Study On The Performance Of The Direct Methanol Fuel Cell Based On The Influence Of The Ultrasonic

The direct methanol fuel cell(DMFC) as a renewable source of fuel can offer high power and energy density, low emissions, ambient operating conditions, and fast and convenient refueling, which is an appropriate power supply for electronic devices, such as laptop computers, cell phones, PDAs. Although many research works have made great progress, there are still some problems to be solved. The methanol crossover and catalyst poisoning are two primary reasons to limit the widely use of DMFC.In this paper, the method of using ultrasonic radiation to improve DMFC performance has been proposed. A new DMFC structure with three small ultrasonic transducers which is integrated in the anode flow field channel has been proposed and tested. The key component of the ultrasonic system has been designed and manufactured; as well the direct methanol fuel cell testing system has been built. And the testing method has been studied on the testing system. Finally, the cell performance and the open circuit voltage have been studied under different operating conditions. The main researching content is as follows:Firstly, in order to complete the project, the corresponding overall design of direct methanol fuel cell test system has been proposed. The key parts of the ultrasonic system has been designed and manufactured considering the conditions and influence factors of the ultrasonic cavitation generating. An experimental direct methanol fuel cell, which consisted of a membrane electrode assembly(MEA) with an active area of 5.0×5.0cm2, two bipolar plates with a single serpentine channel, three ultrasonic transducers(Piezoelectric Transducer, PZT-8), and transparent enclosures, has been designed and manufactured.Secondly, in this paper, to overcome the small low voltage fuel cell testing problem, the method of using the booster provide stable voltage and using electronic load remote sense function is proposed. The testing method can make compensation for the voltage drop on the conductor of the test. While, the accuracy and authenticity of the test results can be ensured by introducing reverse voltage protection circuit of electronic load into the testing circuit. The testing method proposed in this paper is simple, convenient, economic and affordable, and the feasibility of this method has been proved by theory and testing results.Finally, the performance and steady-state open-circuit voltage of DMFC have been tested under various ultrasonic conditions and operating conditions(ultrasonic frequency, sound power, the concentration of methanol solution) at DMFC testing system platform. Steady-state open-circuit voltage test experimental results show that methanol concentration are the main factors influencing the open circuit voltage of DMFC, and the DMFC open circuit voltage can be improved by improving the acoustic power. Cell performance results show that the cell performance can be improved by using ultrasonic radiation under the same operating conditions. The highest improvement of the cell performance can be achieved under the condition of system resonance.