不同温湿度对质子交换膜燃料电池性能的影响

Effects of different temperatures and humidity on the performance of proton exchange membrane fuel cells

为研究不同温湿度对质子交换膜燃料电池(proton exchange membrane fuel cell,PEMFC)性能的影响,提出了一个温湿度-电流(temperature and relative humidity-current,TRH-C)模型。该模型纳入阴阳极流道的水流量和膜水含量,揭示了电流阶跃变化条件下温湿度对电流密度分布和膜水含量分布的影响规律。根据实验单电池真实的流道构型,建立了简化的PEMFC几何模型并划分计算网格,将TRH-C模型耦合至多物理场计算软件COMSOL中;建立了PEMFC测试平台,对不同温湿度工况下的PEMFC进行了测试,PEMFC的运行温度为65℃和70℃、进气湿度为50%和75%;分析讨论了不同工况下的极化曲线、膜电流密度分布和膜水含量分布云图。研究结果显示:TRH-C模型对PEMFC输出性能的预测较为精准,其对电压和功率密度的相对误差在运行温度为70℃、进气湿度为50%、电流密度为0.018 A/cm2时最大,最大值分别为7.306%和8.837%;提升运行温度和进气湿度均有助于改善PEMFC的性能,运行温度升高,膜电流密度分布均匀性波动较小,膜水含量有轻微降低;进气湿度升高,膜电流密度分布更均匀,膜水含量升高。研究为优化进气策略控制以及提高输出性能提供了新的理论方法。

In order to study the effects of temperature and humidity on the performance of proton exchange membrane fuel cell(PEMFC),a temperature and relative humidity-current(TRH-C)model was proposed.The model took the water flow and membrane water content of anode and cathode flow channels into consideration,and revealed the law of current density distribution and membrane water content distribution under the condition of current step change.According to the real flow channel configuration of the experimental single cell,a simplified PEMFC geometric model was established and the calculation grid was divided,and the TRH-C model was coupled to the multi-physical field calculation software COMSOL.A PEMFC test platform was established to test PEMFC under different temperature and humidity conditions.The operating temperatures of PEMFC were 65℃and 70℃,and the inlet humidities were 50%and 75%.The polarization curve,the membrane current density,and the membrane water content under different working conditions were analyzed and discussed.The results show that the TRH-C model can accurately predict the output performance of PEMFC.When the operating temperature is 70℃,the inlet humidity is 50%,and the current density is 0.018 A/cm2,the relative errors of the TRH-C model of voltage and power density both reach the maximum value,which are 7.306%and 8.837%,respectively.The performance of PEMFC can be improved by increasing operating temperature and inlet air humidity.As the operating temperature increases,the distribution uniformity of membrane current density fluctuates and the membrane water content decreases.With the increase of inlet air humidity,the film current density distribution becomes more uniform and the film water content increases.This work provides a new theoretical method for optimizing inlet air strategy control and improving the output performance.