质子交换膜燃料电池的0℃以下耐受性

Sub-zero tolerance of proton exchange membrane fuel cell

车用质子交换膜燃料电池(PEMFC)应具备环境适应性,但水-冰相变会影响膜电极组件(MEA)。以-10℃及-20℃到正常操作温度的冰冻-解冻循环模拟实际工况,考察了水结冰对PEMFC性能的影响,结果表明:PEMFC的电化学活性表面积变小,扩散层的孔结构发生了变化,PEMFC的性能衰减。采用干燥N2吹扫、真空排水和RH=58.0%(25℃)的反应气吹扫等3种方法来避免水结冰的影响,发现经过冰冻-解冻循环后,PEMFC的性能均未下降。

Proton exchange membrane fuel cell （PEMFC） for automobiles should have enviromental adaptability. The phase transition between water and ice would impact negatively on the membrane electrode assembly （MEA）. To investigate the effect of water freezing on the performance of PEMFC, the simulating actual situation of freeze-thaw cycles from - 10 ℃ and - 20 ℃ to the normal operation temperatures were applied. The results showed that the electrochemical active surface area of the PEMFC decreased, the pore structure in the diffusion layer changed, the performance of the PEMFC degraded. To avoid the negative impact of water freezing, three methods including dry N2 gas purging, vacuum drying and purging with reaction gas （RH = 58.0% ,25 ℃） were applied. It was found that the performance of the PEMFC had no decay after freeze-thaw cycles.