摘要
建立了直接甲醇燃料电池(DMFC)(火用)分析的稳态模型,模型中考虑了甲醇串流以及各种不可逆损失引起的过电位的影响。在模型基础上推导出DMFC的(火用)效率表达式,并分别从电效率和热(火用)效率的角度出发,分析了燃料中能量的有效利用率,定量分析了甲醇串流率、电流密度、工作温度、阴极压力等参数对电池(火用)效率的影响,揭示了不可逆因素对直接甲醇燃料电池(火用)传递规律的影响。通过分析发现:燃料电池在运行过程中产生的热能(火用)在总有效能中占有很大比例,与电能相当,充分利用热量(火用)可显著提高电池的整体效率;电池在低电流密度下运行时,甲醇串流率过高是造成能量损失的主要原因;DMFC的总效率在电流密度接近极限电流密度时达到峰值,电池的工作电流应尽量控制在这一区间内。
An exergy analysis model for direct methanol fuel cell （DMFC） was established. Taking methanol crossover and overpotential into account, an expression of exergy efficiency which revealed the effects of irreversiablity on exergy transport were deduced. Further more, the utilization rate of energy stored in methanol and investigated changes of electric efficiency and thermal efficiency under various methanol crossover rates, current densities, operating temperature, and cathode pressure were quantitatively calculated. Some suggestions on optimizing operating conditions of direct methanol fuel cell based on the findings were also conducted. It was found that the thermal energy generated in fuel cell covered a significant amount of exergy in total energy and should be sufficiently used to improve total efficiency in a DMFC. Based on the investigation, the high methanol crossover rate is the predominant cause of energy loss when the fuel cell operates under low current density and total exergy efficiency of a DMFC reaches peak value when operating current is near limited density.
出处
《太阳能学报》
EI
CAS
CSCD
北大核心
2008年第2期234-240,共7页
Acta Energiae Solaris Sinica
基金
国家自然科学基金项目(No．50629601，50636050)
