车用质子交换膜燃料电池变载工况下三维、两相CFD数值模拟研究

Three Dimensional and Two-phase CFD Numerical Simulation of PEMFC under Variable Load

目前,成本和寿命是制约氢燃料电池汽车大面积商业化的重要问题,其中车用燃料电池处在变载工况是造成电池寿命衰减的主要原因。为研究变载工况电池内部动态响应机制,建立三维两相等温单体直流道燃料电池模型,在FLUENT中给定阶跃负载0.2-0.6A/cm2模拟变载工况,发现在变载瞬间单体电池电压从之前的0.743V立即下降至0.633V,随后经过12s左右质子交换膜内含水量的逐渐增加,使得电池单体电压逐渐上升至0.712V,揭示了电压的下冲量及响应时间取决于变载前后质子交换膜内含水量的重新分布。

At present,cost and life are important problems that restrict the large-scale commercialization of hydrogen fuel cell vehicles,in which the main reason for the decline of battery life is the vehicle fuel cell under variable load conditions.To study the internal dynamic response mechanism of the variable load cell,a threedimensional two-phase isothermal single fuel cell model was established.A step load of 0.2-0.6 A/cm2 was given in fluent to simulate the variable load condition.It was found that the cell voltage immediately decreased from 0.743 v to 0.633 v at the moment of variable load,and then the water content of the proton exchange membrane increased gradually after about 12 s,which made the cell voltage increase The voltage impulse and response time depend on the redistribution of water content in the membrane before and after the load change.