Desigh Of Micro Direct Methanol Fuel Cell Stack With Concentrated Methanol Solution

Micro direct methanol fuel cell has many characteristics, such as a relatively high energy density fuel, simple structure and long discharge time. Because of these advantages, μDMFC become the preferred fuel cell research in the world today, while it has become one of the most competitive supply system in the new energy era.Energy density of methanol is 4800 Wh ? L-1, so theoretically unit volume methanol solution could be supplied with electrical operation for a long time. However, the high concentration of the methanol solution will have a strong crossover, causing performance degradation. As a result, most battery can work only using a lower concentration of the methanol solution. On the one hand it cannot fully reflect the advantages of methanol fuel, while fuel use will have a huge waste. Therefore, the research for using the solution of high concentration is necessary. And it has great significance to promote the commercialization of fuel cells.Firstly, this paper set up a theoretical model of DMFC with a high concentration methanol for mass transfer studies. Under the guidance of the theoretical model, we choose mass transfer barrier material and do some pretreatment for it. Then the structure of DMFCs and stack with high concentration methanol supply has been designed and packaged and finally tested. The results showed that: choosing stainless steel felt as the anode mass transfer barrier material can give a good mass transfer resistance for high concentrations of methanol without damaging electronic conduction efficiency in the whole structure. Then the battery with mass transfer barrier has been tested, and the results show that when using 7mol methanol solution for liquid, the cell gets the best output performance. The concentration is 2.33 times compared with a common structure of the battery. Then the stack has been tested and gets the best performance with 8mol methanol. This is mainly because the internal temperature of the DMFC stack rises when it works, the catalyst activity increases. Internal reaction becomes more severe, so the methanol concentration increases slightly. In addition, we also do the dynamic performance testing and long discharge test ing for the fuel cell stack with high concentration methanol. Test results show that the dynamic performance and output stability of the new structure cell stack are both good. So the energy density has been greatly improved, and it reached the ideal experimental purposes.