零度以下环境中DMFC性能及传输特性

Performance and Transport Characteristics of a Direct Methanol Fuel Cell Operated at Subzero Temperatures

在零度以下环境中,直接甲醇燃料电池(DMFC)膜电极内的水结冰,将堵塞多孔层孔隙,影响反应物传输和电池性能。本文研究了-5℃条件下主动式DMFC的低温运行特性以及甲醇浓度、氧气流速和放电电流密度等参数的影响。实验结果表明:主动式DMFC可在-5℃环境中成功启动并稳定运行;此时最佳甲醇浓度为4mol/L,高于常温及以上条件下的最佳浓度;适当提高氧气流速有利于提高电池的低温性能;低电流密度放电更利于电池在低温下迅速启动和长时间稳定运行。

During startup from subzero temperatures the water in the MEA of a direct methanol fuel cell （DMFC） froze, which may block the pores of the porous layer and hence impact the reactants transport and the cell performance. The operation of a active DMFC under-5℃ was experimentally investigated in the present study and the effects of methanol concentration, oxygen flow rate and discharging current density on DMFC cold start and the cell performance were discussed. The results showed that the DMFC could be operated successfully and stably at a low temperature of -5℃. The optimal methanol concentration for the DMFC at -5℃ was 4 mol/L, which was higher than that for the DMFC operated at room temperature or above. The cell performance at low temperature was improved with a proper increase in the oxygen flow rate and decreased at an excessively high flow rate. A low discharging current density showed a benefit to fast start and long steady operation at the subfreezing temperature.