy and component equation as well as the Bufler-Volmer equation for the catalyst layer, effects of dif- fusion layer porosity and thickness on oxygen concentration and vapour concentration distribution on the cathode of HT-PEM fuel cell were analyzed. It is found that in the gas flow direction, theoxygen concentration decreases, the moisture concentration increases gradually; in the direction from the catalyst layer to the diffusion layer, the oxygen concentration decreases gradually, and the moisture concentration gradually increases. Reducing the diffusion layer thickness and increasing diffusion layer porosity, in the gas flow direction, the decreased gradient of the oxygen concentra- tion becomes large, and the increased gradient of vapour concentration is large; in the direction from the catalyst layer to the layer diffusion, the decreased gradient of the oxygen concentration and the increased gradient of the water concentration become small. Conclusion is that in a certain range, reducing the thickness of diffusion layer and increasing the diffusion layer porosity are con- ducive to the oxygen input and the removal of product water and can improve HT-PEM fuel cell performances. Obtained results are significant for optimizing electrode structure parameters and ap- plication of HT-PEM fuel cell.
出处
《沈阳建筑大学学报（自然科学版）》
CAS
北大核心
2015年第4期698-705,共8页
Journal of Shenyang Jianzhu University：Natural Science
基金
国家自然科学基金项目(51176131
51476107)
