Research On The Influence Of Different Type Key Parameters On The Direct Methanol Fuel Cell Performance

Owing to low pollution,high energy efficiency and energy density,direct methanol fuel cell(DMFC)is considered as a promising power source for portable electronic equipments,transportations,military and other fields.Despite these advantages,methanol penetration,catalyst poisoning,cathodic flooding and other issues lead to DMFC performance and conversion rate is low at this stage.To solve the above problems,an effective method is developed to optimize the key parameters of DMFC.In this paper,the influence of operating and geometric parameters on DMFC performance is investigated.Firstly,based on the electrochemical theory model,the key operating parameters and geometric parameters of the DMFC are determined.The key operating parameters include the running temperature T,the methanol concentration CMe and the methanol flow rate FMe.The key geometric parameters mainly refer to the flow channel shrinkage rate ?.And then,a DMFC performance testing system is designed and built,and the testing methods of the testing system are determined.DMFC performance criteria mainly include the ?-? curve,the cathode outlet carbon dioxide concentration and the fuel utilization ratio.According to the experimental results,the relationship between the key parameters of the DMFC and the ?-? curve,the cathode outlet carbon dioxide concentration and the fuel utilization rate are analyzed,and the parameters of the DMFC are optimized by the multi-index evaluation method.The CFD simulation model of DMFC is established based on the experiment data to explain the relationship between the key parameters and DMFC performance.The results show that the optimal operating temperature T of the DMFC increases with the increase of the current density.In order to improve the DMFC performance,the methanol concentration CMe can not be too high or too low.The tapered flow channel which ? value equals to 20%performs better than the serpentine flow channel that 8 value equals to 0.And the effect of the flow channel shringkage rata ? on the performance of DMFC has a coupling effect with the operating temperature.The performance differences between the tapered flow channel and the serpentine flow channel are not obvious when the operating temperature is too high or too low.And in the moderate operating temperature conditions,the tapered flow channel with the ?value of 20%DMFC performance advantage is very obvious.