Research On CO₂ Remove Problem In Anode Of Micro Direct Methanol Fuel Cell

With the strengthening of people's consciousness to protect our environment and the deficiency of nature resources, people attach more and more importance to fuel cells which are considered as green energy resources with advantages of high energy, convenience and environmental friendly. Direct methanol fuel cell (DMFC) is the best portable power supply to enginery, notebook PC and so on which is developing rapidly.To tackle with the flow and distribution of CO2 that is produced in the anode side, a serious of geometrical model of flow channel was founded and numerical simulation was made using computational fluid dynamics software. In this paper, we compare the gas fraction distribution among a serious channel of different shapes and inlet conditions so as to predict where gas blockage would most probably happen, analysis the impact of channel shape, inlet fluid velocity, current density on the pressure drop and gas-fluid distribution.At the same time, self-breathing DMFC made by our research group had been evaluated in this paper. According to different shape, different inlet breadth of the anode channels, there were sixteen different anode flow plates consistent with twelve fuel cells. The anode channels were distributing in a area of 10mm×10mm, the whole DMFC was composed of anode layer, anode flow channel, MEA, cathode collector plate and cathode layer. The material of anode flow channel was stainless steel so that it can be used as anode collector plate. Between the flow channels and MEA, there were collector nets to collect electricity effectively. Anode and cathode were covered with PMMA plates.The testing systems for the self-breathing DMFC was composed of micro syringe pump, electronic load, pressure shift apparatus, DMFC and controlling computer. The two-phase flow pressure drop behavior in the anode flow field was investigated. The pressure drops between the inlet and the outlet of the flow channel were measured by varying current density. The experimental results show that at low current densities, the pressure drop increased with increasing current density. After reaching a peak at certain current density, however, the pressure drop began to decrease with increasing current density. It has also been shown that the pressure drop always increased with the methanol solution flow rate. However, either lower or higher rates deteriorated the cell performance.