Experimental Investigation Of Performance Of Fully Passive Small Direct Methanol Fuel Cells

Miniature passive direct methanol fuel cell do not have any pump and fans. The reactant of electrochemical reaction including methanol solution in anode and oxygen in cathode, are mainly transported by diffusion. Its volume, weight and electricity power consume by itself have been reduced by a large margin. But mass transfer resistance inside fuel cell causing little power is one of the most important reasons of output performance degradation of the fuel cell. In addition, portable power sources require that the fuel cell could oprate on and orientation. In this paper, experimental study about small passive direct methanol fuel cell operating at different angles of polarization curves and its dynamic response was in progress, the main research results are as follows:1 The first generation of small passive direct methanol fuel cell in our group was improved. Some of the main improvements including: methanol tank shell, methanol tank and the positioning plate, also increased the heating and temperature control system;2 The influence of temperature, methanol concentration, placement angle and other operating parameters on small passive direct methanol fuel cell was stuied. At the same time, in-situ visualization was carried out during static discharging, the results showed that:(1) Limiting current density of small passive direct methanol fuel cell with different opening ratio increased with temperature rising, corresponding to this, the cathode condensate water had also increased, but the extent of fuel cell affected by temperature with the increase of methanol concentration degraded;(2) Methanol solution concentration affected the small passive direct methanol fuel cell output performance. With the low concentration methanol solution, the performance of fuel cell at -45°in the concentration polarization was better than other cases, the amount of water condensate in the cathode was the least. But fuel cell at 45°was on contrary.3 Static performance and dynamic response of small passive direct methanol fuel cells with different opening ratio of polar plate was investigated.(1) With the current loading intensity increases, fuel supply in small passive direct methanol fuel cells with the opening rate of 40% was more stable than fuel cell which polar plate with 25% opening ratio, and its limiting current was higher.(2) While current loading in different waveforms, output voltage at high current loading intensity of the fuel cell in different wave was completely different. 25% opening ratio of the fuel cell was more obvious in short supply.4 It explored the dynamic response characteristics of small passive direct methanol fuel cell while loading in different waveforms and different slopes, and analyzed the mass transfer characteristics inside fuel cell when the current loading intensity changed.